A speaker enclosure, or “speaker box”, is a structure that surrounds the speaker and improves its sound quality by trapping air and controlling the movement of sound waves. The Thiele-Small parameters of the driver determine the optimal performance of an enclosure, with too small an enclosure leading to a pronounced bass peak and sharp rolloff. To achieve an optimum engineered design for a more focused soundstage, the drivers’ acoustic centers should be mechanically aligned.
There are five primary types of speaker enclosures and their physics behind their designs. Sealed enclosures are the most forgiving option, as they can be made in any shape and have non-rectangular shapes that avoid reflections or standing waves. Concrete is ideal for resisting vibrations, while finite “open” baffle speaker enclosures are ideal for a speaker driver. Sealed enclosures are the most forgiving option, but MDF has good acoustic properties at a low price but is heavy and does not hold up well to being bumped around.
For creating the front cavity of a speaker enclosure, common methods include using a screen or creating round or slotted holes in a solid plate. Vented enclosures are preferred due to their deeper bass extension, but sealed enclosures offer better power. Frequency response, impedance, and possibly harmonic distortion should be of interest, and for the enclosure radiation, it is best to use a metal or wood or MDF material.
In summary, selecting the right speaker enclosure depends on the specific needs and preferences of the speaker. Understanding the pros and cons of each type of enclosure can help you make an informed decision about your speaker’s enclosure needs.
📹 How to design speaker enclosure, basics | 2 things to get right in enclosure design
Good design is vital for successes in a speaker or subwoofer box performance. This first video about SpeakerEnclosureDesign …
What is the best material for an enclosure?
Enclosure material selection is crucial for ensuring safety, performance, and longevity in electrical enclosures. Metals like stainless steel or aluminum are ideal for harsh industrial environments due to their durability and strength, while plastics are cost-effective and versatile for indoor or less demanding applications. The choice of material directly impacts the enclosure’s performance in its intended environment, affecting its resistance to environmental factors like temperature, moisture, and physical impact. Each material has its own set of strengths and ideal scenarios, making it like selecting the perfect armor for a knight.
What is the 38% rule speaker?
The “38 rule” suggests setting your seating position 38 degrees from the wall in front of you to minimize standing waves in a rectangular room. This applies only if speakers are mounted in the wall, not on stands. To get the right listening position, calculate the sweet spot around that 38 mark. However, keep the triangular monitors/head arrangement and speakers within a meter of the front wall at most.
To improve acoustics without spending money, close curtains to soften hard surfaces in the room. Soft furnishings like sofas, beanbags, cushions, and rugs can absorb reflections. Bookshelves filled with books, records, and other irregular-shaped objects are less reflective than bare walls, so place them on any wall that can accommodate them.
In summary, the “38 rule” can help improve acoustics in any room by closing curtains, incorporating soft furnishings, and placing bookshelves on walls that can accommodate irregular objects.
What is the best material for speaker enclosures?
The article suggests that solid wood is not recommended for large speaker boxes due to its inherent resonance, which can disrupt the flat frequency response of traditional cone-type speakers. Instead, MDF veneered or particle boards are suggested for better sonic quality. Solid wood can be used for movement reasons, but it should be dovetail 5/4 or thicker for the four sides and float a panel in a groove for the front and back. A double groove and machined tightly are better options.
Spaceballs should not be considered. Quartersawn face and back panels should be used, and the joinery should reflect the use of solid wood. The author also mentions that wood makers often use MDF for speaker boxes due to its density and consistency, resulting in consistent sound.
What is the 1 3 rule for speaker placement?
The rule of thirds, popularized by Harry Pearson, is a fundamental setup procedure in high-end audio systems. It involves placing speakers and listeners one third of the total distance of the room from the rear wall and the same one third away from the opposite wall. The goal is to create a disappearing act in the living room, where the left and right loudspeakers are difficult to locate when playing music.
For example, in a 15-foot long and 12-foot wide room, the loudspeakers would be placed 5 feet from the rear wall, and the couch would be 5 feet out from the opposite wall. This is surprisingly simple and close to what you will end up with.
Mirror tweaks such as speaker distance and toe in can be made as needed. Rondi D’Agostino, 78, of Krell Industries, was a beloved and warm-hearted person in high-end audio. More specifics on these tweaks will be covered in a future post.
What are the two most common design types for speaker enclosures?
There are two main types of speaker enclosures: sealed and ported. Both are crucial in home theater systems as they should handle vibrations with ease and reduce sound interference from the speaker drivers. A flimsy speaker encasement can cause noise or fall apart.
Sealed enclosures are airtight cases that constantly change air pressure in the speaker, putting extra pressure on the diaphragm. This extra pressure makes the cone snap back and forth faster and with more precision, resulting in a crisper, more accurate sound. A flimsy enclosure can make the speaker system more noisy or fall apart.
What is the best placement for home speakers?
To achieve great sound with your speakers, follow these steps:
- Determine your listening position and position your speakers in an equilateral triangle.
- Ensure a 4 feet separation for bookshelf speakers and 8 feet for floorstanding speakers. Too close or far apart can cause muddy or gapped stereo images.
- Position your speakers at the same height as your ears, with tweeters handling high-frequency treble range.
- Move your speakers 2-3 feet away from the nearest wall to minimize sound reflections.
- Adjust the speaker angle (toe-in) to point towards the listener, specifically behind their head. Adjust the angle as needed to achieve good sound across a wider listening area.
- Ensure no objects stand between your speakers and your ears, and strive for symmetry in speaker and furniture arrangement.
- Isolate your turntable from speaker vibrations, keeping it on a different surface than your speakers.
These steps are crucial for controlling stereo imaging and sound reflections, which are essential for achieving great sound. It may take some trial and error to find the perfect placement for your speakers, but the end result is likely to be a great sound experience.
Is plastic or wood speaker enclosure better?
When it comes to loudspeakers, the choice between a wooden or plastic enclosure depends on the sound quality and portability. Wooden enclosures are ideal for loudspeakers with high sound quality, while plastic enclosures like ABS or polypropylene are suitable for portable and practical use. The cabinet of a loudspeaker is designed to prevent interference between front and rear sound emissions, maximizing transduction effect. It must be soundproof, rigid, vibration-free, and not resonate. The right choice depends on your specific needs and preferences.
What is the most efficient speaker enclosure?
Efficiency refers to a speaker system’s ability to convert electrical energy into acoustic output, indicating which system will produce the loudest output given the same amplifier size. In the 40-80 Hertz octave, the most efficient enclosures are the two narrow-bandwidth bandpass designs, with the dual-reflex version having a slight edge. The wide-bandwidth dual-reflex and ported enclosure also exhibit very good efficiency. The sealed enclosure and wide-bandwidth single-reflex bandpass are the least efficient designs.
For sub-bass to sound natural, the system must have good mid-bass capability. Harmonic components of sounds produced by instruments in the sub-bass range must be accurately reproduced in the mid-bass range for a system to sound accurate. In car audio, the ability of a subwoofer system to smoothly transition to the mid-bass region is crucial for achieving top-notch fidelity. Sealed and ported enclosures usually produce the smoothest mid-bass transition because the speakers play directly into the listening environment. Wide bandwidth bandpass designs are slightly more ragged but still deliver good mid-bass reinforcement.
There is no free lunch in enclosure design; each type has advantages and disadvantages. Analyzing the characteristics of each enclosure type helps decide which one is right for your application. Top-notch car audio specialists weigh all factors and consider all enclosure types before recommending a subwoofer system. The information presented here assumes that each enclosure type has been properly designed and executed, requiring the skills of a competent designer, installer, and cabinet builder.
In summary, efficiency in subwoofer systems is crucial for achieving high-quality sound. It is essential to ask competent designers, installers, and cabinet builders to explain their positions and ensure a well-designed system.
What makes a good speaker enclosure?
A speaker enclosure should be rigid and resistant to vibrations, with concrete being ideal for this purpose. Loudspeaker designers have various options for enclosure types, with wood being a popular choice due to its durability, lightweight nature, and ability to absorb vibrations. Wooden enclosures, such as MDF, also offer aesthetic benefits as they can be easily customized with color or finishes.
What is the golden ratio of speaker box design?
The suggestion is to create height, width, and depth in ratios of 0. 62 : 1 : 1. 62. This can be used for amplifying or reflecting frequencies using the golden ratio. The Golden Ratio represents the ability to draw a spiral of a seashell, which is the basis of galaxies, DNA, and sound waves. Connecting the points of rectangles will create a spiral of a seashell. While the subject is not specifically related to building a speaker enclosure, it is interesting to see how they are using this ratio.
Do speakers sound better in an enclosure?
Speaker enclosures are crucial for generating soundwaves and preventing sound cancellation. The front and back sides of a speaker create positive and negative air pressure, which can cause sound to cancel out. Without an enclosure, loudspeakers produce minimal bass response. Enclosures must separate the front and back of the speaker to prevent sound cancellation and manage the resonant frequency relative to the intended application. Enclosures are essential for gauging the acoustic properties of a loudspeaker and are central to its design and product performance.
📹 PLYWOOD vs MDF For Speaker Building – Tests Show Surprising Results
NOTE: This is to clear up some confusion over what I meant about bracing and damping: Speaker building was always bracing …
I have some large rectangle 6×9 speakers with the following specs (from what I can tell these are the ones that matter) Sensitivity: 91db Frequency response: 30hz-25khz (separate small 2 way grill mounted mid/tweet from passive xo) Fo: 45.272hz (is this the same as Fs?) Vas: 31.137L Qms: 2.444 Qes: 0.630 Qts: 0.48 What size sealed box would these need? Or if I go ported what size box and port? I have a six website amp that I intend to power four of these 6×9 and one or two subs. The 6×9 will be slightly underpowered, recommended 100w minimum 200w RMS /600peak the amplifier is capable of 4x70w + 2x100w in six website, 4x70w + 1x200w in 5 website or 2x140w + 2x100w in four website continuous power
NOTE: This is to clear up some confusion over what I meant about bracing and damping: Speaker building was always bracing and damping. But at some point the idea started that bracing alone was better, just using a lot more of it. Guys were still doing the traditional bracing and damping (like me), but you also started seeing these bracing only builds happening. The idea was to drive up the panel resonance high enough so that it wouldn’t be excited and therefore wouldn’t be a problem I’m speaking 100% from a DIY standpoint, not from what the major manufacturers were doing. Will making the entire box from the same material make a difference? Possibly, but I did what I could to take the rest of the box out of the measurement. For example the box was clamped down to my very heavy and stable workbench to keep it as stationary as possible, and help restrict the measurement to the panel itself. Yes the other panels were still vibrating and in turn that can affect the panel being tested, but it’s the same for each of the different panels. Each panel was exactly the same size – 8-1/2″ x 12″ with the screw holes in exactly the same places. Why 30Hz to 2000Hz? I did some “warmup” testing prior to the measurements I made to determine the best range that shows the most relevant data. 30Hz because the speaker I used doesn’t have significant output below 30Hz. I used my ACH-01 accelerometer connected to REW to run the measurements. I made a special preamp for that accelerometer in this article: youtu.
Looking at the location of the bracing, it seems pretty much in the middle of the box – so any panel resonances would be be at the same frequency above and below the brace, giving a single peak which is the sum of both sections. What I might try is offsetting the brace so it’s not symmetrical – I’d have to do the maths but my guess would be that the golden ratio might offer the best performance, giving two peaks at different frequencies which don’t sum to a higher peak like they would for a symmetrically placed brace.
I always put stuffing in the speaker box to stop sound waves bouncing of the clean walls and repeating back onto themselves and the driver. Remember when adding bracing you need to increase the volume of the cabinet because the brace takes a lot of volume up. I made a set of speakers years ago that had angled sides, multiple braces, stuffing, one coat of paint on rubber membrane them a second coat of rubber with sawdust added. Cabinets made from 18mm MDF. Still listening to them today. Good work on the experiments, it’s the only way to really find out!
Excellent and informative!!! I was a master installer at a high end shop for 9 years. Our material of choice was Trupan cabinet-grade MDF. Generally the enclosure was glued and screwed, then ALL inside surfaces were painted with latex paint to prevent ‘breathing’. For aesthetics all non-upholstered areas were painted as well. The material would leave talc-like sawdust and just EAT router bits and bearings if not fed or cut slowly.
Bracing panels forces us to think about the vibrations of the panel itself rather than the resonance modes of the internal air volume in the box. If we put reinforcements in the main resonance modal lines of the panels (1/2; 1/4, etc), creating symmetrical divisions, we will have 2 or more identical zones resonating at the same frequency (+3dB reinforcement). That’s why it’s recommended that the reinforcements be located in asymmetric divisions of the panel in question. You also have to think about the size of the resulting sections with the division. If a 12″ panel is split at the center, we will have 2 resonant 6″ sections; the ideal is to have zones no larger than 4 ” (this pushes resonances much higher than 1kHz, which eventually makes their absorption easier by passive means (foam, textile fibers, etc.) Several studies show that the vibrations of the panels are not perceived if they are 30dB below the main radiation (woofer), in the bass region (below +-300hz), the teorical “limit” is a little less (correlated with sensitive hearing curves) (the BBC did important research in the 70-80s for the development of its monitors, there are excellents papers on the web about the topic)
I remember that sound. I worked at Allison Acoustics in the ’80’s. Started out doing production. Worked my way up to testing. We tested components and finished speakers. Our cabinets were MDF with a fake veneer on the outside. Inside we placed a small amount of fiberglass.Never used isolation rings on the speaker basket or bracing. Dr. Roy had the cabinets made to his specs. Never tested cabinets. Interesting show.
There was a thick ceramic paint that worked well back in the mid to late 80s. Then there is the dampening material used in cars. There is something called no res that is pretty popular now. As far as bracing goes, it works well also, but it works better if it is rounded over on any openings and where it isn’t attached as this tends to not allow resonances aggravated by the right angled surfaces. Opinions vary on this but my research backs up the rounded over bracing as opposed to that which isn’t rounded over. The materials used were mdf so things may vary with plywood. Baltic birch is very good for cabinets, but not so much for speaker enclosures. MDF is more dense and has better damping characteristics when treated with surface coatings or other dampening material. Most manufacturers don’t bother with any dampening as this adds to cost. Failure to use any dampening causes resonance issues and DIYers and Modders have been doing this for decades. It isn’t a mystery.
Ages ok (mid-80s, I guess), a friend of mine had an old pair of speakers, something from the 70s, pretty standard stuff, just like the rest of the equipment. The drivers had paper cones with stiff suspension, the soft “rubber” wasn´t really standard at the time those were made. Those speakers were ok, but down low their resonance made them sound quite undefined. After a little thinking about it, we removed the drivers, measured the inside dimensions and cut a few pieces of wood, about a 16th oversize, wedged them between the centers of the panels and remounted the drivers. The low bass got much better, it sounded much more responsive and defined. It still was far from comparable with higher-end contemporary stuff, let alone modern equipment, but it was definitely an improvement.
Thanks for this. I know why your results don’t show dramatic changes. Your whole setup is wrong. You need $6000 pure silver speaker wires, a $1200 jar of aquarium gravel in the corner to absorb standing waves, and a $14000 9 Watt vacuum tube amplifier because solid state couldn’t possibly be good enough for such tests. I’d love to see the same test with concrete. Yeah, it’s ridiculous to work with but it really does make a good speaker box. A simple 8×16 patio paver, make holes, you can figure out the rest.
Solid experiment. I am in the process of designing and building some sealed 15″ subs. my plan is to use 3/4″ BB and laminate a 1/4″ MDF to the outside.. My thinking is that the BB is lighter than MDF so the subs won’t be as heavy as using all MDF, but the MDF outer layer will make the veneer application easier.
About 40 years ago I built a set of 3 way tower speakers using 1/2″ particle board with 1/4″ Luan plywood laminated on the outside with for a nice looking wood finish. They are still going strong and the cabinets are still solid as a rock. The only inner bracing was a divider between the woofer and the midrange/tweeter section, to make the woofer section the right volume for the speaker that was used. I also put fiberglass insulation in the woofer section. I know particle board isn’t really desirable for speaker cabinets, but even at high volumes the cabinets show no signs of vibration. I keep thinking that I’ll rebuild them some day, but they’ve been such good little troopers.
On my last speaker building project I used a knotty pine butcher block style project board from Lowe’s. It’s relatively inexpensive and beautiful with a bit of oil on it. There’s no reason to fret about the material resonance if you address the resonance with bracing and damping materials. I lined the largest sections of panel with asphalt/rubbery type damping sheets, then used acoustic foam, then poly-fill. The result is a plenty-quiet cabinet and a beautiful knotty pine butcher block finish that required no nonsense to “finish.” Just a rub down with some oil to give them a bit of rustic sheen.
Very interesting and very informative. I never liked mdf. It always seemed to not be stuff enough and therefore would require a lot more bracing. The effect of insulation on high frequencies was interesting. I would assume that it would be due to dimensions of the box creating “room” modes inside the box? Thank you. Very helpful.
This is a great project with good discussion. I would suggest that you could test the speaker cabinet in a free-free condition by supporting it on some soft foam. This would also eliminate the boundary condition created from clamping the wood panel through to the bench – this will likely affect the panel resonance and modes.
Very interesting, John! I’m guessing the pine ply had the lower ringing due to the varying thickness of veneers, which make each layer less sympathetic to adjacent layers. I like to use two layers of granite, one being 3/4″ and the other being 5/8″, laminated with a layer of 1/4″ lead sheet. Let the tone wood debate begin😁 Thanks again for taking the time to test and share. Awesome!
My initial guess would have been that particle board would be the worst, with OSB and various plywoods in the middle and MDF the best, so this seems to confirm most of that. I also remember some inexpensive speakers from the 1970s with dense Styrofoam enclosures that sounded much better that I’d have expected: not much mass, but maybe a lot of damping; a test on that would be interesting.
I’m pretty new at speaker building. I admit that I was surprised at how cheap most companies build speakers. Fairly expensive(for me) brand names tend to have cheap speakers, thin wood, light gauge CCA wires but made the cabinet look real nice and fancy. I ordered some actual Pioneer speakers, crossovers and build 1/2″ thick sealed but ported cabinets and used copper wire for 1/8 what a nice pair of Pioneer cabinets would cost and they sound good. They’re not as pretty or expensive looking but genuinely sound better than the most expensive speakers Ive heard. Of course, the source has a lot to do with it but I am comparing these I build with a $800 pair of Fishers I own.
Another top tip is to laminate a panel of mdf to the inside face of baltic birch. This improves(reduces) time of resonance. Bracing works by lowering amplitude of resonance and shifting frequencies further up. Creating sub panels by multiple braces unequally spaced makes them effectively different sizes and splits frequency of resonance hence reduces amplitude of each specific frequency. Equal spacing creates lots of sub panels of similar frequency so doesn’t reduce amplitude which becomes additive. Using 5 braces has a similar effect on resonance amplitude as doubling panel thickness so increasing nr of braces to more than 5 has no advantage over simply doubling panel thickness except that the larger the cab the lighter you can make it by upping nr of braces. Using visco elastic damping membrane on inside panel faces drops resonant frequency and lowers amplitude and time of resonance. There’s loads you can do. As speaker size increases so mass increases and structural integrity becomes more important. This is where baltic bitch ply is superior as it has greater integrity through higher tendsile strength and greater resistance to shear as well as splitting compared to mdf.
Top secret tip: Glue together full sheets of 1/2″ plywood + 1/4″ MDF board with a synthetic rubber based adhesive. Rip and cut panels with regular tools just like using a thicker board. Use plywood outside for durability & MDF inside for good damping. This combination has, by far, the best properties for nearly eliminating cabinet resonance. Beats every other type of wood. The only thing better is rubber reinforced concrete. That stuff is impossibly heavy though!
About 40 years ago a friend of mine had his brother build him a pair of speakers. The cabinets were plywood and the drivers were from Radio Shack. They stood about 3 feet tall, 2 feet wide and a foot deep. To this day they are the best sounding speakers I’ve ever heard. I need to ask him if he still has them. My guess, the drivers have turned to dust by now, but it would be a cool re-build with modern drivers.
I doubt the test will show anything worthwhile. The other 5 sides of the box are made of some material, which when it vibrates will transfer that to the top panel. So the test wont correspond to a whole box built from each material, it will be confounded by the energy transferred from the other sides, which will be more or less efficient depending upon density, young’s modulus etc. You would either need to build a whole box from each material, or use thick welded steel or concrete to make meaningful comparisons.
What would be interesting would be larger dimensions, which would create greater spans, thus creating larger vibrational areas. Say, 48″ x 32″ x 32″, creating a more concert size speaker cabinet. Such a small test sample as the one herein, will automatically have minimal vibration, just because of span. Thanks much for your test! Enjoyed seeing the data..
I used MDF in hundreds of enclosures as a box builder for car audio shops in the 90’s and 00’s. I developed an allergy to the stuff over time. The glues or binding agents used in it are prone to gassing off when temperatures get above around 80°. It kills my eyes and nose. Anyway, I started using birch hi-ply plywood over 20 years ago and can’t imagine going back to MDF now.
Thanks John, this is very opportune for me. I’m about to build a pair of mass loaded transmission line enclosures. The design is heavily braced and the designer just mentions ‘good quality multi-ply’ . So I’ve been agonising about 18 mm Baltic birch or hardwood construction ply. Both are expensive in the UK at present, Baltic birch especially so and it’s not easy to source. So I’ve been thinking – will I hear the difference with ordinary ply ? Sure it’s lighter and less stiff than birch, but …. So I’m going to use ‘regular’ hardwood ply, not Baltic Birch. It’ll be veneered anyway. Really enjoy these audio excursions.
Thanks for documenting the experience, some thoughts come to mind. A loudspeaker enclosure is a 3D structure which is most often heard also mounted on a stand, the resonance modes of such a structure are not necessarily the same as the resonance modes of a single panel firmly attached to a heavy woodworker’s workbench. Plate theory offers good ways to predict the modes of a rectangular panel made of isotropic material, but the analysis of the “3D” modes of the entire enclosure on a support is much more difficult to predict. Add to this that opposing panels could resonate additively and radiate sound into the room, but could also have modes in which they move identically, hence subtractively, and therefore do not radiate sound at a distance. I fear that it will be necessary to build an enclosure entirely and measure the accelerations of the opposing panels to be able to accurately compare the influence of the materials used on the distant sound field. Would be super interesting to also add other type like HDF, Bamboo ply, CLD with polymer, …
I would have to disagree with you sir. Using 100% solid wood for the builds.. aka hardwood for those don’t know. I had built me, some towers years ago out of Tiger maple.3/4″ finished. R13 lightly inserted. Looked amazing but certain frequencies produced a tiny type sound. Later… I had tried this again out of 3/4 finished red oak and paint grade Hickory. The boxes had a very tiny sound even with R13…. best described as, a speaker in a metal coffee can. Again at certain frequencies. Recently I had made another set of towers out of solid pine. “Barnyard speaker build. ” They sound amazing by comparison. No echoes, reverbs or that tiny sound. I think your test should be done free standing and all 6 sides of your cabinet made from the same material.
thanks for posting some actual testing verified with results. I like your questioning attitude. As for the resonance issues if you look at the speakers often used in sound reinforcement in live performance and DJs they are mostly molded plastic and iff the equipment is set up correctly for the room some of them sound pretty dam good . Like any musical instrument like all the horns wood winds and brass it is primarily the size and shape of the cavity not the silver and brass that make the difference between OK and great sound.
This is interesting, and I suspect your conclusion is valid. But I’m also trying to figure out how much the resonance of the other sides of the box will affect the one you measured? The scientific thing to do would be either to make the box as non-resonant as possible, or make identical boxes from each material. The lack of significant differences may have something to do with the fact that 5 of the 6 sides were the same in all the tests. But it’s impossible to know without more testing.
The same experiment was conducted on another website I’ll Fargo the websites name out of respect to your website. In their conclusion they found out that plywood was superior than MDF material and that marine grade plywood which is very expensive was the best to use to make a speaker box. The only problem is the cost of the marine grade plywood to MDF. MDF was about half the cost the MGP would cost.
Lots of good stuff. Well done! But I am confused by some of the explanation. I built my first set of speakers, large cabinet 12″ 3 way, in the ’60’s. I used both filling material and random placed bracing. back then. Perhaps things had gone out and back into favor? Also I understood the filling to lower response curve by adding extra absorption internally. Reduced ringing was secondary.
I like experiments like this. I believe the materials would have shown a greater difference if the accelerometer placement was on the speaker baffle itself. I realize that entails more work. Also, it would be enormously interesting if you had also tested a constrained layer damping material applied to the inside of the baffle such as Dynamat Xtreme. Also, there are manufacturers such as Magico who make cabinet enclosures out of billet aluminum and carbon fiber. They also apply damping materials such as No-Rez to the insides. Thanks!
OUTSTANDING article!! Wonderful to see some empirical testing on enclosure material resonance. You confirmed a number of longtime observations I’ve made myself. Personally I’ve found that a combination of bracing (of different types used in the same box) and the use of laminated panels is very effective at eliminating resonances. If you glue a thin (1/4 – 3/8) panel of (quality) MDF to a Baltic birch plywood panel, the result is amazingly stable. You have to use a lot of glue, and make sure it is uniformly clamped together, but it’s worth the effort. Many of the high-end speaker manufacturers utilize composite layers of different materials to absorb resonance. The key is using materials with different *densities*. When the energy hits material A it bends at angle X, for example. As it passes from material A to material B (of a different density), it bends again at angle Y and so on… Each change in direction absorbs energy. I’m an instant fan of your work, thank you!
I’ll chime in on this one 🙂 Those drivers are not going to benefit from speaker material as much as a subwoofer. Typically when I discuss material types I try to differ the speakers. Resonance just simply will not show in a enclosure of that size and a woofer of that caliper. Use an 8 inch Subwoofer and you will detect a huge difference. One way to consider is that Martin Logan uses MDF in their 25k tower speakers.
It looks like subwoofers would work better with mdf it read higher in the low hz 100 down. But I don’t like useing it eather every were you hear all the great things about birch. So that’s what I’m gonna use for a 15 sundown I like the thought of being able to stain and clear the wood an how good it will look ! The caricatures of the wood grain with all the detail wood grain has it’s beautiful! They say it’s stronger and lighter then mdf so I’m gonna find out this is a gr8 article and thanks for sharing it nice to have this info I’d like+to see if there would be a major difference with this for lower frequencies like with a subwoofer from 20-250 hz I think I’m gonna do the rubber inside my ported box’s but sealed I just paint them heavy I could tell the difference between painted and not also is I put pillow filler in one seemed like it was a better sound but I’ve only built subwoofer enclosures most sealed but I’m learning ported ones !
Very interesting results! My only issue is that I am interested in building speaker enclosures, but from the perspective of a guitar amplifier. And it seems the goals of hifi designers are at odds with guitar amplifier builders. Whereby the hifi designer doesn’t want anything to influence the driver, and amp building considers the cabinet as an instrument unto itself. So we’re looking for that magical cabinet resonance, whether it really exists is up for debate.
I was thinking of your measurements vs listening comment. If you had two sets of boxes made the same but different materials (maybe most different in your test) and could do a controlled, anonymous, blind test of them, you might hear a difference. But, my guess is some would like “A” better and some would like “B” better. Also, experience tells me that you would also get used to listening to either over time.
I dont see MDF being so great, many layered plywood is defen. harder and still a mix of pieces with different qualities, while the MDF is homogen. The best material in this case is actually corean (by Dupon) it has the perfect mix of materials to dampen sount inertially by itself. (because of the mixing of materials with so different properties causing nullyfiying out themselves)
Calculate, build, measure == engineering. You might like calculating the expected panel frequency to see how close it was for your build. Really great to see the build and measurements. I build boxes small enough that the lowest cavity resonance is above the range I will use that driver. I do the same with the panel resonant frequency. If the panel is thick enough and small enough or braced sufficiently, the first resonant mode of the panel can be placed above the range the driver is used. Stuffing the box with very dense wool or fiberglass completes the package. A fully non-resonant enclosure. You do best to make the box the shape of a half cube with the driver centered on the large square side. I don’t think you can do better than that.
Nice article. But I will disagree that this effect is inaudible. When you listen to a pulse measurement, either behind or to the side of a speaker, you should hear a single “shot” or crack. If the cabinet is not well constructed and resonant, what you hear is a very distinct “boing” as the speaker cabinet smears out the pulse. So, definitely a special case but also certainly audible. Hope this helps.
You talking about membranes gave me an idea and Im curious if you’ve ever had this thought or tried it. Are you familiar with Rhino Lining for cars? Its a spray on tough lining meant for truck beds to protect them from use. I’m curious if something like that would have any positive/negative effects on a speaker box. Cheers.
I build speakers too and the crossovers. I use the 20mm pine ply for my speakers and I brace them with thin dowel by glueing the ends to the box panels across the speakers inside (several of them front to back and from side to side). I did it to save internal volume but maybe it’s better than normal bracing, going by your results. Interesting that it makes such a measurable difference. Great work dude. Cheers Big Ears!
The test rig looks clamped to the table. Most speakers are freestanding. Mass or density of the material will make more of a difference in that situation I think, maybe? I would be interested to know for certain. As to whether you can hear it, that’s much harder to determine. There’s definitely no harm in trying to minimise resonances if the cost isn’t prohibitive.
The thing to look at is stored energy in a water fall plot, that tells the real story of what the cabinet does to the sound, stored energy always shows up in listening tests, either as muddyness in bass or something in the vocal range that you can’t quitee put your finger on, but it wearing over listening time !!
First off I love the article however I think you would have had much different results if you would have built four separate boxes out of that material entirely meaning don’t just count on one side get the results from it and call that proof that leaves variables on the table too many in fact I would have loved to seen four separate enclosures and do that sweep to see the difference I bet it would be more drastic
The only way to find out if you can truly hear the difference between materials is to arrange a BLIND listening test, where you cannot have your own bias affecting the results. If you can’t or won’t do that then anything you say is suspect, and measurements will be more reliable. I used to know a studio technician who had an amusing hobby; proving to people that they could not hear things they swore they could hear. He would regularly conduct blind listening tests to prove to people that they could not hear the differences between a vinyl record and a digital recording taken from that vinyl record, for example. Not one person ever managed to get a score better than guesswork on that one. Lab measurements are far more reliable than listening tests unless the listening tests are properly conducted blind listening tests.
This is a great test in the analysis, but I think that maybe clamping the speaker box that way, and using it for every test, leaves only the front panel where the speaker is mounted as a variable. Internal reflections could show more with no clamped boxes fully made of the same material. Again, it’s still a great test, cheers.
It would also be compelling to me to see corresponding results measured with a calibrated mic on axis with the driver and also 45deg on a box edge to measure if any of the higher frequency ringing was actually causing the edge to become a point source (I’d doubt it since the frequencies are generally so low).
Hello John and anyone else who might know: Does the shape of the enclosure matter much for the over-all performance of the speaker? I once read that an enclosure following the (iirc) golden ratio (something like 0.6x1x1.6 depth, height, width) was “a good thing” for speaker performance, but it wasn’t explained why. Does this idea hold any water, or is it just more wishful thinking? Thank you!
I like the end takeaway. . try to be objective in your subjective listening test. Thanks for doing these tests and confirming what I wanted the result to be. (always helps accepting results that match with your desired result, right?) 😜 I’m wondering if this would change much with larger, floorstanders or sub enclosures that have significantly more volume. However, as you pointed out, an adequate amount of bracing may be the key takeaway. There probably won’t be long, unsupported or unbraced sections that would vibrate at resonant freq of the material anyway. And if so, then it may be more of a problem with the design or lack of bracing rather than the material being used.
Re: can it be heard? How about an (admittedly another indirect) assessment of the worst outcome? It would be interesting to look at the THD of the frequency of the worst level resonance peak among the different materials. It it’s 0.1%, then declare it “unhearable” along with all the other lesser amplitude resonances. If it’s 25% — then pitch it as the perfect material for guitar speaker enclosures?
Wondering… Would the holding/clamping method and variances in clamp pressure on the surface tested not influence the results? I’m thinking screwed down from the inside at the corners and center (or perhaps kreg screwed from the outside around the perimeter) would have more consistent and accurate results?
Porous vs. Non-Porous smooth. Wood vs Glass or Glass-like does have an impact on cavity resonance, frequency response. As a simple example, take a high end classical guitar, the type of wood will have an impact on sound, but it is also a matter of volume, geometry and in the case of speaker enclosures the electrical components (drivers and X-over network). Formica applied with contact cement, as a finishing laminate over MDF or Plywood, in my experience adds a more solid enclosure which holds sound rock solid provided the box is sealed, ported and tuned properly.
I remember well in the 70s all British speakers were made with chipboard. Then the BBC started doing tests on cabinets. They concluded that plywood gave a higher frequency resonance but was easily dampened by bitumen panels glued to them. Chipboard had lower resonance but was harder to remove. It was not long before a number of British speaker makers also started using ply with damping panels. Spendor, Rogers etc. These were very good sounding speakers, was it because of the ply or were they just better speakers?
I built a pair of small satellites and a pair of large bass boxes using 3/4″ oak laminate plywood and they worked out quite well. My concerns with using plywood are twofold, first, that they don’t lend themselves well to gluing on bracing on the inside of the panels, since the brace would be glued to the first layer of plywood only, and second, that over time the plys may begin to separate and rattle. For my latest boxes, I went back to MDF, since with the oak laminate material, I still had edges to cover, and with the MDF, I used oak laminate sheets to cover the entire surfaces of the front, top and sides. For internal damping, in the past I have glued carpet padding to the inside panels using carpenter’s glue (called Powergrab) applied to several places on the padding. For the last project, I purchased water based roofing cement, and brushed it on both the inside panels and the carpet padding, applying quite a thick coat, and glued the padding to the panels, this provides both dampening of the panel and absorption-diffusion of sound waves inside the box.
Interesting results. The only issue with plywood is the strength of the joint with end grain if you are just using glue; there are ways to deal with that though. I used plywood for my Infinite Baffle manifold to get strength. I would not want to hang 4 15″ drivers to a MDF box attached to floor joists. I did glue and screw it though, and with opposed drivers, a lot of the energy induced is cancelled out. Thanks for doing the test. MDF machines nice, but is a PITA dust wise….
Even if this article is two years old, I would still like to ask about an idea that I had some time ago to dampen or at least move higher the resonance frequency of the speaker box. That is using long 1/4″ thick threaded rods, preferably brass, running between parallel walls/sides, and to tighten the side bolts as much as possible, also adding tightened bolts on the inside. That should “contain” the vibration. Do you think it might effective? The advantage they have is they use very little internal space, and they could be easily added to an existing speaker box, bought recently or not. There’s a YouTube series by GR where people send their flawed speakers they are not happy with, and the usual suggestion they get (besides buying better, more expensive parts for the crossover) is to use an expensive damping material they sell, and sometimes to add wood damping plates or crossbars to the inside, which would modify the internal volume somehow.
I think your comparison of 1/2″ and 3/4″ box would show a larger difference in a bigger box. When the span is longer the thicker material is going to be stiffer. So if your building a small box, go ahead and use 1/2″ material, but if your building a 4×12 guitar cab 3/4″ material would be better suited.
Mr. Heisz, great article thank you. I must ask you however, how close to the manufacturers rear spacing did you build the box and why didn’t you test the sound board instead of the side of the box? I’ve been building speaker boxes for about 60 years and one of the problems I’ve found is that after a lot of use the plywood seems to delaminate causing unwanted vibration, even with the better quality marine plywood, which has all voids filled unlike regular plywood.
I would be interested in seeing results for Particle Board, Orientated Strand Board, and a thicker plywood such as 1-1/4-inch High Density Overlay. I did some tests on resonance of Portland Cement Concrete slabs, when I was an undergrad, and have always thought about builing something similar to a Klipsch Folded Horn with 1-1/2 to 2-inch thick concrete walls.
It seems like a lot of box designs are focused on preventing the box from coloring the sound of the speaker elements. Could speaker boxes be built like musical instruments where the box surfaces contribute to the overall response of the system as a whole? I suppose this has been explored with tactile transducers and electrostatics.
Hi there. I am building a pair of line arrays and since I have little or no acces to MDF I have been considering using 1″ PVC of the highest density(.60) available and even dual 3/4″ for a 1.5″ panel. How should that compare to wood? I am not sure if I will have any access to pine or baltic birch either…
Sikaflex sfc 11. Windscreen adhesive. Bond 2* 1/2″ panels together with a 1mm layer and a weight, don’t clamp! Then cut to size and assemble the box with the same. polyurethane adhecive. Warning! It’s messy. Dampens beautifully. You can also ‘plate’ the inside with 1/16 steel plate with the same adhesive. The plates mustn’t touch any corners or braces, so make them 1/2″ smaller all around. Ps, the damping test should be directly behind the driver.
@IBuildIt A few years ago I renovated a pair of heads (MDF) with a 12″ bass and a 1″ tweeter with a 30cm horn – with a multiply (9-ply) beech wood exterior and a vented cabin. I dont like MDF, it’s really cheap material and parts of the corners were broken off, I remade it. There was a big difference: clear, clean, no booming, that’s why I decided to use the next cabin – RCF 18″ ventilated (approx. 100 cm high, 70 x 70 cm), old: MDF, new: Mulitply – also there a big difference in the sound! I think because the MDF is softer, and the Multiply is much stiffer, minimal bending, so in my opinion there is less cushioning and more comes out of it! The best part is that the veneered surface makes it easy to get a brilliant finish, I use epoxy resin as glue, after 10 years no problem, no shrinkage, no leaks – and 3 coats of epoxy resin outside – the best result you can expect your work can achieve! My last project was an Electro Voice Eliminator – a 2 x 15″ cab – a big deal, a lot of work – but in the end it rewards me doubly every time I play with it.
Ok. Let’s clear something up. I have an 18in subwoofer. It handles around 2k watts rms. Do not use 0.5in plywood or mdf. Does 3/4 make a difference? Oh yes. Does it still flex without braces? Yes. To say 3/4 is only marginally better than 1/2in is misleading. Maybe in your small low power speaker, but in higher power more dynamic speakers the thicker material will shine. Type of material might be less significant than thickness, but for a powerful speaker more is better.
INice article, so important to actually have tests and measurements. Interesting when you have ultra high end audio where concepts are brought to reality often. Totally having inert boxes has been achieved but some find the resulting sound a bit analytical guess many wants to hear favourable resonances to a point so now many speakers are designed specifically with resonances in mind maybe not as much as Harbeth boxes.
Interesting test. This pretty much confirms what I have heard by ear, in that there isn’t an audible difference. I switched years ago to mostly baltic ply, for the reason that it’s consistent thickness for the CNC, and that it’s much harder than mdf, making a more durable end product. MDF dents and bends corners too easily. I also played with corian and phenolic, but again, the advantage wasn’t sound, but rather a more stable material for finishing. If you want that Wilson finish you need to lay down a really thick layer of spray filler to encapsulate the joints, then wait months while the material settles down, swells, shrinks, and moves. Then and only then do you dare block it for primer. That said, take a close look at a wilson and even they have issues with their materials. You will plainly see the joints through the automotive finish.
Your test and assumptions are flawed. You should’ve built different boxes. 1 made entirely of baltic birch plywood, 1 made from MDF, 1 made from Construction Grade plywood, 1 made from Pine Plywood and compare the results of the four boxes made from all four different materials, you compared the back of the box made from a different material. Cabinet Resonances do not travel in one direction only. Also you didn’t take into account the front baffles sharp 90 Degree corners which also have reflections. The majority of speaker cabinet manufactures chamfer the edges of the front baffle to reduce the reflection from the drivers. Also great loudspeakers designers who are audiophiles use special microphones with the bottom of the speaker cabinet sitting on a stand approximately 28 – 33″ high and the center of the tweeter positioned at ear height of 40-46″. The microphone will also be positioned in the center of the tweeter from 3Ft – 6 Ft away. They set them up a different distances to test the frequency response and the sweep measurements. They also will try hundreds of options to keep improving the sound quality of the loudspeaker with not only the drivers the cabinet build quality but also the crossover network and the type of crossover network parts. They won’t buy cheesy crappy parts for a few dollars either! There’s a company called GR Research, Danny’s been designing Loudspeakers for 20 years he is an expert on the subject! he may go through 100 reiterations to design the almost perfect loudspeaker less than 1% of all loudspeakers manufactures do this!
would like to see some comparrisons with ply vs straight wood. i know ply gives a more even material but do all those resin layers make a difference? maybe 9layers of glue in baltic birch has more effect than the included hardwoods.. ive tried workong with bloodwood recently. some tough arse dense wood. that instantly got me looking for large panels for speakers..only about $400 per plank😂 so sod that. but a guy can dream. so..ive got some 1×1.5×12″ bloodwood lengths, those will be made as a sort of brace to help disperse the sound through the wood. what you can with what you got 😂
I like MDF because it’s readily available and consistent thickness and I don’t like getting gouged every time there is an environmental issue disrupting the plywood supply, that tends to leave most of this impact expense permanently in place. I saturate my MDF with thinned epoxy that turns it into a very resilient composite. Otherwise, I have not heard sonic differences between different type panels. Also not a fan of odd sized panels, and metric equivalents that always favor the smaller dimension. I have bought some plywood marked as 3/4″, that is closer to 5/8″, especially when the full .75″ is needed for structural concerns.
Thank you for making this article! For decades I was wondering if plywood was better MDF (plywood is stiffer for the same thickness). In audio circles, many people claim that MDF and HDF are crap as far as acoustic behavior is concern. So, you masterfully shed some light on this topic. Should you have made a whole cabinet of each material to have a clearer result? In any case, this is a very complex subject with a lot of long held beliefs. Thanks again!
Makes sense just like metal work or anything structural. To make the same thing using different materials requires more or less bracing. Thin metal or wood requires more bracing to be as rigid as harder metal or wood. Along with thickness. This is good. I want to make my own 2×12 guitar cabinet. With wood prices being what they are I’d like to go cheaper. Heck, could even use a wood enclosure with some metal bracing.
how many musical instruments use stuffing. its a patch on a flaw. im building some atm using some 48x12x1 solid oak from an antique table for the fronts, the sides ended up plywood, but i have allsorts from mahogany to bloodwood tjrown in there. for me im aiming to use the different densities to help form the sound. i want some projected, some to resonate to certain areas. some is thinner and the base/skeleton of that lower is about 5″ thick. its all shaping that sound pressure…my speakers are cheapo daytons, i believe in the boxes as instruments. hell ive even got inch thick brass lips for the voigt bit.😂
This is why I made my guitar amp speaker box out of fir and pine. But.. if I’m not mistaken, it’s not the actual sound of the box that it produces while resonating that’s audible, it’s what the shaking/resonating of the box does to the drivers as it shakes in and out of phase with them. That’s what you end up hearing as artefacts in the sound. The volume would have to be ear bleeding in order to actually HEAR any sound from the enclosure itself.
I guess stuffing becomes less important the lower in frequency the driver is playing? Say if you have a very stiff, well-braced box, but the driver is a subwoofer only playing up to 100hz or so stuffing really is pretty irrelevent as all the box vibrations are well above the frequency at which the driver is playing. But say if your driver did play into the mid-range, it would be worth adding stuffing in addition to bracing to damp out those higher vibrations.
No it won’t make a big difference in a tiny space like that with a 12×14″ panel but once you get to areas with 30+ inches with braces only every 12+ inches there’s a huge difference in vibration|flex and if every panel is made out of the same wood and not just one of the panels the difference would test double or triple the difference of what your chart shows since it’s all the wood vibrating and not just a single panel.
Some fundamentals to remember. The filling of a space with absorbent wadding is there to reduce the internal standing waves that get energised by the speaker and augmented by the parallel sides of the box. This problem will be most noticeable where the internal height, width and length are half wavelengths. It’s considered that the best place to put the wadding is in the centre of the acoustic space. Reducing the standing waves minimises the energy transferring to the cabinet sides reducing the colouration. Cabinet wall thickness, bracing and damping is about minimising the energy transferred from the inside to the outside of the box. Either make the panel very stiff and possibly move the problem colouration up in frequency into the region where the ear is more sensitive as a consequence, or allow it to flex slightly with thin walls as long as it’s very well damped, thin ply with bitumen dampening panels for instance, keeping the resonance low in frequency where the ear is less sensitive. A quick tap test on the cabinet sides will tell you which is which. Either way you are still going to get some radiation of sound through the loudspeaker diaphragm from the cabinet interior.
What do you think about using rubberized undercoating on the inside of the box the article I seen about coating the inside with it and they say it won’t let the wood absorb the sound they were ported boxes I was thinking about braces and the rubberized undercoating 1 box for a15 inch sub with a 8 inch round port and a dual 12 inch sub sealed but I like the article at least you know there is no wrong wood to build from I’m like you on hearing the difference but I’ve has people say they could feel the difference in how hard they hit I always just try to stay spot on the manufacture requirements for specs I seen also the ply woods are stronger & lighter than mdf I think I will go with plywood I think I might like the stained and polyurethane look on the box instead of the carpet thing but I might use both have something really different again great article like all the info I can get .
If you want to get a better test result….. build the exact same box out of the entire material for each. I’m prety sure you will see that the difference is much more noticeable when the entire box is made of the exact same materials . Trying to measure just one panel it’s not going to be as accurate as measuring when the entire box is all of the same material. This is because the sound will travel through all of the walls of the box. This amplifying and or exchanging that to the next panel. But then again maybe I’m wrong. Would definitely be interesting to see if it does indeed make a difference. I know that it has in other kinds of materials
I dont know much about this type of thing. In my mind running a sweep through a speaker tells you some things for sure but when music is playing the speaker is doing so much at the same time. I would like to see more comparisons of actual music being played through these different scenarios rather than a sweep. Maybe the differences will be more apparent?
Bracing alone was only ever suggested for subwoofers, where the frequency range was limited. Damping is still useful even there, though; especially when trying to cram a woofer in a box that is smaller than recommended. Also, there is a difference between volume damping materials (stuffing) and wall damping materials like asphalt shingles, or dynamat, etc…
with these still crazy prices on things these days ive really been wondering what to build my next box out of. i fell in love with birch when i left mdf finally. the light weight and being in a vehicle it was gonna see moisture so birch was nice. but it never sounded quite right to me. i go for low bass and this is why i never liked my subs with birch. it loses the bottom end. birch and oak are the same price these days and i really think that set me on oak. it has a way better bottom end. the mdf was the best somehow but im not doing another one of those. this here is exactly why the high dollar oak cabinets existed back in the day as the primo speakers. they had a much better sound response and alot more force with early technology.
where was the accelerometer data? and would be nice to see a full comparison box between the extremes, worst performing wood with no bracing and no stuffing. then the mdf maybe at 3/4″ thick with bracing and stuffing, alos with aluminum foil with bitumen covering the inside box. it really helps with adding mass and damping. it is easy to fit 2 pounds of it.
Thank you for doing the test. Well I am ambivalent about your findings. I have performed similar tests like this one. With different subwoofers & the results were all over the place. Because everyone doesn’t make subwoofers the same way. Different subwoofers respond differently to different types of enclosure materials and thicknesses. With or without bracing or polyfill inside the enclosure. These types of tests are cool & informative but for me not ideal. I need to know how that subwoofer responds to stress in that enclosure. That is the real test, how it responds when it reaches its nominal recommended wattage or close to peak wattage. That subwoofer & the enclosure will let you know which is better when partially or fully stressed. It is true bracing matters & stuffing too but it becomes sometimes it is very specific to a woofer or subwoofer. In my experience ½, ⅝, & ¾ mdf have never let me down regardless of the application or enclosure size. Once the bracing is added the enclosure is really rigid. Then the polyfill or stuffing is to help with the fine tuning of the enclosure. Some manufacturers require a particular type of stuffing for optimal sound quality. I am a huge fan of passive radiators. They can be a lil fussy but in the long run the pros out weigh the cons. Especially if you have a woofer or subwoofer that you think it might bottom out!
Good article. Agree with the conclusions. I prefer matrix construction epoxy bonded plywood with additional damping treatment from either bituminous panels or this stuff (google soundservice & dedsheet-sound-damping-sheet – to avoid YouTube anti spam filters 😖). Veneered MDF always feels like cheating to me. I actually think poor cabinet damping (structural & acoustic) is why there is a following for open baffle speakers. Better to absorb the rear wave before it gets into the room IMHO…
this is great stuff. ive always been curious about this and wondered about speaker design and a possible correlation to guitar design and i have a theory: super dense back and sides (akin to ebony or african blackwood or mahogany) with a thin top that is braced on the back with scalloped braces (european or sitka spruce OR cedar for warmer mids/top end). edit: all that being said, my favorite speakers are tied between an old pair of chinese sharps and some auratone cubes (5c?) and am a big fan of ladder braced gibsons and guitars that sound dumb and tubby.
Zu Beginn des diy lautsprecherbaus gab es kein MDF in den frühen 80ern. Spanplatte! Massivholz in jeder Art war verpönt. Wegen der Eigenresonanzen. Multiplex gab es nur für PA. Eine gute Alternative war 2 verschieden dicke Platten mit unterschiedlichen Resonanzen zu verleihen. 19mm +13mm. Heraus kam ein wirklich brauchbares Resultat 👍👍🇩🇪
The tone wood argument in nearly everything has always been a massive contention with people when its honestly not percievable unless were talking Acoustic instruments. I come from the Electric Guitar Space and people have been fighting for 50 years about what wood there guitar bodies give them a WARMER or DARKER Tone when its been proven that your PICKUPS (their placement), STRINGS, NUT, an BRIDGE are 99% of where your initial tone comes from. It blows my mind people are at eachother throats over placebo
Finished my baltic birch tonewood speaker cabinet. Can’t wait to set this bad boy directly on the top of my desk without an iso pad, backed right up against the wall as tightly as possible in my untreated sheetrock room with oak flooring. Just got a new subwoofer too. Points straight at the floor and is 2 inches away from it right from the manufacturer like they all do for some reason.