Misconceptions on Speaker Design

[@Gersberms]

On sound deadening: indeed both the box (let's just call it that) and the air space inside need to be as dead as can be, or else your speaker IS the instrument. Concrete speakers are being made, but rare. The one pair I heard stole the show (heard them at a HiFi show that I was at). It was a small enclosure (1 cuft or less) with a huge weighted passive radiator on the back, and curved sides. It wasn't just concrete but terrazzo, absolutely beautiful.

[@Elliott-Designs]

Just to go on off what Justin was saying at 10:20, the reason tuning a port is different to letting the panels resonate, is because panel resonance isn't easily predictable like port design, and doesn't necessarily resonate in phase. Think of how we try to avoid port resonances, if we let the panels resonate it's like letting port resonance come through but to a far greater extreme

[@blakebrockhaus347]

Hopping on this, it isn't just that panel resonance is hard to model, it also tends to occur in the lower mids. Which makes vocals, guitars, and most other instruments sound wrong. You generally wouldn't want to port a speaker at 500 hz (for many many reasons) because it'll screw up the midrange tonality

[@Thomas..Anderson]

2:30 Do we want a speaker cabinet to be inert or to resonate? 11:20 Bracing 23:00 Material 32:40 Speaker design. TMM topology. A complex topic. Things to consider, driver size, driver dispersion, driver separation, X-over type, X-over frequency. cabinet size, shape … 41:10 Good bass? 3-way or separate subwoofer. A thing to consider: Several subwoofers placed in different places in the room can help with standing nodes. With DSP even funkier things are possible. 48:58 Constrained layer damping 58:08 Electrolytic capacitors I think plywood is better material than MDF. For the same thickness plywood is stiffer and damps vibration better. Or in other words same speaker can be built with thinner and lighter panels. Fiberglass (or even carbon fiber) are useful for wonky shapes i.e. horns and waveguides. Both materials can be very stiff but also resonate so they needs damping in the form of constrained layer damping. 32:30 Why does the brace touches the magnet? The guy called Newton said that for every action there is a reaction. So if a voice coil (and thus cone) is pushed forward with some force, than the polepiece and magnet (and whole driver basket) are pushed rearward with the same force. If the basket is not infinitely stiff there will be some vibration and this is the idea behind bracing the magnet. But bare in mind that front baffle is structurally weak as it is a flat panel with large holes. Bracing the magnet in this way inevitably braces the front baffle to which a driver is rigidly attached.

[@EVnewbie]

Subwoofers were invented in 1968 by Infinity to solve the problems with peaks/nulls in small rooms. You might get good imaging of full range speakers in once place but suffer from peaks/nulls across a broad area of space. This eliminates making a compromise for speaker postioning and also prevents excessive heating of the woofer voice coil. Done! I use plywood, thinner birch for smaller speakers or thick ply, heavily braced for subwoofers. Bracing is key so I go with ply because it don't turn into snot if it gets wet or split the cabinet when it bounces off the floor. MDF is easy to machine but the dust is murder. Your choice! 2.5 ways I tend to use for larger drivers as a baffle step. It is also good to use for horizontal center channels if you are very hieight limited. To get "MTM" right, look up the concept by the guy that designed the first one--Joseph D'Appolito--he explains the purpose and it should be vertical. Lay any speaker on it's side, then things go crazy because our ears are on the sides of our head. I use poly because it lasts longer because I hate replacing leaky caps. As far as sound goes, that can be tested with scopes and other measurements--done! I build speakers that don't cross below 300 Hz so I just suck it up. If you want to save money, build 4 ohm speakers to cut the size down. Since my time is not worthless, I tend towards thinking of the cost compared to my time/effort and total cost. The price of wood makes poly cap prices seem more reasonable! Good video--as always, it depends.

[@AndreasLarzon]

KEF uses electrolytic capacitors in their crossovers on the R series. Since high values of capacitors tend to be very expensive, they build up certain parts in the crossover where they use "audio grade" capacitors that correspond to about 10% of the desired value and fill the rest with electrolytes. This can be read in their "White paper" for the speaker series.

[@djfirestormx]

and sadly it is blatantly obvious and shreads your ears, assuming you can hear accuratly. also sadly a large portion of people "who can hear good" ... quotes are scarcasm, claim there is no difference. something that gets really muddled by quality capacitors vs measurements usually gets injected by people who simply are cheap and don't like the price or people who have never heard the difference or even tried it...or belong to group A that have bad hearing they think is good...kinda like the crazy ones on american idol that freak out when the judge calls them bad and they think they are celine dion

[@AndreasLarzon]

There is a Swedish speaker manufacturer "Rauna" that produces concrete speakers. Rauna was founded in Sweden at the beginning of 1982 by Bo Hansson, Lennart Bergstedt and Olle Neckman. They have been around for a long time and, if I remember correctly, were also previously called Opus.

[@navinadv]

@Andreas Larzon I know Rauna! We had a pair of Balder! They were heavy. Made of concrete and were a MTM using 2 woofers and a tweeter. I am surprised someone else knows Rauna.

[@AndreasLarzon]

@@navinadv I became aware of them in the late 90s when I visited a speaker element manufacturer in Bureå, a small town near where I lived. They were called Sinus and were used in the Rauna (as I recall were named Opus) speakers at the time. Of course, my interest in this was rekindled when I studied acoustics and speaker development at the University of Luleå, located in northern Sweden, in 1999. Rauna still exists today and you can buy a model of these in a Swedish shop called "HIFI KIT". Last time I saw the speakers was a week or so ago when I visited the store to invest in a record player. An interesting note is that on the product page it says the following "If you choose to pick up your speakers in our store at St. Eriksgatan 124 in Stockholm, you get a SEK 1,000 discount per pair of speakers." One can interpret that as the store prefers not to send these speakers by mail :D

[@navinadv]

@@AndreasLarzon I live in India so buying and shipping them to India might not be as easy as it would be for a Swede.

[@SianaGearz]

I already knew the answer :D That successful designs lean on the inert box - resonant air - but there are some exceptions that deviate somewhat more or less deliberately. And i can't for the life of me find it but i think there was a Visaton study 1986-ish that found MDF to be pretty much the best material; though it did have a number of other vaguely interesting findings that invite further exploration, which is why i would like to recover it someday. Of course the easiest way would be to ask Visaton, they're said to be pretty friendly, but of course i haven't done that. Someone is asking about concrete - of course that Visaton study had that covered as well, but i don't remember what the conclusion was. I want to say that concrete itself needed a ridiculous amount of material, that something like glass-bitumen-glass sandwich performed better, but since it's been about 20 years since i've read that, i'm not sure i remember right! I'm not convinced i want to be near home improvement store bitumen for the first few years of its life, but i'm sure there's less terrible stuff out there. Plywood was deemed usable but wasn't really performing that well, they needed a larger thickness of plywood until they reached MDF's performance. But that was a box test - i suppose it can perform differently and better as a brace material. As to shaping the response, of course you do that, but Justin says "what if i make a tone stand out"... then by all reason you have probably ruined one piece of music in dozens or hundreds, and it ought to be someone's favourite, unfortunately. You can't expect all music to always sound perfect, but you do probably want to play around with your engineering compromises such that you maximise the number that sound and feel right, sound pleasant, which favours neutral designs. I go to expos and every time i hear a bunch of nice speakers but also loads of gimmick speakers which impress with something but just aren't general purpose listening tools. Making a shitty speaker sound good by choosing program material is easy! Oh, something to keep in mind is that parasitic properties of different capacitors are fairly different, due to larger size, polys can develop a good bit of extra inductance, though i don't expect this to necessarily bite you with the common topologies.

[@iowaudioreviews]

What about the Dayton .01uf poly caps your suppose to parallel with electrolytic to improve their performance? Is that a thing or is PartsExpress and Dayton Audio miss-leading people?

[@bjtaudio]

Another trick with the cabinet, is if quality plywood is used it, you will get a stiffer stronger box, less resonance of the box walls, but good bracing and the shape is key. Do not make cabinet walls thick as they tend to store energy. There is lots of free software to make you're own speakers such as REW for measurement, XSIM for crossover design, FPGraphTracer to get data from curves into XSIM, also u will need Photoshop to edit curves, to get FPGraphTracer to see the lines. Best of luck.

[@The-Sound-Guy]

A person has so many other things to worry about over box material, mdf is great. Bracing is good for all enclosures and to be fair port resonance is maybe more important but you must brace. Guys at the china factory I setup a test run between 2 entry level speaker systems 1 braced and 2 non braced on 2 lines. We ran dats and rew umik mics on each line as a Qc pass for both, the debate is non existing bracing has way way more tighter tolerances and thats on a chip board mass production line. Folks unfortunately confuse rigid vs damped. Our 15mm birch is 12 layers rigid as hell but its hard to justify the price but the cost of material can over shoot the cost of components. Nice vid guys

[@Elliott-Designs]

Increased rigidity gets the resonance frequency of the panels away from the resonance frequency of the air within the box, it means the panels couple much less and therefore effectively are dampened from increased rigidity. Whilst it is true materials have damping properties, rigidity also plays an important part in how sound is transferred (or even amplified, even if the phase is absolutely ridiculous from it). 👍

[@YOLOgamer-yq8yf]

I like my speakers to resonate, I like the sound it produces on the different genres I listen to!

[@NeilBlanchard]

The brace touching the magnet structure would damp resonances in the driver frame. Several comments about the bass - a separate subwoofer(s) has significant phase issues because they are at a different distances from the listener. So, to have "good" bass i.e. that has coherence with the music. And as Brian Steele knows - a transmission line speaker can get fantastic bass from a medium sized 2-way speaker.

[@rickbutcher3459]

12cuft box 3/4 mdf double motor board. 23x8.5 port. Braced. And insulated.. with a jbl 2245 18in. Tuned to 20hz. Just something I decided to build after watching your shows. Now changing the woofer. So I can really put the power to it. HT

[@Toid]

Sounds like an excellent build! You should show it off on the forum www.toidsdiyaudio.com/forums

[@Obsfucation]

In reality , you simply built the Lorr Kramer/Gregg Timbers/JBL subwoofer using the 2245H as detailed in the Audio Magazine article from August 1983. The primary focus of the article was on the eight cubic foot version that was sold by JBL as the B460. The twelve cubic foot version was described as overkill but, that didn’t stop young, foolish guys like myself from making one. It was a decent, high output design, especially for the time. Your efforts are commendable but, not new or unique. Please give credit to the originators above.

[@michaelfessenden8601]

When I started to play as a kid with speakers as a kid, most books would say 10:46 wood to use would be the ones the instruments were made of. Then, as intelligent math was invented and tests were discovered . So instrument amplified instruments used wood to make them lighter and used the lightes instrument wood. And music was recorded with that, so we grew up listing too is what we think that's what sounds good. MDF was discovered to resonate least with no color. Ad you're 100% correct on bracing 18:46 these are the secrets won contests with q or imaging , and db

[@NeilBlanchard]

Mineral wool is used as firestopping in buildings; with balloon framing for example. Jute is a natural fiber. And there is actual (sheep's) wool insulation.

[@iowaudioreviews]

MDF is the best wood material for building speakers because its the most consistent in strength and density per square inch. Anything made from natural wood such as wood boards or plywood is compromised by natural imperfections that can cause density and strength to very throughout the board. Now weather this is audible after appropriate bracing... probably not. Bit the main reason most speaker manufacturers including high end use MDF is consistency and when engineering about anything its much easier to get repeatable results when things are consistent. They build 100,000 sets of speakers they want them all to perform very similar.

[@sentezle1090]

The corner bracing is good. Just more mass and the air flow won't get jambed in the corners. There is air motion in the cabinet as ports attest to. I do like the idea of treating all corners. Though that much bracing should to be figured into design parameters,

[@bjtaudio]

I found a well made multi driver hi-fi speaker does not need a sub, with 4 or more 6'" mid woofers, bass is very powerful indeed. Also will not need any bass and treble boosting. I also found a well made passive crossover, can work so well you don't need an active crossover system for home hi-fi.

[@jimthvac100]

I think this is one of the best video's you two made together so far, good stuff.

[@Toid]

Thank you!

[@robertmedina3195]

@@Toid is that bot yours asking to direct message? I'm kind of a KZbin noob and don't even know how to directly message anyways.

[@Toid]

@@robertmedina3195 if anyone is ever asking you to directly message them, it’s not me. There are scams going around that try to replicate a persons name to scam you. It usually will have the word telegram in it.

[@onebylandtwoifbysearunifby5475]

MDF resonates severely. It rings like a bell at 60Hz and other frequencies. People saying MDF doesn't resonate are repeating something they heard someone else say, and never bothered to measure or verify. MDF is cheap. MDF is consistent (doesn't warp much). That's why manufactures use it, period. It also resonates all over the place.

[@josephsaucedo8691]

Some of the best sounding powered subs and high end sub boxes have bracing there are some sub that are so heavy they have to brace the sub or the basket on the sub will end up braking because of the wight of the magnet. Svs16 for example.🎶✌️👌👍💯

[@haknys]

When the highest end studio monitor manufacturer went to make a (2,2 KW active) high end hifi speaker, the used aluminium walls, and filled it with sand. Around the elements, they used honeycomb aluminium (from airplanes) for ekstra strenght. Much more complex manufacturing, but *much* better than wood. They even split the speaker into two parts, seperated by sand bags. Best sound I have ever heard…by a mile. Including Wilson, JBL, Focal Utopia etc. ☺️ Not DIY friendly, and very expensive.

[@shodan6401]

The reason no one uses natural hardwood is because solid hardwoods have resonate frequencies, the same thing that can make a violin sound amazing. Plywood, MDF and HDF eliminate resonances because the grain is not all facing the same direction. Two layers of plywood with a thin (very, very thin) layer of damping material sandwiched in between, like a painted layer of liquid rubber, can be more rigid and more inert than MDF.

[@goodwinml]

Could you please do a Klipsch LaScalla clone build? These were and still are awesome speakers. I would love to see your expertise putting a clone together that sound as good or better but for many $$$$ less.

[@naturalverities]

I love what my Lascala bass bins do for my listening experience. Their summed virtual 8 square feet of radiating area puts out amazing dynamic midbass and lower midrange up to 700 Hz. They need and greatly benefit from parametric EQ and cabinet bracing.

[@goodwinml]

@@naturalverities , back in the mid 80’s I was stationed in Great Britain with the USAF. I was looking at Klipsch Hersey’s, LaScalla’s and Cornwall’s. I almost went LaScalla but eventually got Bose 901 series IV’s. ALL of my stereo electronics were rack mount. I bought an old military electronics bay at a junkyard for about 10 pounds, about $12 at the time. It was standard 19” rack mounts with sides and doors. Not as deep as todays server racks though. I had Teac X1000R reel to reel mounted at the top of rack. Below that was just about every dbx piece I could use and buy. Amp, preamp and parametric eq were SAE. The Bose eq I even made a rack mount panel for it. The rack was around 7’ tall. I had around $2000 in my setup all in 1984 overseas military prices. When I got back to the states in ‘85 I priced up everything with stateside civilian prices and it came to around $8000. I still have my 901’s though. Bose replaced my series IV’s WITH series VI’sin the mid 90’s because of bad speaker material they used in the series I, II, III and IV’s. All it cost me was $500 to upgrade to the VI’s. Today I use my 901’s over at my 40x55 shop. The 901 hang from the ceiling in the back corners of the shop, power comes from 2 professional amps set fro bridge mono at 1000 watts each. Preamp is just a rack mount Dj 3 channel mixer. I have a Bluetooth module hooked up so any phone can play music, plus my pc is going through stereo. Omg Metallica sounds awesome in there! I want to maybe try to make some lascalla’s soon. There is one guy that did a 8 parts series on KZbin building lascalla cabinets. They looked sweet. I have everything I could find over the last 10 years on lascalla’s for plans. I have a .pdf file from original klipsch drawings with dimensions. One day I’ll get a pair made. I love this channel though. He does great reproductions of quality speakers. I hope he tackles lascalla’s sometime.

[@naturalverities]

@@goodwinml Fun stuff. I was once tasked with designing supports for Bose 801 pro speakers to allow them to be erected in the shallow space behind commercial cinema screens by a single person. Had the problem licked but the project was cancelled by Bose. When you make your LaScala bins, do keep in mind that they sound good up to 700-800hz. Broadens the selection of mid horns significantly. Mine are gigantic EV white whale HR9040s with 22lb compression drivers, sound magnificent. JBL-esque ring slot tweeters, 18" pro cinema sub, all DSP multi-amped (HIGHLY recommended). All for about $600. Cheers!

[@goodwinml]

@@naturalverities awesome, thanks!!

[@The-Sound-Guy]

Re the stand alone sub, I believe purpose is really to obtain + 10dB above the mains to follow "that hearing curve" and well another debate I guess would to lower non linear distortion at high excursions levels on the mains on a smaller woofer. Idk 😅 a stand alone sub can be moved around to help fight the room

[@Elliott-Designs]

That +10dB is a THX specification for LFE content reproduction. Otherwise how loud the subbass range is compared to the rest is preference. Harman found people tend to like the bass somewhere between 0-10dB louder than the main. Typically +6dB. But this is different to LFE content specifically

[@AwesomeSauceShow]

When you calculate the volume of the woofer enclosure, do you consider the volume that the bracing displaces and add the displaced volume to the enclosure, so you get to the exactly calculated volume? I hope my question is not too convoluted.

[@1rewd133]

Yes.

[@robertmedina3195]

To say a 10% change isn't significant is ridiculous. Polyfill does work. How well it works depends on how poorly the enclosure was designed in terms of size. I tried it with some cheap BIC FH6 speakers and they went from poor bass response to pretty good. If your enclosure is made properly you won't see as much benefit if at all.

[@leo11877]

Are dovels enough for bracing pre-made speakers with poor bracing?

[@Toid]

Dowels are a great option. It’s nice if you can connect all 4 sides, which is harder with dowels, but definitely much easier to implement. You could also cut some straight pieces out of some MDF and glue them either direction while also gluing them together..

[@bjtaudio]

Got some ideas for you. d'Appalito vertical MTM speaker designs do not work as driver cancel each other above and below tweeter vertical axis. Yes 3 way is best or next best 2.5 way. A few tricks, Place tweeter at top not in the middle, flush mount and time a-line the drivers. This matters. use 4 or more 6~6.5" mid woofers, where the top mid woofer is as close to the tweeter as possible, and the others just do bass up to a few hundred hertz. For less AM distortion of mid and treble of top mid woofer roll it off at 80 Hz. Put top mid woofer in a separate chamber. The bottom woofers can be almost anything except keeping all the same drivers makes crossover a bit easier. Lots of Smaller drivers work better than one or 2 big woofers in most cases. Bass drivers do not need to be in a vertical line, But keep tweeter and mid in center vertical line, as its radiation pattern works better in most cases. Do not attempt to use multiple mid-ranges and tweeters as they cancel each other. Better to use a mid-woofer for mid-range rather than a tiny 3"mid-range driver because then it means your woofer needs to be crossover higher say 800Hz and performance of the large driver cone is worse for mids plus you can only use one woofer or go to a 4 way and its getting over complex. My test prove multi 6" drivers working at 500~800Hz and up start to cancel. Oh midwoofer/tweeter crossover freq/ wavelength must be lower longer than the spacing between drivers and effective cone diameter of the mid woofer. 15-30 Degrees Off-axis horizontal response matters.

[@Toid]

You should check out my speaker the rule breaker.

[@attainableaudio4533]

For concrete... And 4 it rings, so you'll need to apply some dampening material to the walls. Just because it's stuff down not mean it's inert as far as sound goes

[@scottalbright2783]

An interesting speaker that I still use is the Polk LSI9. This utilizes the offset tweeter between the mids and is ported anteriorly with 2 small ports probably to limit box width. It is a lovely speaker that I leave the covers off of. They recommended the offset tweeters to be medially placed. Do you think that makes a difference in speaker design?

[@rikardekvall3433]

The ultimate DIY speaker? Can you design a 2-way speaker with an Arylic Up2Stream amp 2.0 V4 WiFi and Bluetooth 5.0 Stereo Amplifier Board in each speaker. With SW, you control the treble and woofer instead of a passive crossover. The L channel on the tweeter and the R channel on the woofer. Possible? With the 2.1 model, you can connect a subwoofer to each speaker or 3-way.

[@NeilBlanchard]

I think that there is something to having braces be placed asymmetrically on a panel - say at 2/5ths / 3/5ths on the longest dimension; rather than at the halfway point. This "splits" the new higher resonances so they are at different frequencies. You both cover this, actually, as I am watching. I want to also mention transmission line speakers - I think that since one end is open, the air pressure (so to speak) is lower, and so the pressure on the panels is lower, and so then it will have much lower displacement. I think that the closed end of the TL does need a brace.

[@Elliott-Designs]

Firstly, I wouldn't worry about splitting resonances, as you stiffen the enclosure it just resonates less overall, and the further it gets away from the cabinet tuning frequency the better this becomes. Not only that but higher frequencies are very often easier to absorb with acoustic material. As for the transmission line comment, it very much depends on the type of transmission line

[@NeilBlanchard]

@@Elliott-Designs If you put the brace at the halfway point, then each half is going to resonate (at a lower level) at the same frequency - about 2X the unbraced panel. So, their new resonance will sum together. Whereas if you go to the 2/5ths - 3/5ths position for the brace, then you get two different higher frequencies - and they do not have any common modes. So the new higher frequencies are not going to sum up. In a TL, you need to use acoustic damping to fine tune the fundamental frequency. As it happens though, all the polyfil needs to be in the closed end and right behind the woofer. Another nice benefit of a TL is that the internal baffles act as braces, *and* they are asymmetrical.

[@timealchemist7508]

Guitar cabinets are not HiFi sources. They are selected based upon the tone that the musician is looking for. Large cabinets are usually better for recordings. But no one wants to haul 4x4 ft speaker cabs for a small room gig.

[@Toid]

Great point. One is designed to create sound and one is designed to recreate sound. THe one that is designed to recreate, the box should not be resonate.

[@ronaldbrandt8037]

I do think that a subwoofer crossed over below 80 Hz dont need braces. There is no frequency in that range that if the panel is made of good quality MDF of adaquate thickness, you won't be able to hear any panel resonance. Full range speakers probably need bracing as those resonances will fall in the range of hearing where our ears are sensitive to the resonance. Bare in mind, some manufacturers have engineered the cabinet resonances to compliment the drivers response characteristics & may sound worse without the cabinet resonance though those are probably few & far between as it takes good talent to do that effectively. Now days drivers are often pretty well controlled in thier output asuming good low or non resonant cabinet design.

[@1rewd133]

I was here to find out why the B&W 801d in the thumbnail were a "you can't do that" and never found it. So, my question. If I had a 15" woofer with a given volume in a typical "monkey coffin" box and then place it in another box of identical volume but instead shaped as the B&W 801 D, would there be any appreciable difference in sound or performance?

[@sonusancti]

Musical instruments are designed to make sound according to its purpose whereas a speaker is made to reproduce recorded music as faithfully as possible. Their designs cannot correlate. Any box will resonate at a certain frequency. The challenge for speaker design is to move this frequency outside it's designated response. Make sense? The question I want to ask is, are boxless open baffle designs superior to box speakers? If yes, why don't we see more of them?

[@ElCidPhysics90]

Tuning is simply allowing more or less of what was recorded to be played.

[@Bluecrabsandsushi]

thoughts on foil backed dynamat on the inside of mdf? or at the least, spraying with rubberized soundblock undercoat? also, Corian, not granite

[@Elliott-Designs]

Typically these things have to be tested for effectiveness, and these tests can be rather cumbersome unfortunately. If you have the means to do it, and you want to, then go ahead. Otherwise stick to tried and tested well braced MDF until someone comes out with some new research 👍

[@luisbugel5495]

Hi, I have got a problem, maybe you guys can help me I built my first DIY speaker not too long ago. (GRS Speaker, just wanted to get started) I have pleasantly surprised with the bass response. (Around 27 Liter ported enclosure, tuned to 58hz f3) Now I wanted to add a second speaker. I reused two old bookshelf speaker chassis from my basement. I removed the old speakers and put a new (second) front baffle on it. (glued it on top) I checked the tuning on WinIsd beforehand. It should be 60Hz in a 22,5 Liter ported enclosure. Problem is, that now I have no bass whatsoever. What can be the problem? Is it possible that the Speaker loses energy when it does not directly sit over the previous speaker cutout from the older box? Thanks in advance.

[@Toid]

Why don’t you ask this on the forum at www. Toidsdiyaudio.com/forums this way you can have pictures and we can see exactly what’s going on.

[@gregkramer5588]

Back to the Monkey Coffins. I am listening to this on a pair of VMPS Tower IIr. The bass is fine :-) Great computer speakers!

[@shodan6401]

No. Justin is incorrect. Assuming that you are aiming for the design to produce a flat, in-phase frequency response, adding a port is solely in pursuit of extending the bass response - not to color the sound. Best practices should be to chase a flat response. If you want to intentionally color the sound, that's what tone controls and equalizers are for. But if your starting point is out of whack, how would anyone know what to change if they wanted the best representation of the original recording? If it would even be possible?

[@jayweb702]

Seriously? Simple answer no debate... If your box resonates, you can't control that resonance. But you can control the port dimensions to achieve the desired tuning. because if a box begins to resonate at a certain frequency that's only going to cause distortion. You don't want distortion in your speaker cabinets.

[@Pentenfi]

I always though bracing was important for subs but then I looked at Ground Zero's website where they show some do's and don'ts about box design and for ported enclosures, they recommend no bracing as this might cause additional turbulences that would cause audible airflow and lower SPL output. What is your opinion on that?

[@craigenputtock]

Interesting! Looking forward to someone who knows about this.

[@Elliott-Designs]

Absolute rubbish, the air in a port will be turbulent anyways unless you're playing at a whisper and your speaker has no basket and is at the end of a long tube not inside a cabinet. Vented loudspeakers are based on pressure differential physics, not waves physics (well, there's limited stuff you can do with wave physics for port placement to reduce port resonances, but nonetheless). Sounds like they're talking rubbish to me. Concept is sound if the sub was already in an idea system, but it isn't. Just don't have any bracing too close to the port entrance. At least the diameter of the port away from it (just like you wouldn't shove your port up against a wall)

[@Toid]

It sounds like they are hoping that the resonance of the box increases the SPL by resonating at a certain frequency. Which, if you’re going for SPL, might be beneficial, but definitely would not sound good. also, your box wouldn’t last nearly as long. In general, this is a poor idea..

[@Elliott-Designs]

@@Toid reducing rigidity of a box may get more output from the panels (of which is usually not useful whatsoever), but the crazy thing is, is that it would actually reduce output of the port!

[@attainableaudio4533]

Yeah tmm to me is fine as long as the xo is low enough to minimize vertical lobbing, learn not from just theory by building and testing.

[@BPatel-cx7js]

Does anyone know Brian's website? (The data on bracing)

[@Toid]

This is his site: www.diysubwoofers.org/

[@jaygron8303]

fun fact...they use formaldehyde in MDF

[@Rob1972Gem]

What every single KZbin expert speaker maker never mentions is every single speaker that is produced by a mainstream manufacturer and a small maybe one man, DIY speaker builder. They are all tuned crafted to reproduce the sound in a particular way to that speaker designer and companies will, everybody and every speaker, manufacturer and designer will have a slightly different idea of what they think sounds good. The secret is find out what speaker designers/manufacturers, make speakers that match the type of music you generally like listening to example, being, you wouldn’t buy a speaker from a mainstream manufacturer that is well known for making speakers for reproducing contemporary rock metal 80s nineties/music and then if your individual preference at home would be classical not going to work also all the way round you would not buy a speaker that is primarily designed and sold on the merits of being excellent for classical music if you like, heavy metal rock music There’s always too much rubbish spoken on this subject keeping in mind 99% of people buy a speaker a day like the sound of and they can’t afford and don’t start barking all about this rubbish about you could take them home and try it on a trial. No I don’t know where that bullshit happens, maybe in one or two shops if you’re their favourite customer, but on average you do not get to take stuff home and try it you buy it or leave it you don’t get to buy it change your mind and take it back

[@onebylandtwoifbysearunifby5475]

"Rockwool" and other mineral wool is steel slag.

[@gropping8008]

You could have started over and reintroduced. Damn

[@michaelfessenden8601]

Noooooo

[@rainier939]

Toid I know you don't do vertical off axes response but it does in fact matter so please read up on the subject with the research of Floyde Tool. So choices in tmm, mtm, tmw, etc. do matter!

[@Toid]

I do vertical off-axis measurements as well as horizontal. I don’t think anyone saying that there’s not a difference in the designs, but that there are very valid reasons in which designers do each of the designs. And with smaller woofers TMM is perfectly acceptable.

[@rainier939]

@@Toid With smaller drivers the problem is smaller that's true but the distance between the tweeter and the lower woofer with a 5" driver is still 10" or more. Thats the same distance as a 18" woofer 2 way. You just cant crossover that low with a dome tweeter. This is my problem with MTM and TMM designs in general.

[@Toid]

@@rainier939 I think one thing that you’re missing is that since the two speakers are acting as one the center to center spacing is the middle of the two drivers. This makes it realistically very easy to crossover very similar to a two way with the 10 inch woofer. I might not be explaining it well enough, but there’s a really good right up here that you can read about. Just look down at Jeff Bagby’s explanation on why he chose a TMM for his solstice that Parts Express sells. techtalk.parts-express.com/forum/tech-talk-forum/64889-isn-t-a-tmm-supposed-to-be-2-5-way

[@michaelfessenden8601]

Canceling waves

[@misterdecibel]

Sorry to be one of those internet smartass know it alls, but please, it's "damping" not "dampening"?