fivelitermustang Posted April 21, 2003 Share Posted April 21, 2003 I currently have a Adire Tempest sitting here... I am almost done a 18"*18"*19" box sealed (about 3cu ft). It's pretty much a cube. Can I get away without bracing it since it's a cube? I plan on stuffing it with polyfill and all that... The amp that I should get tommorow (Tuesday) is an Adire AVA250. Quote Link to comment Share on other sites More sharing options...
cdsang Posted April 21, 2003 Share Posted April 21, 2003 Well, if you want My honest opion, then I would do it. If its just low levels all the time, you might not need it, but I belive when you push it, it will make a difference. If it were me, I would do it without a second thought. Hope this helps. CD Quote Link to comment Share on other sites More sharing options...
prodj101 Posted April 21, 2003 Share Posted April 21, 2003 I say brace it. Quote Link to comment Share on other sites More sharing options...
formica Posted April 22, 2003 Share Posted April 22, 2003 I remember reading an article about unbraced subs and the required "wall" thickness in order to do it somewhere online... unfortunately I don't have the link handy. Given the woofers displacement volume, the rigidity of the material used, and the maximum size of an unbraced length panel, you can calculate the required thickness to prevent the cabinet from resonating in the audible range. If I recall the general rule of thumbs for an average sub were along the line of ±10" to 12" unbraced dimension for ¾" MDF ... If using the bracing is impossible and you go with 18" I'd consider doubling your outside enclosure walls to 1-1/2" MDF. Quote Link to comment Share on other sites More sharing options...
hwatkins Posted April 22, 2003 Share Posted April 22, 2003 Bracing is one of those 'no lose' ideas. Even if you can get the results you want unbraced, bracing will not damage the sound. If your box is on the edge of needing bracing, as yours is, you will definitely not have to worry about whether you should have done it. There is a strong chance that bracing will improve the sound, or at least keep your box sounding good over time. Also, since this is interior stuff it doesn't fall into that meticulous carpentry category that the exterior requires. Plain old ugly scraps can usually do the trick. As always this is IMHO... Quote Link to comment Share on other sites More sharing options...
TheEAR Posted April 22, 2003 Share Posted April 22, 2003 Lets say it this way Bracing improves the structure of the cabinet,as braces will render the box more inert and stiff.And a speaker box should not vibrate or bend under the pressure created by the driver inside. A speaker/sub cabinet is NOT like a tall building that has to give in order to stand.The ideal speaker cabinet would have ZERO VIBRATIONS even at max playback level. I say brace the cabinet and cover the inside walls with acoustic absorbing material. Speakers designed like "musical instruments" are total and utter BS,they may reproduce the guitar and few instruments well but fail miserably on other material. Thiel,Wilson Audio,Goldmund best aproach to cabinet making AS INERT AS CAN BE.They use composite materials and even concrete baffles(Thiel)to almost eliminate vibrations.This however is very expensive and not too practical.The old and simple bracing is inexpensive and works great.Look at B&W Matrix series,B&W uses the matrix bracing here,many thinner braces interlock forming a near dead cabinet.Great stuff but not practical unless you own a CNC shop. Unless you have a sphere or cylinder cabinet bracing is a near must. Take two great examples One is the SOny WM40 "sub",built around a paper like cheapo trash can box and compare it to another sub using a 12" woofer,the Aerial SW12.The Aerial cabinet is only second to Wilson's Watch DOG and Krell MRS.Its as rigid as MDF cabinets get,braced like a tank.NO AUDIBLE BOX COLORATIONS CAN BE HEARD.And the two sound worlds apart,the Sony booms like a hollow garbage can and the Aerial is as clean as clean gets. BRACE the cabinet. Quote Link to comment Share on other sites More sharing options...
fivelitermustang Posted April 22, 2003 Author Share Posted April 22, 2003 Ok... so the answer is unanimous... brace it! Now how would I go about bracing it. Also to theEAR: What kind of acoustic material should I use and how would I apply it? Wouldn't it be a fire hazard with the back of the amplifier touching the sound deadening material. (I just got the AVA250 today, btw)... Quote Link to comment Share on other sites More sharing options...
formica Posted April 22, 2003 Share Posted April 22, 2003 The current trend seems to be: - filling with polyfill for sealed subwoofer (the kinda you find sold as stuffing at walmart) - lining the inside walls for a vented enclosure with either egg-crate foam or polyfill but not filling/stuffing the box I don't think either will cause a fire hazard as the hot elements of the sub amps are oriented towards the exterior for cooling. Quote Link to comment Share on other sites More sharing options...
TheEAR Posted April 22, 2003 Share Posted April 22, 2003 "- filling with polyfill for sealed subwoofer (the kinda you find sold as stuffing at walmart) - lining the inside walls for a vented enclosure with either egg-crate foam or polyfill but not filling/stuffing the box" Yes this is one good way to go I doubt very much the damping material would be a major hazard,if the amp get so hot as to start a fire your MDF(or any wood composite)would start to smoke.All quality amps must have overheating protection and shut down in case of malfuntion. I still would not place insulating material on the amp circuits(we all know the transistors heat most),sometimes other components malfunction and burn.Quality subs use sealed amps or have a smaller chamber for the amp(Aerial). Smaller subs with PR's dont need stuffing,for example the Sunfire subs are covered with a white substance(glue)inside.The amp almost sits on the huge magnet of the woofer. I chipped of a piece of what looks like a relay in my Sunfire Junior(still works fine).I open almost all I buy Quote Link to comment Share on other sites More sharing options...
fire pinch Posted April 25, 2003 Share Posted April 25, 2003 Mm this tread is very interesting... I planned to make a subwoofer this summer with the Adire Tumult driver. For sure, I will have to brace it considering the monster which house in the box. But... suppose that I want it sealed at first (I thought about a vented design but I prefer to try this later) and that you calculed a volume of 2 cubic ft for it. Do you take in consideration the braces for that volume??? This may be a stupid question but I will just begin for the first time to DIY this summer! P.S.: The Ears, I bet that you will find a new name for calling me in french! Quote Link to comment Share on other sites More sharing options...
formica Posted April 25, 2003 Share Posted April 25, 2003 You would have to add the volume of the braces to your calculated volume as well as the volume of the driver itself. If it were a vented box, my understanding is that you'd have to add the port's volume as well. Have you gotten on the Tumult waiting list? There seems to be quite a few a moaning going on at HTF from those who have been waiting for what seems forever.... but it promises to be a pretty impressive driver. Rob. Quote Link to comment Share on other sites More sharing options...
fire pinch Posted April 25, 2003 Share Posted April 25, 2003 formica, Nop, I didnt order the driver yet. I will order it in end-June or early July certainly. Im affraid of what you said for the waiting list... I just hope that as soon as I will order it, that Ill get the woofer at least in a week or a few. Be sure that Ill be proud to let everybody know how it perform against some subs as I know that not so much reviews has been revealed. I know that Im not the reference like TheEars because I didnt listen to all his subwoofers but I listened to quite some, some B&Ws, Energy, Klipsch, Paradigm and the one I have now, the Hsu VTF-3. I have a SPL meter so Ill show you as well some numbers You live in Montreal?? Nice to meet a second "Québécois" in this forum! Quote Link to comment Share on other sites More sharing options...
TheEAR Posted April 25, 2003 Share Posted April 25, 2003 Pincette de Feu, No Pincette de Feu should stay,no more inventive French names. Oh yes did you know they changed the name from French vanilla to Freedom vanilla...LOL And now the French Poodle became the Freedom Poodle!Talk about bastardising the world LOL Where is my Freedom toast? Quote Link to comment Share on other sites More sharing options...
formica Posted April 26, 2003 Share Posted April 26, 2003 I noticed you were in Quebec... but are you in the Montreal region too? I'm just asking, as wouldn't it be fun to setup a subwoofer shootout ?? I've pre-ordered a Stryke AV15 (shipping probably in July) and a JBL MPC200 pro amp (see my other posts in subwoofer section as well as the HTF) for an upcomming ported DIY sub. By late summer i'll have my Energy ES12 to compare to my new DIY Stryke AV15... but a VTF-3 would be more serious comparison... and don't even mention the Tumult All the subs would be measured in the same room so the resulting numbers would actually give a feeling how they compare in real life. Drop me a line if it intrigues you... Rob PS: There has been quite a bit of understandable whining over at the HTF in a thread called "Tumult Reviews" as the Tumult had a pre-order period around 6 months ago... most of the buyers are still waiting for their drivers. It's a new design, the initial demand seems to have been quite high, and the manufacturer ran into some initial fabrication problems... all this has angered quite a few Adire customers left waiting. I'm not sure how long it'll take to settle the backorders. Quote Link to comment Share on other sites More sharing options...
fire pinch Posted April 26, 2003 Share Posted April 26, 2003 LOOOOOOOOOOOOOOOOOOOLLLL!!!!!!!!! The_Ears, each time that you call me like that I almost blow my intestines!!!!!!!!! Oh well, I think that Im gonna replace my nickname on msn which was Firepinch and Im gonna write Pincette de Feu! LOOOOOOOLLLLL! Quote Link to comment Share on other sites More sharing options...
fire pinch Posted April 26, 2003 Share Posted April 26, 2003 Formica, Check your PM box, I messaged you Quote Link to comment Share on other sites More sharing options...
TheEAR Posted April 26, 2003 Share Posted April 26, 2003 Pincette de Feu, A subwoofer shootout! LOL I am not into deaf MAX SPL contests,its easy to spend $2000 US and build a sub with massive SPL capable of outblasting all my subs. If I ever feel I need house tearing SPL I will order a few BIG TC sounds 15" woofers and build a IB or sealed monster capable of brain and liver damage.So far SPL is a secondary,very secondary importance.Quality is paramount Quote Link to comment Share on other sites More sharing options...
fire pinch Posted April 26, 2003 Share Posted April 26, 2003 The Ears, This is not me but Formica who started that "subwoofer shootout", you refer to the wrong person here. I think that he didnt mean that we compete each others to know which sub, the tumult or his Stryke based subwoofer who will be the best performers. I think that he just wants to compare numbers by curiousity and to know how a Tumult and Stryke subwoofers performs. Well this will be just interesting and Im not the person who want to make the most powerfull sub and to have the most SPL on this planet... the Tumult woofer just interested me and Im just willing to build a subwoofer with this driver. I rarely play my music above 105 dB anyway ! I will say it right away, my main goal with that sub is to have a good enriching experience and to have fun, thats all! And to know someone who will make the sub pretty at the same time is just more fun! In brief, I see just this shootout (if we do one) interesting and positive. Well, for my side, I just had the intention to post numbers and SUBJECTIVE comments like a review. Quote Link to comment Share on other sites More sharing options...
formica Posted April 26, 2003 Share Posted April 26, 2003 Pincette de Feu is right about my intentions I too am not out to build a sub that'll hit record breaking SPL's (no house tearing SPL's )... But more of a "same room" comparison. Like I'm sure you (l'oreille, maintenant les oreilles) has discovered ... bass frequencies are very room dependant, especially in the rooms lowest audible resonant frequency range. So much so, that comparing 2 subs results / auditions performed in two different rooms reveals more about the rooms than about the subwoofers. I guess my intention is not much different than buying/borrowing several subs, trying them out and reselling those you liked least... which I'm sure you can relate to? If you're in the region, would you be interested? There is a lot of talk about DIY subwoofers and their capability of outperforming some commercial subs... and I'm curious about how much truth there is to this. The problem with many people's personal reviews of their home built sub is that they end up comparing two very different units... one which they have been disappointed with (ummm... can someone say KSW?) and their new hand made, with lots of passion, time, and research subwoofer... Do you see what I'm getting at? I'm thinking "Somewhat biased" When I set out to replace my subwoofer (which I find quite musical, but lacks extension and power) I became very intrigued about SVS and their obvious origins in DIY. Would I be able to build better for less money? I've been told YES, but I honestly don't know... I decided to try it anyways... and it'll be a learning experience into what makes a good sub. I've decided to build, what I think, is a conservative subwoofer: one AV15 in a ±20Hz tuned port 6ft3 enclosure and a 600W mono power amp into it (eventually a BFD to tune it). Once I'm done I'll have only the opportunity to compare 2 subs in the same room, time, and position, so the reference will be quite small... and be of limited use to others. Will it be more musical than a VTF? Will it go deeper than a RSW? Is the Tumult worth it's price difference? Is Smirnoff Ice better than Mike's Hard Lemonade? ahhh.... the great mysteries of the world... Later... Rob Quote Link to comment Share on other sites More sharing options...
jstanton8 Posted April 30, 2003 Share Posted April 30, 2003 Hey formica: Once I gets me a trusty rat shack spl meter I would be glad to give you some numbers for the AV-15 for comparison purposes. With only a miniscule 380 watt plate amp this bastard makes it difficult TO SEE STRAIGHT when listening to music. Whole damn field of vision is blurred. While watching TV simultaneously, the picture on the 'ol 32" Sony vibrates terribly. I cannot as of yet tell whether this inability to see straight is due to: a) the vibration of the TV itself by the subwoofer, or eyeball vibration and associated brain and optic nerve shaking I think it may be solely due to soundwave induced eyeball instablity. In any case, that AV-15 driver is one bad mofo. Quote Link to comment Share on other sites More sharing options...
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