Subwoofer Box Bracing is NONSENSE!

[@DIYAudioGuy]

Crushing subs with a Humvee: kzbin.info/www/bejne/aZ29eouwedicndksi=f9Je6ROXQuax3dhR Massive Subwoofers: bit.ly/4cxXhXi Unicorn Spit: amzn.to/4f7gYY1

[@confrontationnation4734]

THANKS A BUNCH for this vid. i was wondering just last night if i can change my subs from rear facing to upward facing without adding another brace!

[@rhkips]

I've built a LOT of boxes over the years, and the only time I've ever used a corner 45 was to alter airflow characteristics in a port, and it was in conjunction with a lot of other supporting tweaks. Now, as for panel resonances and bracing and whatnot... You are absolutely technically correct in the application you're demonstrating! A subwoofer enclosure needs different treatment than a full range box. Subs typically don't care about shelf braces, but in a full range enclosure, placement of a shelf brace has the ability to impact midbass and midrange performance by altering internal reflections and affecing standing wave characteristics. I've built a few tower speakers over the years that used "shelf tuning" to tweak peaks and valleys. Along the same lines, bracing and mass loading can become the same thing, just depending on how you approach it. I like using 2" dowel rods to tie front to back, top to bottom, offset within an enclosure. In this situation, you're not "dividing" the panel into individual constructive resonances, you're effectively mass-loading two panels. Install that same 2" dowel rod at a 45 degree angle between the front and bottom (or top) panel, and things start getting really crazy. Now you can introduce hardwood/solid wood enclosure materials and play with their natural resonance characteristics... Can you tell I have too much free time on my hands? LOL But again, this is all full-range application. Subs really don't care. They want somewhere nice and solid to sit and make their wub-wubs, and you're not going to drastically change the timbre and presence of a sub by fine-tuning panel resonance. Just build the box with meat where it counts, and put your time and effort into designing a box that matches your sub(s), space and desired output. :D

[@DIYAudioGuy]

I think that sums it up nicely, you said it better than I did. Simple and effective braces, ones. You can install quickly and easily. That's the way to go.

[@NORVAheelhook]

I was always told was the 45s were for the air flow to have less resistance…I’ve never have have heard it as a brace

[@spedracer55]

same here

[@SonyFoLife]

Came here to say this

[@mikeapplegate292]

Yup. Same. Also I’ve hear similar with fluid and gaseous systems.

[@BaddDukk]

There is no air 'flow' inside of an enclosure. The woofer pressurizes and rarifies the space equally in all directions. As Justin said, they only help cover up shit cuts.

[@SbassLaser]

I've definitely seen people argue that it adds strength. In either case, they don't do much of anything. I only use them inside the port if I have to add a corner to the port

[@mullinperformanceaudio5902]

I dont always 45 brace my corners, but when I do.......nothing, nothing happens. It makes me feel good tho and I can feel better about myself when im using thay box as a jackstand.

[@DIYAudioGuy]

Is the juice worth the squeeze?

[@jorgem50]

Love this video and topic and here's my take. I have two 15inch boxes built by my local box builder. The first one was built about a year ago and he used corner 45s plus bracing. The second one I told him I wanted it to be the same in specs however I told him not to worry about bracing or 45s and by eliminating those two he gave me a discount. I have the same subs on both boxes and they sound exactly the same to my ears. Yeah the one with bracing is obviously stronger but at the end of the day it didn't make a difference in the sound. BTW, I'm not using huge beefy subs, I'm running 4 skar 15s svr

[@DIYAudioGuy]

But four of them, that's a lot of cone area. I would call that a big build.

[@jorgem50]

@@DIYAudioGuy I have two subs per box

[@zarboaudioprojects1430]

The one exception I can think of for the corner 45 is when using large radius roundovers on the outside of the cabinet, Ive done that myself on a few builds... But for car-style sub boxes, yeah, the joints -- as long as they are solid -- should be strong enough for normal stuff. Like you said on bracing, were really trying to get panel resonance down... even just gluing a 5x5 inch piece of particle board or MDF slightly offset on a panel will help out with that. Love your videos sir! Youve got a great delivery!

[@DIYAudioGuy]

You are exactly right, you will need something in that corner if you slap on a massive round over.

[@1-Six-dee]

U should build this enclosure with no braces do a port score across the bandwidth from 25-75hz then add the braces and see how it affects the enclosure

[@DIYAudioGuy]

I need to do that. Do you think people would watch the video? I think I need to do two versions, one with low-power subs and one with some huge subwoofers.

[@kirankuttan]

People ​would absolutely watch that video 😁 @@DIYAudioGuy

[@jayweb702]

@@DIYAudioGuy Yes people would watch it because we like facts over fiction. We want to see the science and myths busted etc.

[@haydensmith9064]

Yess

[@APinTheAK]

I would absolutely watch. And yes! One with low power and one with huge. You that shit man. Thanks for all you do for the community and industry.

[@BlenderRookie]

Yes, I would like to see a test of the various different brace styles to test how it affects resonance. I suspect a combination of double thick walls and staggered braces would be the best. But I also suspect the difference between both together and either by themselves will not be that noticeable unless you are using huge subs and a lot of power.

[@natehaviland3244]

Battens are useful for prefab boxes. No need for the 45 though. 2x2 lumber will suffice. Way easier and you do absolutely want to do every corner in that case. All bracing can be done with the method you showed. Simple strips of plywood.

[@DIYAudioGuy]

Right, and that's so much easier than cutting corner 45s.

[@natehaviland3244]

@@DIYAudioGuy this is the main reason. No table saw, no need without these. Plus airflow really only matters inside the port, round ports offer a much better solution if that's an issue, less surface area per port area.

[@mikeunivers]

It is true that the bracing changes the resonance to a higher frequency which is good, because they are the ones that matter the least in a box for low frequencies, that is why in HI-FI speakers they are used to eliminate the resonance that can affect the low mids and mids🔈🔈🔈🔉🔉🔉🔉🔊🔊🔊🔊🔊🔊

[@CrystalClearSQL]

I honestly thought bracing was to reduce panel flex in the box... the baffle mostly. And a few dowels always seemed like the best go to. Didn't consider resonance, good stuff.

[@DIYAudioGuy]

Think about how much pressure it would take to get a piece of MDF to flex.

[@SbassLaser]

@@DIYAudioGuy Not as much as you'd think. At least, when you've got some beefy subs and a few kilowatts of power going to them, things will definitely flex! That's why it's common to use a double layer baffle.

[@intrepidpursuit]

100%. One of my favorite designs for boxes that are hidden away are a metal and well braced baffle with a lightweight molded enclosure behind. The air pressure change within a box is barely measurable even at high SPL and a little bit of flex in the box makes very effective damping. Any movement at all in the battle represents parasitic power loss that isn't making sound. I recognize that this type of balloon enclosure, as I call it, is not practical for the majority of applications. I make speakers for weird applications. Even in more traditional MDF enclosures I still like to use metal in the baffle when practical.

[@mrcornut]

I've never thought about offsetting braces 🤔

[@DIYAudioGuy]

Yep, you should stagger them at irregular intervals

[@manjulwalia1995]

I accidentally always to that because when it comes to bracing , I put the CNC cut brace anywhere inside enclosure ... also I have heard that it is recommended to place any sort of bracing or support at interval of 8 inches

[@fonkenful]

Irregular spacing of multiple interlocking braces (think B&W matrix) is not just for sub woofers. I found it very helpful to tightly nest a brace to the rear of bass driver’s magnet structure, leaving of course opening for those with ventilated pole plates. I’d frequently run a single vertically oriented member off centre, running the full length of the enclosure to couple 4 of the six panels of most rectangular enclosures, along with offset horizontal braces sub-dividing the side panels into multiple non identical sized areas to spread resonant energy over a broader spectrum of frequencies.

[@APinTheAK]

Don’t forget tho, if your using an aero port, you want to keep the diameter of the port distance away from any brace. Same with the rear subwoofer as well(I believe). Mr. Chuffington gon chufffff.

[@mpalmer3111]

I've been building speaker and sub boxes since 1988. Back then, no internet, so I checked out books from the local and school library. One thing that people often forget is that the boxes should not provide additional panel or standing wave resonances in the box because no box should really be a one note wonder. So, you aim to try to end up with differing dimensions in the height, width and length of all you panels and try to avoid simple ratios because panels will resonate at their harmonics also. So, one reason for bracing one panel but not another would be the original panel resonates at the original frequencies, but the second panel resonates 8/5 higher (or whatever the ratio) the idea being you want the box to not have any overlapping resonances - just as you mentioned. In the speaker books, any time you had a narrowing of the space, they recommended chamfering or adding a corner brace to reduce turbulence - chuffing in bass. This is why aeroports are also better than straight pipe ports if the port velocity is high. you can design a speaker with no internal bracing that has no overlapping resonances but it takes time and it might not fit in the back of a car or SUV well. Anyway you are spot on with the resonance discussion. Kudos to you sir.

[@DIYAudioGuy]

Right, you don't do all of this stuff to make the box stronger. You do all this stuff to make the box sound better.

[@derson754]

Would dowels placed at random places throughout the box help disrupt the resonances?

[@DIYAudioGuy]

@@derson754 Large diameter dowels work great.

[@derson754]

@@DIYAudioGuy if they aren’t for strength is large diameter even needed? If the goal is pure resonance disruption whatever is the smallest dowel that can get a screw in it placed in a bunch of random places would make the resonance frequency high enough it doesn’t matter. But also still relatively cheap. Or maybe even just some 1x1 boards not even rounded to save time

[@sandwich.entity3810]

Great tip about summing resonating panels, and making them slightly different sizes! Never thought about this but makes total sense.

[@DIYAudioGuy]

Glad it was helpful!

[@miket2120]

The only time I ever used corner 45s was in a transmission line speaker. I've seen window bracing in high end speakers and they definitely made the box "dead": they sounded and felt like you were hitting a concrete block. Shelf bracing in the most effective way, in terms of time and materials. Gluing tip I learned from a professional woodworker: don't starve the joint of glue (it should drip out when you fasten them together) and sprinkle a little sand along the glue line - just a couple of grains per inch is all you need. When your joint is pressed together, the sand digs into the wood and keeps the joint from slipping as you nail or screw the joint closed.

[@martinajenkins]

From my experience I found the best bracing is by using strips that are cut at 45 degrees at the ends. I don't brace across. I brace one side to the side perpendicular to it in more than one spot . If the speaker box is already built I tap on the wood and brace where the pitch of the tap is lowest. That's where the wood is going to vibrate the most. I do this around the whole speaker and place these 45 degrees braces on the spots I find. Of course the area where the speaker cut out is weak and will colour the sound . So I brace next to the hole and brace that to the opposite side. Tapping on the box will show where bracing is needed .

[@DIYAudioGuy]

This is the best comment. This is the way to do bracing.

[@mark63366]

Nailed it. Does it make a difference yes, can you hear the difference driving down the road at 60? No. Look into high end audiophile speaker cabinets. 45's in the corners are used for better response and bracing is used in big boxes to decrease resonance. However, the bracing used are many short pieces of wood placed from one panel to the next. Sometimes foam is added, and also dynamat could be used, but again you will never hear it in a car.

[@PShizzzle]

I love your logic bro!! Ppl preach to me that 45s are necessary BUT never 45 the entire box. 👨🏾‍🔬🔊

[@paulmingie3245]

I never do 45's I just glass the inside with resin to make smooth as possible and the resin helps with resonance.

[@dustinwatwood6101]

Im glad to you made this video, im not new to car audio but i am still learning about DIY custom enclosures, placing them in the port made since for air flow, but the inside i thought was for box flex, ( yes I learned that from the endless videos and articles at some point) figuring only practical in competition settings, not my daily. Thanks for clearing it up. There really is so many mixed opinions in this rabit hole but i love it😂

[@DIYAudioGuy]

Just to be clear, I am saying you don't need a brace. I show several cost effective and simple braces in the video.

[@davej3487]

I had an old set of Kenwood floor speakers that have 4 each 12 inch woofers, not subs. They had 2 4 inch mids and a HORN tweeter. 120 pounds each. They had NO bracing inside and just a 2 inch thick fiberglass batting stapled to the rear. The only bracing was the 4 cutouts were glued to the back baffle and Yes 3 inch wide corner braced. I cut the rear panel out and built cross braces with cut outs, used six 1 1/2 dowels front to rear and 2 left to right and added a 1/2 inch front baffle too glued to the original. The only 45 degree bracing I added was to the rear perimeter so i could glue a new back panel in. MASSIVE change for the good.

[@DIYAudioGuy]

Right, the box was strong enough when you started, it survived shipping and the woofers did not blow the box apart. But adding the bracing improved the sound quality.

[@dragan3290]

I'm glad I found this video because now I feel better. Pre drill mdf with pva and timber coarse screws. Caulk in sikaflex after assembly! Sit for 24 hours to get rid of fumes! Half fill with Dacron ( tontine) as specified by electronics engineer who always taught and gave me solutions to a problem. Always had a great sound for a good budget biuld. Only my 15 inch old Targa subwoofer I used 34 mm mdf.

[@thethingswedowithjoe7320]

Thank you for this video Justin! I'm getting ready to build 4 boxes starting tomorrow and learning this about braces will save me a lot of time!

[@DIYAudioGuy]

Some shelf bracing placed strategically should get the job done.

[@YellowSn0man]

The best way I've found to use shelf braces is diagonally. I only use them on larger spans and don't even attach the brace to the adjacent walls. I attached them with pocket screws on 12" centers just to apply pressure while the glue cures(keeping pressure on your glue joints while they cure is vital, plenty of videos on youtube showing that). Twenty years ago I used to overdue the internal bracing. These days I only brace on spans over 3sqft. I took the 3sqft rule from designing sheet metal equipment, which is much more prone to resonance. To the people gluing and caulking.....just use a polyurethane construction adhesive instead of wood glue. Lay down a large bead so that it squeezes out the edges. You glue and seal in one step. Not only that, but wood glue needs the two surfaces to contact each other to adhere, the construction adhesive can fill gaps and still have a strong joint.

[@DIYAudioGuy]

Right, simple and easy brace that gets the job done.

[@TheOffD]

Unicorn Spit pre-stain at 50% water dilution, 2 times and sand between... then apply a final coat. This gets depth into the grain and reduces streaking. Cover with lacquer/clear epoxy to make it POP, necessary otherwise it looks like chalk paint.

[@DIYAudioGuy]

I managed to improve it a bit, but it's not quite right.

[@SbassLaser]

what I do is spray water directly onto a brush with a spray bottle, then just dab a few drops of dye onto the brush, and brush it on. I did a few different methods in testing before I ever used the stuff on a project and that was the method that I got the best results with. I'll have to try your method some time and see how it looks. The clear coat is definitely necessary tho! I used a gloss spray on clear coat. I was afraid brushing anything on would make it smear. Do you brush your lacquer on? Oil based I'm assuming?

[@RecordnRtist]

I like the last series of videos posted a lot! The woofer cone displacement comparison video is really good. In the "Advanced Speaker Systems" book by Ray Alden, he discusses the golden ratio as it relates to cabinet dimensions panel resonance, but bracing is not heavily discussed. The comment section here is great, too. I like this video and just recently braced my last enclosure that has a Kicker 50th Anniversary Gold 10". I figured 400w RMS warranted its bracing even though it's a cube. lol

[@DIYAudioGuy]

The loudspeaker design cookbook by Vance Dickason talks about offsetting the brace and using a shelf brace -- works just as well as a "window" but far less effort.

[@RT668]

I never understood the need for corner “bracing” either. Nice video

[@DIYAudioGuy]

Thanks! 👍

[@HifiVega]

The 45’s are mostly an esthetic with the exception of the 45 in the port that I often use to maintain my port width. Often once these are built the point to point at the corner of a slot port will be a good amount larger than the desired port. I don’t think it makes a huge difference output wise, but I have noticed some inconsistency in sound when I have not done this.

[@DIYAudioGuy]

Exactly, the one in the port is needed. The rest are just for looks!

[@GMR_Works]

Great video! There is so many illogical misconceptions out there

[@killabee623]

About time, I always thought corner pieces was a waste and cube reduction. Reason some some brace the backwall only is they tend to believe that the back side of the woofer send pressure to that wall...

[@TRONMAGNUM2099]

I'm sure what you say is all true. I've always used a 2x4 as internal bracing. Then I used silicone on all the seams to make sure I had no air leaks.

[@DIYAudioGuy]

That gets the job done.

[@Bassotronics]

Be careful thus...there are some silicone types that actually peal off over time. Caulk is what I use to seal off. And even caulk comes in various types too.

[@YellowSn0man]

Just use construction adhesive instead of wood glue. You glue & seal in one step.

[@kjata77]

Years ago I started using a few cuts of 2x4 as braces (none in corners or seems) to "brace" my boxes. I've wondered about applying vibration (aka. "sound") deadening material to the outside of boxes. I've been a SQ guy for @30 years and a properly designed & built enclosure for the given driver is really what matters ('enclosures' can affect mid-bass also of course). This was another great video, I've never done 'window braces' or sub 'support braces'. Too much work for no proven returns.

[@DIYAudioGuy]

Right, is the juice worth the squeeze?

[@intrepidpursuit]

I often use a CNC to cut out sub boxes. In that case a window brace can help to shape the box during assembly and takes little extra effort. I agree though that the window brace is definitively not better for sound than a 2x4. The additional mass of the 2x4 and the ability to place it asymmetrically make it superior sonically.

[@DIYAudioGuy]

@@intrepidpursuit But the window brace looks cool on KZbin, so it must be better.

[@rawbasicrawbasic]

Thanks for putting this out there 👍

[@donalddluckerii3147]

The double panel resonance is only a factor if the panel still resonates once you've added the bracing. Yes panels will always resonate I understand but by stiffening the box by adding the bracing in the middle (or offset) You have done a great job of minimizing resonance overall. One other option is to install two or three dowels attaching the front and back and possibly even the top and bottoms. This does a fantastic job of minimizing panel resonances

[@DIYAudioGuy]

Yep, the goal is to eliminate the resonance.

[@intrepidpursuit]

No amount of stiffening can reduce resonance. Only damping can do that and stamping requires flexion. Stiffening can only change the frequency of the resonance. Pushing that resonance up higher in a subwoofer to get it as far away from the frequencies you are injecting as possible to avoid harmonics in or outside of your intended bandwidth can be useful. But bracing cannot reduce total resonance. A solid concrete block will still resonate.

[@lasse9118]

i have just made a small 27 liter, bookshelf subwoofer box for an Epique E150HE-44 with passive radiators. but in my rush to get it done i had forgotten to add any bracing at all. but now after watching this i can relax a little

[@DIYAudioGuy]

Just to be clear I am not saying that braces are not useful. There are just a bunch of myths floating around about what they actually do.

[@lasse9118]

The E150HE-44 is just 5.5" and the box is made of 25mm mdf. I will be very surprised if there is any vibration in the box😬

[@DIYAudioGuy]

@@lasse9118 awesome

[@AllboroLCD]

A braced vs braceless box video would be a great idea! Theres also stuff called "No Rez" I see offered by kit speaker company GR Research thats also apparently helpful.

[@ZeroResonancy]

This makes so much damn sense. Hope lots of ppl see this

[@DIYAudioGuy]

The frustrating part is people seem to think that I am saying that you don't need to brace the box. You do.

[@StatiXonfirE]

😂 this makes me feel so much better about never measuring where the braces go

[@JeffAdairKTM530]

braces are easy and cheap and should be used always. no benefit to not.

[@DIYAudioGuy]

Some braces are easy and cheap. Some are not. And there's no benefit to using something that provides no benefit, it's only cost.

[@brucermarino]

I generally agree with you. Offsetting braces has a long history. In your design, however, does not the port introduce asymmetry into the front and back panels as well as the top and bottom? Thanks!

[@DIYAudioGuy]

Yes, it does. One of many reasons I prefer slot ports.

[@jasongago9618]

I actually designed a box that has batons. Top, bottom and sides. It was for my Stereo Integrity sql-15. I even have the design on SketchUp. I would use MDF for the box and 1 1/8" marine grade 11 layer plywood with redwood core for the batons. Old growth made stuff.

[@esolo4751]

If you are considering comparing boxes with adding 45s, you would be able to do a 1/4 scale of any box design. You're testing airflow efficiency in a plenum. So you can save a ton of time and money in just keeping each comparable box a lot smaller.

[@deanedgx]

I offset my braces and use the golden ratio where practical. Cheers for another great video.

[@IzziedeD]

i've only ever thought of a corner 45° as useful for airflow in a folded or taperd (tl) ports, where maintaining the cross sectional area of the port is important for acurate tuning. as far as corner 45° for strength or resonance 🤷🏻‍♂️, for added corner rigidity, i cut numerous 3/4 x 3/4" sections, about 6" long and afix them along the inner corners on all sides, and some 2-3" wide braces from front to back or top to bottom. sometimes i make a 'stonehenge' looking arrangement of braces in a circle around the woofer hole.

[@ryanchappell5962]

Adding the bracing shifts the panel resonance to a higher frequency by effectively making the panels smaller. This can often times raise the resonance completely out of the range of the subwoofer or speaker or bringing it to a level where the resonance is very small because the mass of the panel doesn’t allow it to resonate much because there isn’t enough energy at that higher frequency to move it substantially.

[@DIYAudioGuy]

This is the way.

[@intrepidpursuit]

Harmonics are a thing. If you stack up your resonance too much you can make it ring no matter how far away it is from the frequency you are driving.

[@Patricks_Projects]

Harmonics my friend, harmonics. Small forces can take down big structures if they are in harmony with eachother at a destructive frequence.

[@DIYAudioGuy]

Another reason why you want to go with uneven spacing.

[@Patricks_Projects]

@@DIYAudioGuy yes, i never stated otherwise. My intention was that you can never brace to much.

[@intrepidpursuit]

No amount of bracing will reduce resonance, only move it. In structural engineering the solution to resonance is often in flexibility over rigidity. That is the definition of damping. If adding more bracing makes your spans more consistent in size then you are concentrating all of your resonance in one place. Harmonics mean that even if you have a subwoofer low passed at 80 hz box could ring at 2 khz if that is where your resonance has stacked up. Damping and breaking up frequency of resonance of the various box components are what will prevent an audible ring.

[@highgoals4204]

I've done my previous box using a shelf brace for some reason at the time I figured if i cut it into a C shape it could maximize the air value but still act as a brace.

[@nickstalhood5380]

This is something i was always curious about. Here's why, over the years I've had tons of both home an car audio speakers. In 90% of the home audio stuff ive owned never had any kind of bracing but i did notice that some of them actually used the cutouts from the main driver's an glued them directly on the back of the box behind the driver. I assumed it was for controlling resonance and strengthening the are behind the driver. If that is the case why isn't that done with car audio boxes? Why go through the extreme of all that extra bracing?

[@DIYAudioGuy]

Right, makes you start to think. What's this stuff all about? A lot of the times the bracing is left out to save on weight, that stuff has to be shipped halfway around the globe. Just to be clear, I'm not saying we don't need bracing, I'm just saying the box is strong enough.

[@tacka73]

6:45 great bracing but they will change your box tuning and also potentially change resonance of the subwoofers depending on the size and position and amount you install. I personally like the dowel method one top to bottom one front to back and one right to left. Also just caulk all joints instead of 45°

[@Undecid]

From what ive heard the 45's are for breaking up eventual standing waves inside the box, not for panel resonance or airflow. But if that's the case you're better off making a wedged box anyways.

[@CarAudioEnthusiasts]

the corner 45s, in my experience are more to add glue surfaces, but you are correct, they should be used on all corners, and from manufacturers they are. though they are usually short chunks that dont go the whole way. as for the rest of your video i agree 100%.

[@DIYAudioGuy]

Yes, they do give you more glue surface that is a good point. If you need it on one corner then you need it in all of them.

[@christaylor4283]

I need a box build can I get your number

[@HyPex808-2]

I’m new to building sub boxes but I have never used any braces. So far I have only built sealed boxes because I’m not willing to give up my trunk. Dual 10s or 12s so far no issues

[@20hztremor]

I remember in the 90's Kicker recommended 1x1 bracing on all inside corners

[@DIYAudioGuy]

If you look at their current owners manuals Kicker recommends a triangle shaped brace in the corners.

[@20hztremor]

@@DIYAudioGuy I have not seen current stuff though I'm still a Kicker fanboy. All my gear is mostly Cerwin Vega nowadays with some other great audio stuff. Enjoy your vids 👍

[@DISOPtv]

This guy out here spitn. But hard to refute logic, good video!

[@DIYAudioGuy]

Just trying to get people to think.

[@DISOPtv]

@@DIYAudioGuy Love it! I never thought about it as probably many others, it was just "the way to do it." Def appreciate you!

[@KuroDensetsu]

I was just looking for a video on bracing like a month ago. I was building a battery powered bluetooth speaker with two 10" Eminence pro neo drivers, compression driver+horn and a KABD-4100, and wanted it as light as possible, so I used 1/2 ply and braced the heck out of it with battons and triangle braces. This strategy seemed to pay off and panel resonance is fairly minimal, and the box is super light.

[@jamescrabtree4609]

I would like to see a test done to see if two separate boxes have more box rise than one single box with two woofers

[@SkittlesScott]

So you only have to brace enough to get the resonant of the box outside the bandwidth of the subs? As in above 120hz for most subwoofer applications?

[@sandwich.entity3810]

I think generally you want it more like an octave above your xover frequency ideally, so think 240hz instead of 120hz. This is because a speaker will still play sounds above the xover frequency, just quieter, therefore if you have resonances significantly increasing the volume at a certain frequency it can still be an issue even though its technically above the xover frequency. Hope that makes sense

[@jayinmi3706]

Joey at 12Vtools has actually shown boxes that he built where he did "corner 45's" on the horizontal surfaces as well, but him and maybe 1 other guy are the only ones I've seen do that.

[@DIYAudioGuy]

Cool! I will have to check that out

[@uome2k7]

The 45s are more for no hard corners to be there to create turbulance in the air flow. The panels perpendicular to the sub mount holes would be parallel to the air flow so the force works on them less than the walls that the air flow slams into. Think of how bass tubes perform. Some bracing is added just to support the weight of the sub since it is cantilevered by the screws on the front plate.

[@Azmodon]

I've never used window bracing or corner 45's... I mean, I've filleted corners using caulking just in case vibration cracked the adhesive or something, and if I needed to brace a long panel, I just use round dowels and glue / screw them in from both sides. Zero router work, perfectly smooth lol

[@marcos-ut7mq]

i personally use dowels to tie the panels together, works well and take s up very little displacement in the enclosure.

[@DIYAudioGuy]

I like dowel's because they are easy and effective. That is what I am trying to get at in the video. That window brace looks cool but it does not work much better than a few dowls plus it takes a ton of time.

[@soldjahboy]

Bass waves like to collect in the corners and travel UP (this is why horizontal 45's aren't used). Corner 45's are good for stopping standing wave formation in the corners of your enclosure. If you look up "bass traps" you will find the audio science behind bass and corners. Bass traps are used in full scale rooms inside of your house for example, but the logic still applies to a speaker box or your car.

[@DIYAudioGuy]

You're comparing a room to the inside of the subwoofer enclosure. A room is a much bigger space and more room for waves to propagate. Plus the idea of Base getting trapped in quarters and moving only upwards seems strange to me, what's going to stop it from moving side to side?

[@soldjahboy]

@@DIYAudioGuy Yep, but the same principle still applies though on far less of a scale. Not sure why it travels 'up' exactly, but that's what's described in the acoustic studies that I've read. I don't fully understand the mechanics of it myself as I'm not an acoustic engineer (I'm just interested in audio) but I guess people do this in the box to remove any potential, no matter how insignificant. In a room it makes a big difference, in a car maybe not so much... but if you're into SPL then every gain counts? :D

[@jvsyoutube3298]

yeah, rattled enought of pre-made boxes apart that didnt have braces and no screws to use them in my builds anyway. Also when doing 45's, i just feel that they make more sence for noise of airflow and less flow reducing for the port(s)..

[@Bassotronics]

Tube FTW! No bracing needed.. No resonance issues. 1/3rd the weight! woohoo! I'm sorry I keep bugging about that. I just have to bring it up. lol

[@DIYAudioGuy]

Yep.

[@johnhumphreys9732]

I never add bracing on my boxes! I put 1 45 in the corner of my port, I think it helps with air flow. I believe a sphere would be the perfect subwoofer enclosure! You should build that!

[@DIYAudioGuy]

A sphere is, in theory, the perfect speaker enclosure.

[@ScottGarrettDrums]

The corner 45 isn't for strength. It's a bass trap. The same thing is used in studios. All of those extra 90* angles you're adding with shelf bracing create standing waves that reverberate and start to create cancellation issues.

[@DIYAudioGuy]

Low frequency wavelengths are very long. 30 HZ is about 37 ft. So you're not going to get bass trapped in a corner. But let's see you're right. And you do get bass trapped in a corner. Why only put the treatment in the vertical corners and not the horizontal quarters as well?

[@Dinglezz]

Haha. I've still got an pair of speaker boxes I made about 25yrs ago, for 8 inch speakers. I made them with 18mm birch ply and 20mm bracing along all inside joins, and sealed internally with silicone 🤣

[@DIYAudioGuy]

All of the inside joints, not just some of them. If you need this for one joint you need it for all of them.

[@KnowName33]

Everything you have said is true However it applies to home audio where the box will be playing over 100hz and well into the vocal ranges but its a different story with a sub box thats playing 60 to 20hz And so cross bracing is best because box flex will effect low end distortion and spl

[@DIYAudioGuy]

My goal is to get people thinking about proper bracing. Do we really know what does or does not work?

[@303nitzubishi4]

Great topic, I agree with most of your theories. I think building a few different identical enclosures with different types and levels of bracing to prove them isn't really necessary, I'd wager they're all going to perform within a margin of error in real world scenarios with "daily driver" subs. Now if you were going to do this for some 2k+ watt SPL subs and send them to bigD so he can push them with some huge JP93 or other crazy high wattage then yes you might see varying results 😆

[@DIYAudioGuy]

Yes. As far as testing enclosures in a high power application, I mentioned that twice in the video. I even threw in some clips from slamology to hopefully Drive the point home.

[@strangebreed3832]

When i first used unicorn spit i didnt like it...but i painted my entire enclosure with wood glue to seal since i had no shellac and tried the spit again and it looks badass after you clear enamel it once or twice. Lol i used 3-4 colors diluted 50-50 with water to get more out of em and just slapped the box with both hands doing my best jerry lee lewis impression for a surprisingly neat colorful glittery camouflage looking result that changes depending on lighting and angle

[@DIYAudioGuy]

That sounds cool! And that really seems the best way to apply it. That stuff More like finger paint than stain.

[@z1berzerker]

I tend to use dimensional lumber for baffle reinforcement and making the enclosure more solid... my own style 😎 ✨

[@DIYAudioGuy]

And does anybody have any actual hard proof that your method doesn't work? I have not seen it.

[@z1berzerker]

@@DIYAudioGuy Right ✅ 90% of the time my enclosures sound decent 👌 Keep up the great videos 📹 👍

[@highgoals4204]

I kinda wish I'd done a full brace as you showed first. I find myself tightening screws on the back every few months because the back wall has 0 bracing. The back wall has two inch thick wool cotton attached to it to soak up the higher frequencies. My box is a two 12 box dual layer MDF inner layer pinewood outer layer. And dual tone dual ported

[@DIYAudioGuy]

You should not have to go back and re-tighten screws. Did you use wood glue or construction adhesive?

[@miguelamigo6030]

Testing corner bracing video would be interesting

[@guhhran8614]

Well, then i',ve been doin every Thing right in the last years. 45's only in the port and when i use only one brave i go with a Window bracing or every Single wall gets its own brave. Also a brace inside the port can be worth it, all depends on the size and Power of the enclosure. I also prefer mdf with better bracing over plywood

[@gerardvoughnfaust4167]

we put a brace following the shape of the plywood. like we place it along the length of the plywood or length wise. it is a 1 inch or 2 inch long cut depending on the length of the plywood. we dont want the box vibrating like a wood passive radiator

[@sppb32]

Since the panels are going to resonate regardless it's better to have them resonate at the subwoofer's frequency, if you add a brace, you break the panel in smaller partitions, they will most likely resonate at a much higher frequency than the subwoofer, i don't know how that will affect the sound.

[@DIYAudioGuy]

That is a good point. I have looked into how to calculate panel resonance. I have yet to figure out how to do the math.

[@SbassLaser]

How do you know they will resonate at the "subwoofer's frequency" (did you mean the tuning frequency?) before the bracing is added?

[@sppb32]

@@SbassLaser Yes, there's a chance that a bigger panel resonate at a lower frequency within the subwoofer range (just theory)

[@sppb32]

@@JasonWW2000 Maybe, or maybe a little flex has actually better dampening effect, allot going on inside an enclosure we don't know about, I've built a ton of them and the simplest ones are the ones that sounded better, i was always toll to "keep it simple " for better results.

[@chupamishuevos303]

now can you talk about longevity of the box. how to make it last longer before it starts coming apart.

[@chupamishuevos303]

@@JasonWW2000 the flexing of the woofers. i bought a nice rockford box it was made really good but now cuz of all the use it kinda came apart and unglued itself

[@WintedTindows1]

to my knowledge 45s help reduce reflections as well as improve flow in ports

[@dennis3004psp]

i have have two big panels left and right side connected with with supports if you knock on the box you can find them, a friend has smaler panels but my are more ridgid. my panels want to move both to the in/outside at the same time so. if you connect them togehter they cant, the travel is limited by the support, i think this will NOT work in the direction from the subwoofer movment but for 2 from 3 direction it will work

[@kenabi]

i wouldn't put a corner 45 in for strength, but in some cases, i might for breaking up or directing sound reflections. its probably going to be a limited use case thing where i'm actually seeing an issue that would require it. most boxes are fine without them.

[@dennis3004psp]

i guess 45s can help to brake up some standing waves in a qube enclosure, it can help to act like a diffiusion corner, but i think its a midwoofer problem not a subwoofer problem but they help change Resonat frequenzcy and this will help, so it is box dependend

[@olbluetundra881]

With larger enclosure I always use braces. Not only to help with flex but done properly it can also help with tuning. I've even used a brace for port area in a Sq build for a jl audio subs. Added some poly fill to help with port dampening and speed. Actually turned out better than I expected as far as Sq. Probably lost a little on the higher end. But this guy didn't build for spl.

[@DIYAudioGuy]

As the box gets bigger the need for bracing to dampen the enclosure increases.

[@markwentz8332]

Built my box with doubled 5/8ths (1.25" total) and a tripled baffle I didn't bother with any bracing as the Sundown Zv6 12" on 3kw (two SAZ anniversaries strapped) i'm running isn't gonna stress things that much IMO

[@cichrift9065]

Im with you but more surface aera is more surface area for glue so i add all i can for for less box movement but you are right there is no need for doing any of this unless your and audiophile!

[@DIYAudioGuy]

If you need more surface area for the glue then you would put the 45 in all of the corners, not just the vertical ones.

[@Satch_4_Hogs]

if you have the room, you can also angle your center bracing rather than making it perpendicular.

[@DIYAudioGuy]

Interesting idea.

[@firecloud77]

I've been experimenting with cylindrical enclosures. No bracing needed and they're MUCH lighter.

[@DIYAudioGuy]

Same pressure on all of the walls at the same time.

[@Clobercow1]

One must determine how loud or audible these resonances are to determine the value of removing them.

[@codybrownfield8222]

Ayyyyeeeeee so glad to see my box in a video lol

[@codybrownfield8222]

Also we have normally used massive 45’s for reducing airspace in the box. Example in my box I wanted 11 cubes of airspace after all displacement. With my port being close to 45” long and 15” in diameter my box is approaching 55” long and was way over air space spec. We added 45’s to reduce this.

[@DIYAudioGuy]

Which one was yours?

[@codybrownfield8222]

@@DIYAudioGuy first box, silver Jeep grand Cherokee with 2 18’s no wall.

[@DIYAudioGuy]

@@codybrownfield8222 Thanks for letting me film it!

[@robertoortiz85]

You might want to hit the books a little more… the 45* are so air flows smoother out to the port direction… and bracing is to make the box stronger doesn’t change frequency

[@DIYAudioGuy]

You need to watch the video again. You seem to have missed the point.

[@mmadd7]

99% of people who use corner 45's are using them to help prevent standing waves inside the box, no one is using them for actual bracing. If they are using them for bracing, they're only doing so because their buddy said they should. I've built boxes with the 45's and without, and my personal real world experience taught me that a box with the 45's plays a bit smoother than without.

[@DIYAudioGuy]

If corner 45s in the box preventing standing waves then you should put them on both the horizontal and vertical corners, every corner should have one. But nobody does that. If It actually works the way you believe it works then you would go ahead and take that one step forward and put that 45 in every single corner.

[@shaner.5]

I have a box that is made out of 10 ga. plate steel that has 2 15's, a divider, and has welded seems inside and out, no port, 1.6 cubic feet per sub, everyone told me it wouldn't work well it does work, it's the tightest hitting 15's, want to talk resonance ever had your heart want to change or skip a beat, this box can actually make your heart want to resonate with the beat, and when it does it is scary. I have always wanted an audiophile to measure all those Q's and Fs things I know nothing about and tell me it is wrong then have them sit and vibrate their opinion in the other direction, to prove it works and it sounds cleaner than any wood.

[@DIYAudioGuy]

Yeah, but you're using 10 gauge steel. That's pretty thick and heavy. Try that with 22 gauge sheet metal on most modern cars.

[@shaner.5]

@@DIYAudioGuy That would be like asking you to make a box out of wood paneling, strength is key, at the end of the day after all the wood bracing, double thick face, carpet... It would be a wash, and its waterproof just a bonus, I can tell you it is 179 lbs. what would your box weight with 2 standard 15's. If it was bolted down to the frame, it would turn your entire car into a bass shaker it not already. Can you tell me how much a 1' x 1' piece of 1" HDF weights. and I will figure it out now I am curious.

[@DIYAudioGuy]

@@shaner.5 I think a full sheet of MDF is just under 100 lbs.

[@shaner.5]

@@DIYAudioGuy so according to AI, a 1 inch sheet of high density fiber board because who uses medium density anymore I was blowing those mdf boxes apart back back in 1997. I was peeling boxes apart, aka my idea of metal, if you get an mdf to hold 145 psi, i would have bought one. high density, 1 inch 4 x 8 sheet weighs 165 pounds, 10 gauge 4x8 sheet weighs 205 pounds. So 10% in weight for an indestructible box, well thats kinda a no brainer. But as we all know, common sense, it ain’t so common anymore.

[@shaner.5]

In ohio, 1997 the world record was set with the 4 15’s, If I remember right it was a right around 170 DB. I hit 152.9 with 2 15’s in plate steel, I was on the podium with a $1000.00 subs and box, those guys had $15,000+systems 26+years later I reveal my secret weapon.

[@pineappleexpress8735]

You know, only place I have seen forty five bracing on all side of the box, It's usually a subwoofer enclosure meant for home audio. Not all of them come like this and some even the Front speakers will also have the forty five bracing on all sides. Just a fyi

[@jedpetersen3806]

I've been building speaker cabs for 30 years now. Part of that time I work for JBL, I assure you the corner brace 45° effectiveness is negligible to any frequency below 500Hz. The turbulence that people speak of is only applicable inside ports but if someone does something good and something bad and the copycats don't understand what the bad part is then it just gets propagated as gospel by the sheeple. Sound isn't about what looks good it's about what sounds good. Ok now let's get technical It's not enough to put a brace in just anywhere, even if you brace it well you may have just raised the panels resistant frequency to the next octave which still provides only a 50% reduction in cancellation. The intention is to raise the resonance frequency by several orders like 1/16 or 1/32. The waters start getting muddy from here of splitting hairs of audio file SQ or just rock hard for SPL. Hoffman will tell you ya can't have it all.

[@DIYAudioGuy]

Good to know!

[@jedpetersen3806]

@@DIYAudioGuy So just throwing this out there, if you don't mind the ridiculous amount of weight it'll add to a box. If you want an extremely low resonance subwoofer? Build a cabinet inside of another with a 3/4" gap in between the outside dimensions of the internal box and the inside dimensions of the outer box then suspend the inner box with 6 1"×1"× 3/4" rubber blocks placed in the center of each panel as long as they don't exceed 4 square feet and then fill the space between with fine sand. I hope you give this a try just for your own home theater! 😉 It's already gonna be bigger than ya want but go with it and make it big so just go with it 😁 Really enjoy your videos, your videos in my opinion are the best out there for DIY and information 👍

[@jasonnelson6624]

Isn't window bracing also used to prevent flexing? That's why or when I use them? Also isn't corner 45 done to smooth air flow? Honestly I don't do any bracing for my normal boxes. Only when I have multiple 75-100 pound subwoofers. Prefab boxes are the only ones ive blown apart or destroyed just from playing music.

[@intrepidpursuit]

Flex is only a concern on the baffle, though as you say, with heavy and powerful drivers it can be a real concern and a huge parasitic power loss. There is no air flow inside a box except near the port. The box is merely a volume of air that the driver pushes against. I don't know where this misconception comes from.

[@michaelfessenden8601]

Giving away secrets of the best builders' secrets 😮

[@scottybasham1020]

Thoughts on peel and stick deadening materials in lieu of bracing to prevent resonance?

[@donjaun540]

I like your thinking 🤔. 👍😎

[@DIYAudioGuy]

I am trying to figure out what works and what is actually worth the time and effort.

[@laszlosokolai2858]

Tell that to EAW. I have 16 LA400's EACH producing 140 DB at 1 kw. 12 inch drivers in each cab.

[@DIYAudioGuy]

Pretty sure I addressed the situations like that in the video, maybe you need to watch it again.

[@virgilnova6703]

I was taught 45 in corners eliminate dead space and increase efficiency. They are not so much for bracing. A Tuba doesn't have 90s .

[@DIYAudioGuy]

If so then you would put them in every corner of the box. If the wall to wall corner is a dead space then why is the bottom to back corner not a dead space?

[@bthemp01]

45's have been a waste of time in my spl testing. They should be tested, with a Termlab, prior to gluing in.