Building The Cheapest 21-inch Subwoofer In The World / Powered By A Desktop Amplifier

[@hatunhattu]

Your style of making speaker content is the style of videos that I enjoy and this build is awesome!

[@DIYhyfy]

Sweet! Thanks for watching!

[@colourbasscolourbassweapon2135]

@@DIYhyfy play some bass music on that thing

[@Toid]

Another great build! I guess it’s just means I need a 21 inch subwoofer for my desktop 😁

[@DIYhyfy]

Go for it!!

[@shipleyshipster]

Great video! Enjoyed watching the process. This is definitely WAY cheaper than buying a pre built 21" sub of the same performance and a typical amp. The only thing I would say for most people though is that we wont have a 21" cab from an old project laying around haha also once you add the paints, tapes, gaskets, mdf pieces, adhesive spray, felt, wood filler, wood glue, etc it would add quite a bit to the cost. Especially if you dont have any of that on hand.

[@3D1ofakind]

this is the content we need, awesome projects on the cheap. speaking of I'm tired of companies charging so much for high power amps! hopefully this will be a thing in the past within the next few years.

[@DIYhyfy]

I hope you're right!

[@vegapower454]

Cough cough SVS. lol

[@sudd3660]

Bought a Kill A Watt type of thing, and it is quite eye opening how loud i have to play to show some watts being used(over idle). I have two 10 inch subwoofer drivers, low efficiency and in sealed box with lots of gain added in dsp. 100 watt stereo power amp driving the subwoofers and it seems to be enough for all my needs and can push the drivers to it limits. so now i know how much watts is needed, and not surprised by this video, i bet it is amazing for the price and that tiny amp makes it all seem impossibly good :)

[@KunalVaidya]

Superb big driver build, Its amazing the way the 50W output is more than enough with high efficiency PA drivers

[@DIYhyfy]

It really is amazing how efficient big drivers can be!

[@TokeBoisen]

For music 50W is generally enough for 90% of drivers. You're only really gonna need more than that for something like a living room below 40 Hz

[@gregbarnes7548]

The mattress topper is doing the square root of f-all. Standing waves aren’t an issue in a subwoofer enclosure as the wavelengths are longer than any of your enclosure dimensions. Even if standing waves in a subwoofer enclosure were an issue it would still do nada. In order for “egg crate” to do anything the peak/trough would have to be minimum 1/6th of the depth of the wavelength you’re trying to diffuse.

[@StrangeBrewReviews]

Would of liked to see the sub done up in some thick 70s shag carpet.

[@Pentenfi]

I like these kind of budget projects out of curiosity so much! Really great video, thanks. I have used a similar amplifier like the one you have from Aiyima and it was just terrible, as the sub channel didn't produce any significant output even at full tilt. They may have set the gain too low internally.

[@DIYhyfy]

Yea maybe the gain was a problem. I've had a few of these small amps, and some are hit & miss. This one has no noise, no latency, and MORE than enough juice for mains & sub. Haven't ever had to turn up more than half tilt on sub or mains to get LOUD.

[@BackRDComputerScientist]

the problem most likley your power brick not gain i had this problem and figured out the power brick i was using didnt supply enough amps to draw full power from the amp so got a new brick and it works amazing now so that could be your problem

[@Pentenfi]

@@BackRDComputerScientist In this case I don't think it is the problem. The main channels work just fine, even if you give the bass a full tilt. But the sub channel is barely doing anything and even a few Watts would have been enough. I can't test anything else as I don't have it anymore, though. Recently bought a similar amp from Fosi Audio and it works great. It's the BT 30D Pro

[@curtissanjenko285]

Any idea what freq lows it can reach in room? ( 25 hz?) and I have used a Lepy mini amp 2.1 for years with basic speakers and smallish homemade sub, as my computer sound and to your point, quite amazing fir a $25 amp. No issues ….doesn’t have built in Bluetooth but using a $19 BT adapter from monoprice, all works great.

[@DIYhyfy]

I haven't measured the in room response just yet. It's definitely playing into the low 20s with authority.

[@CapraHiFi]

This just makes sense! and I love that amp.

[@DIYhyfy]

That amp is a powerhouse! No noise, decent built in dac, variable xover, tone controls?! Thanks for watching!

[@Jason01Adana]

can you make a sound check video and explane some details about it ?

[@djdawnpatrol]

Im looking to build a dual 21" subwoofer for my christian edm events - would these Dayton subs work? what amp would I need to really crank up the volume and shake the room? Ideally we would build two dual 21" subwoofer enclosures and have them side by side in front of the DJ ... what amps would be required to make sure they get powered correctly and what box enclosure should we build to make sure they slam? (our build could be dual 18"s if that makes more sense - similar to JBLsrx828sp)

[@nearchd504]

Can we replace that speaker cone with the cone which would have a rubber surround? Would this be beneficial in any way?

[@DIYhyfy]

You certainly could, but not to any benefit. It was designed with a certain amount of compliance in the suspension. Swapping things like that would change how the driver behaves, probably in a negative way.

[@nark7167]

Что? Поменять подвес на резиновый? Вы думаете просто так у профессиональных динамиков такой большой мощности ставят тканевые подвесы? Это сделано с целью жёстко ограничить ход динамика, чтобы он не порвался, резина с этим не справится

[@ant0091]

Wow,,,, U did a excellent job 4real 💯

[@DIYhyfy]

Thanks for watching!!

[@tylerolson5860]

Yep! Will be adding to my basement!

[@JayquanDeMarcusWashington]

What benefit does excursion actually have when compared to sensitivity or overall loudness? I'm trying to plan a build for a home DJ setup and I'm struggling to find a budget option to power either an 18in or 21in sub.

[@movieswithdaniel342]

What router and flush trim bit did you use?

[@mikecox7761]

Great build 👍🏻

[@billsmith5166]

Just a couple of other things, end grain won't adhere well at all with glue when applying bracing. I'd suggest an inexpensive pocket screw jig, they're really easy to use, and hold on tight. You might want to practice your finishing. It really can make DIY speakers look professional, and most DIYers don't think they can do it. The big difference is filler, multiple coats, sanding between each, then sanding down to 1,000 grit. Finish with a coat of compatible canned satin acrylic, one final 2,000 grit sanding and if everything looks OK, a final spray of satin clear. It will be an amazing finish, and make a world of difference. If you do it once, you'll do it on every future build. Great job on the sub, I'd love to hear it.

[@DIYhyfy]

Thanks for watching. Check out some other builds. I do lots of different finish work.

[@movieswithdaniel342]

What paints do you recommend?

[@billsmith5166]

@@movieswithdaniel342 Actually, unless you're set up with a sprayer, just regular high quality spray paint works well. Remember: sand, fill, sand, spray, sand, spray, sand, spray, sand and then clear coat. Gloss is a bit finicky but you can make it work well with a polishing compound. Make sure it's dry before you sand. It can take a while for a really nice finish, but it will look great. Dare I say, professional.

[@movieswithdaniel342]

@@billsmith5166Thx bro

[@danrussell9357]

I like the idea for the build. I think there is a lot of potential to repurpose pro audio equipment.

[@DIYhyfy]

You're definitely right. I'll definitely be using more in the future.

[@edwardasmannjr.2438]

I am enjoying your content! Let me suggest that you would notice a sonic improvement if you bypass Bluetooth? I switched from Bluetooth (which I thought sounded fine) to a DAC (the good measuring, highly regarded, and inexpensive S.M.S.L SU-1) using the HDMI ARC output from the TV, and was surprised by the very noticeable improvement in sound quality. I’m sure your setup sounds great but I believe there’s untapped potential yet to be realized. Keep up the good work!

[@DIYhyfy]

Yes, I have since gone with my separate dac, pre, power. There is of course a huge improvement. But as mentioned in the video, I does sound great. Especially at such a cheap price. Just to get a newbie into the hobby, they're great, amd affordable. Thanks for watching!

[@brucesamuelson7541]

Nice! I have the BT30D, upgraded to the pro, but the extra power came with distortion- returned it 😅

[@DIYhyfy]

Interesting! I haven't needed the extra overhead thankfully

[@ryanmichalski7420]

I saw that the sub was 1000 watts and the amp was 100 watts. I am new to speaker building, and from what I looked up I should match the RMS of the sub to the amp, and if possible get an amp with a little more watts. Could you help explain this to me better or provide a link/resource for better speaker amp compatibility

[@DIYhyfy]

The 1000 watts you see is a thermal limit. We can model the output in software. When we do this, we can see that very little power is needed to get loud. That said, the need for power increases drastically when getting louder. To run this at full volume, you would need more power. With that said, the 100 watts provides more than enough power to match mains for a smooth response, or even bump in the bass if desired.

[@ryanmichalski7420]

@@DIYhyfy thank you this helped me better understand the topic. 🔈

[@ChrisDIYerOklahoma]

Just sub'd in. Totally great design. I use those digital chip amps in my builds too.

[@DIYhyfy]

They're great for a ton of applications!

[@MrAzulikit]

What’s better? This or the 18” Ultimax. It would be for home theatre.

[@DIYhyfy]

I would have to say the ultimax is going to be better for HT. I say this mostly because of its excursion capabilities. The 21 certainly plays low, but not with the same spl as an Ulitmax. I say all of that semi subjectively, as I can't back it up with measurements right now.

[@MrAzulikit]

I guess it would depend if you’re comparing sealed verses ported as well.

[@BudgetBassHead]

Very creative I like it.

[@LucasFerreira-gx9yh]

can you measure the full range response please it seems that this sub may be capable for a good 3 way or low crossover 2 way

[@DIYhyfy]

Yea I could do that. I'll try to remember. I'll post it in the community tab at some point.

[@mcjonner]

Subscribed. Would have been nice to see a frequency response graph with using that amp? Can other cheap mono block Chinese amps be used or is there something specific about this one? I was wondering if a monoblock can be used with a diy sub and an avr? Thanks

[@DIYhyfy]

Hey yes you can use anything that will amplify a signal to drive a sub. Assuming the channel plays down to the 20s (some avrs dont). The only reason for using this amp is that it has its own dedicated channel low passed for a subwoofer. You could use a standard amp, and create your own low pass.

[@Enginemount]

Opening new avenues what common sense can do. Remarkably well build with utilization of every resources upto its last mile. Kudos 👏 brother. Respect from India.

[@joserivas1340]

Thank you, made me realize what i need to budget haha, great video!

[@DIYhyfy]

PAs are great for budget projects!

[@iikatinggangsengii2471]

true audio scene is abt preparing money and burn when time is correct

[@jessicaembers924]

What the size of that port, looks about a 3" slot? And how deep is it?

[@DIYhyfy]

Hi, I'd have to measure it, or look back at winISD model. I was around 3-4" x 17-20" or so. Tuning was 29hz or so if I recall

[@dadesakko]

Hello sir, i'm an engineer from italy, i'm on PA management field. One thing about this setup i need to say, the amp besides being really cheap, is the classic "mini house hifi amp", this means, probably have really really small control on a 21" pro driver, that can results in various problematic situation that can damage the driver, pro driver need to have a lot of power reseve, that's why PA amplifier are so expensive. Keep anyway in mind that a 21" pro driver is built to be driven from atleast 2kw RMS amplifier, but it can easily get damaged from a 100w no reserve amp peak/square. I'd suggest onestly something more PRO related, maybe china/cheap products with more complex DSP and FIR, they became a lot more affordable nowadays.

[@DIYhyfy]

Interesting, are you saying it needs more rms capabilities? I'm not generally running it very hard at all. The driver is only 1K watts rms, and didn't model well with that much power in the enclosure if I remember correctly. I may be missing something you are saying though

[@dadesakko]

@@DIYhyfy Sure, enclosure is not tuned to get the XMAX, but the thing is, if u get a transient on a track or something that makes the amp peak or lose the power reserve ( that at this point is really low, as amplifier dimensions say) the peaking of the amplifier can easily fry the coil of that woofer, since ur running it low probably it won't happen, but usually with driver that have this kind of RMS rating, ur most likely safe with an amplifier with atleast 1kw lets say. Consider in pro audio, we usually dimension amplifier at 2x RMS rating of a trasducer, exactly to not fall into the "out of control" situation. The only one apreciable thing that it gives u this way, is that its resonance frequency is most likely giving u higher efficiency down to 30/40hz, but also large pro trasducers have lack of sensibility if compared to smaller one. At the end of the day probably it was better to get a subwoofer 15" tuned really low, saving a lot of money (they're cheaper then 15" mid/bass speaker) compared to the 21, and invest a bit more on an amplifier, this way u can tune an EQ on the woofer for a linear stable response let's say from 32 to 60, that is most likely what u need in HI-FI. I saw u building the other speakers with also pro driver, the cross point is a crucial decision. If u want to also pubblish something intresting about having cheap HIFI i can give u some tips about things aviable in USA that are crazy underrated, i also usually buy strange DSP's from ship demolishing and things like this. One last thing about trasducers, if u really want to try build something insane, B&C and 18Sound in italy and BMS in germany, provide insane Hi-fi speakers plan, we built one for an installation with a berilium driver (4015BE), that was astonishing, with a custom ADAC 384khz, mini paraflex long excursion 8" subs and overall a cheap product compared to most blasonated HiFi brand, also we got Sonus Faber techicians working with us.

[@hans4me2]

@@dadesakko 21" subs are often much more efficient than 15" subs.

[@dadesakko]

@@hans4me2 ??? intresting information, it makes a lot of sense that more moving mass lead to more efficiency. If u have no clue about phisics works stfu please, don't give misinformation.

[@diymaster1121]

What kind of primer are you using for mdf ? I can build a decent looking box but i never know how to finish mdf properly.

[@DIYhyfy]

This was a kilz primer. I've used it on several builds, and it works fine enough. There is a product called sanding sealer. I would look into those before this stuff. But ultimately it's hard to go wrong. There are many ways to seal MDF.

[@diymaster1121]

@DIYhyfy Thanks for the suggestions.

[@JayquanDeMarcusWashington]

Also, the sub itself says it's rated for 1000w RMS, I've read (countless times) that it's worse to underpower a speaker than overpower it, how is giving 1/20th it's rated power okay for it?

[@DIYhyfy]

Hi, this is a myth. There is absolutely nothing wrong with running a driver with low power. In fact, the majority of the time, a driver is being used well below it's rated power.

[@JayquanDeMarcusWashington]

@@DIYhyfy That's a good point. Thanks for the reply! Been loving the videos!

[@MrMichaelEsser]

Great build maaaaaaaan!!! Are you still using your audience 212?

[@DIYhyfy]

I sure am. They won't be going anywhere anytime soon

[@lucienpellerin]

Great project althow one thing is bugging me is you use wood screw to mount your speaker. A better way is nuts and bolts.The bolt is called T nut bolt. It looks like a washer with spikes. The center hole accepts the screw,the spikes are used to did in the wood so they stay put while your fixing your driver to the box.The T nut is placed over you pre-drilled screw hole inside the box,it is fix in place with a C clamp.The C clamp pushes the spikes inside the wood,it is then secured to the box so you can then installe your diriver.If you ever need to remouve it,it will not damage your box as wood screw would. Bye. Lucien.

[@TyronePreslyAcosta]

No sample sound? I really want to hear it

[@DIYhyfy]

Unfortunately it's really difficult to record low frequencies.

[@iikatinggangsengii2471]

the sound kind of reminiscing me to smth but i dont remember

[@iggynub]

That cute lining won't offer any damping. Damping the sub would come from bracing to add rigidity and move any resonance into frequencies the kilohertz range, which the sub doesn't excel at - or with some CLD where a constraining layer attempts to resist resonance, like in car audio. At best, it at the extreme minimums made the apparent size larger, lowering the Q of the sub. Nice build though.

[@DIYhyfy]

You've conflated panel resonance with standing waves.

[@DiegoRodriguez-vd2sr]

Soundtest?

[@DIYhyfy]

Unfortunately it is very difficult to capture bass with most mics

[@PATRICEBAUDER]

Bonjour de la France........ bonne idée de partir avec un caisson de médiocre qualité et de l'améliorer ------ mais il faut beaucoup d'outillage, de la place pour travailler et beaucoup de courage......... ceci dit bravo pour le travail, par contre la peinture blanche granitée de finition va beaucoup prendre la poussière, dommage, avec une peinture lisse et mat, cela aurait été beaucoup mieux je pense

[@miknord5493]

Send me the link of the subwoofer!

[@DIYhyfy]

She's in the description above. Parts Express, Dayton PSS555-8

[@TheronCulpp]

How much port area?

[@DIYhyfy]

I'd have to go back and look at the numbers. Short answer: a lot!

[@wizard44]

so rad! love the video.

[@DIYhyfy]

Thanks for watching!

[@nickstalhood5380]

Dude i think this is the first vid of yours I've seen an i5 was awesome! What do you think that sub could total? Id like to get a set for my home theater setup. Id probably do some plate amplifiers. Also what size enclosures are recommended?

[@DIYhyfy]

Hey, thanks for watching! In terms of volume 6-7ft³ for vented. This is tuned around 35hz if I remember correctly. It will put out the lows with ease. Not sure what you meant by total, but if price, they're around $300 or less each.

[@billsmith5166]

Just wondering, why not buy a good used AV receiver instead of your amp choice?

[@DIYhyfy]

AV recievers won't drive a subwoofer. This will do mains, and subwoofer with lots of headroom.

[@billsmith5166]

@@DIYhyfy Dang. I completely didn't think of that. Sorry.

[@paulcsaszar5824]

That things gonna hit like a freight train

[@altops4490]

I have this amp, and it isn't as good as a decent stereo receiver, or the Ayima pro. I bought a used Nakamichi ta3a 80 x2 stasis amped unit for 80. And insemountibly better than a pocket amp.

[@Stan_the_Belgian]

You always get what you pay for, ultra low frequencies eat power, that's just how it is

[@SKITYSTUDIOS]

Nice

[@danieldeluzio8674]

Man. I need some enclosures for my 21s badly. You near NY? Lol

[@DIYhyfy]

Lol not even close

[@phazer131]

Check out gsg audio design brother

[@enrigimeno]

Wow 🎉

[@cynthiacox5170]

nice cat ;)

[@mholt76]

Just asking here… why go this route with a small amp? My FB market-place has tons of older higher end receivers: Onkyo, Sony, Denon, Yamaha ,Marantz for between $25-$100. Look hard enough and you find one with built-in BT, if not you can add an external BT adapter on it for cheap.

[@DIYhyfy]

A reciever won't fit in my entertainment center. I did even try removing feet from one. This is to demonstrate the potential of low power, small units, controlling large, high efficiency systems

[@ricardolopezgutierrez1989]

Saludos de Mexico amigos

[@extremenorthkomirepublic5923]

сделал также, только сабвуфер 2х12"

[@Loverboy_Bernice1977]

Thanks Bro. I'll try the fosi audio amp.

[@BLAFF420]

I need a 24" 😅

[@DIYhyfy]

Me too!

[@MikeHewitt]

next time try Dupli color spray on bedliner. Its in an aerosol can and sprays out a beautiful even texture.

[@AlexBass_Official]

I mean that is a woofer not a subwoofer 🤓☝️

[@DIYhyfy]

It's definitely a subwoofer

[@AlexBass_Official]

It looks mote like a woofer

[@RobertBoston-n4d]

@@AlexBass_Official You're right it does look like a woofer, but if its getting down in the 20s...

[@larrygaines7462]

Sub amp needs a large amount of power 100 watts rms at least for a 21in.

[@DIYhyfy]

I think my spouse would divorce me if I sent 100 watts to it, sadly.

[@drdubya3403]

Excellent build but imo, that truck bed doesn't look right. To each their own though.

[@DIYhyfy]

Yea I do somewhat regret using it. May redo it in an automotive finish in the future.

[@DearSX]

I'm going to build it and sell it at loss, then I will have built the cheapest 21-inch subwoofer in the world!

[@joshholden8561]

Fs of 27 htz what ? This looks like a woofer not a sub woofer

[@DIYhyfy]

This is most definitely a subwoofer. TS parameters tell us what a driver is. Not the appearance. I can assure you this will produce the lowest of low frequencies, with authority.

[@joshholden8561]

@@DIYhyfy yeah just doesn't look like it with such a small motor but specs seem nice.

[@geoffreymills9932]

I have no opinion about something I didn't hear

[@DIYhyfy]

Tough to record bass!