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DIY bluetooth speaker

I am making a speaker out of pvc pipe now. Its quite a lot of hassle, have to cut, then put into oven to straighten some part of it, having trouble fitting all the parts, etc. I am wondering of some easier to work with materials.

What about styrodur. Its like styrofoam but its more dense and it cuts really nice with a knife with barely any parts flying around. What would it be sound wise ? What about speaker made from cardboard ? And i could then mix wood glue and water and just add newspaper over it to make it really hard.

So to sum it up:

- styrodur (sense styrofoam)
- cardboard

How will it compare soundwise to pvc pipe ? Are those materials suitable to make a speaker or i better search for better material ?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Just try anything you like, and see what YOU find you like best, the whole point of such a small speaker is it's too small to give any decent bass, so a poorly designed (or simply guessed) enclosure could give you the sound you want.
 
Well i plan to do that, having fun building things is what its all about. But still i was just wondering if anyone has tried it and if its a yes yes or a no no :)
Btw, as mentioned the biggest problem so far i have is enclosure. And i found an interesting webpage that sells water pipes and air pipes and stuff. And well, i found a pvc square pipe. Which would be perfect and its quite cheap. I might order some and try. And ofcourse i will post results here :)
 

audioguru

Well-Known Member
Most Helpful Member
Nigel, have you heard a small but expensive portable JBL or Bose speaker? Their loudness and bass output are unbelievable.
Sentinel tried using a cheap little Logitech woofer and said it sounds good but is not available by itself.
I also have a cheap fairly small sound system that sounds good with enough bass.
 
It is actualy quite amazing how well that little 4" woofer from logitech works. I cannot explain it. The enclosure as u saw is not tiny but its really not big. I didnt add any special things, just connected it. And that woofer really packs a punch. I guess its because its made to be woofer speaker and to only produce bass. One of my friend said about my speaker .. "if you ask me, your speaker has a better bass then JBL extreme 2. And added: i never had JBL shaking me when i sat on this bench (speakers are always on the bench where we sit)". This woofer shakes so much that speaker is actualy moving when it plays. Logitech sheet states 9W for woofer. Now i dont know if that means speaker is 9W or amplifier is 9W, but driving this woofer at 100% through 2x25W amp barely distorts, actualy 30/50 visaton distorts more. I dont know how speaker can handle this, its 4 ohm while visaton is 8 ohm.

I actualy found some ppl with that speaker system, at least 2 so far so i will buy them and experiment more. And please mind 1 thing. If i put my speaker on a graph and compare it to JBL ... mine would lose, wouldnt even be a contest. But playing for drunk ppl who talk loud, it does the job and considering it costs about 10 times less then comparable JBL, it is not 10 times less good. And i found my friends are not really audiophiles, they care much about bass but dont care bout the quality. As long as it is shaking you and u feel bass in your bones, they are happy.

I was wondering, maybe i could do a test, play that recording that goes through all frequencies and record it and then make a graph from the recording. But i dont know if my mobile phones microphone will be able to handle the low frequencies
 
What would be the best way to test how passive radiators affect my speaker ? If i install them into a speaker and cover them with hand. Should there be less bass, that is, if they even work ? Sadly i dont have microphone with which i could sense bass.
 

audioguru

Well-Known Member
Most Helpful Member
My speakers do not move me or move their enclosures when playing. The ported ones produce puffs of air vibrations from their ports.
I have a brand new 18" sub-woofer rated at 900W that I have never used. I bought it on-sale at the PRO Audio manufacturer I worked for and the finished enclosures had two of them and shook the entire demo room when playing loudly.

I have never played with a passive radiator. If it is stiff enough not to vibrate when you hold it with your hand then I guess you can hear if it increases or reduces some bass sounds.
 
Ok, i ordered many many speakers, some from ali and ebay, some from 2.1 systems, some from tv systems, also ordered passive radiators. I also found a cheap pvc pipe which is square instead of being round. It is going to make testing and speaker making a lot easier, a lot less unnecesary cutting. I am really looking forward to getting all the gear and getting started.

On some other page they said that i should just buy cheap 2.1 systems to get the speakers i need cause i wont find them elsewhere. Which is unfortunate but ppl are selling cheap 2.1 systems for 5-10 bucks which is just fine. It is still funny though, ebay and ali basicaly have every spare part you need. It is amazing that they dont have some spare parts for cheap 2.1 systems in the form of speakes. Or maybe they do and i just cant find them.

Anyway fun times ahead. I really enjoy making new things and learning along as i go. Right now i would like to make a few cheap speakers with decent bass (like the one i have) and then sell them to my friends. I have to keep costs very low though, otherwise i will actualy be losing money instead of making small profit to pay for future speakers i make. And it is quite hard cause bluetooth speakers nowadays are so cheap.
 

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audioguru

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Most Helpful Member
But to make the sounds of deep bass frequencies you want, the speakers must have detailed spec's so that you can select a matching passive radiator and enclosure for them. The cheap Chinese speakers have no detailed spec's.
There is a foreign surplus electronics store in my city that sells cheap but high quality speakers that I can feel the weight, thump the cone to hear the resonant frequency, see how far the cone can move and feel the stiffness of the cone. That is a little better than buying something that has no spec's.
 
I know but i really have no other option. All the 4" speakers i found that have decent bass and excursion, they have to low sensitivity, which means i would have to add 4 times the number of batteries and 4 times stronger amp to get decent volume out of them. And like you said, those woofers from 2.1 systems that i will get have no specs so i am left with trial and error. I am still amazed how i actualy got my speaker to sound good. I mean i will show you the video 1 more time. This woofer was make to move in and out and when i crank it, its really really loud. Head to head vs JBL extreme 2, its no contest, bass and loudness i win, sound quality obviously not, well, probably not but it plays just fine really. Was i really just lucky putting this all together ? I mean i dont know but this thing shakes the room with its bass, and keep in mind that my phone microphone is very very bad at recording the bass, u would have to hear it in person to hear the bass:

 

audioguru

Well-Known Member
Most Helpful Member
It sounds good and it does what you want. The enclosure is large enough for the speakers. I notice that the woofer and passive radiator move together and the full range speaker moves by itself sometimes.
 
I didnt separate the full range speaker away from woofer so that is bad, i plan to fix it in the next speaker. Woofer is on 1 channel and full range on the other, didnt do any crossover or anything else. I plan to fix many things in the next versions of speakers i make.

The problem with getting speakers out of 2.1 system is that each speaker will be different. If i could find a certain type of speaker online, even without data, i could then just experiment with different enclosure sizes and passive radiators. And when i found the right type of passive radiators and size of enclosure, i could just reproduce this speaker and get the same result every time, if you know what i mean.
 
I got some new speakers today and did a quick test on them. I am not very impressed but i will be able to use them.

First speaker as it turns out is Peerless by Tymphany PLS Series 75F25AL04 3". Aliexpress stated 60-20.000 and 90dB sensitivity, parts-express for this speaker stats 100-20.000 and 85dB. I paid around 35€ for those speakers. I cant say much about bass until i put them in an enclosure, so far nothing spectacular, as is expected from cheap aliexpress speakers. But will be able to use them, so all good.


Second speaker is bulkier and also cost more, 59€ for a pair. Ali didnt include any data, i bought them only because a youtuber made a nice bass speaker with them. They arent very loud, prolly around the same as upper speaker. It does however make my table shake. Its amazing, as soon as i put them onto a table, it sounds like someone is banging the table. I am interested to see how they sound in an enclosure and if i can combine them with a tweeter on 1 channel and them on second channel. It was quite expensive though and for future it will be cheaper for me to just take the speaker out of an old 2.1 woofer system and use it since its around 4" and for sure gives good bass. I would be happy to find the actual model of this speaker, things written on back hint to peerless, but in youtube it states that its a samsung speaker

 
Btw just for testing with that 2x25W amplifier ... i tried running it at 24V and then at 12V. To be honest, i couldnt detect the difference, actualy 1 of the speakers didnt cut at high volume anymore. So for future speakers i might aswell do 3S instead of 6S ... parts will be cheaper, simpler, etc. 12V vs 24V sounds a lot but, isnt that only twice the power thats 3dB more? Or do i remember it wrong ?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Btw just for testing with that 2x25W amplifier ... i tried running it at 24V and then at 12V. To be honest, i couldnt detect the difference, actualy 1 of the speakers didnt cut at high volume anymore. So for future speakers i might aswell do 3S instead of 6S ... parts will be cheaper, simpler, etc. 12V vs 24V sounds a lot but, isnt that only twice the power thats 3dB more? Or do i remember it wrong ?
You remember it wrong - it's four times the power, and VERY noticeable.
 
Well then something else is wrong. Either my hearing OR this bluetooth amp actualy is a lot less strong as it says. And basicly comes near its limit at 12V ...
Whats also interesting, running this amplifier at 24V and going past 80% volume, speakers will stop playing for milisecond, play again, then stop. I thought its the speakers but no, i plugged them into my 2x100W amp and they went a lot louder without stopping noice. So i am guessing its the cheap amp fault. And since i was driving the amp with 24V 4A stable DC supply, im guessing a capacitor between power suply and amp wont really solve the issue ?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Well then something else is wrong. Either my hearing OR this bluetooth amp actualy is a lot less strong as it says. And basicly comes near its limit at 12V ...
Whats also interesting, running this amplifier at 24V and going past 80% volume, speakers will stop playing for milisecond, play again, then stop. I thought its the speakers but no, i plugged them into my 2x100W amp and they went a lot louder without stopping noice. So i am guessing its the cheap amp fault. And since i was driving the amp with 24V 4A stable DC supply, im guessing a capacitor between power suply and amp wont really solve the issue ?
There could be many reasons, but certainly the specs on those Chinese amps are pretty imaginary anyway.
 
Here is a review of some TPA3116 chinese cheap amp and i dont understand much of what the review is saying but i think its good:



So i am wondering will i get similar result from this amp:


Its the same chip but with added bluetooth and much needed volume button. What do you think ?
 

audioguru

Well-Known Member
Most Helpful Member
The TPA3116D2 amplifier IC is made by Texas Instruments. Their datasheet says its output into 4 ohms is 60W per channel at low distortion with a 24V supply. With a 12V supply the output into 4 ohms is 15W per channel at low distortion.

Your amplifier IC is hidden by its heatsink so maybe it is a cheap Chinese copy. We do not know if the wiring on the pcb is strong enough for the high currents.
The video shows 51W into 4 ohms at low distortion with a 24V supply which is a little less less than the 60W the datasheet shows.

HEY! The datasheet shows a stereo (2 channels) amplifier but the video shows a mono (1 channel) amplifier so something is VERY fishy. Maybe the Chinese amplifier has weak wiring so they paralleled the 2 channels. Doesn't your amplifier have 2 channels?

Your amplifier or power supply shuts down for a moment sometimes when overloaded. i think your power supply voltage drops when the amplifier plays loudly.
A capacitor between the power supply and amp blocks DC so the amplifier will be dead.
 

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