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DIY bluetooth speaker

Where do i find the Qtc value of the speaker:

 

audioguru

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The article says to use 0.707 as Qtc for a smooth low frequency roll-off.
 

audioguru

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It is a cheap little, low power, high resonant frequency speaker with a Qts much higher than a hifi speaker. Its frequency response shows it as a peak near resonance. I think it produces "boomy" one-note bass.
 

audioguru

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The error will not compute a sealed enclosure and the program makes a huge mistake for a ported enclosure.
Years ago I used Boxplot program that does not work in a modern Windows version.
Now I tried another program but the little speaker needs a ported enclosure.
 
This calculating takes the whole fun out of building a diy cheap speaker. The one i last built had awesome bass and i am sticking to this totaly, it has great bass. For ppl drinking beer outside. Now what i dont understand is this:

I used a 4" speaker from ultra cheap logitech 2.1 system. In specs it says 9W (dont know if thats the amp or speaker max). Its a 4 ohm speak so that shouldnt matter much, it just adds 3dB more then 8 ohm thing. My point is, that speaker is LOUD and has good bass. And since its from such a cheap logitech set, prolly 1 ofthe cheapest u can find, surely it doesnt use a good woofer speaker thats expensive. And then i go buy dayton 115 something which has worse bass in my opinion and also, its so silent its useless.

I want to find the speaker that was in logitech woofer, it is completely perfect. The problem is there is no name written on it and browsing on google gives no information. So its basicly impossible to find.
 

audioguru

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I found this software that works to design enclosures: https://www.ajdesigner.com/speaker/

The little Visaton speaker in a sealed 3.3l enclosure produces +2.5dB at 200Hz, is -3dB at 121Hz then drops off at 12dB/octave. It does not calculate in a vented enclosure.

The Dayton TCP-115 4" woofer in a sealed 1.5l enclosure produces a flat response then is -3dB at 97Hz then drops off at 12dB/octave.
In a vented 3.1l enclosure its response is flat then is -3dB at 53Hz and drops off at 24dB/octave.

I could find no detailed spec's for the AliExpress 3" speaker. 60-20kHz means nothing since it might be good at +/-3dB or it might be horrible at +/-30dB.
Is it 40 Whats or is it 40 Watts momentary peak?
 

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Thats the thing about the speaker from aliexpress. All the data is written there, no specifics. Finding that company, GHXAMP is also impossible. Like i said i only saw it playing nice in a video and said, what the hell, lets test it, if it doesnt work as i want, i can always sell it to someone else who maybe will use bigger enclosure. I will be sure to report my findings.

Damn, the dayton ... 1.5l sealed enclosure is totaly doable, i mean, i could even go for 3l ported or 3l with passive radiators. The only problem is it is to quiet, really really to quiet. Maybe good enough to sell to some ppl that care more about bass then loudness. But to me its the oposite. And it will be hard to combine both.

Btw today i showed my speaker to my uncle and was once again amazed at the bass, god damnit, excuse my language, it really really packs a punch. I just wish i had a way to test the effect of passive radiators. Like somehow seal both ends, listen, then unseal them and listen again. For my next speaker, i will test it once sealed, then drill holes and add passive radiators and test again. Maybe if i press both ends of passive radiators with some thich foam, to make sure they cant move in and out, will that do the trick ?

Also, i would give my liver to figure out what speaker is that cheap logitech from the woofer. It is completely what im looking for: good bass + loud. It prolly only plays till like i dont know, 1000Hz or maybe 3000Hz, but goes really low. And thats great for me, i just add a tweeter and im good to go. But there is completely no way for me to find what speaker is in that woofer.
 
Ok can you explain 1 thing to me since u know much more about sound then me ? OK but please read well cause i just cant understand this.

I dissasembled a cheap logitech 2.1 system and took its woofer out, its a 4 incher. It goes down to 40Hz, and plays 80Hz very loud. In other words its bass is perfect and its sensivity is great. Ok now get this. This system cost 50 dollars when it was new. This means that the speaker probably cost 5 dollars in order for company to make any profit.

Ok. Now i go search for speakers up to 50 dollars online. Mind you, looking for a SINGLE speaker for the same price as 2.1 system for logitech. And i can find nothing, nothing that will go down to 80Hz and have decent sensivity. This makes completely no sense to me. I even went and found a person with that logitech system that will send me a second hand one for 20 dollars. So i will buy all the systems and make speakers out of them.

But to sum it up, this makes no sense. I should be able to find a speaker that will at least compare to this logitech thing. But i cant. I literaly went through all 4" woofers on soundimports and it all either has no bass or has sensivity that only the owls and wolfs will hear. And yes i could just go and get a 500W amplifier and make it louder but i want my batteries to hold. And if it works with logitech woofer, why the hell cant i find a replacement ? Ofcourse logitech speaker has no things writen on it so its impossible to track it down.
 

audioguru

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Logitech spec's then orders (maybe they make the speakers?) thousands or millions of good speakers so they are cheap. How many do you design then buy directly from a factory or make by yourself?
 
Well alright, then find me a good 4" speaker like the one from logitech system NO MATTER the cost. It can dost 1.000 dollars. Just find it and let me see the link.
 

rjenkinsgb

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Have a look at these:-



 

audioguru

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The three little mid-woofers will not produce good bass in a small portable enclosure.
The 4.5" Dayton needs a large sealed enclosure but it has high sensitivity.
The 4" Peerless has a resonant frequency too high and poor sensitivity.
Both above need a crossover network and a tweeter.
The Vibe has no detailed spec's.
 

audioguru

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Wealthy people buy expensive assembled little speakers like the JBL or the Bose one. Nobody buys what is inside them.
 

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