2.1 build, bluetooth

maxximus

Member
2014-02-22 2:11 am
I am looking to build a Bluetooth cube with one 5.25" sub and two small speakers.

I had originally started a thread here http://www.diyaudio.com/forums/subwoofers/290726-8-sub-choice-small-bluetooth-system.html

Based on that I have bunny trailed a bit and am building a small system of 2 4" cubes that are coupled together, but can be split for better sound using the 3" TB's.

However back to my original idea. A decent sub in the smallest box possible and two good drivers with it. I'm looking at the Tang Band sub http://www.parts-express.com/tang-band-w5-1138smf-5-1-4-paper-cone-subwoofer-speaker--264-917 because it takes a very small box and has decent output. .1cuft box sealed

I am thinking of using 2" speakers
http://www.parts-express.com/fountek-fr58ex-2-neodymium-full-range-speaker-driver--296-725

I like these because they .01 cuft sealed box or smaller and works well from 800hz up.

Right now I am thinking of about a 7" sealed cube.

It would be cool to have access to a speaker store to just test and build... I find stuff works out different in real life than designed in my head.
 
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I am thinking of using 2" speakers
Fountek FR58EX 2" Neodymium Full Range Speaker Driver

I like these because they .01 cuft sealed box or smaller and works well from 800hz up.

Well 800 hz seems too much, 80 Hz being better as uniformly adopted around the globe. Even 60-70 Hz but no more than 100 Hz .
Those little 2 inches are 15 W; I don't know your usual playing volume and they might be ok from normal to loud in a room - At loud volume the magnet starts to warm a lot- considering a metal box to help to dispose of it

Of course they need to be filtered from frequencies below 100 Hz ( it's written 130-20000 hz linear operation ; you might consider a 3 " for an extra octave ) as well as the subwoofer.
 

maxximus

Member
2014-02-22 2:11 am

maxximus

Member
2014-02-22 2:11 am
Can the 3" TB's handle being crossed at 100hz? and would these two make a good pair?
I read somewhere it is good to cross slightly inside the rating of the speaker. The 3"TB's are rated from 100-20,000 HZ.

I don't want to invest all that money if they don't match well. If they do I think they would sound amazing.
 

maxximus

Member
2014-02-22 2:11 am
After looking at the final box dimensions and driver frequency plots I don't think I want to go with the W3 and W6.

I am now looking at using 5.25" TB W5 (ported) and the 2" TB W2 and crossing them higher in the 5-800 HZ range This would give me a cabinet size of around 9x14x7.5 that is very close to the size I am looking for.

Should the 2" TB's be ported for this style or would they be ok sealed?
 
Naaaaahh! It doesn't work like that ! You've gotta do some research what a subwoofer is supposed to do; I mean, you can go ahead your own way and have your 5 1/4 " working till [ insert good linear passband response till it drops natuarally] but usually it's no good having the two channels mixed mono
when they are supposed to work in stereo.
It's related mostly on how different frequencies change dispersion ( or beaming ) and also, for the woofer, changes from omnipolar to directive in semi-space ( the baffle etc. )
:eek:
 
Hi maxximus,

friend and I are planning to do something similar to what you decided to do; and choose exactly the same drivers (1xW5-1138 & 2xFR58ex - planning to xover them at cca. 250Hz). I decided to use some 2.1 tpa3116 based amplifier and 24v switcher PS. Bluetooth car media players also look suitable. I hope to pack everything in 25cm cube.
 
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Cool and doable - within reason

I have also thought about a similar build or two.

I planned to use a reasonable woofer 5-6", like Mission CP168 paper cone woofer (laying about here) and visa ton frs5x 2" cone midtweeter and it looks ok in simulation corrssing the HP filter at 5-700Hz 4th order. It is SPL limited though, and I plan to try three of the frs5x instead to give better headroom.

The other build is a W3 with lower xmax than many. Safest bet for me here is HP at 400 Hz and again 4th order. But I lack the right woofer, 8" or larger.

Or....there's the Alpair 5 and some 10" bass guitar speakers I have left over from a dead cab....
 
Caveat being...

I also think filtering a 2.1 from mono bass to stereo muds and HF is ok... but I fear that filtering at 400 Hz you'd risk losing some of the localisation cues in stereo recordings, but 250Hz is really pushing it.

With something like W2-800SL, you get 87dB to start with....down to maybe 500Hz. But good for conventional stereo, maybe not so good for 2.1...
 

maxximus

Member
2014-02-22 2:11 am
The way I am designing mine may well end up being close to a cube. The speakers will be on either side of the sub as close as I can fit them. The idea is to keep it as small and as portable as possible within reason. I know it is not perfect but it will still blow any off the shelf Bluetooth out of the water.
 
Everything works as planned :) After some burn-in time, I'll measure driver responses and perhaps add passive filters if needed. But, I'm already very satisfied with first impressions.
 

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