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-   -   Bluetooth speakers made by Creative (http://www.diyaudio.com/forums/full-range/203283-bluetooth-speakers-made-creative.html)

r6578 28th December 2011 03:26 AM

Bluetooth speakers made by Creative
 
Hello, everyone!

I am not sure if “full range” is a right place to post my question. Mods, please, feel free to move it somewhere more appropriate.

Anyhow, I’d like to start a thread on Bluetooth speakers.

Sorry if this is a sacrilege to discuss these not-even-near-HiFi plastic boxes in this respected Hi-End Audio forum. However, they do exist and they are very handy sometimes, and they surely can be modified to get some half-decent sound out of them.

I’m tinkering with Creative Bluetooth Speakers, models D80 and D100. They are, probably, the cheapest BT speakers available (AU $45 and $70), but for their price they are surprisingly well made. I believe that they have some potential for improving. Besides, if you stuff them up while modding, it’s not a big deal at this price.

If someone is interested (and The Moderators will not remove my post as Blasphemy), I can post some pictures of the internals and some basics on parts/schematics.

Please ask me some questions to get this post rolling.

planet10 28th December 2011 03:32 AM

The limit to the fidelity you can get with blue-tooth speakers is likely the information that Bluetooth is capable of conveying.

The cheap speakers are likely a good place to poach a working bluetooth receiver to build into your own (powered) speaker to ensure that the limitation is bluetooth.

dave

Pano 28th December 2011 03:46 AM

Yeah Dave, I like that idea. With known speakers you can get an idea of what the Bluetooth audio sounds like. Then go ahead with modifying the Creative speakers if you like the results.

Alex from Oz 28th December 2011 03:58 AM

I'm interested. Please post some pics.

Cheers,

Alex

r6578 28th December 2011 05:19 AM

Thanks for your response, guys.

@ Planet10 and Pano (respected Mods):

Thank you for your suggestion. There is even easier way of doing it. I was contemplating to buy BT audio module on e-Bay and put it in some old ghetto blaster. BT modules come from China and cost around $15 for external one (in small enclosure) or just a PCB-kit. It went nowhere, because:
a) Shipping time from China is several weeks
b)I don’t have a ghetto blaster.
Then I saw Creative D80 ad on the net and decided that for $45 I can’t go wrong. It doesn’t have unnecessary things like cassette player, radio etc., it’s lighter, smaller and looks better. I can’t make decent quality box with front panel/speakers/amp/power supply for $45, sorry.

Speaking of fidelity of Bluetooth link – it is not too bad, really. I wouldn’t suggest using it in HiFi setup, but for portable audio it is quite acceptable (for my ears, anyway).

@Alex from Oz:

I have some pics of D100 on my workshop computer; I will post it later today or tomorrow.

r6578 28th December 2011 12:01 PM

6 Attachment(s)
As promised, some pictures of the internals of Creative D100 speaker.

Its ported enclosure with 3-inch wide-range speakers driven by TI class D amplifier TPA2012D2. Amazing fact (for me, anyway) is that there is no heatsink for 2x2W amplifier.
All electronics runs off 4XAA cells or external 5V power pack. Bluetooth receiver module is based on 57F68 chip made by CSR perhaps, some BlueCore family.

The enclosure is sealed pretty well with some kind of foam everywhere, but there is neither sound absorbent padding (or whatever you, pros, call it) nor vibration damping coating. The sound is pretty ugly, therefore. The upper flat surface of the case vibrates a lot. If I press on it with my hand, the sound becomes a bit better. The bottom surface does not noticeably vibrate, because of rigid battery housing.

Any suggestions on improving the acoustical properties of this plastic box? Or maybe I am barking at the wrong tree? I have almost zero experience with audio design.

Alex from Oz 28th December 2011 07:38 PM

There are some things you can do to improve the box.
IME you will improve the sound, but it will leave you hungry for more.
So treat this as a learning adventure.

If I was going to keep the box as is, here's what I would do:
1. Buy 6-8 packets of Blu Tac and line the inside of the box with it.
Then listen to the sound.
2. Cut some 4 mm x 2 mm rectangles of duct tape and stick them
on the back of the box around the port opening in the EnABL pattern.
Listen again.
3. Add a very small amount of stuffing being careful not to obscure
the port. Listen again and add or remove stuffing until it sounds right.

There is plenty more, but start with these.

Cheers,

Alex

r6578 29th December 2011 01:33 AM

Alex, your reply has simply swept me off my feet. Blue Tack as a vibration dampener!!! That is bloody ingenious! To think of it – it’s perfect! Non-hardening, very viscous, easy to apply, cheap – the list just goes on! Up yours, Jaycar, with your bitumen-based lining. (for non-Australian readers – Jaycar is electronics DIY shop)

Only one thing about the lining – doesn’t it rob me of the internal cabinet volume? I heard that volume is important in vented boxes and the port is tuned in accordance with it.
Or maybe I will compensate for this loss when adding some stuffing? BTW, is synthetic stuffing for toys any good? I’ve got plenty of this, as my dog rips my kid’s toys on a regular basis. Can I wrap it in some acoustically transparent fabric to prevent it from getting into the speakers and port?


About EnABL pattern – does it go on the inside or on the outside of the box? I know nothing about it, there is a bit of googling/homework for me to do here.
Funny thing about the back panel of this box is that I do not feel any vibration there at all. Could it be because of that factory protective anti-scratch film is still there? (I did not bother to peel it off). The plastic thickness is the same everywhere, I guess. I have a strange feeling that the fact of the port being linked to the top panel (see pictures) has something to do with severe vibration of the top. Then again, I know nothing about speakers.

Thanks again, Alex. I’ll get stuck into it and keep you posted.

Alex from Oz 29th December 2011 04:40 AM

1 Attachment(s)
Yes, the Blu Tac lining will reduce the volume but adding stuffing will help to
compensate for this somewhat. Toy stuffing should be fine in this case.
Just make sure that you tease it out so that it is not to densely packed.

EnABL for ports is best on the inside of the port. However the long slot ports
like the one on this unit are too fiddly given the unit we are working with.
Best bet is to stick the pattern around the port opening on the back of the box.
I guesstimated the port size from your picture and have drawn up a very
rough pattern to give you an idea of how to do it. The blocks closest to the
port should be about 1mm from the edge. Refer the attached pic.

BTW, Norton All Weather Tape (Bunnings has this) would be even better than
duct tape but it costs nearly three times as much.

Cheers,

Alex

Pano 29th December 2011 03:52 PM

All good advice, but I would scrap the plastic box. Build something out of MDF or plywood.
It maybe never be great, but you will have built something and learned something. That's how you get started in DIY. You can learn just as much from what doesn't work as from what does.

And you might just build something you really like. ;)


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