Testing ebay bluetooth audio modules

Jan Panteltje · 2015-02-14T15:11:45+00:00

Was testing several 'in ear' - and 'next to ear' - or whatever earplugs, I decided those were mostly shit (sounded like that), and I wanted my Sennheiser HD201 headphones to work with bluetooth. I got some of these from ebay, to experiment with: Some googling for chip datasheet, and found datasheet of this module, ran a test setup _without_ caring about wire length, decoupling etc etc... Sound is great! Module close up: The transmitter is this one: So at about 5 $ (free shipping of course0 you can make your high end headphones bluetooth capable. One remark: The audio out if not relative to ground, but relatibe to an audio common pin, where I put the big 100uF cap. Just needed to try that good old soldering iron again .... This is of course a real audiophile posting. those HD201 headphones are cheap and sound good, this is my second or third...

Feb 14, 2015 20 Replies

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On a sunny day (Tue, 16 Feb 2016 16:15:10 -0800 (PST)) it happened snipped-for-privacy@gmail.com wrote in :

wget

formatting link

Don't remember how I made it...

I use 'siggen' in Linux to generate tones, also wrote some stuff on the spot when I needed it.

# siggen -h siggen Ver. 2.3.10 (May 2008) Ncurses based Digital Signal Generator Usage: siggen [flags] [waveform [freq [param]]] Defaults: SINE wave, output to /dev/dsp, 22050 samples/sec, 16 bit stereo samples if possible, else 8 bit and/or mono. Valid waveforms are: sine cosine square triangle sawtooth pulse noise off Default Config files are ".siggen.conf", "$HOME/.siggen.conf" and "/etc/siggen.conf", searched in that order. flags: -s samples generate with samplerate of samples/sec -8/-16 or -b 8|16 force 8 bit or 16 bit mode. -1,-2 force mono or stereo (1 or 2 channels) -NB n Number of Buffers to create is n, def. is 3 -BPS n Number of Buffers to play per sec, def. is 15 -res n n=1, 0.1 or 0.01 - frequency resolution

I have several bluetooth modules, headsets... Never measured one for frequency range. Those are mostly toys (the headsets) in my view, not HiFi,

Main point for me: If it does not sound good, then I do not use it.

For TV audio bluetooth would be OK, mostly noise and bad background music anyways. Apart from a good mike you also would need a deadroom (no sound reflections) for measurement, as moving it a few cm would change everything. IIRC they use special boxes to test mikes?