Has anybody bought a CSR programmer from Aliexpress or another source? I've found several but haven't actually purchased one yet. I'd really like to try this.
I don't know them, but I have used an UM232H to program the CSR chip without any problems (was still in the drawer).
I did some research on BT (aptx/AAC/SBC) a few years ago to evaluate range and audio quality, as well as the power of the internal kalimba DSP.
This board was just build to compare it to 44.1-192kHz/24bit with the ability of fast A/B switching.
In the end i came to this conclusion - SBC is unusable!
Aptx is not supported by IOS or most of the Android devices and to get a valid AAC license is near to impossible.
Furthermore AAC decoding is a heavy load to the chip (long delay), and just in case you get a aptx license for evaluation you should take a look on listing process at bluetooth.org.
One or two (?) years ago, they changed there process from "free of charge" to "very expensive" ...
The range (apt-x) with the best BT modul and best available (certified) external antenna (Kinsun 6612) was disappointing.
SBC up to 30m on open field, but with higher bandwidth maybe 5m for a stable connection (without having something in the way).
Even having the source in your pocket is a problem with high bandwidth algorithm.
But for a "cheap" boombox SBC will be okay.
Just as a hint, if you buy a CSR chip with valid AAC and/or aptx licence, every change in FW will make the key unusable.
This key is unique (MAC+software) and (i don't remember exactly) encoded(?).
I did some research on BT (aptx/AAC/SBC) a few years ago to evaluate range and audio quality, as well as the power of the internal kalimba DSP.
This board was just build to compare it to 44.1-192kHz/24bit with the ability of fast A/B switching.
In the end i came to this conclusion - SBC is unusable!
Aptx is not supported by IOS or most of the Android devices and to get a valid AAC license is near to impossible.
Furthermore AAC decoding is a heavy load to the chip (long delay), and just in case you get a aptx license for evaluation you should take a look on listing process at bluetooth.org.
One or two (?) years ago, they changed there process from "free of charge" to "very expensive" ...
The range (apt-x) with the best BT modul and best available (certified) external antenna (Kinsun 6612) was disappointing.
SBC up to 30m on open field, but with higher bandwidth maybe 5m for a stable connection (without having something in the way).
Even having the source in your pocket is a problem with high bandwidth algorithm.
But for a "cheap" boombox SBC will be okay.
Just as a hint, if you buy a CSR chip with valid AAC and/or aptx licence, every change in FW will make the key unusable.
This key is unique (MAC+software) and (i don't remember exactly) encoded(?).
An externally hosted image should be here but it was not working when we last tested it.
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Aptx is supported by by OSX, AAC by IOS.
I hadn't any trouble changing keys in the firmware. AAC/APTX everything worked fine after modifications.
(As long as you stay with the configuration tool and music manager)
Who needs 30m range? 🙂
SBC is "low grade" for sure, but will you hear it, when people stream their Spotify/Soundcloud stuff encoded in low nitrate MP3/AAC? The source quality is "low grade" as well. 🙂 And what about those MP3 via SBC?
I hadn't any trouble changing keys in the firmware. AAC/APTX everything worked fine after modifications.
(As long as you stay with the configuration tool and music manager)
Who needs 30m range? 🙂
SBC is "low grade" for sure, but will you hear it, when people stream their Spotify/Soundcloud stuff encoded in low nitrate MP3/AAC? The source quality is "low grade" as well. 🙂 And what about those MP3 via SBC?
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Thanks for all the information doctormord. Doesn't seem like its worth pursuing a DSP option if the bluetooth receiver will be so low grade.
I've been really interested with the idea of a single wireless speaker that is able to tune itself to the room. Similar to the Sonos "Trueplay" feature, but DIY. Looks like it might not be an easy option, haha.
I've been really interested with the idea of a single wireless speaker that is able to tune itself to the room. Similar to the Sonos "Trueplay" feature, but DIY. Looks like it might not be an easy option, haha.
Well, i'm doing a baseboard for the CSR8645 now, as there are always problems with bluetooth, as far as i'd read.
Nothing fancy, simple setup.
Topic here:
http://www.diyaudio.com/forums/digi...0-aac-apt-x-module-baseboard.html#post4595155
Nothing fancy, simple setup.
Topic here:
http://www.diyaudio.com/forums/digi...0-aac-apt-x-module-baseboard.html#post4595155
Configurable I/O pins?
Hi, I am working on a headphone with multiple I/o pins which control not only playback but a few other functions of the smartphone.
Can you tell me if these modules available on aliexpress, ebay etc can be programmed to have different functions from these input pins?
Also, the led needs to be more than just red and blue.
Thanks
Hi, I am working on a headphone with multiple I/o pins which control not only playback but a few other functions of the smartphone.
Can you tell me if these modules available on aliexpress, ebay etc can be programmed to have different functions from these input pins?
Also, the led needs to be more than just red and blue.
Thanks
Bluetooth board clipped AUX signal
Hi, I’m testing the following Bluetooth board
Atp-X Bluetooth 4.0 Multi-point Connect Board Audio Receiver Stereo Sound Module | eBay
and noticed something is wrong:
without any BT signal, I applied a sine waveform at the AUX input, and noticed that the negative peaks of the waveform at the board output was clipped at about 0.7V.
I don’t have the schematic, but it seems that the selection between BT signal (when present) and AUX signal (if BT is not present) is made by two analog switches (JC5R) powered between 0V and 3.7V, one switch for right channel, the other one for the left channel.
For each analog switch, both the inputs and the output are at 0V DC bias, so clipping of the input signal at -0.7V seems caused by the input protection diode (between input and ground).
Each input of the switch is connected to ground with a 43 K resistor and AC coupled to the input signal; I connected each input to the +3.7V supply with a 50K resistor, obtaining a bias of about 1.6V; now I can increase the AUX signal level until about 2V peak, without clipping.
It’s hard to believe that this could be a design mistake, but I can’t find an alternative explanation.
Did anybody experience something similar?
Hi, I’m testing the following Bluetooth board
Atp-X Bluetooth 4.0 Multi-point Connect Board Audio Receiver Stereo Sound Module | eBay
and noticed something is wrong:
without any BT signal, I applied a sine waveform at the AUX input, and noticed that the negative peaks of the waveform at the board output was clipped at about 0.7V.
I don’t have the schematic, but it seems that the selection between BT signal (when present) and AUX signal (if BT is not present) is made by two analog switches (JC5R) powered between 0V and 3.7V, one switch for right channel, the other one for the left channel.
For each analog switch, both the inputs and the output are at 0V DC bias, so clipping of the input signal at -0.7V seems caused by the input protection diode (between input and ground).
Each input of the switch is connected to ground with a 43 K resistor and AC coupled to the input signal; I connected each input to the +3.7V supply with a 50K resistor, obtaining a bias of about 1.6V; now I can increase the AUX signal level until about 2V peak, without clipping.
It’s hard to believe that this could be a design mistake, but I can’t find an alternative explanation.
Did anybody experience something similar?
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