EEVblog Electronics Community Forum
Products => Crowd Funded Projects => Topic started by: 8163jb on April 28, 2015, 10:08:24 pm
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Here's the project! (https://www.kickstarter.com/projects/doayee/bluetooth-audio-link)
"The BAL, a development board for Bluetooth Audio devices. With BAL you can do a number of things, ranging from simply connecting your phone or laptop and streaming high quality, pop free, stereo audio from it, to more complex features like connecting a micro-controller, and controlling the connected device via Bluetooth. With an on-board pre-amplifier and pop filter, you can plug in headphones and listen right away, at CD quality."
Let me know any questions you have :) thanks!
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I am not sure I see the utility of this. If it were battery powered and had an output buffer/amp for headphones then it would be much more useful IMHO.
Edit:
OK, I see the amp is there, sorry. What are the specs on that amplifier?
Second edit: Sorry for being so lazy, looked it up. It does not look like a good amp for driving headphones. And like I said no battery?
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It can be powered from 4 AA battery's, if you had the right holder (I don't think they're expensive) and yes although the onboard amp is not ideal for headphones it works just fine! Though it is more suited to go into a main amp and a speaker system.
And with regards to the module interface, I found it clumsy when I started, but actually now I'm used to it it's okay :) I think it's outweighed by the stuff the chip can do!
P.s. sorry for the late reply, being a student in exam time isn't fun :(
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>44.1KHz Output DAC (CD quality)
dude, cmon :-DD
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If I could put a higher quality DAC in the RN52 I would've done :P but unfortunately that's that! You don't really need much better for this kind of application anyway, you wouldn't be able to hear the difference with a better DAC.
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CD sampling speed would be more accurate, but not quality, A2DP means awful lossy compression
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Yeah but saying CD quality means alot more to people who don't understand sampling speeds straight off the bat, it's a much more useful comparison. And those who do understand sampling speeds don't need the comparison, as they have the sample rate! It's just helpful to explain it to people over a broad range of knowledge, even though yes, sample speed is more technically correct :) And although A2DP is not lossless, it mainly has it's "awful quality" reputation from audiophiles, in reality you can't hear it. I've never had anything less than crisp, clean audio out of the RN52!
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£40 is a bit high for a naked BT module and a less than arduino board. ymmv.
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Especially when eBay has an alternative with the same amp, BT4.0 and almost the same functionality for only 13 dollar shipped.
But trying never hurts, and you reached your goal :)
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Yeah if you just wanted to stream audio, there are definitely better alternatives :) but this is definitely a more flexible board. The real advantage with BAL in my opinion is being able to talk to the chip via Serial, and the AVRCP functionality, which combined with SPP gives you the potential for building it up into a complete media station, with volume and track control, and all the track data etc streamed into the RN52 and out to a local micro. Stuff like that!
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The RN52 supports aptX
thats better, weird authors didnt mention it on KS, I would imagine sound quality to be one of the most important features of a bluetooth sound playing gadget
>support for codecs such as SBC, aptX®, and AAC
AAC? hmm, interesting. aptX is a proprietary piece of shit(like dolby encodings) costing $$$ to license and enabled only on higher end phones (unless you hack firmware and copy libraries over), AAC is standard and would cut on reencoding. Still, at this point one needs special piece of software on the other end, so why bother with BT when you can just stream lossless music over wifi
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I have seen too many similar product in market, which costs only 1/10 the price of yours.
and they are beautifully packaged
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apt-x and the low-latency version (new) is the best we have right now over BT. its not 'perfect audio' but again, its the best we have right now.
one question came up from a friend; maybe this will help solve his problem. he wants to have a few channels of wireless audio but the key is to keep them in synch. the app is to have a digital crossover split the spdif full spectrum source into 2 spdif outputs, one HP and one LP. that's doable today without too much trouble but then he wants to send the HP and LP still in digital form, over the air to remote spkrs that will finally convert to analog, drive local (chipamps?) and then spkrs.
he first tried composite ('yellow') video over an rf link and that works but not great. and only for one spdif stream.
it might be a nice thing, but if you had some way to synch clocks or streams and have the ability to send several parallel audio channels over rf, that might have some HTPC apps as well as pro audio apps (lower end pro).
I did suggest he look at 2 BT transceivers but again, how do you synch them? does not sound easy. maybe one pair had some packet drop and has to retry but the other pair didn't; so its a buffering thing as well as a clock synch thing.
any ideas?
oh, and I have seen some BT modules that have toslink on them. not sure if they are truly digital or just going thru a cheapie a/d or dac (?)