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Topping BC3 Review (Bluetooth Receiver) & BT CODECs
- Thread starter amirm
- Start date
The one mentioned above I did manually, but the one behind the spoiler below used the level step feature. The graphic however was produced with gnuplot because REW did not show THD+N vs signal. Attached are the REW mdat file, the export file from REW which contains the data, and the script which created the graphic from the export file. I'm sure one could also use Excel or any other spread sheet program to create nice graphics.
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definitely the later.
The latter choice will be fully lossless, assuming your source material is 44.1khz/16bit and the Belkin device doesn't do any wacky resampling or screw things up in other ways. To clarify a bit on how AirPlay works for audio streams:
Mods, feel free to delete this post if it's too off-topic. I feel it's relevant because people are evaluating high-quality wireless solutions such as LDAC via BT and are weighing it against the alternatives. But, no hard feelings if you disagree.
I'd choose whatever didn't require additional pairing and could do multi-room. If something used RF, Bluetooth, WiFi, etc. it wouldn't matter if it performed.
Since this doesn't do either of those things and the Chromecast Audio does, I don't have a use for it.
jannek
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CheapskateCCAOwner
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In addition, with Chromecast Audio (CCA), your phone (or whatever you're using as a controller) is not the source of the audio or audio stream, so the CCA's audio signal is not impacted by the strength of your controller device's WiFI signal or its proximity to your CCA device. These factors (in addition to multizone and others) means that this device can't compete as a direct replacement for Chromecast Audio.
But.....none of the above matters much to me, as I don't mind keeping my phone close to my streaming device and I rarely make use of multizone (though I do have 2 CCAs). So with that, I feel that this cheap Topping device can in fact act as an acceptable substitute for Chromecast Audio. I currently have my CCA feeding my Topping D50 DAC (via Toslink); replacing my CCA with this device would be a drop-in-switch, and since I'm using a Google Pixel 2 XL, which supports LDAC, there would be little-to-no degradation in measurements (and sound).
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My strange subjective experience with AirPlay1 is that my Denon AVR sounds weird with it (probably Denon or my configuration fault), and I hate the delay between a selection and actual playback.
Bluetooth is for sure lossy, but it is universal - anyone, anytime with a phone, PC, Mac or tablet can instantly start streaming audio. AirPlay should be higher quality, but if Bluetooth is good enough, then Bluetooth is so much more universal that it might just be "better"
For proper sound quality I would still have to stick to USB and SPDIF.
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Wow! I didn't expect the LDAC disparity to be that drastic at all. Makes me really glad I chose Sony 1000XM3's before everything supported LDAC.
Now I just need to figure out how to get LDAC to work on my smart brick. A root was found for it last year, but it only works with Android 7, which didn't have the codec built-in yet.
Now I just need to figure out how to get LDAC to work on my smart brick. A root was found for it last year, but it only works with Android 7, which didn't have the codec built-in yet.
OP
- Thread Starter
- #111
I explained that it the other thread and there is nothing funny about it. A pure tone at 1 kHz is a very simple signal that all lossy codecs need to handle with ease. It is not outside of the scope of the encoding of any of them. After all, I can decompose any music into corresponding tones and 1 kHz would very well be one of those tones.
The MQA test the blogger ran used highly complex signal such as white noise, impulse and importantly, spectrum that went to full 44 kHz (88 kHz sampling). MQA codec is an unusual codec in that it is designed to take advantage of the statistical distribution of music. Feeding it "rectangular" PCM content is outside of its design constraints and so it just doesn't work with it.
Also, I am testing hardware here, not just a codec. And our hardware tests have always had simple tones so we could compute SINAD and such. We have seen how that is impacted not just by choice of codec, but noise and distortion in the hardware.
Bottom line: I know what I am doing with the test signals, the other party doesn't.
My test signals are perfectly legal and defensible for these codecs. His is not for MQA codec.
OP
- Thread Starter
- #112
Video review, frequency response and another distortion test added to the review.
Maybe I'm a bit slow, but the panther seems to have just dropped a fried egg on his foot.
My reading of such an image is "whoops, fail".
Maybe that isn't quite the right image for this product. But cute panther.
My reading of such an image is "whoops, fail".
Maybe that isn't quite the right image for this product. But cute panther.
There's a fair number of such transmitters that accept optical or analog connections. I'd be dubious of most ADC's on a combo <$100 device *if* highest possible SINAD is your chief concern. Audibility is another story, as always.
@amirm thanks for testing this, I'm always curious about these little adapters because they can offer such easy fixes compared to wires. As an Android user, a few key points:
There's some kind of bug/feature that prevents you from locking LDAC sample rate. It always defaults to Best Effort once the connection is lost, and you have to reset it manually via developer options once connection is re-established. Even as an advanced user, this is tiresome yet I'm not aware of any fix. Maybe rooting? I'm not really in that space because, working from home, I need maximum reliability on my phone.
Many android devices, including my S10 5G, have dropouts/stuttering with the LDAC rate set to 990. It must be a fairly prevalent issue because the Qudelix app offers suggestions on how to work around it during configuration. In my case, I have to completely disable Location services but many people simply have to keep their screen off. Another deal breaker for a typical user.
Finally, latency on 990 LDAC can be as high as 250ms if not higher (device dependent). Obviously a non-issue for simple playback but videos can degrade into kung-fu mouth.
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interesting to see how much the codec impacts your measurements, so does it mean that :
1/ if i only listen to 128k mp3 i should not care about which bluetooth codec i use ?
2/ should i not buy an external dac because my phone integrated dac is good enough for 128k mp3 ?
thanks.
1/ if i only listen to 128k mp3 i should not care about which bluetooth codec i use ?
2/ should i not buy an external dac because my phone integrated dac is good enough for 128k mp3 ?
thanks.
Lunafag
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Well, that seems like huge a waste, I was looking for a purely digital solution. All I found is that on Linux using pulseaudio you can transmit LDAC with any bluetooth dongle. Also fiio m5 seems to be able to do this in DAC mode.
FWIW, I once tested a cheap BT receiver with RMAA and the best case SBC codec frequency response wasn't as bad as what Amir got:
Even the small roll off you see is not likely to be caused by the SBC codec, because with a lossless (USB) source the roll off was still there (but smoother, not jagged).
Mind you, this was the best case scenario, with a good signal and probably the maximum possible bandwidth (the bandwidth changes depending on the signal strength). The worse measurements were anything from similar to what Amir got to even much worse, with distortion in the middle frequencies.
The bottom line for me is that Bluetooth is almost useless for hi-fi/audiophile listening. You can only get good audio quality in the best case, with an optimal signal. And if you need to be that careful about maintaining a good wireless signal, you might as well just use a wire.
It's still okay for some casual/non-critical listening, though. The convenience sometimes is just too valuable.
Even the small roll off you see is not likely to be caused by the SBC codec, because with a lossless (USB) source the roll off was still there (but smoother, not jagged).
Mind you, this was the best case scenario, with a good signal and probably the maximum possible bandwidth (the bandwidth changes depending on the signal strength). The worse measurements were anything from similar to what Amir got to even much worse, with distortion in the middle frequencies.
The bottom line for me is that Bluetooth is almost useless for hi-fi/audiophile listening. You can only get good audio quality in the best case, with an optimal signal. And if you need to be that careful about maintaining a good wireless signal, you might as well just use a wire.
It's still okay for some casual/non-critical listening, though. The convenience sometimes is just too valuable.
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I don't understand the 20 20k measurements. LDAC cuts off all output beyond 12-14k so you should not have flat out there at 20k
Aptx is selective in it's frequency cut off, saying essentially it is removing sound that is inaudible since there is sound to the left and right that masks what it removes. So the measurments make sense, that what it is designed to do, distort the flat curve. That is the loss in the lossy signal.
How does LDAC compress if it has perfect fr?
Aptx is selective in it's frequency cut off, saying essentially it is removing sound that is inaudible since there is sound to the left and right that masks what it removes. So the measurments make sense, that what it is designed to do, distort the flat curve. That is the loss in the lossy signal.
How does LDAC compress if it has perfect fr?
By modulating the noise floor.
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