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Topping BC3 Review (Bluetooth Receiver) & BT CODECs

The Jniac

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This is most impressive. Now, if only Topping would take their excellent engineering and design a portable DAC+amp that also had an outstanding Bluetooth implementation. They would not necessarily even need to come up with an entirely new design if they just stuck the guts of this into one of their existing portable devices.
 

infinitesymphony

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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).
Exactly, most people wouldn't consider a Bluetooth receiver to be a drop-in replacement for a device that can work as a wireless lossless DLNA transport with multi-room capability. The proof is in the fact that the now-discontinued $35 MSRP Chromecast Audio is selling for $100+ used. It was a Swiss Army knife that suited many purposes.

Given how inconsistent Bluetooth integration is among manufacturers I think trying to do better than something like a Logitech Bluetooth Adapter ($30) is a lost cause because the SNR and frequency response are going to suffer somewhere along the way anyway.
 

staticV3

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If only we could transmit in LDAC from PC. Couldn't find any dongle like that.
The Fiio BTA30 should allow you to transmit from a PC via LDAC to a Bluetooth receiver, but it's not cheap.
 

staticV3

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It only transmits in LDAC from analog inputs, not from USB. I already found a solution on ASR - Shanling M0 is confirmed to transmit in LDAC in USB DAC mode.
https://www.audiosciencereview.com/forum/index.php?threads/what-about-bluetooth-emitters.17152/
Ah yes, my mistake
Screenshot_20210528-232147.jpg
 
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amirm

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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 ?
Not at all. You should use the best codec on Bluetooth so that it doesn't add to compression artifacts. aptX for example will definitely add more degradations to an MP3.
 

Lunafag

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Now if only bluetooth devices supported opus instead of that proprietary codec. It even has a low latency mode. Oh well, one can dream.
 
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amirm

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faheem

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This is most impressive. Now, if only Topping would take their excellent engineering and design a portable DAC+amp that also had an outstanding Bluetooth implementation. They would not necessarily even need to come up with an entirely new design if they just stuck the guts of this into one of their existing portable devices.

Ya, The BC3 is a better alternative to the BTR5 in single ended, digital out,better implementation of handling connections to multiple devices at once and better battery life . Hopefully Topping will release a Balanced BC3 or IFI idsd Diablo competitor at some stage.
 
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PeteL

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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.
Yeah, I'd like to experience LDAC, it looks really great on paper and it leaves no doubt seeing this review it is a huge step up, wouldn't be afraid to call this hi-fidelity and quite probably indistinguishable from lossless. BUT there's optimal, and there's real life, and there is no magic, What Bluetooth is capable of transferring, and what in real life happens is not the same, again I don't know because I don't use LDAC, but for example any Bluetooth devices I've used, when switching to AptX HD which is "only" 576 kbps, the range decrease significantly, even at 3-4 meters it starts to stutter. It's not the CODEC fault, but none the less. It's great to advertise 990, but if in usage it always have to roll back to "best effort" then all that great algorithm is wasted. I don't see how it could be different than my example. I wonder the percentage of LDAC users that actually use it consistently at 990 kbps.
 

Oukkidoukki

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Can amirm test the quality of ldac with dacs also? Most of them have it built in. Is this possible? Maybe aptx hd and uat also….
 

Pdxwayne

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I can. Is there an example of a recent DAC I have tested which has it?
Gustard x16. Interesting that Gustard is not in Sony's list of approved vendors(I thought you listed that, but now it is gone from the 1st post?)

Anyway, when using best quality from about 10 ft away, I often got connection issues....
 
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dougi

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Yeah, I'd like to experience LDAC, it looks really great on paper and it leaves no doubt seeing this review it is a huge step up, wouldn't be afraid to call this hi-fidelity and quite probably indistinguishable from lossless. BUT there's optimal, and there's real life, and there is no magic, What Bluetooth is capable of transferring, and what in real life happens is not the same, again I don't know because I don't use LDAC, but for example any Bluetooth devices I've used, when switching to AptX HD which is "only" 576 kbps, the range decrease significantly, even at 3-4 meters it starts to stutter. It's not the CODEC fault, but none the less. It's great to advertise 990, but if in usage it always have to roll back to "best effort" then all that great algorithm is wasted. I don't see how it could be different than my example. I wonder the percentage of LDAC users that actually use it consistently at 990 kbps.
I have used it at a fixed 990kbps at about 4m line of sight to an iFi Zen Blue. Most of the time it is reliable, but sometimes stuttering happens for no apparent reason (no other bluetooth devices around). Of course, when the wife comes home in the car that the phone is also paired to, then all hell breaks loose for a while when it is handshaking or something.
 

Lunafag

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Most of the time it is reliable, but sometimes stuttering happens for no apparent reason (no other bluetooth devices around).
Anything working at 2.4GHz will jam bluetooth. Wi-fi, LTE, microwave ovens.
 

Bullwinkle J Moose

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I have that, don't care how well it will test it's unusable. It keeps forgetting my BTR3 and lack of physical buttons is a pain. I got it to use with my TV and headphones so I don't disturb my wife.

THAT is the problem with them

The
https://www.taotronics.com/products/tt-ba014-bluetooth-transmitter-receiver
are unreliable!

I have 2 of them

One works as advertised, and one will receive from the other but not transmit to the other

I also have the BTR-3K and they NEVER forget it unless I try to connect too many other devices

Incredible range however, and I'd rather have Low Latency with "good enough" sound quality

I can do without LDAC but cannot go a day without Low Latency
 

Francis Vaughan

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There is an ironic chicken and egg question about measuring the capability of these codecs. All of the lossy compression schemes are perceptual. They are the result of application of enormous amounts of research into the human auditory system. Understanding of the intrinsic limitations due to things like masking, critical bands and so on. Any argument about what matters in actual hearing versus simple measurements would almost certainly find that the largest body of knowledge on the subject is within the design of these codecs. Design is known to have included rigorous listening tests.
Some criticism of the early codecs was that they placed undue emphasis on classical music. (Not that I care.) But modern ones are likely wider in scope.
The reality is that once past a reasonable bit rate they are perceptually transparent. You can tell their presence, not by a reduction in sonic quality, but by listening for specific tells. Like unnatural cut-off of fade outs.

In a curious way one could regard a good perceptual codec, not as a device to try and trip up with weird and contrived waveforms, but as an Oracle. It will pass that part of a signal that is perceptually important, and stuff it doesn’t pass is the part of the signal that isn’t worth worrying about. In this manner perceptual codecs might be a useful tool in trying to bridge the gap in deciding the relative importance of distortion components.
 

don'ttrustauthority

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Where did you get that from?

I can't find it, but in looking I see that at least one site seems to say LDAC has 'lossless' compression at 990 kbps (I thought lossless was 1411 kps) which would explain the flat curve you have in the review. I didn't know it did that.
 

Francis Vaughan

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You can’t translate a bit rate to a bandwidth with a lossy codec. Nor is it possible to create a lossless compressing codec with a fixed bit rate. Lossless must be variable bit rate. Intrinsically the upper rate must always equal the uncompressed bit rate.
Lossy codecs can use any coding they feel like. You could send commands that simply list a set of frequencies and amplitudes. The bandwidth possible it thus near infinite. Possibly not the best way of doing things for audio, but for some tasks likely very effective.
 
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