Topping BC3 Review (Bluetooth Receiver) & BT CODECs

[B4ICU]

I'm missing the Analog output in all aspects:
Fr. curve, Distortion and Power to drive low impedance / high impedance HP and more.
If you need a Ref. of what I'm complaining about, just go to a standard HP Amp. test...
Yes, all that is missing.
What about listening else than LDAC Codec ?

 

[daftcombo]

This is a bluetooth receiver and doesn't do any wifi/multi-room stuff like the Chromecast audio does.

Yes but if your source is 1m away from the device, being BT or WiFi, what would you choose?

 

[xarkkon]

saw the panther and thought, "What? Topping missed the mark?!"

didn't realise it was actually a good review. phew!

 

[LTig]

The file is not the issue. The issue is AP software being able to run that way asynchronously. For some tests it can, for others it cannot.

Pity. However you could skip AP completely and use REW in combination with your RME ADI-2 PRO with (I think) no loss in precision if you use its TOSLINK input. Of course this is more work for you ...

 

[amirm]

Pity. However you could skip AP completely and use REW in combination with your RME ADI-2 PRO with (I think) no loss in precision if you use its TOSLINK input. Of course this is more work for you ...

REW doesn't have any of the controls than AP software has. I can run the chip sweeps in AP just like it is done in REW. But you can't get things like distortion versus level sweeps.

 

[nhatlam96]

Switching to AAC shows the poor quality. We get a big boost in SINAD but I am not happy about all the artifacts. In my prior testing I found SBC to actually sound better.

AAC has 83 SINAD and SBC has 70 SINAD, how can AAC still sound worse? How audible are those artifacts? For AAC I can see that it is going a little crazy above 2k, but it's still around -110, so shouldn't be a problem?

 

[xthechar]

These measurements are great to finally see. Would be very interested to see graphs for:

• aptX HD
• LDAC at 330 explicitly
• LDAC at 660 explicitly
• LDAC at 990 explicitly
• LDAC at adaptive while walking a decent distance away from the receiver

 

[CRKebschull]

These measurements are great to finally see. Would be very interested to see graphs for:

• aptX HD
• LDAC at 330 explicitly
• LDAC at 660 explicitly
• LDAC at 990 explicitly
• LDAC at adaptive while walking a decent distance away from the receiver

This is a very important point.

The S/N of LDAC 330 is much less than LDAC 660 which is much less than LDAC 990.

This page The ultimate guide to Bluetooth headphones: LDAC isn’t Hi-res indicates, for example, that LDAC 330 has a worse S/N than SBC.
That look at LDAC uses reference material from Robert Triggs from Android Authority from this article: What you need to know about Sony's LDAC

Perhaps to summarize those articles: "At CD quality, LDAC 990kbps and 660kbps are a touch better than aptX HD, yet both require even more bandwidth." Which would seem to indicate that the RANGE of LDAC 990 or LDAC 660 is less than that of AptX-HD.

Further the article concludes "Ultimately, LDAC users are likely to spend a fair bit of time listening to the 330kbps version. Unfortunately, the available resolution and 18kHz cut-off frequency are objectively inferior to CD quality, Qualcomm’s aptX, and SBC. "

So it is entirely relevant what bitrate LDAC you can connect with, and if that bitrate is stable enough with your equipment to be usable for you.

From my own experience: With my Qudellix 5K (tested positively here on ASR) and my Pixel 3A with Android 11, I can get LDAC 990 only within maybe a meter of the phone (in my real life listening environment). In fact, in the Android developer settings of the phone, the actual bitrate is typically never more than 440kbit, I can force this to 660 and maybe get a stable connection, and I can try 990kbit so long as I don't move my head at all if I don't want to have the connection lost.

 

[lizhuoyin]

It's claimed in ldac wiki that it's lossless with 16bit/44.1kHz/990kbps settings for CD.

 

[CRKebschull]

It's claimed in ldac wiki that it's lossless with 16bit/44.1kHz/990kbps settings for CD.

Marketing lies? From the article I cited in my reply above (graph also from the SoundGuys Article):

"[...]the bottom line is that Sony’s LDAC technology doesn’t really provide true Hi-Res audio over Bluetooth. Technically, the 990kbps version of the codec reaches all the way to 48kHz (and is the only codec able to do so). However, its resolution and noise floor are nowhere near 24-bits, and are worse than 16-bits above 15kHz. "

 

[LTig]

REW doesn't have any of the controls than AP software has. I can run the chip sweeps in AP just like it is done in REW. But you can't get things like distortion versus level sweeps.

You mean like this measurement behind the spoiler here? I'll check later how I did it, but REW not long ago got the feature to do level steps.

 

[lizhuoyin]

Marketing lies? From the article I cited in my reply above (graph also from the SoundGuys Article):

"[...]the bottom line is that Sony’s LDAC technology doesn’t really provide true Hi-Res audio over Bluetooth. Technically, the 990kbps version of the codec reaches all the way to 48kHz (and is the only codec able to do so). However, its resolution and noise floor are nowhere near 24-bits, and are worse than 16-bits above 15kHz. "

View attachment 132224

I am satisfied with lossless CD quality @ 16bit/44.1kHz. HiRes is a marketing lie to me for listening.

 

[thefsb]

Wow! What an improvement. Then again, all the other codecs should have done excellently with this simple sine wave that is dead easy to encode.

Which makes me wonder if the performance of LDAC with a 1 kHz tone is representative of its performance with more complex signals, especially musical ones.

Lossy compression is fairly complex software. So, in the extreme, the software could be designed to perform especially well under known standard test protocols. We've seen this for example in the design of engine management software for cars. You could design a lossy codec that performs transparently with test tones, including sweeps and multi-tone tests, at very low bit rate.

I'm not suggesting that LDAC is designed to deceive such tests, although that's possible. High performance given signals that have a low information rate (such as those used by ASR) could possibly be an artifact of a lossy codec highly optimized using phsychoacoustic models to encode music at low bit rates.

You don't test voice codecs using sine tones, you use subjective ineligibility tests. How much sense then does it make to evaluate a lossy codec optimized for subjective quality at low bit rates with music signals by seeing how it performs with test tones?

 

[JohnBooty]

Great review!

Looking forward for the iPhone AAC test because that is all what us Apple bleeps get to use.

I'm definitely frustrated by this too. I've tried a few AAC-supporting headphones and have not enjoyed the sound quality. Given the upcoming lossless upgrades for Apple Music, I would expect them to start supporting higher quality BT codecs at some point. Hopefully they can work something out with Sony and use LDAC rather than rolling their own.

While obviously not a feasible alternative to Bluetooth in a lot of situations like headphones and such, for those in the Apple ecosystem it's always worth remembering that AirPlay is lossless and Apple's Airport Express dongles have very decent analog output performance + optical output: https://www.kenrockwell.com/apple/airport-express-audio-quality-2014.htm

While sadly discontinued, Apple sold a zillion of them so they're cheap and plentiful on eBay: https://www.ebay.com/sch/i.html?_from=R40&_nkw=airport+express&_sacat=0&rt=nc&LH_Complete=1

There are open-source implementations of AirPlay as well, so using it doesn't lock you into Apple gear or anything. Last I checked it was easy to set up a RaspberryPi for this.

 

[JohnBooty]

You don't test voice codecs using sine tones, you use subjective ineligibility tests.

Are there objective and repeatable psychoacoustic benchmarks for lossless lossy audio codecs?

I *think* the equivalent exists for video codecs but I'm not sure...

edit: corrected "lossless" to "lossy"

 

[Oukkidoukki]

Thanks. It was fun for me too discovering new things. I have another Bluetooth receiver to test as well.

Amirm, one intresting test would be stream audio from smartphone via usb to dac Vs. Usb from pc. Does sinad or others parameters change when measured from dac xlr output?

 

[markanini]

Are there objective and repeatable psychoacoustic benchmarks for lossless audio codecs?

I *think* the equivalent exists for video codecs but I'm not sure...

LDAC is not an exclusively lossless format. On lower bitrates it's operation is related to ADPCM or Wavpack hybrid's scheme which modulates the noise floor according to the input and chosen bitrate.

 

[thefsb]

Are there objective and repeatable psychoacoustic benchmarks for lossless audio codecs?

I *think* the equivalent exists for video codecs but I'm not sure...

I think they would have to be subjective listener panel tests. Expensive and time consuming but reasonable if you're investing in a new codec that you want the industry to accepted as a new standard. That's what's needed to compare one lossy music codec with another and it wouldn't be ASR's job.

I don't think you can infer the relative subjective performance of different lossy music codecs by comparing their performance with a 1k sine tone. Iow, what we see with a 1 kHz tone doesn't mean that LDAC sounds better with music. Maybe LDAC does sound better, idk, but that test doesn't imply it.

Bench tests (that e.g. ASR could use) may be possible that characterize the performance of a device that incorporates a given codec in terms of deviation from the performance of the codec's reference implementation. Idk, just speculating now.

 

[Billy Budapest]

He is in training. He is not sure what role he wants to play when he grows up....

I think it’s a “just missed the mark” panther because he missed the pan while flipping the egg.

 

[SEKLEM]

So I've got some dumb dumb questions, I'm a smooth brain audio guy.

With Apple coming out with lossless audio next month for Apple Music I assume any Bluetooth implementation would be a bottleneck. Question is would I be able to get CD level quality with a Bluetooth device such as or similar to this?

My receiver is pre-HDMI so the AppleTV 4K is run through the television and optical to the receiver. The AppleTV will be supporting the lossless audio update in June, but I really hate having the television being on while I listen to music. I can at the very least turn the display on the TV off and use Airplay to cast from my iPhone to the AppleTV. Ideally I'd prefer to get a device that allows me to bypass the television all together that I can control with the iPhone that doesn't cost $500 that will allow me to tap into the Apple Music lossless audio. Is this device from Topping a viable option?