limit on sampling rate for Bluetooth

Support questions for Neutron Player only (http://neutroncode.com/apps/player).
blaubär
Posts: 3442
Joined: Tue Apr 02, 2019 6:48 am

Re: limit on sampling rate for Bluetooth

Post by blaubär » Mon Feb 15, 2021 8:36 am

would it be advisable to switch high-res for BT off to make sure no downsampling occurs and Neutron Neutron does the dithering rather than the os ?
Yes, if the user is not sure then the best would be to use basic format (Hi-Res Bluetooth = Off) 16/44100 which Neutron will try to use automatically. Some firmwares (Sony devices) expose BT device in the device list with additional frequencies, like 48000, 96000, so Neutron will automatically detect it and offer to the user even if (Hi-Res Bluetooth = Off).

blaubär
Posts: 3442
Joined: Tue Apr 02, 2019 6:48 am

Re: limit on sampling rate for Bluetooth

Post by blaubär » Mon Feb 15, 2021 9:54 am

I was able to set my Sony-WH1000XM2 into what Sony calls the "high-quality-mode", meaning they use LDAC and not SBC codec. With high-res for BT enabled Neutron can now deliver 88.2 or 96 kHz sampling rate to BT. Because my tracks are sampled with 44.1 kHz and I use 2 x oversampling I get 88.2 kHz. In the developer options on my Samsung S9 I see that it's set to 96 kHz / 32 bit. I changed that to 88.2 kHz / 24 bit. That change doesn't persist though: each time I switch BT off and on I have to reset it from 96 kHz / 32 bit to 88.2 kHz / 24 bit.

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tavrouss
Posts: 26
Joined: Sat Feb 13, 2021 7:58 pm

bit rate of sound track

Post by tavrouss » Fri Feb 19, 2021 6:22 pm

Almost of my music tracks have a bit rate of 1.4 Mbps and is flac.does downsampling affects bitrate?

blaubär
Posts: 3442
Joined: Tue Apr 02, 2019 6:48 am

Re: limit on sampling rate for Bluetooth

Post by blaubär » Fri Feb 19, 2021 6:52 pm

A bit rate of 1.4 Mbps probably means CD quality : 2 channels x 44100 Hz x 16 bit = 1.411.200 bps . Now 44.1 kHz in most cases won't be downsampled - why should it ? If the device doesn't support high-res it might be upsampled to 48 kHz, that would increase the bitrate slightly. The problem with downsampling typically occurs when you've got high-res-audio and the device downsamples to 48 kHz, that will decrease the bitrate,

tavrouss
Posts: 26
Joined: Sat Feb 13, 2021 7:58 pm

Re: limit on sampling rate for Bluetooth

Post by tavrouss » Fri Feb 19, 2021 7:59 pm

Isn't mp3 also 16 bit at 44100 frequency?

tavrouss
Posts: 26
Joined: Sat Feb 13, 2021 7:58 pm

Re: limit on sampling rate for Bluetooth

Post by tavrouss » Fri Feb 19, 2021 8:05 pm

which is more quality?
1- mp3 320kbps > neutron(24 bit at 96khz) > OS > downsampling to 16 bit at 44.1 khz (quality 1)
2-flac 1.4Mbps > neutron (24 bit at 96khz) > OS > downsampling to 16 bit at 44.1 khz (quality 2)

quality 1 is better or quality 2?

blaubär
Posts: 3442
Joined: Tue Apr 02, 2019 6:48 am

Re: limit on sampling rate for Bluetooth

Post by blaubär » Fri Feb 19, 2021 8:23 pm

mp3 comes with 16 bit and 44.1 kHz or 48 kHz and a bitrate from 32 kbps to 320 kbps. It's a lossy compression, the higher the bitrate the better the quality. Most people won't hear a difference between mp3 with a bitrate above 160 kHz and anything better.
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flac is a lossless compression. If you compress the music from a CD to flac files then the bitrate stays the same 1.4 Mbps. Only the size of the files will decrease ( and bitrate in this context means bits per time of the music after it has been uncompressed again ).
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If you play mp3 or flac with 44.1 kHz sampling rate and your device supports high-res-audio, then you can upsample to a higher bitrate. But as Neutron only lets you do this if the device supports the higher bitrate no downsampling will happen.
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Theoretically the quality of mp3 is lower than that of flac, because mp3 is a lossy compression and flac is lossless. And yes, there are people who claim they hear a difference between high-quality mp3 and anything better. I don't.

tavrouss
Posts: 26
Joined: Sat Feb 13, 2021 7:58 pm

Re: limit on sampling rate for Bluetooth

Post by tavrouss » Fri Feb 19, 2021 9:09 pm

If downsampling is occured while listening from blurtooth:

1- mp3 320kbps > neutron(24 bit at 96khz) > OS > downsampling to 16 bit at 44.1 khz (quality 1)
2-flac 1.4Mbps > neutron (24 bit at 96khz) > OS > downsampling to 16 bit at 44.1 khz (quality 2)

quality 1 is better or quality 2 ???

blaubär
Posts: 3442
Joined: Tue Apr 02, 2019 6:48 am

Re: limit on sampling rate for Bluetooth

Post by blaubär » Fri Feb 19, 2021 9:49 pm

In a situation where you know that the os will downsample, but Neutron doesn't know that, and upsamples, and then the os downsamples ... then you'd better not upsample in the first place, because any benefits from the upsampled DSP processing might be scuppered by the ( compared to Neutron's standards ) undefined downsampling.
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If you upsample anyway and the os downsamples the question would still be if you're one of the very few who can hear the difference between best mp3 and CD quality. If you are ... well, perhaps then you'll also hear the difference between keeping the sampling rate and up- an downsampling.
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And in your scenario we've got the additional complication of Bluetooth, which itself might not be above mp3 quality.
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From what I hear from the people who claim they can hear that good I'd say you'll have to spend a lot of money for hardware first. Without a proper sound studio ( or comparable equipment in a comparable location ) afaik nobody ever claimed to have heard any such difference.
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And if you really can hear any difference we'd be glad to hear your feedback. Then you're the expert and decide the matter.
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Of course, from a purely technical point of view lossless is always better than lossy compression. But what's the practical benefit of this for the listener ? I don't see one.

tavrouss
Posts: 26
Joined: Sat Feb 13, 2021 7:58 pm

Re: limit on sampling rate for Bluetooth

Post by tavrouss » Fri Feb 19, 2021 10:39 pm

If you set up a 40-megapixel camera to take a 13-megapixel photo, the picture quality is better than a 13-megapixel camera that takes a 13-megapixel photo.
Because of this similarity, I asked the previous question.
I hope someone has a good answer to my previous question.

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