Skip to main content

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Realtek 48 KhZ sampling? (Read 2668 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Realtek 48 KhZ sampling?

From the ALC662 documentation here http://www.datasheetspdf.com/datasheet/ALC662.html is clear thas this codec has one 24.0 MhZ master clock and 48 KhZ sample rate support (sent in one sample and 96 KhZ in two samples etc), 44.1 KhZ is also supported natively but through ratio 147/160 and appropriate sequence of sample frames (they call it delivery cadence) - chapter 7.2.5. SImilar mechanism is found in some other realtek chips.

Questions:

1) what does the described mechanism to the sound? Is it still bitperfect play, or do Realtek chips actually resample  somewhat?
2) if it is bitperfect, does the used technique have impact on sound ? (jitter etc). 
3) Does it make quality sense on those chips to resample 44.1 KhZ to 48 KhZ e.g. by using SoX or SSRC when playing by FoobarR on the fly?

Thanks,

Jan

Re: Realtek 48 KhZ sampling?

Reply #1
I assume you're talking about playback?

Resampling can't be bit perfect (since you are altering the samples) and analog-to-digital or digital-to-analog conversion can't be bit perfect either, since there are no bits in analog.

I really wouldn't worry about it.   Resampling is almost always transparent (as long as you stay at or above 44.1kHz and 16-bits).

It's "nice" to avoid unnecessary resampling if you can, but there's usually no problem if your soundcard has to resample at playback time. 

Re: Realtek 48 KhZ sampling?

Reply #2
What if Realtek resampling at 44.1-48 KhZ is worse than Foobars SoX or SSRC ?

Re: Realtek 48 KhZ sampling?

Reply #3
What if Realtek resampling at 44.1-48 KhZ is worse than Foobars SoX or SSRC ?

It probably is worse, in order to avoid delaying the sound too much (realtime SoX resampling introduces a bit of delay), but it's very unlikely to be audible.

Re: Realtek 48 KhZ sampling?

Reply #4
Then, if realtek upsamples to 48 KhZ native rate, is maybe useful to resample through SoX and send to realtek 48 KhZ ....

Re: Realtek 48 KhZ sampling?

Reply #5
Then, if realtek upsamples to 48 KhZ native rate, is maybe useful to resample through SoX and send to realtek 48 KhZ ....

Sure, but it's exceedingly unlikely that you will hear any difference.

Re: Realtek 48 KhZ sampling?

Reply #6
You could use a 20khz tone in foobar to test.  Usually if the device isn't resampling, you won't hear anything (or very little).  If it is resampling, it'll become much louder away from the fixed sampling rate (usually 48khz).

Re: Realtek 48 KhZ sampling?

Reply #7
I cannot hear 20 KhZ, my reliable hearing (yes/no saying) is at 16-17 KhZ max ...

Re: Realtek 48 KhZ sampling?

Reply #8
So what, then, was all the fear about noise-shaped dither and unsolicited bumping of discussions with your dither of choice and a TOS8 violation?

Re: Realtek 48 KhZ sampling?

Reply #9
I cannot hear 20 KhZ, my reliable hearing (yes/no saying) is at 16-17 KhZ max ...

Then it should be very easy for you to test for bad resampling, as you will hear nothing without it.

Re: Realtek 48 KhZ sampling?

Reply #10
Quote
Then, if realtek upsamples to 48 KhZ native rate, is maybe useful to resample through SoX and send to realtek 48 KhZ ....
SoX is known to measure  as a good resampler, but it's NOT known to sound  better than any random-average resampler (in a proper-scientific blind listening test).

If it makes you feel better, go ahead and use SoX.  ;)

Or if you want to be paranoid, get a DAC or interface that supports a variety sample rates.  Then make sure your device's drivers support WASAPI exclusive mode, or get an application and interface that supports true ASIO.   


Re: Realtek 48 KhZ sampling?

Reply #12
Sorry for disturbing.
I am already using WASAPI exclusive, my realtek codecs support 44.1,48,96 KhZ, but 44.1 with the technique I described.

Using SoX seems to be good alternative to internal technique.

Re: Realtek 48 KhZ sampling?

Reply #13
Using SoX seems to be good alternative to internal technique.
Based on what evidence?!?

Seriously, stop with the nonsense!

Re: Realtek 48 KhZ sampling?

Reply #14
To the hearing, I do not play only for myself but also for others members of our home. So strictly deciding by "hear/cannot hear at my 16-17KhZ ears" is kind of pointless, and generally I would like to play at the good quality regardless of what can be "exactly" heard or not. When making photos also you dont make bad quality saying that people have old LCDs.

If it makes problems, I can stop with this thread and keep trying on my own ...


Re: Realtek 48 KhZ sampling?

Reply #15
That would be a good idea.

Discussion closed.

I will be happy to re-open if someone can, in keeping with our terms of service, demonstrate an audible problem with the resampler in question.