Quick Q for PC resampling users
May 9, 2004 at 11:59 AM Thread Starter Post #1 of 14

bangraman

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I've noticed a lot of you using 96Khz data with 96khz-compatible cards. I was under the impression that this was being done in hardware or by the soundcard drivers -> soundcard hardware... am I right in saying that what you're actually doing is using Foobar to resample?
 
May 9, 2004 at 12:03 PM Post #2 of 14

fewtch

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Quote:

Originally Posted by bangraman
I've noticed a lot of you using 96Khz data with 96khz-compatible cards. I was under the impression that this was being done in hardware or by the soundcard drivers -> soundcard hardware... am I right in saying that what you're actually doing is using Foobar to resample?


Yes, or (more correctly) using a resampling plugin. The resampling is done realtime "in software" before the data is sent to the card. The benefits of having a ~ 2 gigahertz CPU to do this should be obvious
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May 9, 2004 at 12:24 PM Post #4 of 14

fewtch

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Quote:

Originally Posted by bangraman
Thanks. I was somewhat incredulous about that but I began to have a nasty suspicion that might be the case.


How come you were incredulous? A PC is about the best general-purpose data processor there is... before digital (music) hits a DAC it's purely 1's and 0's like any other kind of data. Makes no difference at all whether it's upsampled by dedicated hardware or a Pentium 4/Athlon running a program to do it, so long as the program is a good one.
 
May 10, 2004 at 1:29 AM Post #7 of 14

adhoc

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OT WARNING:

a bit confused abt a lot of things here -

1. say, i wish to use a card's digital out to an external dac, if i resampled to 96/24 from 44.1/16, would this come out of my digital out?

2. and would i need a dac that could handle 96/24 to decode that bitstream? or would any dac do?

3. jitter - i know what it is, but i dont know what it is caused by. from what i gather, it is a result of transport and stability issues. then how can a perfectly stored digital copy of a cd (ie in wav format) possess jitter when sent out of a card's digital out??

confused.gif
confused.gif
 
May 20, 2004 at 4:06 AM Post #8 of 14

fewtch

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Quote:

Originally Posted by adhoc
OT WARNING:

a bit confused abt a lot of things here -

1. say, i wish to use a card's digital out to an external dac, if i resampled to 96/24 from 44.1/16, would this come out of my digital out?



If the software plugin doing the upsampling sent it to the card's digital out, yes.
Quote:

2. and would i need a dac that could handle 96/24 to decode that bitstream? or would any dac do?


You'd need a DAC that could handle 96/24 (if that's what you were upsampling it to).
Quote:

3. jitter - i know what it is, but i dont know what it is caused by. from what i gather, it is a result of transport and stability issues. then how can a perfectly stored digital copy of a cd (ie in wav format) possess jitter when sent out of a card's digital out??

confused.gif
confused.gif


It would mostly be due to the card's internal clock not being as accurate as it should.
 
May 20, 2004 at 4:07 PM Post #9 of 14

amol

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You need to have something like a 1ghz cpu for resampling at 96 khz slow mode, and a 2 ghz cpu for resampling at 192 khz. This is with 32 bit and strong noise shaping.
 
May 20, 2004 at 5:16 PM Post #10 of 14
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Quote:

Originally Posted by amol
You need to have something like a 1ghz cpu for resampling at 96 khz slow mode, and a 2 ghz cpu for resampling at 192 khz. This is with 32 bit and strong noise shaping.


You should specify that you mean a 1GHz or 2GHz INTEL CPU, since an Athlon XP, even turned down to about 1GHz can still upsample to 192 in real-time.
 
May 22, 2004 at 6:03 AM Post #11 of 14

adhoc

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Quote:

Originally Posted by fewtch
If the software plugin doing the upsampling sent it to the card's digital out, yes.

You'd need a DAC that could handle 96/24 (if that's what you were upsampling it to).

It would mostly be due to the card's internal clock not being as accurate as it should.



thanks for the answers fewtch - now you've piqued my curiosity. do you have any links for me to start reading up on DACs? googling only gives me tons of technical papers presentations, adverts etc
frown.gif


basically what i'm curious abt is how upsampling can actually help - so far i have the impression that it somehow reduces the noticeablilty of or negates jitter to some extent.


Quote:

Originally Posted by amol
You need to have something like a 1ghz cpu for resampling at 96 khz slow mode, and a 2 ghz cpu for resampling at 192 khz. This is with 32 bit and strong noise shaping.


oh dont you worry abt that - i have more than enough ghz handy.
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May 22, 2004 at 6:10 AM Post #12 of 14

Edwood

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Quote:

Originally Posted by Iron_Dreamer
You should specify that you mean a 1GHz or 2GHz INTEL CPU, since an Athlon XP, even turned down to about 1GHz can still upsample to 192 in real-time.


More accurately the old P4 core.

Pentium M's are far more efficient. Although, they are few and far between for desktop boards.

-Ed
 
May 22, 2004 at 4:50 PM Post #13 of 14
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Quote:

Originally Posted by Edwood
More accurately the old P4 core.

Pentium M's are far more efficient. Although, they are few and far between for desktop boards.

-Ed



Well yeah, smartass
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I guess as one of the few guys that's got one, you can acutally say that.

Of course I didn't even bring up the Athlon64/Opteron
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May 28, 2004 at 4:56 AM Post #14 of 14

skitlets

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im jealous of u rich folks with money to talk about having 64bit chips and dothan cores. im gonna be stickin with my trusty oc'ed tbred-b
 

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