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
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
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
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??

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