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Re: Sample Rate Conversion

Subject: Re: Sample Rate Conversion
From: "Rich Peet" <>
Date: Sun, 09 May 2004 14:05:56 -0000
Ok, I have listened to each and rated them.

1. Adobe Audition 1.0
2. Spark
3. Shak
4. Peak

What surprises me is that a Windows program won.

Rich Peet
ps. I can hear the bat that I posted.

> 
> I've put up what I got off a copy of Lang's file:
> Peak 4.03:
> m("44khz_peak.aif","//madranis.home.mindspring.com/insect");">http:
> Spark XL 2.81:
> m("44khz_spark.aif","//madranis.home.mindspring.com/insect");">http:
> Soundhack (osX version 0.892):
> m("44khz_shak.aif","//madranis.home.mindspring.com/insect");">http:
> The original Lang sent me:
> m("4","//madranis.home.mindspring.com/insect");">http:...
> 
> I should note I also found a slight DC offset in the original, and
> removed that before conversion. DC offset introduces it's own 
errors and
> I routinely remove that.
> 
> Also, my system only outputs at 44k, so even listening to the 
original
> it was already resampled. Spark and Peak played the original the 
same.
> Sonograms showed in addition to the high frequency call centered on
> about 12khz a band at about 5khz (the raspy sound) and a bunch of 
low
> level sound below 170hz. The sonogram of the peak conversion does 
show
> some very low level sound below the 5khz band.
> 
> Spark has batch capabilities, soundhack does not. I used best 
settings
> in each, Spark was doing the math in 32bit floating point, not 
sure on
> the others. Each has variations in settings available, and those do
> change the outcome.
> 
> I have such lousy hearing at these high frequencies I was having to
> really boost volume. To me Peak and the original sound about the 
same,
> but that could be my hearing. Spark is different. I also did 
Soundhack
> as well, somewhere between peak and spark. I had my son listen to 
them
> all, he can listen to the high frequency at normal listening 
settings.
> He said there was little difference to him.
> 
> Walt
> 



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>From   Tue Mar  8 18:27:14 2005
Message: 8
Date: Sun, 09 May 2004 14:57:11 -0400
From: Walter Knapp <>
Subject: Re: Best Transfer method

From: 
> 
> Please!
> 
> Which is the better way to transfer data into one's computer:
> 
>     1. Optical
>     2. Coaxial
>     3. USB
> 
> If USB is not an option is there any difference in the results in using 
> Optical or Coaxial? I am talking about Real Time transfers.

My preference is optical.

I've used all three transferring from my Portadisc. For Coax & Optical 
always into the Roland UA-30, which means that those are also actually 
transferred via USB. All three work just fine for me.

My routine transfers are via optical. I prefer this method as the 
Portadisc is then electrically isolated from the computer. No chance of 
odd stuff from ground loops or whatever. In addition that sets the 
Roland up to be a two way monitor without having to rewire anything. 
Older USB setups had a problem where the OS would keep both in and out 
attached to the USB, making a problem for monitoring. Newer controls 
allow setting them separate.

Note all my stuff is running 44khz sampling, and the actual sampling was 
done when the Portadisc recorded the material and is digital from there 
on. So, I don't deal with sample rate conversions very often, and never 
in my main system.

The Roland UA-30 follows the USB protocol in transferring audio into my 
computer. That audio protocol is 44khz. The Roland can take a 48khz 
input, but must provide it's own conversion. I'm not sure how widespread 
this limitation is in USB "soundcards", but if working with sample rates 
other than 44khz and using a USB device you need to verify it's limitations.

It's also worth verifying what the coax is doing too. Coax is more 
associated with 48khz sampling rates, so if inputting 44khz digital you 
may have a situation where your digital gets resampled twice getting in. 
This was definitely true of some PC soundcards.

Walt




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>From   Tue Mar  8 18:27:14 2005
Message: 9
Date: Sun, 09 May 2004 15:01:09 -0400
From: Walter Knapp <>
Subject: Re: Best Transfer method

From: Aaron Ximm <>

> Unless anyone has heard of one medium being more prone to problems?

There are little quirks in each one. Rarely cause problems.

> FWIW it's much easier and cheaper to find coaxial SPDIF cables than long
> optical ones, though maybe that's changed since aren't they used for
> consumer 5.1 now?

I use a 6' optical cable, and have a 12' one. I've seen 20' ones. That 
should be plenty long enough. True digital coax seems rarer around here 
than the optical ones.

Walt




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