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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: balou2 on September 04, 2007, 03:01:16 AM

Title: Dither and sample issues - Can that slow down a recording?
Post by: balou2 on September 04, 2007, 03:01:16 AM

So I pulled a 24/48 file a couple weeks back and did the normal thing.  Dithered to 16 in Sound Forge and resampled in the same.  I compared my recording to another source, and mine is noticeably slower.  Can resampling and/or dithering slow the pitch?

My rig>
Vintage Gefells > V3 > R4 (24/48)

My recording: http://www.archive.org/details/hbr2007-08-19.gefell.flac16 (http://www.archive.org/details/hbr2007-08-19.gefell.flac16)

The other source was Will_S's LSD2>Presonus Firebox>Rockboxed iRiver

Will's recording:  http://www.archive.org/details/hbr2007-08-19.LSD2.flac16f (http://www.archive.org/details/hbr2007-08-19.LSD2.flac16f)

We were set up only inches apart, yet the difference is noticeable.


I'm a bit confused on this, as I can't image the clock being that different in the two recorders.  Any ideas?
mike

Title: Re: Dither and sample issues - Can that slow down a recording?
Post by: balou2 on September 04, 2007, 03:02:11 AM

btw, I didn't use any of the specific dither metrics...just the "zero" or "normal" one. 

Title: Re: Dither and sample issues - Can that slow down a recording?
Post by: boojum on September 04, 2007, 03:13:11 AM

I can tell you only that this has never happened to me using Audacity, CoolEdit or Samplitude V8 LE. 

1) does your recording pitch sound off??

2) could the other recording be noticeable faster??

3) have you compared the original (before resampling and dithering) recording to the other fellow's??

Title: Re: Dither and sample issues - Can that slow down a recording?
Post by: Belexes on September 04, 2007, 09:13:49 AM

I just recorded Joe Bonamassa in 24/48 and when I dithered down to 16/44, the recording slowed down as well. I used Cool Edit Pro 2.0.

So I am in the same boat.

Title: Re: Dither and sample issues - Can that slow down a recording?
Post by: bgalizio on September 04, 2007, 09:18:01 AM

I think the resampling is to blame. Once I had an issue with Audacity not resampling, but just changing the header. It sounded slow and tuned down. Make sure your resample is happening properly (ie: start with 24/48, resample to 24/44.1 and listen), as I'm thinking that's the problem.

To clarify, it was my own user error that caused the resampling/header issue with Audacity. And, I can't listen to your files here - just going off my own experience with a slow sounding recording.

See this thread for more information:
http://taperssection.com/index.php/topic,80888.0.html

Title: Re: Dither and sample issues - Can that slow down a recording?
Post by: Jhurlbs81 on September 04, 2007, 12:33:17 PM

http://taperssection.com/index.php?topic=80888.0 (http://taperssection.com/index.php?topic=80888.0)

Title: Re: Dither and sample issues - Can that slow down a recording?
Post by: j5brock on September 05, 2007, 10:37:06 PM

I recently normalized and dithered and resampled in audacity..and somehow managed to change the sample rate on the project rather than resample.. it added about 8min to an hour and a half set..definately slowed down and changed the pitch..maybe something similar has happened here.. have you checked the full file playing time master versus post?

Jeff

Title: Re: Dither and sample issues - Can that slow down a recording?
Post by: todd e on September 07, 2007, 09:27:54 AM

forgive me if this sounds odd, but why would you dither before your resampled?

i always thought you take the 24/48 or 24/96, resample (not just change the sample rate, but use a tool that resamples)
and from there, dithered as you saw fit.

Title: Re: Dither and sample issues - Can that slow down a recording?
Post by: Belexes on September 08, 2007, 12:31:02 AM

I went to here and I am still lost:
http://taperssection.com/index.php/topic,80888.0.html

I "adjust sample rate" in Cool Edit Pro from 48 to 44 and that is when the recording slows down. What am I doing wrong?