Choppy Tones for soundcard calibration

[Hollow246]

All the tones that REW generates are extremely choppy. I recently installed REW on a homemade pc running windows vista 64 bit. I have ran this program on mac before and that's how i know that the tones don't sound anywhere near like they should and is messing up the calibration process.

My chain is an A&H zed 420 mixer -> Audiofire 12 firewire-> Vista
I took the mixer out of the chain and the choppiness still occurs. I have also uninstalled and reinstalled REW as well as tried other analog inputs and outputs on my interface. I have been using this interface for a long while running sonar. It records and plays back just as it should. During normal playback from my DAW the choppiness is not an issue.

From what I gather, its either a external software problem affecting the sound REW generates or something is not set up correctly with my interface as how it plays back sounds from the os. Can anyone offer any insight on this?

Ill try to post a graph of what the calibration looks like. I forgot to copy it over while I was at the studio. The graph consists several close peaks of every frequency spanning about 20 db if not more. It looks like how a 5 year old might color in a coloring book.

[brucek]

We've seen this problem before, and there appear to be a variety of reasons.

The signal is being interrupted for some reason. It can be from other programs or processes, or can be a challenged CPU.

Have you tried different REW buffer sizes?

brucek

[Hollow246]

My apologies if this is a similar post to another thread. I thought I did a through enough search. Changing the buffer size did not help or worsen the problem and my cpu usage is only at 4% when the tones are running.

Something I did notice though was when I turned my interface on, it's start up sound has the same choppy distortion as I've been hearing on REW. I never noticed it before. I just thought that was the way it was supposed to sound hahaha

[Hollow246]

"impulse peak is not where it should be,
the measurement may have been corrupted"

Here is what's happening. I'm still convinced this is a sound card issue, but that's just my non professional opinion. I contacted the interface company but they are proving to be as useless as a lock on a screen door (there are other problems than just this). But more suggestions are always welcome. Thanks

[Hollow246]

Every calibration is different in measurement but has the same look to it

[brucek]

Did you try running REW using the internal soundcard on the motherboard as a test to ensure it's associated with firewire card?

brucek