Quick DAT > HDD question

[Massive Dynamic]

I just started doing DAT to hard drive transfers, playing 48k masters on R300 > optical > iRiver H120 > USB > iMac G5. Although the wav files sound fine, I noticed that the time of the wav files is longer than on DAT, e.g., a 97 minute show on DAT will result in a 105 minute wav file. Is this just a clock issue, or something more serious? Do I need to do anything to the wav files to "correct" them? Thanks.

[Brian Skalinder]

How do transfers sound?  Do they sound too fast or too slow?  Just a guess, but I bet the transfers don't sound right.  Here's why:

The ratio of 44.1 kHz to 48 kHz is the same as the ratio of your differing recording lengths, 97min to 105-min:  0.91875:1   (Well, not precisely, but I'm assuming you're rounding the lengths to the minute, rather than listing precision to the seconds values.  In other words, a 97-min 48 kHz file played back at 44.1 kHz will run for 105-min.

This doesn't seem like a coincidence to me.  I'd check to see if the transfers play back at proper speed.  I'm guessing the transferred files' WAV headers are set to 44.1 kHz while the data remains at 48 kHz.  This would account for the longer run-time of the transferred WAVs relative to the DATs.

[Massive Dynamic]

Thanks, Brian, as usual I think you've nailed the problem.  +T
I actually searched this time and found another thread where someone had the exact problem.
http://taperssection.com/index.php/topic,72076.0.html

To fix the files, do I just set the sample rate to 48k in Audacity and re-save? Should I track first? I did change the sample rate to 48k on a 1GB file, and exported to wav. Took about 3 minutes. Did I actually resample, or just change the header?

[Brian Skalinder]

To fix the files, do I just set the sample rate to 48k in Audacity and re-save? Should I track first? I did change the sample rate to 48k on a 1GB file, and exported to wav. Took about 3 minutes. Did I actually resample, or just change the header?

Depends on what you mean by "set the sample rate".  Two ways to do this:

• Track (black upside-down triangle dropdown next to track name) | Set Rate | <select rate> will change the WAV header, but not resample.
  
• Project Rate button | <select rate> will resample.
  
  

General workflow info for Audacity.

[Massive Dynamic]

Well, I tried every possibility and came up with results opposite of what I would have guessed. I am a total newb with Audacity and computer editing, so I really don't know what to think. Is it really possible to change just the header in Audacity without resampling?

Depends on what you mean by "set the sample rate".  Two ways to do this:

• Track (black upside-down triangle dropdown next to track name) | Set Rate | <select rate> will change the WAV header, but not resample.
  
• Project Rate button | <select rate> will resample.

On a 1.03 GB file, I set the sample rate to 48k using both the track and Project Rate, and exported to wav. Took about 3 minutes and ended up with a 1.03 GB file. Track time changed from 1:44 to 1:36, was 48k and sounded fine.

• Track (black upside-down triangle dropdown next to track name) | Set Rate | <select rate> will change the WAV header, but not resample.

On the same 1.03 GB file, I set the sample rate to 48k using only the track option, and exported to wav. Took about 12 minutes and ended up with a 968.2 MB file. Track time showed 1:36, was 44.1k and sounded fine.

• Project Rate button | <select rate> will resample.

On the same 1.03 GB file, I set the sample rate to 48k using only the Project Rate, and exported to wav. Took about 10 minutes and ended up with a 1.12 GB file. Track time still showed 1:44, was 48k and sounded slow.

[Brian Skalinder]

Well, I tried every possibility and came up with results opposite of what I would have guessed. I am a total newb with Audacity and computer editing, so I really don't know what to think. Is it really possible to change just the header in Audacity without resampling?

Pretty darn sure.  Maybe I got mixed up in my previous post.  I'll try to check this weekend.

[Brett S.]

Iriver h120>usb

Forgive me for I could be wrong. I am just interested as well!

But does the h120 support 48khz? If not then the unit maybe resampling down to 44.1 before it even gets to hdd(Audacity).

Appears as if you are using the iriver for your soundcard which problebly would work if you were going dat 44.1>h120 dig pass>usb> hdd.