Can I un-equalize it?

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mewalden
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Can I un-equalize it?

Post by mewalden » Thu Mar 03, 2011 9:23 pm

I have a bakelite 78 which was recorded (cut) at Grinnel's music store in Detroit in 1951- I don't know what kind of machine did it. This method of personal recordings was popular then.

To input the audio to my Windows Vista system, I used a Behringer UFO202 U-Phono device to USB, audio codec, and I have it set for phono processing- tape setting won't work because the volume is extremely low.

I used a 33 1/3 and 45 turntable, I don't have a 78 turntable. I used Audacity to change the speed to 78- that feature seems to work nicely.

As I understand it, the Behringer output is equalized through its pre-amp. I don't think the record was cut with equalization. The resulting mp3 sounds OK, but my ear is not that precise.

So, is it possible to "undo" the equalization that the UFO pre-amp does?

billw58
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Re: Can I un-equalize it?

Post by billw58 » Thu Mar 03, 2011 9:38 pm

You've stepped into a complex topic. http://manual.audacityteam.org/man/Reco ... pm_records

The short answer is, yes, you can undo the RIAA EQ applied by the pre-amp. The bad news is that you should do that before you correct the speed. Do you have the original Audacity recording before you corrected the speed?

If you don't have the original Audacity recording, you have three options:
1) Record the 78 again, then reverse the RIAA EQ as described in the tutorial.
2) Change the speed back to the original, reverse the RIAA EQ, then change the speed back to normal. (Not great since it involves two more speed changes which may degrade the sound quality).
3) Use Brian Davies' free "Equalization" program to adjust the EQ without needing to change the speed back to the original recording.
See http://www.clickrepair.net/equalization.html

-- Bill

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