Recording 33 1/3 LPs at 78 RPM

[sredmyer]

Bill, thank you for that very clear answer...and yes you did talk me out of it.

Despite the fact that I have been "talked out of it", I am still a bit confused by the RIAA EQ thing. I understand that the curve applied during mastering was based on the normal playback speed what I do not understand is why that would not be "made right" again by the speed changing software. Since the EQ is built into the recorded audio would it not still be there, correctly, when the audio data was slowed back down?

As I said you did completely talk me out of doing this I am just curious on this point.

Thanks,
Steve

[kozikowski]

The equalizer inside the turntable assumes each tone coming from the record needs its own special, specific processing. If you play the record at the wrong speed, all the tones are in the wrong place.

You're going to ask, why don't I play the record without the equalization and do the whole thing in post production. Yes, that's the only way this would come even close to working.

Unfortunately, the connection from the needle is very special, too, and you can't just jam the cartridge wires into your computer or music amplifier.

Koz

[sredmyer]

The equalizer inside the turntable assumes each tone coming from the record needs its own special, specific processing. If you play the record at the wrong speed, all the tones are in the wrong place.

Is this EQ done by the TT or by the pre-amp? This is exactly what I was asking a previous poster. He made the point (and it makes sense to me) that in my cheap-o TT (a Memorex 2650MMO) with it's USB output, EQing was probably not included.

You're going to ask, why don't I play the record without the equalization and do the whole thing in post production. Yes, that's the only way this would come even close to working.

Unfortunately, the connection from the needle is very special, too, and you can't just jam the cartridge wires into your computer or music amplifier.

Koz

Nope, I was not going to ask that one...I truely have been talked out of this by Bills excellent explanation of the problems with doing it.

[billw58]

my cheap-o TT (a Memorex 2650MMO) with it's USB output, EQing was probably not included.

Every USB turntable includes RIAA playback EQ. This playback EQ is actually done in the phono pre-amp stage. A USB turntable must include a phono pre-amp to a) apply the proper playback EQ, and b) boost the tiny signal from the cartridge so that the analog-to-digital converters have a large enough signal to work with.

I understand that the curve applied during mastering was based on the normal playback speed what I do not understand is why that would not be "made right" again by the speed changing software.

This is a tough one to get your head around, I admit. The playback EQ is applied before the sound gets into Audacity. When you slow down the recording in Audacity you also shift the EQ down by the same amount. So the EQ is effectively applied to the wrong frequencies. Put another way, it's like you applied a different EQ curve on playback.

One way to get the EQ right is like this.
1) Play back at double speed (or whatever) and record into Audacity. RIAA playback EQ is applied and there's nothing you can do about it.
2) In Audacity, reverse the RIAA EQ. Now you have a "flat" un-equalized copy of the record.
3) Adjust the speed to normal.
4) Apply the normal RIAA playback EQ.

-- Bill

[sredmyer]

Every USB turntable includes RIAA playback EQ. This playback EQ is actually done in the phono pre-amp stage. A USB turntable must include a phono pre-amp to a) apply the proper playback EQ, and b) boost the tiny signal from the cartridge so that the analog-to-digital converters have a large enough signal to work with.

Ah, well that makes sense then.

I understand that the curve applied during mastering was based on the normal playback speed what I do not understand is why that would not be "made right" again by the speed changing software.

This is a tough one to get your head around, I admit. The playback EQ is applied before the sound gets into Audacity. When you slow down the recording in Audacity you also shift the EQ down by the same amount. So the EQ is effectively applied to the wrong frequencies. Put another way, it's like you applied a different EQ curve on playback.

Ok, I think I get it.

[kozikowski]

All this has been assuming you're going to get a crisp, clear, clean, perfect playback on your USB turntable.

No, probably not. One of the other elves got one and was so disappointed with the playback he put it in the garage and dug out his old conventional turntable and brought it back to top operation to do his transfers. My semi-pro turntable has never been out of operation.

Koz

[waxcylinder]

One of the other elves got one and was so disappointed with the playback he put it in the garage and dug out his old conventional turntable and brought it back to top operation to do his transfers.

Actually ..... he managed to sell it to one of his friends who is less fussy about audio quality and places a higher value on convenience/ease-of-use.

WC