Gain control

[oldalaskan]

I'm using 10.5.8 on a Macbook Pro. I'm running my turntable thru an ADS RDX-150 Instant Music analog-digital converter that feeds into my USB port. In Audacity 1.3.13 (and an earlier version) the input is clipping but adjusting the gain with the gain sliders has no effect. I have selected the Audacity Input Device as USB Audio CODEC. I have set the Apple system pref sound Input as USB Audio CODEC. What am I doing wrong?

[steve]

If the ADS RDX-150 does not have an input level control and it is clipping, then you need to reduce the level of the signal that is going to the ADS RDX-150.
I'm curious why you are using this device - I thought that most Macs had good quality line level inputs built in (I'm not a Mac user).

[kozikowski]

http://kozco.com/tech/audacity/pix/MacLine-In.jpg
http://kozco.com/tech/audacity/pix/RCAMiniStereo.jpg

All that's needed

http://www.kozco.com/tech/audacity/pix/MacLineIn.jpg

Circle with two black arrows.

http://www.kozco.com/tech/audacity/pix/ ... lPanel.jpg

Choose Line-In.

Koz

[kozikowski]

The only way you might run into problems with that is if the ADS RDX-150 had internal RIAA equalization for a turntable -- usually required. No Google hit I found says anything about an RIAA "Phono-In" connection, so I'm guessing you're much further ahead with just the straight cable.

If you're using an older non-electronic turntable (what was the model number on that?), you do need to come up with RIAA compensation somewhere. Vinyl music is intentionally distorted to greatly increase fidelity overall, but you have to take the "distortion" out later with a phono-preamplifier -- or software that does the same thing.

Phono Preamplifier
-- Two very nice phono preamps in actual use.
-- Honorable mention to the Hafler HD-101 preamp, no longer made.

http://www.phonopreamps.com/tc750lcpp.html
http://www.artproaudio.com/products.asp ... =13&id=109

Koz

[oldalaskan]

Many thanks Steve and kozikowski. I'm very impressed with the quality and quickness of your responses. I'm using a Musical Fidelity X-LPS phono stage which includes RIAA equalization. So all I need is the right cable to connect between it and my laptop. I was trying to use the ADS RDX-150 because I didn't know what I was doing. But I know a little more now!

[kozikowski]

The stereo Line-In of a Macbook Pro is a world class digitizer.

Koz