How Do I Reverse an RIAA Phonograph Curve?

[Craig Maier]

An important question has arisen regarding the RIAA curve and conveting it to the NAB curve (or any other curve) from an RIAA based preamplifier (and not via a flat preamplifier). Using the Diamond Cut Productions VPP (Virtual Phono Preamp), reverse the curve applied to a file created from a non-flat preamp (one having a built-in RIAA Curve), by doing the following:

1. Bring up the Virtual Phono Preamp (VPP) (found under the Filter Menu)

2. Under Preamp Hardware, check the box that says "Standard RIAA Preamp"

3. Under Record Type, check the box that says "Acoustical"

4. Make sure that the "Enable Tone Controls", and the "Rumble Filter" are not checked.

5. Also make sure that the "Mono" checkbox in unchecked.

Apply that filter to your file and it will become flat (with no RIAA EQ).

If you now want to give that file the NAB (or any other common phonographic curve) bring up the VPP again.

1. Under the presets listing, browse to the curve or record label that matches your desired curve or label and click on it.

2. Run the filter

3. Done

Craig

[Craig Maier]

As an aside, the above description is based on the DC8.5 version.

[cubdukat]

Thanks. This came in handy. I transferred an older Deutsche Grammophon recording of Beethoven's "Eroica," and it sounded kinda muddy with the preamp's curve, so I did this and applied the Decca curve, since I'd read somewhere that DG records were done with that curve. It came out much clearer.

[Craig Maier]

Yes, the Virtual Phono Preamplifier is very versatile in that regard. I use it all the time.