SH Spotlight Vinyl collectors: What is the RIAA curve and why do you need it? See SH Post #7*

There is no such thing as a variable RIAA curve, there is only one RIAA curve. Your machine has pre-RIAA EQ curves on it, for playing records cut before the RIAA style curve became standard. People had large record collections in the early 1950s, mainly 78s and they needed to be played back on different curves. Why? I'll tell you!

First, the RIAA curve has been applied during the cutting of a record since only 1955 or so. This just means that the treble is boosted really a lot and the bass is reduced really a lot so the music can fit on the record. The curve is then applied in reverse at home by your phono preamplifier when you play back the record. The bass is restored and the treble is brought way down and with it, the surface noise (in theory).

Before the RIAA curve it was every company for itself. Each record label had a "secret" EQ curve that was applied to cuttings going back to 1925. Each did the same thing, basically. Reducing bass and boosting treble. But not in the same areas of the sonic spectrum. Sometimes each STUDIO that a label used had their own curve (Decca Records had three studios: LA, Chicago, NYC and each had a different curve in the 1930s and 40s, quite silly).

The idea was, each label thought their curve was the best compromise for good sound with the least amount of "scratch" as they called it, but for this industry wide system to work, the Columbia recordings had to be played back on a COLUMBIA phonograph, HMV or RCA-Victor recordings on a HMV or Victor machine, US Decca on a Decca machine, and so on. These machines had the same curve applied in reverse to the electronics and were the best at getting the most out of the (usually) lo fi gear sound of the time.

This of course went all to hell in the early 1950s when McIntosh and other companies with Hi Fidelity systems started to be sold, so these preamplifier designers of the era GUESSED at a curve for each of the labels and put the switching on the machines. A switch for Columbia records, for Decca, for RCA-Victor and on and on. Chaos. The Columbia Curve on a McIntosh didn't really match the Columbia curve on a different brand of preamplifier in the early 1950s. They were just guessing! This prompted the recording curve to be standardized and the RIAA curve was born, all labels agreed to use it for the good of the industry.

But the older records (even the records cut in 1954 and pressed into the 1960s) were not cut with the proper RIAA curve. So, what to do? Use an old preamp with alternative curves on it?

Here is the kicker. None of these alternate curves really sound good. The reason is that once off of the 1955 standard RIAA curve, everything sounds worse because the surface noise is usually increased. a 1935 speaker won't catch it but your modern speakers will.

So, what I do is leave it on RIAA, even for 1955 and older recordings, even 78s. If I want to alter the sound a bit I'll add some parametric EQ, usually a db or 2 around 35oo cycles with a Sontec slope of 6 to match the older curves. But once off of RIAA, forget it. So don't do it, don't even worry about it.

PLEASE NOTE:

The RIAA curve is NOT on the master tapes, it is just applied to the cutting of the lacquer. YOUR home phono preamp reverses the curve and the music sounds normal to you (hopefully). How WELL your home phono stage reproduces the RIAA curve (how exact) is CRUCIAL to good vinyl playback. Don't skimp on your phono stage, folks!

 

You're right but let's not confuse the people! That's a radio transcription curve.

 

Try it and see. It changed the sound a lot. All bad. Leave it on RIAA.

 

A wide slope. A "1" on a GML Parametric is a "6" on a Sontec Parametric. I'm saying add a db or two around 3,500 cycles with a nice width around it. If you have a graphic, make a nice little mountain peak. Don't overdo it or everything will have a midrange horn clang. Just a hint of it.

 

Glad you got something out of it.

 

Neumann electronics or back in the day, Westrex. The curve is usually right on during cutting. It's the reversing it at home that is the tricky part. Sometimes, the old Japan receivers from the 1970s (Pioneer, Marantz, Sony, etc.) had the most accurate reproduction translation of all, better than many 1950s and 60s phono preamps.

However, the trick is to translate the curve correctly and then make it sound like real music. That is the job of the best phono stages. It's up to your ears to find one that works for you within your price range. Once your home system strays too far off of RIAA, you have a "sound" that is built in to every record you play no matter who mastered it. That is to be avoided at all costs!

 

Of course. On every electric record going back to the 1920s. Don't call it pre-emphasis. That's too confusing.