One man's opinions/experiences ...
You need to use your ears. These are guidelines, not rules. I've never liked the sound of anything
with flat rolloff, it's always too noisy. The early stuff has very limited high-frequency content so
you can rolloff quite a bit without effecting any recorded sound that made it into the shellac
pressing you are playing. It gets more interesting in the electronic era because there comes a
point -- different times for different record companies, when there actually is important audible
content in the "treble" range and it's loudness is effected by both turnover and rolloff since you
are both moving and bending the curve. Start with the "common wisdom" and then season to taste.
There are many, many listings online of different curves recommended for different record companies
in different eras. I have found the "common wisdom" on RCA, USA Decca, Capitol and Mercury to be my
preferred settings in most cases. The "common wisdom" on pre-electric anything, Columbia, Okeh,
Vocalion and British HMV does not suit my ears, I usually tweak those to sound best to the content
(most content, least noise, to over-simplify it). Almost uniformly, my experience is that the
later-era the 78, the easier it is to pull the content out of the grooves. Early stuff is a
challenge and there's only so much content there.
Also note that not all recordings were made to allegedly "standard" curves, not all recordings sound
good to begin with and not all pressings are uniformly good. So, use the options of variable EQ to
bring out maximum audibility and clarity. Basically, you'll find a pair of settings that sounds
"best" for every record. Sometimes it sounds clearly "best" compared to all other settings
(instruments sound natural, balance of the ensemble sounds right, background noise does not
distract), sometimes it sounds "least bad" because the recording was bad or the pressing is bad,
etc. If your preamp has high-pass and low-pass filters, also experiment with them. You can further
bring out the program content and reduce the background noise sometimes.
I also try to go for the best sound quality at each stage of analog playback so you can then use a
minimal number of stages. If I can get a "best" sound right at the phono preamp, then I don't need
to insert EQ into the signal chain. In the case of 78's, if I can play it back crisp, clear and
relatively quiet, then I don't need to mess with DSP noise reduction or EQ in the computer. Also,
using the combination of turnover and rolloff to both bend and move the curve sometimes produces
much better-sounding results than blind adherence to "common wisdom" with after-the-fact reliance on
heavy-handed EQ to "quiet things down." This method is widely used on low-cost reissues of 78's,
they are usually chopped off somewhere around 10k and "NR'd" to death so all the low-level content
is removed and it's like listening to a low-grade AM broadcast.
Always rely on your own ears and taste rather than machines. Documentation and "common wisdom" is
the place to start, not the place to end.
-- Tom Fine
----- Original Message -----
From: "Jan Myren" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, March 06, 2011 5:33 AM
Subject: [ARSCLIST] Turnover and rolloff curves for correct playback of 78 rpm records!
> I am about to learn to find the general correct turnover and rolloff curves
> for US and European 78 rpm records.
> So far I have learned:
> US 78 rpm records:
> Pre. 1938: turnover 500 (RIIA), rolloff FLAT
> After 1938: turnover 500 (RIIA), rolloff -5
> European 78 rpm records:
> Pre 1938: turnover 300, rolloff FLAT
> After 1938, turnover 300, rolloff -5
> Can anybody share their experiences within this matter, please?
> All the best
> Jan Myren