[isw]

In article ,
Laurence Payne lpayne1NOSPAM@dslDOTpipexDOTcom wrote:

On Thu, 27 Jul 2006 09:04:20 -0700, isw wrote:

It's true that, prior to acceptance of the "RIAA curve" as standard,
each manufacturer had its own preferred EQ, but whatever it was, they
stuck to it. The RIAA curve was a compromise that they all agreed to
because the front panels of preamps were just getting too complicated,
and users were getting too confused because every time they wanted to
play a record, they'd have to get a couple of four or five position
switches set up properly.

How DID the they stick to it?

Even before the RIAA, the various EQ curves weren't arbitrary; each
company had good reasons to justify the EQ they wanted their product to
have, and they had documentation to specify it. So it was merely a
matter of their recording engineers adjusting their gear to achieve it
-- although "just" is way too weak a word here; done properly, vinyl
cutting is a very complex process.

Part of the reason it's so difficult is that the medium (the disk) has
such poor performance at storing audio waveforms. For example, it's not
correct to say that the recording EQ curve is the inverse of the
playback one. It's more accurate to say that the recording curve is
whatever it has to be in order for the resulting disk to exhibit flat
playback response through the specified playback EQ. That way, the
fairly bad response characteristics of the vinyl-plus-cutter can be
partly compensated.

So the short answer is, they measured the performance of their records,
and adjusted the cutting gear until they got what they wanted. The
recommended playback curves were published, usually on the backs of the
record jackets, so listeners could set up their equipment properly.

The RIAA curve was a compromise that all the manufacturers agreed to, to
make it easier for listeners; however, the job of EQ'ing the cutting
gear was just as difficult as ever.

Isaac