Riaa curve

Atmasphere...Ok. I guess I just said "frequency response" when I meant fidelity to RIAA equalization across the whole band. I think that was what we were talking about.

When the record is mastered equalization is usually applied so that the result sounds right to the producer, and when the record is played back equalization may be applied by the user so that it sounds right to him (through his speakers an in his room). With all this going on extreme accuracy of the RIAA equalization seems unnecessary to me.

Eldartford,
you mentioned the cutting lathe and applied (inverse) RIAA.

I would like to know about % deviation found with well regarded 'commercial' phono-pres (not boutique audio).

Looking at the few test graph showings in audiophile’s measurements --- "With all this going on, extreme accuracy of the RIAA equalization seems unnecessary to me." --- it seems some more manufacturer sharing this opinion.

We all know that accuracy will be nice to have in deed, but is it THE prime design parameter I seem to hear it is? Aren't there other much more important ones?

In other words: will it render another product much inferior just because it does not go to the ultimate in this RIAA matter?

Again, (yes, my system sux) listening to my 390S CD and then to the same on LP, I can hear NO colouration with a +/- 1% spec. We also know there are units out there with more than 1% deviation (and not too cheap either).

Eldartford, you are right about that process, but the producer of an LP would never have the EQ of the RIAA messed with! Usually the issue is a private studio and producer have made a recording. They want an LP, so they send the tape to someone who can do that. Usually they also send a tape of test tones made on their tape machine, so the LP manufacturer can set his tape playback to match the calibration of the original tape machine. Then he makes the LP.

The producer then gets a test of the LP and listens to it. He may ask for changes in the tape playback calibration (this is something *very* different from EQ, BTW) in order to get the LP to sound more like it did when the recording was made.

If the LP is being pressed in a different country, this process is often broken. That is one reason why it is so important to get an LP that is pressed in the country where the recording was originally made!

It is a tricky process, no doubt, and full of errors, but one thing that no-one ever seems to mess with is the EQ curves. For the most part, there is a very genuine effort to get the LPs to sound like the playback of the master tape.

Atmasphere...Agreed that no one would deliberately screw with the RIAA equalization. My original point was that 0.1 dB is readily obtainable and more than adequite. 0.01 dB is a waste of effort. IMHO.

Eldartford, it might be, but in the world of high end, the difference between HIFI and the ability to sound like real music exists in the nuances. That is why there are Teflon caps, high precision resistors, care in grounding layouts, spec-ing out the gear octaves beyond human hearing, use of high purity wires, balanced operation (in our case anyway), non-ferrous chassis, *tubes* and whatnot.

We are trying to make it sound real. All designers probably have a blind spot, usually a focus on what they think is important :) so you will see a wide variation in designs as a result. It is the mark of a good designer to know what specs are 'negligible' and which ones are really important that *look* negligible. I don't think I am in a position to really judge exactly what that might be, because like everyone else, I have my blind spots too. In the case of EQ, we can spec the EQ components within 0.05% pretty easily, so I don't think hitting 0.01% should be all that much harder.