Riaa curve

Chosenhandle...There is only one RIAA phono equalization curve. Before this was agreed to different labels did indeed use their own propietary curves.

Axelwahl...You are correct that importance of RIAA frequency accuracy is over rated. The rest of the system, notably speakers, are much less accurate.

One consideration when the the RIAA curve was adopted was that it should be easy to implement. Specs of 0.1 dB are usual and many preamps claim better. Perhaps your spec of 1 dB is a misprint.

Raul....Do you know the spec on the RIAA equalization when the LP is cut, and the frequency response of the cutter, its electronics, and the recorder that made the master, and the microphones?

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.

I don't know how good the cutting equalization is...that's why I asked. Atmasphere might know.

If you can hear a 0.1 (or 0.01) dB boost over the range above or below the RIAA break frequency (1000 Hz I think) who is to say that the boost is bad? It might even compensate for error of the speaker (although 0.1 dB would not be enough to do that).

Raul...Your efforts to achieve perfection are an excellent example of overdesign. Overdesign is a common fault of engineers...I know: I am one.

Remember the saying...

"In every program there comes a time to shoot the engineers and get on with the job".

Atmasphere...What is cut in the vinyl is heard through speakers...the "equation" for what is heard most certainly includes speakers, and a lot of other stuff, and the cutter.

You say that you can find parts that are "CLOSE ENOUGH" to "DO THE JOB". Right on!! That philosophy indicates you don't overdesign.

I am still waiting to hear the frequency response of a typical cutter. and its "pre-emphasis" module.

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.

Rauliruegas...There are more important things for you and Ralph to worry about than 0.01 dB RIAA accuracy. Neither you nor Ralph have suggested a reason why high accuracy RIAA is important when other elements of the system are so much worse with respect to frequency response. As an engineer, I know it's so much fun to see how good you can make your design that it's easy to loose sight of the real performance requirements.

I should have mentioned that I am/was the Aerospace type of engineer and worked on military missile guidance systems since 1961. Back in the day we overdesigned everything. What the hell...we were saving the world from the USSR. Cost was not an issue. It was technically interesting work. (I guess for high end audio cost is not an issue either). But when you think about it putting an H-Bomb 100 feet from the target is not really better than 200 feet.

Phasecorrect
...Don't encourage him!! :-)