A real Vendetta?

[syn08]

Originally Posted by FrankWW

I'm not sure it does, but earlier, you said

Kunchur's subjects can discriminate a 3mm change in position in the forward back axis position (@5 microsecond) of the transducers at a distance of @4 meters. In another experiment he got about the same results using a low pass filter. This is equivalent of moving the listener off axis. This might get him pretty close to your 1/8".

These were experimental conditions and real life is different but it's good to know what a psychoacoustic baseline might be

Frank,

There are two different issues here.

One is RIAA channel matching. As I said, I am not sure if 0.1dB (mis)matching is audible (I'd say rather not, but hell, what do I know?).

The other one is matching the RIAA characteristic within 0.1dB. While this is easy to measure as well, I'm pretty confident this can not be identified in a blind test. Perhaps someone from the vinyl industry could jump in and tell us what's the vinyl processing RIAA tolerance, from master tape to cutting.

This is an obviously important difference in practice. Assume you have 10 100nF caps of 2% precision. You can be pretty sure you'll find a pair matched to better than 0.5% (in fact you'll end up with several). But if you add the condition to have them with 0.5% precision, unless you are lucky, you may need more than 10 pcs to sort from. At least that's my experience.

But then again, there's technically not much trouble to reach both 0.1 dB target, so why not?

[john curl]

Again, it is not the ABSOLUTE frequency response of the RIAA network that creates the problem. It is the COMPARATIVE frequency response of the RIAA network to the RIAA standard that makes a level playing field for comparison between designs.
Once, long ago, I adopted an RIAA network for the JC-1 from the Levinson LMP-2, that was designed by Dick Burwin (here it comes, the usual name dropping: One of the founders of Analog Devices, and who, in 1966, developed a hybrid op amp with 100V/us slew rate for ADI, using a topology NOW familiar to all of us). I figured that he knew what he was doing, so I used his network. Guess what, it was slightly off, and when measured in 'Audio' magazine, this was noted. When I asked Dick Burwin about it, he said the he liked the sound of that EQ and that was enough for him at the time. I fixed it (mostly) with a simple resistor change, but I learned my lession, to "Trust, but verify".

[syn08]

Originally Posted by john curl

Again, it is not the ABSOLUTE frequency response of the RIAA network that creates the problem. It is the COMPARATIVE frequency response of the RIAA network to the RIAA standard that makes a level playing field for comparison between designs.

I must be dense today, but what do you mean here by "the ABSOLUTE frequency response of the RIAA network"?

[Salas]

I have the experience that the EQ on records is just about, and in most cases textbook flat restoring Riaa anti filter tends to be subjectively bright. Maybe its the MC carts too, the whole chain is based on loose industrial tech strictness anyway. Did you discover such a pattern with your record collections, or mine are mostly a bit off?

[john curl]

I don't know, I haven't had my first cup of coffee, yet. What would you call it?

[syn08]

Originally Posted by john curl

I don't know, I haven't had my first cup of coffee, yet. What would you call it?

Don't know, but as long as the RIAA standard is in an absolute frequency scale, I guess it's the same as the "relative" to RIAA curve.

[syn08]

Originally Posted by Salas

Maybe its the MC carts too, the whole chain is based on loose industrial tech strictness anyway.

That's what I would expect. And that's why I think matching the RIAA standard to 0.1dB is useless. Matching L/R channels to 0.1dB is another kettle of fish, although I am still not convinced it's really required. Other than for avoiding to dine and wine some Stereophile guys, against a good review. It's measurable, so it can potentially be dangerous for the business!

[john curl]

You bet! Do it right, and there is no complaint. Sloppy, shows indifferent engineering.

[h_a]

What about the gross mismatch between channels of the cartridge itself? A lot of cartridge manufacturers guarentee only an error between channels of less than 1.5dB and that's 15 times the value that's claimed to be heared in equalization.

It's a mechanical system with large tolerances, after all.

Have fun, Hannes

[syn08]

Originally Posted by h_a

What about the gross mismatch between channels of the cartridge itself? A lot of cartridge manufacturers guarentee only an error between channels of less than 1.5dB and that's 15 times the value that's claimed to be heared in equalization.

It's a mechanical system with large tolerances, after all.

Add a max. 25-30dB crosstalk and you got the whole picture on the user side.

BTW, the best Koetsu MCs (you don't want to know how much they cost) are specified at 0.5dB between channels.