The upshot of this SRA business is that the received wisdom of the past was wrong, or at least incomplete. To get theoretically correct SRA, a tonearm could (surprisingly) be raised above parallel to the record surface (sometimes a good deal above parallel), depending on the native SRA of the stylus (which, in Andre’s considerable experience, can range from as low as 86o to as high as 97o—and can also differ substantially from sample to sample of the same cartridge). Of course, your ears must be the final judges in this matter (as in all things audio). My own experience has been that a setting of precisely 92o doesn’t always “sound” best. (Andre agrees and typically aims for an SRA of 91.3o to 92o, the exact setting being adjusted by ear.) Whatever SRA you ultimately decide on, be assured that getting rake angle right (or right for you) has profound effects on every aspect of the presentation—from overall balance to resolution, dynamics, staging, and imaging.
Step six of Andre’s setup is adjusting azimuth. There has been a lot of nonsense written about azimuth—some of it, alas, in the pages of TAS. Trust me: Azimuth matters, and getting it right doesn’t just confer a theoretical advantage; you can readily hear the difference (as you can with SRA).
Unfortunately, getting it right isn’t easy. Once again, you’re going to need a computer and, to do it properly, Dr. Feickert’s wonderful software program, Adjust+.
Adjust+ is actually a suite of programs that permits the precise measurement of all sorts of things, from turntable speed to (as you will see) harmonic distortion. But its foremost function is setting azimuth with high precision.
To use it you have to have a test LP (one comes with the software, although Andre prefers to use The Ultimate Analog Test LP from Analogue Productions). Here’s the drill: Before playing back 1kHz (mono) reference tones for the left and right channel (tracks one, two, and three of TUATLP), you route the signal from the outputs of your phonostage via a (supplied) RCA-to-3.5mm-jack cable to your computer’s mike input. (Andre actually uses a sophisticated outboard 3.5mm-to-USB converter.) Adjust+ then measures (in real time) the mono output of both channels, then the left and right channels of your cartridge, calculating average left-to-right and right-to-left crosstalk in dBs.
Without azimuth adjustment, neither Andre nor I have ever seen a cartridge that measures the same (or even close to the same) crosstalk in both the left and right channels. At the top of the next column, you can see the initial test we ran of the Goldfinger Statement cartridge, adjusted by eye and mirror so that it “looked” as if azimuth were correct.
Crosstalk in this “eye-balled” setup measured -33.4dB L-to-R and -29.2dB R-to-L. Now, folks, that is better than a 4dB difference in crosstalk—from what “looked” like a fairly correct alignment! It should go without saying that imaging and soundstaging would be audibly affected by this setup, and so would timbre.
After considerable trial-and-error (unlike the marvy Kuzma 4Point, the DaVinci Virtu tonearm does not have a geared mechanism to adjust azimuth—you just loosen a set-screw and twist), Andre grew closer and closer to getting optimum crosstalk (equal channel separation and phase angle) from both channels.