Azimuth observations and importance


After adjusting azimuth with a Fozgometer loaned to me, the following is what I observed. Individually, these changes were subtle although noticeable. The combined effect however, was significant to the overall presentation.

Imaging improved.

Vocals became more focused, not as big and wide as before.

Instruments more detailed with greater air. Location is more precise.

Tighter bass versus the slightly lingering bass notes previously.

Better top to bottom detail and clarity.

I never realized how important correct azimuth adjustment is and this exercise was quite a learning experience for me. Thinking I was correctly adjusting azimuth by visually setting the headshell as level as possible was a reasonable but flawed attempt.

I have found at least two stylus issues that if present will affect azimuth and sound.

1) A straight cantilever that is twisted left or right changes the attitude of the diamond and its relationship to the groove. By twisted I mean the cantilever has rotated on its own axis. This one is very difficult to see without appropriate magnification.

2) A cantilever that is canted to the left or right a degree or more but is still straight, not bent. It points left or right probably because it was not centered correctly when the cantilever was installed. It also changes the attitude of the diamond.

What is probably basic and common knowledge to everyone here is something I have just been enlightened about after giving it very little thought. I am now convinced that accurate azimuth is a required step in the turntable set up process and I will be giving full attention to this part of the equation.

No more guesswork and eyeballing which I am embarrassed to say was the norm. Doug
128x128dougolsen
I have Fremer's tt set-up DVD but it's useless in this regard. It would be greatly appreciated.

I have not seen MF's video but I believe it comes with a .pdf file that describes the same technique you can read here. Recommended reading it is. At the end of the .pdf are forms from Wally Malewicz for recording your azimuth measurements in a logical way and converting them from volts to dB volts. You might want to print out those forms to use while making adjustments.

As noted earlier, set the volt meter for AC and 5 volts (or less). Measure from the amp's terminals. Remove the speaker wire from the amp when taking measurements with the voltmeter. (You can measure from the speaker terminals, but that means you get to listen to the 1kHz test tone while doing so - I'd rather set azimuth, then listen to music to refine azimuth.) Don't short across the amp's terminals; that is, keep the voltmeter probes separated without metal touching both terminals at the same time.

The needle or digital readout on the voltmeter can jump around a bit, so you'll want to gauge an average - the devices you can purchase such as the Wally azimuth box, and possibly the Fazgometer (?) include a high and low-pass filters to help eliminate this.

Once you get used to playing the tone for each channel, reading the voltmeter and recording your measurements, you'll find it makes sense. Take your time making the azimuth adjustment in v. small increments, followed by a set of measurements to see the result of the adjustment. It may take a couple attempts to gauge that you're adjusting the stylus so as to diminish crosstalk. Once you get to a sweet spot you should hear what the guys are saying to listen for when adjusting by ear. Then you can tweak by listening. Going forward, your ears will know what proper azimuth setup sounds like. Some cartridges are more rewarding of the effort than others. On my Transfiguration cartridge careful attention to azimuth reduced smearing and made a significant improvement in focus. Take it slow and have fun dialing in your rig!
 
Ideally, you would measure the voltage output where the cartridge attaches to the phono stage. This is really unlikely to work well for the unamplified signal direct from a LOMC cartridge, so the next best thing would be to measure the voltage at the output of the phono stage. I personally would not do it at the output of the amplifier, as someone else suggested further up the thread, because there are so many other variables in the chain that could lead to an inaccurate idea of what the cartridge is actually doing. If you have a discrete phono stage, put the red lead into the hole for the center pin of the RCA plug and your black lead on ground (the outer barrel of the female RCA plug or the chassis, at the output of the phono stage). If you have a built-in phono stage in your linestage, then you might have to take off the casing and find the leads that go from the phono section to the linestage section.
Indeed, the most important thing to do when dialing azimuth is to find a particular sound (or a few sounds) in the recording that you can focus on and use for reference. It's not magic science, but it takes patience and focus--just like aligning a cartridge on a fine line--ever got frustrated with that?...

As Doug says, mid to high freq sounds work better than low sounds. Spend some time with a small excerpt of a mono recording (2-3 minutes); listen to it first several times to really hear everything that's going on in that excerpt. Once you've determined the instrument you want to focus on, you can start changing the azimuth setting. Without this preparatory step, you could be spending a long time wondering what to listen to.
There's no short cut here, unfortunately. But that's the fun of it, because the more you hear, the more you enjoy music, with or without azimuth!
Joel
Using a multimeter without the high- and low-pass filters Lew mentioned will probably produce unreliable results. Surface noise from the unmodulated groove wall will be part of the signal. That will look like crosstalk to the meter. Scope users would filter for this of course.

The Wally Analog Shop is just a box containing filters around 1kHz, resistors to simulate a speaker load, speaker terminals as inputs and connections for a multimeter. It takes the output from your amp by plugging your speaker cables into it. That's less than ideal as Lew suggested, since you're measuring crosstalk for the entire amplification chain. OTOH, everybody has speaker cables so it works in every system. Further, a high level signal is easier for a meter to read. If I had to measure at my phono outputs the crosstalk from my best LOMC would be too small to measure or adjust accurately, at least at the resolution of my meter. Measuring at the amp outputs is simple and practical, if slightly "wiggly".

If we're going to fine tune by ear we're going to be adjusting for the crosstalk of the entire system anyway, so...

I guess my thinking was to balance my phono stage (uncommon for most I guess) so that when I do the Ultimate Test Record azimuth test, and won't have to worry that my phono stage is not introducing any error into the test.

I got a little confused; I am using the UTR and I forgot they have left/right channel only for azimuth. I'd like to set it up first with UTR, then listen to music (before/after):

Side 1
General Reference Level
This 1 kHz reference tone will allow you to establish a “base level” for all measurements.
Track 1 1Khz reference tone 7cm/s Mono, in phase (Lateral)
Basic reference for all measurements, adjust meter for maximum convenience (in the studio 0VU).
Adjust preamp channel balance for equal output.
Also used to check the offset angle of the photo cartridge; L&R signals should be exactly in phase as displayed on an oscilloscope.

Azimuth Adjustment
Track 2 1kHz reference level Left channel only
Measure Right channel output.
Track 3 1kHz reference level Right channel only
Measure Left channel output.
The object is to sit the stylus exactly perpendicular in the groove.
Twist cartridge about its radial axis until the measurements from Track 2 and Track 3 are equal or very close to equal for both channels.