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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
lewm
12,994 posts
 
Dear Hiho, I am not sure what you mean. Any well designed tonearm should have no play in the bearings, regardless of the offset angle. Unipivots are uniquely likely to induce a variation in cartridge azimuth during play, because they can potentially rotate around the pivot, and need to be designed so as to avoid or reduce that problem, vis the Graham. But the prime reason for a need to adjust azimuth is the variability among cartridges in the accuracy of the alignment of the motor with the external boundaries of the cartridge body. If that were always perfect, one could just align with a mirror. Possibly I have misunderstood you, and if so I apologize.
hiho
451 posts
 

It has nothing to do with play in the bearing. Just take a look from the top view at the ubiquitous Rega RB-300 and notice the vertical bearings angled at 23 degrees from the armtube that also matches the same offset angle at the cartridge, also 23 degrees. It's a geometric issue. Any pivot tonearm that does not have this angle when changing VTA the azimuth also changes with it. To illustrate my point, just imagine the cartridge is mounted at 90 degrees from the straight armtube and when you change the azimuth, the VTA changes with it. Take a look at bearing arrangement in all pivot arms around you and notice how the bearings are angled approximately 23 in relation to the armtube, including the Triplanar that you have - although the azimuth adjustment of the Triplanar is by rotating the armtube so it would affect the VTA. Again, it's a geometric issue and has nothing to do with bearing quality. I hope this makes sense.

I personally prefer tonearms that provide azimuth adjustment that takes this offset angle relationship into consideration. Only the Graham arms, Basis Vector, Continuum Copperhead & Cobra, Well Tempered Arm, and few others have this feature. Of course any arm with detachable headshell can use something like a Sumiko headshell that's rotatable.

_________
guinness
48 posts
 
Oops. Disregard my Wallyskater comment. Too much Pliney the Elder or the homebrew equivalent yesterday. I did set azimuth by ear though, trust me.

Relax, have Lagunitas Kill Ugly Radio and listen to some Kenny Burrell...
dan_ed
2,451 posts
 
Hiho, I am sorry. I have read your last two post several times and I cannot grasp what it is you are saying about bearing angles and AS and VTA. Can you explain that in simple terms?
lewm
12,994 posts
 
Essentially, I think Hiho is saying that to adjust azimuth without altering VTA, the adjustment must be made downstream from the ~23 degree offset angle that is typically built into the geometry of fixed bearing tonearms. (It's not always 23 degrees; I own two tonearms, the Kenwood L07D tonearm and the Dynavector DV505 where that angle is less than 23 degrees.) If you adjust azimuth by twisting the arm upstream from the bend, then you are also changing VTA. Is that correct, Hiho?

Never having seen any of the tonearms Hiho mentions as exceptions, I don't readily understand how they work, unless the headshell itself twists about its own axis, as in the case of a removable headshell with built-in azimuth adjustment capability. The newer Reed tonearms also avoid this issue by allowing azimuth adjustment right at the headshell, but this adds several grams in terms of effective mass.
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