AnalogMagik Tutorial 3: How to Set Azimuth on Your Cartridge
(For AnalogMagik Version 1 Users)
Azimuth
Azimuth refers to the horizontal balance of the cartridge when viewed from the front. This, in turn, determines at which angle the stylus sits on the record groove.
The theoretical assumption is that when the Cartridge body is perfectly perpendicular to the record groove, the stylus will sit perfectly in the record grooves. Visual methods using tools such as the Acoustical System SMARTStylus (an acrylic block with grid lines) or bubble levels offer an excellent starting point.
All cartridges are made by hand, and therefore, the stylus may not be perfectly perpendicular to the cantilever, the coil assembly, or the cartridge body. This means visual methods can only provide you with an approximation. As soon as the record spins, whether your stylus is sitting at the optimal spot is unknown, so achieving an accurate setup by eyesight will be less accurate.
If azimuth is set incorrectly, the Stylus will not sit perfectly in the record groove, and signals recorded on the Left Channel will leak to the Right Channel (or vice versa); this leakage between Channels is called Crosstalk, and it is expressed as a negative decibel number. The higher the negative number, the lower the crosstalk, and the better the channel separation.
Incorrect azimuth will also lead to degradation in other measurements such as %THD between L and R channel and IMD% (Intermodulation Distortions).
All cartridges have some inherent crosstalk, but there is no universal standard on what is considered acceptable. Based on our observation, the crosstalk number usually range between -20 dB to -30 dB.
The AnalogMagik software and test LP contain two test tracks that allow you to determine the level of crosstalk between two channels. To determine the optimal azimuth, take readings of the two Azimuth tracks on the test LP, and AnalogMagik will compute the Crosstalk number for you.
In version 2 of the software, both L and R channels can be measured at the same time using 1 test track. This greatly improves accuracy while reducing time.
If the Left channel Crosstalk number is > than the Right channel, twist the cartridge slightly (by approx. 0.5 to 1 degree), and repeat the measurement, or vice versa for the other direction. An optimal Azimuth setting is achieved when the difference between the L and R Crosstalk numbers are as small as possible.
For Example, if you start off with -25.5dB on the left and -28.5 dB on the right, you adjust the azimuth and the numbers will change. Keep adjusting and measuring until the Crosstalk numbers are as close together as possible, .to say -27.5 and -27. How close a number can be achieved between L and R channels depends on the inherent quality of the cartridge and is affected by:
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Channel Balance
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zenith angle of the diamond (whether the diamond is mounted perpendicular to the cantilever
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the relative position of the cartridge coil versus the stylus tip and the cantilever
AnalogMagik is just a distortion analyzer, it will show you changes between L and R channels as you perform adjustments. It will not magically give out good numbers beyond the capability of the cartridge itself, nor will it make adjustments for you.
On some cartridges, it is possible to achieve a number that is as close as 0.5 dB between the Left and Right Channels. On others, you can sometimes get as close to within 1-2 dB difference between channels. AnalogMagik will not adjust the cartridge, it will not correct the channel separation specifications because that is a mechanical issue with the cartridge. That is the job of the cartridge manufacturer, not AnalogMagik.
There are several important factors that one may pay attention to when adjusting Azimuth:
1) Never tilt the cartridge beyond 1 to 2 degree.
If you do this, you will damage the suspension of your cartridge.
On a properly built cartridge, the cartridge should not have to be tilted beyond 1 to 1.5 degrees to achieve optimal crosstalk numbers. In most cases, the optimal number falls within 0.5 to 1 degree. Suppose you find yourself having to tilt the cartridge more than 1 to 1.5 degrees to achieve optimal crosstalk. It is very likely that other parameters are set incorrectly, or there are other undiscovered problems, such as channel imbalance.
2) Channel Balance
If you notice the crosstalk between L and R channels is greater than 3 dB, immediately check the Channel Balance of the cartridge.
If the cartridge has one channel that is louder than the other by, say 4 dB, then obviously, 1 side will leak more signals to the other because it is louder. This effect will amplify through the crosstalk reading, and you will not be surprised to see a 10dB difference.
Phono Pre-amp balance compensation will equalize the volume between L and R speakers, but it will not improve the crosstalk reading.
If your cartridge has a channel imbalance, AnalogMagik cannot fix this for you. Contact your manufacturer.
3) Channel Imbalance will cause crosstalk to widen between channels.
If your cartridge has a channel imbalance of 1 dB, then when you measure crosstalk, the best number you see is a -3 dB difference.
If your cartridge has a channel imbalance of 2dB, it will be audible on your speakers, with one channel being louder than the other, and your crosstalk measurement will at least show a 3-4dB difference.
Phono-stage channel imbalance will also cause the same problem.
In these instances, you cannot use Crosstalk to set azimuth, and you are best off resorting to a perfectly horizontally flat azimuth.
AnalogMagik is like a thermometer, it measures temperature, but it cannot cure the fever.
Only the manufacturer can repair a channel imbalance.
3) Landing Behavior
Azimuth can also be affected by "Landing Behavior" which we talked about in the Basic Alignment Tutorial. If your cartridge has uneven pressure exerted by a cantilever landing behavior that is not going straight up and down, chances are you will never achieve a satisfactory Azimuth Crosstalk reading.
4) Azimuth cannot be set independently of VTA and Antiskating.
Due to the offset angle of headshells, as soon as you change VTA, geometry dictates that it will cause the horizontal level to change, ie) As soon as you change VTA, Azimuth needs to be reset.
Azimuth is also highly affected by Anti-skating and VTF (Vertical Tracking Force). If Antiskating is set incorrectly resulting in uneven pressure on the groove walls, this will often (but not always) cause an imbalance to the Crosstalk numbers. Therefore, you should try to optimize Anti-skating as it will affect the Azimuth setting. Changing VTF and VTA may also affect Crosstalk, and you may have to go back and forth between different parameters and find an optimal point, which will result in a good set of numbers between all parameters.
4) Incorrect Zenith Angle on Cartridges, or incorrect coil angle at the end of the cantilever.
Zenith angle refers to the angle in which the diamond is glued onto the cantilever. Sometimes, it is not perfectly straight, it actually happens quite frequently. Or the coil at the end of the cartridge may not be mounted perpendicular to the stylus.
If there is an inherent imbalance with the cartridge or zenith angle errors, the program CANNOT fix that for you. See No. 2 above. It is a cartridge problem. But there are things we can do to compensate.
When you are setting up Azimuth, sometimes you will notice no matter what you do, the crosstalk numbers between L and R will not come together. Usually (but not always), we will also see:
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Crosstalk between L vs R reading remains far apart (say 5-6 dB difference)
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VTA (IMD% above 10%)
This behavior highly indicates an incorrect zenith angle on the stylus diamond tip, and measuring phase angle will NOT solve this problem. You can use a 200-400x Microscope to examine the zenith angle on the stylus (whether the diamond is mounted straight on the cantilever or is it off-axis). Still, the problem is that a visual observation on a microscope is difficult to transpose the degree angle to actual adjustment.
An incorrect zenith angle will result in a wrong alignment geometry even though the cantilever may be aligned correctly to the gridlines of your template. The way to fix this is to change the alignment geometry (you can try going from Baerwald to Uni), which will rotate the cartridge slightly clockwise if you look at it from the top. By trial and error and patience, you will notice that the Crosstalk number will narrow. This is only true if "Channel Balance" is not the cause of the problem.
In airplane terminology, changing the "Roll" would be changing the azimuth. Changing the Pitch would be changing the VTA, and changing the Yaw would be changing the Alignment angle.
To compensate for zenith angle errors, you change the Yaw angle. The difference between Baerwald, Lofgren, or Uni, is a change in the Yaw angle of the cartridge.
For example, I once mounted a cartridge with a crosstalk number of -20 vs -30 dB, 3dB difference between the channel and IMD% of 12%. After adjusting for the zenith angle error by changing the alignment angle, the cross-talk came much closer together, -25 vs -25.7 (0.7 dB between channels), channel imbalance is now less than 0.5 dB, and IMD% lowered to 5%.
With more patience and fine adjustment, the numbers will likely narrow to within 0.5 dB on crosstalk. VTA IMD% will probably come down to 2-3%.
Also, an optimal setup optimizes readings across ALL parameters; it is a balancing act. Do not be preoccupied with 1 bad reading. Sometimes it is caused by equipment/cartridge limitations, not your setup abilities or AnalogMagik.
Again, an accurate analog setup is a balancing act between ALL and not just one parameter. The goal is to obtain optimal numbers in as many parameters as possible, so do not sacrifice one parameter at the expense of all others. This is why an All-In-One tool is so important because no parameter can be optimized on a stand-alone basis.
5) What numbers to look for?
For the Azimuth Crosstalk measurement, you are trying to equalize the numbers between L and R channels. The goal is not to try to achieve an absolute value of the specific target. If your cartridge specification says 36 dB Channel Separation, it does not necessarily mean you will see -36dB on L and -36.5 dB on L. Many cartridges register numbers below 30dB. This is your cartridge's limitation and a deviation from the specification. There is no need to contact the manufacturer.
This test aims to get the number between L and R channels by less than 1 dB, or as close together as possible.
6) Azimuth using other tools.
AnalogMagik is the only tool that allows you to measure both L and R channels in a single test track. This will result in a higher level of accuracy because by measuring the L channel at a different location on the LP vs the R channel, your results will be affected by tracking errors.
Our programming also incorporates algorithms to account for the imperfections of the LP format, including slightly off-centered spindle holes, slight warpness, and the effect of Wow & Flutter. Do not be surprised if you see slightly different results because almost all distortion analyzers do not take these factors into account.
We also do not advocate using Azimuth as the sole reference and stand-alone parameter as the ultimate determinant for setup accuracy. A proper accurate setup takes into account VTA, VTF, Anti-skating, and zenith alignment, rather than just over-emphasizing on Azimuth. You have to go back and forth between all test parameters rather than treating them independently.
You will find that Azimuth's optimal setting will be different when you have optimized Anti-skating, VTA, and VTF, so do not be surprised when you see slightly different results.
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