The “Korf method” for azimuth alignment
- Thread starter tony22
- Start date
I have come to conclude that the best way is to minimize crosstalk level and crosstalk Δlevel [dB].
The absolute level is different from cartridge to cartridge, but it should come close or better than specs.
The reason to optimize for an as low Δlevel as possible is that it is always the worst channel you will hear, and usually cartridges will converge when the crosstalk level is equal in L and R channel.
To optimize phase is dubious because even a perfect phase crosstalk means a 90° difference, and it will not matter if that is 60, 90 or 120° wrong, it will still mess up the opposite channel. But if the level is low enough you will not hear it.
Just to be sure, What phase error are you referring to? The the phase difference from the Main channel to the channel with crosstalk? Or…
Phase error can result from misaligned cartridge coils. Ideally, the coils for both left and right channels should be aligned at a 45-degree angle to the vinyl surface (in the horizontal plane). However, when using the Korf method to adjust azimuth by aligning the stylus perpendicular to the groove (in the horizontal plane), phase errors may occur. This is because the axis of the coils, which ensures optimal channel separation and minimal phase error, doesn’t always align with the axis of the stylus.
Thanks.
I just found a figure that illustrates why/when crosstalk shifts from being In-phase with main signal, to out-of phase.
The figure shows a situation where the Azimuth is at an angle that gives In-phase crosstalk. Imagine the angles tilted more anti-clock wise, ( Azimuth adjustment) then the arrow for the crosstalk will change direction , and therefore the crosstalk channel will become out-of phase.
Optimal Azimuth occurs when cross talk switches from in phase to out of phase or phase curves cross? . At that point the crosstalk should be at minimum and close to equal.
But the misalignment may be both on coil/generator and stylus tip. So phase change and lowest crosstalk may not coincide.
See top figure, I could not place it below here where I wanted it..
The figure is made with AT95E on a test record that have varying groove cut , 40-50 degree for Azimuth check. Using a 400 high pass filter to get a clean azimuth signal 1khz
.
Last edited:
Thanks.
I just found a figure that illustrates why/when crosstalk shifts from being In-phase with main signal, to out-of phase.
The figure shows a situation where the Azimuth is at an angle that gives In-phase crosstalk. Imagine the angles tilted more anti-clock wise, ( Azimuth adjustment) then the arrow for the crosstalk will change direction , and therefore the crosstalk channel will become out-of phase.
Optimal Azimuth occurs when cross talk switches from in phase to out of phase or phase curves cross? . At that point the crosstalk should be at minimum and close to equal.
But the misalignment may be both on coil/generator and stylus tip. So phase change and lowest crosstalk may not coincide.
See top figure, I could not place it below here where I wanted it..
The figure is made with AT95E on a test record that have varying groove cut , 40-50 degree for Azimuth check. Using a 400 high pass filter to get a clean azimuth signal 1khz
.
You seemed like a bit confused by terms here. Forget all those in-phase crosstalk, main channel, in phase to out of phase, phase curve crosstalk or crosstalk channel. There are no such things like those. At least here, with azimuth. I understood where those are coming from, mixing two things;
- coils being in phase in relation to grooves,
- in phase and out of phase signals normally found in music.
The only thing you should concentrate on is aligning coils to enable maximum channel separation. This way you’ll achieve a more faithful reproduction of the grooves, originally as intended. Yes, stylus and coils are interlocked, they can't be separated, tilting cartridge affects both, but aligning azimuth regarding the coils makes more sense to me. And yes, best possible separation between channels may not always coincide with correct azimuth point which enables correct phase but it’s very close.
Again, forget those in phase, out of phase, crosstalk channel etc. They’re confusing, just try to align coils with a test disc you believe is cut with correct azimuth and flat. Try to achieve maximum channel separation on both channels, aim the highest numbers and if they’re equal for both channels it’s perfect, if not, no problem.
Last edited:
This is where I jump in with my usual rant
, by observing that in my own experience owning probably at least a dozen test records, with multiple copies of some, that I can’t find two of then that yield reasonably close results for channel separation. In many cades the differences are significant. It frustrates the you know what out of me.
I have the same experience;This is where I jump in with my usual rant
Levels are wrong*), even between two tracks the relative levels are wrong, zenith is wrong, azimuth is wrong, VMA is unknown.
Even between two issues of the same test-LP there can be substantial differences.
And these records are not intended for listening. They are made with the sole purpose to calibrate our turntables.
Just imagine the tolerances for regular music records.
*) I can't proove that, but somebody is wrong.
Posted on 2 other forums on WBF discussing Analog Magik....just adding here as it is a new discussion and relevant :
AM I and AM II software was tested against an oscilloscope and was shown to be accurate.....i.e readings either good or bad depending on LP were approx the same ......so the software is great......
AM I and AM II software was tested against an oscilloscope and was shown to be accurate.....i.e readings either good or bad depending on LP were approx the same ......so the software is great......
This is interesting!
But just to be clear;
What are the different figures representing?
Are the two first rows crosstalk dB levels?
What does VTA=2.9809 mean?
Last edited:
Thanks Calle_jr
Please check the Analog Magik website to fully understand figures...
These are the readings from the Software V1 or V2 against different albums as a comparison of different readings from different LP's re the setting of azimuth and how much a difference there is depending on LP
Yes the r and L are dB readings
VTA is IMD distortion percentage
That I get.
And for the azimuth I see what you’re doing. A few notes;
- The levels on the different test LPs are not the same, which means the crosstalk waveform will be more or less good looking, signal disturbances will influence, rms calculation will differ etc. I would assume this may impact some +/-1dB or so, so absolute values must be cautiously interpreted.
- Using two decimal points on dB values only makes it more difficult to read, see previous note.
- The main objective is to minimize the crosstalk difference between L and R channel. The spread is really big, it even changes sign.
For the IMD percentages, the tracks on the test LPs are totally different. Some of them are not even IMD tracks, and the track on AM I is not the same as on AM II.
They can’t be compared, and especially not with four decimal points. Not even without decimals.
THD would be more comparable, but again, the levels are not the same between the test LPs.
I don’t see the point in adjusting VTA based on L and R channel readings.
Thanks Calle...the point of the figures is that Azimuth is set depending on which LP you choose for your Azimuth adjustment....thus setting for one LP depending upon its mastering / pressing etc. accuracy you may in fact be miles out...so which record do we choose and trust....the figures are wildly different ......
VTA is a totally different assumption..again based upon the LP [or even track]
Similar threads
