Remus wrote:jadis wrote:Remus,
The online oscilloscope program is quite a revelation. And very interesting too. Hope you can guide us through as some of us are very interested to know where to download it and how to use it.
You mentioned that your 'measured crosstalks are 29.82 and 31.40 mV. Good enough for me.'
What would the absolute values be? Like is there such a thing as perfectly 'matched crosstalk'? Like 31.0 and 31.0mv for both channels? And how much is the tolerance to be able to say that 'that is good for me'? Also, can it happen that the measurements are 'good' but the image is off center, assuming nothing else is wrong in the audio chain? Thanks for sharing.
Here it is, Philip:
http://www.zeitnitz.de/Christian/scope_enThere are many other softwares available, but I prefer this one because:
1. it comes with a frequency analyzer, signal generator, etc.
2. it has very low V/div setting- down to 100 microvolts
As mentioned in my post, I only applied the oscilloscope-crosstalk method to check my set-up which has been previously set using the mirror method. Being "good enough for me" means that what I heard is already acceptable to my standard. The magnitude of the crosstalk really depends on the cartridge. Theoritically, it is possible to attain "azimuth perfection" but this depends on the headshell/tonearm mechanism if it allows micro-adjustment of the azimuth, and of course . . . . one's patience.
As for your last question, assuming that the LP is flat, the turntable is properly set up (including the azimuth of the cartridge) and nothing is wrong with the audio chain, then the remaining possible causes of imbalance would be improper speaker placement, room acoustics dissymmetry and impaired hearing of the listener.
Let me rephrase your last question to read:
"What if I have set the azimuth "as perfectly as possible" to the best of my ability, using the mirror method and yet the image is off-centered, what will I do?"
Disregarding the warpage of the LP for the moment, the possible cause of imbalance should start from impaired hearing of the listener down to the cantilever of the cartridge. The logical approach is to check for imbalance starting upstream going downstream. First, with the help of a few sticks of cotton bud, I'll clean my pair of ears
(as they say, the cheapest tweak in audio is ....
). Then I'll check for channel imbalance stage by stage starting with the speaker output. If the imbalance is caused by something that I can not correct or replace, I will not compromise the azimuth setting just to drag the singer to the center of my speakers. I would rather listen to my set-up with the image off-centered; than having the image centered but at the same time I am having anxiety because the stylus might be scraping one of the groove walls of my LP. Pre-owned LPs with noise on one channel only are not uncommon.
As for LP warpage, Methods 2, 3 & 4 (in my previous post) are all based on test lps which might be warped in one direction (either sloping down or up towards the center) to a certain degree. If the LP being played is warped in opposite direction as that of the test LP used for setting the azimuth, then the error would be compounded. Using a flat glass insures that the stylus is aligned to the true vertical, which imho is the best compromise for LP warpage in either direction. Setting up a turntable, like other engineering tasks such as erecting structures or installing machinery, should be based on two fundamental references: the vertical and horizontal. If one is to build a house along a mountain slope, he will erect it along the true vertical; and not perpendicular to the slope.
Tito Mandy,
Dalawang gabi na akong napupuyat. Kasalanan ito ng thread mo. Ang hirap magpost, pupunta na lang kami dyan for exchange of "tastes"
.