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you could even add a track, with a nice voice, that explains everything on the disc - then you can never lose the documentation
LOL, I had kind of thought the same thing. 🙂
Don't some of the Stereophile discs have tracks like that?
Don't some of the Stereophile discs have tracks like that?
How about a sweep with audible "markers" every 500hz? It's always driven me crazy when I can no longer hear anything and I don't know what frequency it's at.
A tone where 1 channel is a slightly different frequency than the other so we can hear the beats caused by the freq difference? Or will this not work since the 2 tones are coming out of 2 speakers?
A tone where 1 channel is a slightly different frequency than the other so we can hear the beats caused by the freq difference? Or will this not work since the 2 tones are coming out of 2 speakers?
A 500Hz tone would slam needles against the stop in a meter really hard. You can't do that.
-Chris
-Chris
Guess i wasn't clear. I meant during the sweep, at every 500hz increment, have an audible marker blip so we can know where in the sweep it is. So at 1,5khz, 2.0khz, 3.5khz... etc, just have an audible indication of where in the sweep we are
to make an absolute speed measurement disc.
find a used disc with the hole suitably near the center
take a flat edge and position it radially from the center to the edge,
using a scribe, box knife or other suitable tool, mark a line from the center out,
play and measure for the 1.8sec tick arrival.
DIY forever!
Cheers
Alan
find a used disc with the hole suitably near the center
take a flat edge and position it radially from the center to the edge,
using a scribe, box knife or other suitable tool, mark a line from the center out,
play and measure for the 1.8sec tick arrival.
DIY forever!
Cheers
Alan
That's the raw data filtered, what you would do is take the second figure to get frequency and the third for amplitude and plot it on any scale you want.
The Hilbert transform figured heavily in Dick Heyser's work on speakers, I don't know if there is a specific track that would use it to get new information about the phono setup.
By the way, all the lathe tables I am familiar with are provided with strobe markings on the outer edge and are "always on" to provide a convenient indicator of absolute speed measured against the power grid. At worst, the absolute speed of the cutter should be pretty close.
Cheers
Alan
Cheers
Alan
Cut all the way and average the two .9sec periods to eliminate the centering issue? I'm thinking aloud here.
not a bad idea to average the two, complementary to the rescue.
not sure how much of a difference the error would make, would have to crunch the numbers, which doesn't interest me much.
outer groves best.
Cheers
Alan
not sure how much of a difference the error would make, would have to crunch the numbers, which doesn't interest me much.
outer groves best.
Cheers
Alan
With reference to
Test LP group buy
Attached is the detailed description from the inner sleeve of the MHV (Hungarian Record Company) test record.
Test LP group buy
Attached is the detailed description from the inner sleeve of the MHV (Hungarian Record Company) test record.
Attached are the technical conditions of GZ Vinyl (Home GZ Vinyl), and the table of contents of IEC60098:1987 standard (IEC 60098:1987 | IEC Webstore) for Analogue audio disk records and reproducing equipment. References of test records are in the Appendices. Anyone has got the full text?
The more I read from GZ vinyl, the more they look like the first place to try for mastering.
The notes on the MHZ test LP are very useful, thanks for that.
Here's a question I have. What would make our DIY test LP better or more useful than any other test LP? What can we bring to the disk that isn't already on other test LPs?
I know the answers to some of that - but would like to hear what others think.
The notes on the MHZ test LP are very useful, thanks for that.
Here's a question I have. What would make our DIY test LP better or more useful than any other test LP? What can we bring to the disk that isn't already on other test LPs?
I know the answers to some of that - but would like to hear what others think.
The LPs available new these days are mostly cartridge tracking torture tests, not precision test tools
If we (the people) were to produce a test LP, IMO the main purpose should be to include tests which have so far been omitted, or aren't complete, on current test records. Rather than to recreate existing test records, though one might as well include the standard stuff as well since there's bound to be space.
Viz:
1. Tests which allow easy measurement of f response and harmonic distortion versus level. RIAA encoded and with a sweep rate that allows direct FFT use to yield a theorectical flat line.
Although the industry and most forums focus heavily on f response measurement, there's many reasons in vinyl playback that f response might vary significantly depending upon modulation level. Yes, that's a non-linearity and a big one, and probably unexplored...........
So test tracks which allow f response measurement over a wide range of levels, and over an extended audioband, would allow exploration of probably another big but unexplored part of vinyl playback.
2. Tracks which test trackability and linearity performance for various (constant) groove modulation angles. Essentially so stylus motion tracking the groove is at a constant velocity for much of a cycle, and the cartridge raw output would be a 'square' wave whose ideal amplitude depended upon groove angle. For various groove angles from 5 deg up to about 60.
3. Tracks which test trackability and linear performance for various (constant) groove curvatures. Essentially so that stylus motion is that of constant acceleration in a 'square' wave alternating direction for much of its cycle, and raw cartridge output would be a triangle wave whose slew rate depended upon stylus acceleration. For stylus accelerations between 100 and 1500G, a test of both trackability and linearity. Would also test 'jolt', performance as acceleration switched direction......
4. Proper centering for easy pitch stability measurement using tones at c 3kHz.
5. A standard record whose stylus-groove friction performance could be characterised versus many cartridges. Long silent grooves at beginning and ends of sides.
6. Multiple lock grooves for measurement of wear. 300Hz, 3kHz, 12kHz at realistic peak programme levels.
Probably some more, but that's 2p worth of ideas for a start.
Such things would make the project worthwhile, IMO, and it's only a matter of defining the tracks and synthing them. There's plenty of space..........
LD
Viz:
1. Tests which allow easy measurement of f response and harmonic distortion versus level. RIAA encoded and with a sweep rate that allows direct FFT use to yield a theorectical flat line.
Although the industry and most forums focus heavily on f response measurement, there's many reasons in vinyl playback that f response might vary significantly depending upon modulation level. Yes, that's a non-linearity and a big one, and probably unexplored...........
So test tracks which allow f response measurement over a wide range of levels, and over an extended audioband, would allow exploration of probably another big but unexplored part of vinyl playback.
2. Tracks which test trackability and linearity performance for various (constant) groove modulation angles. Essentially so stylus motion tracking the groove is at a constant velocity for much of a cycle, and the cartridge raw output would be a 'square' wave whose ideal amplitude depended upon groove angle. For various groove angles from 5 deg up to about 60.
3. Tracks which test trackability and linear performance for various (constant) groove curvatures. Essentially so that stylus motion is that of constant acceleration in a 'square' wave alternating direction for much of its cycle, and raw cartridge output would be a triangle wave whose slew rate depended upon stylus acceleration. For stylus accelerations between 100 and 1500G, a test of both trackability and linearity. Would also test 'jolt', performance as acceleration switched direction......
4. Proper centering for easy pitch stability measurement using tones at c 3kHz.
5. A standard record whose stylus-groove friction performance could be characterised versus many cartridges. Long silent grooves at beginning and ends of sides.
6. Multiple lock grooves for measurement of wear. 300Hz, 3kHz, 12kHz at realistic peak programme levels.
Probably some more, but that's 2p worth of ideas for a start.
Such things would make the project worthwhile, IMO, and it's only a matter of defining the tracks and synthing them. There's plenty of space..........
LD
Hi David,
-Chris
There are a lot fewer technicians or technical people to buy these than the average person who would find those tests worthwhile. At a show I was just at, they wanted outrageous amounts of money for these silly "test LPs". Which brings another thought. As test material, we technicians will go through them.
-Chris
Thanks LD, plenty of good ideas.
Should we keep each side to 10-12 minutes to provide for plenty of groove room?
Should we keep each side to 10-12 minutes to provide for plenty of groove room?