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Old 10th October 2017, 08:14 PM   #11
fasterbyelan is offline fasterbyelan  United Kingdom
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Maybe a DIY test LP is a keen idea. Worthy of its own thread, of course. If we can discreetly get other audio forums interested there should be enough demand to make the price reasonable.
My own thoughts exactly, l would be happy to promote the Test LP on the Lenco Heaven Forum as I have been quite active there.

I think most of us have at least 1 test lp so the one we hope to produce need not repeat phase checks, tracking torture tests ect ect. Something very well made is essential (with an accurate spindle hole position!) My own initial thoughts on the tracks would be -

3150 Hz test tone for speed testing and cartridge setting up

Pink and White Noise tracks, the latter to overcome the -10db per decade decrease in energy of the former.

20 - 20Khz Sweep x 2, one with equal energy per octave, one with equal energy per hz.

Silent Track

Those better qualified than me will tell me if the above are possible but my thoughts are for a test lp that can be used for testing cartridge output and frequency response as well as TT and arm performance. Whether there is any benefit to be had from using 45rpm as the LP's speed, again others can comment. (1 side 33 rpm, the second 45 rpm?)
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Old 10th October 2017, 08:42 PM   #12
scott wurcer is online now scott wurcer  United States
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3150 Hz test tone for speed testing and cartridge setting up

Pink and White Noise tracks, the latter to overcome the -10db per decade decrease in energy of the former.

)
All tracks could be generated by computer and verified and exact digital versions could be available as a download. There also should be a pre-discussion of things that were not possible in the past like setting exact crest factors on the noise bands or the possibility of including complex multi-tone signals. Though I suspect the fidelity of anything unusual will disappoint.
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Old 10th October 2017, 10:42 PM   #13
spaceistheplace is offline spaceistheplace
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Maybe a DIY test LP is a keen idea. Worthy of its own thread, of course. If we can discreetly get other audio forums interested there should be enough demand to make the price reasonable.

One nice thing about an open source test LP is that we could publish the original signal files, as well as the mastered files - if that's a help.


Cost can be quite reasonable, even for ~500-1000 units.

When I was doing it RTI was known as the better of the US providers, but they also had a long wait list.

Now that I consider it I find it odd no one has attempted this before.

I think it would be easy to fill up a group buy, especially so if we offered it on Lenco Heaven as well.

Depending on various fanciness I couldn’t see it exceeding $20 or so, which is still less than half some of the modern test records go for.
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Old 10th October 2017, 10:54 PM   #14
Pano is offline Pano  United States
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Though I suspect the fidelity of anything unusual will disappoint.
It would be worth talking to the disc mastering engineers about what they see as stumbling blocks to cutting clean test signals. They should have a good feel for what will work and what won't. Cutting heads aren't perfect.
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Old 10th October 2017, 11:53 PM   #15
davidsrsb is offline davidsrsb  Malaysia
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Half speed mastering would allow accurate sweep up to about 30kHz. Nothing currently available is accurate to 20kHz.
I was at a HiFi show in KL a couple of years ago and the Ellipson test disc sold in hundreds
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Old 11th October 2017, 02:49 PM   #16
anatech is offline anatech  Canada
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L/R channel identification is handy to have in a test situation, then there is how much isolation between channels that can be measured.
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Old 11th October 2017, 03:03 PM   #17
scott wurcer is online now scott wurcer  United States
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There are several members here that have already dealt with small run LP's and I would hope we could find an engineer that would lend a sympathetic ear toward an obsessive requirement for centering of the hole.

As for tracks one that exists on no test LP's is a reference frequency in one channel and a once per rev pulse in the other. I would recommend a single raised cosine pulse that stays inband since there are simple algorithms to place it in time exactly.
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Old 11th October 2017, 03:04 PM   #18
Pano is offline Pano  United States
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Yes Chris, I'd like to have channel ID and crosstalk tests.

I have no idea how much channel separation can be cut into the LP, so we'd want to ask the mastering house about that, and include that info with the test LP.
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Old 11th October 2017, 03:06 PM   #19
Pano is offline Pano  United States
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As for tracks one that exists on no test LP's is a reference frequency in one channel and a once per rev pulse in the other.
For the speed polar plot, right?
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Old 11th October 2017, 03:22 PM   #20
anatech is offline anatech  Canada
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Isn't the standard frequency for speed and W&F test 3 KHz?

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