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Old 29th May 2011, 11:30 PM   #121
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Very valuable, Dimitri! Thanks - I've spent some time trying to sort through various claims from AMR and Graham Slee and others, regarding the equalization curves. Solid info is good to have.
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Old 29th May 2011, 11:35 PM   #122
piano3 is offline piano3  United Kingdom
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Despite a small discrepancy from 10k upwards that sure looks like RIAA to me. I certainly did not expect this kind of hard evidence to appear. One thing, however; this is a very early stereo record and I have a fairly small number of these-they are very thick!-but I seem to remember that these do not have the kind of heavy sound that has been mentioned here. Is it possible that there was a change back to CCIR for some pragmatic reason, perhaps due to characteristics of typical domestic playback equiptment? I hardly think that Thorsten's research can simply be dismissed.
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Old 30th May 2011, 12:59 AM   #123
dimitri is offline dimitri  United States
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From 1959 USSR followed IEC Publication № 98-1 (1959): Recommendations for stereophonic commercial disk records.
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Old 30th May 2011, 02:36 AM   #124
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Dimitry,

Quote:
Originally Posted by dimitri View Post
At least from 1960 RIAA time constants were used in USSR, don't read wikipedia. Here is Melodia measurement record, you can calculate time constants from Table 2 frequency response.
The Test LP whose sleeve you show is issued in 1960?

Ciao T
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Old 30th May 2011, 07:30 AM   #125
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Quote:
Originally Posted by dimitri View Post
At least from 1960 RIAA time constants were used in USSR, don't read wikipedia. Here is Melodia measurement record, you can calculate time constants from Table 2 frequency response.
Thanks dimitri. Cold, hard facts. All my melodiya recordings sound pretty OK with the RIAA. If there was some "dark" sound, it wasn't due to a non standard EQ curve.

By the way, the PH-77 manual implies (see pic i attached previously) that Philips stereo records were not cut using RIAA. I'm currently listening to a early Philips stereo record, very early (dark plum label, AY series which was the 1st stereo series.) It sounds beautifully with RIAA.
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Old 30th May 2011, 07:46 AM   #126
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Quote:
Originally Posted by Telemann View Post
Stereophile gave it a detailed look, with measurements, using the AMR PH-77 adjustment curves:

Abbingdon Music Research PH-77 Phono Equaliser Measurements | Stereophile.com
Ok, from the Stereophile review: PH-77. The secret curves.

Click the image to open in full size.

Red-blue: RIAA
Cyan-Magenta: "Enhanced RIAA" (freq response is relative to RIAA)
Green-Black: "RIAA DMM" (freq response is relative to RIAA)

The "Enhanced RIAA" is within 0.5dB of the RIAA curve at the audible range. Thus it's basically the same thing. Nice.

The "RIAA DMM" is within 3dB of RIAA so basically is a subtle change, a matter of taste.

Click the image to open in full size.
Red-blue: "Decca FFSS (stereo)" (curve relative to RIAA)
Cyan-Magenta: "Columbia"
Green-Black: "CCIR 56"

"Decca FFSS" is within 2dB of RIAA. A slight tonal change. But certainly no difference that could be caused by using significanty different time constants (relative to RIAA)

"Columbia": Same comments as above.

"CCIR 56": This one is different indeed.
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Old 30th May 2011, 09:44 AM   #127
piano3 is offline piano3  United Kingdom
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I spent a month in Moscow in 1990 and heard music for hours every day in the Great Hall of the Moscow Conservatory. If this hall was used extensively for Melodiya recordings, it would possibly explain a lot about the timbre of those recordings.
Whilst on the subject of Melodiya, has anyone any thoughts on equalising of the very earliest mono LP's? They seem to me to reproduce best if they are treated like RCA 78's more or less with not too much bass boost.
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Old 30th May 2011, 10:06 AM   #128
piano3 is offline piano3  United Kingdom
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Also, the extraordinary quality of the lower strings in the USSR orchestras. The amazing double bass sections were, in my opinion, in a different league to those even in the very best western orchestras.
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Old 30th May 2011, 03:10 PM   #129
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When I first read about the AMR PH-77 I thought that we were dealing with a much overlooked area, and mystifying that we weren't seeing more comments about it.

If you go to the product site, you'll find that they are associating correction curves with specific labels:
Abbingdon Music Research - Products - PH - 77 Features

Then I read through the material at hifimuseum.de (which is the same that has been linked to in the thread, from the BBC archivist). And there it became clear that there was no lock-in between labels and curves, as several labels were using the same cutters; and that the introduction of RIAA came much sooner than stated by some.

But an exception must be made for mono-material in the 50s, as that clearly benefits from curves.
I have found no independent confirmation that DGG stayed off-RIAA well into the 60s.

As concerns Melodiya, I've actually performed an experiment. With a number of different issues of Rozhdestvensky's Manfred, with the large RTV orchestra in Moscow. (A brilliant recording).

Soviet issue (reddish cover) - CM 03151-2. Best orchestral sound reproduction through RIAA, without exaggeration.

Eurodisc version (greyish cover with composer in oval) - 87 781 KK - Substantial weight to the woodwinds, but unnaturally so, as if the bass has been boosted.

Version sold in US, manufactured by Capitol Records. Brown/Yellow cover - SR-40267.
Also with weighty bass, but not as pronounced as in the Eurodisc version.

Click the image to open in full size.

Sufficiently different to have me thinking they're not supposed to be this different.
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Old 30th May 2011, 03:49 PM   #130
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Hi,

Quote:
Originally Posted by Telemann View Post
If you go to the product site, you'll find that they are associating correction curves with specific labels:
Abbingdon Music Research - Products - PH - 77 Features
Actually, if you really read the site, you find that we have named the curves after the Labels we have good reason to consider to be the originators, with the single exception of RCA/RIAA, as not having a "RIAA" curve at all would have confused too many and having the same curve called one RIAA and once RCA would have seemed to simply make up numbers... CCIR of course is CCIR and is hence listed as CCIR.

To quote from the FAQ section of the site (Abbingdon Music Research - Information - Frequently Asked Questions):

Quote:
Originally Posted by AMR
"Q: How does one determine which equalisation curve is the correct one for a particular LP?

A: While the notes in the PH-77 User Manual provide informative guidelines, the application of equalisation curves by various different recording labels was in fact, quite inconsistent. Therefore, the final choice really often comes down to listening.
For example:
• A 1960’s Decca USA LP, cut and pressed in the USA from master tapes shipped from the UK, would likely have been equalised to the RIAA standard.
• A 1960’s Decca USA LP, cut in the UK but pressed in the USA, even after the introduction of the RIAA standard, is likely to have been equalised to the the Decca UK in-house standard at that time, which is likely to have been Decca FFSS."
Quote:
Originally Posted by AMR
"Q: How may one tell which equalisation curve to use on a given record?

A: While label, logo shape, country of origin (of the LP, not the sleeve) and year of issue give some indication, they are NOT 100% reliable indicators. However they usually assist one to narrow down to a short list of equalisation curves that may apply.
To determine which equalisation curve is the correct one, the easiest way is to listen and select the equalisation curve (from a short list of likely ones) that produces the most realistic and natural sound."
Also:

Quote:
Originally Posted by AMR
"Q: If the RIAA equalisation curve was standardised in the 1950’s, why are different equalisation curves required?

A: The simple answer is that as not all LP’s have been equalised using the same RIAA equalisation, additional equalisation curves are needed.
At the introduction of the Long Play record (LP) in 1948, most record companies implemented their own particular equalisation curve and continued to experiment with equalisation in order to extract the best performance from the new medium. This led to a baffling array of different and incompatible equalisation curves being applied worldwide.

In the mid-1950’s, most of the record companies agreed to adopt the RCA Orthophonic equalisation curve, the Recording Industry Association of America (RIAA) promulgated this curve as a common standard which became known as the “RIAA equalisation”.

However, as this was essentially an American standard, it had little impact outside of the USA. The RIAA equalisation only became a truly international standard by the mid-to-late 1970’s when European recording labels slowly and finally began to adopt the RIAA equalisation. It was even later when some Asian recording labels joined the bandwagon and adopted the RIAA standard. Right up to the fall of the Berlin Wall in 1989, many Eastern European recording labels (including Russian recording labels) were still, using their own CCIR equalisation.

To further complicate matters, even after officially agreeing to implement the RIAA equalisation curve, many recording labels still continued to use their own, proprietary equalisation, even well into the 1970’s. Columbia is one such prominent example in the USA, Decca/Telefunken/Teldec in Europe is another.

According to Peter Copeland in his excellent “Manual of Analogue Sound Restoration Techniques”:

“I consider the whole subject should be a warning to today’s audio industry; practically everything which could go wrong did go wrong, and it isn’t anybody’s fault. But much worse is everyone’s apparent attempts to hide what happened.”"
There was originally actually a fairly long appendix in the User Manual dealing with the minutiae and quite clearly stating "The EQ depends upon who cut the Lacquer and not on the actual label on the record", however that whole was cut, it may make a reappearance in a more extensive article at some point in the future.

It certainly is a difficult task to give enough information to be useful but no so much as to confuse. It may be AMR erred towards the "do not consfuse the customer side" more than towards "educate the customer", however, not by a huge margin I feel.

Ciao T

Last edited by ThorstenL; 30th May 2011 at 03:57 PM.
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