Talking about standards.
I have just placed an 'on-line article' at the linearaudio.net website listing many record manufacturers along with the pre-emphasis they used. If you thought RIAA is a standard, check out the list!
The list has been compiled by Katsuyoshi Miguchi, the owner of SoundBox, an Antique Audio shop in Tokyo. It was originally published in Radio Technology magazine in Japan in October 2011. Reproduced here by kind permission of the Author and the Editor of RT magazine. I am indebted to Mr. Nakamura for arranging the permissions and for providing the English language translation.
If you have any additions and/or corrections to this table I would very much like to receive these, and I will update the list as needed. The last update will be noted at the end of the list.
Comments welcome,
jan didden
I have just placed an 'on-line article' at the linearaudio.net website listing many record manufacturers along with the pre-emphasis they used. If you thought RIAA is a standard, check out the list!
The list has been compiled by Katsuyoshi Miguchi, the owner of SoundBox, an Antique Audio shop in Tokyo. It was originally published in Radio Technology magazine in Japan in October 2011. Reproduced here by kind permission of the Author and the Editor of RT magazine. I am indebted to Mr. Nakamura for arranging the permissions and for providing the English language translation.
If you have any additions and/or corrections to this table I would very much like to receive these, and I will update the list as needed. The last update will be noted at the end of the list.
Comments welcome,
jan didden
Hi Pavel,
First, even if this data surveyed pre 1955 LP's only, why should it's validity have changed with time?
Second, this survey claims an end to differing EQ use with RIAA being introduced. This simply not true. Worse is that there seems no record of when everything became RIAA.
Third, any LP pressed in 2012 would use RIAA, the final holdouts on LP EQ converted in the 80's or stopped making LP's altogether.
Ciao T
First, even if this data surveyed pre 1955 LP's only, why should it's validity have changed with time?
Second, this survey claims an end to differing EQ use with RIAA being introduced. This simply not true. Worse is that there seems no record of when everything became RIAA.
Third, any LP pressed in 2012 would use RIAA, the final holdouts on LP EQ converted in the 80's or stopped making LP's altogether.
Ciao T
Pavel,
The way I understand it is that it is an overview of the pre-emphasis these manufacturers actually used. Some entries are bounded by dates/years. others not. Many of these manufacturers have ceased production long time ago so any record that you'd find by them would have the noted breakpoints.
I really don't know when the last one actually switched over to RIAA, or whether there are still holdouts that didn't.
It's something I will try to find out and if I find anything I'll report back
.Of course this is mainly of interest to collectors of vintage records, but for them it should be very valuable data.
I will probably have some more data on this for Columbia later next week.
BTW Did you note those 'interesting' speeds, like 71.29 or 76.59 RPM? There's an interesting story about how they found out that that would be the correct replay speed.
jan
Last edited:
"BTW Did you note those 'interesting' speeds, like 71.29 or 76.59 RPM? There's an interesting story about how they found out that that would be the correct replay speed.
"
I remember reading somewhere about Miles Davis's 'Kind of Blue' - that was not recorded at the standard speed and if you tried to play along to it, you could hear it was slightly off according to the author. Apparently, the CD version has this anomaly corrected.
Before RIAA its easy to envision that there were many different EQ standards that could simply have developed out of engineering preferences. But, I don't know that many people have big collections of pre-RIAA standard LP's that they listen to on a regular basis nowadays and it seems to me that the RIAA is pretty much the standard. This does not alter the fact however that recording engineers will impress their own 'tonal balance' on a recording, so I doubt you can assume they are flat after applying RIAA EQ.
However, the interesting question here is why would they have different speeds when the international standard was 78RPM and 33RPM?
"
I remember reading somewhere about Miles Davis's 'Kind of Blue' - that was not recorded at the standard speed and if you tried to play along to it, you could hear it was slightly off according to the author. Apparently, the CD version has this anomaly corrected.
Before RIAA its easy to envision that there were many different EQ standards that could simply have developed out of engineering preferences. But, I don't know that many people have big collections of pre-RIAA standard LP's that they listen to on a regular basis nowadays and it seems to me that the RIAA is pretty much the standard. This does not alter the fact however that recording engineers will impress their own 'tonal balance' on a recording, so I doubt you can assume they are flat after applying RIAA EQ.
However, the interesting question here is why would they have different speeds when the international standard was 78RPM and 33RPM?
Hi Bonsai,
If you do a correct RIAA (or whatever is used) inverse correction that perfectly mimicks the recording curve, then by definition your result is flat. The fact that the recording engineer sets up his own tonal balance is irrelevant in this context.
You want to do the correction so as to get exactly what the recording engineer has recorded, unless you want to manipulate the sound to your own liking.
I'll try to find more info on your other comments.
jan
Janneman,
Yes, I think we fully agree on this. The point I was trying to make is that the 'tonal balance' that the recording engineer puts down (e.g. boost the treble a bit, or cut bass a bit etc) could be greater than the differences in the various EQ curves. I am not suggesting BTW we change the RIAA - its the standard and for modern (i.e. post RIAA) pressings we should stick with it.
Yes, I think we fully agree on this. The point I was trying to make is that the 'tonal balance' that the recording engineer puts down (e.g. boost the treble a bit, or cut bass a bit etc) could be greater than the differences in the various EQ curves. I am not suggesting BTW we change the RIAA - its the standard and for modern (i.e. post RIAA) pressings we should stick with it.
Still, it is not 'easy' to build a very accurate RIAA. It takes 1% caps and resistors, and a certain amount of 'cut and try' for final adjustment. It also takes really good test equipment, AP is good, but not the only reference.
I use an HP 3563, that can resolve to better than .01 dB to do final selection of the 1% or better (0.5% for Vendetta for example), to get it as close as possible. Just an engineering tweak, because I doubt that anyone could hear even a .2dB difference with real sound reproduction.
I use an HP 3563, that can resolve to better than .01 dB to do final selection of the 1% or better (0.5% for Vendetta for example), to get it as close as possible. Just an engineering tweak, because I doubt that anyone could hear even a .2dB difference with real sound reproduction.
Hey John. OT, but I watched Coppola's "The Conversation" this morning on TV. Nice HD uncut version. That's a great piece of S.F. audio nostalgia. Fun to see all the vintage audio gear, so much of it tape. Really takes me back.
Some impossible things done with audio, but it works for the story. Been 20+ years since I saw it.
Some impossible things done with audio, but it works for the story. Been 20+ years since I saw it.
It depends on how wide a bandwidth is covered, John. I was once testing a speaker where the tweeter level could be adjusted in 0.5dB steps. In single-blind listening, the optimal HF balance fell between two of the settings, one being just a little too hot, the other being just a little too dull. A difference of just 0.25dB covering the tweeter's passband therefore appeared to be significant.
John Atkinson
Editor, Stereophile
You are all treating the RIAA curve as though it exists in isolation. While its a reference when it comes to the sound off the record the decisions are made by engineers listening through speakers (and a lot of stuff in the middle). Sometimes the mastering engineer may only have a tenuous connection to the recording engineer, not both sitting at the mastering desk consulting with each other and the producer. And the decisions are usually made with reference to the experience of the playback, not with reference to an "original sound" if an original sound ever existed.
And some labels may have a "sound" they are trying to achieve which correcting the deviations from RIAA may undo. This can still be true with digital, even though the basic response is essentially perfect so there is less likelihood of the "sound" getting "corrected" out. (That is on a to do list of mine however.)
With tape and vinyl the standards are much more "flexible" (fluid?, adaptable?). The tolerances for both vinyl and tape were in the +/- .5 dB range. Add the two and you can conceivably have as much as a 2 dB fluctuations. Most tape systems are not too precise below 50 Hz for example, even with head bump correction.
Removing variables like RIAA is a good thing and essential for sanity for some of us, but there is no intrinsic magic sonic nirvana to getting it right.
And some labels may have a "sound" they are trying to achieve which correcting the deviations from RIAA may undo. This can still be true with digital, even though the basic response is essentially perfect so there is less likelihood of the "sound" getting "corrected" out. (That is on a to do list of mine however.)
With tape and vinyl the standards are much more "flexible" (fluid?, adaptable?). The tolerances for both vinyl and tape were in the +/- .5 dB range. Add the two and you can conceivably have as much as a 2 dB fluctuations. Most tape systems are not too precise below 50 Hz for example, even with head bump correction.
Removing variables like RIAA is a good thing and essential for sanity for some of us, but there is no intrinsic magic sonic nirvana to getting it right.
John,
In another time and space (in the last millenium) I could buy 1% Tolerance Philips Tinfoil & Polystyrene Capacitors and 0.1% tolerance Holco resistors quite affordably in the shop at my corner in Wood Green London.
Using Lipshitz's math well (we had Excel even then and I have been using for EE calculations since the days of Excel 4 at least) and using multiple capacitors in parallel (which improves tolerance, parallel 4pcs of the same value 1% caps to get a 0.5% cap) it was quite easy to attain a very high accuracy RIAA (and iRiaa to measure) cheaply.
My old Multimeter bought at the same place included a high precision true RMS AC millivolt section, together with the old Philips Tube 'scope that I scored for nearly nothing at a Tonbridge Wells Audio Jumble and a Tone generator it was easy to verify the precision of the RIAA to better than 1% measurement error (better than 0.1dB).
Those where the days.
Ciao T
In another time and space (in the last millenium) I could buy 1% Tolerance Philips Tinfoil & Polystyrene Capacitors and 0.1% tolerance Holco resistors quite affordably in the shop at my corner in Wood Green London.
Using Lipshitz's math well (we had Excel even then and I have been using for EE calculations since the days of Excel 4 at least) and using multiple capacitors in parallel (which improves tolerance, parallel 4pcs of the same value 1% caps to get a 0.5% cap) it was quite easy to attain a very high accuracy RIAA (and iRiaa to measure) cheaply.
My old Multimeter bought at the same place included a high precision true RMS AC millivolt section, together with the old Philips Tube 'scope that I scored for nearly nothing at a Tonbridge Wells Audio Jumble and a Tone generator it was easy to verify the precision of the RIAA to better than 1% measurement error (better than 0.1dB).
Those where the days.
Ciao T
- Status
- Not open for further replies.