RIAA Equalization Standard...

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
The Riaa Standard deviation curve has specific and well defined poles. the 50Hz the 500 Hz and the 2122Hz...poles.

But then theres is some companies that seem to have their own version or interpretation of the Riaa curve..and by reading Thorsten response there seems to quite a bit difference...between these different riaa-curves...

Is there a place or a good resource where i can gather more info on this..???
 
There is essentially only one RIAA curve. The classic paper is by Lipshitz.

There are two minor variations. One 'official' variation adds an LF rolloff from 20Hz, as a rumble/warp filter. An unofficial variation adds an HF boost (I forget the time constant: 7.5us?) to counteract HF cut in the cutting room - some prefer this, others don't.

Any other variation would be, in my opinion, an attempt to put 'musicality' above accuracy. Adjusting RIAA by ear, as some appear to do, is almost guaranteed to get it wrong although the result may sound pleasant. Others get it wrong because the interaction between components in a single network can be counter-intuitive, so a naive calculation leads people astray. I believe one of the motivations for Lipshitz writing his paper was the high proportion of published or commercial designs which were simply wrong, even when the designer wanted to get it right.
 
One other source of confusion is the existence of multiple standards back in the day, with Columbia, Decca, Victor, NAB, FFRR, and a zoo of others all setting individual "standards." Non-standard standards became rare after 1954, but for those with collections of antediluvian disks, attention must be paid to the EQ beyond getting RIAA right.
 
www.hifisonix.com
Joined 2003
Paid Member
There is only ONE RIAA curve and all LP's should confirm to this. I think Thorstens comments were really more around how individual (recording) engineers fiddle with the qualization in terms of boosting bass or treble for example.

The original curve was publisjed in 1964, and there was a second major amendment in 1976 which added the 20Hz breakpoint to counteract the arm resonances and disc warp.
 
Last edited:
Hi,

The Riaa Standard deviation curve has specific and well defined poles. the 50Hz the 500 Hz and the 2122Hz...poles.

But then theres is some companies that seem to have their own version or interpretation of the Riaa curve..and by reading Thorsten response there seems to quite a bit difference...between these different riaa-curves...

Is there a place or a good resource where i can gather more info on this..???

First, I think it is important to be clear what RIAA means.

RIAA = Recording Industry Association of America (more precisely the USA).

Basically this means the guys whose main reason for being in this day and age is to sue it's customers for downloading music.

It was and is a Interest/lobbying group (who gave you the "home taping kills music" campaign and DMCA among others). It is not an organisation who'se decrees have any relevance in law or indeed can enforce adherence to any standards it issues. Even where it's members where concerned it had no way to force them to adhere to any of it's standards (you can be sure the RIAA would not censure or throw out Columbia Records for not using the RIAA EQ).

In the 1950's RCA managed to get the RIAA to adopt it's so-called "New Ortophonic" cutting EQ as standard recommendation to it's members. This meant that other major players at the time (including Columbia) where snubbed and pissed. You can "see" the outcome.

One of the reason for the choice of the RCA Ortophonic curve was that it sat neatly between several of the major competing EQ's (you can see that in measurements of the PH-77 in stereophile). The remaining differences between the different LP EQ's (let's ignore 78's) after RIAA could easily be compensated for in the major part using the even then standard Baxandall tone controls, well at least up to the point when people like John Curl and Mark Levinson hit on the not neccesarily bad idea to remove tone controls).

Now, outside the USA (e.g. most of the world) the RIAA was and still is not even relevant. Local standards existed Europe. Some of this story is well covered in the Sound Restoration e-book originating from the BBC Sound Archive's Peter Copeland.

The whole subject of EQ is really complex (I have in one case the same DG Stereo LP with CCIR EQ, RIAA EQ and Decca EQ - meaning each LP sounds substantially the same if matched with correct EQ but dramatically different if played with RIAA) and there is little material really widely available. You could try the PH-77 pages on AMR's website, I have summarised some of what I found, but it was simplified for release on the website.

Making the EQ of a Phonostage adjustable is quite trivial in principle, doing it for a large numbers of curves and accurately so can be a little challenging (which is probably why FM Acoustics simply used rotary pots with free adjustment). Due to the central location in Europe Germany/Austria/Switzerland had possibly the largest exposure to different EQ's, so adjustability of the EQ curve for LP is not exactly big news there (it is not that common, but definitely heard of).

In principle a simple Baxandall Tone control can also be used, if it is well calibrated, so you know exactly where the +/- 2dB HF boost/cut is and where the LF attenuation settings are.

Of course, in the High End Audio world such a suggestion would be tantamount to Heresy, Witchcraft and Manichaeism (burn the witch, burn...).

Ciao T
 
I always understood that the RIAA curve as we now know it is a kind of artificial construct. I watched a youtuibe vid once of a talk by Steve Hoffman...... - the guy who has remastered a load of classic albums specifically for vinyl. Anyway, the way he tells it, all the record manufacturers got together and decided on the RIAA standard. So goodbye to decca, deutche gramaphone, columbia etc etc etc.

And then the manufacturers went back to their factories and changed not one single thing! They continued to cut the very same as they always had. Apparently this then accounted for why some recordings from certain labels always sounded better than others.

I heard this demonstrated once at an audio show. The demonstrator had an LP from deutsche gramaphone of a violinist called Ricci (spelling might be wrong). Anyway, the guy had earned teh nickname screetchy Ricci.... and right enough with the standard RIAA EQ, the thing was terrible, take your ears off. Then he swtiched to a different curve and the difference was astounding. There was warmth, reall wood tone from the violin, and while all the highs were there, it was so much smoother.

Now I know theres no point in doing a whole lot other than the standard RIAA, but I often wonder how much audible difference there would be in a small change.



Fran
 
Member
Joined 2002
Paid Member
Of course, in the High End Audio world such a suggestion would be tantamount to Heresy, Witchcraft and Manichaeism (burn the witch, burn...).


Who cares? It is the STANDARD that matters. To deviate from the 'standard' without a reset option, gives critics like SY further ammunition to criticize hi end audio design. Let's try to minimize the criticism of our efforts, if possible, don't you agree?

Nice contrast.

Mr. Curl, if hi end audio design (Vinyl records playback section) is to be preserved in isolation, dissociated from it’s “reason to be” for some, what’s the use for them ?

Why you neglect the many music devotees who own classic music records from the past and who have the real need to play back their records in the way it was meant to be?


By the way, SY is known to “eat children for breakfast”.
You are past that age.
Have no fear.

Regards
George
 
John,

Who cares? It is the STANDARD that matters.

Sorry John, but this is is SOOO wrong on so many levels, I don't know where to start.

My position is that we need play back what was actually cut with a reasonably low deviation from the nominal curves, however given the potential differences between different cutting Lathes EQ Cards and all that excessive precision for the Playback EQ is not useful. But having the other curves used over time is.

Standards without sufficiently broad adherence are not standards, they are toilet paper.

To deviate from the 'standard' without a reset option,

As far as I know all the Phono Stages that offer adjustable EQ allow a fixed Reset. In the case of PH-77 which sparked the debate what is present is a standard RIAA Phono (RIAA split between stages) which has a bunch of additional resistors and capacitors that are switched in when needed to modify that curve. So it very easy to go back to plain Jane RIAA, try excotic Miz Enhanced RIAA, brush up on a little Polish with CCIR and so on.

gives critics like SY further ammunition to criticize hi end audio design. Let's try to minimize the criticism of our efforts, if possible, don't you agree?

Sy is not a critic or skeptic, that should be patently obvious to anyone reading him, he is basically plain and simple an SP (Suppressive Person).

So as long as Sy and his Ilk are the critics, I'd like to quote from a song by german singer/songwriter Reinhard May (one of my favourites, sadly unknown outside Germany):

Mit großer Freude sägen
Die einen an meinem Ast,
Die andern sind noch beim Ueberlegen,
Was ihnen an mir nicht paßt,
Doch was immer ich tuen würde,
Ihre Gunst hätte ich schon verpatzt,
Also tu ich, was ein Baum tun würde,
Wenn ein Schwein sich an ihm kratzt.

Und ich bedenk was ein jeder zu sagen hat,
Und schweig fein still,
Und setz mich auf mein achtel Lorbeerblatt
Und mache, was ich will.

Ciao T

PS, a rough translation (appypollylogies for my lack of wit in english, my third language, it is really much better in German):

With great Joy some are sawing
at my branch.
Other are still thinking
what they dislike about me.
but whatever I would do
they would never be pleased.
So I do as a tree would
should a pig rub against it.

And I consider what each has to say,
and say nothing
And seat myself on my eighth of Laurel Leaf
and do as I will

PPS, full lyrics here:

i-songtexte.com | Songtext/Lyric Mein Achtel Lorbeerblatt von Reinhard-Mey

PPPS. John, please remember, a long long time ago, far from the maddening crowd a wise man once said:

"Do what thou wilt, that shall be the whole of the law."
 
Hi,

the way he tells it, all the record manufacturers got together and decided on the RIAA standard. So goodbye to decca, deutche gramaphone, columbia etc etc etc.

And then the manufacturers went back to their factories and changed not one single thing! They continued to cut the very same as they always had.

Nice summary. Also, we must remember that LP's where never made for Audiophiles, they where meant to be played on generic consumer equipment, which in the 1960's would often lack bass and treble.

Play an LP cut a'la Decca or Columbia on such gear and it would sound "better", so the companies actually not only had no incentive to switch, but often an incentive to keep their "house curves" even with the standardised RIAA Playback EQ.

I heard this demonstrated once at an audio show. The demonstrator had an LP from deutsche gramaphone of a violinist called Ricci (spelling might be wrong). Anyway, the guy had earned teh nickname screetchy Ricci.... and right enough with the standard RIAA EQ, the thing was terrible, take your ears off. Then he swtiched to a different curve and the difference was astounding. There was warmth, reall wood tone from the violin, and while all the highs were there, it was so much smoother.

Yes, many Decca (UK) and Deutsche Gramophone (Germany) LP's where cut using the Decca EQ, also Telefunken/Decca aka. Teldec.

US cuttings from either label where usually RIAA, however especially in earlier days often only pressing masters where shipped to the US for pressings, not the master tapes, so a lot of the US Pressings from these labels that where pressed from UK/DE cut masters are Decca. Equally, I have pressings of US recordings issues by Decca UK sub-labels (Vox/Turnabout especially) that are clearly RIAA and appear to have been pressed from US made stampers in the UK.

Now I know theres no point in doing a whole lot other than the standard RIAA, but I often wonder how much audible difference there would be in a small change.

I disagree on the "no point".

If most of your LP's are recent audiophile re-issues and/or post 1980's pressings then "only RIAA" will do.

If you own substantial numbers of 1950's and 1960's Decca (and sublabels), Columbia, Verve, Deutsche Gramaphone, French Harmonia Mundi, Russian Melodija, Czechs Supraphone and East German Eterna/Amiga LP's then the story is different and having Columbia, Decca and CCIR in addition to RIAA is very beneficial.

The difference is often to make a LP considered sonically below average on a good system with RIAA to sound very good and sometimes even stunning using the correct EQ.

Ciao T
 
Hi,

I would appreciate if you could sketch such a circuit here for a humble diyer.

The Baxandall Tone Control:

Passive Baxandall

Note how the actual curves of the REAL Baxandall Tone Control (not the later +/-20dB variations) are very close to the corrections needed when playing a "wrong EQ" LP using a RIAA EQ. Later variations and the modern active controls that are also called Baxandall (but are not) do not work the same way.

Other approaces are to switch between the different EQ Networks and to calculate your EQ here:

http://www.kabusa.com/riaa.htm

Of course, there are small problems, namely that most currently accessible and extant publication of curves other than the standardised RIAA and CCIR/DIN have (some of) the turnover frequencies wrong, because ALL their writers simply copied from an earlier, wrong article, instead of doing some actual research.

In turn several manufacturers also copied these wrong values and implemented them in their Phono-stages, not realising the EQ curves are wrong as they used "authorative" publications as source. For example the commonly supposedly "Decca EQ" actually removes way too much bass.

The most authoritative, but sadly also incomplete Source is Peter Copland's Sound Restoration Manual.

Ciao T
 
Let me explain myself more carefully. The RIAA is a standard that is known and can be reproduced by any serious engineer. It has been the standard for about 50 years. Are your favorite records OLDER than that. If so, how many?
The correction curves are built into the electronics of recording lathes. This has nothing to do with record companies, per se, they have to buy the electronics from Ortofon or Neumann. Someone, somewhere, might make a 'special' but I don't have any examples. Now what about deviation from the RIAA? It is OK, so long as you are able to, and know how to reset to the RIAA. Thorsten's design did not appear to offer that. However, if it is possible to do that, then everything is OK. If not, then you have added a deliberate frequency aberration to the playback response. This is hi fi? If it sounds 'better' then why? Speaker, room? This is the pitfall. When we make electronics for playback, it is supposed to be compatible with the vast majority of listeners, not a specific room.
 
diyAudio Chief Moderator
Joined 2002
Paid Member

Attachments

  • BZFM.jpg
    BZFM.jpg
    451 KB · Views: 904
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.