Adjustable RIAA curves necessary?

Jim Hannon -- Sat, 01/24/2009 - 15:43

In response to my CES Report on Phono Stages, Atul Kanagat writes:
Having explored the impact of the assymetric application of EQ on records from Columbia, Blue Note, Verve, DG, Decca etc, I'd like to suggest to TAS that any phono stage that lacks a variety of EQ options should not be considered a serious audiophile product. The distortions created by the assymetric EQ are very significant and frequency dependant; most audiophiles have never really heard what's on the record for 30 to 70% of their record collections without proper EQ.

I responded with:
Hi Atul,
By your definition, very few phono stages would be considered serious audiophile products. My understanding is that in 1954, RIAA became the de facto industry standard. Prior to '54, each record company used its own equalization so there were literally over 100 combinations of boost and rolloff in use.  A phonostage/preamp would have to account for all these combinations. However, the predominant ones were LP, FFRR, AES, and NAB. 
So what happens if one doesn't have the correct bass boost and high frequency attenuation (on playback)? Nonlinear response in the bass and treble, and conceivably more "noise" in the form of hiss and clicks. Has that been your experience?
I don't know when the group of labels using Columbia EQ (CBS-Sony, Atlantic, Verve, Pablo, Reprise, etc.) and Decca EQ (Decca-UK, London, EMI, DG, Angel, L'oiseau-Lyre, etc.) actually adopted the defacto RIAA standard, do you? Presumably, those recordings after that date would all conform to the RIAA spec and not be problematic (at least for EQ reasons).
In any case, the Zanden Audio site has some interesting information about their RIAA, Decca (FFRR), and Columbia EQ options on their phono preamps.  What other phono stages have these, and other, EQ options?
Anybody else want to weigh-in on this? Certainly a de facto standard didn't require compliance, and some companies, like Columbia and Decca may have continued down their own respective EQ paths for some time. Does anybody know how long?

Cemil Gandur -- Sat, 01/24/2009 - 16:29

My info is similar to yours im: the RIAA curve was adopted as a standard in 1954. Having said that, it is likely that some continued using their own curves for a while after that. I do not know for how long either, but there is suggestion that it was adopted by everyone with the advent of the stereo record (circa 1958).
If  this is correct, the benefit of having adjustable curves on phono stages is minimal, unless one has a significant record collection pre-dating the late 50s.
It would be pretty excessive to suggest that any phono stage without adjustable EQ is not worthy of being a serious audiophile product.

John (not verified) -- Mon, 01/26/2009 - 08:30

I don't think enough of us have experience with adjustable RIAA curves to know what we're missing.  I currently have a new table on load that includes a arm with easily adjustable VTA.  I can easily hear these changes on different records (like 200 gram vs 180 gr).
If the RIAA is a similar sort of change, then we're all missing a lil something...

Jim Hannon -- Mon, 01/26/2009 - 22:07

Looking at the difference in the curves between the different EQ standards, I have no doubt that if one listens to an early 1950s Columbia or Decca (UK) without the right EQ, both the treble and the bass will be "off" with either too much or too little boost. A key question is how many of those records do you have in your collection? 

Atul Kanagat (not verified) -- Wed, 01/28/2009 - 12:56

You would think that once the RIAA curve was published, things would have changed. Not so, based on my listening. Recordings on Columbia continued to use the Columbia curve well into the 70's and 80's. Same for DG and a host of others.
The effect is not subtle.
Perhaps TAS should do some research on this and help us figure out if and when the labels that did not join the RIAA protocol moved over to RIAA.
Listen to any Bob Dylan LP from the 70's with both curves and check it out for yourselves.

Jim Hannon -- Wed, 01/28/2009 - 19:40

Hi Atul,
That's a good point and it would be helpful to know when Columbia, DG, Decca (UK), etc. adopted the RIAA protocol. I pulled about 10 stereo DG recordings from the 60s & 70s, and there are no markings that I can find that indicate a different EQ curve was used. At least some of the 50s mono recordings tell you.
It may very well account for both Columbia recordings and DGs, among others, as being perceived as having "too much treble" (bright) in the 70s? When I had tone controls, I would turn down the treble, which is what, the proper EQ curve would do, in part.  However,  I have some re-issue DG "tulip" recordings from that period that sound marvelous without any EQ manipulation (other than the standard RIAA one).
Quite an interesting topic for some research (while some of the producers/engineers of these recordings may still be alive?). I might just have to go back to the Quad preamp with the "tilt" function---remember that?

Cemil Gandur -- Thu, 01/29/2009 - 07:17

I vaguely recall seeing mention of a list somewhere. Doesn't Zanden send one with their phono stages?

Atul Kanagat -- Thu, 01/29/2009 - 09:44

Zanden currently has three EQ curve options, RIAA, Columbia and "Decca". While the RIAA and Columbia curves are published by the label, the Decca curve is an approximation of a bunch of European curves. I would not be surprised if Columbia and DG LPs have never been changed to the RIAA curve; ALL reissues (Classic records, Speakers Cornewr, etc, etc,) use the RIAA curve. The problem seems to apply only to pressings issued by the label itself.
I am more than convinced that most if not all my Columbias (Dylan, Weather Report, Chick Correa, Leonard Cohen, and on and on) sound harsh and overly bright when played using the RIAA curve and wonderfully musical when you switch to the Columbia curve.
Most vinyl loving audiophiles would gladly pay significant bucks to achieve the improvement  involved. The impact on the music is not subtle.
I repeat my somewhat provocative comment, no phono section shopuld be considered "audiophile grade" if it doesn't offer variable EQ curves.

Cemil Gandur -- Fri, 01/30/2009 - 11:32

I'm having issues with my 'table at the moment, so wouldn't trust checking my LPs on that until I get it fixed. My phono stage doesn't have an adjustable curve, but, at the first opportunity, it's worth checking if my Columbias sound harsh and overly bright - something which I haven't noticed before on a less revealing system.
Will report back in March, when my new all singing all dancing table arrives :)

valvesnvinylfan -- Fri, 01/30/2009 - 11:55

I'd have to concur with atulkanagat: I have a large enough collection of non-RIAA EQ recordings (both pre and post "standardization") to warrant adjustable turnover frequencies and, having heard what that feature can do, think the difference is HUGE. HiFi Plus did a couple of articles on this; don't remember which issues they were unfortunately. But I will say that, once I experienced proper turnover firsthand, a whole new world of sound was opened. Now all I can dream of is getting my mitts on a phono stage with adjustable turnovers. There are a few high quality ones on the market that I know of: the Graham Jazz Club and the VAS Citation both being more reasonably priced options than the Zanden. Of course you can always get vintage preamp with this feature as well--looks like they all used to have 'em back in the day.
I'd say every vinyl enthusiast owes it to him or  herself to at least experience the difference firsthand.

Oliver Amnuayphol
Home Theater/Audio Guru
Aperion Audio

Robert Harley -- Mon, 02/02/2009 - 11:19

We're investigating this situation and will publish a definitive article on who used what equalization curves and when.

chrbernhart@blu... -- Thu, 09/15/2011 - 09:42

Hi Robert,
have you already succeeded and published and if so, where?

Atul Kanagat -- Wed, 02/04/2009 - 11:36

Thanks, Robert. That would be a great service to the industry.

Michael Fremer (not verified) -- Tue, 02/24/2009 - 11:29

 My information comes from a Columbia Records engineer. More to come ASAP. I just hate seeing wild conjecture passed around as fact.
Question: "What curve did Columbia use in the RIAA era? Was it their own? On Bob Dylan albums (etc.)?"
So far, with more to come:

    "I really don’t think so. I believe that the RIAA curve was the standard for quite some time.   And I remember seeing “RIAA” on many of the cutting cards of that period."

 " I will ask some of the “older” skool (I started at CBS 1987) and see what they say."

 "But something to think about, many of the “pop” record of that period were cut at outside mastering houses such as Sterling, Masterdisk, Kendun, or the Mastering Lab.  It would be hard for me to believe that these houses were using the Columbia curve." 

  Conjecture should never be passed off as fact....  

Michael Fremer (not verified) -- Tue, 02/24/2009 - 12:12

 Some useful information:
THE RIAA YEARS - In 1952, RCA developed the New Orthophonic curve. Within a year, the Recording Industry Association of America (RIAA) adopted this curve. By 1955, most American labels had adopted the RIAA standard.

The only changes to the curve were definitions adopted in 1974 to set the ultrasonic and infrasonic characteristics of records and playback pre-amps. This change was prompted by the introduction of the CD-4 quadraphonic disc system with its ultrasonic carrier. Note that some European companies did not make the change to RIAA until the 1960s, and some Russian and Asian companies didn't standardize until 1975.

The low and high frequency response limits are fixed at 15 Hz and 22 KHz. The other values are dependent on which recording curve is used. The curve is usually specified by three values, listed in this order:

  1. The bass turnover frequency, in Hz.
    • The values in Hz are: 200, 250, 300, 350, 400, 500, 630, and 800.
  2. The rumble shelf plateau level, in dB above the flat midrange level. This is usually specified as a letter:
    • The values in dB are: X = +12, C = +14, A = +16, B = +18, R = +20
    • N = No rumble shelf used - the bass boost ends at the low-frequency limit.
  3. The treble roll-off, in dB at 10 KHz.
    • Usual values, in dB are: 0, -6, -8, -10, -10.5 -12, -12.7, -13.7, -16, -18.
    • A special value of D indicates a 3 dB/octave slope (instead of 6 dB/ octave) reaching -6 dB at 10 KHz.

The RIAA curve is identified as 500R-13.7, meaning a 500 Hz turnover, a 20 dB high rumble shelf, and a 13.7 dB rolloff at 10 KHz.

Other common curves:

  • 500C-16 = Columbia LP curve
  • 500B-16 = NAB transcription
  • 400N-12 = AES
  • 500C-10.5 = London LP curve
  • 800N-12 = RCA
  • 800N-8 = RCA 78
  • 300N-16 = Columbia 78
  • 250N-6 = American 78
  • 250N-D = Decca FFRR 78

Michael Fremer (not verified) -- Tue, 02/24/2009 - 14:18

 Three genuine, actual Columbia Records veteran mastering engineers on what Columbia Records use for EQ curve (in other words, please, find something better to do with your time than surmise that your  post 1955 Columbias sound bright because RIAA is the wrong EQ curve!)
Sorry about the third response. Don't blame me...
 "To the best of my knowledge the RIAA curve was adopted for LP's as the
            industry standard in 1954 and implemented by 1955.  RIAA is the same
            curve that was used by RCA prior to standardization.  I'm certain
            everybody was on the same page from 1955 onward.  It would make
            absolutely no sense for Columbia to persist in maintaining it's own curve
            because the number of people who would have the equipment with multiple
            curves would be dwindling since no new equipment was being manufactured
            with that capability.

            So, yeah, I seriously doubt there were any new records produced after
            1955 with the Columbia curve.  And certainly not in the 60's much less
            the 70's and 80's.   
    NO! RIAA was the standard from the late 1950's. The RIAA curve  actually started out as the AES curve with slight changes made later which was settled      on as the RIAA curve. During the 78 era there were several curves used. Each label (sort of) had its own curve to try and maximize the fidelity from those old 78's. It is possible that in the eq used on some of those records from the 70's may have "sounded" better when switching to any of those curves. Wait! We are talking here about mono playback curves! Unless someone did something really off the wall and experimented with those old curves, I had no knowledge of anyone, including myself, of having done that.  RIAA curve was and still is the pre-emph/de-emph standard from the late 50's.
            I can absolutely, positively say, there was no "Columbia curve" (in the LP mastering era. The "Columbia curve" was strictly for 78 mastering).
           I suggest whoever came up with this BS should stop smoking crack and get down to
            earth, take a walk in Central Park and smell some fresh air. Is this the case
            of another clueless as...le trying to write the book about the music
            business, while working at the Good Year Tire Center changing oil full time?
            Tell that shmock Columbia was doing the same thing every other studio was
            doing using RIAA curve, period. This has to be the most ridiculous crap I
            ever heard.   

Tom Martin -- Tue, 02/24/2009 - 15:13

Thanks, Michael.

CEO and Editorial Director, Nextscreen LLC

Halcro -- Tue, 02/24/2009 - 22:22

I'd like to thank Michael Fremer for sharing this information and also for demonstrating a 'non-partisan' approach to contributing on this essentially TAS Forum.
Now if 'Mikey' could perhaps involve himself in some of the OTHER topics under Speakers, Amps and Turntables, we'd really have a Forum to rival all others?

Cemil Gandur -- Wed, 02/25/2009 - 05:05

Totally agree. Thanks a lot for the input.

Kool Kat Jazz (not verified) -- Wed, 02/25/2009 - 14:26

Thank you Michael

Jonathan Valin -- Thu, 02/26/2009 - 00:03

FYI, my old colleague Mr. Fremer has just released a new DVD called It's A Vinyl World, After All, full of useful information about LP storage, handling, cleaning, and collecting. I highly recommend it and Michael's Turntable Setup DVD. You can find both at

Atul Kanagat (not verified) -- Sat, 02/28/2009 - 12:12

Thanks for the post, Michael. Glad to see you in these pages.

Ignoring the condescending, if not insulting comments above, I will go back and confirm my listening tests on Columbia and DG recordings from the 60's and the 70's. Maybe I am responding to some magical euphoniuc coloration imposed by an incorrect curve. But I think not.

I refer you to HP'ds article in TAS on the Zanden phono stage; note his reference to recordings from the 60's.

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Atul Kanagat -- Tue, 03/03/2009 - 14:45

I have proceeded with my listening tests on this interesting matter. I continue to believe that there are recordings on DG and Columbia from the 60s and the 70s at least that benefit from application of the Decca and Columbia curves. I am keeping track of my listening and will publish my list soon. I was planning to post these sooner but the virulence of some of the commentary has caused me to double check my own observations and calibrate them via listening tests with other audiophiles in my vicinity. I suppose it is possible that I was being fooled by some euphonic coloration that suits my ears.
Most recently, I threw on a Dylan LP (Columbia) from the early 70's (Greatest Hits, Volume 1). With the RIAA curve he sounds raspy and harsh; I had always assumed that was just part of his voice. With the Columbia curve his voice is so much smoother and more tuneful. I know which one sounds like music.
Analyzing these curves based on listening is tricky. First you do have to use a system that crosses a pretty high resolution threshold to be able to hear and make sense of the music using different curves. I do not know where this threshold is, or whether most listeners ever get that far, making the issue moot for many. Second, you need to have a pretty strong live music reference. In my day job, I serve as VP of R&D at the League of American Orchestras; I attend a lot of concerts and listen to them with my eyes closed to focus on the sound.
Assuming everyone monitoring this thread has a fairly high resolution system (mine is listed below), I would urge you to use your own ears and figure out how you feel based on your own empirical listening. Loud and rude assertions about what's what do not suffice and should have no place in any such dialog.
Getting reliable facts about what happened in the 50s and 60s on this matter remain elusive. Did all record labels, US and foreign, really switch all at once to the RIAA curve in 1954? How did that happen? Was every record cutting system reprogrammed with the new curve? Was this a hard wire fix or a modular or software adjustment? Was it implemented by technicians or by recording engineers, vendors or orchestras themselves? How many of them are still alive today? If everyone did convert instantaneously, why did Teldec formally register a new "Teldec" curve in the late 50's? There is some evidence that DG adopted the Teldec curve, at least for a while. Does the RIAA have any record of conversions or even signatures of executives committing to the new format? How was compliance achieved and monitored, if at all?
My plea is for us audiophiles to be audiophiles. Trust your ears. Frankly, comments attacking a point of view MUST be based on personal conviction through listening before they have any credibility. Remember, our community has successfully challenged highly emphatic assertions in the past based on what we hear; jitter in digital audio is just one recent case in point.
As promised, here are the major parts of my system:
1. Walker Prosceneum Turntable on the Prologue isolation system
2. dCS Scarlatti CD/SACD system
3. Zanden Transport and DAC
4. Zanden phono stage
5. ASR Emitter 2S amplifiers (pair) for 4 channels
6. Nola Grand Reference Towers
7. Nordost Valhalla wire throughout; Thor and Quantum power conditioning blocks
8. Vertex AQ and Walker RF control devices
9. Billy Bags, Grand Prix Audio and Vertex AQ, racks and isolation products
10. Lots of other stuff (Clearaudio Double Matrix, etc)
Best Regards,

discman -- Wed, 03/04/2009 - 10:02

Is it possible that RIAA eq was applied as part of the cutting process, per standards as described above, but that what we hear as bright or bass shy discs is due to EQ elsewhere in the chain? It isn't hard for me to imagine that producers and mastering engineers had to listen through specific speakers and electronics. It isn't hard for me to imagine that current speakers and electronics have a different frequency response and power response that what was in use in 1960 or 1970. Thus there could be not only the random tastes of specific engineers, but also consistent differences from label to label or mastering lab to mastering lab. Those EQ differences would be driven by the large errors of the playback system used for the process, which engineers have to work around.

Cemil Gandur -- Wed, 03/04/2009 - 17:11

 I threw on a Dylan LP (Columbia) from the early 70's (Greatest Hits, Volume 1). With the RIAA curve he sounds raspy and harsh
Sounds about right :)

The Signal Coll... -- Thu, 03/05/2009 - 07:15

Hi Atul,
Out of curiosity, have you compared the CDs to the LPs where possible? I'm curious about the frequency balance. My assumption is that, if a CD is properly remastered from the master tape, then the issue of emphasis leaves the table (so to speak). 

The Signal Collection, LLC
North American Distributors
of Connoisseur-Grade Hi-Fi

Atul Kanagat -- Thu, 03/05/2009 - 09:32

Thanks, Chris. That's a good idea.
May take some work; there's so much going on between vinyl and CD reproduction taht it may be difficult to isolate the effect of EQ. It is definitely worth trying.
In the meanwhile, I am trying to find someone who is willing to research this issue properly, as an investigative journalis might. We deserve to know the facts.

Tektaff (not verified) -- Thu, 03/05/2009 - 13:45

Why the sudden fuss about mismatched phono equalisation? It has been audible all along.
There are bigger differences in the tone of records due to the subjective equalisation and compression applied by the mastering engineer., than there are with the varoius "standards"
The rest of the audio chain is a series of expensive tone controls whereby we match the defficiencies of one product with the other, to hopefully arrive at a fairly neutral sound in the particular space in which we are listening. That's why identical systems sound so different.
Since the 70's, when the use of tone controls on serious hifi was berated, listeners have just accepted listening to the records as they are.
I think there is a justification of using mastering grade equalisation in a listening environment, not only to compensate for listening room/equipment variations, but also for the variations in tonality of the source material.
Equalisation cannot make a rubbish system/room sound great, but it can go a long way to make a good system and the playback medium sound fantastic.
I have a record collection going back some 40 years and it's incredible how bad some of my favourite music sounds. a bit of selective eq here and there is all it takes to make it more listenable.
It's about the music, not the noise it makes!

Atul Kanagat -- Thu, 03/05/2009 - 14:52

Thanks, Tektaff.
I do think that this is probably not relevant to most systems because of many of the points you mention. Like I said above, you do need to have a system that exceeds the resolution threshold for this to make much difference. There is an audible improvement in the sound once you reach a threshold of resolution that mitigates for much of the additional, system induced, distortion.
Try some of your older vinyl with the "right" EQ; you will be surprised.

Cemil Gandur -- Thu, 03/05/2009 - 17:53

Try some of your older vinyl with the "right" EQ; you will be surprised.
Just for the sake of argument (because I do not know what the 'truth' is), couldn't it be that the RIAA curves are correct (as per MF's post) and that your using different curves is just EQing the record differently to sound more pleasant ? That would bring it back to tuning the sound to fit your particular preferences as opposed to reproducing accurately what's on the record. I am not passing any judgement here, and there are tons of lousy sounding records (or CDs) out there, but if accurate reproduction is the aim, then I would very much hesitate in blaming all the ills (including His Bobness' raspy nasal voice) on wrong RIAA curves. EQ away (RIAA or otherwise) if that makes you enjoy the music more, but as far as I concerned, this shouldn't be mixed up with more accurate reproduction with what's in the grooves or the silver disc.

Jonathan Valin -- Fri, 03/06/2009 - 05:25

 I've stayed out of this thread because my experience with phonostages that offer user-selectable RIAA curves has been wildly mixed (and I use the Walker table too). To begin with, the two modern-day preamps I've used that performed this trick--an FM Acoustics and the Zanden--didn't sound at all alike, dwarfing any eq differences. Second, given the "base" sound of each preamp with the standard RIAA curve, I couldn't reliably decide (with either preamp) whether the differences I heard using the Decca curve on Londons and Deccas and the Columbia curve on Columbias were improvements or merely differences. Sometimes I thought LPs sounded better with what was claimed to be the "right" curve for the label; sometimes I didn't. Most of the time, to be honest, I preferred the RIAA curve regardless of label. I think the point that Zeb makes above is well-taken: Applying different EQ is going to change the balance of a record. If it changes the balance in a flattering way, we may tend to think that EQ curve is "right," when, in fact, it may simply be flattering a poor recording (or a series of recordings that were mastered in the same misbegotten way). 
Speaking of which, given the number of truly atrocious-sounding LPs Columbia produced using the RIAA curve (and ten thousand mikes), that third Columbia engineer has nerve calling Atul names! If Columbia "was doing the same thing every other studio was doing," then how come so few of its large-scale classical recordings sound anywhere near as good as the best Mercurys and RCAs (not to mention Deccas, EMIs, Hungarotons, Supraphons, etc.)? Moreover, though I commend Michael for going to the horses' mouths for his info, if you look closely at what they said, each of the Columbia engineers that Fremer cites tells a slightly different story: The first says he "doubts" (which isn't the same as saying he's certain) that Columbia produced any non-RIAA LPs after 1955 (by which time, according to Michael, RIAA had been more or less universally adopted--at least in the States); the second says that RIAA was "standard from the late 1950s"; and the third says he is "absolutely sure that there was no Columbia curve in the LP mastering era." So which is it? Post-1955? From the late 1950s? Or from the dawn of the LP era in the late 40s? Michael leaves the impression that he has debunked gossip. But this is hardly a conclusive conclusion. This is, in fact, three slightly different opinions. But that slight difference makes a difference. If, for instance, I play back one of Columbia's great blue-label mono LPs in the American Music Series from 1950-55, should I use the RIAA curve or the Columbia curve? If I play back one of the gray six-eye label Columbia monos from 1955-62 in the same series, should I use the RIAA curve or the Columbia curve? What about the first stereo LPs in 1958. Is that "late 50s" enough? Should I be playing The Fabulous Johnny Cash or  Milestones or Bernstein's Sacre (of which none other than Stravinsky himself said: "Wow!") with the RIAA curve or the Columbia curve? Nothing these guys say conclusively answers these questions.  (BTW, I don't want to leave the impression that Columbia didn't produce its share of sonic gems--for whatever reason--probably the number and disposition of mikes and the venues they recorded in--Columbia engineers were much more successful with chamber music than with orchestral music. The Stravinsky/Crafts and Walters and a handful of Bernsteins are exceptions.  More significantly, Columbia is far and away the most important label in the world for twentieth-century American classical music. No other label comes close.)
I will soon have the opportunity to hear another phonostage (from a highly reliable manufacturer) with selectable RIAA curves. Once I get it, I will research this whole subject for myself and let you know what I find out. 

The Signal Coll... -- Fri, 03/06/2009 - 13:30

 "so Chris's innuendo--"the issue of emphasis leaves the table"--is sly self-serving propaganda"
What on earth are you talking about? This is about the strangest non sequitur I've read from you.
And "sly"? A completely untoward and inflammatory accusation that has no basis in reality, nor any relevance to what I suggested.
Did you misunderstand me? 
I'll need you to explain in detail how you arrived at this opinion from reading my entry, because it sounds a little [confusing] to me. I suspect you must have misunderstood me, but I can't reasonably respond unless you first explain.

The Signal Collection, LLC
North American Distributors
of Connoisseur-Grade Hi-Fi

Jonathan Valin -- Fri, 03/06/2009 - 13:20

You know what? Rereading your post in the light of day (rather than at 5am in the morning) I think I did misunderstand you. I mistakenly thought you were implying the Walker table was "colored" when in fact you were saying that minus any other explanation the "emphasis" has to be atrributable to the table (or the arm or the cartidge or the combo, I might add). This is what comes of posting when you're tired. I've excised the offending remark. Sorry.

The Signal Coll... -- Fri, 03/06/2009 - 13:25

 Thank you Jonathan ... I was REALLy taken aback and had no idea to what you were referring. Actually - I was called by a friend following the thread while on the road today, who read me your remark and I really couldn't figure out where it came from or why it was made. I know you and I haven't seen eye to eye on a few things over the past couple of years, but this really seemed out of left field.
Again - thank you for addressing my concern and for retracting your comment. 

The Signal Collection, LLC
North American Distributors
of Connoisseur-Grade Hi-Fi

The Signal Coll... -- Fri, 03/06/2009 - 14:20

 " minus any other explanation the "emphasis" has to be atrributable to the table (or the arm or the cartidge or the combo, I might add). "
Actually, what I was saying was that - if there is a question about the possibility that the EQ curve you've chosen to use is "correct" - listening to a CD made from the original master would help someone to understand what the original frequency balance should be like, simply because there is no need for pre-emphasis/de-emphasis in the digital scheme.
Of course that doesn't  necessarily negate the idea that EQ may have been applied more artistically in the remastering process, but it might be a reasonable place to start.

The Signal Collection, LLC
North American Distributors
of Connoisseur-Grade Hi-Fi

Jonathan Valin -- Fri, 03/06/2009 - 14:39

You could also listen to reel-to-reel tapes from this era, if you could find playable ones. But you'd have to make the assumption that non-RIAA'd tapes and CDs and RIAA'd (or Columbia/Decca curve'd) LPs should sound more or less alike, and I'm not sure you can make that assumption. Putting aside the profound sonic differences among these formats, if you've ever thumbed through old issues of High Fidelity from the dawn of the stereo era, you will see how often critics were disappointed with the sonics of the LP versions of material that had previously been released on stereo tape (especially in the first couple years). The problem was that they didn't sound alike (at least on the tables, arms, and cartridges of that day). I would also add that my experience with RCAs reissued on CD (about which I've written fairly extensively) suggests that CDs don't sound like the Golden Age LPs that preceded them; they have their own virtues and vices.

The Signal Coll... -- Fri, 03/06/2009 - 15:24

 I suspected it wasn't a foolproof idea, but thought it might have been somewhat instructive - especially if the LP played @ RIAA sounded extremely off. I had a similar suspicion with an LP of mine not too long ago - 1975's Blood On The Tracks - which I always thought was kind of thin sounding. Turns out ... it's thin sounding. But then again, we don't buy Dylan records for their Van Gelder-like engineering.

The Signal Collection, LLC
North American Distributors
of Connoisseur-Grade Hi-Fi

Atul Kanagat (not verified) -- Sat, 03/07/2009 - 10:37

Thanks Jonathan. I just want to be clear about my own puzzlement with what I am hearing. The differences are as profound as they are subtle when you use the Columbia curve vs the RIAA curve on Columbia recordings from the 70's. It's a little (very little) like pushing the "presence:" button in receivers of yore, I believe that "loudness' or "presence" controls served to boost the midrange and taper of the lo and high extremes. It could artificially boost the image and center fill to make it more palpable, not necessarily true to source.
Listening to these differences calls into play the importance of a neutral reference; in my book that is the Holt/HP articulation: unamplified instruments in an acoustic space (or something similar). This is not easy to do, despite constant listening in orchestra halls around the country. I agree completely that what we might be hearing are distortions that cancel or augment other distortions in the recording chain.
The only way to get to the bottom of this is to find any record of agreements made by various labels and whether there is any record of compliance by labels here and in Europe.
The only other puzzlement worth understanding is the issuance of the Teldec curve in 1958(?) well after the publication of the RIAA standard. Did DG adopt the Teldec curve?
I would urge all those interested in this topic to keep an open mind till we can gather facts and not loud, sometimes rude, hyperbole based on aging memories and deep seated assumptions.

Jonathan Valin -- Fri, 03/13/2009 - 10:59

<<I believe that "loudness' or "presence" controls served to boost the midrange and taper of the lo and high extremes.>>
I don't know about "presence" control, but the "loudness" control did just the opposite of boosting the mids: It boosted the bass and the treble at low volume levels to compensate for the ear's relative insensitivity to soft low frequency and high frequency sounds.

Atul Kanagat -- Fri, 03/13/2009 - 09:41

Continuing the discovery process, take a look at Wikipedia's statement on the adoption of the RIAA curve:
RCA Victor and Columbia were in a "market war" concerning which recorded format was going to win: the Columbia LP versus the RCA Victor 45 rpm disc (released in February 1949). Besides also being a battle of disc size and record speed, there was a technical difference in the recording characteristics. RCA Victor was using "New Orthophonic" whereas Columbia was using the LP curve.
Ultimately the New Orthophonic curve was disclosed in a publication by R. C. Moyer of RCA Victor in 1953. He traced RCA Victor characteristics back to the Western Electric "rubber line" recorder in 1925 up to the early 1950s laying claim to long-held recording practices and reasons for major changes in the intervening years. The RCA Victor New Orthophonic curve was within the tolerances for the NAB/NARTB, Columbia LP, and AES curves. It eventually became the technical predecessor to the RIAA curve and superseded all other curves. By the time of the stereo LP in 1958, the RIAA curve, identical to the RCA Victor New Orthophonic curve, became standard throughout the national and international record markets.
[edit] IEC RIAA curve
An improved version of the curve was proposed to the International Electrotechnical Commission with an extra high-pass filter at 20 Hz (7950 µs). The justification was that DC coupling was becoming more common, which meant that turntable rumble would become a greater problem. However, the proposal did not achieve traction, as manufacturers considered that turntables, arm and cartridge combinations should be of sufficient quality for the problem not to arise.
The intriguing thing is this: if the RIAA curve was chosen because it was within the tolerances for a number of prominent curves of the time, might it be that the standard was adopted by the equipment manufacturers but not necessarily the record labels? I have been interviewing people who may have knowledge of these matters and learned that fidelity in the early days of stereo was very weak with approximations of all kinds being used in the recording - reproduction chain.
Here's a quote from a major audiophile manufacturer who has been deeply involved in designing analog equipment of exceptional merit:
The RIAA curve with its horrid High Frequency boost (75u sec) was also chosen by the Americans for FM broadcasting, as they were besotted with hiss. Distortion problems with this were noted by some in the early 50s (I call this MARKETING not real engineering that we suffer to this day in trying to cut records with bright top end!)
The curve was only specified from 50 Hz to 15 Khz. (Audiophiles seem incorrectly that most cutting systems are very precise.) In fact they are typically not accurate below 50 or above 15 KHz and plus or minus a couple of dB is accepted.

This is interesting because many of the significant differences between curves were at the frequency extremes per the graph in HP's review of the Zanden in TAS.
The search for the truth continues.....

curbfeeler -- Thu, 04/02/2009 - 17:07

I recently contacted Paul McGowan of PS Audio with a suggestion that he produce a version of the GCPH phono stage with plug-in passive modules for other EQ curves. He thinks it's an excellent idea, and is pondering it. The GCPH is a good candidate because of its reported excellence and modest cost, and for the design decision that Paul made to use a passive EQ stage.

curbfeeler -- Fri, 04/03/2009 - 15:40
The sources cited in this manual may prove useful to Hartley and company when researching history and practice of EQ in the recording industry.

Jonathan Valin -- Fri, 04/03/2009 - 21:08

This was, indeed, very interesting.

john195 -- Sat, 09/17/2011 - 07:44

Take a look at this:
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