RIAA, Questions only please

@Ramtubes,
Thanks Roger for the tip, ;yes I usually watch ebay for used test gear from those mfgrs.

best regrds.

What the article leaves me uncertain about, however, given that in modern times a cutting head is to at least a loose approximation a velocity-based transducer (meaning that it converts signal amplitude to groove velocity), is **how** the cutter is caused to cut at constant amplitude at those frequencies.

I think I can answer that. Since the cutter isn't by any means a true constant velocity device, it gets equalized so it is. The CV equalizer is a pretty complex set of time constants; I'd hate to have to work them all out, since the actual cutter response is more like a loudspeaker with some odd peaks in it (complete with a 'nose' in the high frequencies, just like any raw driver response) than anything else. 

Now the slick way to set up the whole thing would be to combine the qualities of both the RIAA curve into the CV equalizer curve so that the output was both at the same time but I suspect in order to preserve hair follicles this wasn't done and probably won't ever :)

Wow! thank you guys, I was just simply provide a link that Roger ( ramtubes) looking for.We should thanks Roger for spending his precious time to open this discussion to unlock the mystery of vinyl disc recording-equalization, answering questions, sharing his expertise and knowledge to us.BTW, Raul (rauliruegas) is the first poster mention the article by Gary A. Galo.

Raul,Roger ,Ralph, Al and all the other fine contributors to this thread and it's previous incarnation.

My compliments to imhififans post and link was not meant to slight any of your fine contributions and I hope that was not your takeaway from it.
I have been intrigued, enthralled and immersed in both threads since inception.
However even if you overlook the differences of opinions and the contradictions of some posts I still found myself struggling to grasp some of the technicalities of said posts at times.

What I meant in my earlier post here was that linked article was just a lot easier to comprehend and digest as a near one stop shop take on the subject.

Nothing more and hope that is understood.

Dear @ramtubes: That's one of the reasons of digital alternative superiority to LPs other that today 32/768 DACs or 4XDSD.

The signal that recording microphones pick up, through that very long " road " on analog/LP, till that LP signal arrives to the system amps is  a real truly TORTURE at each link in the analog system chain.

That means heavy heavy degradations of every kind: distortions, added noise levels everywhere, etc, etc: but we are accustom to the whole LP overall distortions. Such is audio life.

Digital is really simple, even we human beens listen through an ADC at our inner ears.

So, nothing wrong with digital as almost we analog lovers could think.

R.

@imhififan  Thank you very much
About the most complete article I have read so far that at least makes majority of sense and is somewhat easier to understand for the layman imho.

Still living and learning.

Im still learning too. That's the most reasonable article I have read to date. He states things factually, doesn't get into voodo about it. I can imagine the cutter takes some fine tuning and is fussy. I would think the tweeks are not to the RIAA but to other parts of the cutting amplifers.

In a studio tape machine there are 3 adjustments that are made for each reel of tape to get flat response from that reel. Those tones stay on the tape so the next guy in the process has something to reference. While he is adjusting the 10Khz level he is not changing the EQ shape, merely the level and only a few dB.

Dear @uberwaltz: Good that you found out the link P.Ledermann speaks on those threads 10 years ago. As a fact on those threads he made reference to 2-3 of the Galo diagrams. All is in what I posted here and in the other deleted thread.

We only have a shortage on the PL straing gauge italian magazyne review of that first SS model. As a fact before that old hot discussion the link was in his site and after the discussion the decided to deleted.

Anyway, Galo witres the whole " picture " rigth from the begening.

But, as I said before: P.Ledermann was " the man " behind all our posts in these 2 ramtubes threads. I understand that in the past PL made some kind of work at RM. He said it in what I posted here.

Good for him and thak's for your " excersice "/effort/time to found out the Galo papers.

Through those papers I confirm my believes.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Yes, Imhififan has provided us with an outstanding reference on the subject. (Just as he had done, btw, in an unrelated thread not too long ago in which I and Roger had also been participating, which helped bring all parties to agreement). Thanks!

For one thing, the article appears to support statements Roger has made indicating that between approximately 50 Hz and 500 Hz, and above approximately 2122 Hz, records are cut at constant amplitude. ("Approximately" because as I think we all agree the transitions between constant velocity and constant amplitude are gradual, and those frequencies represent "3 db points" as Roger and the article have stated).

What the article leaves me uncertain about, however, given that in modern times a cutting head is to at least a loose approximation a velocity-based transducer (meaning that it converts signal amplitude to groove velocity), is **how** the cutter is caused to cut at constant amplitude at those frequencies.

If I recall correctly Roger had stated toward the end of the deleted thread that that is accomplished by means of an EQ applied to the signal prior to its application to the cutter, the EQ extending over a 60 db range (in addition to the "pre-emphasis"), between 20 Hz and 20 kHz. That would seem to be appropriate if behavior of the cutter corresponds to an idealized model of a velocity-based transducer. However, Ralph responded that cutter characteristics deviate considerably from the theoretical ideal, and with his cutter the required EQ is only about 15 db, and also is not linear over the frequency range. And I had pointed out, among other things, that neither EQ appears to be consistent with application of the approximately 40 db curve that I think we all agree is applied in playback.

Finally, and related to that, although the reference provided by Imhififan refers to the need to reduce groove excursion at low frequencies when a velocity-based cutter is used (specifically between approximately 50 Hz and 500 Hz), how that is accomplished is not made clear as far as I could tell.

So while the article is certainly helpful, and appears to me to be likely to bring us closer to settling these matters, there are still some basic questions that need to be answered before agreement can be reached.

Best regards,
-- Al

Great article imhififan.

Contains an excellent glossary, and what appears to be a complete definition of terms.
For my own benefit as a form of reference, I challenge those in the know, to tell us of any inaccuracies, incorrect data, misleading information, in that article.

*****************
For additional information.
A web page that I was familiar with in the past, from the IASA, these definitions relate to earlier 78’s, and the link contains an interesting table at the bottom. The table shows how varied the EQ’s were between companies, and just how limited in frequency the 78’s were.

A clear case of too many cooks in the kitchen ?

8^0

The control knobs on the preamps that allowed for setup of the different EQ’s must have been interesting.

https://www.iasa-web.org/tc04/mechanical-carriers-replay-equalisation

@imhififan 

Thank you very much
About the most complete article I have read so far that at least makes majority of sense and is somewhat easier to understand for the layman imho.

Still living and learning.

@imhififan  http://hifisonix.com/wordpress/wp-content/uploads/2018/01/Disc-Recording-Equalization-Demystified.pd...

Thanks for sharing this. We need more of you finding articles of quality. As you can see the author found the subject difficult too but made some good points I had not known previously.

Thanks @imhififan. Wasn't the author Gary A. Galo involved with Audio Amateur magazine?

At this point it would interest me to hear from designers (of cartridge transducers and phono electronics) about their opinions on measurements and 'what matters'.

So far frequency response (and corrective eq to achieve it) is the primary topic. This is not the only factor for quality of sound reproduction. It may be of lesser importance than many believe...

My mention (in the last thread) of adjustable eq to factor in cart/cable/preamp interaction was ignored.

Dear @clio09  : Thank's for that because in this same forum several members told me many times something like: " stop to post in this thread " and from many internet audio forums I was banned because the way I'm and because my problems with english language.

Yes, sometimes I have to push people trying to all move on for we all try to go in deep in some audio subject for all we can learn about. People do not like that some one disturb they taking out/off of their confort seat/zone but my intentions always is to help other gentlemans including my self. No one knows every thing about every single audio subject even if some " experts " ( like reviewers . ) think they know everything on every subject.

R.

Dear @ramtubes : Agree with your last sentence:

" it would be nice to see some amplitude contenders come along. "

but what I really want it about is that the dedicated ( no eq. ) preamp will be designed at really top top first rate quality performance levels.

So maybe the overall develpment of those future stain gauge cartridges must need one expert in the cartridge it self and a second gentleman expert in SS electronics and I mean it. The other thing is that that nex generation of strain gauge cartridges NEEDS universal preamps not dedicated ones. ! ! ! ! ? Seems like a good dream.

Of course that gentlemans as J.Carr or any other today top LOMC cartridges could not be happy about but maybe some of them could make/take the flag for that overall strain gauge next generation cartridges.

It’s obvious and this will be the fourth time in your both threads that I say:

with no cartridge signal heavy degradation by the inverse RIAA eq. in phono stages along no needs of additional gain stages signal degradation what we can listen will makes that LP stays in the market for many many years now because that will be a serious very serious challenge against the best digital technology and obviously we MUSIC lovers will take all those strain gauge new generation of cartridges that will makes a paramount differences for the better as never before in the LP/analog history.

R.

RM, btw the P.Ledermann link disappeared from his site and from internet. Unfortunate.

@johnss  with all the discussion on the RIAA curve, would suggest real vinyl philes consider the following; test your LP playback set up and see if the playback response is flat according to the RIAA spec

theres more to this 

.

Thanks for the write up. Its nice to see this level of interest.

Most digital multimeters fall off starting at a few KHZ and at 20 KHz are down as much s 40dB. Get an old HP AC Voltmeter and check it against an oscillator. The meter should not deviate over the audio range.

Used HP, Tektronix, Heathkit. eico and other test equipment are less than 10 cents on the dollar. An oscillator and meters come first Then you can just watch the music and see how much power you are using, your headroom, noise, lots of things.

@rauliruegas  Please also refer to the graph near the top of Mr. Galo’s excellent article called Figure 1;

http://www.smartdev.com/RIAA.html

It refers to this graph as the “typical” RIAA response; in reality, it is far from the “ideal” response that one gets from the theoretical filters due to interaction of those filters. This, not the “ideal”, is what we have all been listening to for years with magnetic cartridges! Superimpose a 6dB/octave curve (Strain Gauge) and you will find that it deviates less than plus or minus one dB.

Unfortunately this link took me somewhere else. Can you check it please?

I thought this part of your quote best and shows that he knows there is a region that needs to fall at 6 dB/octave to get RIAA response. The problem remains on how to get it back to flat from 2200 Hz up. 

Peter Knows.

Your last post makes no sense and is useless and does not makes any real contribution to this thread.

Perhaps not from your point of view, but you did ask what the purpose of the OP’s thread was (both of them) and I posted what I recall to be one of the purposes of the now deleted thread.

Sorry it all got lost on you and your feathers were ruffled.

BTW - care to translate this:

I don’t get yet in which way your threads can help any one of us to listen LPs. ! ! ? ? ? ? ? ? ?

I may have misinterpreted what the purpose or the target was when I previously responded, and yes I read your entire post. You are one of the few people on here whose posts I always read.

@rauliruegas  @ramtubes : What is the purpose or your target on both OP's threads?

I'm asking because today 99.90% of all cartridges we audiophiles own are magnetic ones and the 99.95% of all the phono stages we own or are manufactured comes with the inverse RIAA eq. curve for magnetic/velocity cartridges.

I don't get yet in which way your threads can help any one of us to listen LPs. ! ! ? ? ? ? ? ? ?

What's all about?

This is about understanding. I find understanding something increases my enjoyment of it . Why not be educated? DId I say I was going to help anyone listen to LPs?

Yes we live in a velocity cartridge world except for the few who are still tackling the ampitude world. Neither is better than the other technically however it would be nice to see some amplitude contenders come along. 

@cto517 On a thread like this I am looking to learn. FWIW - I find the available online documentation for RIAA inconsistent, confusing, misleading, incorrect data .. no wonder, imo, it is difficult to grasp when we have experts like yourself contradicting words and terms we have read online..... trying to fill in the blanks.  A definition of terms for important Words would help to fill in some blanks.  Like for example - Constant Velocity, Constant Amplitude

Thanks for your suggestion. You are correct there are many terms being used incorrectly, Here is a list of proper terms. It is most important to use the correct terms and language.

Constant Amplitude is what a wave generator puts out, ususlly as a sine wave. The part that is constant and most important is that it does this at  constant voltage (+/-  by 0.5 db, or better). In Physics it means to move the same distance over all frequencies. If we recorded a record with constant amplitude the wiggle width of the grove would be constant. 

Constant velocity is a bit more difficult. We tend to drive at constant velocity (speed) on the freeway. However there are few things in audio that are constant velocity.

Velocity cartridge produces a voltage proportional to its cantilever speed (velocity). Therefore to produce the the same voltage it has to go much farther in the same time. Therefore the bass grove space get wider.

Amplitude cartridge produces voltage proportional to its cantilever offset or distance without regard to velocity.

Thats a start. Can you name a few more you would like to have defined?

Dear @clio09  : I posted that very long post with all wider explanations from P.Ledermann him self 10 years ago and at the end of that post I said:

""" We have to read the whole history....""" and you did not when that post was " delivered " to you.

Here is again what Ledermann posted 10 years ago and that's is in my post:


"""  Noise?? In fact, the RIAA EQ inherently reduces high frequency noise and distortion in "normal" preamp circuitry; making RIAA a Dolby of sorts. The absolute requirement for a fairly flat (EQ or not) preamp for the Strain gauge was a bit more problematic 35 years ago, as we had to create low noise circuitry for this "flat" preamp to avoid excessive noise compared with a standard RIAA preamp! Creating a circuit in this day and age with "ultra low noise and immeasurable distortion" is a joy, and very do-able. I would rather listen to this one gain stage and an ultra fast cartridge than anything else """


But you read it but not really read it. ! ! !  ? ? ? ? ? 

Your last post makes no sense and is useless and does not makes any real contribution to this thread. I think you agree with this last statement.

R.

@ramtubes : What is the purpose or your target on both OP's threads?

I think he makes it very clear. Now whether I understand or agree with all the technical aspects is another matter.

I don't get yet in which way your threads can help any one of us to listen LPs. ! ! ? ? ? ? ? ? ?

So reduction in noise won't enhance your listening experience with LPs. That was certainly one of the points of the other thread Roger started (how does RIAA reduce noise...), and coming from someone who wants to enjoy the music and not distortion I would think that is important.

Now whether you understood or agree with his points is another matter.

@ramtubes : What is the purpose or your target on both OP's threads?

I'm asking because today 99.90% of all cartridges we audiophiles own are magnetic ones and the 99.95% of all the phono stages we own or are manufactured comes with the inverse RIAA eq. curve for magnetic/velocity cartridges.

I don't get yet in which way your threads can help any one of us to listen LPs. ! ! ? ? ? ? ? ? ? 

What's all about?

R.

Dear @clio09  :  I don't post that " he said " but that he " thinks " discovered the black thread.

Now, here is the overall discussion/explanations that happened in Agon 10 years ago where Ralph and me were in those threads.
It's a very long dialogue but put true ligth in that " unsolved " ramtubes OPs:

with this ( mine ) post started the whole followed discussions/explanations:

""" 

I own/owned and heard all the cartridges named here including your beloved SG and my experiences about were a little different from yours.

First I have to tell that as important is the matching in tonearm/MC-MM cartridge as important is the Phonolinepreamp ( maybe more critical that what we think ) where the cartridge signal must pass through.

I don't know which were/are the Phono stages-line ones that you use to heard your MC cartridges but I can see due to your comments about that no one made/make the right " honors " to those MC cartridges.

I can see too that you speak about tracking and refer to MC and MM cartridges as well the SG but I don't read anything about your MM cartridges that you own or owned. In reference to tracking I'm with some of the best MM cartridges ...

I heard the SG ( I have to say that with oly 30 hours on use. ) in a very very nice top quality home audio system and my first impression was: WOW!!! but after hearing for some time and after comeback from the initial and nice " surprise " I just don't like what I'm hearing specially on the high frequencies and a little in the un-natural tonal balance of its performance, I'm a little sensitive on both frequency extremes and after a time my ears were " tired " of that SG sound ( maybe because that SG was almost new . ) that was not analog like or music live one it was more like a digital source: a good one digital source ( DVDA ).

Fortunately ( for me ) I asking to change to a normal MC cartridge ( in this case was the Lyra Olympos-Essential phonlinpreamp. ) and even than the Olympos was not perfectly matched to that Phonolinepreamp and that I don't know for sure if the Schroder tonearm was the best tonearm match for it suddenly the " lights " goes ON again: overall no contest.
Next day after heard the Olympos switched very brief to the SG and IMHO was a truly deception.

I always said that the RIAA eq deviation makes a great differences in a MC or MM quality performance and only when you hear cartridges in a phono stage with a RIAA eq deviation lower than 0.1db can you understand how important is that subject.

You have to take in count here that the RIAA eq. is a curve where any frequency deviation build colorations on almost three music octaves and this is IMHO what you was hearing in your MC cartridges through your past phono stages: high RIAA eq deviations, not the cartridge design.

IMHO the SG performance in its today status it can't even the very best MC/MM cartridges when these cartridges are in the right tonearm and with the right Phonolinepreamp, this means in even condition/circumstance than the SG matching set-up.

The SG sounds different? absolutely but IMHO and with all my respect to you and the designer: not better. """



10 years ago I listened the PL first version along its dedicated preamp.


next I posted:


"""  Dear friends: Now I can understand, between other things, why the SG sound quality performance is different, please read the page 13 on this Italian review where you can see that the SG frequency response does not mimic the RIAA eq., there are frequency deviations that " build " those differences that I heard.

We have to remember that what is in the recording follow the RIAA eq. standard and on playback and to be near to the recording the cartridge/phono stage: MC/MM or SG must mimic it, this is not happening with the SG and that's why the differences that we can hear. """


here the first P.Ledermann answer:


"" 
While I apprecaite all the comments, and empathize with those who love audio and the attempt to explain what they hear though technical terms, there comes a point where it makes sense for the designer to make a stab at clearing the air. I will address two issues: 1) Relevant factual information that might shed some light, and 2) Technical information intended to both enlighten and confound, strictky due to the real world complexity of why things sound as they do.

1) The Italian article did a very good job of explaining to a general audience the difference between "velocity" devices and "displacement" devices, and how RIAA is handled. That was, in part, their objective - it was to inform.

2) Comments that attempt to quantize one's experience by referring to amplitude pertubations are equivalent to four blind men each describing what an elephant is by touching varied parts - and invariably giving an incomplete view of the animal. Sound is complex - yes - if there is a terrible amplitude anomoly, it makes for bad or unlistenable products. But audio has a long litany of products that are quite wonderful that are not "flat".

The human ear lives in the time domain - if this fact is not understood by enthusiasts approaching the field, it is part of audio 101. There are those who insist on .1dB flatness without undertanding that a full sytem tuned and maximized for flatness often introduces phase or time error that are a cure worse than the disease. The small pertubation bumps one sees on a speaker reponse are just that - phase interractions. They give, in part, the tonal flavor of a product.

Although we have made some recent changes on our preamp design to realize a very small change in amplitude and phase flatness, the original product was well received by most listeners and owners. If the frequency response were very bad, that would not have been the case.

What is important to gather (which is hard to do)is what time errors occur in any product, how many, where do they exists in the freq domain, how far do they spread, and how serious are they? This describes only one part of the problem when trying to use technical terms to exlain what we hear. We listen to speakers that are far from flat, in environments that are far from perfect, and often get very good results. Why is that??

The answer in part is that. What is the rise time of the product (how fast is it). Does it ring (resonate) if it is a transducer. How much time shift is there, and how much. THEN, what is the overall response.

If a products design criteria are in accord with certain critical parameters that physics say are good things, it may in fact work well. From then on, your ears are the judge. But do get the laws straight. Amplitude flatness can easily be done at the sacrifice of other MORE IMPORTANT parameters. ""


he followed in a second post:


""  Most manufacturers who have been in this industry for any length of time, as I have for 38 years, know the rules: never say anything publicly, or privately, about anyone else’s product. It is called etiquette, and not shooting yourself in the foot, or a bit higher. One must realize how small this industry is. Attacking products is not only counter-productive as it causes of loss of credibility, but it can misinform those who are trying to learn as well as damage what is left of a tiny industry. You may want to check this with some notables in the industry and not just take my word for it.

To your question. Is the Strain Gauge designed to conform with RIAA – of course it is. Please review my credentials in the industry as engineer at RAM audio, Director of Engineering at Bozak, Senior research engineer at the IBM T.J. Watson research labs, and owners/design of Soundsmith for over 38 years where I have taught and produced many speaker, amplifier, preamplifier, and cartridge products, including now over 40 magnetic cartridge designs.

I am aware that I have “stupid” tattooed on my forehead, an event that happened many years ago in a Galaxy far, far away that I do not care to be reminded about. But why would I go to all the trouble to produce a cartridge and preamp system that doesn’t conform to RIAA? Suicidal maybe???

RIAA conformation. I own and use two Neumann Lathes for a charity project called DirectGrace records. It is intended to rescue children from forms of slavery, including child prostitution, something that occurs as I sure you are aware in large numbers in Mexico City. The Neumann lathes have “adjustments” for RIAA to keep the system tweaked to “conform” as it can and does drift. So do the lacquer masters on which we cut, which change the response. So does the plating and stepped processes to make a stamper, as do the vinyl and pressing parameters used make a record. You may want to speak to real folks like my friend Lincoln Mayorga, who well understands how this arduous process can lead far off RIAA. But I deviate more than .1 dB –

Tone arm interactions can vary RIAA performance quite a bit. So what do you have when you are done?? If you are tweaking for RIAA for .1dB, try tightening the headshell screws and re-measuring. Or maybe mass load the headshell and try again. Or adjust the azimuth, VTF or SRA. You are aiming at a moving target. Are you moving your preamp gun constantly??? It seems it is aimed at me right now.

I have measured the SG in many arms, and recently in my Schroder Reference SG, the new SG design (which you did not hear) it was +/- 1dB from 50 Hz to 12K in conformation with RIAA. And you know what?? I cried when the record was over.

The rest is magic. ""


""  Elsewhere in the article he says:

"We can now state, with an excellent accuracy level, that the natural
frequency response curve of the SOUNDSMITH cartridge is equal to the RIAA curve, this is so
much true that it is not necessary to equalize the output as normally happens with the standard
magnetic cartridge ""



Kirkus that technically is second to none and exparienced gentleman with common sense posted:


""""  But today, we're all trying to get that absolute last "n-th degree" of performance from our turntables and record collections, and we have more high-quality cartridges (both new and old) to choose from than ever . . . so you have guys like Raul that feel the only way to truly hear what a cartridge and tonearm have to offer, is to get the electronics so precise that they're completely out of the picture. I agree with him, and applaud him for his efforts.

BUT we also have a guy like Peter Ledermann, who has developed a strain-gaugecartridge system . . . and this system is AMPLITUDE-sensitive, NOT velocity-sensitive. And this puts the strain-gauge system in a unique position, because it may actually be the first time in over fifty years that there has been serious development in ANY ultra-high-performance, amplitude-sensitive phonograph pickup. And of course, the concept of "absolutely correct RIAA equalisation" is completely non-sequitur to an amplitude-sensitive cartridge . . . and this has ALWAYS been the case . . . we've just all forgotten.

So to the question of, "does the Strain Gauge system feature extremely accurate RIAA compenstion?", the answer is "of course not - that's for magnetic cartridges!". And to the question of "how accurate is the frequency response of the Strain Gaugecartridge/preamplifier combination for RIAA-standard records?", Mr. Ledermann's response is something like "very accurate, when compared to other [conventional] cartridge/preamplifier combinations."

Peter admits the tolerance exceeds +/-1db but refuses to quantify this variance. He seems to prefer simply tell us it doesn't matter. Peter is beyond brilliant, but I just don't get this approach.

I can't speak for Peter, but keep in mind that if a phono CARTRIDGE actually measures +/- 1dB from 50Hz to 14KHz . . . this is quite flat, for any design. While it's true that a properly-designed RIAA phono PREAMP can (and IMO should) itself be better by at least a couple orders of magnitude, once you add the cartridge and measure the two of them together, then the tolerances are entirely different. The Soundsmith straingauge cartridge is sold as a cartridge/preamp system, so if you want to compare it's response flatness with other products, then you have to compare it to other complete cartridge/preamp combinations, not simply to a preamp on its own. """"


PL follows:


"""  The Strain Gauge is a DISPLACEMNET device, not a velocity sensitive device like all magnetic cartridges.

Velocity sensitive devices have a FLAT playback response, so they require RIAA EQ to invert the RIAA recording characteristic used when making masters for record production. RIAA has an interesting evolution; Mr. Galo has written a wonderful explanation of how, and why it evolved and changed over the years:
http://www.smartdev.com/RIAA.html

Displacement devices have an INHERENT 6dB/octave curve, very similar to the RIAA (not an accident, BYW)....they DO deviate slightly from the RIAA at two points, BUT, we do NOT correct for this, for doing so would ruin the beauty and simplicity of the device; the one super clean gain stage between you and the music we designed is almost one too many. More than one (to "fix" small anomalies) would be death to the magic ""

unfortunatelly that link disappeared. Never mind.


following for this @atmasphere  post:


" Hi Peter, the RIAA curve is flat from 318 uS to 3180uS. So there are about 4 octaves that will be spectrally incorrect. That is a lot bigger error than any room I've tested. BTW I've run plenty of room curves over the years- especially at shows. I agree that you see big variations, but not like this (at least not so far anyway).

I've also produced a variety of LPs over the years and I've found that only 1 db variations in the test pressing can be audible (this is easy to hear over a frequency spectrum as opposed to a single frequency, BTW).

So- do you offer an equalizer? "


P.L answer:


""" 
Thank you for your comments: they are greatly appreciated.

The subject of human response to amplitude and phase is an interesting one; the standpoint often determines the course of design choices for those of us in the audio design and manufacturing field. I, for one, strongly believe that the human ear is much more forgiving in the amplitude domain than it is in the time domain. After all, many amplitude deviations are the direct result of phase interaction due to resonance, both summation and cancellation, making "amplitude" perturbations audible and potentially objectionable in speaker drivers and cartridge/tone arm systems.

From that standpoint, the cutter heads models also vary considerably; many require one or more frequencies to be fed back with control of both amplitude and phase to stabilize the cutter head. The phase shifts introduced by the RIAA recording curve are further modified by the varied individual characteristics of the equipment used to cut the master. So, where does that leave us? The Strain Gauge is without much phase shift at all. If one leaves out the phase shifts normally introduced by use of a playback RIAA curve, is one better or worse off??


Please also refer to the graph near the top of Mr. Galo’s excellent article called Figure 1;

http://www.smartdev.com/RIAA.html

It refers to this graph as the “typical” RIAA response; in reality, it is far from the “ideal” response that one gets from the theoretical filters due to interaction of those filters. This, not the “ideal”, is what we have all been listening to for years with magnetic cartridges! Superimpose a 6dB/octave curve (Strain Gauge) and you will find that it deviates less than plus or minus one dB.

My experience is that severe phase perturbations over a narrow region are very audible, while those that are spread out are much less objectionable. It may well be that this is one of the positive differences one experiences when listening to the Strain Gauge. That, in combination with the general standpoint of multiple stages being inferior to a single stage, makes one think that possibly that too, is a motive for using a "simplified" strain gauge system. There are also numerous other contributors to good sound - extremely low stylus jitter being one.

Although some Strain Gauge preamps in the past have been made to more closely follow the RIAA, some were not. As far as I am concerned it is an open issue that will be addressed from varied standpoints, some of which I have mentioned above. My consideration in the Soundsmith Preamp is to make it mostly flat; the decision to mainly use the inherent 6dB curve of the Strain Gauge elements is based on 35 years of listening and talking with other designers and SG owners. It also provides a standard from which one is not precluded from adding what they believe to be proper EQ to our system, or Soundsmith offering such in the future to those who want it and do not feel that it detracts from the listenability. ""



@atmasphere  posted next:


" So no EQ unit then. If you refer to Stanley Lipshitz's paper, presented to the AES back in the late 70's (arguably the definitive paper on RIAA equalization), it is possible to design an EQ network that will follow the mandated curve correctly, easily better than 1/2 db. He presented very easy formulae to work out practical and accurate values.

It seems that at the upper end of the 'flat area' of the RIAA curve (318uS), that a simple 6db/octave EQ will be off by nearly 24db. "


no eq. that was the version I listened at Boise vetterone home place.


Pl. final post:


"""  I am also concerned that your figure of 24dB is very far off from the reality of the device; it would make it unlistenable! Please observe the "real" RIAA curve in Galo's figure 1, and superimpose a 6dB/octave line on this "real" world RIAA graph, referencing both at 1Khz. The greatly simplified result is that in the response below 1KHz, the SG would be slightly boosted, and above 1K, slightly attenuated. For a cartridge with 70Khz bandwidth and immediate speed of the Strain Gauge, this slight upper end attenuation is not missed at all as there is a definitive acoustic signature that many notice, which more than makes up for this slight "loss".


Noise issues:
When you say, "....allure to the idea of a cartridge that can put out a volt or two." are your referring to the Strain Gauge? If so, that would be an incorrect attribute for the Strain gauge. While ceramic cartridges (displacement devices as well) DO output high voltage, they are also high source impedance devices. The Strain gauge is absolutely neither of those, although I run into many who do think it is. The source impedance is a fairly low, purely resistive 1000 Ohms, and the current supplied is 4 milliamps. The amount that the element varies is less than .1%; this means that the change in voltage is in the range of 3 - 4 millivolts, requiring a gain in the high thirties.

Noise?? In fact, the RIAA EQ inherently reduces high frequency noise and distortion in "normal" preamp circuitry; making RIAA a Dolby of sorts. The absolute requirement for a fairly flat (EQ or not) preamp for the Strain gauge was a bit more problematic 35 years ago, as we had to create low noise circuitry for this "flat" preamp to avoid excessive noise compared with a standard RIAA preamp! Creating a circuit in this day and age with "ultra low noise and immeasurable distortion" is a joy, and very do-able. I would rather listen to this one gain stage and an ultra fast cartridge than anything else  """



We have to read all the whole " history " that 10 years ago explain the ram tubes " black thread ".


Unfortunatelly for me in those old times I was not willing to learn not from P.L and not from Kirkus. My mistake, big one.

Rgerads and enjoy the MUSIC NOT DISTORTIONS,
R.














" 

with all the discussion on the RIAA curve, would suggest real vinyl philes consider the following; test your LP playback set up and see if the playback response is flat according to the RIAA spec.

To do this test, you will need a NAB RIAA playback disc or similar, and a dbm meter or volt meter.

play each freq on the disc from 30 hrz to 18khz. Write down the  DBU or voltage output on your phono stage for each test frequency. you may have to repeat the test until you get the hang of it.

 Transfer or copy the voltage or DBU data into excel and generate a plot.
Scale the Y axis accordingly.

You will quickly see what the true response is for your phono cart, phono stage and turntable set up.

Learned this from an old broadcaster engr friend.

Have measured over a dozen phono/table combinations; some are close but none I have measured were completely flat. Rising top end among MC carts is quite common. This is also a much better way to establish MC cart loading than doing it by ear. Once you have two measurement points with the known cart loading resistor values, you can run a simple calc to estimate what the desired R value is to bring your MC cart into a flat range. 

if you can tweek the values to get the response within 1-2 db across the whole freq range, you will be shocked at how much better your records will sound. Much more like high speed tape....

best

@solypsa mentioned cartridge design. I would like to learn more about the design of a strain gauge cartridge as it seems to me eliminating the EQ is a good thing.

A strain gauge usually employs a power supply which puts a bit of voltage across a sensor usually piezo in nature- similar to a crystal. The power supply voltage is imposed across the sensor, whose resistance changes with the strain imposed on it (in this case by the stylus). That change in resistance with a voltage across it means that the voltage is thus the audio signal.

To say that it does not need EQ is inaccurate. It is more correct to say that will only be slightly off of the required RIAA compensation. It would need less EQ than a magnetic cartridge and with the EQ will still have plenty of output so no phono preamp would be needed.

Ramtubes 3-1-2019

Here is something to consider. What if we didnt use RIAA or any EQ in making a record. If we recorded a constant voltage sweep from 20 to 20Khz and looked at it under a microscope what might we see? When we played the final product what would a voltmeter connected to the speaker (or elsewhere) indicate from 20 to 20 KHz.

Choose your cutter wisely and state if it is amplitude or Velocity. Even better do both.

In modern times, at least, cutter heads and the vast majority of cartridges are nominally considered to behave as velocity transducers. I believe that you (Roger) attested to that in the deleted thread.

**If** both transducers were to conform to a theoretically ideal model of a velocity transducer, the response of the cutter head (in terms of groove excursion) would fall at 6 db/octave, the response of the cartridge (in terms of output voltage) would rise at 6 db/octave, and the falling response of the cutter head would be cancelled out by the rising response of the cartridge. So in that hypothetical situation, with no equalization having been applied either in the making of the record or in playing it, the voltmeter you referred to would indicate constant voltage from 20 Hz to 20 kHz. And the excursions of the groove on the record, as viewed under a microscope, would decrease in amplitude as frequency increases.

However, Ralph stated toward the end of the deleted thread that the behavior of both transducers differs considerably from those idealized models, and I certainly have no reason to doubt that. I am not in a position to comment, though, on the manner or the degree to which those deviations from idealized behavior would change the results I’ve described for idealized models.

Best regards,
-- Al

@uberwaltz: I said there were 3 experts, but I never said I agreed with any of them or that their opinions were the only valid ones. I just happen to feel these 3 people have the most to offer to the discussion and they are people whose knowledge I respect, perhaps more will join in.

Furthermore, as you noted that was my opinion, if it’s a free forum as you say then my opinion is as good as anyone else’s, and as you further state, as long as it complies with forum guidelines, which I believe I have.

Now back to the discussion:

@solypsa mentioned cartridge design. I would like to learn more about the design of a strain gauge cartridge as it seems to me eliminating the EQ is a good thing.

Dear @ramtubes : I did not avoid  digital/vinyl but the other way around because first than all I’m a MUSIC LOVER, it’s with I’m " married " not with source media technology or system hardware.

R.

@ct0517 The thread was closed by the author. 

Clio
That is somewhat pretentious don't you think?
Who gave you the right to decide there were only 2 or 3 "experts" whose opinions are all that is valid here?
Your opinion maybe but still as has been stated many times this is a free forum and ALL opinions are welcome as long as they remain within the posting guidelines of this forum.
Whether you like them or not or agree with them is completely irrelevant.

Here is something to consider. What if we didnt use RIAA or any EQ in making a record. If we recorded a constant voltage sweep from 20 to 20Khz and looked at it under a microscope what might we see? When we played the final product what would a voltmeter connected to the speaker (or elsewhere) indicate from 20 to 20 KHz.

Choose your cutter wisely and state if it is amplitude or Velocity. Even better do both.

I'm interested in vinyl replay. If this thrread is to be useful, imo, the purpose of the discussion needs to be better defined.

Is it theoretical? A discussion on why what was decided 70 yrs ago was?
Is it to better replay technology and implementation? If so stating some areas of focus will be required (such as cartridge design,  phono eq design etc)
Is it to commiserate on how tricky this all is?

@ramtubes, let the other thread stay dead and if this one keeps going the way it is kill it too.

@ramtubes thinks that he discovered the " black thread " with those 12 dbs and said that manufacturers not understand it.

@rauliruegas: I don’t think Roger ever said he discovered the black thread as you say, and it was pretty obvious in the last thread that many disagreed with his theory anyway.

However it does appear that perhaps Roger and Peter Ledermann agree, so there’s that at least. It would be nice if Peter Ledermann joined the conversation as it would be interesting to hear his thoughts and add another expert to the conversation bringing the total to 3 in my opinion.

It’s really hard sifting through some of this stuff (as it was in the last thread) to get to the posts of two (or three) people whose posts you want to read. I wish Audiogon would let me filter out the "noise" so I can just read what I need.

@rauliruegas   I'm an analog lover and MUSIC lover

I am curious how you avoid both digital and vinyl. That leaves tape.

Dear @ct0517 : Everybody knows the SS strain gauge must be connected with its dedicated preamp and I have the threads where PL explainded ( first version. ) why does not needs eq., even in that thread Ralph ask about and concluded that use no eq..

The idea to connect to an aux in a line stage came in the deleted thread only " thinking in high voice " and only to " see " what happens. At least I would like to try it because PL measured a really low inverse RIAA eq. deviation: plus,minus 1db. Yes is really high against the normal 0.1db achieved for today best phono stages but as I said in the other thread it has two big big advantages to put in the scales against that 1db devuiation that are: no inverse RIAA eq. heavy degradation to the carrtridge signal and no need of additional gain stages that adds more signal degradation ! ! !

For me both advantages makes a paramount differences. PL is rigth when he said that our ears are way more sensitive to time errors ( as the ones in any filter and the RIAA eq. are filters. ) than amplitude ones .

@ramtubes thinks that he discovered the " black thread " with those 12 dbs and said that manufacturers not understand it. Well, in this forum PL talks about 10 years ago that’s where I took my conclusion on the whole subject and not because ramtubes as he could think.

In the other side and this is for you @ramtubes and as @almarg posted but I will say in my own words:

you are not the owner of your thread or OP and if you posted then any one including @atmasphere has the rigth to post what ever he wants in the same way that you have the rigth to post anything or say anything even if is contradictory to your own posts in between like happened in the other thread.

Like me and any one in this forum you are onlyy a single one/other gentleman and nothing more than that. You are not better than almost all here as you think and exist a fact that proves you are not and that fact is that you design tube electronics when tubes ( no matter what. ) can’t honor MUSIC but you don't know yet.

""" our local club is about 50% vinyl, "", so what, digital is way superior to LP but things are that that 50% of your club that includes you are just wrong but you don’t know yet all of you are wrong and I can prove it. Maybe in other thread because is off the topic here. Btw, I'm an analog lover and MUSIC lover.

R.

Hi Admin
Thanks for responding. 
Ramtubes (Roger) looks like there might be an option.
Anyway, as you are the OP - its your call. 
I would contact Admin by PM to decide its fate. 

Tammy, here is a link to the deleted thread that has been referred to above by ct0517 and others:

https://forum.audiogon.com/discussions/how-does-riaa-pre-emphasis-work-on-reducing-record-noise

Best regards,
-- Al

@ct0517 What is the title of the original Thread? 

I am not sure if locking of a thread is even an option. If Tammy Audiogon Support sees this maybe she can confirm either way.

Roger - the posters comments were along the lines of connecting the SG Cart up to his own personal preamp, first using the phono input, and then if I recall using the AUX input; with no mention of Peter's preamp. This is an incorrect setup. As I understand, Peter's unique preamp goes hand in hand with the SG Cart, cannot be separated. Based on my limited knowledge of them, his SG Cart and Preamp appear to be - "real thinking/ design out of the box". 
  
As far as how it is eq'ed, maybe you can get Peter to provide his input here since you have talked with him already, so we can have sharing and learning by all of us. That would add a lot of value for me. On a thread like this I am looking to learn. FWIW - I find the available online documentation for RIAA inconsistent, confusing, misleading, incorrect data .. no wonder, imo, it is difficult to grasp when we have experts like yourself contradicting words and terms we have read online..... trying to fill in the blanks. 
 
A definition of terms for important Words would help to fill in some blanks.   

Like for example - Constant Velocity, Constant Amplitude

sorry I didnt know about Locking. However, in my opinion the original thread was an embarassment to all. To take a simple technical question/concept and bury it, as it had been, with opinion, off topic commentary and an argument between myself and Ralph that was going nowhere deserved to be burried. Each post was more disheartening than the previous.

Do you recall what the incorrect info concerned? Of course his preamp is unique, it employs RIAA plus amplitude EQ not RIAA plus velocity EQ.

^^^
Roger
I contacted Peter myself by email, this week,  for clarification on his SG cartridge and unique preamp. I did this because there was incorrect info posted on your other thread about his product. He confirmed some things for me. I was going to publish corrections but your thread was deleted .....not locked. Locked would have allowed viewing without input.  

At this rate I doubt this post will last long. We are already off topic. 

Sorry if you miss the old post. Several members posted such long and confucing replies I could hardly get through them myself. 

I have nothing to gain here. Im not going to win a prize if I am correct. I chose this topic because vinyl is on a comeback, our local club is about 50% vinyl, we have phono preamp "shootouts" which take a great deal of time and effort to set up. We want to know first if we are listening to a preamp with more than a few dB of RIAA error, so I check for that as I am matching levels.

Wouldn't it be nice to know what RIAA is? Is there anyone here who would like to have a go at explaining RIAA to me. I am all ears.

I had a nice half hour conversation with Peter Ledermann of Soundsmith today. We agreed this is a difficult concept to grasp.

I decided that if Ralph wanted to have his own discussion about RIAA he could most easily start his own post. It is clear we will not agree anytime soon.

As others have pointed out, a forum is for discussion.
As for :

behavior was not polite nor was a lot of the information correct

I, for one, found none of the responses to be such-Actually, quite to the contrary.
In fact, the only 'impolite' responses seem to be coming from you.
B

@cleeds  I agree. I followed the thread closely, even though I never commented in it. It's unfortunate that now no one can follow that discussion.

I am glad you were following the thread. I am happy to keep it going here if we can get on track and stay there. I would like to see more participation from those who agree with my assessment of RIAA. All I was getting is unsupported disagreement no matter what references I cited, graphs I linked or logic I employed.

I decided that if Ralph wanted to have his own discussion about RIAA he could most easily start his own post. It is clear we will not agree anytime soon.

@test It's too bad that the previous thread is now locked as it contained a lot of insightful and useful information. I personally get more from a discussion than I do from a lecture.  

The problem with the previous thread is that is that the behavior was not polite nor was a lot of the information correct. Many of the responses were unclear as to what the participant wanted to know.

Did you learn that RIAA EQ is a 12 db boost on recording and a complementary cut on playback?

Did you learn that the 40 dB curve we are accustomed to seeing is RIAA plus magnetic cartridge EQ?

I do hate to say so but I tend to agree with Mental and Almarg.
You truly cannot create a thread that has an obviously contentious topic and then get upset because there are a lot of opposing views and posts.
I am still not sure how much I actually learned from the last go round ( bar the fact that put 10 audiophiles in the same room and you are likely to get 10 different opinions!).
However it did contain some potential useful knowledge but deletion was not the answer imho.