RIAA, Questions only please

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.

@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?

@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.

@rauliruegas   I'm an analog lover and MUSIC lover

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

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.

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.

@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 

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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.

@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?

@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. 

@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.

@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.

@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.