How Do I Add more RIAA Curves?

[Koukol]

Hi Gale,

I have my turntable connected to a Scarlett 2i2 with some RCA to phono adapters.
I turned up the gain controls to the point where there's no orange flash let alone red.
Anything above that shows the red line of clipping in Audacity every once in a while.
I think my signal is getting in alright since selecting the amplify effect after it doesn't need to be adjusted.

It's after I use the RIAA that amplify chooses to boost the volume.
But as I said... the other RIAA I uploaded preserves the volume so after the amplify effect chooses no change. (above graph shows higher volume)

"If you like you can attach a short sample of the audio: How to post an audio sample or select some audio, open Analyze Plot Spectrum... and attach an image of Plot Spectrum."

Cheers...I'll look into this

[Koukol]

Ok...
I took two screen shots.
Both show a mid-section of a song with one having the Audacity RIAA curve applied and the other the other RIAA curve.
While the other is fine... Amplify wants to correct the Audacity curve by boosting it just over 10db.

[Gale Andrews]

Ok...I have my turntable connected to a Scarlett 2i2 with some RCA to phono adapters.

As you know, Scarlett has no phono input. Is the output of the adapters (the TRS end of the cable) producing line level output with RIAA EQ applied? Or what is the make and model number of the adapter? A "phono amplifier" would do exactly the same as a "phono adapter" as I described.

Or are you deliberately taking the turntable output without applying RIAA and that is why you want to apply the RIAA curve in Audacity? If so then it is expected that applying RIAA in Audacity could reduce the volume, just as it is expected that if you ripped a CD track then applied RIAA EQ to that it could increase the volume.

Ok...
I took two screen shots.
Both show a mid-section of a song with one having the Audacity RIAA curve applied and the other the other RIAA curve.
While the other is fine... Amplify wants to correct the Audacity curve by boosting it just over 10db.

Which is which - the lower image is that of the Audacity curve applied to the waveform, yes?

Can you show the spectrum of that selection before you apply either RIAA curve? And can you attach this "other" RIAA curve? I suspect it is not an RIAA curve. It may be some pre-RIAA curve.

Note that in Amplify you can set "New Peak Amplitude" to what you want, but if you want to end up with the same non-maximised peak volume each time, such as -1 dB, it is easier to use Normalize instead.

Gale

[Koukol]

Here are screenshots of both before and after the RIAA curve.
BEFORE


AFTER


The other RIAA is definitely a RIAA curve...I got from here. (please let me know if I shouldn't post this link)

http://www.nullmedium.de/dev/audioplugins/

I noticed today that this other RIAA requires a boost in signal once applied too...but unlike the Audacity RIAA that requires about 10db it requires only about 1db.
Does it even matter that the reduction from both are so different?

The Focusrite Scarlett 2i2 is a great microphone/instrument preamp...It just doesn't have a built-in RIAA curve to use with turntables.
This is why I need the RIAA curve.

[steve]

Here are screenshots of both before and after the RIAA curve.

That certainly does not look like what I would expect from applying RIAA equalization.
I am not able to test what that plug-in is doing because I am not on Windows.

Have you tried the RIAA equalization that is included in Audacity? http://manual.audacityteam.org/o/man/equalization.html

[Koukol]

Hi Steve,
My last post is the RIAA from Audacity.
The other one doesn't reduce the volume 10dbs.

[steve]

It would really help if you posted a short audio sample in WAV format so that we can see exactly what is going on. Images and numbers will often not tell the whole story. Please post that section 14 to 19 seconds from the "before" screenshot in your last post. in WAV format. (Instructions if you need them: http://forum.audacityteam.org/viewtopic ... 49&t=72887)

[cyrano]

I've experimented quite a bit with RIAA correction in software some years ago, as I had an interface that applied RIAA in software. The most important thing I've learned, is that it is sensitive to the level of the incoming signal.

In a typical Hifi RIAA preamp, this problem is avoided by setting "average" values for gain. Better preamps might have impedance and gain corrections (usually marked MM and MC). It's not ideal, but it works.

When you use a mic preamp, such as the Focusrite, your gain setting is very important. But there is no way to know where in the digital realm the plugin developer set the gain, as he has no way of knowing in which audio editor you will be using the plugin.

I still use "my" RIAA settings to test turntables and pick-ups. I've had to adjust these quite a bit as I changed interfaces a while ago. It's also kind of hard to measure, as there is no absolute voltage reference in the digital realm. When doing it in the real world, you'd get numbers by the cartridge manufacturer and measure the output of your preamp to set gain accordingly. I see no way of doing this digitally. If anyone has any ideas, they are most welcome

[kozikowski]

A phono preamplifier doesn't just amplify the sound and remove the RIAA distortion. It receives the signal from the cartridge in a very specific way so as not to distort the sound any more than necessary. If you "look into" a Phono Preamp connection you should "see" 47K-ohms resistance with 100pfd capacitance (from memory). Other types of connections are most unlikely to hit that standard and if you don't hit it, the system will not play back the RIAA music correctly.

Just seeing we're on the third forum chapter with this means you may not be a candidate to "fudge" the connection.

This is not rocket surgery.

http://www.sweetwater.com/store/detail/UFO202

Koz

[kozikowski]

If you have an analog amplifier that has a phono preamp in it, use that. This device can be switched to straight line-level audio to digitize the amplifier's corrected show.

Koz