How Do I Add more RIAA Curves?

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Koukol
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Re: How Do I Add more RIAA Curves?

Post by Koukol » Fri Nov 27, 2015 6:16 am

Audacity RIAA Applied.wav
Audacity's RIAA applied
(1.47 MiB) Downloaded 27 times
3rd Party RIAA Applied.wav
After other RIAA applied
(1.47 MiB) Downloaded 18 times
Before RIAA.wav
No RIAA applied
(1.47 MiB) Downloaded 33 times
steve wrote: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)
I hope it's alright that I give you another example.

Signal straight from my Scarlett 2i2
Image
After the Audacity RIAA curve
Image
After the 3rd party RIAA curve
Image
Last edited by Gale Andrews on Fri Nov 27, 2015 6:51 am, edited 1 time in total.
Reason: remove unwanted URL tags yet again

Gale Andrews
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Re: How Do I Add more RIAA Curves?

Post by Gale Andrews » Fri Nov 27, 2015 6:50 am

You can just put the image between

Code: Select all

[img][/img]
tags. Don't add URL tags as well.

Gale
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Gale Andrews
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Re: How Do I Add more RIAA Curves?

Post by Gale Andrews » Fri Nov 27, 2015 7:43 am

The plugin README http://www.nullmedium.de/dev/audioplugins/ says "Signal levels with no gain are calculated to give 0dB gain at 1kHz."

The plugin (set to 0 dB gain) applied to 0.8 amplitude white noise seems to me to produce an identical spectrum shape to Audacity 's RIAA curve. The peak in the plugin's waveform after application is +3 dB which is slightly more than the +2.9 dB for the Audacity curve.

Applying the plugin (set to 0 dB gain) to "Before RIAA.wav" gives about 5.5 dB higher RMS and 5 dB higher peak than the Audacity curve. The shape of both resultant spectra looks identical.

When the result of either curve is maximised in Amplify, the audio looks similar but not identical.

I agree it is potentially suboptimal to record RIAA-equalized material "flat" into an interface. You might do it if you had pre-RIAA era discs, then applied inverse RIAA and finally the actual curve that the disc used.


Gale
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Koukol
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Re: How Do I Add more RIAA Curves?

Post by Koukol » Fri Nov 27, 2015 12:34 pm

OK

I'll try a dedicated phono preamp today and won't bother you any more.
Thanks.

kozikowski
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Re: How Do I Add more RIAA Curves?

Post by kozikowski » Sat Nov 28, 2015 12:29 am

Missed one. The other thing a "real" phono preamp does is provide a place to connect the auxiliary shield connection. In English, that's the thin black third wire coming out of the turntable. Note the Behringer unit has a screw terminal to connect that wire. When the RIAA system boosts the bass tones, hum and power interference are likely to come up as well. This third wire prevents that interference.

Koz

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