Effects: Absolute vs Relative?

I find myself questioning this again, and this time thought I’d ask. I do a LOT of vinyl > Digital conversion. I have a macro which mostly busts through the recorded data stream and ends up with a number of tracks.

Some of my recordings seem less than optimal. I wonder if this is a case of me misunderstanding the values of some of the effects?

Some of the effects are clearly “absolute”. Amplify, Normalize etc when set to -1 produced sound levels that are -1.

Others I keep wondering about. For example “Bass and Treble”.

Lets say I have a recording, if I run the effect “Bass and Treble” on it, and set Bas (dB) to 1.5 and Treble (dB) to 2 and apply the effect to the recording the bass levels are set to 1.5/2 respectively.

The question is, if you then rerun the effect with the same values, does anything change, or do the values stay the same?

I’d always assumed they were absolute, but running tests today it seems they might be relative. If the are relative, what are they relative to?

It’s quite possible I’m just over thinking this but when I run/rerun the same settings I can see the wave form visibly change each time.

You are correct. Most effects are relative and cumulative.

Amplify is cumulate unless enter the New Peak Value, or if you accept the New Peak Value (which always defaults to 0dB).

If you enter the same New Peak Value twice it won’t do anything the 2nd time.

So if I run the 1.5/2 Bass and Treble effect twice, the bass ends up at 3 and the treble at 4?

Which of course begs the question how can you establish what the value is before changing it?

In the case of an old mixing desk, you’d put the sliders in position and listen, then change as needed. is the implication that you can only do the same with audacity?

I guess ultimately the answer is yes, since there is no default sound engineering to a post RIAA curve of a sound file. The records and the turntable do the same thing but it depends on how the original recording and plates were created.

Correct!

Usually it’s done by-ear. You should keep a known-good reference recording handy to “keep your ears calibrated”.

Plot Spectrum can show you the frequency content but for this purpose it’s probably not as good as your ears. Different music will have intentionally different spectral content. I think Plot Spectrum is showing the peak of each frequency but it might be showing average or RMS.

There are EQ Matching effects. I’ve never tried one but I doubt they work very well unless you are trying to match songs in the same style by the same band. Even then, it probably requires some tweaking by-ear.

Yes. You should use the effect preview function. And keep an original backup in case you foul things up! :wink:

The RIAA recording and playback curves are “perfectly” defined. I assume the cutting equipment is super-accurate and most playback preamps are very good.

BUT… Before it gets to that point, during mastering the deep bass is usually rolled-off for better trackability. The highs are often reduced too but I don’t know why.

Back in the vinyl days the records varied a LOT at the “good sounding” ones were rare. I think they just didn’t care… The rumor was that classical records were better than pop/rock but I didn’t listen to that much classical. I assume modern records are better and more consistent but I stopped buying records about the time I got my 1st CD player. (Sometimes I digitize one.)

Phono cartridges vary too.

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It’s the same with Audacity.
Note that Bass & Treble may be used as a “real-time” effect in recent versions of Audacity.

Thank you for taking time to tell me what I guess I knew, I was just hoping I’d find some magical solution to.