Even though I actually created a way to alter voladj parameters a long time ago (in conjunction with Picker), the method for altering them in a trial-and-error fashion was cumbersome and I never played around with different parameters. All I did was turn voladj on and off.

Now that Mark Lord has written his kernel to allow easy parameter tweaking (I think we should dub him "Lord Kernel" in the same grand tradition as Levelord), I've been playing with the settings.

My main goal is to get voladj sounding pretty much the same as Richard's default settings, but have it amplify less tape hiss.

Right now I'm using the "low" setting to plug in my own parameters, and I'm playing with the following values:

[hijack]
voladj_low=0x2000,409,0x1000,100,900

Richard's default values would be:

voladj_medium=0x2000,409,0x1000,27,70

Note that I've left everything the same except that I've increased the noise floor from 27 to 100, so that the quietest sounds aren't even amplified. And the "fake silence" number seems as though it's actually more like a "maximum multiplier ceiling" value. So my value of 900 means that if you've got quiet notes buried in tape hiss (such as the beginning of the La Villa Strangiato remaster), it doesn't amplify it so much that the tape hiss becomes obvious.

Anyone else experiment with this much? I'm going to have to play with it some more to see what values work well.

...(such as the beginning of the La Villa Strangiato remaster)

Listening to La Villa as God intended it to be heard (i.e., without VolAdj) I can hear no tape hiss at the beginning until I have the volume on the empeg cranked up to +4 overdrive, and by that time the guitar notes have become almost painfully loud. (listening through headphones connected directly to the Line Outs)

Is VolAdj really performing as intended here?

tanstaafl.

Perhaps a slower "attack rate" is needed for voladj.
Can the existing parameters be used to alter that?

-ml

Yes, the attack rate is adjustable, it's one of the parameters. I think Richard's default attack rate is good.

Yes, voladj is working as intended. The changes in the parameters are things that have improved it (for me) and are working quite well. I was just wondering if anyone else has played with it and has any other interesting insights.

I haven't played with the settings much, but I do know that one track that voladj really struggles with (even on low) is Roxanne by the Police. You get nasty pumping effects as the multiplier varies quickly as a cymbol (with a very wide spread of high frequencies) competes with a single guitar note (with a much more limited range of low frequency components).

Yeah, I could see how it would pump on Roxanne....

You get nasty pumping effects as the multiplier varies quickly...

I too, have experienced strange behavior like what you describe. Very quick up/down action. Most unfresh.

So I'm wondering, is there any way to modify the VolAdj code to read ahead a little bit and try to smooth things out a bit? Maybe do some sort of anti-aliasing on the ramping?

Not sure if this is even possible, just a thought.

Voladj has a limited amount of read-ahead, basically it can only see the data as it is fed to the kernel.

To reduce pumping, decrease the rate parameter (the first parameter). It will then not try to pump as hard.

If it's only pumping DOWN too hard because it's trying to avoid clipping, then you can try changing the headroom parameter (the third one). 0x0800 or 0x0600 should make a difference. If it's objectionable pumping up AND down, then your only option is to change the rate parameter (the first one).

Or a combination of the two might be effective.

Richard.