Stereo Mix + Gain bug & plugin idea

ThJ · Mar 31, 2007, 05:36 PM

There's a bug in the Stereo Mix + Gain plugin. It does something insane to the volume, very loud static on the 2nd input pair when connected to a source with a little background hiss on it. I almost had a heart attack.

SUGGESTION: What about a plugin I can insert in my chain that cuts sound off if the level exceeds [numeric] dB for over [numeric] milliseconds? It could output a [numeric] Hz sine tone at [numeric] dB to signal what's happening. The numerics would be user controllable. I just want *something* to prevent further frightening experiences or even damaged speakers.

Chester01 · Apr 1, 2007, 10:19 AM

either you are talking about a compressor... or a noisegate from what I gathered

a compressor will take the very loud sounds and make them quieter in accordinance to a ratio and threshold you set (threshold= -40 db, the signal is at -20, the compressor will output -30 db with a 2:1 ratio)

A noisegate will have a minimum threshold and a turn on threshold, it will 'mute' the signal if it is below a certain level (say -60 db for the turn off, and at -55 db of signal will turn the noisegate off and allow signal through)

hope this helps!

ThJ · Apr 1, 2007, 10:25 AM

Thanks for the reply, but I already know and use those. What I want is an inverted noise gate, i.e. one that closes above the threshold.

Maddogg6 · Apr 1, 2007, 12:00 PM

Quote:

Thanks for the reply, but I already know and use those. What I want is an inverted noise gate, i.e. one that closes above the threshold.

it doesnt exist I imagine because few would find much use for such a thing.
The closest thing that *does* exist to what you describe is a 'limiter' - and a compressor can act as one as chester was pointing out. Try 'Dynamics Processor' it has limiting presets. It wont add the tones to indicate when it activates - it lowers those peaks instead. (a much more convenient feature imo)

The best solution is to not use the stereo mix + gain as I gather it has a bug.
Instead use stereo mix and individual gainHQ's

OR use mixy - as its channels will allow gain and not just attenuation. Just dont connect mixy inputs to FXbuss lines directly.

the main point is to eliminate things that cause such drastic level differences to begin with.

or - heres a simple (un-optimized) stereo mix w/ gain (x1 - x20)
( (In 1 x (In_1 level)) + (In 2 x (In_2 level)) ) x Gain

Code:

; New microcode
	name "StereoMix n Gain";
	copyright "Copyright (c) 2004.";
	created "04/01/2007";
	engine "kX";
	; comment "";
	guid "4b88d1c1-4c08-4b3f-9101-7d6f221557d6";
	; -- generated GUID


input In_1L, In_1R, In_2L, In_2R
output Out_L, Out_R
control IN_1 = 0x1, IN_2 = 0x1, Gain = 0x0
temp tL,tR,tG

macs tL, 0, In_1L, IN_1 ; tL = 0 + In_1L x IN_1 
macs tR, 0, In_1R, IN_1 ; tR = 0 + In_1R x IN_1
macs tL, tL, In_2L, IN_2 ; tL = tL + In_2L x IN_2
macs tR, tR, In_2R, IN_2 ; tR = tR + In_2R x IN_2
interp tG, 0x1, Gain, 0x14 ; Scale the gain to tG = 1 - 20
macints Out_L, 0, tL, tG ; Out_L = 0 + tL x tG - multiply with tG as an integer
macints Out_R, 0, tR, tG ; Out_R = 0 + tR x tG 

end

The above code works for me - but no warranty is expressed or implied - Im a sucky programmer...

Max M. · Apr 1, 2007, 03:50 PM

>The above code works for me - but no warranty is expressed or implied...

indeed. but yep, this is the bug in gain of stereo mix (that's incredible to see how many ester eggs we can see in very old plugins) - so, ThJ - thanks for the report.
(ha-ha-ha - guys, use GainX - this one is bug free - my word for that

)

ThJ · Apr 1, 2007, 04:09 PM

I'm familiar with conventional studio gear and I know what it can do. Mixy is what I normally use but this was for my barebones guitar setup, where all I wanted was to mix two SRC'es. In the case of a limiter at 0 dB, it would do nothing but prevent clipping on the output signal. It wouldn't do much for the ear deafening noise. Think of my idea as an acoustic fuse. Maybe it could use an equal loudness contour and RMS to measure actual loudness. This thing could also be useful to stop feedback in its tracks.