Constant volume cross-fade

j20056

j20056

Member
I have two amps set at the same volume, but different tones although not very different. I assigned a volume block for each, both assigned to External 1, which is an expression pedal. I set the parameter range of the first amp's volume block to min=0, max=10, and vice-versa for the second amp volume block. The cross-fade works, but the volume is not constant. The graph is a 45 degree straight line for each so I am wondering if I need to use a different curve in order to keep the volume constant, by tweaking the Mid/Slope/Scale/Offset parameters maybe?
Help appreciated.
Unless there is a better approach altogether?
 
j20056 said:
I have two amps set at the same volume, but different tones although not very different. I assigned a volume block for each, both assigned to External 1, which is an expression pedal. I set the parameter range of the first amp's volume block to min=0, max=10, and vice-versa for the second amp volume block. The cross-fade works, but the volume is not constant. The graph is a 45 degree straight line for each so I am wondering if I need to use a different curve in order to keep the volume constant, by tweaking the Mid/Slope/Scale/Offset parameters maybe?
Help appreciated.
Unless there is a better approach altogether?
Click to expand...
You might try a Mixer block after the Amp blocks instead.

Use a similar approach for assigning the modifiers to the Row Levels.
 
j20056 said:
the volume is not constant. The graph is a 45 degree straight line for each so I am wondering if I need to use a different curve in order to keep the volume constant, by tweaking the Mid/Slope/Scale/Offset parameters maybe?
Click to expand...

A straight line for the modifier will produce a volume dip like you're hearing. To avoid that, turn up the "Mid" to about 70%.
 
chris said:
Are both the exact same volume at each extreme?
Click to expand...
yes the volumes are the same at the extremes. the volume is lowest at the mid point. Thinking volume in dB is Log(acoustic pressure), so maybe sum of x*source1
+ (1-x)*source2 is not a constant. I'll fiddle with curves as I don't understand how to use a Mixer block for my use case. Sorry I'm new to this, got the AF3 three days ago.
 
GlennO said:
A straight line for the modifier will produce a volume dip like you're hearing. To avoid that, turn up the "Mid" to about 70%.
Click to expand...
@GlennO: that doesn't work at all. But remember I am doing 0-100 on one and 100-0 on the other. I tried 70% on one and 30%v on the other but no luck
 
OK solved. On the main Volume/Pan screen, there is a drop down called Volume Taper, which defaults to Log20A, which is likely right for a straight volume control. By setting both blocks to Linear instead, and keeping the Mid at 50% and a linear 0-100 line, the cross-fade has constant volume. Thanks all!
 
Yeah, raising the MID setting in the modifiers would also work. Mid to 80% would counteract the default Log 20 taper in the Volume block and give a fairly linear overall response.

Using a Mixer block works as well since the row level controls in the Mixer block are linear instead of Log.
 
To close the loop on this topic; I tried the Mixer block approach and it works. As mentioned above, I can also confirm that the fade is done linearly although there is no option for controlling it. The only negative of a mixer is that for a cross fade, it consumes a row as it needs to sit on a row that is not one of the two being cross faded. I wound up using that approach (because I ran out of Volume/Pan blocks) but now I’m maxed out as there are only 6 rows. So I made it; barely. But my new template thus created has everything I need now including a cross fade for the center channel between simulated dry versus actual dry (from real amp) and cross fade between dry and stereo wet.
Studio setup obviously but awesome.
 
Hummm. Well I had to use a Mixer block because I ran out of Volume/Pan blocks as I needed two cross fades in my preset.
Are you sure about the Mixer issue in cross fade context only? Initially I had it at the end of row 3, trying to cross fade rows 2 and 3 but it didn’t work because when setting the expression to make row 3 silent then the Mixer block itself is made silent which then mutes row 2. Sort of circular reference.
 
I’ll try again tonight but the behavior I observed is that if I cross fade rows 2 and 3 and the mixer is in row 3, then I get no volume when setting the expression pedal to play row 2 and mute row 3. Seems logical as the mixer receives row 2, then turns row 3 to zero..: which includes itself.
I’m curious though. Are you making a theoretical argument or do you literally have the cross fade working? If the latter then please confirm and I’ll try again to save a row
 
I was wrong and I can confirm that the Mixer block works fine if located on one of the rows that it modifies.
 
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