Signal bleed after distributor?

Hi all, I'm seeing an odd behaviour after a distributor. I'm using it to switch between single channel / stereo input in an FX ensemble. I use a button to distribute the signals - with the button set to "on" (button output value = 1) the signal chain is set to stereo, so the outputs of the distributor labeled "0" shouldn't show any activity. However, the mouse pointer hovering over the connection displays odd numbers, and a connected level meter ("Bleed") shows a constant signal of -61dB. Can anybody say what's happening here?

Edit: the distributor's curve is set to "none" in the properties.

 

that would be considered a DC offset, no?

sorry, im never that helpful for audio questions! =(

 

AAre you sure it's not showing "-61db" because you're using a level meter - measured in dB rather than a regular meter to check the output value? The level meter might have a min value of -61dB, so if it's fed with a "0" signal, it's going to report -61dB, because an absolute 0 signal is -infinity dB.

Instead of using a dB meter, try:
Output * 1000000 -> Meter

...where "Meter" is absolute and not dB.

If it's still a problem, please upload a macro.

- Chris

 

that sounds pretty likely! did you try simple wire-hovering?

 

Hi Chris, hi Daniel - didn't notice this one getting replies, so I'm a little late to respond, sorry. However, I first noticed some sort of signal present at the 0 output of the Distributor by 'wire-hovering'. These numbers varied and sometimes even mirrored the same numbers present at the active connection (the 1 output). So that made me have a closer look at what was going on, connecting the level meter (being setup to a range of -40 to 0 dB by default). When the level meter didn't show anything, I lowered the sensitivity gradually until I got to -61dB, at which point the meter lit the first segment. So that was what I did in the first place. Now, when I connect a meter multiplied by a constant of 1000000 - as Chris suggested - I see nothing on the meter, just as it should be. Wire-hovering also shows a "0" at any time, while the connected level meter at the same output is still at -61dB. BUT - and that's probably the root of evil here - once I hover over the active output's connection, further wire hovering then shows the exact same numbers present at the active wire at any of the inactive connections. When I hover the meter-connection once again, these numbers are sort of resetted to 0, and all other inactive connections show 0 as well until I hit the active wire...

While I probably have to accept this as is, I'm still puzzled by the Level Meter and the mysterious -61dB, because the lower I set the l-meter's range, the more segments light up. I always thought a Zero's a Zero and therefore expected to see -infinity dB. I'll attach the macro embedded in an ensemble to demonstrate the wire-hovering strangeness and would be glad to get the level meter thing sorted out. Thanks for your replies.

(oops, forgot to attach the ensemble - here it is)

 

I've got no time to really read all text above but I just want to put your attention to the "curve" option in the properties. I had some "bleed" issues my self once until I found that....

 

That's where I looked first - however, setting the curve to 'none' didn't make a difference. Naturally, since the pos input sees only 0 or 1 in which case no blending occurs. But thanks for poining this out!

 

Yeah, the problem is just with the level meter's representation of a "0" signal. Try setting the "Value" property of the level meter to On, so you can see the value of the meter, and you can see beter what's going on. It's just the way the bars display when the "min" for the meter is set to less than -60dB.

You can hook a constant of "0" up to the Level Meter and see all the issue I'm talking about, you don't even need the rest of the structure.

The moral of the story: GUI drawing modules are more likely to be buggy than simple math-based audio processing modules.

- CList

 

Doh - that simple! Out of curiosity - do you have any idea why this happens specifically at/below -60dB? Some kind of internal resolution / word length?

Thanks again!

 

No, I'm guessing it was just arbitrary when the GUI was being coded, and in fact I'd call it a bug.

-60 is low in terms of audibility but it's not very low in terms of 32-bit float resolution which goes down to.... um.. I forget, but it's < -120dB. It's it's not even low when compared to 16bit integer resolution which goes down to < -84dB.

- CList