strange volume trouble

[Richard Crowley]

But when we turn a knob to control something logarithmic (sound level, light, pitch, etc.) having it behave in a logarithmic manner is very difficult to control. That is why log pots are used: to “linearize” the control function.

[Bill Davis]

Not to put to simple a point on this, but from the original post, it appears your problem might be something as simple as someone having skipped the all important step of setting up the mixer to a proper GAIN STRUCTURE.

For the new folks here – here are the steps. They are as REQUIRED for using an audio mixer, as setting a proper WHITE balance is to shooting proper video.

FIRST – and foremost – check that the channel strip INPUT PAD is set correctly – Mic level signals and Line level signals are VERY DIFFERENT in amplitude. If this initial strip control is set incorrectly, you WILL have a mess of a time setting up your gain structure. (Note: this COULD cause the specific symptoms in the original post in this thread -If the channel strip is expecting a LINE level signal but being fed a WAY too low Mic level – ONLY the last part of the log travel of the fader might provide enough boost to get the signal up to the correct range for output.

NEXT: turn the channel’s Trim Control to ZERO – (fully blocking any signal prior to delivering it to ANY fader, EQ, or GAIN slider in the channel strip) and bypass, zero out, or otherwise remove any EQ from that channel strip.

Then, present a KNOWN signal to the channel input – tone at 100% amplitude is IDEAL but music will do.

Then go back to the channel strip you’re setting and SET the gain of the channel slider PLUS, any subMasters and Master gain controls that you’ve assigned to the signal path – until they are in the OPTIMAL Signal passing position. (neither boosting or attenuating a signal) This is the U (unity gain) or *0* position – or perhaps the bold line in the middle of the shaded areas about 80% of the way up the slider travel path.

At this point, the board is set up to pass any signal presented to a channel perfectly – EXCEPT the signal is totally blocked at the channel strip entry point – the TRIM POT.

THEN and ONLY then, go back and slowly raise the trim pot on the channel strip until you have the signal registering at the proper level on the meters and you’re hearing the sound correctly at the monitor stage.

The point is that the “TRIM CONTROL” is set LAST. If you treat the “trim control” as “just another volume control” you’re screwing things up. Because it’s NOT. it’s the Initial signal GATEKEEPER of gain structure and unless each trim control is set properly by using the above step by step process – the entire board may not mix properly.

This is the BASIC step in setting a mixer up to maximize the signal to noise ratio or each channel strip and give you the best control over gain on all channels.

It means you aren’t presenting an overly strong OR weak signal to any channel strip.

The ONLY reason the nature of the trim pots range of control (log, or linear, or anything else) MATTERS is so you can get the signal into the right range for the channel strip to control.

If TRIM is not set properly – than it’s NOT the channel sliders fault if it reacts incorrectly in controlling gain.

AND just as anything but a calibrated monitor can FOOL YOU as to color balance in a video signal – an improperly calibrated mixing board can FOOL YOU into thinking that your signals are flakey.

For what it’s worth.

[Bouke Vahl]

Thanks all.
I’ve tried two other similar units from other brands.
One (i already forgot the name) had the same issues.

I’ve now bought a Steinberg CI 2.
It has better output leves, and a gain know that behaves in a nice human linear way. (turn the knob half down and the volume is half 🙂

80 bucks more expensive while it has only 2 channels instead of four, but it comes with Cubase, and does what i need it to do.

Most important lesson here:
Do NOT buy this kind of gear on the internet just based on specs and reviews.
Go to a VAR, toy with the actual products and then decide what to buy. And buy from the VAR to keep him alive!
(I could get the same unit 50 bucks cheaper on the internet, but my VAR helped me, we’ve toyed for over an hour with the stuff, well worth the price.)

Bouke

https://www.videotoolshed.com/
smart tools for video pros

[Bouke Vahl]

Just for the records.

The (internet) compan i’ve bought the M-audio from (and got it returned) just called.
They tested it and came to the same findings as i did.
They have had contact with M-audio (something mortals have trouble to acomplish), and sending the unit back to them to get it fixed.

I’m really interested in the outcome!

Bouke

https://www.videotoolshed.com/
smart tools for video pros