Hi all,
Complete novice just purchased equipment, including a mixer Numark DM950 the question is how high should I set the two trim knobs, instructions booklet only detail them as the pre-fader audio level.

Depend on which knobs you mean, I am guessing you mean the channel sliders, you'll have 2, 3, 4 of these, and one pair, usually red marked MASTER.

The channel slider determine the volume of whatever is plugged into that channel, whereas the master determines the volume of the whole 'mix'

Hopes this helps a little

Normally I set the Trim/Gain knobs so that the volume on that channel illuminates the first orange light on the LED output meter. Then I set the Master knob so that the volume of the whole output illuminates the first orange light on the LED output meter of the Master Channel. This way every track is played at exactly the same volume.

Yours is a very basic mixer though and has no LED meters so I'm not sure how you're going to set them correctly. I suppose you'll just have to play it by ear and set them after you've brought the track in. With LED meters on every channel you can set the volumes before you bring the track in ensuring a smooth transition to the next track with no obvious volume changes.

They are there essentially to match each channel so they all output the same volume for a particular slider position.

May sound odd at first, but remember not everyone uses the same source:
Two channesl may have a CD input, another may have a phono deck connected, yet another may have a laptop plugged in - and all these may be feeding in different signal levels.

One way to set this up is to determine the quietest input signal and set the trim on that channel to maximum.
Adjust the others to produce the same level as that first one for a given slider position - this will involve turning the trims back somewhat.

Others will have other ideas on this, but this is essentially what the trim control is for - nothing magical.

the best way to set this is to have the mixer pluged in and your audio sourses but no amp and speakers.

set off audio playing on each channel seperatly and set master and slider for that channel to 0db.

then turn the trim button up til the clip or peak light illuminates then back it off til it extinguishes without flashing.

job done

if you rqire less audio eg background music bring down your master sliders not your input slider.

Paul

Each to their own

So what happens when the speaker requires a microphone, you have faded down the master, so the volume for everything will be reduced, far better to fade down the channel, and keep the master at the preset level, so if a microphone is required it will be heard.

then you trim your mike channel to suit.

The way I do it:
Set the master fader/knob to 0db
Set the channel trim so that you are hitting 0db on the output when you are using the pre fade listen/cue
This way you will be getting the same level when your channel fader is at 0db and the best signal to noise.
Your processing /amps will also be getting the correct input signal.
Hope this helps

thats what i said lol

I beg to differ,you should not run your signal levels up to peak or clip and then just back them off a bit,as this has the potential if you get any transients and are not using compressors or limiters to get a dirty signal down the signal chain,with potentially expensive results
Just run things at 0db.
As the reverand would say "I'm off for a lie down"!!!