Topic: Trim knobs and Using them

[willndmb]

i think i have this right but i am not sure
i just got a fr-2le and it has trim knobs (although my question applies to any device with trim)

here is what i am thinking...
i plug in the mics and everything
i set the gain where it needs to be
tape away
HOWEVER
if i set the gain and it is down as low as it goes, the signal might be to hot still
this is where i use the trim knobs to cut down the signal more

is that the correct way to "see it"?

thanks

[mikesalvo]

wow, that was fast on the delivery of he new gear. Nice new sig! 

[willndmb]

thanks mike
you should be able to change your sig today

[DSatz]

> ( ... my question applies to any device with trim)

There's no one general "right answer" because sometimes the thing which is supposedly just a "trim" control is actually the overall sensitivity control for the input stage; other times it really is just a small variable boost later on in the circuit, and is mainly there to help you optimize your recording levels, as you might expect.

You need to set good levels without overloading any stage of a recorder (input, intermediate, final, whatever), but the meters usually only tell you what's happening at the final stage of recording (i.e. at the input of the A/D converter). That's always a problem, and with different sets of equipment it has to be worked out differently. Sometimes you have to pad a signal before sending it into the recorder in the first place (like when people get clipping even when their peaks are only at -10 dB).

--best regards

[willndmb]

hhhmm thanks
would you suggest poss...
"trimming" the mics at say -20DBish and then upping the gain to reach the end db setting?
the fr2le has a min of -10db trim

and i have never had trouble before with the 480 > ua5 (no trim) so i assume i would be ok at the -10 for most shows

[DSatz]

willndmb, it all depends on the gain structure of the recorder and the signal levels coming in from the microphones. Since I don't know these things, I can't possibly tell you the right answer. It's just not a situation that allows for general predictions or general advice--at least, not if you want the predictions or advice to be worth relying on.

Someone needs to connect a tone generator to that recorder to figure out how its gain controls interrelate and what the overload limits are in various settings. And someone needs to know how much voltage your mikes put out at the maximum sound levels that you're likely to ever try to record. Only then can anyone figure out what the rules are and what the optimal settings would be.

Or you can use trial and error--but then errors had better be acceptable, because you'll probably have some.

--best regards

[willndmb]

thanks

[esteyes]

from the manual

When you make recording using an external microphone connected to the [ANALOG IN] XLR
connector, adjust the input gain using the appropriate [MIC TRIM] control. Note that the
[MIC TRIM] controls are not effective for line input sources (connected to the [ANALOG IN]
phone connectors) or the internal microphones.

more

Using the [MIC TRIM] control, you can adjust the input
gain appropriately to accept a signal between -50 dBu
and -10 dBu.

and finally

Especially when you record a microphone signal, adjust the [MIC TRIM] control appropriately
so that the [MIC PEAK] indicator on the level meter does not light.

so it would appear to me that TRIM is designed to be the first stage of gain in the unit.
it is the gain for the mic pre, then LEVEL is the amount of signal from the mic pre that you wish to feed to that channel (aka bus).

set the TRIM first, then set the LEVEL. you have now have the best possible gain structue to minimize noise ands distortion

neil

[Jamos]

Since the FR2LE has those mic peak indicators, you should make sure that you've adjusted your trims to be a good bit under where it makes those led's start to light up.  Every situation will be different, but you should get a decent idea of where they should sit after running it a couple times.  I never recorded any PA's with mine, so if that's what you're doing I can't really suggest a starting point.

If those peak indicators are lighting up, even if your main levels are not clipping, you'll most likely hear the signal distorting. 

I don't know if you've ever used a mixing board before, but you can think of these like channel strips if that helps get an understanding of the signal flow.

When I had my FR2LE it was able to be run pretty wide open in most circumstances (i.e. the trims @ 2 or 3 o'clock).

Another tip is to mark the little indicators on the trim knobs with a bit of paint or marker (i used silver sharpie ink) so that they stand out without having to look really closely.

[willndmb]

page 60/1 haha for some reason it didn't hit me the 1st time, thanks for pointing it out it makes sense now
+Ts