noob question: volume and trim

  • Thread starter Thread starter billbone
  • Start date Start date
B

billbone

New member
ok, this is a question I'm ashamed to ask - I know it's common knowledge, but I must have missed this day in class.... I never became a student of recording, even though I really enjoy doing it.

I use Sonar 3, and when I record, I kind of do it hap hazzard - I try to keep the volume and trim on ZERO, and get decent volume out of my instrument and direct box. When adjusting the track in playback, I turn up the volume. If that's not enough, I turn up trim.

Now I'm sure even though this works most of the time, I'm missing the real value and meaning of Trim. What is the purpose? How should I balance trim and volume.

Thanks...
 
YOu should keep the volume and trim at 0 in Sonar. You should set the recording level with your preamp or mixer on the way into the computer.

You should set the levels so the meat of your signal is right around -18dbfs (or 0dbVU in the analog world)

The faders on a mixer (real or virtual) have much more resolution around the 0 mark (unity gain). YOu use the trim control to bring the level of the signal up or down so the fader can be set in that area. You end up with more control that way. In a DAW, the trim is also used to get a more favorable signal level to the insert plugins.
 
A signal path includes a series of "gain stages" (familiar with that term?)
Trim and Volume are two gain stages in your path. Trim is the first gain stage which, on a console for example, controls the signal coming from the mic-pre. Volume would be the Fader on the console. Basically you're just adjusting the level of the signal at different points (hence "gain stages") in its path. It's good to strike a balance so you don't have your trim wide open and your faders all the way down, for example. It would be possible to get more involved here, but hopefully this was helpful.

Ultimately you don't need to worry about which knobs you grab in Sonar, just track/mix it to the levels you want.

Just curious, how are you getting your direct box into the computer?
 
i'm using sonitus TubePre, and the output goes right into my mic line in. everything really seems to be OK, but I'm still looking to micro manage everything, and that's why I thought to ask.
 
So your path is:
Instrument ---> TubePre Instrumet In --->TubePre Line Out --->Computer Sound Card Line In?
A Direct Box is used to convert Instrument Level signals to Mic Level. At first I thought you were using a direct box into a Mic In of an interface, but now I'm with you.

You should try to strick a balance among all the gain stages in your signal path, not just the Volume/Trim in Sonar. Although obviously clipping in the analog world is going to be more foregiving than the digital world.
 
billbone said:
... when I record, I kind of do it hap hazzard - I try to keep the volume and trim on ZERO, and get decent volume out of my instrument and direct box. When adjusting the track in playback, I turn up the volume. If that's not enough, I turn up trim.
Click to expand...
Just to mention also, these settings in 'Cake have no effect on tracking volume, only playback.
The good news though is that if your hardware/record levels are in the ball park like Farview mentioned- averages around -18, leaves comfortable room for peaks, your Cake trim and volume levels will fall nicely in line. The faders will be in the nominal zone with out having to even mess with trim much.

Wayne
 
RAK said:
So your path is:
Instrument ---> TubePre Instrumet In --->TubePre Line Out --->Computer Sound Card Line In?
A Direct Box is used to convert Instrument Level signals to Mic Level. At first I thought you were using a direct box into a Mic In of an interface, but now I'm with you.
Click to expand...

umm, actually, yeah... I might have mis-spoke. There is a MIC 1/4" input on the the soundcard, so the TubePre is going into that! I guess it's not really a "Line In". So that's bad? The tubes in the TubePre do a nice job a limiting some room noise, and slightly warm the tone - that's what I bought it for, and it seems to have some effect. But am I using it wrong?
 
billbone said:
umm, actually, yeah... I might have mis-spoke. There is a MIC 1/4" input on the the soundcard, so the TubePre is going into that! I guess it's not really a "Line In". So that's bad? The tubes in the TubePre do a nice job a limiting some room noise, and slightly warm the tone - that's what I bought it for, and it seems to have some effect. But am I using it wrong?
Click to expand...


Your signal levels are way mismatched. In a real basic overview, The TubePre Line Out is going to be putting out a +4 dBu line level signal. There are two different Line Levels (+4dBu/-10dBu), Instrument levels, and Mic level. Mic level is the lowest. For example, you generally don't want to plug a Line Level Output into a Mic In because you run a much greater risk of damaging the mic pre.

So if you're sending your line level output into your mic in on your sound card, you're sending a high level output into a low level input. Is it a built in sound card with a 1/4" jack (sure it's not 1/8"?), or did you buy a new soundcard?

Having said all that, if you're not having a problem with a super hot signal into your computer, then I guess it's working (although I'd be surprised that you weren't getting that problem).
 
RAK said:
Your signal levels are way mismatched. In a real basic overview, The TubePre Line Out is going to be putting out a +4 dBu line level signal. There are two different Line Levels (+4dBu/-10dBu), Instrument levels, and Mic level. Mic level is the lowest. For example, you generally don't want to plug a Line Level Output into a Mic In because you run a much greater risk of damaging the mic pre.
Click to expand...

I have nearly the same setup as billbone (but I am using the Presonus TubePre with an Edirol FA-66 interface). I plug my guitar into the 1/4" in on the TubePre, then I have a short XLR cable running from the XLR out on the TubePre to the XLR in on the Edirol. I use this connection whether I have a mic or a guitar plugged into the preamp. Are you saying that I should be connecting the preamp and interface via 1/4" when recording guitar?
 
Last edited:
bojax34 said:
I have nearly the same setup as billbone (but I am using the Presonus TubePre with an Edirol FA-66 interface). I plug my guitar into the 1/4" in on the TubePre, then I have a short XLR cable running from the XLR out on the TubePre to the XLR in on the Edirol. I use this connection whether I have a mic or a guitar plugged into the preamp. Are you saying that I should be connecting the preamp and interface via 1/4" when recording guitar?
Click to expand...

No that's not the issue. First off you need to seperate your input side from your output side. If you have a microphone, plug it into the XLR mic input. If you have an instrument plug that into the instrument input.

The Outputs on the TubePre are sending out a Line Level (I'm sure +4dBu) no matter what you plug in. Both the XLR (balanced) and 1/4" (unbalanced) Outputs put out the same level. (Output Level and Balanced/Unbalanced are two different issues).

The real question is what type of input do you use the on the Edirol. If you use the XLR Out of the TubePre (+4dBu Balance Line Level), then you should connect to a +4 dBu Line Level source on the Edirol. Using the 1/4" Output of the TubePre will still be +4dBu Line Level, it's just an unbalanced connection.

Make sense?
 
RAK said:
The real question is what type of input do you use the on the Edirol. If you use the XLR Out of the TubePre (+4dBu Balance Line Level), then you should connect to a +4 dBu Line Level source on the Edirol. Using the 1/4" Output of the TubePre will still be +4dBu Line Level, it's just an unbalanced connection.

Make sense?
Click to expand...

Let me ask you this. I just checked the specs for my preamp and my interface.

Preamp: XLR output operates at +4dBu, and 1/4" output is unbalanced and operates at -10dBv.

Interface: XLR input (-50 to -10dBu), and 1/4" input is TRS (-35 to +4dBu)

Does this mean that I should try to connect the XLR out on the preamp to the 1/4" input on the interface? Those seem to be the only two connections that match up at +4dBu.
 
I was wondering if maybe the 1/4" input was operating at -10dBu, but not being familiar with the pre-amp, I just assumed +4dBu on both, sorry for that.
I think you're right about going XLR Line Level Out of the Preamp to 1/4" Line Level In to the Interface. You definetly don't want to plug an XLR Line Level Source into an XLR Mic Level Jack.

Now, you can plug an Unbalanced (TS) cable into a Balanced (TRS) jack, so if you wanted to go 1/4" -10dBu TS out of the TubePre into the 1/4" +4dBu TRS Jack of the interface, you could, but you may not be able to get enough level into the interface (because you're sending a weaker -10 dBu signal).

If I were you I would get an XLR to TRS cable to connect between the two boxes, like you suggested. Just curious, which Edirol model do you have?
 
Thanks a lot for the help. I think I'll go with the XLR to TRS connection. The other connection seems to have been working okay, but I have noticed that my levels within SONAR are really hot compared to what the VU meter on my preamp shows (even accounting for the difference in dbVU and dbFS).

I have the Edirol FA-66 interface and Presonus BlueTube preamp.
 
$ .02

some of the info your recieving maybe partially right and confusing in anycase... so perhaps this will hel and is not specific to your gear... or anyonelses for that matter...
all devices have noise that cant be eliminated...refered to as the noisefloor...so imagine a graph showing your audio with a line of noise somewhere below it... now if we amplify this signal the noise is raised proportionately correct?? but if we raise the audio in the first stage and then amplify the noise is still down in the lower level... with me so far? so by extensionif we go through every peice in the signal path and set it so that the noise is minamal for that stage then it is properly "gain staged" of course all bets are off if you push to the point of distortion (unless thats what you want) so what you want to see basically is as hot a signal as you can get without overdriving the next stage.... and that may mean turning down the input of the next stage rather than the output of the previous....good luck...
 
You must log in or register to reply here.
Back
Top