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Signal Chain / Recording Levels

Discussion in 'Recording' started by BudgetPro, Jan 25, 2009.

  1. BudgetPro

    BudgetPro Guest

    Hi All,

    Just taking the first few steps into the recording world and although im getting reasonable sound something is bugging me.

    I have a condensor mic > pre > comp > mixer > computer. The mic pre has an output level led scale and the compressor an in and out as you'd expect. However, if i turn the gain up enough for the signal to even register on the pre meter (-20db) it is already pushing -3 db on the input meter of the comp. According to the pre's instructions i should turn up the gain until the meter just peaks at 0, but at that level all sounds (even whispering) are well over 0db on the comp in meter.

    The same happens at the next stage as well. The comp out is peaking at 0db or slightly over, but that signal hardly registers on the mixer, so i have to use the mixer's pre to compensate. im sure this isnt how its supposed to be.

    All equipment is set to -10. I have tried everthing set to +4, but it was the same story.

    Am i missing something obvious?

    Any help would be greatfully recieved.

    Cheers
    CC
     
  2. zemlin

    zemlin Well-Known Member

    What happens if you run the pre directly into your sound card (set the pre at -10dB, if that's an option). Do you need the compressor and mixer inline at all?

    If you really want the other bits in there, it sounds like a gain staging issue with the compressor and/or mixer.
     
  3. Codemonkey

    Codemonkey Well-Known Member

    Your mixer is adding noise.

    You use it for EQ or headphone tracking?
    The former -> get a decent EQ plug.
    The latter -> use a splitter.
     
  4. Boswell

    Boswell Moderator Distinguished Member

    It would help if you gave the make/model of the various components in your chain.

    You should run all the items at +4dBu balanced unless you have a very good reason for not doing so. The mixer will have variable inputs and not be input switchable -10/+4, and you would expect to have to use some gain there when driving at -10dBV [But see below..] Don't forget that 0dB is relative to each particular piece of gear and not an absolute measurement like 4dBu, so there may be no matching of nominal 0dB levels between the different items.

    I would ignore the LED meter on the pre-amp and use the post gain (or single gain control if only one) to set the pre-amp output level to get correct input level into the compressor. The compressor is the item in the chain that is designed to be level-sensitive, and so you have to drive it right and set it right. With all the other items, it's a matter of working in the sweet spot by balancing the headroom before clipping against the noise floor.

    I am suspicious of the implied use of a mixer as your computer interface. How are you going into the mixer? Is the line level input simply attenuated and put through the mixer's mic pre-amps? I would seriously consider ditching the mixer for this application and getting a separate audio interface for your computer. Try to find one (e.g. RME Fireface 800) whose line-level inputs go directly to the internal ADCs without putting them through further pre-amps.
     
  5. GeckoMusic

    GeckoMusic Guest

    I say ditch the mixer, unless you need it for the headphone mix. (I think it is easier with a physical mixer than the one on the computer screen. It's a trade of work flow for a little sound quality)

    If your pre amp has an output level adjustment, then turn that down and the input gain up to get you near the -10dB operating range. That is a starting point. Try driving it lighter and harder until you get the tone you need. Always compensate for input gain by adjusting the output level in the opposite direction to keep the other devices in the chain running at nice levels.
     
  6. BudgetPro

    BudgetPro Guest

    Hi all,

    Thanks for the replies.

    My Makes and models are:

    SE2200 condensor >
    Focusrite Track master pre >
    Alesis 3630 comp >
    Multimix mixer (which doubles as a A to D).

    i know its not state of the art gear, but its good enough for what i need, a few demo tapes, myspace and a few live gigs thrown in here and there.

    I do run a headphone mix from the mixer to the performer, and i monitor on headphones although this set up isnt brilliant as once the performer is listening in i cant solo tracks without effecting their mix (i know there must be a way round this but ive only been playing with this stuff for 3 months so ive not found it yet! :shock: :D ).

    i have tried this thanks Gecko, thats how i got to where i am now. My book says to use my ears not my eyes. Thats what i did and it sounds alright. I just wanted to learn if there was a right way rather than guessing for myself.

    I assumed it would be worse to be amplifying the signal too much and then attenuating down again. It seemed like an unecessary step, maybe im wrong. What do you think?

    Ha ha! I think maybe me and my multi mix dont belong round here (hence not putting in the makes and models at the start). Ive just gogled RME Fireface 800. its nearly £1000. I havent spent that in total yet, let alone on one bit of kit!! :D Ive got MIDI to explore yet before i start upgrading!

    Cheers,
    CC[/quote]
     
  7. GeckoMusic

    GeckoMusic Guest

    Generally I like to run everything as hot as possible before distortion. If you run you input gain low, and your output level high enough to get a good signal into the next stage, then everything in the pre amp is running at a low level. (Low level = more noise from inside the pre amp) If you boost the gain, and lower the output level the preamp is running hotter (less noise) and the output is still the same. Typically the output stage is not where the noise is introduced, so having that one low enough to get a strong signal into the next device is all you need.
     
  8. Codemonkey

    Codemonkey Well-Known Member

    BudgetPro, I use a Soundblaster that was in a PC I found and Kristal which is non-commercially free.

    Believe me, no gear quality is too low for here.
     
  9. TheJackAttack

    TheJackAttack Distinguished Member

    Why are you running two compressors? The Trakmaster Pro has a compressor already and it is a "complete" channel strip. I would start by taking the Alesis 3630 out of the signal path completely. Try the following:

    Mic goes into Trakmaster Pro at an appropriate level. Initially make sure that the eq is "out" and the compressor is "out." Signal goes out the 1/4" (+4) <line out> into the multimix (I would use an input not doubling as a mic). If the multimix has a unity setting for the rotary that is your best bet. Make sure your DAW track is set at unity gain as well for diagnostic purposes. You can adjust final levels within your DAW session in post but we are just creating a baseline.

    This process should produce a clean signal for testing. Once you have a good mic level set, recorded and tested, then proceed.

    Still without the Alesis 3630, engage the onboard eq OR compressor on your channel strip. Create a new track while adjusting the threshold and make up gain, hearing how they affect everything in the subsequent signal path.

    Try this route and check back on whether you can get a recorded track.
     
  10. TheJackAttack

    TheJackAttack Distinguished Member

    After thought....make sure the make up gain is initially set at 0. This is probably what is causing the clipping in the first place.
     
  11. BudgetPro

    BudgetPro Guest

    yeah, thats a good idea, thanks jack. I bought the compressor before the pre with the intention of using it for live sound. (its dual channel for either guitar and vocals or two vocals if there was two performers).

    the trakmaster review i read on the web (cant find it now) said the comp and the eq werent much use but the pre was a bargain, being the same pre they use on their more expensive pre's, so thats why i hadnt tried the onboard comp yet.

    Having said that the 3630 does have a lot more adjustment.

    do most people comp outboard or after recording in DAW (for vox and acoustic guitar)?

    Ive tried the mic straight into the mixer but that sounded awful. Ill try without the comp next time.
     
  12. TheJackAttack

    TheJackAttack Distinguished Member

    At least start without the 3630 until you find your initial gain stage (the preamp with comp out). The outboard compressor will work on the same principals as the channel strip so once you kind of have a handle on it change your routing back. The problem is that the 3630 is also a Gate and a Limiter. Each of these serve a different function and you will need to learn these parameters one at a time. Just make sure your Trakmaster compressor is <out> when you use the 3630. Since you are already using an outboard preamp, your best bet is to bring the signal into the Multimix via a non-preamp input.

    I mainly do classical recording these days-studio and concert. I don't use any outboard whatsoever during recording. When I started out, I worked with a combination of brass bands and big bands. With guitars going through amp heads then I wanted whatever was coming out of the cabinet. If I need to compress things in post for some reason then that is where I do it-either ITB or OTB.
     

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