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  1. Member
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    I've noticed something rather troubling about recording into my Panasonic DVC80:

    For the purpose of recording a demo video, there is a guitarist playing with a midi sequencer. He uses an Alesis mixer, and a Bluetube, and Roland SD-35 midi player.

    I am taking the main out from the mixer, going into a direct box, and then out to the XLR input of the camera.

    The midi sequencer records beautifully into the camera. The problem is the guitar, but not always - what I mean is that when he plays single note solo type music, it records fine. But when he plays a lot of chords, it comes into the camera distorted. I checked of course the levels and made sure it wasn't clipping. I even lowered the main volume and it still does it.. Does anyone know why this is happening?

    I can post some mp3 clips if you want to hear it...

    Thanks,
    Mike
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  2. Член BJ_M's Avatar
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    sounds like a preamp is being saturated

    check that the bluetube is set on inst and not mic , use it's -20db pad

    make sure phantom is off ..

    try reversing the channels (one tube might be wacked)

    check the tubes ..

    try going from the bluetube direct to the directbox to the tape also ..

    that preamp has 30db i think of tube drive plus 30 or 40 db of gain possable.

    it also has +4 or -10 selection , so match this to your mixer input ..


    make sure the power supply on the preamp is puting out 18volts also --


    also make sure you are running a proper balanced connection from the preamp to mixer and no ground loops (lift one side ground -doesnt sound like thats the problem though) and use balanced in.. or make sure both sides are unbalanced - dont mix unless you know how to make an adaptor ..
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    We're using the older model of the bluetube:
    http://presonus.com/bluetube.html

    The setting we had at the time of recording were as follows:

    PAD button was pushed in, other two buttons (for that channel) were not pushed in.
    Drive was set at 0
    Gain knob was turned to about 11 o'clock

    On the Camera (panasonic DVC80):
    XLR input was set to MIC level
    Input adustment knobs were set so that the incoming signal would not clip (as close to 0db as possible (around 10 o'clock))

    Direct Box is a Rolls Matchbox DB25
    Attenuator set to 0dB
    Ground/Lift switch set to Gnd

    Does this help narrow the problem down?

    Thanks,
    Mike
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    Here's two clips I made into mp3s from the shoot:

    The first one, he is playing single notes, and the audio is clear
    The second one, he is playing chords on the guitar, and you can hear the distortion in it

    clip 1

    clip 2
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  5. Член BJ_M's Avatar
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    On the Camera (panasonic DVC80):
    XLR input was set to MIC level

    the level coming out of the mixer is line level is the problem i would think .. you are overdriving the mic preamp in the camera (which is very easy to do), make sure auto gain in camera is off (if that model has it).

    i'm not postive that input on the DVC80 is true balanced also -- it might be only quasibalanced


    also (not related) , i would use the lift on the direct box ..

    nice preamp btw ...
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    Yeah it's a great preamp, he has the newer bluetube dp sitting in the box on the shelf, we're thinking about trying out that one - the guitarist endorses Presonus, so they send him this stuff to use, but anyways, I really don't even understand what the direct box is for, I was just told to use it - what is the ground/lift switch?

    So you think it is the volume control of the channel that the guitar is on that is causing the problem? To me that seems odd, because if I lower THAT volume, it will make the guitar quieter and won't blend well with the midi sequencer as the sequencer will just be too loud and I'll lose the mix..
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  7. Член BJ_M's Avatar
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    btw - i realize that was only a mp3 , but it didn't sizzle for me (the track) ...

    i could not help myself -- i touched it up it a bit ...

    untitled.mp3
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    wow! what did you do??? that sounds great !
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    Originally Posted by sdsumike619
    Yeah it's a great preamp, he has the newer bluetube dp sitting in the box on the shelf, we're thinking about trying out that one - the guitarist endorses Presonus, so they send him this stuff to use, but anyways, I really don't even understand what the direct box is for, I was just told to use it - what is the ground/lift switch?

    So you think it is the volume control of the channel that the guitar is on that is causing the problem? To me that seems odd, because if I lower THAT volume, it will make the guitar quieter and won't blend well with the midi sequencer as the sequencer will just be too loud and I'll lose the mix..
    no i think it is because your camcorder is on mic ... though a direct box can knock the signal down to mic ...but the mic preamps in prosumer cams are not all that beefy
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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  10. Член BJ_M's Avatar
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    the ground lift switch is to prevent ground loops (hum)

    and further to above - you output on the direct box is 0 gain - which (assuming you are sending line level) means that you are sending line level to the DV tape ..
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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  11. Член BJ_M's Avatar
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    Originally Posted by sdsumike619
    wow! what did you do??? that sounds great !

    i ran through my studio set up real quick -- i do this kind of work kinda a lot ..
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    I can tell! what is your "studio" setup? whatever you did to it sounds really good! All this stuff is starting to drive me up the wall with ground lifts, hums, loops, line levels, mic levels, gains, db, etc...

    Is there a bottom line to how I can record the guitar and sequencer at the same time and have a good blend between the two while keeping the guitar signal clean, but not weak?
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    i would record each to their own track myself .. then play around with mixing them later when the pressure of recording is off .. specially since the stringish sound is the weak link at the moment ..

    DV records PCM 48khz - thats good -- but i dont know how good the op-amps and such are in the dv cam audio wise ...


    here is a basic guide on mastering ... http://www.looperman.com/tutorials_production_master_the_situation.php
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    i was just talkign to the guitarist.
    He said that the bluetube preamp is necessary in order to boost the signal coming from the guitar.

    He then asked me to ask you if there is a way to convert the guitar signal to line level before going into the camera so that it isn't so hot and doesn't overload the camera like it's doing now... Is that what the direct box is for? Or is that something different? I'm going to read that article now that you posted..
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    about recording each to a different channel on the tape:

    It seems like I tried doing this before, but when I went to capture the footage via firewire, it only captured one side. For capturing, I don't use the DVC80, I use a Canon ZR-20 that I have so as not to have unnecessary use on the heads of the Panasonic...

    Should also mention that the Alesis mixer we're using is the MultiMix 6FX:
    http://www.alesis.com/products/multimix6fx/index.html which has the built in effects..
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  16. Член BJ_M's Avatar
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    i dont think you quite followed my drift on the set up ...

    you should do:
    guitar -> bluetube (hi impedance connection) -> mixer (line level in/out) -> direct box (line level in/out) -> dv tape (line level in)
    i.e. unity gain throughout system from preamp to dv....

    what you have now:
    guitar -> bluetube (hi impedance connection) -> mixer (line level in/out) -> direct box (line level in/out) -> dv tape (mic level in)


    avoid the effects on the mixer board during recording - they really dont sound that good .. you can use some eq and high pass and compression on guitar .. but keep it very very little .. dry for the synth (maybe roll off the highs a bit i would judge) ..

    once set up -- leave levels alone and try for max. levels at about -3db (peaks) on your meters .. or so the yellow is just flickering but never red
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    You know what happened one night when I went to record this similar type of thing was that the channel was set to line level (like you're suggesting I do now) and EVERYTHING came into the camera overloaded and distorted...I'm sure I must have missed something at that time..

    Do you use Vegas? If I do record the sequencer and guitar to separate channels on the tape, when I capture the footage, it gives me one video stream and one audio stream - the audio stream, I assume, will have my two channels (left and right) so in order to separate them, would I just duplicate the audio track and then right click on the event and pick channels -> left only, and the other to right only? That's the only way I could think of how to get the two channels separated.

    The only effect that he uses is reverb, which is built into the mixer (which is why he likes that mixer) doesn't make sense to not use it,,, plus if we don't use it, it will be harder for him to play because he's used to the sound of playing live...
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    re: reverb ... i can see that , but ussually you would do it only for the monitor mix back to him .. but non the less ..


    yes i use Vegas -- you know you could just buy a 8 or 16 channel input for Vegas as vegas can record up to at least 12- 24 audio tracks at once (more if you have the system) .. it is real good for that and was used that way to record a S. Crow llve gig (including 2 cams) that went right out to dvd after being mixed and edited in Vegas on a plane .. or you could record even straight into vegas with a standard decent sound card like a m-audio ..

    that is how you seperate a stereo track - yes ..
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    ahh interesting ideas, but we're not exactly running a big studio here..
    Some stuff that might help about the situation,

    My camera specs are as follows:

    INPUT 1, INPUT 2
    XLR (3 pins) a2 (CH1, CH2)
    LINE/MIC switching, high impedance
    LINE : 0 dBu
    MIC : –50 dBu/–60 dBu (menu selection)

    Correct me if I'm wrong, but it seems the only reason for the direct box is to convert the unbalanced signal coming from the mixer, to a balanced signal for the camera.

    If this is the case, and I opt for splitting the sequencer and guitar into separate channels, I would need two direct boxes (one for each component) and the inputs on the camera should be set to LINE - then I would be able to adjust the incoming volume of the guitar using the channel control knob ON the camera.

    Does that about solve it you think?
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    doesnt the mixer have balanced out ?

    at the mixer you can mix left and right busses , each with thier own instrument -- you dont need two direct boxs (maybe not any) .. but you can do it as you suggest also , should work fine ..
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    yes you're correct, the alesis mixer has balanced 1/4" main and monitor outs.

    I don't really understand what you mean by "at the mixer you can mix left and right busses, each with their own instrument"

    on this mixer MultiMix 6FX, I would have to have the guitar panned left 100% and the midi player panned right 100% and have the left out go to one channel in the camera, and the other to the other channel in the camera, yes?
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    yes -- right , or use the aux busses is what i meant , and send each input to a different buss .

    aux 1 to left in on dv and aux 2 into right as an example .

    nothing would be conected to the main out .. for recording anyway ..
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    I don't know if this simple mixer has aux busses on it.. Enough of this for one day haha - Question though - how on earth do you get any work of your own done while helping us lost souls all day long? I have to get this demo DVD done so I'm just going to salvage what I can from this shoot... But before the next shoot, I'm going to try what you said and go from there, thanks for your help
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    probably should have asked this sooner, but is it even possible to correct the distorted guitar sound in Vegas that is heard in clip 2 that I posted? I doubt it since that's how it was recorded, but maybe?
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    somewhat -- soundforge would be better

    distortion is distortion though -- you can not remove it if it is already there - you can smooth out the waveforms and cut out the clipping that i hear there now and then ..
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    what is smoothing out the waveform? there's no clipping in this file, doesn't seem to go about -4.2, but yes, the distorted guitar is there, how do I do that smoothing thing and will it help the distortion at all?
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    try it and see - i think you can do it in vegas also -- it is one of the filters
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    I tried it, seems to just muffle the sound, that wont' work =(
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    no - i wasnt really sure -- removing distortion is pretty difficult after the fact ..

    sony has some very expensive oxford plugins for pro-tools ...

    also sony noise reduction might help (or direct-x plug in called x-crackle) http://www.waves.com/content.asp?id=142

    do a search for dx or vst plug in's that might help .. many are free
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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    come to think of it ... x-crackle restoration bundle is only for protools also i think ...
    "Each problem that I solved became a rule which served afterwards to solve other problems." - Rene Descartes (1596-1650)
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