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Isn't the FOH just a mixer (why need a DI)?

Discussion in 'Effects [BG]' started by kokoshmusun, May 19, 2011.


  1. kokoshmusun

    kokoshmusun

    Feb 5, 2011
    I'm confused about something: Isn't what you guys call front of house (FOH) after all a mixer? Don't all mixers have both line-in jacks and XLRs? Thus, what does the XLR output on my D.I. box (MXR M80) add to my rig that it's line out doesn't have?

    In other words, I've been seeing some bass "preamps" around that don't have the XLR output (the D.I. function) but have just the line-out. I'm interested in a couple of them (EWS Tri-logic and Zeibek Submarine). And if I got one of them, can't I just let go of my MXR M80 (which I love, but wouldn't need anymore if I use the new preamp I get)????

    Can't the FOH guy just take the line-out from my "preamp" (e.g., EWS) and do whatever he needs to do?
     
  2. Phalex

    Phalex Semper Gumby Supporting Member

    Oct 3, 2006
    G.R. MI
    He can but depending on what sort of tone shaping you're doing with your preamp, he may not like the signal you're sending him at all.

    The way I figure it is playing bass / keeping time are my responsibilities. Making that sound freaking awesome out front is the sound guys responsibility. I send the sound guy a completely dry uncolored signal form my bass. He tweaks it to make it sound great in any given room. What sounds great onstage (All that I can hear when I'm playing) may sound like total dog poo coming out of the massive system out front.
     
  3. prd004

    prd004

    Dec 3, 2010
    Most mixers take mic-level and line level signals. The high-impedance output on your bass needs to be converted. The DI has a trasformer to convert high impedance signals to mic level.

    I don't know about the line out on the preamps you mention, but my educated guess would be they are designed for "front of Amp" use, thus the line out will be high impedance as well.
    Read your manual, if it's a true line-level output then yes, you could plug it straight in to the board
     
  4. Altitude

    Altitude An ounce of perception, a pound of obscure. Supporting Member

    Mar 9, 2005
    Denver, nee Austin
    The XLR balanced signal maintains itself better over long cable distances than a high-level instrument output. And, a lot of live sound hardware (microphones namely) use XLR natively anyway. So it makes more sense to use that for the connections to the soundboard.

    EDIT: If a mixer has high level inputs, as most do, there's nothing bad about using those for short distance runs.
     
  5. MNAirHead

    MNAirHead Supporting Member

    the conventional answer is that it depends on how far away you are from the board.

    OVERALL, I'd hang on to the M80.. it's a rugged and dependable DI...

    IF close to the board (less than 20 feet) you really don't need a DI for most applications.
     
  6. The problem is that your line isn't balanced and unbalanced signals have a tendency to pick up noise, especially if the FOH mixer is 50' or more away from the stage.

    If there's more, someone else chime in.
     
  7. Eublet

    Eublet

    Jul 28, 2006
    Noise...balanced signals prevent noise from entering the signal much better, especially as the distance grows.
     
  8. kokoshmusun

    kokoshmusun

    Feb 5, 2011
    Ok, that's a lot of help already, thanks. Why I wanna experiment with these preamps is they are smaller size, and I haven't really been able to warm up to the distortion channel on the MXR (maybe I just don't like any distortion on bass, I don't know since I haven't tried other distortion boxes). So I wanted to separate the preamp from the distortion, and maybe get a dedicated distortion later on.

    But I don't wanna carry two preamps (MXR and EWS). So I guess, while I can still experiment with EWS and similar, I will keep MXR on my board because of the XLR.
     
  9. Handyman

    Handyman

    Sep 4, 2007
    Austin, TX
    That's pretty much it. The differential signals you get with an XLR output are VERY resistant to noise. Or, to be more accurate, the preamp in the mixing board cancels out the common mode noise picked up in the long cabling run.

    With plain old single ended instrument cable, any noise picked up by the long cabling run will make its way into the final mix.

    If you want to feed the mixer a post pre-amp signal, you could always feed the line out of the pre-amp into a relatively small passive DI box.
     
  10. SteveC

    SteveC Moderator Staff Member

    Nov 12, 2004
    North Dakota
    So many threads could be deleted and so much money could be saved if we all had this attitude.
     
  11. kokoshmusun

    kokoshmusun

    Feb 5, 2011
    And I think these passive DI boxes you're talking about are standard in even crappy venues. When I used to play around in NYC bars, I saw many of these (if I'm not mistaken). So, assuming the venue would already have this, I could just bring my preamp, and if the cable runs long, ask to go into the passive DI box first. Is my reasoning correct?
     
  12. A DI does four things.

    It converts from a high impedance signal to a low impedance signal, so that you can run a long distance of cable without worrying about the effects of parasitic capacitance adding up.

    It converts from an unbalanced signal to a balanced signal. This helps to keep things quiet.

    It converts from 1/4" to XLR. While most mixers do have both 1/4" and XLR inputs, most stage snakes (To my knowledge.) have only XLR inputs running to the console, and the handful of 1/4" connections are usually used for monitors, or unpowered mains.

    It also converts from instrument, line or speaker level, depending on what you have plugged in, to mic level.
     
  13. Eublet

    Eublet

    Jul 28, 2006
    That only works when the dry, uncolored sound of your bass is already in the general ball park of the sound you are going for with the band and the songs you are playing. Add in FX/overdrive/etc, and then that approach no longer applies. Guitarists don't send clean, uncolored signals to the sound guy, and it's not his responsibility to make their guitars sound right. The sound guys job is to mix what the band gives him. If a bass part requires coloration, it's the bass players job to provide it, and the sound guys job to mix it with the rest of the instruments.

    The reason bass is complicated is because of the energy in those low frequencies, and the way they respond acoustically in different venues. There's also a huge misunderstanding about amplifying bass completely. Having a one-size-fits-all approach to getting a bass tone amplified through a PA is IMHO a huge problem in it's own right.
     
  14. MNAirHead

    MNAirHead Supporting Member

    MxR distortion is NOT a good evaualtion.....

    Out of my 20 boxes, it is my favorite one (for value and durabiltiy).. the tone shaping is way above average.

    That being said, the distortion is silly.. really meant to be used in small doses.
     
  15. MNAirHead

    MNAirHead Supporting Member

    OVERALL...
    Your MXR will do 90% of what folks on here banter about... it's by far one of the most durable tone shapers out there.... the phantom buffer is well worth having in your signal chain.
     
  16. rockstarbassist

    rockstarbassist Banned

    Apr 30, 2002
    The Woodlands, TX
    Endorsing Artist: HCAF
    So many threads could be deleted and so much money could be saved if we all had this attitude.
     
  17. Yeah, everywhere I play the sound guy has one and just uses it as a matter of course with every bass player, unless they have an alternative. Go for it and maybe even buy your own to use in an emergency. it'll just sit on top of your rig or in your gig bag, no board space needed.
     
  18. Some DIs contain a transformer and a ground-lift switch, which allows breaking hum-inducing ground loops.
     
  19. Eublet

    Eublet

    Jul 28, 2006
    I should add that bass players are also a large part of the problem when it comes to having their signal amplified through a PA. All that bass boost that is often applied to get a thick tone on stage is not needed at all through a good PA that has good subs. It makes the sound guy's job very difficult to say the least. I think that's why there seems to be this undeclared war between sound engineers and bass players. Sending a pre-EQ signal to the FOH is a good idea generally speaking I think. That way he can shape the tone as necessary to make it fit from the FOH perspective. But suggesting you have to send a clean signal to the FOH is a bit much. If you're using heavy FX on your signal, then it's a good idea to send a clean signal and a wet signal so that the engineer can mix the two to get the overall tone as long as he isn't lazy.

    I think mic'ing your cab is the easiest way to get your tone to the FOH. It's doubtful the stage tone coming from a bass rig is too deep for the FOH to amplify properly, but boosting low end can be largely hidden in a bass rig, but send that boost through the DI and amplify it through the house subs and all the sudden it's a nearly unusable tone.
     
  20. rockstarbassist

    rockstarbassist Banned

    Apr 30, 2002
    The Woodlands, TX
    Endorsing Artist: HCAF
    Yep. There has to be compromise. I play clean/wet about a 60/40 mix during our set. If the sound guys would LET me run two signals, I would. I do not boost uber-low freq's like most noobs so it's really not that hard to mic and get the grind and attack I get from my cabs. So if you only get 1 signal, miking is just simplest.

    I liken it to the referee-complex. You're there to make sure things go right- not be the center/focus or a determining factor. Some dudes just can't help themselves, however.

    Also, it's funny those kind of "just run clean into a DI" comments are found in the Effects forum. Well, maybe not as funny as it is sad or :facepalm:-worthy.

    troll-face-meme.
     

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