Direct box woes

scelerat

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3,185
My bass rig is a '70s Music Man HD 130 through a single 15" reflex horn cab.

It seems that nearly every time I encounter a sound man who wants to use a DI to capture the bass sound, there's a problem. Typically, the signal path the sound guy wants to use is guitar > DI > (amp / sound system). Problems include weird feedback, distortion, and periodic signal loss.

My most recent encounter with a DI included a sound man who was noticeably agitated by the absence of a balanced/XLR preamp out, and kept trying to put the DI between the amp and my speaker cab. When I asked him to stop, he growled something about not spending four years in sound engineer school to be told how to use a DI. Are there DIs that take a speaker load from the amp like this? I didn't think so, so I told him I was happy to play with stage volume only (in a room with standing capacity of maybe 100), or simply with a mic'ed cab (which always sounds fine imo), but he didn't want the sound in "his room" to "sound like ****."

Well it sounded like **** anyway; my bass would keep getting quieter and quieter through the set until it was totally gone, then it would come back quickly but gradually (ie. not simply on/off, but 0-10 in about 5 s). I went home thinking something was wrong with the power tubes, until the next practice and I did some controlled tests, and it occurred to me that it was another instance of weird DI behavior.

I'm torn between just saying "no" to the DI, period, and insisting on a mic, or figuring out the right way. It's like there are a lot of sound guys out there who have never seen a bass amp with no preamp out or XLR (this guy wasn't the first).

I *think* the "right way" for my amp is:

- guitar > amp input 1
- amp input 2 > DI

This way my amp gets the full signal from my guitar, no shenanigans. This works for multi-amp setups, I don't know why it wouldn't work for sending a signal to a direct box. What do you all think?
 

scelerat

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3,185
If you are using a regular DI you should not be connecting it in the way you are suggesting to.
Yet every* time someone has used a DI with my rig -- guitar > DI > amp -- it's messed up the sound something fierce.

Why would using the output from the second input not be the right way? It would give the sound guy the signal from the amp he wants, and it would keep his junk out of my signal chain.

This is likely what he wanted to use: http://www.radialeng.com/jdx48.php
I'm sure there are DIs like this one, but that definitely wasn't the model he was using in the instance I'm referring to. It had two 1/4" jacks and one XLR, no apparent switches; a pretty simply box. Before he was trying to plug the head into it from the speaker outs, he was trying to find the preamp out.

* ok, nine out of ten times
 

scelerat

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3,185
Oh wow, forum turns "s h i t" into four stars. Like the IMDB rating of the last G-rated movie I watched.
 

bender

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1,166
Yet every* time someone has used a DI with my rig -- guitar > DI > amp -- it's messed up the sound something fierce.

Why would using the output from the second input not be the right way? It would give the sound guy the signal from the amp he wants, and it would keep his junk out of my signal chain.
I may be totally misunderstanding what you are saying (and therefore apologies), but if your Music Man is anything like my Music Man, none of the inputs on the front panel acts as an output (this is where I am confused by what you're saying).

Manuals for the new ones are available here, and they pretty much mimic the controls/inputs/outputs my vintage one has: http://www.music-man.com/images/amps/212hd130.pdf

Guitar --> DI Box ---> amp input/ PA [which is what you posted is a problem]

I can't see the other way working at all off a second input. It's an input not an output.

So, what I am thinking is that the DI that the sound guys use screws around with your input signal. Thus I think another solution is to run an ABY switcher of some sort like: http://www.radialeng.com/bigshotaby.php

You run a line to the ABY switcher, have it in Y mode and send one signal as you would normally to your pedals/amp and the other to a DI box and to a PA


Regards

-- Bender
 

78deluxe

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5,355
Yet every* time someone has used a DI with my rig -- guitar > DI > amp -- it's messed up the sound something fierce.

Why would using the output from the second input not be the right way? It would give the sound guy the signal from the amp he wants, and it would keep his junk out of my signal chain.



I'm sure there are DIs like this one, but that definitely wasn't the model he was using in the instance I'm referring to. It had two 1/4" jacks and one XLR, no apparent switches; a pretty simply box. Before he was trying to plug the head into it from the speaker outs, he was trying to find the preamp out.

* ok, nine out of ten times
I'm not sure what you mean by second input (being used as an output)?

What amp head are you using?
 

scelerat

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3,185
I may be totally misunderstanding what you are saying (and therefore apologies), but if your Music Man is anything like my Music Man, none of the inputs on the front panel acts as an output (this is where I am confused by what you're saying).
I guess "pass through" is a more appropriate term.

The inputs are labeled "1" and "2". If I plug a guitar into Input 1, then take a cable from Input 2 and plug it into a second amplifier, the second amp gets the signal from the guitar as if the guitar was plugged in directly. I'm not talking about the separate channels, just the two inputs on either channel (Normal or Bass). This is how most vintage Fenders and Marshalls work, too. On my MM, the guitar signal gets passed through regardless of whether the first amp is in standby (and possibly, whether it's on or not -- hmm never tried that).

My theory is that i'd have better luck with DIs in these situations if I ran a cable from Input 2 into the sound guy's DI and don't bother with running the DI back into my amp.

Pic of a music man HD-130 front panel with two inputs on the normal channel:

 
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scelerat

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3,185
Although I certainly don't balk at the opportunity to acquire more gear (as in, a reliable DI), I kind of like how simple my setup is right now. Most places I play don't really need to DI the bass (it's plenty loud for most rooms) and/or mic it.
 

bender

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1,166
I guess "pass through" is a more appropriate term.

The inputs are labeled "1" and "2". If I plug a guitar into Input 1, then take a cable from Input 2 and plug it into a second amplifier, the second amp gets the signal from the guitar as if the guitar was plugged in directly. I'm not talking about the separate channels, just the two inputs on either channel (Normal or Bass). This is how most vintage Fenders and Marshalls work, too. On my MM, the guitar signal gets passed through regardless of whether the first amp is in standby (and possibly, whether it's on or not -- hmm never tried that).

My theory is that i'd have better luck with DIs in these situations if I ran a cable from Input 2 into the sound guy's DI and don't bother with running the DI back into my amp.

Pic of a music man front panel with two inputs on the normal channel:


Right, I have a Marshall 2061x that behaves like this--but did not know this can be done on a Music Man (I have one). What one does on the Marshall is bridge to the other preamp section, and so after doing some digging, and this thread turns up--so it should work on mine (and here I thought you were crazy lol): http://www.pacair.com/discus/messages/14/2281.html?1324859485

Will it work, however, without bridging back into the amp? I've never tried this with any of my amps.

However, this may not solve your problems. I suggest you test it out in a friendly shop--take your amp and bass in, and fool around with a decent DI into a PA. I really don't think you can tell until you do this.
 

scelerat

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3,185
Will it work, however, without bridging back into the amp? I've never tried this with any of my amps.
Sure it does, this is one way to run multiple amps, and that's why the channel bridging works (though in old Fenders I think the two channels are out of phase and you get weird comb effects).
 

riffmeister

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16,617
Typically, the signal path the sound guy wants to use is guitar > DI > (amp / sound system). Problems include weird feedback, distortion, and periodic signal loss.
The feedback/distortion/signal loss are at your amp or at the PA?

Either way, this is bizarre, never heard of this happening before. Using a DI box is a no-brainer, in my experience.
 

scelerat

Member
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3,185
The feedback/distortion/signal loss are at your amp or at the PA?

Either way, this is bizarre, never heard of this happening before. Using a DI box is a no-brainer, in my experience.
The weirdness definitely happens at the amp. This last time, there was nothing coming out of my cab for a while, then it cycled back in. In and out several times throughout the set.

Other times there has been squealing feedback, similar to what happens if you try to use an unshielded speaker cable as an instrument cable (and maybe that's exactly what was going on in those instances).

I don't know why -- maybe i've just had incredibly bad luck.

Tangentially, on a purely subjective level, I find that many of the venues that have big expensive sound systems try to make rock and roll rhythm sections sound like an EDM ravestravaganza. Crazy heavy kick drum, ice-picky snare, boomy, nauseating bass.
 
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soulsonic

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980
Most DI boxes actually are designed to plug between the amp and speakers. That's completely normal. The speaker out goes to the input of the DI, then the speaker thru goes on to the speakers, and the XLR goes out to the PA. The circuit that taps the DI signal off from the speaker out is a much higher Z than the speaker, so the amp acts like nothing has been added there, just sends 99.999% of its juice to the speaker and a tiny .001% of it to the DI circuit. If it was plugged in this way and you had all kinds of weird problems with levels, then the DI box was probably broken or something. Do as others have suggested and get yourself a good DI box that you know will work well and just leave it permanently hooked up.

DI boxes don't work with instrument-level signals...totally screws it up and at best will make you sound bad. The majority of them (especially the passive ones) are ONLY designed to work with speaker level signals. Some of them also work with line level, though if you have an XLR out, there is no reason at all to jam a DI box in series with it unless maybe you have some horrible ground loop hum problem...and even if that is the case, a different kind of isolating transformer would be more appropriate.
 

riffmeister

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16,617
The weirdness definitely happens at the amp. This last time, there was nothing coming out of my cab for a while, then it cycled back in. In and out several times throughout the set.

Other times there has been squealing feedback, similar to what happens if you try to use an unshielded speaker cable as an instrument cable (and maybe that's exactly what was going on in those instances).
An inexpensive unit like the Whirlwind Imp 2 (about fifty bucks) and three known good cables (two 1/4 inch instrument cables, one XLR cable) should solve your problems. Unless, of course, the sound guy is drunk or something..... :)
 

scelerat

Member
Messages
3,185
Most DI boxes actually are designed to plug between the amp and speakers. That's completely normal. The speaker out goes to the input of the DI, then the speaker thru goes on to the speakers, and the XLR goes out to the PA. The circuit that taps the DI signal off from the speaker out is a much higher Z than the speaker, so the amp acts like nothing has been added there, just sends 99.999% of its juice to the speaker and a tiny .001% of it to the DI circuit. If it was plugged in this way and you had all kinds of weird problems with levels, then the DI box was probably broken or something. Do as others have suggested and get yourself a good DI box that you know will work well and just leave it permanently hooked up.
I swear every other time there's been a DI involved, the sound guy wants me to plug the guitar directly into the DI, then a 1/4" cable goes to the amp input and an XLR goes to the sound system.
 

riffmeister

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16,617
I swear every other time there's been a DI involved, the sound guy wants me to plug the guitar directly into the DI, then a 1/4" cable goes out to the amp and an XLR goes to the sound system.
Very common. There are DI boxes that work that way and DI boxes that go between your amp and cab.
 

soulsonic

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980
Even if it's a DI that has a Hi-Z instrument level input, if it's patched before you even get to the amp, you won't be getting any of the sound and tone of that amp in the signal going to the board. That would sound awful in most cases, even with bass.
And if it's a passive DI, it will totally wreck your sound if you patch it before the amp without a buffer or preamp preceding it. Ultimate tone-suck. There are some active ones that include buffering and can be OK with a low level instrument signal, but still...really will give a better representation of your sound if the signal is taken from the speaker out.
 

Injured_Ear

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Messages
34
I have almost never had issues with a passive DI between the axe and the amp. Not always the best tone, but always usable and eq'able. Often when taking a preamp out into a DI (whether it's an XLR out of the head or just a line out) it's usually EQ'ed to make up for weaknesses in the bass rig or just too much bottom end.
The ONE instance I ever had problems was when a bass player had active pickups and was thumping and slapping so hard that he overloaded the transformer in the Whirlwind Director DI I was using at the time. In that case I took an XLR feed from his amp.

That said, I'd put a 57 up and mic the bass cab any day of the week if that's what I needed to get a clean feed into the PA system.
 






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