Mixers/Consoles DI Box or 1/4" Line

[Edrick]

So just purchased my first DI Box. Learning more about them used them a bit in the past.

My big question is from what I know they're used to convert a number of different audio types (RCA, 1/8, 1/4) to low impedance balanced XLR to come into a sound console.

If your console has enough 1/4 would it make more sense to go direct into those or does it still make sense to use a DI?

Say you have a snake that has both XLR and1/4 and you're connecting keyboards and guitars would it be better to just use 1/4 direct?

 

[chausman]

re: DI Box or 1/4" Line

I know for my current show, the keyboards/drums are giving us a very hot signal, so we are using DI's to help attenuate the signal. Also, because longer runs of XLR are easier to deal with then finding long enough runs of 1/4" cables. We also have an active DI for out bassist.

Oh, and Congrats on post 1,000.

 

[Edrick]

I know for my current show, the keyboards/drums are giving us a very hot signal, so we are using DI's to help attenuate the signal. Also, because longer runs of XLR are easier to deal with then finding long enough runs of 1/4" cables. We also have an active DI for out bassist.

Oh, and Congrats on post 1,000.

Thanks! I would of never realized I was at 1k. Definitely a lot easier to find XLR runs over 1/4. So that's one good benefit.

As far as line vs. balanced XLR what's the length limitations?

 

[museav]

re: DI Box or 1/4" Line

On the one hand, there is no reason you could not have dedicated line level inputs with 1/4" TRS jacks. On the other hand...

• Connecting an unbalanced source device would result in an unbalanced run.
• Using a DI allows you to get dual functionality from every mic channel on the mixer. With 1/4" line inputs then if you have a mixer that uses one connection for both mic and line then the associated channels pretty much become dedicated line level inputs. If you have a console that has separate line and mic inputs you could double up but would have to make sure the correct input is selected.
• There is no blocking of phantom power for mixers that use a single physical input for mic and line signals or that parallel the XLR and 1/4" TRS input connectors.
• How do you differentiate 1/4" inputs from 1/4" outputs? With XLRs you can use females for inputs and males for outputs, using a male 1/4" plug on a wall plate or in a floor box would be interesting.
• The console sees whatever impedance the source device provides and vice versa. This should not be a problem with standard microphones or line level output devices, but think of something like somebody plugging their guitar directly into the console via a 1/4" jack on stage.
• You have no isolation from the source device.

 

[bishopthomas]

re: DI Box or 1/4" Line

Also, a balanced signal can run much further distances without signal degredation and emi issues. If your source is 10-20' from the mixer just plug it in to the line inputs. You'll want to use a DI to get down the snake. Another benefit if most DI's is having a ground lift switch for those pesky buzzes from bass amps, keyboards, and similar.

 

[hemismith]

re: DI Box or 1/4" Line

Many people recommend not running mic and line level signals in the same snake. But many snakes have inputs and outputs so you're already doing that. I personally have not had a problem with it.

 

[mbenonis]

re: DI Box or 1/4" Line

Many people recommend not running mic and line level signals in the same snake. But many snakes have inputs and outputs so you're already doing that. I personally have not had a problem with it.

I suspect the reason for this is that line level signals are typically much "hotter" (i.e., higher voltage) than mic level signals. For reference, the pro line level standard of +4 dBu is approximately 1.3 Vrms, while mic level is approximately -60 dBV (or 1 mVrms). If the system is not properly impedance balanced, then the mic level inputs might see suffer from crosstalk from the line level signals. That said, if you use balanced lines, then you're good to go.

A note on Ground Lift et al. Grounding is commonly thought of as a very mysterious thing. My take on it is this. If you get buzz when you ground both ends of the XLR cable ("correctly made XLR"), then lift the ground on the receive (i.e., input or load side) of the connection, not the source side of the connection. Then, ensure that ALL pieces of equipment are grounded to one single point by way of their chasses. This can be hard to do in situations where equipment is separated by hundreds of feet--in this case, one can ground to the outlets at each end and hope there isn't much potential difference between the two (i.e., hope that there is little to no current flowing in the ground conductor).

By doing so, any currents coupled into the shield of the cable will drain into the source side's ground and not the receive side's ground, hopefully reducing the amount coupled into the system.

 

[derekleffew]

re: DI Box or 1/4" Line

Many people recommend not running mic and line level signals in the same snake. But many snakes have inputs and outputs so you're already doing that. I personally have not had a problem with it.

It's fine as long as the signals are going in opposite directions. When both LoZ and HiZ are in the same lane, the fast ones always get stuck behind the slow ones with their blinkers on.

 

[museav]

re: DI Box or 1/4" Line

It's fine as long as the signals are going in opposite directions. When both LoZ and HiZ are in the same lane, the fast ones always get stuck behind the slow ones with their blinkers on.

I'm sure you've seen the audiophile cables with the arrows showing the proper direction for the signal 'flow'. Good thing those electrons can read the arrows on the outside of the jacket and know which way they're supposed to go.

 

[cpf]

Not to mention they'd need further instruction as to when it's OK to go in reverse, since audio isn't DC...

 

[blalew]

re: DI Box or 1/4" Line

As far as line vs. balanced XLR what's the length limitations?

My rule of thumb is no unbalanced run longer than 25'. If you can keep it at 10', all the better.

As an aside - 1/4 unbalanced outputs can mean just a line-level source (keyboard, CD player), or it can mean a high impedance (instrument) source of any level... The DI takes care of either one.

The instrument/hiZ source requires a higher (typically 10x) input impedance so that it isn't loaded appreciably.

Another rule of thumb I use is passive DIs for line level devices & active for instruments. active DIs typically have a higher input impedance & serve passive bass guitars better... As any rule of thumb, there are exceptions.

 

[Edrick]

So for studio recordings is it common to have many DI boxes?

 

[Footer]

So for studio recordings is it common to have many DI boxes?

Depends. For a keyboard, yes. However,most people want the sound of the instrument in its natural form. So, most mic the instrument or the amp.

Sent from my Galaxy Nexus using Tapatalk

 

[tk2k]

So for studio recordings is it common to have many DI boxes?

I don't know why this hasn't been hammered out already by all posters.

The only reason to ever keep a signal as unbalanced is if it is headed directly to an amp less than the shortest distance possible, under 15'

An unbalanced signal is much more susceptive to interference, and over the length of the cable the actual tone and sound will change. Since guitars have existed for so long this is actually a plus according to some professional guitarists, but in anything else it's a really bad thing. In the case of a guitar, making a 50' run to your board will change the sound, and the guitarist (if he's got any ears) won't like how it sounds. This is why people usually mic a guitar amp directly.
Side note: in pro settings most guitars are wirelessly connected, and then out of the wireless reciever go through a re-amper before heading to the guitar amp, This actually unbalances the signal and reproduces the same sort of signal coming out of a guitar directly. There was a good article on it in LSI two moths ago and should still be online.

Lastly, isolation is important. Guitars and guitar amps sometimes explode, signals get crossed, a jack is ripped out and happens to hit the wrong thing, and **** can explode. A DI will usually protect your board from this sort of thing, which can blow out a channel, or if it's powerful enough, travel through your signal chain and kill your mains and monitors.

Studios will often use extremely high end hardware to capture the 'true' sound of a guitar signal. It's not really accurite to call this gear a DI box, but it does the same thing, it takes an unbalanced signal and transforms it into a balanced or digital signal for the engineer to make use of.
hope this helps

 

[Edrick]

I ended up purchasing two Whirlwind Directors and a Whirlwind pcDI.

 

[bishopthomas]

Those are very decent DI's. They do exactly what they are supposed to. I like Radial myself. I'm a dealer so I get cost, plus they are indestructible. You could split a coconut with those and an ice skate.

 

[mbenonis]

You know, I wonder why guitars are not balanced outputs to begin with. I don't see any reason, other than tradition, that the pickup couldn't be wired in a balanced fashion with a safety ground via the shield of a shielded balanced mic cable.

 

[DuckJordan]

Space and cost of components. Pickups are essentially magnets. You have to fit several tiny magnets + wiring inside a 1/2" by 2" section one right next to the other. Then you have to get a circuit board in there to change the magnetic signal to something we can read as a guitar. Then it has to be sent out. To create a balanced board would at at least 30 cents to each circuit board add a little extra weight and change out cables as well as how the amplifiers pickup the signal coming from the guitar... You can't really go directly from guitar to sound board can you?

 

[Kenien]

Those are very decent DI's. They do exactly what they are supposed to. I like Radial myself. I'm a dealer so I get cost, plus they are indestructible. You could split a coconut with those and an ice skate.

I started work at Long Island University (Brooklyn) this year, and made them get two stereo DI's. These things should be illegal, since brass knuckles are.

 

[Edrick]

A few years back we connected right to a sound console from a guitar, didn't cause any issues hmm