How do you use a DI Box?

[darkecho]

Ok, I heard a buddy talking about Re-amping and I wanted to use it to get a better feel for how mic placement affects the sound, So I got a DI box so that I could plug my guitar into my computer and record the undistorted guitar signal, then I was going to send that signal back out into a guitar amp and then Mic the amp while moving the mic around and listening to the looping guitar part to see how it was affected.

So I bought this 40$ DI box and get home, plug the guitar in, and when I record, the signal looks super weak, like Barely showing up on the track. (this was Guitar>DI>Delta44>PC)

then I plugged the guitar directly into my delta, (Guitar-Delta-PC) and I got the same quality/loudness of the signal... this would make me assume that my DI box isnt doing anything...

whats the deal here? I did find that when I used my preamp in the series (Guitar-DI-Preamp-Delta-PC) that the signal got boosted. I forget if the phantom powere affected it at all... are you SUpposed to use a preamp with a DI box? I was under the impression that you just used the DI box to boost the signal....

what Do i need to do in order to be able to Re-amp???? Thanks!

 

[ermghoti]

A DI is not a preamp, it converts the signal from instrument to line resistance specs. Yours is behaving properly, use it with a pre. You will need a reamp box, which is the opposite of a DI, for best results with the final, amplified sound.

 

[darkecho]

so, should I return my DI and get a Reamp box instead? or do I need both? Thanks!

 

[boingoman]

Guitars don't work well just plugged into passive DIs, I am assuming you have a passive DI?

If you are just wanting to play with mic placement, you can probably just run an unbalanced line out from your Delta to the amp, no fancy boxes needed. An active DI or line out from your guitar amp should give you a decent direct recording to work with. If the Delta doesn't support unbalanced output, you can try using the DI backwards with a 1/4"-XLR cable to feed your amp.

Reamping is only complex if you want it to be, or need it to be. For the average home guy, it doesn't need to be, a lot of times.

 

[darkecho]

Well I want to reamp for two reasons, one, to get a better understanding of how mic placement affects sound, and two, to actually use Re-amping as a tool to adjust the Amps settings to get the best tone.

so I would like to be able to record takes of a guitarist until he gets it perfect, then reamp that perfect take to get the "perfect" tone for the guitar part. and also to get the perfect mic placement for the part. all while having it sound just like he was plugged right into the amp.

what should I get to accomplish this?

 

[darkecho]

the Delta 44’s breakout box handles four balanced/unbalanced, +4dBu or -10dBV signal level analog inputs and outputs, and yes its a passive DI box.

 

[boingoman]

Well I want to reamp for two reasons, one, to get a better understanding of how mic placement affects sound, and two, to actually use Re-amping as a tool to adjust the Amps settings to get the best tone.

so I would like to be able to record takes of a guitarist until he gets it perfect, then reamp that perfect take to get the "perfect" tone for the guitar part. and also to get the perfect mic placement for the part. all while having it sound just like he was plugged right into the amp.

what should I get to accomplish this?

A DI or guitar preamp that gives you a decent direct signal is the first step.

As far as going to the amp, like I said, many times a cable is all you need. People plug drum machines and keyboards into guitar amps all the time, which is basically reamping. No fancy boxes needed.

If you are going from a balanced output to your guitar amp, you will need to convert to an unbalanced signal. You may be able to use a DI backwards. The biggest problem with this is that running backwards through a DI boosts the signal level, and you may not be able to keep it low enough that it doesn't overdrive the amp inputs. Running such a low signal level may raise the noise level too much, as well. If it works, great. If not, then a reamping box is probably your best bet, like the Radial X-amp.

 

[darkecho]

so is a passive DI not a good choice to initially get that good direct signal?

I want to be able to have the guitarist come over, record his track till he takes it perfectly, and then have him leave and me be able to mess with it to my hearts content to get it how I want it, and also to be able to pull it up later if I have an opportunity to use a different amplifier.

 

[boingoman]

so is a passive DI not a good choice to initially get that good direct signal?

No. For one, passive DIs drop the signal level an average of 20db. Guitar signals are pretty weak to start with.

For another, guitars like to see very high impedance, like 250,000 ohms and above. A passive DI plugged into a mic input will have about 20,000 ohms. The result is more signal loss, reduced frequency response, and overall degredation of the sound.

Something I just thought of- you said you used this DI into your Delta. I'm guessing you used the 1/4" out on the DI? If so, no wonder you saw no change. The 1/4" out on a DI is just connected to the input jack. It doesn't pass through the DI circuit. It's really a "through" jack. It allows the original signal to pass through the DI unaffected. Very commonly used in live work for bass, for instance. Bass signal goes into DI, and to amp from out jack. DI signal goes out through XLR to mixing console.

DIs are used to convert to balanced lines, usually through an XLR. Most DIs don't have 1/4" DI outputs.

 

[darkecho]

Actually I was using an XLR-TR cable... sounds kind of useless right? haha

I need some XLR-TRS cables but didnt have any, the closest thing I had was that, and I wanted to use the balanced output but then again, TR isnt balanced, so Im not sure what I accomplished there....


so, should I return my passive DI and get an Active one for recording the guitar signal untainted into my DAW?

 

[boingoman]

so, should I return my passive DI and get an Active one for recording the guitar signal untainted into my DAW?

Using the XLR to TS probably dropped your signal level even farther.

I'm a gear whore, so I never return anything. A passive Di can be useful to have, but if this is the purpose, yeah, get an active or dedicated guitar pre. Whirlwind, BSS, Countryman, Radial, all make good actives. Some have had luck with the Behringers, I haven't but YMMV. There are also lots of more exotic choices, lots of mic pres these days have decent DI inputs. Just make sure the input impedance is at least 250K for good electric pickup loading.

 

[darkecho]

hmm... well I invested heavily in a D.A.V. BG-1 so if I can save some money by somehow using the BG-1 as my guitar pre, I woudl liek to do that...

It seemed to boost my DI signal ... or would that have worked if I used a tr cable into the guitar to an XLR into my mic pre?

 

[RAK]

So far I've read that DIs convert an instrument signal to line level, and to balanced signal.

A DI converts the instrument signal to mic level (usually via a balanced XLR jack) so that you can plug that into a mic level pre-amp (like on a console).

The 1/4" output on the DI is just a "thru" as was described, which allows you to route the instrument signal to an amp (for example) Then you can mic the amp and get two different sources.

Passive DIs have transformers which offers noise/hum cancellation. That's what I know about that.
Active DIs need phantom power.

 

[boingoman]

A DI converts the instrument signal to mic level (usually via a balanced XLR jack) so that you can plug that into a mic level pre-amp (like on a console).

Well, you could do that with a resistor and a cable. DIs aren't about level change, really. That's a useful side effect of using a transformer. Many active DIs don't have any change in signal level at all, unless you want it.

A DIs main purpose is to be an interface between high-impedance unbalanced sources and balanced low-impedance inputs.

 

[ermghoti]

A DI converts the instrument signal to mic level (usually via a balanced XLR jack) so that you can plug that into a mic level pre-amp (like on a console).

This is entirely right. I have been on the edge of seeing double for a couple days, and really should step away from the Internet. Somebody stop me before I post again!

 

[boingoman]

This is entirely right.

No, DIs are about impedance, not level.

 

[RAK]

Well, you could do that with a resistor and a cable. DIs aren't about level change, really. That's a useful side effect of using a transformer. Many active DIs don't have any change in signal level at all, unless you want it.

A DIs main purpose is to be an interface between high-impedance unbalanced sources and balanced low-impedance inputs.

a mic level input is a balanced low-imedance input (generally speaking).
Perhaps we're saying the same thing.

and now I will look up Direct Injection on Wikipedia (drum roll please...)

"It converts the High impedance(HiZ) output of an electric guitar pickup, to a low impedance(LoZ) output, suitable for connection to a microphone/line input of an audio mixer.

This technique was developed by Audio Engineers at Abby Road Studios during the mid 60's for the Beatles."

When I said mic level, I assumed low impedance.

 

[boingoman]

Perhaps we're saying the same thing.
.

Sounds like it.

 

[RAK]

Sounds like it.

Agreed. Looks like there will be no challenging to a duel here today.