#1
Is DI box essentially a cab sim in a box? Are they used for the same purpose? Or are they something completely different?

If there already was a thread discussing this, please post the link, I couldn't find anything.
#2
A DI box (Direct Box) converts the 1/4 signal of the guitar to an XLR signal. Or rather, high-impedance unbalanced, to low-impedance balanced.Many of them have other bells and whistles, though. https://en.wikipedia.org/wiki/DI_unit

A Cab Sim/Speaker Sim applies a filter to the signal to emulate a speaker's frequency response.

So to answer your question, no they are not the same.
Last edited by Will Lane at Jun 7, 2016,
#3
Thanks. I've read multiple times though that DI boxes allow connecting the output of an amp directly into a PA system without it sounding like crap. Sounds like the definition of cab sim. Hughes & Kettner's Red Box does simulate a cab. So is cab simulation on DIs just an optional feature that some of them have?
#4
Quote by Rimšiakas
Thanks. I've read multiple times though that DI boxes allow connecting the 2. output of an amp directly into a PA system without it sounding like crap. Sounds like the definition of cab sim. Hughes & Kettner's Red Box does simulate a cab. 1. So is cab simulation on DIs just an optional feature that some of them have?
1. Yes.

2. I think you are thinking of both an attenuator and a cab sim. If you are using the powered output on the amp to the PA, it will first need to be brought down to a low level signal that will not fry the sound board (attenuation), as well as since the signal has not had a speaker response applied to it so the box applies one (cab sim).

The Red Box you listed seems to be kind of like an attenuator. You hook up the powered out from the amp to the input of the Red Box, which the box will send a cab-sim'd, low-level signal through XLR to the sound board. But, it seems as though you still have to hook the 1/4 output of the box back to the speaker cab, which allows the powered signal to pass through the box. This is because Tube Amps need to have a proper speaker load, measured in Ohms, attached to the power amp or you will destroy the amp.

To help clarify by making things more muddy, it seems as though we classify DI's as anything that takes any other type of electrical audio signal and makes it a low impedance, balanced signal. DI stands for Direct Injection, so it just means you go into the sound board directly, safely. So the kind of signal you have that is converted to that low impedance, balanced, safe signal, is really how you define the type of DI you have.
Last edited by Will Lane at Jun 7, 2016,
#5
This one really confuses the issue. Its got speaker level inputs too

http://hughes-and-kettner.com/wp-content/uploads/2014/03/Red_Box_5_BDA_1_1_D_E.pdf

If you go to a studio and talk about a DI, the engineer won't be in any way talking about something that you plug a speaker level input into and definitely not about something attempting to alter the sound the way a cabinet emulator would, they're looking for a way to get as unaltered a sound from the guitar as possible into a mic preamp
#6
That thing claims it can also be a DI but its input impedance is only 10k ohms, at least a factor of ten below what you would normally think is necessary