Does a DI box do more than just match impedance?

[OrderedAudio]

I have a profire 2626 and i've been having a hard time getting a good bass tone using the line level input and there is an obvious improvement in my tone with my new passive DI box and I was wondering if its purely impedance matching that is improving the quality of my bass tracks or theres something else going on in the DI box.
thanks guys =D

 

[voidar]

It's just the impedance matching/conversion.

 

[LeSedna]

it is its purpose yeah, but as a Di Box is made of real-world (understand: not just numbers and maths equations) components, the results vary, and the best/most transparent sounding is not always the one that matches impedance the best on paper.

Although the profire 2626 has pretty decent hiZ inputs, a dedicated DiBox definitely improves the tone. I did a shoot out some time ago here between my profire and my box and the difference was surprisingly easy to hear.

In a nutshell : that's perfectly normal you hear an improvement, although the only purpose of a DiBox is still matching impedance.

 

[Kohugaly]

I've read, that transformers generally also add some higher harmonics to the sound. most devices working with electric sound signal have transformers in them. probably it is one of the many things, that make difference between analog and digital sound.

 

[JakeAC5253]

Active DI boxes have amplification stages in them, and whenever you have amplification, the design itself becomes a very integral part of the sound. Some active DI boxes like the Countryman Type 85 FET based DI, adds a sort of pleasing compression and coloration to passive instrument level signal. I spoke to a seasoned engineer a while back about purchasing one, and he said that he had known quite a few guitar and bass players who ended up purchasing one to use in their live rig ever since plugging their instrument into one while working with him. There are other designs which seek to provide the cleanest, spankiest sound with as little coloration as possible, these are typically your passive DI's. Cheap chinese DI boxes, it doesn't matter whether they are passive or active, they are going to sound like junk.

 

[ahjteam]

DI boxes isn't "just" an impedance mather. It:

- makes the signal symmetrical (from unbalanced to balanced)
- work as galvanic separator (removes ground loop problems if they exist)
- amplifies voltage (some boxes)
- decreases output (pad)
- decreases impedance (from 1M ohms to ~250)
- works as a signal splitter (unbalanced "input" jack to balanced XLR output and unbalanced "thru" jack output)
- they also might have some extra options on better boxes like phase invert, low cut merge two mono signals to single mono signal etc

 

[Leon--]

A good passive DI box will NOT colorise the sound,But the correct impedance will have a great result on your mix and you will notice the difference.
An Active DI box will infect your sound,in a good or a bad way(depends on the quality-price it)

 

[locus_coeruleus]

so what is better, a good active DI box or a good passive one?

 

[JakeAC5253]

so what is better, a good active DI box or a good passive one?

Thats really a personal decision. I and others have stereotyped the passive vs. active difference, but thats really only scratching the surface of the truth. There are good/great units on both sides and they will all impart some sort of character either to the EQ curve or dynamic response. If you can, try to get your hands on a few different units to try out and see what works for you.

 

[locus_coeruleus]

I actually can't, I don't live in the US and in my country there's no return policy. I was asking because I am traveling to the USA in 2012 and I'm considering buying a DI box. Thanks for your input, though, I will keep reading about them to make up my mind.

 

[mburton21]

My Radial J48 is fucking amazing; I use active pickups though. For passive pickups I've heard from a few sources (our own Glenn Fricker being one of them) that it is better to go for the countryman type 85.

 

[locus_coeruleus]

dammit, what if you have guitars with actives and guitars with passives? haha

 

[Leon--]

For guitars and bass(both with active pickups),i prefer Passive DI boxes cause they sound more natural to me.
you can also have killer results with active DI's no doubt,i just prefer passives.

 

[OrderedAudio]

Thanks for all the replies guys!
super helpful and now I can make my own decisions about how I would like my DI box for the future.