Help me understand DI out....

lustycourtier

Im gigging a lot on bass currently, with an Ampeg Rocket with a HX Stomp in FX loop. I DI out to PA, but Ive been thinking the sound coming out PA (and to my IEMs) must be different to amp as the amp has a speaker after power section, or am I over thinking this? Embarrassing to ask, but how does DI work?  

maltingsaudio

The Di out normally take the signal after the preamp and befor the power amp section of an amp . It should therefore contain your preamp sound and any effects in the loop, and your correct in thinking the sound coming out of the Di will differ to your ears hearing it from the bass stack. It will also sound different in your ear monitoring for the same reason., But in the room this difference is negligible. If you want the full bass sound in your ears then put a mic on your cab and use that send for monitoring.

UnclePsychosis

Literally all a DI is is a way to take an instrument level signal and convert it to a format that is compatible with a mixing desk / studio electronics.

So all you're doing is tapping into your signal chain at some point, and sending it to the PA. Amps with DI capability tend to have information in the manual that tell you where the DI is relative to the tone stack, etc. 

You are correct that the sound you hear coming out of your amp "could" be different from the DI'd signal because the power section and speakers will probably add their own tonal quality. 

Lots of people would therefore put a speaker sim or IR "on" the DI'd signal (the Stomp lets you do this) but lots of people would also say you don't need to - particularly for bass guitar where DI solutions are a lot more common than they traditionally have been for guitar players).

Basically - if it sounds good, don't mess with it. If it sounds shit, you may want to add some additional processing to the DI signal. 

thecolourbox

What I've always wondered, and this is probably a really stupid question but here we go, is when it's a DI which taps a signal out, or for example if you have a splitter pedal which splits your signal into two, does it decrease the amount of signal going through. So like say you have 100% of your signal before the DI and that all goes to the amp then speaker. By taking a tap out for the DI, does that mean you're only getting 98% (for example) going to the amp?

Or if you use a splitter, output A & B are at 50% each of what would have flowed through? But having had splitter pedals I know that isn't the case, so I just wonder how it happens. I think with the splitter thing, typically I'd say it was 90% the same on both outputs, which doesn't seem to add up in the way I'm thinking it works

ICBM

If you're using a clean sound then the difference between the DI sound and the sound from the speaker is largely a matter of EQ (due to the speaker's natural voicing), and since the soundman will almost certainly EQ the signal at the desk anyway it doesn't really matter.

However, if you're using an overdrive/distortion/fuzz sound then the difference is huge, because the speaker cannot reproduce the high frequencies at all really - which is why full-range cabs (and even some bass amps) have tweeters - and although to a degree it's still 'EQ', you generally need a dedicated speaker emulation device or plug-in to get it to sound right.

UnclePsychosis

thecolourbox said:

What I've always wondered, and this is probably a really stupid question but here we go, is when it's a DI which taps a signal out, or for example if you have a splitter pedal which splits your signal into two, does it decrease the amount of signal going through. So like say you have 100% of your signal before the DI and that all goes to the amp then speaker. By taking a tap out for the DI, does that mean you're only getting 98% (for example) going to the amp?

Or if you use a splitter, output A & B are at 50% each of what would have flowed through? But having had splitter pedals I know that isn't the case, so I just wonder how it happens. I think with the splitter thing, typically I'd say it was 90% the same on both outputs, which doesn't seem to add up in the way I'm thinking it works

Herein

 Herein lies the magic of circuit design. All of the things you say could be what happens, depending on how good the designer was at their job... 

Bod

ICBM said:

However, if you're using an overdrive/distortion/fuzz sound then the difference is huge, because the speaker cannot reproduce the high frequencies at all really - which is why full-range cabs (and even some bass amps) have tweeters - and although to a degree it's still 'EQ', you generally need a dedicated speaker emulation device or plug-in to get it to sound right.

This.  It's amazing how many sound engineers don't understand this.  I play with a moderate amount of distortion from my Sansamp Bass Driver into the amp, and hate it when they come up, lash an XLR into the DI and bugger off. 

The sort of gigs I play never have decent monitoring, so I can't just ditch the amp and go direct using a modeller, so I'm considering using a splitter with one path into Sansamp -> Amp, and another into my Valeton GP5 purely for front of house.

ICBM

Bod said:

It's amazing how many sound engineers don't understand this.  I play with a moderate amount of distortion from my Sansamp Bass Driver into the amp, and hate it when they come up, lash an XLR into the DI and bugger off.  

The sort of gigs I play never have decent monitoring, so I can't just ditch the amp and go direct using a modeller, so I'm considering using a splitter with one path into Sansamp -> Amp, and another into my Valeton GP5 purely for front of house.

I use a Superfuzz pedal, so sound engineers get a big (and potentially tweeter-damaging) wake-up if they think they can just DI before the amp input, as many want to… not even from the amp’s DI output. I take a Behringer BDI-21 (the clue what that’s a copy of is in the name ) to fix that problem if I have to - it actually sounds OK in front of the amp, even though that’s speaker emulation going through a real speaker. To be honest I’m not that fussed about my bass tone on stage - if I can hear it clearly it will do, and I’ll trust that it’s ok in the FOH. I should probably get a splitter - or just mod the BDI-21 - so I can run them separately like you’re thinking of.

lustycourtier

That all makes sense cheers. 

maltingsaudio

Quick comment re Di out, I prefer to take  the DI out from a bass amp , it’s quick and easy and unless the tech rider says different that’s what I’ll do. It doesn’t really make any difference to the sound of the mix if it comes from the DI or a mic. 

Some DI outs can produce extra noise, or in the case of the Orange tiny terror bass amp original just be designed with too much output. In this case a Di with a through is used, so signal from guitar post pedals into Di , through from DI into amp and out from DI into PA. 

Always a good idea to turn phantom power off on the bass line if taking a DI out but it shouldn’t do any harm .

Active or passive DI doesn’t really make a difference, however the quality of Di does

ICBM

maltingsaudio said:

I prefer to take  the DI out from a bass amp , it’s quick and easy and unless the tech rider says different that’s what I’ll do. It doesn’t really make any difference to the sound of the mix if it comes from the DI or a mic.

I assume you mean for clean sounds! Or do you have speaker emulation on the desk?

maltingsaudio said:

Active or passive DI doesn’t really make a difference, however the quality of Di does

I prefer passive transformer-based DI boxes for electric guitar, but also if possible for bass - they’re more natural-sounding, even cheap ones compared to good actives. I prefer active for purely clean sounds (eg keyboards) and acoustic instruments.

maltingsaudio

ICBM said:

maltingsaudio said:

I prefer to take  the DI out from a bass amp , it’s quick and easy and unless the tech rider says different that’s what I’ll do. It doesn’t really make any difference to the sound of the mix if it comes from the DI or a mic.

I assume you mean for clean sounds! Or do you have speaker emulation on the desk?

I have eq on the desk, I have always worked on the  principle that the sound sent to me has to be amplified and adjusted for the room. It is down to the musician to send me the sound he/she wants the audience to hear, any drastic intervention by me has to be agreed before the gig starts. 

That said I’ve never come across a bass sound which I think could benefit from cabinet simulation, modellers on the other hand are a completely different headache of fish.

ICBM

maltingsaudio said:

That said I’ve never come across a bass sound which I think could benefit from cabinet simulation

Even with a Superfuzz? It’s absolutely brutal DI’d - probably the widest frequency range fuzz pedal I know of - you could probably tame it with EQ if you have to, but cab simulation is easier.

MartinB

My superfuzz DI solution is a Schalltechnik Vong HPF/LPF pedal - it has a variable 12dB/octave low pass filter which at the right setting can take the worst high end off the DI signal without affecting anything below that. I have the setting marked on the knob, through trial and error listening both through headphones and through my cab I found a spot where I'm pretty sure it starts rolling off just above the useful high end of the cab. Through the cab, the fuzz sound is just perceptibly darker with the LPF than without, and I hear no difference with my non fuzz sound. But through the PA the crazy broken sounding fizz is gone. 

That sits at the end of my small pedalboard in front of the amp, and I usually use the post-everything DI output on my Ampeg PF50T that's padded down off the speaker output. Although a lot of people consider a DI earlier in the signal chain before the amp EQ to be best practice, it sounds good that way and no sound person has ever complained about it. 

But for the OP using the HX Stomp, I'm sure you can find a suitable speaker sim on board to tame any overdrive or fuzz sounds through the PA. 

maltingsaudio

ICBM said:

maltingsaudio said:

That said I’ve never come across a bass sound which I think could benefit from cabinet simulation

Even with a Superfuzz? It’s absolutely brutal DI’d - probably the widest frequency range fuzz pedal I know of - you could probably tame it with EQ if you have to, but cab simulation is easier.

TBH I very rarely know what pedals or effects the musicians are using, I tend to get sent the signal and deal with it. 

The norm at a soundcheck is plug in and sort, the opportunity to chat about the gear folks are using are few and far between. I don’t work with one band all the time, so far this year I’ve probably mixed over 100 different ones. The constant is my equipment and how it works ,