Electric Guitar DI signal recording

[byxx]

Hi,

I am looking for thoughts on how to create a setup including a proper option of rercording the pure electric guitar signal. I would like to monitor through an Amp or modeller which might change due to backline in live situations etc. keeping the monitoring pretty modular while maintaining a consistant DI sound with one and the same device , I would say. (to be later edited in the DAW with Plug Ins, being reamped etc.)

Most concerning for me is the impedance topic. How does varying DI Boxes (varying impedances, active and passive) react to the output signal of the guitar jack?
What is the proper method to record good electric guitar DI sound?

THX!!

 

[HarmonicTHD]

Hi,

I am looking for thoughts on how to create a setup including a proper option of rercording the pure electric guitar signal. I would like to monitor through an Amp or modeller which might change due to backline in live situations etc. keeping the monitoring pretty modular while maintaining a consistant DI sound with one and the same device , I would say. (to be later edited in the DAW with Plug Ins, being reamped etc.)

Most concerning for me is the impedance topic. How does varying DI Boxes (varying impedances, active and passive) react to the output signal of the guitar jack?
What is the proper method to record good electric guitar DI sound?

THX!!

I run the E Guitar out directly into an audiointerface instrument-in input. From there into a DAW, where I add the effects (guitar amp, pedal effects, guitar speaker cabinets etc) and out into either speakers or headphones for monitoring and or into a track in the DAW for recording and later mastering.

One can do everything in a DAW, a modelling amp (or even guitar tube amp) can do, provided you have the right plugins.

I hope I fully understood your scenario and question. If not please clarify.

 

[DVDdoug]

I'm not a guitar player...

Audio interfaces with switchable mic/instrument inputs are common so you don't normally need a separate DI box. The instrument input is high impedance (like a guitar amp) so it doesn't affect the tone. With these high-impedance inputs you can use a splitter to drive an amp and interface at the same time also without damaging the tone.

The quality is usually fine, but usually "too clean" for electric guitar (without an amp sim plug-in). Except of course from the usual noise/hum/buzz problems with guitar.

I've read about some interfaces where the gain control doesn't go low enough (to prevent clipping), and guitar players often don't like turning-down the volume on the guitar.

One feature that's handy on an interface is zero-latency direct-hardware monitoring, where the monitoring doesn't go-through the computer. Of course, that means you can't hear a sim while recording. But if you've got an amp connected at the same time neither of those is important.

It's also quite common to stick a microphone in front of a guitar cabinet, or to record direct and with a mic at the same time on separate tracks.

Lower impedance loads on the guitar will lower the signal and knock-down the highs. Active pedals act as a "buffer" with low-impedance output so the impedance of anything after that has almost no effect.

 

[HarmonicTHD]

Hey! that are great insights. THX for your quick responses. I guess my main problem would be the splitting process when running the one guitar cable into the audio interface, where I would miss the through option of a DI Box for the analog monitoring of a physical amp or modeller. How to do it, when using a interface. The idea of directly record the pure guitar´ s signal into the Daw via interface is a good choice, sure!!

a) My ideal aim is to get both. Real amp Plus the DI signal- I think Lehle produces these kind of splitters...
b) In terms of values there are some DI Boxes out here with 1 MOhm, which I hear seems to be okay using it as Instruments Input

Most audiointerfaces have analog outs (mine does). One can program the signal routing of the interface to your individual needs so for example run the clean guitar signal out directly to a subsequent DI / Modeller. Just check the DI/Modeller input features as these should except an 2V/4V signal and not only clean guitar signals.

 

[Prana Ferox]

OP, this forum primarily deals with audio reproduction, while you may get some info here you may get more info on a forum dedicated to audio production

If you're worried about impedance matching the pickups, I would think you can run the signal through basically any preamp pedal first as a buffer, set as clean as possible. If that doesn't give the sound you're looking for, my advice is to blame the drummer

 

[bluefuzz]

What is the proper method to record good electric guitar DI sound?

In my experience there isn't one. At least when I attempted to record the direct sound of an electric guitar (admittedly many years ago) I found the results less than useful. It's not so much a problem of actually recording the guitar. Any high-Z audio interface will do. But the problem with 'reamping' is that the way you play the guitar is inevitably coloured by the sound you hear when actually playing. Adding a different amp or distortion inevitably sounds wrong because you would have played the guitar differently had you heard that sound during the recording.

It's not always a good thing to always leave your options open to 'fix it in the mix'. Much better to have the courage of your convictions and record the guitar though an amp with effects etc. in place and live with result.

 

[dominikz]

Hi,

I am looking for thoughts on how to create a setup including a proper option of rercording the pure electric guitar signal. I would like to monitor through an Amp or modeller which might change due to backline in live situations etc. keeping the monitoring pretty modular while maintaining a consistant DI sound with one and the same device , I would say. (to be later edited in the DAW with Plug Ins, being reamped etc.)

Most concerning for me is the impedance topic. How does varying DI Boxes (varying impedances, active and passive) react to the output signal of the guitar jack?
What is the proper method to record good electric guitar DI sound?

THX!!

Perhaps the approach I personally use to track guitars may be of some help. For simplicity I like to monitor through my practice amp (Yamaha THR10II) when tracking, but I also want to record the cleanest possible guitar DI signal which I can reamp later with my half-stack. I also want to minimize passthrough latency while also minimizing the CPU load on my DAW PC.

The way I do this is:
1) Connect the guitar to instrument/Hi-Z input of my RME Babyface audio interface
2) Configure RME TotalMix to route Hi-Z input directly to one of the analog outputs (e.g. AN1) - i.e. the so called "direct" or "hardware" monitoring
3) Connect the AN1 output of Babyface to the Yamaha THR10II guitar input via a "reamp" isolation box (basically a 1:1 balanced to unbalanced transformer in a box) - this means what I play into my audio interface is sent to my amp directly
4) Configure RME TotalMix to route DAW stereo master bus to the secondary analog output (e.g. AN3&4) and connect that to Aux input of the Yamaha THR10II (another isolation box might be needed here if you get ground loops) - this means that whatever plays on my PC is heard also through my amp (but without the guitar amp model applied)

With this setup I can monitor both guitar and the backing track via the practice amp, and control their relative volume balance directly on the amp's volume knobs, while tracking absolutely pure DI dignal direct from the guitar to the PC. Passthrough latency is also very low (1-2ms), as is PC CPU load, since I only use RME TotalMix "direct monitoring" feature without relying on DAW SW monitoring (which otherwise can introduce significant extra latency and/or tax the PC CPU).

Most concerning for me is the impedance topic. How does varying DI Boxes (varying impedances, active and passive) react to the output signal of the guitar jack?

Guitars with passive pickups have unusually high output impedance, meaning that an unusually high input impedance is also required to preserve high-frequency content. This is why guitar amps / DI boxes / guitar pedals / audio interface instrument inputs often have >500k ohm input impedances.

This is also why long, high-capacitance guitar cables can sound different to each other - when combined with the high output impedance of guitar pickup they can cause low-passing within the audible part of the spectrum (e.g. see this article). This is one of the very few exceptions where cables CAN make an audible difference (again, this is only due to the relatively unusual output impedance characteristic of guitar passive pickups; it doesn't happen with buffered sources). It is also why poorly-designed guitar cables can be more susceptible to handling noise.

Note that guitars with active pickups have low output impedance and therefore produce much more consistent output, which doesn't depend nearly as much on cable length, input impedance of next stage, or cable construction architecture. Note also that this is why some guitarists using passive pickups like to also use 'buffer' pedals in their rigs - it allows use of much longer cable runs post-buffer.

So in short, the "right way" to record guitar is to record into a very high-impedance input (either by using a Hi-Z/Instrument input on the sound card, OR by using a DI box into a line/microphone input).
If you want to preserve the purest guitar signal possible you should use a short (and ideally low-capacitance) guitar cable; but if you want to closely emulate the sound you get with a real amp you should use the same guitar cable you'd normally use with that amp (so you get similar low-pass effect).

Hope this helps!

 

[byxx]

So, with that you reported I would tend to just use a active DI Box around 1MOhm for a passive guitar PU. I appreciate the in depth discussion in technical terms here on how the instrument interplays with the DIs input. I have to reflect on that a bit regarding the crucial part of eliminating the Hi´s when impedances are not properly set up. So again: Many thanks for your effort writing here!! I am very interested in that which source sees what impedance thing IN vs OUT...elecricity (Signal?) flows in the direction of lowest resistance, I would assume, but I have to get my head around the frequency dependency a bit.I assume, when impedance of the DI Box is hi, it forms a proper resistance not sucking off the PU Signal too much?

 

[dominikz]

So, with that you reported I would tend to just use a active DI Box around 1MOhm for a passive guitar PU.

That's one valid way to do it, yes.

I am very interested in that which source sees what impedance thing IN vs OUT...

Guitar normally "sees" the high-impedance input of the amplifier, so an active DI box will emulate that well.

elecricity (Signal?) flows in the direction of lowest resistance, I would assume

That formulation is not entirely correct, but Ohm's law tells us that lower impedance means higher current (for a given voltage).
In audio we are normally interested in passing signal as voltage, so we're not that interested in current. The most efficient transfer of signal is achieved if output impedance of previous stage is much smaller than the input impedance of the following stage (look up voltage divider circuits).
This is why we need very high-impedance inputs for guitar gear.

I assume, when impedance of the DI Box is hi, it forms a proper resistance not sucking off the PU Signal too much?

Correct!
If you connected your guitar to a low-impedance input, a significant portion of signal would be lost on guitar PU high output impedance.
Add to that frequency-dependence of complex guitar PU impedance, and possibly significant cable capacitance, and you also get filtering on top (think of it as undesired EQ).

I have to get my head around the frequency dependency a bit

Best way to undestand the fundamental principles behind this is to look into Ohms law, serial resistor networks (i.e. simple voltage dividers) and basic electrical filters (e.g. low pass RC networks and RLC resonators).

 

[Multicore]

Use a Boss effects pedal in between the guitar and the interface with the effect turned off. (Or another brand that has buffered bypass.) I learned this trick from the Sound On Sound podcast.

 

[Eric Natural]

I use this one with success : https://www.mooeraudio.com/product/013---Matchbox--44.html
best of luck