Miking A Guitar Amp
Oh how I love miking guitar amps and getting a great guitar sound. It's one of the most satisfying things to do in the studio. As a guitar player, I'm probably biased, but for me it's also one of the most important techniques to know. I'm not going to try to cover every way of doing it, I'm just going to discuss my approach. Hopefully it can help you!
I find that the biggest reason for failure in miking a guitar amp is because of the amp itself. We've all heard the phrase, "you can't polish a turd," and that's because it's true! Get yourself a dang good amp, or don't even bother. I find a lot of engineers resort to digital sources such as Kemper profiling amps, AxeFX, BIAS, etc. While these approaches are making significant leaps, to my ears they're just not there (just my opinion!). I think they will be there soon though. But for now, get yourself a killer amp! Here's a few amps I like:
- 65 Amps Soho
- Framus Cobra
- Bogner XTC
- Mesa Dual Rectifier (Revision F)
- Vox AC30 HW
- Fender DeVille
- BadCat HotCat
- Matchless DC30
Yikes I have expensive taste! It's gotta be done though.
So my typical arrangement is 4 microphones. I'll start with my go to setup:
- Shure sm57 (against amp mesh)
- Shure sm7b (against amp mesh)
- Sennheiser md421 (against amp mesh)
- Neumann u87 (room mic, usually behind and in omni-directional)
This is my go to. I use my phone flashlight to get all the mic's positioned on the speaker. I always start with the mics pointed at the edge of the dust cap (round center part of the speaker). In general, the closer to the center of the dust cap, the brighter the sound is, and the further out on the speaker, the darker the sound is. I like the edge of the dust cap as good balance point.
Make sure that you align for phase while miking. For instance, the capsule for the sm7b is a bit further back in the microphone chassis than the sm57 and the 421, therefore you should have the 57 and 421 about a quarter inch further back than the sm7b. This will give you a great phase relationship.
For the room mic, I try to wrap the amp in baffles, and put the room mic behind the baffle. If it's an open back cabinet, I'll put the room mic right behind the amp instead. I use omnidirectional to capture the entire room, but that's a taste thing. You can put the room mic in a different room as well. Lots of 'room' to explore here...see what I did there ;)
Some alternative mic choices I occasionally use:
- Neumann m147 - sounds super warm against the grill for a light gain sound
- AKG C414 - These mics work on everything. It's ridiculous. Rooms or close up work great.
- Sennheiser e609 - Not my favorite, but sometimes they work great.
- Royer r121 - This will probably be the next mic I buy, as I don't yet have one. Super creamy delicious warm goodness :)
SUMMING AND PROCESSING
Once the mic's are set, it's time to get into the control room and tweak. First, I'll check all the phase. I'm not doing anything crazy like white noise null testing, simply checking to see that all mic's are pretty well in phase by solo'ing two channels, flipping the phase on one of those channels, and seeing how well the signal drops (because I put them 180 degrees out of phase). If the phase looks good, I start playing with the level of each mic on the faders. This is because before we grab an EQ, I can balance the level of each mic to tailor the sound to the song, a natural way of EQ'ing. If that just isn't working, I'll go adjust a mic or two.
Once we've got a balance for the mics, I then immediately sum it through the mix bus on our SSL Matrix 2. This can be done on any summing box, or in the box...you know, the computer one. I typically drive the SSL a bit more, pulling back the master fader to make sure the level coming back through the converters is appropriate.
Once the summing balance is set, I have a go to set of UAD plugins for finishing the sound. I use a UAD SSL EQ to high-pass some of the low frequencies (typically 80 - 120 Hz), lo-pass some of the top (usually about 10k), and maybe work on the mid range. Next, I use a UAD Pultec EQP-1A for some high end at 8-10k (Pultec's are the best thing ever on guitars). This gives the guitar a TON of bite and energy. Incredible. Finally, we hit it with some compression using a UAD 1176 Rev A (blue stripe), knocking off about 3-6 dB, slow attack and quick release. Don't be afraid to smack the hell out of the signal too. Sometimes a really spanky clean sound will get 10-12 dB reduction. Trust those two things on the sides of your head...your ears ;)
And that's that! My guitar process in a nutshell. It can vary depending on the song, style, genre, band preference, but that's usually where I go.
Two quick notes. First, this post was all about amps, but the guitar used is equally important in the process. Secondly, the absolute most important part of getting a great tone is the player. Hands down. In fact, take that notion and multiply it by one hundred. If you can't play your guitar, it's gonna sound terrible, no matter what. If you are a phenomenal player, it's going sound great even on poor equipment (although it will sound even better on great equipment). This is numero uno! Make sure the playing is right. I think 90% of the guitar sound comes from your fingers. My two cents!
If you got any more tips or tricks or have any questions, comment below or email me at firstname.lastname@example.org!
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