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Multi-mic mixing technique

Place a dynamic mic an inch or two away from the guitar speaker grille. Angle it at 30 degrees so it points between the cone and speaker edge. Small changes in placement have a huge effect; search for the best tone. To search for the best placement, wear headphones, and play back a clean/direct guitar loop recording into the guitar amp.

In addition, place a condenser mic a few feet in front of the cabinet, a foot above the cabinet, angled down at the cabinet. This captures room resonance (reverberation with particular EQ characteristics).

Run these mics into separate channels of the mixing board. Adjust the relative levels of the channels for frequency cancellation and summation.

Find the best-sounding speaker in a multi-speaker cabinet. Try different speaker types and different cabinets.

Place sound-absorbing material on the floor between the far mic and the speaker cabinet to avoid or affect the reflected sound waves -- phase cancellation is intense, with microphones.

You can also use the tone controls of the mixer channels or use a parametric EQ or graphic EQ for each mic. Whatever sounds good. The convention is to do everything you can to dial in good tone via mic technique, and only then, use electronic equalization.

A large part of the strategy of recording Stevie Ray Vaughan was to set up many amps, many cabs, and many mics, all feeding separate channels of the mixing board. With so many signals to choose from and blend during mix-down, who could fail to find a really killer Tone in the studio monitors and capture it in the master recording? "Amp Tone" then becomes a matter of searching through the various combinations of mixing-board settings, after, and in addition to, adjusting the controls on the amps. These are distinct processing stages: getting great Tone at the guitar speakers, vs. getting great Tone at the mixing board's output. The art of recording guitar requires these primary realms of adjustments:

  1. Adjusting the amp controls to get the best tone at the speakers.
  2. Adjusting mic placement and choosing speakers and cabinets.
  3. Adjusting the blend of mic signals at the mixing board.
You can combine these conventional techniques with innovative thinking about the packaging of guitar-processing technology. You can use a multifx processor to essentially fold a mixer back into the guitar processor. You can use a speaker isolation cabinet to fold the control room vs. music room isolation into a more compact, self-contained guitar rig: the "recording studio in a box". An advanced, truly complete guitar processor would incorporate a power tube and preliminary speaker out jack, and multiple mic returns, then support blending of the mics, and adding post-mic effects processing (EQ, compressor, time-effects). Finally the signal could be sent to a mixing board -- instead of using multiple mic channels there, just a single guitar channel would be needed, since multi-mic blending could take place inside the guitar processor. The principle of design here is to look at the components in the total processing chain in a professional recording studio, and put all of those components, in non-simulated form, into a single guitar processor box. The box would support both approaches: the power tube could drive a guitar speaker and mics, or a load-and-filter; with either option, the signal continues for post-processing, and then is ready for final mix-down with the other instruments in the separate mixer. This completeness of processing puts complete tone-generation control in the hands of the guitarist, rather than relying on a studio engineer in a separate control room to apply post-amp processing. The signal coming out of the processor would include the sound of power tubes, guitar speaker, blended multiple mics, and post-amp processing -- completely authentic and fully ready for final amplification, monitoring, or recording.

Using a power tube, speaker, and mic in a processor's loop really goes entirely beyond the conventional assumptions about DI, which typically assume that the power tube, speaker, and mic are completely omitted. I just propose to *move* these elements into the middle of the guitar processor. Rather than doing this chain:

conventional tube amp and speaker and mics
multiple channels of conventional mixing board
post-amp effects processor

I propose:

preamp/processor section 1 including power tube
speaker and mics [or load-and-filter]
preamp/processor section 2 including multi-mic mixer module
single channel of conventional mixing board

This new type of "DI box" would not *eliminate* the power tube, guitar speaker, or mics, or multi-channel mic mixing, but actually just *relocate* them back toward the guitarist, away from the master mixer and recording engineering in the control room. This would enable fully programmable control of a complete processing chain including multi-miked speaker and post-mic processing, which a conventional recording studio setup does not conveniently, explicitly support, all in a single processor rather than having to purchase and cobble together two separate processors together with a separate tube power amp. Combine the two processors and the tube amp into a single unit. Only the guitar speaker cabinet and mics need to remain outside the processor box, and even those can be replaced by a load-and-filter when necessary. A built-in sweeper/analyzer/auto-equalizer would help normalize the response of the speaker/mic loop. For reproducing the desired preset sounds, some sort of mic placement guide would help -- or a programmable robot arm, to move the mics in a controlled way in the speaker's sound field.

These techniques can be used for a speaker isolation cabinet. The raw sound of a mic inside a closed-front cabinet tends to sound more constricted than miking a conventional cabinet, so it needs extra EQ and reverb processing and multiple-mic blending, to make the speaker sound open again -- especially since you can't adjust the mic position when the isolation cabinet's door is closed. Again, a sweeper/analyzer/auto-equalizer would help normalize the response of the speaker/mic loop.

I don't know much about mikes, but I found this on the Net. I found the SM57 to have an overly constricted sound, and am looking for alternatives.

Cypher wrote: "The two Audix mics were really the star of the show. Everyone commented on how clear the vocals were. The Audix OM-3xb and OM-2 are both exceptional mics in my opinion. Forget the SM57 or SM58, forget the $300 EV dynamic mics. The Audix OM series are the best dynamic mics I've ever heard. Awhile back, several people on the 'net suggested the OM-5 which got me looking at the Audix mics in the first place. (Also, I once heard Doyle Dykes play a Taylor guitar mic'd with an OM-5, and it sounded beautiful.) After A/B'ing the OM-5 and the OM-3xb, I preferred the sound of the OM-3xb. Later, I got the opportunity to test the OM-3xb and the OM-2 against a sound-proof room full of other mics (20+ mics). To my ears, NONE of them sounded better. The OM-2 was also a great performer - very similar sounding to the OM-3xb even though it uses a different capsule. The OM-2 has a more flat response which many vocalists search for. (I only paid $99 for the OM-2 which is a steal in my opinion.) Another thing to note about these mics is their excellent feedback and noise rejection. Unless you point the thing right at your PA speaker, these mics won't feedback at all. They have some of the best off-axis noise rejection I've ever heard. The only drawback to this is that you have to stay right in front of the mic to be heard. When you're playing guitar, this can sometimes be difficult. After working with these mics for a little while, you get to know their "sweet spot", and you can train yourself to stay on the mic. If you're the type of person that just can't stay on the mic while you're singing and playing, I'd suggest some of the new super-cardioid condenser models that are available. The Audix mics are famous for their gain before feedback, and off axis rejection. The Beta 58 doesn't have the feedback resistance that the Audix mics do. The salesperson demo'd the SM58, the Beta 58, and the OM-5 and OM-3xb. The 58's both hit feedback at much lower gain. I witnessed this myself. Also, you can sing into the sides of the SM58 and the Beta 58 which may be good in some situations, but that simply means that they're more prone to off axis noise. The OM-series are not. You can yell into the side of the OM-series and it won't pick it up. You've got to be right on the mic. The cardiod pattern is extremely narrow: http://www.audixusa.com/omseries.htm Compare these patterns to the Shure's. The OM-2 won Electronic Musician's Editors Choice award, beating out the SM58. http://www.audixusa.com/OM2-EM1999.html In the various reviews on their website, a common theme among the OM-series mics is the excellent gain before feedback."

great condenser mic for guitar amps

amp miking

xxx "Heavy metal, that is. To test the TC40K's ability to stand up to ridiculous SPLs, I stuck my Peavey Classic 50 amp in a closet, turned up its volume, shoved a TC40K right up to the front of the speaker, covered the whole thing with two thick blankets, and then shut the door. I plugged in my Les Paul with Zoom Driver set to Metal mode and made all sorts of ungodly racket, running the signal directly into my Kurzweil K2500."

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