Speakers and microphones

About microphones

Impulse responses are captured using microphones.

"Using a "neutral" IR with a simulated mic does not sound the same as an IR using that mic. It simply can't. Neutral mics like the Earthworks TC series are nearly omnidirectional. They operate by using a very small aperture as compared to traditional mics that have effective apertures orders of magnitude bigger." [1]

"The mic I've been most impressed with for recording guitar lately is the Beyer M160. I don't like SM57's alone for amps. They're too spikey and compressed but mixed with an M160 or R121 they add some nice sizzle." [2]

"The M160 is an awesome guitar cab mic. All the IRs we got with the M160 came out really nice." [3]

"My typical workflow is to choose an R121 or M160 first as these have the best low end. Then I choose an IR from one of the other mic types to get the desired brilliance. This is usually an SM57 or 4047. I just don't like 906s or 414s but that's me. I leave the panning at default but that's just my preference." [4]

"If you get a chance try a Shure KSM313, an AEA R84 and a Beyer M160. The KSM313 is now my preferred mic for guitar cabs. I like it better than the R121. I find the KSM313 a little more balanced. The R121 has a lot of bass and proximity effect and the high end can be a little dull." [5]

"My favorite mic for guitar cabs is the KSM313." [6]

"Certain mics like the royer 121 have 2 sides (front, back). Each has a different sound. Back side of the R121 is a bit darker. The difference between the front in the back is only apparent at closer mic distances. Get out past 3 feet and the sound the same on either side."

"The M160 is a good mic but there are better ribbon mics. My personal favorite is the KSM313. It's more balanced and has better high frequency response. I haven't tried the KSM353 yet but I imagine it's even better. [7]

"IMHO nothing beats a KSM313 for "neutral" close mic'd IRs." [8]

Dyna-Cab cabinet/microphone modeling:

"We actually used six mics during the captures, two of each type. I picked one from each type that I thought sounded best. The dynamic is an SM57 (naturally). I actually prefer the SM7 captures we made but given how iconic the 57 is on guitar cabs I went with that instead." [9]

"You can mix up to four Dyna-Cabs. You can mix-and-match any combination of cabs and mics. Position sets the radial distance of the microphone from the center of the speaker. Distance sets the distance from the grill cloth. As you move the mic away from the grill the bass typically rolls off and more room is heard." [10]

Dialing in Your Tone by Red Wirez provides useful info about mics and mic positioning.

Wikipedia:

• Shure SM57
• Shure SM58
• Shure Beta 87A
• Neumann U87
• Royer R-121
• AKG D112
• Neumann U67

Additional information about microphones:

• http://www.soundandrecording.de/tutorials/mikrofonvergleich-vor-dem-e-gitarrenverstaerker
• Wikipedia
• http://soundschematic.com/dynamic-ribbon-condensor
• http://www.barryrudolph.com/stellar/guitar.html
• http://www.gearslutz.com/board/so-much-gear-so-little-time/201972-mic-standards.html
• U67
• SM57
• SM58
• MD421
• U87
• D112
• Beyer M160, Beyer M160
• Sweetwater: Guitar Cabinet Mic Shootout – with Sound Samples
• The Importance of Mic Placement for Guitar Amps – with Sound Samples
• What's the difference between Shure SM57 and SM7b

From "The SOS Guide to Live Sound" by Paul White:

About guitar speakers

Impulse responses reproduce the sound of a speaker cabinet. Here's some background information on guitar speakers.

• Speakers: the final frontier
• Legendary Tones: G12M versus G12H
• Sound On Sound: choosing guitar-amp speakers
• Sound on Sound: understanding and recording guitar speakers
• Rivera: 15 speakers compared (YouTube)
• Eminence tone guide
• Fenderguru: selecting speakers
• Celestion history
• Pre-Rola greenbacks explained, part 1
• Pre-Rola greenbacks explained, part 2
• Premier Guitar: how a speaker cabinet influences your tone
• Leon Todd compares IRs of V30s
• Sound clips of Celestion speakers on SoundCloud
• Meet a true Guitar Speaker Expert from JENSEN Speakers
• Every Celestion Speaker Compared!
• ML Sound Lab: How To Mic Up Guitar Cabs Like A Pro

Jensen speakers:

• P12R: 12”, 15W
• P12Q: 12”, 20W
• P12N: 12”, 30W
• P10R: 12”, 15W

"Break-in is definitely real with guitar speakers. The surround is stiff when new due to the doping. I don’t think monitors and hifi speakers exhibit any significant break-in." [11]

"We witnessed speaker break-in first-hand when shooting IRs. We bought a brand-new 5150 III cabinet. Went to shoot some IRs and they sounded terrible. So I put the synth block on and ran the speaker for several hours while we were doing other stuff. Came back and shot some IRs and they were much better sounding." [12]

How a speaker works: electricity runs through the voice coil (wire), creating an electomagnetic polarity that shifts depending on the input signal. This makes the coil move closer or away fom the magnet.

Ohm = AC Resistance (not: AC current) = impedance. Adding speakers in series increases resistance, adding speakers in parallel decreases resistance. Examples:

• 2 identical speakers wired in parallel: combined impedance is half that of the individual speaker (2 x 8 ohm = 4 ohm)
• 2 identical speakers wired in series: combined impedance is doubled (2 x 8 ohm = 16 ohm)

From "The SOS Guide to Live Sound" by Paul White: