MIC TECHNIQUES: AMPS

Thinking Outside the Box

By Brian Stephens

Even with the advent of digital guitar amp modeling from companies like Line 6 and DAW plug-ins like AmpFarm and Amplitube, there is still no substitute for a great guitar and amp that are mic’ed well. You will find, however, that layers of guitar tracks that are all recorded with the same amp, microphone, and mic placement tend to sound very flat or one dimensional in the final mix, even if you utilize different guitars/pickups for each individual track. By varying any one of the components in the guitarist’s signal chain, you can create sounds that, when combined, add more depth and perceived thickness to your mixes. Taking a few cues from one of my recent recording projects, let’s create a scenario to illustrate the variety of choices we have in getting guitar sounds.

For main rhythm guitars, we will rely on the old ‘tried-and-true’ method of placing a Shure SM57 microphone midway between the center and the edge of the speaker cone, right next to the cabinet’s grill cloth. This position works best because it provides just the right balance of richness and clarity (see pic 1). For a brighter tone, shift the mic closer to the center of the cone. For something smoother, you may elect to move the mic closer to the edge of the speaker. Here is the rest of the signal path for these tracks:

Gibson Les Paul Standard

Peavey 5150 amp head

Marshall 4X12 cabinet

DBX 376 mic pre-amp

Joe Meek MC1 compressor (set very lightly)

And there you have it, instant Roll-n-Roll rhythm guitar. The tube preamp and Joe Meek compressor are used to add a little warmth and richness to the recorded sound. We could record all of the guitar parts with this configuration with no problems, but once in mixdown, the sound of the overall guitar mix may be very flat and one dimensional. So, let’s look at some other sonic textures that will create some sense of depth for this song.

During the verse sections, we are going to use the same signal path as before except for two components. The use of a different mic and compressor will help to create a different sound for our verses. For mic’ing the cabinet, we will switch to a Sennheiser e609-silver, a replica of the now legendary MD 409 microphone and patch this new track into a Peavey VCL-2 tube compressor. The e609 is a mic with a flatter frequency response which captures more of the rich low end of the guitar tone. The tubes in the Peavey unit will give us a different kind of warmth from the Joe Meek box (see pic 2). Even though the guitar, amp, and cabinet have not changed, the results of this equipment switch will yield a noticeably different tone that will give each section of the song a different sonic fingerprint.

For this song’s cleaner, picked guitar tracks, we switch to a totally different setup (see pic 3). Here is the lowdown on the signal path used for these tracks:

Fender Stratocaster guitar

Tweed-style guitar amp with one 12î speaker

Oktava MK219 large diaphragm condenser mic

DBX 376 mic pre-amp

Peavey VCL-2 tube compressor (2dB of avg. gain reduction)

Condenser mics like this Oktava give you the detail that condenser mics are known for but, by using this particular mic, the end result is a grainer texture on the recorded track. This type of lower end, ‘budget’ mic does not have the same pristine sound quality as some of the more expressive condenser mics. It is this coarse sort of texture that helps make these parts stand out in the overall mix.

For guitar solos and the ‘color’ parts that are woven throughout the song, let’s take a different approach. The previous tracks have been recorded with an emphasis on mic’ing the speaker and getting a present, focused sound. For the next tracks, there is a technique to use that will keep the presence of the close mic while adding some ‘air’ or space to the sound, giving it more apparent width in the track. Here is the signal path for the solo guitar tracks (see pic 4):

Les Paul Jr. guitar

Trainwreck amp head

1972 vintage Ampeg 4X12 cabinet

Sennheiser e609 silver (close mic)

ADK A51s TC tube condenser mic (3’ in front of cabinet)

DBX 376 tube mic pre-amp (on both mics)

Peavey VCL-2 tube compressor (on both mics, light compression)

The close mic, this time placed closer to the center of the speaker cone, will give us a brighter tone with a lot of definition to each note. The ambient mic will catch the sound of all four speakers working together, the wood of this vintage cabinet, and a bit of the room itself. You may even wish to clone this track in the DAW, panning each slightly to the left and right of the centered close mic for more sonic width in the final mix.

But with all this talk about mic’ing guitars, we should not forget about our bass playing ‘partners-in-crime’. For bass guitar, we will take a multi-faceted approach. First, run the bass itself into a good direct box. From here, we will be able to split the signal and send it to a couple of destinations. The first place is to a quality tube preamp. For this move, make sure that the bass is well-grounded and that any active pickups are switched to passive mode to eliminate any unwanted noise or buzzing. This direct input, or D.I., may then go direct through any sort of compression or processing you’d like and then to whatever recording medium you choose to use.

Next, run a line out of the direct box to your bass amp (see pic 5). Right against the speaker itself, an AKG D-112 or Shure Beta 52 is used to capture a lot of the low end coming from the speaker. Approximately six feet in front of the cabinet, place a large diaphragm condenser mic, like a Rode NT2 or ADK A51sTC, directly in line with the center of the cabinet (see pic 6). This mic will help catch a lot of the grittiness of the actual amp and, when mixed properly, will help to add some liveliness to the bass track. You may need to check the phasing of these three tracks, using some phase reversal or going into your DAW to actually align the two mic tracks with the attack of the transients in the D.I. track. Now, experiment with the balance of these three sources to get the perfect bass sound.

Use these suggestions as a springboard for your own creativity. There are many other options for getting great recorded amp sounds. These are just a few that can serve as the foundation for most any recording project.