What follows is the result of a few days messing around with different microphones in various different positions, in an attempt to ‘master’ certain techniques and invent a few of my own. I recorded three different instruments during this time, using three different techniques for each, to see which sounded the best. The three instruments I recorded were the Harmonica, Mandolin and Guitar.
GUITAR
AB STEREO PAIR.
I used two Octava MK-12 microphones with omni directional heads attached to record this. Setting the mics up on a stereo bar I placed them on a mic stand so that they faced the guitarist, and the distance between the mics and guitar was about 40cm. I angled the mics so that they aimed slightly above the hole in the guitar’s body. This was in effect to EQ the sound slightly. I found that by pointing the mics directly at the body of the guitar the sound was much bassier. By angling them by approximately 10 degrees, a significant difference in bass level could be heard to the benefit of the recording. The result was an extremely warm sounding guitar, without too much room sound interfering. The recording sounded very well balanced, with the high and low frequencies of equal measure. This is the best of the three guitar recordings in my opinion.
AB STEREO CARDIOID PAIR.
As the sound from the standard AB pair was very nice, I decided to try the same set up, only swap the omni-directional heads for cardioid ones to see how much of a difference it would make. Initially, the sound was nowhere near as good, so I needed to move the microphones. After crawling around the studio for a while I decided that the best sound from the guitar seemed to be located just underneath its body, thus I set up the cardioid pair in this position. Raised about 25cm from the floor and again angled upwards by about 10 degrees, the mics were positioned facing the wall just behind the guitarist. The recording of this is still fairly warm, although perhaps just a little bassier than the standard AB pair. The sound was quite clear still although as the mics were facing the wall behnd the guitarist, the guitar sounds a little more distant.
EXPERIMENT: OCT HYBRID.
I wanted to add a third microphone to the equation to see whether or not it would pick up more of the rooms natural reverb, so I decided to try an OCT set up with two Hyper-cardioid Octava MK-12 outside mics, and a Rode NT-1A cardioid forward facing mic. I initially set up the OCT triangle wrong however, believing that the distance between each outside microphone and the central microphone to be of equal distance between 40-90cm and so my resulting triangle had a width of 130cm; too wide for an OCT set up. This did sound pretty good though, so I decided to keep the distances larger, and play with the triangle a little more. I raised the forward facing microphone by approximately 15cm. This made it closer to the guitar and so it would get a stronger signal. The outside microphones thus were mainly picking up the reflections from the room rather than the direct sound of the guitar. The result was a recording that featured a nice amount of reverb from the room, and the guitar still sounding fairly warm. I think that this recording was warmer than the one captured by the cardioid pair, however I think that the cardioid recording seems warmer at first because of the decreased amount of reverb.
MANDOLIN
AB STEREO PAIR.
I decided here as with the guitar, to face the microphones towards the instrument. Raised approximatey 130cm from the ground and angled downwards by 45 degrees, I placed the mics to the side of the mandolin, as this was the area in which the instrument sounded loudest. I also wanted to pick up as much resonance from the instrument as possible, so I needed the mics fairly close to the body of the mandolin. The recording was very clean, and also very warm, but there is almost no natural reverb from the room. I feel that the full range of frequencies from the instrument were received by the mics but at the same time the sound of the pick being used to strum is not intrusive on the sound. This is the best I feel of the three mandolin recordings.
AB CARDIOID STEREO PAIR.
Based on the AB Stereo technique with omni-directional mics, I set up two Octava MK-12 mics with cardioid heads on a stereo bar in the same way. Making the mandolinist stand, I positioned the microphones so that they faced the instrument again, only this time angling them towards the floor on a slope of approx. 45 degrees. In the room I had noticed that the low frequencies of the instrument seemed to be louder beneath it and thus the cardioid mics would pick this up more effectively by facing downwards. However, by being at an angle they would still pick up the sounds from above and so the signal should be fairly balanced, especially as the Mandolins natural resonance leans toward the higher frequencies anyway. The resulting sound was fairly clean, although there was definitely a small amount of reverb caused by the room and the sound of the pick being used to strum chords is heard quite clearly.
DECCA TREE.
I wanted to recreate the room sound of the cardioid pair, but wanted a warmer result. I set up a DECCA tree triangle, using two omni-directional Octava mics at the back, and a Rode NT-1A cardioid mic as a forward facing mic. The Rode mic sat one metre infront of the back mics, which in turn were one metre apart from the centre (see diagram).
I then got the mandolin player to stand about a metre from the forward facing cardioid mic. The theory here was that the forward mic would pick up the direct sound of the mandolin, and that the outside omni-directional mics would pick up the room sound. The final recording did have much more room sound than the cardioid stereo pair, and this makes the mandolin sound a little distant. It was warmer than the cardioid stereo pair however, and as with the standard AB pair the strumming of the strings wasn’t intrusive on the sound.
HARMONICA
AB STEREO PAIR.
I set up two Octava MK-12 omni mics on a stereo bar, raised about one metre from the floor infront of a chair. The harmonica player then sat on the chair and leaned forward so that the harmonica was 30-40cm from the mics. Due to the closeness to the microphones and the loudness of the harmonica I had to turn the input levels down somewhat to stop it from clipping. The resulting audio was very warm, and I feel captured the ‘soul’ of the harmonica well. It was a very crisp recording, featuring very little room sound, probably because the mic was positioned not only low down in the room, but so close to the harmonica as well.
NOS STEREO
Using the Octava mics again, this time with cardioid heads, I set them up, again, about one metre from the floor facing forward at 90 degrees to each other with the heads 30cm apart. I got the player to stand behind the microphones this time however so that the resulting sound would be made up of mainly the reflection of the sound from the surrounding wall. Because of the NOS set up both the cardioid microphones were both pointing towards corners of the room. The resulting sound had a little more distance in it than the standard AB pair and was quite crisp, but was not as warm. This was probably due to the low frequencies being absorbed into the walls before the microphones could pick them up.
EXPERIMENT: RAISED FULLY CARDIOID DECCA TREE
I wanted to regain the warmth of the AB pair, but increase the room sound in this experiment. I set up three cardioid microphones (two Octavas and one Rode) all facing outwards. The forward facing Rode mic being one metre infront of the two outwards facing Octava mics which were seperated by two metres. To pick up as much of the room sound as possible I raised the mics two metres from the ground. I then got the harmonica player to stand in the centre of the triangle, the theory being that each mic would pick up part of the sound as it travelled past, but then would each get a unique reflection of the sound on the way back. Because they were all cardioid mics, they shouldn’t pick up anything from the other’s part of the room. I was satisfied with the fullness of the recording, which featured much more reverb than the NOS set up. Also the recording I felt had gained back the warmth it previously had had. I think this was the best of the three harmonica recordings.
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