After Arriving at the Studio I started by setting up a microphone (AKG 414) in the middle of the Live Room, setting it to a cardioid polar pattern and placing a screen directly behind the guitar to help absorb any unwanted reflections returning to the front of the mic. I set up all the necessary functions on the desk including adjusting gain and arming Pro Tools to record.
I made a conscious decision not to add any E.Q. or effects to the signal, as I wanted the best possible natural sound. This would help me later in the process as it would involve less tweaking to the sound, which ultimately saves time, resources and provides a tone more consistent with an unrefined Parlour guitar.
I decided to set up a three different mic placements that I would apply to both the live and dead room. This would provide me with a controlled experiment so I could accurately compare the two environments and mic placements. Let’s begin with the live room recordings…
The first placement was at the 12th Fret, 30cm away:
At first listen, the recording sounds very clear and you can tell the microphone has picked up a slight room ambience, which suits the guitar nicely. However, upon further inspection I noticed that the recording was slightly too boomy. This will be due to the closeness of the microphone to the sound hole, even though it is not directly in front of it. As White (1999) suggests,
‘When working with instruments such as guitars that have soundholes, try not to aim the mic directly at the soundhole – it may produce a seductively large signal, but it is likely to be too boomy and coloured… All cardioid-pattern mics exhibit a proximity effect, which means they produce more bass when used very close to the sound source.’
Proximity effect, or ‘bass tip up’ is described as an,
‘Increase in low frequency response which occurs at distances less than about 1 metre from the pressure gradient operated microphones’ (Borwick, 1980)
‘Distortion caused by the use of ports to create directional polar pickup patterns… Depending on the mic design, proximity effect may easily result in a boost of up to 16 dB, usually focused below 100 Hz.’ (Sweetwater 1997)
Due to the increased bass presence from the proximity effect, I deemed the recording technique as unsuitable for my E.P.
(Further information on Proximity effect can be found here) – Why Does Proximity Effect Occur
The second technique used was at the 12th Fret, 60cm away:
This method proved to be highly effective and it reduced the proximity effect considerably, however listening back I feel with no effects it is still slightly too bass heavy and the recording sounds a little ‘boxy’. The chances are that the microphone was either pointing slightly closer to the lower strings on the guitar or it was still picking up too much of the soundhole. However this technique still produced far better results than from 30cm away.
Finally the third was also on the 12th Fret, but 1 metre away:
This recording has the greatest room ambience, as you might expect but it also features a considerable amount of bass as well. Looking back it would have been a better suited to place the microphone slightly further up the neck to capture more detail. Why was the microphone picking up so much bass despite being much further away? It wasn’t the proximity effect as the mic was too far away. After further in depth research I discovered the cause. Diffraction.
Borwick, J. (1980) Sound Recording Practice. Oxford University Press.
Sound On Sound (1999) Using Microphones – Frequently Asked Questions [online] Sound On Sound, Available from http://www.soundonsound.com/sos/aug99/articles/micfaq.htm [Accessed 20 February 2015].
Sengpiel Audio, Why Does Proximity Effect Occur [online] Sengpiel Audio, Available from http://www.sengpielaudio.com/WhyDoesProximityEffectOccur.pdf [Accessed 20 February 2015]
Sweetwater, What is Proximity Effect? [online] Sweetwater, Available from http://www.sweetwater.com/insync/proximity-effect/ [Accessed 20 February 2015]