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Recording classical guitar in mono?

I'm getting ready to record a classical guitarist in my studio. There will be no other instruments; only his guitar. I'm thinking I may record him in mono, and just wondered what you more experienced folks think about that... I've got three decent mics: two AKG C1000s and a Rode NT1-A.

Tonight I was experimenting with various mic setups while playing my own guitar (yikes!). I really like the sound of the Rode; it just seems warmer, especially when you get around 4 inches or so from the guitar. The AKGs sound very decent too. I liked them in an XY setup within three inches or so of the 12th fret. They also sounded good in an XY in front of the sound hole, but I'm worried that it will get too boomy. The spaced-pair setup (one above my right shoulder and one facing the 12th fret) also sounded pretty good.

Of course, I know that this will be a different musician with a different instrument, and I'll have to try out various mic placements until I find something that sounds good (and that will work with his playing). But I have the feeling the Rode will sound better on his instrument, too. I recorded myself with the Rode on a mono track and then inserted the SIR reverb (mono to stereo) on it, and it sounded pretty good! Listening to some classical guitar tracks on Pandora, I've noticed that while the sound is reverberant, it is pretty centered-- the tracks almost sound like they may have been recorded in mono...

Thoughts, suggestions?



TheJackAttack Sat, 10/29/2011 - 07:49

The AKG C1000 is really quite a brittle mic. One really has to watch that the mic is not pushed too hard and also that the high end hype is toned down. One of the mod guys does a rip roaring business in part from transforming the C1000 into better quality.

You can find an optimum location for a stereo pair by walking around the player, moving your head high and low until you find the spot that sounds best. The location might be unconventional but that doesn't matter. The room and the guitar are what dictate the mic position.

tunefoolery Sat, 10/29/2011 - 12:16

TheJackAttack, post: 378272 wrote: I doubt most were single mic recordings. Acoustic guitar has generally too complex a sound for single point mic technique.

I'm sure you're right. Still, however complex the sound may be, I'm not hearing a huge difference between the XY pos. and single mic, especially in terms of stereo spread. They're both pretty much at the center of the spectrum (I'm using Flux's Stereo Tool get a visual of the sound). Perhaps the two mics provide a little more depth...? I'd like to know technically what I'd be missing if I used just one mic.

And yes, I'm aware of the brightness of the C1000s... I always roll off the highs when recording.


RemyRAD Sat, 10/29/2011 - 12:50

There's another way to get a great sound on acoustic tar with a solid mono center image and that is MS (middle-side). And then you have your choice also of the width. And you can't do MS with your current supply of microphones without obtaining a figure of 8 microphone. And in a nice studio with real acoustics and real acoustical value, you get a beautiful sound. Of course you can mike in Mono and add synthetic stereo through reverb processors. We've all done that. I'd say with your current system and your client coming in, Give it that solid center image with the NT 1 Tight on the guitar, Mono, centered. Put your C. 1000s out a bit to scarf up some room sound. If your room sucks, move them in closer to the guitar. Hey one at the top and one at the bottom. But get that solid Mono centered image.

Okay okay, so I lied about the part about not being able to do MS with your current microphones. It's a little hard to get them into the correct positions as all 3 would have to be grouped very tightly together. The NT 1 A will be your front facing, toward the guitar, Middle. Now here's the tricky part. Your C-1 thousands must be placed back to back. In fact it would be better to duct tape them together back to back. Here's the trick. Both microphones combined together, in phase, both centered and panned to Mono equals an omnidirectional single microphone. If one microphone is phase inverted from the other microphone, phase cancellation creates a single figure of 8 microphone. But these two microphones must be phase inverted, combined together on a separate track before it can be considered for mixing together with the Mono middle. That's because the C. 1000's are acting like a single microphone together so they must be processed together independently from the mixing bus that will contain the middle Mono, both to be decoded utilizing your software matrix. I'm an MS nutcase. Not only with the microphones but a disease with a similar abbreviation. So there are different ways to utilize your 3 microphones in ways you never imagined. I mean to say 3 will get you 2 without any diminishing return.

I don't think my math was right?
Mx. Remy Ann David

tunefoolery Sat, 10/29/2011 - 21:19

Thanks for your suggestions, Remy. I did think of the MS configuration and actually tried it yesterday; it was a total failure since I really had no idea what I was doing.. :eek: It failed mainly because I tried to put everything on one track... :confused: This evening I realized that I may have a figure-8 mic; it's a Chinese knockoff that offers omni as well as a figure-8 setting, I think. I don't use it much because it's not on par with my other mics.. But I may give it a whirl to see how it performs in a M/S configuration... I'll have to see when I'm back in the studio on Monday.... If it doesn't work, I can attempt the MS with the two C1000s.... And if that doesn't produce good results, I'll try your initial suggestion. It will be fun to experiment with all this!

One question: I'd have to use the MS decoder in any case, whether I'm using the two C1000s or a single figure-8 mic, right?

I've recorded classical guitar previously, but didn't pay that much attention to where I was putting the mics... It seemed to turn out okay, except that the stereo image was not quite centered... You can hear that here: [[url=http://[/URL]="…"]KevinAyersGuitar's Channel - YouTube[/]="…"]KevinAyersGuitar's Channel - YouTube[/]

Anyway, thanks for the info, and sorry about your MS!

TheJackAttack Sat, 10/29/2011 - 21:42

If you use three microphones you will have three tracks. It is the manipulation of the side microphone(s) that give the stereo width and image. If you use two microphones for MS you will start with two tracks while recording but will copy and paste the side microphone to a third track and manipulate the pan and invert the polarity to create the missing audio information. It's less complicated than it sounds but don't try to record them all to one track. That just doesn't work at all.

hueseph Sat, 10/29/2011 - 22:39

Just from a guitarists point of view. Particularly with nylon strings, 4" is not enough space. Especially if you are using a coincident pair. I would say at the least a good two feet away. There's no point of using stereo technique when you are so close to the source. It may as well be mono. If you're going to use two mics at close proximity, you may as well try to capture from two points on the guitar, namely the body behind the bridge and where the fretboard meets the body. Somebody may rip this apart but it's just my point of view.

A good stereo recording really will depend on your room to sound decent.

BobRogers Sun, 10/30/2011 - 05:51

First, why are you putting the mics so close? Are you worried about recording at low levels? (-12dBfs is fine) Do you have very little gain from your preamps? (These are pretty high output mics if I recall. Most reasonable pres should be fine.) Is the room terrible? In my experience you won't get much of a stereo image 3" from the guitar (as you observed with the XY pair.)

I you try the MS techniques that Remy described, you don't need a decoder, and it might help you understand what is going on to do it yourself. But again, this often does not work well if the position is too close to the source.

1. MS with mid mic, cardioid pointed directly at the source (M) and coincident figure 8 side mic (S) pointed 90degrees from the mid mic (this puts the null pointed at the guitar.) Record two mono tracks. Duplicate the side track. Invert the second side track. Copy the original side track and the inverted side track to a stereo pair. As a check solo the stereo side track and listen to it in mono. (It should disappear.) Now mix the mono mid track and the stereo side track to taste.

2. MS with three coincident cardioids - one pointed a the source (M), one 90 degrees left (L), one 90 degrees right (R). Record all three mono tracks. Duplicate L and R and phase invert. Make one stereo track with L on the left and -L (the inverted L) on the right. Make another stereo track with R on the right and -R on the left. Bounce these two track (with faders at identical level) to a single stereo track. This gives a side track with L-R on the left and R-L on the right. Mix the mid and side as before. (You can skip the bounce and simply add the two stereo L/-L and -R/R tracks to the mid in equal measure if you want.)

tunefoolery Thu, 11/03/2011 - 14:13

Thank you Remy, TheJackAttack, Hueseph, and Bob Rogers for all the information and advice. I really really appreciate it! :smile: This forum is such a great resource -- better than a class! I'd love to try out the M/S configuration, but didn't really have time to do that this time... and my audio interface is not really set up for that (I'm embarrassed to say, I have only a stereo in, although I've found some workarounds to get more tracks coming in....). Thanks, Bob Rogers, for the very clear explanation of how to do M/S...

I ended up using the Rode in front (about a foot away or so) and the two AKGs about 2 feet above the left and right shoulders of the guitarist (and spaced about the length of the guitar), pointed down toward the guitar. The AKGs were angled down, but not straight down. The Akgs were recorded through the stereo in of my audio interface. The Rode was piped in through a Blue Icicle XLR to USB adapter. I know, it sounds lame, but it worked well!

I've found that the Rode provides a nice warm, intimate sound; the AKGs (with little to no EQ this time) provide a sense of space and depth. It's been fun trying various mixes with the "close" and "far" tracks. I've got lots of editing to do (lots of splicing because of performance mistakes.. ugh), but here's a quick mix I did of one track. I added the recording studio reverb from SIR2...:

[[url=http://[/URL]="…"]Sample guitar track by tunefoolery on SoundCloud - Create, record and share your sounds for free[/]="…"]Sample guitar track by tunefoolery on SoundCloud - Create, record and share your sounds for free[/]

With the added reverb, it still sounds like it's got a bit too much on the high frequencies; I'll probably play around with it some more. Suggestions / comments welcome. Thanks!