"Where you listen" versus "Where you mic"

[Mike Senior]

Here's an interesting little methodological question for all you recording engineers out there. When miking up any instrument, it's a studio truism that you should listen for a good spot in the room before placing the mic. My question is this: assuming that you've found a spot for your head where you like the wet/dry balance you're hearing, what would be your miking distance relative to that head position in the following three cases:
[*] if you're using a single cardioid mic.
[*] if you're using a single omni mic.
[*] if you're using a coincident stereo pair of cardioids at (let's say) a 120-degree mutual angle.

(If you block one ear or cup you hands around them in any way to aid with these kinds of judgements, I'd be interested to hear about that too.)

For my own part, I usually like the sound of a single subcardioid where I'm standing, so a cardioid feels a bit dry and an omni a bit wet if I set them up at my preferred head position. The 120-degree XY pair usually works pretty well at head position for me. I've never had much luck with blocking an ear (it sounds distracting), so I don't do that.

[MGBR65]

I find that even when you have found a place where the balance seems right,I find it very difficult to guess where to put the microphone exactly.
What I now do is place the mic, put on my AKG K701 and put a delay of approx. 8 seconds on the signal and let the instrumentalist play, or play it myself, so then after a few seconds of delay I can hear exactly how it will record without also hearing the original signal.

MGB

[Hugh Robjohns]

I'm with you -- I can't get on with the blocked ear technique! Also, I agree that where it sounds good via ears is usually a bit too close for a cardioid spot mic, so that needs to go a bit further back, and a close omni usually need to be a bit closer. A stereo ORTF pair usually works if I place it where my ears were.

I like the idea of an 8 second delay on the headphones to separate live from recorded. Obvious and simple, but I've never heard of it being done before. Good tip.

Hugh

[Mike Senior]

I'm with you -- I can't get on with the blocked ear technique! Also, I agree that where it sounds good via ears is usually a bit too close for a cardioid spot mic, so that needs to go a bit further back, and a close omni usually need to be a bit closer. A stereo ORTF pair usually works if I place it where my ears were.

Glad to be in such exalted company! Thanks for the input Hugh.

I like the idea of an 8 second delay on the headphones to separate live from recorded. Obvious and simple, but I've never heard of it being done before. Good tip.

+1! This is a fantastic tip, and one I'd also never heard before. Maybe finally, I'll be able to do the headphone mic-positioning trick that I'v never been able to really use before -- the spill always used to put me off.

[Evie McCreevie]

... put a delay of approx. 8 seconds on the signal and let the instrumentalist play, or play it myself, so then after a few seconds of delay I can hear exactly how it will record without also hearing the original signal.

MGB

BRILLIANT! How come no-one's thought of or mentioned this before?

Is this a genuinely new idea? Should be standard practice from now on.

[John Willett]

... put a delay of approx. 8 seconds on the signal and let the instrumentalist play, or play it myself, so then after a few seconds of delay I can hear exactly how it will record without also hearing the original signal.

MGB

BRILLIANT! How come no-one's thought of or mentioned this before?

Is this a genuinely new idea? Should be standard practice from now on.

Well, this sort of thing used to be standard practice in the old days when we listened to an analogue recording off-tape as you had the delay between the record head and the replay head.

This method extends the delay to several seconds.

This could not be done, of course, until digital delay became affordable and high quality.

Great idea, though.

[Tomás Mulcahy]

Ha, yes I used to do that when mixing to a Revox B77 back in the day (because that thing had a "sound"!). Basically I'd start the mix that way, and after a while you'd have a good idea of what the tape was doing. Mostly HF loss. I assumed it was fairly standard practice. I asked a "big name" US mix engineer who's an analogue fanatic if he did it, I think he felt it was a dumb question. He'd just listen to the tape when he was finished and was "always happy" with what came back.

Great idea for mic positioning though. Incidentally 8 sec would be within the average for auditory memory. Sound engineers can be a lot longer although there isn't much research done on that.

[Hugh Robjohns]

Standard BBC practice was certainly to listen and check the sound off tape, and tweak the mix and processing accordingly, although for normal broadcast programming work you had to listen to the desk output to get the timings of fades right of course.

The eight (or whatever) second delay completely separates the monitored sound from the live performance, and so removes the spill issue very neatly, especially if the player performs in short stints! You couldn't do that with a quarter-second delay in off-tape monitoring.

H

[Tim Gillett]

Of course what might apply to a live mix and broadcast doesnt necessarily follow in a recording scenario.

We can record each instrument as dry as we like, and record room reverb on separate tracks. That is, we can capture everything, putting off the balancing choices until later.

Reverb is easy to add later, but very difficult if not impossible to reduce once it's already mixed in.

[Kwackman]

Of course what might apply to a live mix and broadcast doesnt necessarily follow in a recording scenario.

We can record each instrument as dry as we like, and record room reverb on separate tracks. That is, we can capture everything, putting off the balancing choices until later.

It's not only about dry & reverb sound though.
It's about placing a mic where it sounds good for the instrument.
Placing a mic to record an acoustic guitar, even in a dry room, takes a bit of experimenting to get a nice sound.

[Tim Gillett]

Of course what might apply to a live mix and broadcast doesnt necessarily follow in a recording scenario.

We can record each instrument as dry as we like, and record room reverb on separate tracks. That is, we can capture everything, putting off the balancing choices until later.

It's not only about dry & reverb sound though.
It's about placing a mic where it sounds good for the instrument.
Placing a mic to record an acoustic guitar, even in a dry room, takes a bit of experimenting to get a nice sound.

Sure, that's a given, but I take it Mike was talking specifically about the room acoustics wet/dry balance as it affects different mics such as omni, unidirectional, figure 8 etc..

Tim

[Guy Johnson]

A cracking thread, thanks guys!

[Phil Aitman]

Agreed this is a brilliant thread. Thanks for superb tips as always.

[Mike Senior]

It's not only about dry & reverb sound though.
It's about placing a mic where it sounds good for the instrument.
Placing a mic to record an acoustic guitar, even in a dry room, takes a bit of experimenting to get a nice sound.

Sure, that's a given, but I take it Mike was talking specifically about the room acoustics wet/dry balance as it affects different mics such as omni, unidirectional, figure 8 etc..

That's right. I agree that distance isn't just about wet/dry balance, though, which is why I'm intrigued as to how different people work around the fact that the position which sounds right with your ears from a wet/dry balance perspective isn't necessarily where you'll want to put the mic. It implies that you should listen for wet/dry balance first, then move your head to the distance you think you'll actually put the mic so that you can find a spot at that distance that also fits the bill on tonal grounds (trying to ignore that the wet/dry balance in that position will then sound wrong, of course).

[TheReson8or]

I think if you work with the same mics, in the same room with the same (ahem) ears....then you start to make choices almost instinctively...knowing (roughly) the parameters of each part of the chain. I have come to the conclusion that in a great environment, an omni mic placed close to your head ( in a good spot) is quite useful...that or a stereo spread. In fact I am experimenting more with omni pencil condensers! Dave

[benniferj]

Almost always let a guitarist bring up their ideal tone for a song before micing... then actually listen on axis to the cabinet and hear what's going on. They're normally shocked when I get them to listen with me how harsh they've made the tone actually coming out of the speaker and how different it sounds to what it does when they stand up and move away from it. Often a bit less gain and treble and it's unbelievably better at most mic positionings.

[Exalted Wombat]

Almost always let a guitarist bring up their ideal tone for a song before micing... then actually listen on axis to the cabinet and hear what's going on. They're normally shocked when I get them to listen with me how harsh they've made the tone actually coming out of the speaker and how different it sounds to what it does when they stand up and move away from it. Often a bit less gain and treble and it's unbelievably better at most mic positionings.

Yes, a lot of guitarists only know how their amp sounds when aimed at the back of their knees!

[Hugh Robjohns]

That's right. I agree that distance isn't just about wet/dry balance, though...

There is always the 'scientific approach' too, either to support the untuitive approach or to use instead of.

The Critical Distance measurement for the room tells you where the level of direct and reverberant signals are equal, and you would normally expect to need to place a cardioid mic a little closer than 50% of that distance for a 'good' sound quality. The directivity index of microphone polar patterns then tells you the ratio of relative distance from the source to achieve the same quality, and thus an Omni would need to be closer than 30% of the Dc.

Useful science in an unfamiliar room -- especially a very reverberant one like a church or cathedral!

H

[Richard Graham]

Interesting advice Hugh. How do you calculate the Critical Distance of a room then?