Topic: Please try & explain.

[SAnthony]

Hello,

I know this might sound dumb but can someone try & explain to me how a stereo shotgun mic would sound different to a normal single point stereo mic.

[DSatz]

A stereo shotgun microphone is just a kind of one-point stereo mike. Specifically it uses M/S, with the shotgun as the "M" microphone. And at low and mid frequencies the shutgun doesn't have any special directional properties, either. Shotguns function as ordinary directional microphones until you get above 2 - 3 kHz.

Above that point, the slotted tube which is in front of the capsule (that's right, the capsule isn't at the tip of the microphone--it's near the back!) begins to set up a somewhat irregular pattern of partial cancellations for high-frequency sound coming from the sides of the microphone. Consonants from speech or singing fall into this frequency range, so this characteristic can be useful for making speech pickup more intelligible when you have to record from a somewhat greater distance than would otherwise be optimal.

That's the situation that film and video sound recordists often find themselves in, since the microphone has to be kept out of the camera frame. However, any knowledgeable film or video sound recordist would instantly set the shotgun aside and use a good supercardioid or cardioid if they could conceal it in the scenery instead; shotguns are troublesome to handle (unless you're in a set scene where the talent always stays on axis) and usually are a distinct compromise as far as sound quality is concerned.

Music recording with shotgun microphones is a last resort since their directional response is so irregular and their frequency response even on axis tends not to be very smooth, except perhaps in the very best of certain models that have come onto the market in recent years (price range ca. $2000 each). For years, film sound was dominated by two particular models that managed to sound both dull and spitty at the same time, and that you had to keep zeroed in on the talent because their off-axis pickup sounded so different from their on-axis pickup.

M/S recording of music with a shotgun for "M" may be only a compromise, but at least it's better than trying to do X/Y or other stereo recording with two shotguns!

--best regards

[Javier Cinakowski]

Another terrific post by DSatz!  You derserve the taperssection member of the year!

but at least it's better than trying to do X/Y or other stereo recording with two shotguns

I have a question regarding the recording of music with two shotguns...  Perhaps you could help?

I have been following the "Stereophonic Zoom" technique.  I even made one of those goofy "gator/sextant" gadgets to measure the recording angle.  The paper by Williams does not include any information about angles for a shotgun microphone.

I understand that a pair of interference tube microphones is not ideal for field or studio recording of music.  That being said, in a large basketball arena, or from very far distance at a outdoor festival, I could see shotguns being advantagous.

My question is, is there an ideal placement/configuration or guidline in using two shotgun microphones from a distance?  Or should I just point and shoot.....

[DSatz]

Fred, there is no possible way to adapt Mike Williams' approach to a microphone whose polar pattern is so different at different frequencies. If you chose angles and spacings for one range of frequencies, they would be altogether wrong for other ranges and vice versa.

In all seriousness, no one that I know of recommends using a pair of shotgun microphones for stereophonic recording, period. If you want to use a shotgun as the "M" microphone of an M/S pair, that can make some sense; the shotgun's polar pattern may be irregular at high frequencies, but presumably it is at least laterally symmetrical, which is all that M/S requires. Though even there, you have to be careful since certain brands of shotgun microphone actually have a "this side up" as far as their pattern symmetry is concerned.

--best regards

[Javier Cinakowski]

Fred, there is no possible way to adapt Mike Williams' approach to a microphone whose polar pattern is so different at different frequencies. If you chose angles and spacings for one range of frequencies, they would be altogether wrong for other ranges and vice versa.

In all seriousness, no one that I know of recommends using a pair of shotgun microphones for stereophonic recording, period. If you want to use a shotgun as the "M" microphone of an M/S pair, that can make some sense; the shotgun's polar pattern may be irregular at high frequencies, but presumably it is at least laterally symmetrical, which is all that M/S requires. Though even there, you have to be careful since certain brands of shotgun microphone actually have a "this side up" as far as their pattern symmetry is concerned.

--best regards

That makes perfect sense.  I also understand that it is not recomended to use shotguns for sterophonic recordings.  The only thing that makes me think that shotguns from a distance are effictive is the Grateful Dead tapes that were done this way, with good results.

So being that the pattern is so irregular, I could see Williams technique to be impossible, but is there no good technique at all?   Point the mics toward the source and don't worry about spacing or angles becasue any adjustment there could be counterproductive?  That being siad, I would imagine that using the hyercard chart would yield better results than say the subcard chart...


Thanks!  T+
 

[Will_S]

Fred, there is no possible way to adapt Mike Williams' approach to a microphone whose polar pattern is so different at different frequencies. If you chose angles and spacings for one range of frequencies, they would be altogether wrong for other ranges and vice versa.

In all seriousness, no one that I know of recommends using a pair of shotgun microphones for stereophonic recording, period. If you want to use a shotgun as the "M" microphone of an M/S pair, that can make some sense; the shotgun's polar pattern may be irregular at high frequencies, but presumably it is at least laterally symmetrical, which is all that M/S requires. Though even there, you have to be careful since certain brands of shotgun microphone actually have a "this side up" as far as their pattern symmetry is concerned.

--best regards

That makes perfect sense.  I also understand that it is not recomended to use shotguns for sterophonic recordings.  The only thing that makes me think that shotguns from a distance are effictive is the Grateful Dead tapes that were done this way, with good results.

So being that the pattern is so irregular, I could see Williams technique to be impossible, but is there no good technique at all?   Point the mics toward the source and don't worry about spacing or angles becasue any adjustment there could be counterproductive?  That being siad, I would imagine that using the hyercard chart would yield better results than say the subcard chart...


Thanks!  T+
 

Rule of thumb in the GD days was aiming each shotgun at the outsides of the respective PA stacks.  With the capsules 8-12" apart.  The idea then is that the left signal is dominated by the left side of the PA, and the right signal by the right side of the PA.  Not a real stereo image (in particular, the audience and room don't seem to be arrayed in front of you) but if instruments were panned a bit left/right in the PA mix, they will also be panned a bit in the recording.  The spacing introduces a little phasieness/timing difference to the recording that again isn't faithfully recreating a stereo image, but does make things seem less mono.

Edit:  And yes, I think trying to apply the stereophonic zoom technique with shotguns would result in poor sound.  Being distant from the source, you'd want a small stereo recording angle = wide angle bewteen mics.  Shotguns aimed at nothing in particular (or worse, the walls) won't sound good.

[SAnthony]

Cheers guys, interesting info.