Topic: dpa 4011 for mid side

[DCaswellUK]

Hi,
I was doing some experimenting using the dpa 4011 and schoeps mk8 as a mid side pair, but was unable to get a decent result. If someone could advise as to whether these mics do not pair very well, or maybe it was just user error!!?  The schoeps has a hotter output that the dpa, does this mean that the levels of the mics need to be adjusted accordingly? At the same time I tried a pairing of the neumann km84 with the mk8 and this sounded much better...Is there a different side mic that pairs better with the dpa? I really like this mic for my classical guitar, having tried many and various mics...at the distance that I prefer, which is about 1/2 metre, this mic seems the most suited..the km84 is also very nice, but for me the dpa is the best so far.
Thanks to anyone who might be able to help with this.
Kind regards,
David Caswell

[stevetoney]

I don't know about how these two mics pair soundwise, but you do need to get the levels on your two tracks adjusted for mid-side to work for you.  Since this apparently didn't happen at the recording stage, you'd need to do this in post.  I do seem to remember reading here on ts.com that Schoeps have a different sensitivity than DPA.

FWIW, when mixing in post, I usually start with the levels fairly equal on both the mid and side channels and then I tweak to taste from there. 

I'll often opt to have the side levels a bit lower than the mid, usually because the sound from the mid mic is direct and, in my experience anyway, tends to be the higher quality sound source of the two.  The side channel is often pointing at the walls and sometimes the sound quality isn't quite as good since there's a higher percentage of reverberant sound from that direction.  Obviously that will influence the stereo image though, so that's why I say mix to taste. 

If both channels sound fantastic, then I'll concentrate more specifically on the stereo imaging through tweaks of the side channel levels.

[acidjack]

^^^ I have both the CMC6x series Schoeps and DPA 402x, and yes, the Schoeps are WAY hotter mics than the DPA (I assume this is also true of the 4011.

On the R-44, I have to turn the dial down a full "click" on the Schoeps to make the levels of the two even, which I believe is a +2dB difference.

[DSatz]

You can use any two microphones for M/S as long as they both work and the "S" microphone is a figure-8. Their sensitivities don't need to be the same, but you need to regulate the gain (amplification) somewhere before you matrix from the M and S signals into stereo left and right so that you're in control of the proportions in the mixture. That's true whether you're using microphones of different sensitivity or not. Of course a less sensitive microphone would generally need to have more gain applied. But controlling the relative levels of the M and S signals going into the matrix (or alternatively, controlling their gains within the matrix) is essential as a way to vary the stereo effect to your liking, no matter what the sensitivities of the two microphones are. If you simply accept whatever your particular microphones give you as the relative level of S signal to M signal, you'll miss out on much of the value of this technique.

More S signal (relative to the M signal) means a wider-seeming stereo image and more reverberant sound. Less S gives more clarity and a stronger center, but less spaciousness and depth. The more you decrease the proportion of S, the more you approach a mono recording with the M signal alone going to both playback channels. However, too much S leads to a vague and "phasey" sound--it has little or no center and not enough direct sound.

If you have an S microphone that's far more sensitive than your M microphone and you don't compensate for that fact, your stereo playback will sound distant and "phasey" because there won't be much direct sound from the front-facing microphone. Due to the basic nature of figure-8s, with front and rear lobes in opposite polarity, most of the signal in each speaker will simply be the inverse of the signal in the other speaker. It'd be very much like listening to a bad mono recording--one in which the engineer's aim had been off by 90 degrees--through a playback system that has one loudspeaker wired "out of phase" (in inverse polarity).

Simply setting up M and S microphones without making any arrangement to regulate the individual gain levels of those two channels, and waiting to see what the combination happens to give you, isn't likely to give highly satisfactory results. Even if the sensitivities of the two microphones are spot-on identical (which would be rare even if they came from the same manufacturer), the proportion of M to S that gives the results that you like best will generally differ from recording to recording, and can only be found by varying it and listening to the result.

--best regards

P.S.: Clicks on the R-44 are mostly 6 dB, though if I recall correctly there's an exception somewhere along the route.

[DCaswellUK]

Thank-you very much for the responses to my post. I think that part of my confusion is between the two 'adjustable' parameters that is to say gain and spread, and if David Satz could comment on this then I'd be grateful. My understanding was that a good starting place for this technique was to set the gain of the mid mic, and then to set the gain of side mic at the same level or slightly less. Then in the matrix the spread of the side is set to the desired amount.
Could you say what the result would be if:
the inital gain of the side mic is very high, but the spread chosen in the matrix is only a small amount of side, or conversely, if the inital gain of the side mic is low but the spread chosen in the matrix is high.
I notice that some of the matrix boxes, such as the sonic orbit, have no 'spread' control at all, and only rely on the levels to make the blend of the two mics? Also apparent is that the levels of the final 'xy' mix are quite low, despite the fact that a good level has been set for the mics in the original 'ms'. Do some of the 'outboard' matrix boxes boost the levels of the final xy?
Finally is ms considered a good technique to use on a single acoustic guitar? My understanding was that the array needs to be placed in the middle of the source, which for guitar means aiming the mid mic around the area of the soundhole...
I would be grateful for any advice that you can offer, which will surely be of benefit to any other novices such as myself in understanding this difficult technique.
Kind regards,
David Caswell

[goodcooker]

Finally is ms considered a good technique to use on a single acoustic guitar? My understanding was that the array needs to be placed in the middle of the source, which for guitar means aiming the mid mic around the area of the soundhole...

I think the idea with stereo recording an acoustic guitar is to capture the two distinct sounds that it makes - the mellower sound of the top vibrating + the sound coming from the sound hole (along with any percussive sounds of the picking hand) and the brighter sounds of the strings against the fretboard. The string is vibrating on both ends so the sound coming from each "side" of a stereo track will sound different. I have found that those two sounds aren't necessarily best mixed right/left but it depends on what you are mixing it with (other instrumentation/voice) and the sound you're shooting for in the end.

That being said I did use M/S for acoustic guitar for some fingerpicking background tracks from about 2 feet away and it came out really nice. I used a Peluso CMC6-cardioid cap and an ADK TL in Fig8 and ran through a really punchy preamp. I pointed it at the top between the soundhole and the fingerboard.

You might be better served using a more mellow/less bright mic for the mid source. The DPA 4011 is extremely accurate and revealing and some would say bright to use on acoustic guitar.

One of my favorite techniques was to put a small diaphragm cardioid condenser in front of the soundhole and an omni pointed straight down at the bridge next to my right ear. Real mellow sounding for strummed and picked stuff...and mandolin.

[Rob D.]

You can use any two microphones for M/S as long as they both work and the "S" microphone is a figure-8. Their sensitivities don't need to be the same, but you need to regulate the gain (amplification) somewhere before you matrix from the M and S signals into stereo left and right so that you're in control of the proportions in the mixture. That's true whether you're using microphones of different sensitivity or not. Of course a less sensitive microphone would generally need to have more gain applied. But controlling the relative levels of the M and S signals going into the matrix (or alternatively, controlling their gains within the matrix) is essential as a way to vary the stereo effect to your liking, no matter what the sensitivities of the two microphones are. If you simply accept whatever your particular microphones give you as the relative level of S signal to M signal, you'll miss out on much of the value of this technique.

More S signal (relative to the M signal) means a wider-seeming stereo image and more reverberant sound. Less S gives more clarity and a stronger center, but less spaciousness and depth. The more you decrease the proportion of S, the more you approach a mono recording with the M signal alone going to both playback channels. However, too much S leads to a vague and "phasey" sound--it has little or no center and not enough direct sound.

If you have an S microphone that's far more sensitive than your M microphone and you don't compensate for that fact, your stereo playback will sound distant and "phasey" because there won't be much direct sound from the front-facing microphone. Due to the basic nature of figure-8s, with front and rear lobes in opposite polarity, most of the signal in each speaker will simply be the inverse of the signal in the other speaker. It'd be very much like listening to a bad mono recording--one in which the engineer's aim had been off by 90 degrees--through a playback system that has one loudspeaker wired "out of phase" (in inverse polarity).

Simply setting up M and S microphones without making any arrangement to regulate the individual gain levels of those two channels, and waiting to see what the combination happens to give you, isn't likely to give highly satisfactory results. Even if the sensitivities of the two microphones are spot-on identical (which would be rare even if they came from the same manufacturer), the proportion of M to S that gives the results that you like best will generally differ from recording to recording, and can only be found by varying it and listening to the result.

--best regards

P.S.: Clicks on the R-44 are mostly 6 dB, though if I recall correctly there's an exception somewhere along the route.

Thanks for the great info DSATZ. Coming from someone who recently purchased and AK20, I've been soaking up all this type of info. Very helpful!