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Author Topic: Schoeps MK41 Hypercardioids- Unpleasant Off Axis Response?  (Read 5658 times)

Bob Schwenkler

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i know there are at least a couple people here that use the schoeps mk41 capsule heads here. i bought a pair recently and wanted to get some more experienced feedback on what i am hearing. i am using the cmc6 amplifiers with the caps.

in my use thus far, i have found the off axis response of these mics to be somewhat unpleasing(see below). with some mics, this discovery may should not be surprising, as many mics have pretty nasty off axis. but one of the things that drew me to these mics was testimonials of its performance in this area (i bought used from across the country with no chance to demo).

the experiences where i have noticed this have been when using these mics in coincident or near coincident configuration to record live guitar and singing. in one case i used the schoeps as guitar mics and angled them downward to take advantage of their  off axis rejection. i also had a vocal mic placed. in another instance i used the pair in a near coincident config. with about a 110deg. angle between them (i read about it in a book and thought i would give it a shot). as you can perhaps tell from my descriptions, the off axis source was significantly off axis (~60-90 deg). the coloration simply sounded thin, harsh, and generally unpleasing.

these mics sound beautiful on axis, and i have not yet experimented with sources at more "easy" off axis angles (lets say ~10-45 deg.)

the only reason i ask here for feedback instead of just learning myself is because i would like, if possible, to not have to discover these unpleasant mic characteristics during or especially after sessions.

do the cardioid, subcardioid, and omni caps exhibit any of this behavior?

any comments are very welcome.

Mike Mermagen

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Re: shoeps hyperc- unpleasing off axis response?
« Reply #1 on: May 18, 2005, 03:19:41 pm »

Bob,
In my experience, if the capsule is used for close miking or in a studio, then "on axis" is better and you can take advantage of the proximity effect (bass boost) due to the close placement as well. If you point the capsule in a direction to have the source "off axis", you mustn't forget that there still is an "on axis" and where that is pointing and what sounds that might be capturing.

In ambient recording venues, the microphone can be placed fairly far from a sound source. In a given hall, if I'm placing my omnidirectional mics at a distance of 8-10 ft, my cardioids may be 15-20ft, and the hypers perhaps 20-25ft away from the source (for the sake of argument). Some people use them as spot or sweetening mics to focus more attention on a particular instrument and place them closer.

I would say, if your intention was not to achieve great clarity or use them as prescribed above, then it may not be what you are looking for.

Mike
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David Satz

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Re: Schoeps hyperc- unpleasing off axis response?
« Reply #2 on: May 18, 2005, 03:40:29 pm »

chikkenguy, a 110-degree angle for two near-coincident cardioids normally gives a solid stereo image across a nice, wide stereo pickup angle. With 17 cm spacing between the capsules, that's well known as the "ORTF" stereo pickup method, and I'd guess that this is what your book was talking about. But given the narrower pattern of supercardioids, the angle between microphones needs to be narrower as well.

The Schoeps MK 41 is actually somewhere between a super- and a hypercardioid, so this difference is really significant. With the setup you described, you were "starving" the center of the stereo image and you also were most likely aiming the null of both capsules at some part of the direct sound source. That's generally not a good thing to do with any directional microphone.

In general, the closer a microphone's pattern is to a figure-8 (pure pressure gradient), the more nearly that microphone's off-axis response will sound like its on-axis response--though of course the off-axis response will be weaker because of the directional pattern itself.

In case that was obscure, let me say it another way. With a good figure-8 microphone, the frequency response can be essentially the same at all angles, except for right around the null at 90 degrees; the sensitivity, however, will vary greatly at different angles of sound incidence. Meanwhile the opposite behavior occurs at the opposite end of the pattern spectrum, with single-diaphragm omnidirectional microphones (pressure transducers): Their sensitivity (say, at 1 kHz) will be the same at all angles of incidence, but if the microphone is of the normal size as used in studios, its on-axis response will be quite different from its off-axis response in some range of high frequencies.

Since the Schoeps MK 41 is closer to a figure-8 than a cardioid is (i.e. it has a greater proportion of pressure gradient response as opposed to pressure response), the off-axis response of the capsule is closer to flat than that of a comparable cardioid such as the MK 4. Does that make sense, I hope?

--best regards
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Bob Schwenkler

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Re: shoeps hyperc- unpleasing off axis response?
« Reply #3 on: May 18, 2005, 04:51:01 pm »

Quote:

110-degree angle for two near-coincident cardioids normally gives a solid stereo image across a nice, wide stereo pickup angle. With 17 cm spacing between the capsules, that's well known as the "ORTF" stereo pickup method, and I'd guess that this is what your book was talking about


the configuration i read about was actually a coincident method. i forget the exact title of the book. perhaps i should go review what i read to make sure i am remembering correctly.

Quote:

In my experience, if the capsule is used for close miking or in a studio, then "on axis" is better and you can take advantage of the proximity effect (bass boost) due to the close placement as well. If you point the capsule in a direction to have the source "off axis", you mustn't forget that there still is an "on axis" and where that is pointing and what sounds that might be capturing


i am aware of proximity effect during my sessions (and outside of them as well, i suppose), especially when close micing. i will re-describe one of the situations i wrote about above for clarity's sake, as i may not have explained it well enough. i was using the pair of schoeps to capture an acoustic guitar while using one more mic (ld condenser) to capture the voice. my intention was to use the area of less sensitivity of the schoeps in such a way that it would somewhat reject the voice while capturing the guitar. it was less sensitive to the voice, but the timbre of what was still captured was quite unpleasing, and affected the overall timbre of the vocal sound negatively.

perhaps my experiences will not quite align with other peoples' and maybe only i will ever hear what i am hearing, but i suspect that someone else might be able to give me some insight or advice. i welcome more comments. one thing is certain though, i will have to experiment more with this to get a better idea of the situation.

Bob Schwenkler

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Re: shoeps hyperc- unpleasing off axis response?
« Reply #4 on: May 18, 2005, 04:59:53 pm »

one more thing:

Quote:

and you also were most likely aiming the null of both capsules at some part of the direct sound source. That's generally not a good thing to do with any directional microphone.



i think that what was happening to me is a similar situation to what you describe here. i was utilizing the null (or somewhere near the null) of the mic in an attempt to reject the voice. should i expect that most mics capturing a direct source in this fashion will generally produce an unpleasing result? i have not experimented at all with turning my mics around to actually see what the other end sounds like on direct sources.

one unrelated question: is there a way to enable email notification of replies in these forums? i have not been able to locate any such preference.

Yannick Willox

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Re: shoeps hyperc- unpleasing off axis response?
« Reply #5 on: May 19, 2005, 04:10:16 am »

chikkenguy wrote on Wed, 18 May 2005 22:59

i was utilizing the null (or somewhere near the null) of the mic in an attempt to reject the voice. should i expect that most mics capturing a direct source in this fashion will generally produce an unpleasing result?


I really love the Sennheiser MKH series for this. Coloration (off axis and even in the null) is very low.
Royer SF1 and SF12 are maybe even better in this regard.
If you aim an SF12 (two figure of eights at 90 deg) correctly, you can record two nearby sources (eg guitar and the guitarists voice) with amazing separation.
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Yannick Willox
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David Satz

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Re: Schoeps hyperc- unpleasing off axis response?
« Reply #6 on: May 19, 2005, 06:51:21 am »

Yannick and chikkenguy, the "null" of a directional microphone is never absolute, but the closest approximation will generally be found in good figure-8 microphones. That's a rather circular statement logically, since a fundamental aspect of a "good" microphone is consistent directional response across its frequency range. In any event, it's important to be realistic about the off-axis performance of directional microphones.

Keep in mind the spectrum of first-order directional patterns: omni <-> wide cardioid <-> cardioid <-> supercardioid <-> hypercardioid <-> figure-8. The closer you get to the figure-8 end of this spectrum, (all other things being equal) the more closely a microphone's off-axis response will resemble its on-axis response at both ends of the frequency range. In this case I think that the main problem is in the high frequency end of the range.

Here is a composite graph of the frequency response of a Schoeps MK 41 at certain characteristic angles of incidence. I would guess that this graph is 10 - 20 years old; in any case it certainly doesn't reflect Schoeps' current production, but it comes from a published source and shows the point that I want to make. So for better or worse here it is:

index.php/fa/1127/0/

Notice the response near the null angle of this capsule, labeled here as 123 degrees. The sharp, local ups and downs are room effects in most cases--the response isn't really as bad as it looks. We can talk another time about why that happens when you plot a graph like this one. But the point is, a "bathtub-shaped" response around the null angle is characteristic of all directional microphones. And cardioids are the worst offenders (the sound around the null is the least neutral) while good, small figure-8s are the best--the bottom of the "bathtub" is deeper, and the residue of sound which is picked up around the null angle (90 degrees) doesn't have the noticeable high frequency rise that any cardioid or supercardioid always has to some degree.

That's crucial for stereo imaging, and it is why a pair of supercardioid microphones must be angled somewhat more narrowly than cardioids would be--to avoid having the null of the left microphone aimed at the direct sound at the right of the stage and vice versa. I'd try 100 degrees as a starting point.

I'm personally convinced that the off-axis response characteristic is a strong reason for the attraction many classical engineers feel to Blumlein recording and ribbon microphones in many situations--the clean figure-8 pattern itself. But a good small condenser figure-8 microphone can very well have even better off-axis response than a bulky ribbon microphone and continue that clean pattern up to higher frequencies.

--best regards

P.S.: The graph shown in this message was published in a book of essays on microphones by the technical director of Schoeps, Mr. J
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Bob Schwenkler

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Re: shoeps hyperc- unpleasing off axis response?
« Reply #7 on: May 19, 2005, 09:28:13 am »

thanks for the information. i guess that i will have to keep learning these mics (of course). if i were to invest in the figure 8 caps for my schoeps, would it be reasonable to expect better off axis performance in situations similar to the ones i wrote about above?

David Satz

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Re: Schoeps hyperc- unpleasing off axis response?
« Reply #8 on: May 19, 2005, 10:28:24 am »

Bob, my real point is that supercardioid microphones are different enough from cardioids to deserve more experimentation and listening before you judge them. Give yourself more time, please.

"Cookbook" methods for coincident or near-coincident stereo recording that work well with cardioids will never work very well with other directional patterns unless you adjust the angles and/or distances accordingly. That's no reflection on the quality of the microphones. Objectively your MK 41s have smoother off-axis response than any cardioid I've ever seen or heard, but regardless, the pattern null of any directional microphone should never be aimed at strong, direct sound sources. The graph that I posted shows why that will cause the kind of problem that you got.

As far as figure-8s are concerned, while as I said I'm a big fan of using them where they work well, no one technique can ever be right for everything. Stereo pickups using figure-8s--normally crossed at 90 degrees--have some ideal properties, but they work only as long as whatever you're trying to record occupies 90 degrees of the space in front of the microphones or preferably a little less. And that's just too narrow for a lot of real-world recording situations. The mikes are as sensitive in back as they are in front, so by the time you move them to where they "capture" an orchestra, etc. within 90 degrees, often they're so far back that they're swamped with room sound and your recording will not be clear. A lot depends on the hall acoustics, and unfortunately not many venues are just right for that miking technique.

For me, since I am not the Lord of the universe in which the performances I record are taking place, that's the real advantage of supercardioids: with their somewhat wider front acceptance angle, a miking distance will more likely exist that still gives good clarity and balance in a situation like that.

--best regards
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Mike Mermagen

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Re: shoeps hyperc- unpleasing off axis response?
« Reply #9 on: May 19, 2005, 12:56:37 pm »

Bob,
I am curious what your working distance was when you were recording the guitar and listening to the voice, off axis. All of this comes into play when considering quality of sound off axis. This is also why I mentioned proximity effect. The directional mics can sound good when used very close and you get favorable prox. effect. But I don't think those effects occur behind the microphone and you can't consider that to be poor off axis response. If you place the microphones at the distance that they were designed to have a particularly even frequency response, you will notice that the off axis sound is just fine. But that distance will not be from 2 inches to 2 feet, but will be in the 10-30 feet range for the MK41. Therefore, you are using the MK41 in an "anything goes" technique, rather than a "cookbook" stereo miking technique.

Mike
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Bob Schwenkler

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Re: shoeps hyperc- unpleasing off axis response?
« Reply #10 on: May 19, 2005, 02:05:42 pm »

Quote:

I am curious what your working distance was when you were recording the guitar and listening to the voice, off axis. All of this comes into play when considering quality of sound off axis. This is also why I mentioned proximity effect. The directional mics can sound good when used very close and you get favorable prox. effect. But I don't think those effects occur behind the microphone and you can't consider that to be poor off axis response. If you place the microphones at the distance that they were designed to have a particularly even frequency response, you will notice that the off axis sound is just fine. But that distance will not be from 2 inches to 2 feet, but will be in the 10-30 feet range for the MK41.


in the close mic situations, the distance from the mouth to mic was probably in the neigborhood of 18-24" in most cases.

in one other case where i used the mics in a coincident array, they were about 4-5 ft from the source(s).

i noticed a similar coloration in both cases.

Quote:

upercardioid microphones are different enough from cardioids to deserve more experimentation and listening before you judge them. Give yourself more time, please.


i certainly plan on giving them more time. i just wanted to get some feedback from more experienced users.

an off topic question: at what distance do manufacturers usually test their mics' frequency response at? when i look at the graph for the mk41, what distance is that measurement made at?

ted nightshade

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Re: Schoeps MK41 Hypercardioids- Unpleasant Off Axis Response?
« Reply #11 on: May 20, 2005, 02:11:32 pm »

The area past the null is phase reversed and has a strange frequency balance- that's probably where your unpleasant off-axis sound is coming from. That's just too far off axis. The null trick works better with fig.8's, but it's still subject to phase issues which also come out pretty thin and tending towards the shrill.

I would start by recording the vocal and guitar into just one of the mk41's. You can use the directional boost on-axis to balance the guitar and the voice. You ought to be able to get this to sound quite nice.

Taking that whole picture into stereo is an ambitious enterprise. I'd like to hear about that.
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Ted Nightshade aka Cowan

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Bob Schwenkler

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Re: Schoeps MK41 Hypercardioids- Unpleasant Off Axis Response?
« Reply #12 on: May 20, 2005, 06:18:07 pm »

i did not angle the mics so far that they would be picking up sound from the out of phase region. when close micing, the source i was attempting to reject was at about 90 deg.

when attempting to capture the guitar in stereo, i have tried a few different things, most of them variations on coincident or near coincident configurations. they worked well aside from the off axis coloration of the voice...

ted nightshade

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Re: Schoeps MK41 Hypercardioids- Unpleasant Off Axis Response?
« Reply #13 on: May 21, 2005, 07:19:33 pm »

Things ought to sound very healthy at 90 degrees off axis, but I have had some strange vocal sounds from the mk41 even right on axis. Something about the capsule brought out a form of distortion on my voice on more than one occasion. It's also sounded wonderfully human on the same voice at a different time. I don't know an explanation for this, but it sounded like just the voice was distorting, not the acoustic guitar or percussion or anything else picked up by the same mic at the same time. This was well under the kind of SPL that would induce significant THD, but it sure did sound like THD. Maybe just a tiny amount of THD in a really noticeable "place"?

No explanation here, but I have heard some weird sounds on vocals with these mics. And some really nice sounds at other times.
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Bob Olhsson

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Re: Schoeps MK41 Hypercardioids- Unpleasant Off Axis Response?
« Reply #14 on: May 22, 2005, 03:08:44 pm »

In close miking applications it's best to point the null directly at what you don't want to pick up and follow the 3 to 1 rule. Otherwise you'll always have nasty comb filter effects even with utterly perfect patterns. I love co-incident miking but only 6 to 8 feet back from the source minimum.
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