Comparing the three Schoeps MK2 caps

[PT6.7UZR]

I'm deciding which of these omni capsules to buy for my application.

The MK2 is ruler flat.
The S and H caps have a rise in high frequencies.
S starts near 3KHz.
H starts near 6KHz.

I'm recording classical piano and have a DAV BG1 2-channel pre, RME ADI 2 converters into Pro Tools.

The 9 foot piano is in a 425 sq ft room with 9 ft ceilings, hard lath and plaster walls, solid oak floors on a raised foundation, moveable heavy rugs and bookcases.
I expect the mics to end up between 3 and 7 feet from the open piano lid, which may put them closer to reflecting walls than the piano.

I don't know if this is near field or within what Schoep's catalog refers to as the reverberant radius, where "the direct frontal incident sound predominates over the reverberant sound of random angles of incidence".
Apparently this should influence your MK2 cap selection.

Which MK2 would be best for this ?

Edit: I'm already getting the sub-cardioid MK21s as my first pair.
I just need help deciding on which omni will be my second pair.

[MBishopSFX]

I'd use the MK-2 linear capsules for classical piano, the MK-2H for jazz.

I usually prefer to use mics other than Schoeps for piano, but you didn't ask about that.

[Arthur]

How does your piano sound in this particular room? Is it on the bright side or the dark one?

I own a BG2 and MK2 capsules. The DAV is a clear amp. If I had to guess, I'd say the MK2 should serve you well at this relatively close distance.

[PT6.7UZR]

Originally Posted by Arthur

How does your piano sound in this particular room? Is it on the bright side or the dark one?

That's hard to answer.
I own the piano and have my tech voice it so it is just the way I want it.
I would not say it is overly bright or dark.
If it was I'd throw some more money at my piano tech, rather than pic mics that compensate.

It is a new 9' 2" Bluethner, a German piano.
German/Italian/Austiran pianos are considered more clear and transparent than the thicker richer sound of Steinways or Mason and Hamlins.
The Bluethners are the warmest sounding of that European group.

I believe I want a mic that is just accurate, which is why I originally was going for the ruler-flat MK2.
But then I started reading how non-optimum acoustics can make a flat omni less desireable.
I read that if room reflections will be an signicant component (they arrive off axis where none of the MK2s are ruler-flat) the H and S may be preferred.

I just don't have the experience to know if this is the case in my situation, and if so would the H be better than the S.

[Arthur]

Originally Posted by PT6.7UZR

That's hard to answer.
I own the piano and have my tech voice it so it is just the way I want it.
I would not say it is overly bright or dark.
If it was I'd throw some more money at my piano tech, rather than pic mics that compensate.

This is a very sensible attitude. IF possible, you should have the same attitude with your room acoustics: since it's non optimum, why don't you try to better it before asking yourself which capsule will hide best its flaws?

If your room is not exclusively dedicated to music/recording, there are portable solutions (commercial and DIY) that can help you to tame your acoustics. Then, you'll be able to choose your capsules after artistic decisions, not out of frustration...

[ISedlacek]

If you plan to record rather close and in a relatively small room, MK2H and MK2S may slightly irritate you, since they have artificially boosted high frequency content. I record in a similar way and first I ordered MK2H long time ago(as my first Schoeps omni). I was so unhappy with it (too sharp) that I changed the pair within few days for MK2. And it has been perfect since then for me ...

[videoteque]

How much meters do you consider "close"?? Up to 3-4 meters??

When would you think of buying S or H in meters from musicians??

[ISedlacek]

Originally Posted by videoteque

How much meters do you consider "close"?? Up to 3-4 meters??

When would you think of buying S or H in meters from musicians??

As for me - I would prefer to have something neutral in all cases ... (and to add "air" later if needed)

[RobAnderson]

Critical distance changes with size/character of the room and the size of the ensemble. Using the S or H is not a matter of adding air, it is a matter of dealing with room acoustics and critical distance.

The MK2S is good for large ensemble recording where you are generally working near or at the diffuse-field boundary in a large space. It is a much more directional omni than the MK2 - it spotlights whatever is on axis. It also tends to give the strings a little more bite. The MK2 is a true omni - given the same placement, it will sound like it is further away from the source than an MK2H or an MK2S, and it exhibits a high frequency rolloff in the diffuse field.

If you are working in a small reflective room, you may be happier sticking with your MK21.

[PT6.7UZR]

Originally Posted by RobAnderson

. . . The MK2 is a true omni - given the same placement, it will sound like it is further away from the source than an MK2H or an MK2S, and it exhibits a high frequency rolloff in the diffuse field.

What explains this high frequency rolloff with distance?

Either:
1. The mic itself actually does have high-frequency rolloff that only occurs when used at a greater distance from the sound source. (How could this be?)

2. The mic's flatness does not change with distance. Rather the high frequency energy itself is more attenuated by distance than that of lower frequencies.

Or

3. It has something to do with that fact that reflected sound arrives off axis where even a flat omni's response has high frequency rolloff.

I suspect #3, but I wonder if there is any of #2.

I believe the off-axis response of the MK2S and H also have the same high frequency roll off as the MK2 - but their boosted high frequency response compensate for it when a lot of the acoustic energy is expected to arrvive off axis.
(Once the signal is vibrating the diaphram the mic no longer cares about what angle it came form.)

[Roland]

Rob's response is slightly missleading, in that the HF of the microphone doesn't change with distance, however the source sound's HF decays with distance due to the damping factor of the air (I think this was your answer no. 2).

Regards


Roland

[Jim vanBergen]

in all honesty, I'd rather have more MK2 capsules and use matched preamps with great stepped EQ if I need to add HF content. I'd be afraid to use the capsules when I'm NOT wanting that edge!

[RobAnderson]

Sorry - didn't mean to be unclear or misleading.

The high-frequency "rolloff" in the diffuse field is due to both #2 and #3.

The reason that omni's such as the MK2S or the KM130 have a high-frequency boost is generally to give them a flat frequency response in the diffuse field. It also makes them slightly more directional in nature since an omni capsule of that size generally has better high-frequency response on-axis. You can further "aggravate" this directionality using acoustic equalizers such as spheres.

I am not sure if you would get the same directional effect simply by using EQ. I am not saying you wouldn't - I simply don't know.

In general, the MK2 is a very nice sounding capsule with a very pleasant midrange. Under the right circumstances, it cannot be beat, but for my taste it must be in the direct field in a nice sounding room (which generally ends up being closer to the instrument/ensemble than you might think). Else, I would turn to a different mic. The MK2S has its place, but I think in general I slightly prefer the KM130's for a large-ensemble diffuse-field application (perhaps I just know them a little better since I have had them longer).

All in all, the MK21 has my vote as the most versatile and universally applicable of the MK2 series.

[pkautzsch]

Having used both MK2 and MK2S I can say that I prefer the S. That might be due to my setups usually being not really close but rather near the critical distance (outside of which actually the MK3 diffuse-field omni would be appropriate).
I might, if necessary, try to clarify some things about diffuse field and critical distance: A room's critical distance (the radius of the area around a sound source in which direct sound is louder than reverb) is largely determined by its size and by what walls/ceiling/floor are made of. If a room is large and has very reflective walls (e.g. concrete) it will usually have a long reverb - its critical distance will be smaller than that of a smaller room with lots of absorption. As long as the mic is significantly closer than the critical distance one can approximate it was in the "free field" (which basically says there are no reflexions). The more reflexions you get, the darker the sound will be - therefore you can raise the treble.

Originally Posted by RobAnderson

The reason that omni's such as the MK2S or the KM130 have a high-frequency boost is generally to give them a flat frequency response in the diffuse field. It also makes them slightly more directional in nature since an omni capsule of that size generally has better high-frequency response on-axis. You can further "aggravate" this directionality using acoustic equalizers such as spheres.

The difference between a "diffuse-field mic" and a "free-field mic" is ONLY equalisation inside the mic. The actually equalised mic is the free-field one, as the diffuse-field treble boost is due to diaphragm resonance (which, for the free-field version, is eq'd out).
In contrast to this, spheres like APE (DPA), SBK (Neumann) or KA (Schoeps) do acutally attenuate treble coming from behind the mic and boost treble coming from the front. They change not just the frequency response but also the pattern.

I am not sure if you would get the same directional effect simply by using EQ. I am not saying you wouldn't - I simply don't know.

You would get the diffuse-field equalisation effect by EQ, but not the sphere effect.

BTW I also prefer the Neumann AK30 cap as main omni pair. The Schoeps are nice, but rather as outriggers or room mics. Maybe they are too clean - Neumanns do add their sound, but it's a good colour and for me it's "the sound of a record". Don't like ultra-clean DPA either. Listening to loudspeakers isn't the same as sitting in the concert hall - but that's becoming a general rant now.

[Roland]

Originally Posted by pkautzsch

Having used both MK2 and MK2S I can say that I prefer the S. That might be due to my setups usually being not really close but rather near the critical distance (outside of which actually the MK3 diffuse-field omni would be appropriate).
I might, if necessary, try to clarify some things about diffuse field and critical distance: A room's critical distance (the radius of the area around a sound source in which direct sound is louder than reverb) is largely determined by its size and by what walls/ceiling/floor are made of.

Unless there is something absorbing the direct sound i.e. a boundry between the source and the microphone (or in fact a listener at that point), or the mic is directed off axis, the source will always be louder, using terms like "critical distance" is misleading.

If a room is large and has very reflective walls (e.g. concrete) it will usually have a long reverb - its critical distance will be smaller than that of a smaller room with lots of absorption. As long as the mic is significantly closer than the critical distance one can approximate it was in the "free field" (which basically says there are no reflexions). The more reflexions you get, the darker the sound will be - therefore you can raise the treble.

Again this confuses the issue, in small rooms the reverberation is often less than desirable usually either rendering them unsuitable or requiring close micing to negate the effects. Large rooms can be very reverberant, yet to a microphone even at reasonable distance, (say 4-5 metres back) the room can sound "dead". Other smaller "dead" sounding rooms, can appear amazingly lively when mics are opened up only a couple of metres from the source.

The difference between a "diffuse-field mic" and a "free-field mic" is ONLY equalisation inside the mic. The actually equalised mic is the free-field one, as the diffuse-field treble boost is due to diaphragm resonance (which, for the free-field version, is eq'd out).
In contrast to this, spheres like APE (DPA), SBK (Neumann) or KA (Schoeps) do acutally attenuate treble coming from behind the mic and boost treble coming from the front. They change not just the frequency response but also the pattern.

Some of these mics are "acoustically" equalized, DPA's are a good example, the spheres obviously "shade" the rear response, but they are also creating a boundry mic effect, albeit a spherical one!

You would get the diffuse-field equalisation effect by EQ, but not the sphere effect.

Amen!


Regards


Roland

[Roland]

I might, if necessary, try to clarify some things about diffuse field and critical distance: A room's critical distance (the radius of the area around a sound source in which direct sound is louder than reverb) is largely determined by its size and by what walls/ceiling/floor are made of. If a room is large and has very reflective walls (e.g. concrete) it will usually have a long reverb - its critical distance will be smaller than that of a smaller room with lots of absorption. As long as the mic is significantly closer than the critical distance one can approximate it was in the "free field" (which basically says there are no reflexions). The more reflexions you get, the darker the sound will be - therefore you can raise the treble.

Something I failed to add in the above post is that usually the manufacturers describe the addition of the HF equalization/lift as designed to compensate for "air damping". Obviously HF lift depending on what frequency it occurs at will have a "presence boost" effect, however assuming reasonable limits or pressure and humidity according to the makers own concept there would be specific ranges of distance at which the eq would compensate for the relative loss of hf due to distance. In real terms forgetting the obvious presence effect, at distances below the air damp factor critical distance, you would be likely to getting a load of additional hf not bargained for. I know of at least one major recording institution who use the "bright" grids on the DPA's irrespective of situation, they must just love that "hi-fi" sound!

Regards


Roland

[RobAnderson]

I think we still confuse the issue - though not for lack of trying!
Perhaps with a few more words we can reach the clarity we are striving for...

Let us start with defining the diffuse field. The diffuse field is that part of the sound field where the reflected sound energy is greater than the direct sound energy. The critical distance is the boundary where direct sound and diffuse sound energy are equal.

Roland: A room's critical distance (the radius of the area around a sound source in which direct sound is louder than reverb) is largely determined by its size and by what walls/ceiling/floor are made of.

This is another good way of putting it, but we begin to reach a slippery slope here:

If a room is large and has very reflective walls (e.g. concrete) it will usually have a long reverb - its critical distance will be smaller than that of a smaller room with lots of absorption.

True if we are talking about a smaller anechoic chamber, but in most real-life "smaller" rooms, the critical distance is actually much closer to the sound source than it would be in a large space where the wall boundaries are much further away - but I think we would all agree that this is so dependent on every individual situation.

HF of the microphone doesn't change with distance, however the source sound's HF decays with distance due to the damping factor of the air

This is absolutely true! Again, I feel the need to clarify that the HF damping you mention does not only imply the HF damping of the direct sound from the sound source with distance (which may actually be negligible depending on the circumstance), but is also from the HF damping of the reflections both as they spend their energy in the air and also (from a practical perspective) because they are generally being absorbed faster by the materials in the room. Whatever the cause, this damping results in less high-frequency content in the diffuse field than in the direct field.

But this is not the whole story of what happens to an omni in the diffuse field...

Attached to this post are the specs of the MK2 and MK2S capsules. The polar plots tell another part of the story. There is a "double-whammy" here. Not only is there significant HF loss in the diffuse field due to natural acoustics but we can see that the off-axis HF response of the microphone itself results in significant attenuation (6 - 12 dB) for frequencies above 8kHz at 90-degrees and even greater attenuation as we move towards 180-degrees.

Since normally the diffuse field is off-axis to the mic, we could say that the mic actually exacerbates the problem already set in motion by the acoustics of the room. Thus my response that this HF loss was due to both reasons 2 AND 3.

Somewhat off-topic, but worth mentioning: to my knowledge, this off-axis HF loss is due to the fact that the size of the capsule and body are large enough to be interfering with the smaller wavelengths of HF sound energy. This is the reasoning behind the "needle-nose" design of measurement mic's as well as the Earthworks omni's. A check of the polar plot for a QTC30 will reveal less anomalies in the HF response than that of the Schoeps or Neumann omni's. I have not used these Earthworks, so I cannot comment on them firsthand, nor am I endorsing them over Schoeps MK2's or Neumann KM130's - I am just using their measurements as an illustration.