Topic: New omni mics, or keep what I have? (diffuse vs. free field omnis)

[voltronic]

Thanks to DSatz for his recent post on the Schoeps MK 3 / MK 2 XS, which might possibly save me some money now that I'm thinking through my recording situation more thoroughly.

I had been planning to purchase a pair of Line Audio OM1 omnis after being knocked out by their sound in all of the samples that I've heard.  Now I'm starting to reconsider, thinking that it might make more sense to just keep my Naiant X-Q omnis.  Comparing the specs, the OM1s have a very flat nearfield response, whereas the X-Qs have a bump above 10kHz.  Jon mentioned that this has likely benefited the more distant recordings I've been using them for recently.  I'm concerned that the very flat response of the OM1s will cause them to sound dull at significant distance by comparison.  I rarely get the opportunity to record up close.  The OM1s are also less sensitive the X-Qs, although they have much higher SPL handling and a bit lower self-noise.  I suppose that I could try and compensate for the HF losses at a distance with EQ, but I'd prefer to just use the correct type of microphone in the first place, and suspect that I already am.

Aside from the aforementioned MK 2 XS which are out of my price range, I'm thinking something like the MBHO MBNM 410 would be a better choice for me than the OM1.  That's down the road though - for now I think I'm sticking with what I have, which is working great for me.  Does my line of thinking make sense?

http://www.lineaudio.se/OM1.html
http://naiant.com/x-q-specification/
http://www.nohypeaudio.com/mbhoproducts.htm

[2manyrocks]

The more fundamental issue is whether you would benefit from a hypercard to focus on what you want to record when stuck recording from a distance. 

Now I'm about to say something contradictory. 

I keep returning to my DPA4061s because I can discreetly place them, and they are easy to carry. Take your chances on a pair of ex-theater mics and you could get a pair for $300, but you'd have to get phantom power adapters or use a battery box to power them.  I've taped them to the back of church pews down front, and they were completely off the radar except for those of us on the first couple of rows.  The problem is keeping people's hands off them because they totally forget they are there. 

[voltronic]

The more fundamental issue is whether you would benefit from a hypercard to focus on what you want to record when stuck recording from a distance. 

Now I'm about to say something contradictory. 

I keep returning to my DPA4061s because I can discreetly place them, and they are easy to carry. Take your chances on a pair of ex-theater mics and you could get a pair for $300, but you'd have to get phantom power adapters or use a battery box to power them.  I've taped them to the back of church pews down front, and they were completely off the radar except for those of us on the first couple of rows.  The problem is keeping people's hands off them because they totally forget they are there.

That's interesting, I was just looking at DPAs site and wishing I could afford a 4006 pair.  The 4060s or 4061s look very attractive, and I like that they include the soft and high boost grids which seems to make them more versatile in terms of recording distance.  I know Gutbucket has had great results with the little DPAs.

[acidjack]

If keep what you have and not make an incremental upgrade that you ultimately won't be that happy with.

[DSatz]

Just a general comment about microphones and recording distance: Yes, a diffuse-field omni (or something in that direction) helps you get a desirable frequency response for more distant recording, as compared with a free-field type. But getting the frequency response you want is just one issue, while the degree of reverberation vs. direct sound in the recording is another. Just because a certain type of omni gets you good frequency response with distant placement, doesn't mean that you'll like the result if it's all swimmy and swampy.

No one is saying that an omni mike is necessarily the best choice or even a halfway good choice for distant recording; it's just that IF it proves to be a good choice (given the sound sources and the nature of the space in a given situation), THEN a diffuse-field omni is the type you'd most likely want to use there (and I suggest add-on spheres as well--they really do help to overcome distance). But in many years of recording, I have experienced that situation only rather rarely. Now, normally I'm the hired engineer at the performance, so within the constraints of sight lines and lighting, I can usually place my mikes where I feel they need to be. If I'm forced to make a recording without that privilege, and instead have to place a pair of mikes farther away than I consider optimal, with no spot mikes of any kind, I would use supercardioids as 2manyrocks suggests.

However, any microphones used at a distance need to have off-axis response that is highly "listenable" (e.g. not peaky in the treble), since so much of the arriving sound energy will be arriving from off-axis. Among supercardioids that quality is available only from small, single-diaphragm condensers--and even among those, you still need to choose carefully, since most manufacturers of highly directional microphones (including both supercardioids and shotguns) are aiming for the speech pickup market primarily (film, video, PA sound, etc.) where intelligibility is the goal at the expense of naturalness. In a diffuse sound field many highly directional microphones--not just low-priced ones--tend to have rather weak bass response and a peaked-up upper midrange, followed by a steep drop at higher frequencies. For music recording you want microphones that are smooth and flat in their overall response, i.e. their off-axis response runs essentially parallel to their on-axis response, without excessive peaks or dips.

This is where polar diagrams will tell you crucial stuff that a frequency response curve alone can't. It would be even better if manufacturers would publish diffuse field response curves for their microphones--but unfortunately there is no standard method for producing a test signal for that, so the diffuse-field response has to be inferred from the 0-degree curve and the polar diagrams.

--best regards

[voltronic]

Sometimes I think about an X-Q reissue with the current X circuit and a newer, quieter capsule.  But then I think I have to differentiate it from the X-R, which is quieter than any 6mm capsule will be, and can have the EQ disc attached.  That's my favorite configuration in my current lineup.

I use the same capsule in the X-O, but with a filter to tone down the highs a bit, because again that needs to be different from the X-R.  The intention for the X-O is to be something that can be abused, whereas the X-R is more delicate, so I tailor their EQ curves with their intended use in mind.

Consider that's essentially the difference between the two types of omnis, an EQ you can apply yourself.  I put filters in the mics because many customers seem to think there is something sacred about the FR of a microphone.  There really isn't unless you are talking about the consistency of on- vs. off-axis response, which isn't an issue for a pressure omni.

That's a very candid explanation - thanks.  So does your equalization disc for the X-R function at all like a Neumann sphere, or the DPA boost grids?  I notice from you FR graphs that the off-axis response does not change with the disc attached.

[voltronic]

Just a general comment about microphones and recording distance: Yes, a diffuse-field omni (or something in that direction) helps you get a desirable frequency response for more distant recording, as compared with a free-field type. But getting the frequency response you want is just one issue, while the degree of reverberation vs. direct sound in the recording is another. Just because a certain type of omni gets you good frequency response with distant placement, doesn't mean that you'll like the result if it's all swimmy and swampy.

No one is saying that an omni mike is necessarily the best choice or even a halfway good choice for distant recording; it's just that IF it proves to be a good choice (given the sound sources and the nature of the space in a given situation), THEN a diffuse-field omni is the type you'd most likely want to use there (and I suggest add-on spheres as well--they really do help to overcome distance). But in many years of recording, I have experienced that situation only rather rarely. Now, normally I'm the hired engineer at the performance, so within the constraints of sight lines and lighting, I can usually place my mikes where I feel they need to be. If I'm forced to make a recording without that privilege, and instead have to place a pair of mikes farther away than I consider optimal, with no spot mikes of any kind, I would use supercardioids as 2manyrocks suggests.

However, any microphones used at a distance need to have off-axis response that is highly "listenable" (e.g. not peaky in the treble), since so much of the arriving sound energy will be arriving from off-axis. Among supercardioids that quality is available only from small, single-diaphragm condensers--and even among those, you still need to choose carefully, since most manufacturers of highly directional microphones (including both supercardioids and shotguns) are aiming for the speech pickup market primarily (film, video, PA sound, etc.) where intelligibility is the goal at the expense of naturalness. In a diffuse sound field many highly directional microphones--not just low-priced ones--tend to have rather weak bass response and a peaked-up upper midrange, followed by a steep drop at higher frequencies. For music recording you want microphones that are smooth and flat in their overall response, i.e. their off-axis response runs essentially parallel to their on-axis response, without excessive peaks or dips.

This is where polar diagrams will tell you crucial stuff that a frequency response curve alone can't. It would be even better if manufacturers would publish diffuse field response curves for their microphones--but unfortunately there is no standard method for producing a test signal for that, so the diffuse-field response has to be inferred from the 0-degree curve and the polar diagrams.

--best regards

I've never had the opportunity to use super- or hypercardioids, but I understand the principle behind what you're saying.  I would suspect that I would still want to have a set of omnis in the mix as the loss of bass at distance will be even greater.  I don't think they would stand on their own for somewhat distant acoustic recording which is the situation I'm in most often.

Regarding your point about off-axis response - I think that's why I enjoy the CM3 mics so much, as their on/off-axis response is quite consistent up to about 16kHz (according to the plots) and I find them quite forgiving of placement especially in the vertical plane.