How does diaphragm size/polar pattern relate to mic applications?

  • Thread starter Thread starter Chris F
  • Start date Start date
Status
Not open for further replies.
Metaxy said:
Here's a question: If omni mics work on an entirely different principle than cardioid, how come the Oktava MK012 can be switched to omni just by attaching a new head?
Click to expand...

Another, more simplistic take on it: The type of mic is really all in the head. That's where the 'capsule' is and the capsule defines it. The rest of it is simply its preamp (not to be confused with a 'mic pre'). So some have a whole series of heads available, cardioid, wide cardioid, omni, hypercardioid, etc. Look particularly at the high-end lines like the traditional AKG's, Schoeps, Neumanns, DPA...
 
Ah, I get it, so the whole capsule enclosure is all in the head anyway.

K, works for me.

My next question, not quite worthy of a thread of its own, is: is it really possible to damage a mic just by being too loud? Even if it's unplugged?
 
Metaxy said:
Ah, I get it, so the whole capsule enclosure is all in the head anyway.

K, works for me.

My next question, not quite worthy of a thread of its own, is: is it really possible to damage a mic just by being too loud? Even if it's unplugged?
Click to expand...
Yes, in the case of ribbon mics, which can be damaged by air blasts, even if unplugged.
 
Mr. Gerst

I too, would like to forward my appreciation. This post has been and continues to be quite a study.
I hope that one day I can pass along some of my knowledge in a worthy fashion much the way you have.
You are an insperation.

Thank you
Tom
 
this is an amazing resorce. its gonna take weeks for it all to soak in. thank you mr. gerst. you have my deepest respect.
 
Trappe said:
this is an amazing resorce. its gonna take weeks for it all to soak in. thank you mr. gerst. you have my deepest respect.
Click to expand...
"Mr.Gerst" was my grandfather; I'm just Harvey. I'm sorry I wasn't around to answer some of your questions about me.
 
Why is it that small-diaphragm condensers are used more often in pairs than large-diaphragm ones?
 
Metaxy said:
Why is it that small-diaphragm condensers are used more often in pairs than large-diaphragm ones?
Click to expand...
Since small diaphragm mics are often more accurate than large diaphragm mics, they're used for stereo recordings where imaging might be critical. The coloration of large diaphragm mics makes them generally more suitable for vocals or situations where stereo recording is less critical and where flattering coloration is more important.

This is of course a gross oversimplification of the situation and many large diaphragm mics can be used very successfully in pairs for stereo recording.
 
Last edited:
Stereo accoustic guitar

Hi

I do not yet own a pair of mics i could use to do a stereo recording of an accoustic guitar.
I am getting a Rode NTK. Could I record the guitar twice with the NTK and pan them left and right?
Or is there a better way?

Thanks
Tom
 
You might get some interesting flanging or phasing effects if you can play an almost perfect duplication, like doubling a vocal track for a fuller effect. But if it's not almost perfect, it will just sound like two guitars playing. But it won't be stereo.

You could also just record one track, copy it to a second track with several milliseconds of delay, then pan left and right for a fuller sound.
 
crazydoc

Thanks for the reply.
How well does the NTK work on accoustic guitars?

Tom
 
crazydoc said:
You might get some interesting flanging or phasing effects if you can play an almost perfect duplication, like doubling a vocal track for a fuller effect. But if it's not almost perfect, it will just sound like two guitars playing. But it won't be stereo.

You could also just record one track, copy it to a second track with several milliseconds of delay, then pan left and right for a fuller sound.
Click to expand...
This is a great trick for home recordists, but a very bad idea for any studios that might be recording stuff that will get a lot of airplay. If the signal is ever combined to mono (which FM does on weak signals, AM radio, or a LOT of TVs still out there), there's a good chance the tracks will cancel almost completely.

Same thing goes for using that trick to fatten vocals. It can work well, but always check the mix in mono for problems.
 
Incidentally, what is it that makes larger diaphragm makes smoother but less accurate? Is it that the large diaphragm responds to vibration less quickly and so takes more time to respond to aural details and hence blurs over the subtleties?
 
wizcow said:
crazydoc

Thanks for the reply.
How well does the NTK work on accoustic guitars?

Tom
Click to expand...

I like it a lot on acoustic guitars. The upper mids need to be scooped though. I've had great success putting in close at the 12th fret. I've also noticed that it sounds better on guitars that are sort of neutral to dark sounding...I don't mean really dark sounding, I just mean not bright sounding. It can make acoustics sound nice and punchy.
 
Understanding Ribbons... or not

I have been digesting this thread for the past few weeks (incredible series) and am finally starting to get a visualization of why my current recording settup for the harp works (which took much experimentation with little understanding). As I have been going along I have been pulling out sections that I found particularly pertinent. I have been considering getting a ribbon mic, but want to see if I have a reasonable understanding of where they would be applicable. So I am going to start with putting in a number of Harveys notes here, & then extrapolating as to how I want to use it. Responses as to whether my extrapolations are totally bogus would be greatly appreciated.

"So why use a ribbon mic (that typically has a low SPL rating)? Ahhh, the sound is wonderful. Many ribbon mics use ribbons that are only 7/10ths of a micron thick (a typical human hair is about 20 microns thick by comparison).
The ribbon in a ribbon mic has essentially minimal mass and responds beautifully to a lot of signals, such as voice, strings, horns, etc.. The resonance can be set very low (20Hz on an RCA 44BX), and that single piece of corregated aluminum ribbon has almost no other resonances, so it's very flat and smooth throughout its entire response range. "

--Here we get the idea of the lower than normal resonance for a ribbon (at low frequency which is handy), now Harvey again:

I was primarily thinking of Figure 8 ribbon mics when I wrote that but some of it holds true for all figure 8 patterns. Figure 8 patterns have the most proximity effect possible, which can really enhance some vocals. Ribbons have a smooth, silky sound to them which compliments a great number of voices. Figure 8 patterns have the smoothest off-axis response of all gradient polar patterns AND:
they eliminate a large part of the resonant, transient, and axial difficulties of other microphone designs.
--Ok so we can use figure 8 for off-axis response, and tuning what is picked up. Emphasis on the elimination of resonant difficulties.

Now lets flip over to a problem that was mentioned for playing acoustic guitar:
As you mentioned, Every acoustic guitar has certain resonant frequencies which seem to dominate the recorded sound and can even mask the beauty of the instrument or ruin the desired tone as well as drowning out what is being played.
To this Harvey responded that: distance is your friend.

Now to my problem, for which you should assume a well dampened room. You can think of a harp as a guitar with very large & very resonant body. The difference is the how the strings are attached to the resonant body, as they come off perpendicular to the acoustic body. It would seem that with a ribbon mic you could do close mic-ing, and select how much of the tone you are picking up from the strings, and how much from the resonant body by the angle which is selected. With the ribbon not having all the additional resonant responses it seems that it would be ideal for this overly resonant instrument. Am I all wet?

One other question on Ribbons, I love the detail that small condenser mic's give me, will I still have that with a ribbon? Do they have a good transient reponse? I have seen reviews where a ribbon is considered a first pick for stringed instruments, but I had the impression that this was for instument played with a bow, not picked. This would seem to be a case where 'detail' is not as important (smooth transients).
 
garf, you bring up some really excellent points, and harp is one of the more difficult instruments to capture, partly because of its design. In a large room, it projects very well, but in a smaller studio environment, most recordists run into a few problems. Solo concert harps in small rooms aren't very loud. Miking a harp in close will pick up pedal noises, which are annoying as hell. The sound from a harp has strange projection angles.

So, given the above problems, how the hell do you get a decent recording of a concert harp recording in a less than concert hall sized environment, and what mics are likely to work best?

Ribbons do work wonderfully for recording harp, as long as they are placed outside the "near field" to avoid proximity buildup, but then you hafta deal with the extra amplification needed, which translates to a lot of bucks being shelled out for really quiet preamps.

Condensers work better for introducing less noise and generating decent recording levels, but most condenser mics have high frequency peaks that cause some really nasty edge to the high end of a harp. The smoother condenser mics (like a Schoeps CMC-6 body, with the MK41 hypercardioid capsule) have the reach and smoothness needed for great harp recordings, but a pair of Schoeps are around $2,600; not exactly home studio fodder.

I tried using a Coles 4038 ribbon to record some concert harps, but the room was way too small, and I had to work in way too close. After going thru every mic I had on hand at the time, I settled on a pair of Shure SM-81's.

Looking back (and with my increased mic arsenal), I'd probably try a pair of AEA R84 ribbons, the MXL 603's, the Oktava MK012's with the hypercardioid capsules, and possibly the T.H.E. small diaphragm mics with their hypercardioid capsules. My gut feeling is that if I were doing a national release of a harp album, I'd rent/beg/ borrow/steal a pair of Schoeps mics.

My biggest mistake was recording in too small a space to start with. Next time around, I'd be more concerned with the harp's environment, and less concerned about the mic selection. I'd ask around and find a church that might let me use their room. I'd pull the mics back until I started to run into noise buildup from overamplification.

Recording a concert harp decently is a wonderful challenge, and the reward is so satisfying. I hope some of this will be of some small help. Good luck.
 
Fascinating, its really interesting to get your take on this, and to hear what your recommendations are for mics. So far the harp recording that is the best (production wise) that I have heard was done by Vintage Studios, with David Brown as the engineer. There they used a Neumann KN64 tube mic, and a Neuman M49 LD mic (2 of each). This was a recording of Kim Robertson done in 1987. It sounds like they had a magic dial for choosing the amount of resonance from the harp sound board versus the string tone. Unbelievably clear. I wonder if they had a way to set the microphones where they could get some cancellation of the reverb/resonance.

For my easy to record harp (not too large a soundboard) I find the only way to get the string tone detail is to mic close in. But that can give some of that 'nasty high edges' you are describing. I am fortunate that the room is not small (27x15) so it projects well. For the loud 'bass' harp(I call it bass because of the extreme amount of resonance & how loud it is), well, that is still a challenge to be met. My wife has about 24 original harp pieces that I would like to get a good recording of. Not classical, not bluegrass, not celtic, not new-age, I am not quite sure what genre it would fall in (mellow bluegrass if i had to guess). Some of these pieces definitely sound best on the 'bass' harp, so this is an ongoing challenge.

Have you ever heard of techniques for cancelling resonance to emphasize the string picking? Also, do you think the Grace design 101 is up to the challenge of a ribbon, or do I need a ribbon like a Royer R122 with a built in pre-preamp. I was eyeing an Oktava ML52 ribbon simply because they do not cost a fortune, but not sure if the mic preamp is up to it.

But then again, hearing your comments on how important the room is, I think I will invest in some damping, and more time on mic placement. Some of the techniques I have read here for violin (such as mic-ing underneath) have some possiblities.
 
garf said:
Fascinating, its really interesting to get your take on this, and to hear what your recommendations are for mics. So far the harp recording that is the best (production wise) that I have heard was done by Vintage Studios, with David Brown as the engineer. There they used a Neumann KN64 tube mic, and a Neuman M49 LD mic (2 of each). This was a recording of Kim Robertson done in 1987. It sounds like they had a magic dial for choosing the amount of resonance from the harp sound board versus the string tone. Unbelievably clear. I wonder if they had a way to set the microphones where they could get some cancellation of the reverb/resonance.

For my easy to record harp (not too large a soundboard) I find the only way to get the string tone detail is to mic close in. But that can give some of that 'nasty high edges' you are describing. I am fortunate that the room is not small (27x15) so it projects well. For the loud 'bass' harp(I call it bass because of the extreme amount of resonance & how loud it is), well, that is still a challenge to be met. My wife has about 24 original harp pieces that I would like to get a good recording of. Not classical, not bluegrass, not celtic, not new-age, I am not quite sure what genre it would fall in (mellow bluegrass if i had to guess). Some of these pieces definitely sound best on the 'bass' harp, so this is an ongoing challenge.

Have you ever heard of techniques for cancelling resonance to emphasize the string picking? Also, do you think the Grace design 101 is up to the challenge of a ribbon, or do I need a ribbon like a Royer R122 with a built in pre-preamp. I was eyeing an Oktava ML52 ribbon simply because they do not cost a fortune, but not sure if the mic preamp is up to it.

But then again, hearing your comments on how important the room is, I think I will invest in some damping, and more time on mic placement. Some of the techniques I have read here for violin (such as mic-ing underneath) have some possiblities.
Click to expand...
The Grace should be fine.

You have the luxury of working at a slower pace than a commercial studio, so experimenting is free. Try everything you can think of, no matter how crazy it seems. You have to record a unique instrument, with a unique player, in a unique environment, with a limited amount of resources.

Before throwing money at the situation, try throwing unique ideas at it.
 
Harvey Gerst said:
Before throwing money at the situation, try throwing unique ideas at it.
Click to expand...

I'm gonna frame that and hang it on the wall, right next to "Difference of opinion is the essence of collaboration".

Cheers,
 
Status
Not open for further replies.
Back
Top