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What does 90° and 180° on a frequency response chart actually mean? Virtual Instrument Plugins
Old 31st August 2011
  #1
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What does 90° and 180° on a frequency response chart actually mean?

What does 90° and 180° on a frequency response chart actually mean? Never really thought about it before.

i.e. when the response is shown on a chart for 90°, as opposed to on-axis, what would that actually look like if it was, say, a standard front-address mic recording a voice? how would that mic be positioned?

Would it be at 90° facing away from (not towards) the singer's mouth? (Or would that be 180°?)

Or would it mean that the mic was positioned vertically (i.e. so the singer's breath was hitting the side of the capsule)?
Old 31st August 2011
  #2
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matt thomas's Avatar
I'm not 100% sure I understand the question, but I think the second answer, the side of the capsule, is what you mean

matt
Old 31st August 2011
  #3
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Sorry, it's a simple, dumb question, I'm just not putting it that well.
Let's pretend for the sake of this thread that I am so stupid that I don't know what 90 degrees/180 degrees etc looks like. Humour me, it's the Newbie threads...

When a frequency response chart for a microphone gives a response for 90 degrees and also 180, it presumably means "at 90 degrees to the source/at 180 degrees to the source", right?

I have a pencil mic and I want to take advantage of the increased bass response that the chart suggests I'd get at 90 degrees. So that would mean having the mic totally vertical, sticking straight up in the air?

And, likewise, 180 degrees would mean effectively talking into the back of the mic, right? Having it back to front?



(that's the closest smilie I can find to the lobotomised neanderthal that I must sound like...)
Old 31st August 2011
  #4
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matt thomas's Avatar
Quote:
Originally Posted by binarymilton View Post
Sorry, it's a simple, dumb question, I'm just not putting it that well.
Let's pretend for the sake of this thread that I am so stupid that I don't know what 90 degrees/180 degrees etc looks like. Humour me, it's the Newbie threads...

When a frequency response chart for a microphone gives a response for 90 degrees and also 180, it presumably means "at 90 degrees to the source/at 180 degrees to the source", right?

I have a pencil mic and I want to take advantage of the increased bass response that the chart suggests I'd get at 90 degrees. So that would mean having the mic totally vertical, sticking straight up in the air?

And, likewise, 180 degrees would mean effectively talking into the back of the mic, right? Having it back to front?



(that's the closest smilie I can find to the lobotomised neanderthal that I must sound like...)
Yes, but there are three directions, which means that there are a number of ways the mic could be pointing in order to be 90 degrees off the source. It could be pointing straight up, straight down, straight sideways, or any direction on a circle through these points.

180 degrees on the other hand is always straight away from the source.

You should consider reflections off the wall/ceiling/floor too

BTW. This wouldn't normally be used as a way of getting more bass response, but there is no reason it shouldn't be, if you like the sound of it.

matt
Old 31st August 2011
  #5
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Quote:
Originally Posted by matt thomas View Post
Yes, but there are three directions, which means that there are a number of ways the mic could be pointing in order to be 90 degrees off the source. It could be pointing straight up, straight down, straight sideways, or any direction on a circle through these points.
right, of course, hadn't really thought about that. I often - in fact I usually - position vocal mics upside-down above the singer, pointing down at their mouth: partly because it's how they always have it in old studio photos, partly because it keeps the mic away from their sibilance'n'pop-inducing mouth, and partly because it tends to sound good.

I imagine some of that 'sounding good' is that it's not totally on-axis. It might be pointing down more or less towards the mouth (just in front of, in fact), but it's not dead-on.

Thanks for the reply. Sure, the first thing I'd do if I wanted a warmer sound is reach for a warmer-sounding mic, but I started wondering about off-axis business in the first place because I'm doing a lot of fiddling about with room mics (have moved to a new office building with some cool rooms to location-record in after hours...)
Old 31st August 2011
  #6
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claend's Avatar
 

EDIT - Ok, just read the thread, sorry!
Old 31st August 2011
  #7
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frans's Avatar
The solution to the arcane black art of mic positioning is actually pretty unspectacular. Get isolation headphones, route the signal from the mic so you hear what the mic hears. No you can try every position, angle, distance and whatever you want. Instantly you hear what difference it makes and you can make an educated decision. Forget about specs and paperwork, they won't save you if you can't apply the knowhow.
Old 3rd September 2011
  #8
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Quote:
Originally Posted by binarymilton View Post
I have a pencil mic and I want to take advantage of the increased bass response that the chart suggests I'd get at 90 degrees. So that would mean having the mic totally vertical, sticking straight up in the air?
Keep in mind you're not getting better bass response, you're getting worse response across the other frequencies.

This isn't to say that using mics off-axis is always a bad idea, but it's not the best way to accentuated bass (a mic positioned close to use the proximity effect, with a good flat bass response and a dip in the low-mids is probably a better way).
Old 3rd September 2011
  #9
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read the spec sheet
not all mikes are oriented the same way
some are 0 when pointing the end to the source
some are 0 when pointing labelled side toward the source with point up
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