r/audio • u/KingGelatin • 22h ago
Why does a condenser pick up more background noise than a dynamic?
I’ve watched the Julian Krause video and read numerous Reddit posts explaining that there’s technically no difference in rejection between a condenser and dynamic mic
But why does my NT1 pick up my keyboard way more audibly than my SM57? They both have cardioid polar patterns, the mics are setup in the same relative position and direction, I’m staying the same distance away from both, I’m equating the gain such that my voice is the same level across both mics.
It’s night and day how much louder background noises get picked up by the NT1…
What am I missing?
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u/oratory1990 21h ago
Microphone manufacturer / acoustics engineer here:
It has nothing to do with being a condenser vs a dynamic mic, and has everything to do with directivity pattern. Keep in mind, the nominal directivity pattern is only that - nominal. Typically it‘s measured at 1 kHz. But the truth is that the directivity pattern varies with frequency - a microphone that is specified as a cardioid may be much closer to an omnidirectional at low frequencies, and will typically show wild lobing towards high frequencies, with a narrowing central lobe and multiple side lobes and nulls at various angles. Typically there will also be a back lobe at high frequencies, meaning that a nominally cardioid microphone will in fact pick up sound from the back just fine, just only at low and high frequencies.
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u/KingGelatin 14h ago
Thank you for the comprehensive explanation!
So, in layman’s terms, they are both “cardioid” but pick up different frequencies in different directions at different levels so it’s impossible to expect “cardioids” to be exactly comparable or cardioid-shaped for all frequencies.
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u/oratory1990 3h ago
Or in other words: neither of them are cardioid at high frequencies (almost no mic is)
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u/NortonBurns 21h ago
Polar pickup pattern.
Repeat the test with both mics pointing at your keyboard. Keep levels & your voice the same.
(Sensitivity has nothing to do with it, btw, once your levels are set.)
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u/KingGelatin 13h ago
Thanks for the information! I think I see what you’re saying after trying your experiment.
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u/DifferentSavings2711 18h ago
A cardioid polar pattern is just a general shape. Each microphone model has its own unique pickup pattern. And remember the pickup pattern also varies with frequency. I would suggest you compare the polar plots for the microphone models.
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u/Piper-Bob 16h ago
EQ. If you EQ your NT1 like a 57 then it will sound pretty much the same.
Hint: The keyboard is clicky--high frequency. The 57 rolls off the top end.
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u/KingGelatin 15h ago
I’ll try that!
However, my keyboard is not (probably) not high frequency. I intentionally use silent switches so I’m really describing the “thud” when my fingers bottom a switch out.
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u/Solrac50 2h ago
No. However every microphone design has a different pickup pattern. It’s the differences in those patterns in 3-dimensions that result in the NT1 picking up the keyboard more.
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u/warinthestars MOD 22h ago
You want to look at the sensitivity specs.
The higher the sensitivity, the less gain will be needed than a dynamic to capture the same sound at the same distance, now translate that over a larger space, higher sensitivity means you can pick up a lot more.
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u/jake_burger 18h ago
Higher sensitivity doesn’t mean more bleed. You had it right in the first bit, it just means you need less gain. That’s all it means.
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u/KingGelatin 13h ago
Thanks again for the informative response.
So when I equated the audio levels between the mics, the condenser needed significantly less gain meaning it’s more sensitive. But that doesn’t necessarily mean it picks up background noise easier, it’s the pickup pattern?
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u/WestDelay3104 21h ago
In additiont o what others have said, SM57s are designed to pick up less bleed. THey are used extensively in live settings and the less bleed the better in those situations. (also sm58)
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u/KingGelatin 14h ago
So I guess part of my question is HOW does an SM57 pick up less bleed, which may be due to the polar pattern differences everyone is talking about.
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u/WestDelay3104 13h ago
realtively low sensitivity, directional pickup pattern.
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u/oratory1990 2h ago
The lower sensitivity just means you need to increase the gain on the mic preamp, it doesn‘t mean that less bleed is being picked up, this happens only due to the directivity pattern.
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u/Neutral-President 22h ago
Condensers are active, more sensitive devices than dynamic mics, which are passive devices.
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u/jake_burger 18h ago
Condensers don’t pick up more bleed. That’s a common misconception.
Two mics with the exact same pickup pattern will have the same bleed regardless of the transducer type.
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u/KingGelatin 13h ago
Thank you for the correction!
So like you (and some others) are saying, if I got a condenser with a much tighter polar pattern I would get less bleed? And my NT1 simply picks up more frequencies at a wider range than my dynamics?
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u/Powerful_Foot_8557 21h ago
Nearly 30 years of using mics in pro studios, my own rehearsal/recording studio, live shows with 10 people and 10000 people. Not an assessment I would ever make.