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    1345 sounds
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    Proximity effect


    Hello

    Perhaps a more experienced user can answer my question?

    I do not have a lot of experience with mics (proper expensive mics, that is), but I know from reading about it and from experiencing it with my cheap mics that microphones suffer from what is called "proximity effect".
    I seem to have read somewhere that for many mics, the close the mic is to the sound source the more it emphasizes bass frequencies. But I believe this is only half of the story...

    Again, my experience is with cheap mics, but I often experienced the "long distance" effect rather than the proximity effect.
    We have all eard it: a mic picks up the voice of someone close up perfectly fine, but someone else a few meters away, or perhaps in the next room sounds reverbering and far away. Almost like it wouls sound to your ears as if he/she was talking from accross the road rather than from accross the room.
    Why is this?
    Are mics better at picking up ambience reflections (i.e., reverb) than our ears?

    hmmmm..... erm..... I forgot...
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    One definite factor is that omni directional mics will over-emphasise room ambience compared to our ears, so cardiods or unis pointed toward (or adjacent to) the subject will give the balance you are looking for. Most cheap mics are omnis so this probably accounts for your observation. The other thing that seriously improves intelligibility is a fairly decent stereo arrangement rather than mono, because our brains use the delay/phase information to pick out and localise individual sound sources from a background babble.

    You might be surprised at the quality of recording you can get from a very cheap mic if you experiment with a shell of acoustic "baffling" behind and around it (them, stereo) to absorb room reflections. A cheap arrangement can be constructed using , say, a tin can lined with carpet scraps and/or a layer of stuffing (feathers/polyester fibre) on the surface. The rule is very heavy layer to absorb low frequencies, a medium density layer to absorb mid frequencies and stop any reflections from the heavy layer topped by a light fluffy layer to break up direct reflections and absorb high frequencies.

    It's all suck it and see - a very cheap area for experimenting with scraps at hand.

    Regards,
    Wibby

    Heaven in the sky is to die for, Heaven on earth is to live for.
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    1345 sounds
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    Definetely worth a few experiments !
    Thanks

    hmmmm..... erm..... I forgot...
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    Well, the proximity effect does not occur with omni mics, so if you observe the effect while being close to the mic, you can be sure it's not an omni smile
    However, it could well be a cardio, and that's still pretty wide, so you'll likely get reverberations from farther away recordings.

    Weird thing however I once noticed, I was recording a ringing cell phone in a special sound booth, but we couldn't get it to sound like it was 'far away'. We had several meters inbetween the phone and the mic, but it sounded like it was much closer. We could only get it to work when I held the phone behind my back, I actually had to stop the direct sound. tongue

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    Hey, first post here. Are you are right that increased bass response is only part of the picture. You actually get a slight increase on the high end as well, even though it is much less than bass increase. You also get a lot less of the room sound, and tone alterations that vary depending on what source you are recording.

    When you are far away you will pick up a great deal of room reflection. We actually hear a great deal of room reflection in our day to day lives, the only difference is that we can use our brains to focus on direct sounds and not consider room sounds. Anything except a hypercardioid pick up will let in a great deal of ambiance. Hypercardioids at a distance, usually above and aimed down at the source generally do a good job of emulating how we choose to hear sound in our daily lives.

    As for a cellphone in an iso room - you have emphasis on the 1khz range and not much else. Most treated rooms get rid of this frequency range. The amount of reflection coming off of a 1khz tone in an absorption based room is going to be easily -30 to -50 db spl less than the source sound.

    www.bobbyeli.com

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