Mic for low vibration/bass-y noise

  • Thread starter Thread starter Dyingfromnoise
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Dyingfromnoise said:
Quick question first, is there any rules to low filter isolation. I might be doing it wrong. As in if I boost the bass in the sample is that bringing out the bass that is recorded or is it making a bass sound(adding to the sound file instead of exaggerating the below end)

Let me get one more with and without vibration sample from better spot for a last chance please. The bass/vibration is constant, like a machine or something

What about spectrum analyzing?

If you email the stuff to yourself you just copy the wetransfer link in the email
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Quick question first, is there any rules to low filter isolation. I might be doing it wrong. As in if I boost the bass in the sample is that bringing out the bass that is recorded or is it making a bass sound(adding to the sound file instead of exaggerating the below end)
 
Dyingfromnoise said:
Quick question first, is there any rules to low filter isolation. I might be doing it wrong. As in if I boost the bass in the sample is that bringing out the bass that is recorded or is it making a bass sound(adding to the sound file instead of exaggerating the below end)
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If you are trying to make 'forensic' recordings you don't want to mess with the response in any way, in fact you really need a measurement microphone and a top grade Sound Level Meter but, a thought has occurred?

The spectrum I posted is of classical white noise? It shouldn't be! The mic picks up random, ambient room sounds, they will not be 'white' and even if they were they would be modified by the frequency response of the mic.

Try again but this time include some speech or if you are shy! Some hand claps. Run the recording back and tell us the peak the waffle or clapping is at (better, attach a screen shot of the DAW's meter)

Dave.
 
ecc83 said:
If you are trying to make 'forensic' recordings you don't want to mess with the response in any way, in fact you really need a measurement microphone and a top grade Sound Level Meter but, a thought has occurred?

The spectrum I posted is of classical white noise? It shouldn't be! The mic picks up random, ambient room sounds, they will not be 'white' and even if they were they would be modified by the frequency response of the mic.

Try again but this time include some speech or if you are shy! Some hand claps. Run the recording back and tell us the peak the waffle or clapping is at (better, attach a screen shot of the DAW's meter)

Dave.
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It’s not white noise, it’s the ambient sound of room coupled with the mic turned up loud. That recording was early morning, nothing was up or going outside.

I can do that request later for you for sure.
 
ecc83 said:
If you are trying to make 'forensic' recordings you don't want to mess with the response in any way, in fact you really need a measurement microphone and a top grade Sound Level Meter but, a thought has occurred?


Dave.
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All I need it a decent recording of this noise (with some noise of me in it) to show how loud and disruptive it is on my house
 
Dyingfromnoise said:
It’s not white noise, it’s the ambient sound of room coupled with the mic turned up loud. That recording was early morning, nothing was up or going outside.

I can do that request later for you for sure.
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Well sorry chap but that recording IS white noise. I make some 10 or so hours of video recording of the wildlife in my garden every night. On even the calmest nights there is always a 'blip' a noise from something, a dog bark in the distance, a train hoot or just a creak or click the nature of which we never know!

Any recording of an 'open mic' outside the NPL's dead room will have blips, yours does not seem to so I suspect some hardware issue there?

Look forward to the new recording.

Oil be beck..

Dave.
 
ecc83 said:
Well sorry chap but that recording IS white noise. I make some 10 or so hours of video recording of the wildlife in my garden every night. On even the calmest nights there is always a 'blip' a noise from something, a dog bark in the distance, a train hoot or just a creak or click the nature of which we never know!

Any recording of an 'open mic' outside the NPL's dead room will have blips, yours does not seem to so I suspect some hardware issue there?

Look forward to the new recording.

Oil be beck..

Dave.
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Interesting, basically I have the shure into the Apollo x8 and turned it up to the max. At night here it’s crazy quiet (except for that vibration/hum) I’ll look into setting up the mic better now
 
Attached is a clip of very early morning in my garden. The crash is a hedge hog flipping a plastic bowel.
You can see from the spectrum (pre crash) that although the noise follows a 'white' spectrum is has curves due to the response of the mics. There are also odd noises off that you will always hear on a high gain mic recording. Note also the 50Hz hum? That is due to lack of WD-40 which the mic conns' need once a month or so!

WTGR I suspect your recordings are just electronic noise?

Dave.
 

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ecc83 said:
Attached is a clip of very early morning in my garden. The crash is a hedge hog flipping a plastic bowel.
You can see from the spectrum (pre crash) that although the noise follows a 'white' spectrum is has curves due to the response of the mics. There are also odd noises off that you will always hear on a high gain mic recording. Note also the 50Hz hum? That is due to lack of WD-40 which the mic conns' need once a month or so!

WTGR I suspect your recordings are just electronic noise?

Dave.
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Understand. From a bit of quick research one thing is I have all the gains too far up. Will test a few different levels. As you said there’s a sweet spot when recording to get everything in.
 
Dyingfromnoise said:
Understand. From a bit of quick research one thing is I have all the gains too far up. Will test a few different levels. As you said there’s a sweet spot when recording to get everything in.
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Err? Not quite! I am saying you are not picking up the 'room' at all otherwise there would be a response curve and odd clicks.

The mic gains on that clip are practically wide open (a Behringer X802) have to be to capture hog snuffles but if a pigeon lands too close to a mic even wing flaps push things to 0dBfs. I actually have a recording of a sonic boom of a year or so back. That went well over!

Dave.
 
So I have been recording in all different places, including some “room” noises too but the Shire just won’t pick up the vibration hum well. Only thing which got something was when I put it into a bongo drum to utilize the skin to help capture more sound which is kind of did. Is there some kind of mic membrane i can get? Does it exist?
 
Dyingfromnoise said:
So I have been recording in all different places, including some “room” noises too but the Shire just won’t pick up the vibration hum well. Only thing which got something was when I put it into a bongo drum to utilize the skin to help capture more sound which is kind of did. Is there some kind of mic membrane i can get? Does it exist?
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Just get a gash 'hi fi' speaker and connect the two cores from an XLR cable to it (Ideally screen goes to speaker chassis but probably does not matter much) If THAT does not pickup the LF then I think you need to take more water with it!

Dave.
 
ecc83 said:
Just get a gash 'hi fi' speaker and connect the two cores from an XLR cable to it (Ideally screen goes to speaker chassis but probably does not matter much) If THAT does not pickup the LF then I think you need to take more water with it!

Dave.
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Appreciate the reply, I want to try this but the description went over my head. Can you dumb it down for a noob
 
You're not going to pick up much below about 50Hz with most conventional microphones. If you look at the response curves of the majority of commercial microphones, you see a serious roll off, usually in the 10-20dB/octave range below that point. You can't necessarily go by the claimed "20-20kHz" spec on most microphones, because they NEVER state the deviation from 1kHz, which is the way most electronic equipment is measured, like interfaces and amplifiers. Mics will have deviations of +/-10 or 20dB which is HUGE!

If you need to record sounds in the 10-30Hz range, you need to be looking at an omnidirectional measurement mic, such as the Earthworks M23, or the Audix TM1. The Earthworks has a response down to about 5-9Hz, which is subsonic. If you can't record it with that, then you really don't have a problem.

Do you have any idea what the source of this low frequency sound is? Are you near industrial equipment? Is there construction nearby? Is there a roadway with heavy traffic? These would be some sources of low frequency noise.
 
This is great information, thank you.

I recently figured the noise is coming from my next door neighbour, our houses are detached but both have a semi underground basement separated by about 3/4 meter (soil) I’m not sure what machinery or fan they have but it’s aggressive for sure. As they kind of denyed anything before I would like to get some solid recordings before talking to them again. Also when people are visiting it is never on so it can be tricky without some recording/evidence
 
If I did get the Earthworks and it picked up what I am hearing would it be easily played back from my daw or would some processing also needed to be done?
 
If your microphone can hear it, the DAW should record it.

FWIW, this is the response curve of the M23.
M23-frequency.webp

This is the response curve of the SM58.
f_7e014e2c-0e64-4316-9359-a69f034adcd0-ENG.webp


See the difference?
 
Attached is a rather blurred shot of the back of a small speakers with an XLR 'tail' connected.

If you cannot make up such a cable you can donate a mic lead.
Tomorrow I am going to put that speaker on my living room floor and run some LF tones through my system and record the result.

The point you asked about 'enhancing' the recordings? Don't IMHO or if you do make it abundantly clear that you have only done so for better clarity and have the original, untreated .wav available for scrutiny.

Dave.
 

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Ok, just done it. Attached is the 30Hz tone* repro'ed through my home hi fi (kept level modest but still annoyed wife!)

The analyser plot is interesting? You can easily see the 30Hz picked up by the very small speaker, 4" woofer but the third harmonic at 90Hz dominates. Whether that is my speakers distorting or the wee one acting as a microphone I cannot say, bit O both I would guess.

Still, the principle works and you can use a relatively small speaker to record very low frequencies.

The speaker BTW was plugged into my NI KA6 and the mic gain whacked to max.

Hope this helps.

* I tried to record a 20-100 sweep sine but that did not turn out well.

Dave.
 

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  • 30Hz speaker.webp
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