I was wondering what is the best way to isolate specific sounds out of a field recording.

For example, one has a recording of a city centre and wants to isolate the siren of an ambulance passing by for further processing. What would you suggest be the best way or best technique of isolating sound events?

thank you


3 Answers 3


Really depends on the sound and what you are about to with it afterwards. :)

Isolating sounds can be very difficult, snce you can't simply erase the noise around it like in photoshop.

Try EQ and volume automation combined with some multiband expanding. It won't totally isolate your sounds, but as I already said: "isolating sounds....." :)

P.S.:For some special cases (like the sound of a camera flash recharging) Spear is working perfectly.


It is pretty difficult to isolate sounds in a crowded soundscape once they have been recorded without making them sound unnatural. The best solution really is to get the sounds isolated when you are recording them. Using shotgun mics,getting close etc where possible. Otherwise, record your basic sound track and then add in sound effects later, blending them into the background. For example, record a street scene an dthen mix in an ambulance afterwards.


iZotope RX is absolutely wonderful for this sort of thing. The denoise section of it works well on its own, and you can do spectral edits (like in SPEAR), but with much better detail, accuracy, and results. I think there's a trial available on the website.

EQ is also your friend here, but it's sometimes difficult to isolate stuff without losing necessary frequencies. If you're dealing with a siren, you can probably roll off a lot of the low frequencies and not lose anything you need (just a guess, albeit).

I've had great results with it in my often less-than-ideal recording environments.

That said, it really depends on how pure you need the sound to be. Any sound isolation is going to lose something in the edit, especially if it's in a city. It also depends on how much the siren stands out from the background, how loud it is, and what's going on in the background. I wouldn't expect perfect results with city isolation in general, though.

This thread is also going on at the moment: Sound off on Noise Reduction!. It might be of some help.

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