apply audio filter when recording? possible ?

hi all

so for a small experimentation i need to record indoor and outdoor ambient sound via my linux laptop with basic usb mic ,
i would like to ask if in audacity we could apply filter when recording ? like as band ,low , high pass filter and get/record the output result

are there any solutions ?

if there aren’t any real time solution ,
it could be enough for me if the recorded sample is delayed to get the post filter processing result .
what exactly i am looking for is recording live feed audio and process it just behind as output to merge some certain frequency or pattern etc…
thank you all for your responses

Audacity does not apply effects in real time, so Audacity cannot help you with this.

However, as you are on Linux, it is possible to use Jack Audio ( as your sound system, then route the input signal through any Jack aware effects (such as JAMin [JAMin - About]) and then route the signal into Audacity (or other audio recorder). To route the signals you can use QjackCtl How to set this all up is beyond the scope of this forum (it’s really nothing to do with Audacity), but hopefully these pointers may get you started.

The best way to do it would be with hardware: Use a normal (non-USB) microphone, plugged into a mixing desk, and use the Eq on the mixing desk.

Audacity famously doesn’t apply filters, effects or corrections in real time. About the only thing it does in real time is the Timer function. It’s a post-production editor.


Good night

thanks for the responses , i will check jack audio sound when my internet connection will be retablish !

By the way Steve , i am using the encoder and decoder for silent subliminal that you did with nyquist console saw from an old post here in the forum .
just a little question have you an idea if it is possible to do your encoder and decoder with numpy and scipy ?

i 've found a small solution with sox package for recording and apply a filter at the same time,
i run some test with my ubuntu which is equiped with realtek hd
alc3227 audio card and a hand made electret microphone panasonic wm61a and a raspberry pi 2 with cirrus logic audio card with dmic microphone onboard,

this command run on both system :

rec -c 1 -r 192000 capture1.wav sinc 10k silence 1 0.1 1% 1 5.0 1% : newfile : restart

and for generate spectrogram via sox:

sox capture1.wav -n rate 192000 spectrogram -h -o lowultrasound.png

voilà !


I’ve not used NumPy or SciPy, but there are many audio libraries available for Python: