Intercomm effect and radio effect

Special Interest Groups Audio Processing
1

Hey folks,

I’ve got two seperate effect examples here: an intercom effect and a radio effect (excuse the background music and other voices). I’ve been trying quite hard to replicate these kind of effects in Audacity, and I’ve come somewhat close, but the results haven’t been great.

What would I need to do to achieve such effects? Thanks so much for helping out. ^^,

2

What you have described as intercom is more like Tannoy, ( “PA” Public Address system) .
Adding reverberation and echo can achieve this Tannoy effect.

voice only type Radio (or telephone) can be simulated by a narrow band pass filter which removes frequencies above 5000Hz and below 200Hz (approximate values)
This can be done using Audacity’s equalisation filter.

BTW
The villain’ on your radio sample has had his voice pitch shifted downwards:.
Audacity can do that too: “change pitch without changing tempo“.

The villain’s voice is also slightly distorted by clipping: this can be achieved using Audacity’s “amplifier” at a setting which just causes clipping, then normalising the waveform.

3

Thanks for the reply, Trebor, and excuse my lack for a better word. Followed your advice for the radio effect, and it worked wonderfully (by the way, that villainous voice hasn’t been modified by pitch - it’s just the voice actor’s incredible vocal ability).

As for achieving the PA effect, I tried using reverb but it doesn’t get anywhere close (even with the settings suggested on the wiki page). I’ve tried applying a telephony effect and then echoing it, which is pretty close, but I’m sure I’m missing something.

4

<<<but I’m sure I’m missing something.>>>

Echoes are not A Thing. Echoes, with the exception of a large canyon in Colorado, are a collection of different sound bounces from different walls, floor and ceiling.

This makes them impossible to take out and really difficult to convincingly make. We’ve been known to play sound on a high quality sound system and recapture it in an actual bathroom to get true-to life echo characteristic. And no, with the exception of a couple of expensive software packages, it doesn’t sound anything like the normal echo tools.

Koz

5

To simulate a PA plus intercom my suggestion is:-

  1. Make a copy of your mono track to run alongside the original, using “add new audio track”.
  2. Retard the copy by 150ms with respect to the original, (e.g. “generate” 150ms of silence at its start).
  3. Apply a low pass filter to the retarded copy to reduce its high frequency content.
  4. Apply a narrow band pass filter to the original track, (200Hz - 5000Hz).
  5. Reduce the amplitude of the retarded track by ~12bdB
  6. Optional : add delay / reverb /echo to the retarded track only.

This double track will emulate the sound from the close up speaker (intercom) and the retarded track will sound like a distant public address loudspeaker (slightly delayed , deeper, quieter).


I’ve had a go applying the above to my voice, you can hear the before and after mp3 here.
The 150ms delay is longer than on the sample MrChewy linked to: I am abandoning a bigger ship :smiley: .

6

Well, I followed your advice and the result was excellent. I’m sure with a bit of messing around I could get something even better.

Thank you very much: may all your interstellar voyages be safe :smiley: , lol.

Erm, I think you misinterpreted my statement (and my topic). I’m very well aware as to what an echo is, and I completely understand that programs like Audacity can only apply a rough emulation at best, but all I wanted to do was to emulate the effects used within these two audio clips. I know for a fact that the effects in these clips are all emulated; it’s obvious just listening to them.

Of course, if I was doing anything remotely professional, then I’d most likely invest in a sound system and a decent microphone, but since I’m just messing around for now, Audacity is more than sufficient.