Remove echo from recording

I have a recording of a person giving a talk before a live ausience, in a large room at a New York hotel. I made this recording many years ago, on a mini cassette recorder.

I just transferred the recording to my PC, by using Audacity (recording from the Line In input). There is a nasty hiss throughout the recording, probably due to the tape hiss. I managed to remove the hiss by using the “Noise Removal Effect” feature. However, it’s still hard to hear the speaker clearly, because there was a lot of echo in the hall, and I was sitting some way away from the stage. So, do you know of any way I can clean up the recording by eliminating or reducing that echo?

Any help or advice on removing that annoying echo would be greatly appreciated.

Also, did I do the correct thing by using the Noise Removal feature?


I am running Audacity version 2.0.5 on a PC running Windows 7.


Echoes cannot be removed from a recording. That’s why they do this:

Better to think of that effect as Noise “Reduction” rather than “Removal”. Removing/reducing noise from a recording will inevitably affect the sound quality of the sound that you want to keep. If Noise Removal is applied too strongly the remaining sound can become metallic / bubbly. The art is to strike a balance to reduce the unwanted hiss without noticeably affecting the remaining sound. Aiming to remove all of the hiss can sound worse than leaving some of the hiss. The “strength” of the Noise Removal effect is primarily controlled with the “Noise reduction (dB)” slider.

You hit the trifecta. Long distance, echoey room and noisy recording. You missed one: overload/clipping. Given you’re not likely to have long distance and high volume overload at the same time, so there is that.

I know it’s popular to give Tape Hiss a single proper name, but it’s not one thing. Hiss is a large collection of different pitch tones all acting randomly at the same time. It’s scientific name is “White Noise.” Because of that, Noise Reduction fails because it’s trying to remove all tones at the same time and many of them are common with the tones people use when they speak. The upshot is that Noise Reduction is trying to remove everything from the show.

Echoes are the performer’s own voice arriving at the microphone more than once. The first time is cool because that’s the direct, intentional path, but the second, third and etc are not cool because that’s the voice bouncing from the walls and arriving late. So effective echo suppression consists of software that can remove the performer from himself.

You see where I’m going with this? Noise reduction is trying to remove the whole show and echo suppression is trying to remove the performer.

Everybody loses.

And yes, they still do this for a reason…

There are other techniques you can use. You can use Effect > Noise Gate. Noise Gate tries to figure out when a voice goes quiet and it suppresses the hiss. What that usually give you is hissy voices over a velvet quiet field. There is a news broadcast that does this in place of a soundstage. It can be pretty annoying.

Some of the cellphone/speakerphone technologies do very well, but even then you can hear it working and pumping in the background trying to figure out what’s valuable and what’s not. You’ve heard it. That’s the voice whose honking and bubbling comes and goes. The worst problem with this is the person producing it never hears it and has no idea they’re doing it.


Thanks for the idea :slight_smile:

I wonder if anyone would volunteer to listen o a fragment of the recording (the first few minutes) to see if he or she has an idea how to make the thing more audio-legible?

I would be prepared to pay something if someone could apply some sort of magic to this recording.




You say:

“There are other techniques you can use. You can use Effect > Noise Gate.”

Where do I find this effect? I don’t see it on the Effects menu on my version of Audacity.



There is a Noise Gate plug-in for Audacity here:
To install Nyquist plug-ins, see: