[John_M]

Does anyone know of a graphic equalizer which can completely eliminate certain frequencies?

I'm trying to listen to some recorded lectures which are muffled by some background noise (air conditioning and other stuff) -I want to completely delete all frequencies, apart from a couple in the middle so I can hear the people speaking.

I asked this on the computers forum but I need to know the answer and there's about 3 people on there compared to about 1000 on here.

 

[OtterMarc]

John,

What medium are you using? Cassette tape, portable digital recorder, MP3?

External equalizers will rarely drop a zone more than about 20db, though that's usually enough. Music shops carry them and will rent them, but likely a computer solution exists.

On your computer in MS Media player, you'll find an equalizer that may work enough for you. Make sure "averaging" is turned off, else you drop a wide band, not the narrow one you want. You might not have to convert files to .wav to get an adequate result.

More advanced options come with the softwares that come with the better Soundblaster sound cards. All that follows only works on wave files. Wavelab Lite, and the recording software Cubasis that come with some audigy cards has parametric equalizers built-in or downloadable.

The emu sound cards come with software parametric equalisers. This permits you to find the specific frequency affected by the noise, the bandwidth, and the amount of attenuation or gain to best cancel it without loosing the voices you still want to hear.

Failing that, I'd try cnet and zdnet for freeware audio recoding programs like Audacity. You should find all you need in there, though it may take a bit of time to figure it out.

If you're a linux fan, there's a version of linux all built up for musicians called musix, I think. You'd find all the tools you need there as well. Hardware compatibility becomes the issue.

Hope that helps you solve your problem

.
Marc

 

[craiglester]

do you have a section of the recording with the background noise and no talking? If you do you could try a run through the soundforge noise reduction filter.
Works well on specific noise patterns

there may be one available for free in audacity also, but i haven't used that myself.

 

[jilgiljongiljing]

if you can get your hands on Steinberg Wavelab or the any audio editing software that has a band pass filter. You should be able to find a band which captures the voice clearly.
This attenuates the rest of the frequencies to a very large extent, hence the voice might not sound the same as the source, but you can significantly reduce background noises and hiss.
Graphic EQ is not going to do you much help, but make sure you reduce the other frequencies instead of increasing the frequency that is centered around the voice. always go -db and not +db especially if you are using software EQ