Naked Science Forum

Non Life Sciences => Geek Speak => Topic started by: syhprum on 19/06/2010 19:44:41

Title: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: syhprum on 19/06/2010 19:44:41
Vuvuzola,s make the viewing of the world cup football a misery, they broadly peak at 233 and 466Hz are there any freely available software filters that might be used to reduce them.
Title: Re: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: RD on 19/06/2010 20:25:50
http://lifehacker.com/5566097/vuvuzela-filter-strips-droning-horns-from-world-cup-broadcasts

also ... from here (http://lifehacker.com/comment/24525724/).
Title: Re: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: syhprum on 20/06/2010 10:32:22
Thanks RD

If you want to test and adjust your filter the continuous sound of vuvuzelas is available here

http://www.vuvuzela.fm/
Title: Re: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: SeanB on 20/06/2010 12:14:45
I am 5km from the stadium, and you can hear them on match days quite easily.

Title: Re: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: RD on 20/06/2010 12:33:18
I've just had a look at the vuvuzela spectrum using Audacity (http://en.wikipedia.org/wiki/Audacity)

 [ Invalid Attachment ]

You'd have to notch out the fundamental (236Hz) and then at least next 6 harmonics to remove most of it.

(These are the main peaks on the graph).

If anyone in the crowd has an off-key vuvuzela it would get past such a notch filter.
Title: Re: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: syhprum on 20/06/2010 15:29:25
Here are Audacity analysis of the transmissions of vuvuzela FM with and without filter.
It it is only simple to include the filter in the sound channel if you have a separate set top box with sound output terminals feeding the TV if you have a modern TV with no external gadgets it becomes more difficult.
One should bear in mind that there are normally stereo outputs from the set top box the best results will be had if these are combined and the derived mono signal fed thru the filter to both channels on the TV.

Title: Re: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: RD on 20/06/2010 15:45:34
You need to use the highest sample "size" possible to see the peaks ...

 [ Invalid Attachment ]

Here the maximum size of 16384 was selected (and a logarithmic horizontal scale).
Title: Re: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: Geezer on 20/06/2010 22:57:42
Couldn't you just turn off the sound and play some funereal background music, or a loop of random crowd noises instead?

Is the commentary really that good (isn't it usually a load of piffle anyway?)
Title: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: tommya300 on 21/06/2010 20:19:58
Real-time anti noise with DSP "digital signal processing" idea.

This is just an example for the idea applied

http://www.cdxetextbook.com/fuelSys/intakeExhaust/exComp/electronicmufflers.html
Title: Is there an audio filter to remove vuvuzelas from footie broadcast audio?
Post by: nicephotog on 04/09/2010 08:39:03
Most movie players come with graphic equalisers for audio, and can be configured for streaming TV. Unless its part of the broadcast service, why not use one e.g. VLC media player and adjust to vuvuzela tastes?