Karoke

[magnetra]

I want to design a karaoke system. Here's what I've thought,
I'll take input from a diskman, I'll eliminate the vocal part and also I'll take iput from mic (vocals), mix the resulting signals and playback.
Now,i want to know, how best can i eliminate vocals from diskman input...would a bandstop filter do????. I'll be working in monophonic mode only.
Regds
Magnetra

 

[Dr.EM]

Nope, a filter alone won't remove the vocal without seriously effecting the sound quality. If you are doing this in mono only, you limit the possiblility of effectively removing a vocal track. I can suggest how this is done with a stereo signal, and there are ready made units that can do it too, but with mono its a different matter. For instance, electric guitar sound, especially an overdriven one will invariably have harmonics present in the same area as the vocal track, if you try to remove the vocals with a simple, or even quite coplex parametric filtering system, you will upset the guitars sound.

 

[mstechca]

since sound pitch is dependent on frequency, you will need to incorporate some frequency comparison circuits to filter out which sounds you want. You will need to determine the frequency of every music background you use in every combination, and then only allow those frequencies to go through. At the absolute minimum, a band-pass filter will only work for one frequency.

Because you are filtering out voice, the task may be difficult as each voice presents different frequencies to filter out, so simple filters cannot pull it off.

To start, go with some phase lock loops and then you can use an LED to determine when certain sounds are played.

 

[Nigel Goodwin]

'mstechca' is talking total rubbish!, vocal removal is fairly simple, PROVIDING THE VOCAL IS IN THE CENTRE OF THE STEREO IMAGE. There are many commercial units and simple circuits to cancel such a vocal out, but it depends entirely on the centre accuracy of the recording.

My Behringer mixer/amplifier incorporates such a function, and it works extremely well - BUT ONLY ON THE CORRECT TYPE OF CD'S.

Karaoke CD's are special recordings, with the vocals left out - no cancelling scheme will sound anywhere near as good!.

 

[Dr.EM]

Yep, well, there you go. Old 70s recordings where they have gone wild with stereo will not work well, as often the vocal is panned to one side. What will work well though is pop music, which is probably quite appropriate for karaoke :lol: . But yeah, your best bet is to get something like this:

**broken link removed**

Your diskmans output is sure to be stereo, so I can't see why it should be too big a problem. You'll also need a simple mixer, that might be cheaper to build yourself.