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HELP NEEDED FOR A "Surround sound circuit"

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Ziddik

Member
Hello all

two weeks ago i decided to make a 5.1 amp and bought all necessary circuits such as a 7 tda2030a (2 for sub n each 1 for per channel) based power amplifier,a subwoofer filter and a preamp n now the problem i am facing is i need a surround sound decoder circuit diagram i searched for some good schematics on net but none of them seems very gud for me so if any1 of u can give me an excellent working and tested schematics for a surround sound decoder would be helpful for me besides tht i already bought a 1892ct IC based decoder circuit but it doesnt work so i changed the ic n tested th entire circuit to fix the problem sadly it ended up in a great fail n i spent lots of money for just a surround sound decoder still none of them working so pls let me know if u got a gud n working schematic.. Thanx for ur time
 

edeca

Active Member
What kind of input do you imagine having to your surround sound decoder? There are two issues which require independant solutions: the physical layer (e.g. coax or TOSlink) and then what encoding (e.g. Dolby).

I very much doubt you will find something like a Dolby decoder available without licensing.
 

Ziddik

Member
hi.. Y do dolby require a licence? All i need a gud,simple n working schematic so i can build it at home so if u already hav made a surround decoder with some gud results will be helpful for me and the input i want to connect are left n right channels because i installed a USB mp3 decoder in my amp n it has 2 channels out (STEREO).. thanx
 

edeca

Active Member
OK, so you have a stereo input and you want a set of 5.1 speakers. So you need to decide how you are going to expand the input (2 channels) into the output (6 channels). Three of these are fairly easy, your left and right go to front left and right, whatever the sub threshold is will go to the sub (e.g. below 20KHz).

What would you like to send to the other 3 channels? Generally you would not listen to music in surround sound, as it is designed for stereo.

Dolby require a license for their technology, which is arguably the most widely used, because they invented it and patented it. This will also apply to Dolby Pro Logic II, which encodes a surround sound signal in a stereo stream.
 
Can't you sort out the frequencies? For example, I'd have acoustic instruments like a symphony orchestra biased toward the surrounds, focusing the guitar and vocals toward the main speakers. Maybe the guitars higher harmonics could go through the surrounds to really slice through the air. Or rely on something like a reverb/chorus to "create space".

Interesting to see what you come up with. Good luck
 

edeca

Active Member
Sure, you could do all these things in theory. Many home A/V amps will include signal processing to do this, mine has a number which "expand" a stereo source into surround sound. You cannot simply buy chips to do this though.

What Ziddik needs to tell us is what he would like, then someone can help him work on it further.
 
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