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kanifee 10th September 2008 09:02 PM

surround sound.
Is it possible really and how hard is it to achieve?

Redshift187 10th September 2008 09:26 PM

Anything is possible given enough time and money. As far as difficulty, it depends on what exactly you want to do.

What's the source? 5 discrete analog channels, or some sort of encoded digital?

kanifee 10th September 2008 09:52 PM

hmm, if i was using a pc soundcard i suppose this would make the thing a darn sight easier, what sort of effort would be needed to work with encoded digital signals?

llmobll 11th September 2008 04:23 AM

Well i'm actually work on a surround Gainclone right now, I'm using a computer as source, so this grealy simplfies a few things. I'm going for a 6 channel amp, with the possibliliy of adding a front center channel in the future.

A few things you need to consider:

1. The amount of inputs: this makes things either increasingly difficult or very very simple. I believe I found an elegant (cheap) way of having 3 selectable inputs: mp3 (stereo), input 2 (stereo), and 6 channel input from my sound card. (i'm working in a switch that will make the stereo inputs feed all 6 channels when i want them too)

2. Power. Depending on the size of speakers, and also their quality, this will make the cost of your project go up or down. I'm probably going to run 3 torodial tranformers, 300VA for rear and side, and 250VA for the fronts. This will definitely give me enough juice without having to go to very big transformers. (i'm not looking to rock the neighborhood, but i still want some kick)

These are the biggest hurdles i'm come accross so far. I'm going to post my setup when i'm done. Though i'm taking my time, I enjoy the journey as much as the destination.


diarav 11th September 2008 06:02 AM


I am also working on a 6 channel amp now. This has about 8 input sources (DVD player - 6 channel input, 4 aux - stereo, built in tape - stereo, built in ipod dock - stereo, built in fm - stereo). Selection is using CD4066 and CD4017 ICs.

For stereo sources there will be a switch to convert to 5.1 surround using the hafler matrix circuit from Rod Elliot's site.

I am using LM3886 chip amps. Still working on the Power supply.

Like llmobll I am also taking my time to get this through.

AndrewT 11th September 2008 12:02 PM

I don't think us amateurs can use the digitally encoded surround sound signal. I believe the decoding/demultiplexing circuits are restricted to OEM manufacturers.
You have to use proprietary hardware to generate the analogue channels and then work with the separate channels after that.
5.1=6channel. i.e. two rears, two fronts, centre and bass. No side channels in a 6channel signal.

pacificblue 11th September 2008 01:41 PM

Exactly. The ESP project is from the times of analog surround. The actual surround formats are all digital, and the decoding takes place on the digital level.

There was a thread not long ago, where somebody had a contact with sombody at a manufacturer, where they build the decoder ICs. It took him quite some effort to get one for his private use. Those manufacturers have no interest and no need to sell to anybody but OEMs.

There is also hardly any market and thus no offers for decoder/preamplifiers, except for very few, very expensive ones. So there is next to no chance to diy a decent and up-to-date surround amplifier for a diy price.

kanifee 11th September 2008 11:14 PM

i guess the best i can hope for then is a six channal amp with a high end multichannal sound card and strictly only oc as the movie source, would the results still be of a high enough uality to make it worth while?

llmobll 12th September 2008 05:38 AM


Originally posted by kanifee
i guess the best i can hope for then is a six channal amp with a high end multichannal sound card and strictly only oc as the movie source, would the results still be of a high enough uality to make it worth while?

Depends on the source. The software will also come into play if you go that route.

Even an X-FI pro with new opamps... would be worth wild. Depends what you're upgrading from.

My current project: x-fi pro with new opamps, 6 channel surround. (sorry no sub, i live in an apartment) and quality speakers. Anything more than this, and i think you need to spend $2K+.


Redshift187 12th September 2008 09:38 AM

What about a DVD player with 6 analogue outputs?

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