Okay, I have somewhat of an insane request but I wanna create a 7.1 system for my pc straight off the Motherboard all from scratch... except the actual cones of course. I have 6 jacks on my mobo and I wanna make a sort of reciever and sub enclosure with the amp for the sub in the sub enclosure and if anyone knows of any good speakers for each channel.

I guess what I am asking is what parts will I need to fabricate and if you happen to have any advise for speaker enclosures.

The channels of the jacks from the mobo are,

Center Bass(since I've never set it up I don't know if this is the Center speaker and the sub, think so)
side speakers
rear speakers
Front speakers
mic
line in

One other thing is I'd like to make the plugs matching these jacks centralize into one cable and one jack into the "receiver" I was thinking some kind of fifteen pin connector, or would this be a bad idea because of bleed over or would shielding help.

;side note I'm not really picky about sound as long as it is surround sound just a small project.

You're right about the center/bass. The 2 channels on that jack are for the center speaker, and the subwoofer. Usually you can swap the two with the sound drivers, however, I believe that the tip channel is the center speaker by default.

For the cable, all grounds are common. So for 7.1, you will need 8 signal conductors, and 1 ground. A shield would also be a good idea, since this signal needs to be fed into an amplifier. If the amplifier can be close to the PC, this helps a lot.

I made a cable for 5.1 using an ethernet cable. (8 conductor) I use 6 lines for signal, and 2 for ground. The 2 are tied together, and since they're earthed at the amplifier end, they double as a shield. It works reasonably well, I don't get much noise from the speakers, though it's not perfect. It was, however, cheap and effective. It extends the speaker jacks by a good 15 feet. Given that, you could make an adapter using a 9 pin serial cable to extend your 7.1 sound to your amplifier. If you get a good serial cable, it should already be shielded, at lest well enough for analog audio.

For the amplifier, I guess it depends on your tastes in power. You could use a series of cheap stereo receivers, second hand, eBay or whatever. You set the volume once to get the sound balance that you want, then the master volume control ccomes from the PC. Each receiver can then deal with 2 speakers, so you'd use one stereo set for front, one for side, and one for rear. Center/subwoofer would be a bit trickier, but if the receiver has a set of A/B speakers you could connect the sub to the "A" speakers, which usually have more power, and the center channel to the "B" speaker. Use the balance control to fine-tune the relation between the center channel and the sub. Okay, so you'd have 4 receivers piled up, but it's probably still cheaper than the cheapest 7.1 receiver out there which can take discrete analogue inputs. Of course companies like Logitech make speaker sets that work for exactly this purpose, but if the idea is for DIY speakers, then you need amplifiers.

You can also visit places like Elliot Sound Productions for building your own set of DIY amplifiers, but the cheap receivers is probably less expensive, and faster. (Even if you build your own amps, the PSUs and heat sinks in the cheap receivers can be very handy.)

For speakers, I've never been a fan of the standard MTM (Mid - Tweeter - Mid) center channel, but it does work well for a lot of people, and does tend to fit well under or over a screen. There are many ways to make a speaker enclosure, and it will depend on what kind of sound you like.

Okay I think what, I'm gonna do is build the Hi-Fi Preamplifier shown here(http://sound.westhost.com/project97.htm) to break the rust off of my cogs.... since to be honest I have no audio experience but I think what I am going for is something like this 7.1 channel Hi-Fi microprocessor/PC controlled Preamp(http://www.electro-dan.co.uk/preamp/construction.html) yeah I know it's way beyond me.. but hey I said it was insane

Any idea's for enclosures and speakers

Oh and just my learning curve anyone know any good projects in between these two... some kind of babystep if you will.

Not sure what you're budget is, but I'm just about finished making a pair of Zaph's single-driver speakers based on the inexpensive Hi-Vi B3S. They sound very nice for the price and are pretty simple. Throw in a DIY sub and you'd have a system that bested just about any HTIB setup around.

FWIW...

For me, it would depend on what you have in terms of budget, tools and carpentry skills.

I'm not, for example, going to recommend that you build a bandpass subwoofer if your skills are barely adequate for a sealed box, or you are going to try to do it all with a dremel!

What size room are you working in? What kind of amplifier power are you planning on? Do you want something that shakes the foundations of the neighboring apartment buildings? (There's a really impressive TL sub detailed around here somewhere...) Do you want floor standing speakers? How much room fot speaker cabinets can you spare?

These are all vital questions for design.

I've built a subwoofer system for one friend where the sub cabinet measures 36" by 48" by 13.5". He's powering that with about 150W of amplifier, and it knocks pictures off of the wall. I've built another that measures 13.5" by 13.5" by 13.5", is powered with 450W of amplifier and isn't nearly as loud, but it does go VERY low.

For speakers, I have made cabinets which are up to 54" tall by 24" wide, each one housing a 15" woofer, and I've made some as small as 8" tall by 6" wide, housing a 4" woofer and 1" tweeter.

The conventional box for speakers works very well, and most midrange and up speakers aren't very fussy about the size of the enclosure that they're in, or even if that enclosure is sealed.

More important by far is the choice of speaker elements, and the crossover network that you choose.

Woofers ARE picky about the enclosure sizes and types that you put them in, of course, The lower the woofer is intended to play, the pickier it is.

Crossovers play a vital role in how good a speaker system sounds.

I like active crossovers when I can get them, but with a 7.1 system, particularly if you're building your own pre-amp and volume control you're already dealing with at least 8 channels. Adding in more channels for mid/tweeter active networks is kind of a scary proposition. (By the way, that pre-amp on the ESP website is a 2 channel configuration, you'll need to build a total of 4 of them in order to work with a 7.1 system.)

For passive crossovers, I like at least a second order (12dB/octave) crossover, and I like to (if possible) have a zoebel netwrok in place to keep the overall impedance curve under control. This makes for a more complicated crossover, and you have to pay attention to the actual values of your components (not just the RATED values) in order to do it well. Inductors and capacitors are particulary hard to get good tolerance values on without spending a premium, so I tend to buy a bunch of extras and measure them. In a batch you can usually get some which are very close to rated, or at least you can find ones that are very close to the same.

You will at least need a 2 way crossover between the mid/tweet, but you might want a 3 way crosover for woofer/mid/tweet, depending on your choice of cones.

My personal preferences for speaker ranges are that the mid shoud be able to play everything from about 300 Hz to about 4,000Hz. This is a bit beyond the primary range of the human voice, and the slightest crossover artefact in this area will be easily audible, since that's where the ear is most sensitive. (Sometimes 3,500 Hz as an upper limit makes the speaker elements easier to source, and I figure that's fine.)

A mid that can play down to about 80Hz is a bonus, and works well for 2 way systems + subwoofer.

Hmm to answer some questions My budget doesn't really matter, but I'm not really concerned about anything to ostentatious. This is just a small project to get me back into electronics, before I decide that I wanna go back to school for it. So really I'm not a minimum budget person but I wanna DIY every part possible of this.

I worked in a wood shop so I can achieve an airtight seal np.. The speaker size I was looking for was someting like 2"-3" for the 2.0 part just enough to take the place of my current factory ones and not be to bulky on my desk. And I was thinking about using walnut for my boxes... is this a good wood for this? I dislike and detest mdf or anything of the sort.

Yeah the 2.0 preamp is a stepping stone I want to take, I figured I could use those in later plans, I didn't know if I should go 2.1 or 4.0 next

I'm sorry I kinda turned this into a 2.0 topic but as I said that is just temporary, till I get comfortable with what I can do. A custom(and hopefully someday digital interfaced) 7.1 system is still my goal here.

I should be able to start building the 2.0 preamp within the next few days, deciding weather I should build the board or buy it, I know it's just more for me to stack on an already full kids size plate, but why stop now I figure I'll learn more from mapping my own board(or fail till I do).

I'll try to post some pics when I start, and they will be completely open for criticism.

For what it's worth, I have several of Rod Elliot's boards, and the quality of each and every one of them is nothing short of superb. I think that I managed a slightly smaller board for ONE project once, but I could only do that because I was actually deleting features. I do strongly recommend it, plus once you buy boards, you get access into a private part of the website with construction tips, which also includes projects that you didn't buy.

Rod also has a hi-fi PC speaker kit that I can recommend. It consists of the pre-amp, a P19 and a P3a amp set, with a P09 crossover. The result of that combination is a really nice bi-amped setup which can put out a lot of juice, and be very clear.

I also dislike MDF, but it has a huge advantage in speaker cabinets in that it has next to zero resonance. As such, I end up using a lot of it.

Any hardwood can be used to make a good speaker cabinet, but you do have to be careful about bracing. If you don't then the wood's resonance will start to play a factor. For small speakers, like the 2.0 setup that you're talking about this isn't going to be as big a deal, but you will be somewhat limited in low range with a 3" woofer. I'd figure that the next step after that would probably be to go either 2.1 or 3.1

Awesome thanks man I thought you just got some extra documentation (which I do dearly need), but I didn't know about the other part of the website... just for future reference is that for a limited time that you have the access? Either way I will buy his boards, it sounds like the most efficient way to go. This is gonna push my project off a little bit but it'll give me time to get components and enclosures worked out.

Getting my existing collection of components organized has been a nightmare, I abandoned it for 4 years and moved a handful of times so things are completely out of order. Even still I think I might have to order or radio shack nearly everything for this. I kind of want to give Jameco a shot, is this a good vendor for small projects is there anything in the way of charges that would offset what I see as low prices.

About the walnut enclosures, I heard square angles would be a bad thing as far as resonance, the bracing would be there just to prevent resonance like in a v shape inside right? or is that a baffle?

So just to fulfill the topic I think this is gonna progress as 2.1, 3.1(probably before I even get 2.1 closed up) then adding the side and rear channels, then working in some of the controls stated in a previous post, there that's my game plan bringing me to a 7.1 system.

I don't know how to thank you supra you've helped a lot just in the concept, if there's anything to add feel free I appreciate every bit of it.

Ok I looked at these after you posted it, but never replied. I love the rounded edges, and I am pretty sure I'll go with these I think they will fit nicely on my desk. So now I just need to find a walnut lumber dealer... Shipping is killer on small amounts of wood.

Try Rockler. Free shipping on orders over $50 (see their homepage for the code) and they will likely have other things you might need for the project.

If it were me, I might try something other than walnut though. That's not an easy wood to work with, and is murder on things like router bits, etc. A happy medium between mdf and hardwood is something like baltic birch plywood. Finishes nicely but is not as resonant as wood, I don't think.

Oh, and in case you desire something a little bigger than Zaph's B3S design, both Madisound and PartsExpress are currently running "recession buster" specials on 2-way kits with pre-wired crossovers. Both are absolutely fantastic deals.

As far as I know the access is perpetual. I bought my first boards 4 years ago, and the code that I got for access still works. I bought another set later as well, but it's been a couple of years.

Right angles are somewhat problematic in speaker enclosures, but not too bad, particularly not for midrange. It's far more important to have the interior dimensions not be the same in multiple dimensions (Unless that dimension is less than 1/6 the wavelength of the highest frequency that the speaker will play.) Baffling is different from bracing. Bracing is basically connecting something to the middle areas of the panel so that it cannot vibrate with the sound. I generally make my braces attatch from one panel to an adjacent panel at either 45 or 30/60 degrees. This is enough to keep down the cabinet resonance. When you knock on the side of the speaker cabinet you don't want to hear a sharp sound, but rather a dull "clunk".

Baffling is used to break up the interior of the speaker cabinet. For example, you probably don't want your midrange sharing airspace with a woofer, since the internal pressure from the woofer will distort the midrange... Though you have to be fairly picky about your sound and be playing at least moderately loud before the effects become apparent. -- I'm picky enough.