Help designing my first DIY project

[zman27]

I am new to the whole DIY scene and I was thinking about trying to design my first project, but need a little help getting started. I am a college student on a tight budget so I am not expecting anything spectacular or mind blowing, just a decent pair of speakers for a good price, with the added benefit of getting to build them. I have gotten many suggestions from other people saying that I should start with a kit/a proven design, but I was looking and didn't really find anything that peaked my interest or fulfilled what I was looking for.

I was looking to build a three-way speakers about 20"-30" tall. I am looking to spend ~$100-$120 for speaker/crossover components. I realize that I wont get amazing quality for that money, and I am fine with that. The speakers will be used in many varying environments/rooms over the next few years so something that isn't very specialized would be best.

If you guys can provide any help/direction/designs it would be greatly appreciated.

Also, I have a question about modifying a pair of speakers that is in my current system:
My system currently is:

2x Cambridge Soundworks M-55 Bookshelves
1x Bose Acoustimass Center
2x Technics SB-LX7 Floorstanding 3-way speakers
1x Sony WM-250 100Watt Subwoofer

Would it be a good idea/an improvement to swap out some of the speakers on the Technics? Does anyone have experience with these speakers and have any suggestions of what I can do to them to make them a bit better?

Once again, any help is appreciated. I'm sorry for my inexperience, I am trying to get into the DIY speaker hobby and am trying to use this as a starting/jumping in point.

[ThomasW]

$100-$120 per speaker or per pair?

You should consider a 2-way, 3-ways double the crossover cost.

To reinforce what others have said, unless you have a spare several hundred bucks to spend on test equipment, it's a good idea to build someone's proven designs.

[zman27]

I was looking to spend $100-$120 on parts (Not including building materials) per pair. I am not looking for amazing quality speakers that will make people's jaws drop. I am just looking to build a pair that sounds decent. I dont really see why the $100s of dollars in testing equipment is necessary if I am not looking for the utmost quality. I am sure that I will be fine just using the theoretical calculations/suggested sizes even if there is a little drop in quality when translated to real life. What I was looking at using are these:
Tweeter: http://www.parts-express.com/pe/psho...number=270-155
Midrange: http://www.parts-express.com/pe/show...number=280-250
Woofer: http://www.parts-express.com/pe/psho...number=290-305
Crossover: http://www.parts-express.com/pe/psho...number=260-210

I know its not advisable to use a pre-built crossover because it won't fit what I am doing exactly, but for these speakers would it work? I realize that I am going about this process a bit backwards, but I am trying to save money while still building it myself. I am open to trying a proven design, but I haven't been able to find anything that is what I am looking for in my price range.

[Operandi]

$100-120 is pretty tough, you would have a lot more options in the $200 range, for though $120 a two-way is really the only viable option.

Generic crossovers are a bad idea, the end result would be significantly less than "decent".

I'm not sure what the price works out to but take a look at the vented TriTrix MTM in the Mission Accomplished forum. It's a very nice speaker that should be close to your budget.

Another option would be Madisound's Recession Buster kit, you could pair with a DIY sub down the road to fill in the bottom end.

[fbov]

You might consider these:

http://www.madisound.com/catalog/product_info.php?products_id=8525

$75 for the pair with binding posts, delivered. Well respected drivers, a decent crossover from all reports and a good starting place if, like me, you want to learn how to play with XO design. You'll find a lot of people talking about them right now.

HAve fun,
Frank

[ThomasW]

I am sure that I will be fine just using the theoretical calculations/suggested sizes even if there is a little drop in quality when translated to real life.

Those will work fine if you're building a low cost car audio system. Designing a home audio system isn't like ordering Chinese food where you randomly choose items from column A or B. Instead there needs to be a careful blending of components matched and designed to work as a 'system', otherwise it won't sound good.

I am open to trying a proven design, but I haven't been able to find anything that is what I am looking for in my price range.

Your options are

1) change your expectations, a good sounding 3-way for $65 is a pipe-dream
2) change your budget.

FWIW, it's likely what you're proposing to buy and build, won't sound as good as what you have now...

[zman27]

I actually had a question about the SB-LX7 I have now. One of them has a busted tweeter; It still works most of the time but other times it can be very grating. I bought them second hand and it looks like someone tried to patch the damaged tweeter. What is the best way to determine a good replacement for the tweeter? And I am assuming that it would be best to replace both of the tweeters for matching purposes?

I will look at the kits/designs you suggested. I will also check and see if I can free up a bit more budget. What would my options be if I pushed it up to around $150-$170, or even up to $200-$250?