need some help picking some 3-ways

[adolphe]

Hey all, I've decided to dive into the world of DIY speakers. I was originally planning on just buying new speakers for my setup, but due to the budget constraints, and some free time, I figured it would be much more interesting to try my hand at building them myself.

I've started doing my research and stuff, but I've come to a real road block in trying to determine what drivers to use. I've decided I want to go with a 3-way system. These will be full range (or basically full range), with no additional subwoofers used. They will be driven with 75W/channel. I really don't know where to start other than setting a budget. I would not like to spend more than $200 on drivers I don't think, but I may become flexible if the added performance will be substantial. Can I buy 6 good drivers for this amount, or should I look at increasing my budget, or going with a more simple 2-way setup? I would really like to do a 3-way setup if I can though.

So could you guys give me some suggestions on some drivers to look at, and maybe some tips on what specs to specifically look at when determining a "good driver" without doing a listening test???

For a place to start, I was thinking a 7" woofer, 4" mid-range, and a silk/paper/fabric tweeter, but I really don't know. Open to lots of suggestions here.

Oh, and I'll be building my own box and passive crossovers as well.

[morbo]

1st suggestion: If you've never built a DIY speaker, and want high quality results the first time out, go with a respected kit or design. It may seem limiting, but in reality you WILL learn a great deal more than you expect, AND end up with something that clearly justifies the expense and lights the fires of DIY addiction

2nd suggestion: If you plan on designing your own crossover, invest in some measurement equipment/software and get a copy of speaker workshop (free design software). Without measurement equipment and modelling software, it is going to be almost impossible to design a great sounding 3 way speaker from scratch.

3rd suggestion: If you only have $200 for drivers and XO parts, a 3 way may be a bit ambitious. And if you do decide to do a 3 way, I would reconsider the drivers - 7" woofer & 1" tweeter would likely work just as well or better in a 2way. Personally, I would go to an 8 or 10" woofer and probably a 3/4" tweeter if there's a good one in your pricerange.

[Bare]

Suggest something From Madisound or Dayton.. they have lotsa inexpensive 'startewr' setups.. some pretty darn good.
Do remember that a Retail Speaker system is 20% for the manufactuere and the rest to middlemen.. Use yr Calculator to determine just how inexpensive the parts of a $2000 speaker System actually are :-)
Do try and avoid a 3 way.. and Gawd Forbid a 4 way .. (Sub)
Full range is 1! driver . More drivers simply equals more problems.

[adolphe]

Thanks for the advice about going the kit route. I've seen that suggested many times to the beginners here, but what I've never really seen is an explanation of what you mean by a kit. Is it a common design that many people have done before, or a box/driver/crossover product that I buy from a dealer and then build myself? Or is it both? If it's the first, is there a specific database of proven kits that I can look at with detailed descriptions?

As for the measurement equipment, I realize this is important. My roommate is in 4th year electrical and has access to all the fourth year labs here at Waterloo and he said he'd give me a hand with the crossover.

Like I said about the drivers, I don't mind spending more if I'll see the benefits in the final product. Would going to a MTM be a good idea if I wanted something a little more?

[inertial]

(sorry for my english)
Hi adolphe,
why not clone a "serious" minimonitor 2 way, to start?
For example Sonus Faber Minima, ( I belive 15000 pairs sold)
a seas 11fgx standard , a dynaudio D28 (very close to D28-SF)
1 coil ,1cap, 1 resistor, 6litres cabinet,end.
Bass? Maybe enough , maybe not (you can add a sub if necessary)but it sounds !
IMHO I think a very good experience to "understand" .
If you are interest look at Stereophile archives.
regards

[joensd]

what you mean by a kit.

If you go by a kit you don´t have to choose the drivers, cabinet and most important design the crossover which can get overwhelming for a newbie unless you are prepared to be VERY patient and invest lots of your time listening, simulating, listening, measuring......

If you want a kit finally and your money´s worth try to get a listen of it first (shop or local DIYers)
Remember everybody´s got a different taste...

Here´s one maybe :
http://www.speakerbuilder.net/web_fi...a/lyramain.htm

greets

[bogoes]

For a 3-way in that price range I would recommend the previously mentioned Lyra, or the Jubilee from Parts Express. Both are well-respected designs. From there I think you're going to pick up a lot more cost before gaining any real ground, but you might want to check out the D27 Veritas - same designer as the Lyra's in a massive dual 10" design - using a budget tweeter.

If you're just looking for good and full sound, with good bass, and you're willing to consider 2-ways (which I would recommend), definately look at Dave Tenney's Dayton 8 MTMs. Definitely no sub needed here, and apparently they sound great - people love those 8" Daytons.

Jubilee
Dayton 8 MTM
D27 Veritas

Good luck.

[adolphe]

Thanks for all the info guys. I've done some more searching, and I think I like the idea of cloning some else's design, or atleast doing my own slight variation on it. It gives a good place to start and something to compare my results to I suppose. Now I just have to keep searching until I find the right design. So far two that I like are:
http://www.tnt-audio.com/clinica/nues_e.html
http://www.speakerbuilding.com/content/1028/

I'm an engineering student, so by nature I like to tweak/tune/fiddle, and I would say I have a decent foundation of theory, so I don't mind diving into stuff like cabinet and crossover design. But yes I do agree that I think I might try to stay as close as possible to other people's designs.

One question that I've come up with is, what's a good relative db level in the low frequencies (sub-70Hz or so) when not using a sub? What I mean is, when you look at a SPL vs Freq graph from 20Hz-20kHz, and the SPL begins to trail off below 70Hz (for example, and where above 70Hz is flat at some db level), at what delta-db will you start to say "this needs a sub-woofer"? Or does that have a completely subjective answer?

[Timn8ter]

For most music if you can achieve bass response of 40Hz that will be low enough. High response will depend on how good your hearing is. If you're young and haven't damaged your hearing yet you'll probably want something that can hit 20kHz.

[adolphe]

Wow, I really like the Dayton 8's. I think I'll likely do those, or something very very similar.

I have a question about MTM's now though. What is accomplished by using this arrangement vs going with TMM? Also, neglecting the added crossover complexity, what would be lost by adding a mid-range in there, and rearranging it to a TMWW type config?

It's looking like the Dayton 8" and silk dome tweeter are likely the drivers for my budget and performance goals. My only hesitation now is the slight loss in mid-range detail by going with the Dayton 8 config.