Dayton or HiVi

[Wheels]

So sometimes you gotta just start a project, but I want to make sure I'm picking out drivers that will play well together. I'd like to use the Dayton ND20FB tweeter, but I am having a harder time picking out a woofer to go with it. I can't decide between the Dayton RS100, the HiVi B4N, or some other recommendations similar to those, (peerless, but I'm having a hard time finding datasheets for those). I really don't want to spend a lot on this, mainly just wanting the experience and know the speakers are going to behave at least halfway predictable. I'm thinking tops $35 on a single woofer, I'd rather keep it around $20.

I'm worried about the freq spike at 3khz with the HiVi, and I'm worried about low end distortion with the Dayton, based on Zaphs measurements.

So since the hard part is designing a crossover, and I'm thinking a cheap MTM computer speaker type project would be a good enough first project. I plan on having to use a sub with them to cover the whole spectrum, but I'd like them to be respectable down to at least 80hz or so. Since I'm going to use them as computer speaker, I'd like to keep the woofer to 4", unless there is just a much better recommendation up to 6"

And I'm not dead set on the Dayton ND20 tweeter, but It looked to be a good performer both freq response and distortion wise for the money. (Thanks Nathan for the tip on that one)

Thanks in advance for the advice guys
Wheels

[Undefinition]

If this is your first crossover design, I have a few suggestions.

First, the ND20 is a pretty tricky tweeter to work with, especially when paired with low-sensitivity woofers. I'd recommend something a little more well-behaved and robust. The Dayton ND28F is excellent for this purpose.

Second, I don't recommend a metal-coned driver for a first project. They tend to have a breakup mode that usually requires a notch filter. (If you don't use a notch filter, you'll be wrestling with a lot of extra sibilance) So when looking for a woofer, look at its FR graph; try to choose something that looks generally flat, or at least doesn't have a giant spike (paper and poly cones are often good places to look). I'm not against notch filters--I use them all the time. But designing a crossover is enough of a juggling act as it is. To add a notch filter is like someone tossing you a miniature poodle at the same time.

I don't want to discourage you at all. I just want to help you have a successful project!

[fbov]

...designing a crossover is enough of a juggling act as it is. To add a notch filter is like someone tossing you a miniature poodle at the same time....

Never thought of this in circus terms before....

And you could fill a thread with catchy replies - what's the matter, you out of regular poodles?

Or not.

Have fun,
Frank

[Wheels]

Undef, thats not discouragement to me. I was wanting to make sure I had some drivers that wouldn't discourage me because I wasn't able to make them sound decent due to odd xover reqs.

[BOBinGA]

Also, if you are trying to get below 100 hz with one of those woofers, you have to use a ported box. And a ported box will be bigger than those little 4x4x4 cubes many of us have for computer speakers. If a slightly larger box is OK, then either the RS100 or the HiVi B4N will work well.

Paul's Overnight Sensations are close to what you are looking for and he has a very good write up on them that you can use as a guide to designing a crossover. I also posted an RS100/ND20FA design here that also shows many crossover considerations:

http://www.htguide.com/forum/showthread.php4?t=38222

Neither Paul's nor my design were specifically designed for near field, table top computer use. You will most likely need to reduce the baffle step on either one to fit your needs.

-Bob

[Ray_D]

If you want a woofer under $20 look at Zaph's ZBM4. I have built about 20 of these and they are excellent. I have a pair as my computer speakers. I would recommend the cast frame version of the woofer, MCM55-3853, rather than the stamped version which can flex if not mounted carefully. The cast frame version was not out when John did that design. You could use a different tweeter and stay with his box design if you wanted to something slightly different.

http://www.zaphaudio.com/ZBM4.html

Good Luck

Ray