3 way speaker build/ crossover questions

[chadavro]

Hi all I'm thinking of re-doing some old speakers and I have some questions about the crossover / impedance issues. First of all the speakers I'm planning on using are as follows (this is per enclosure)

2- Dayton RS225S-8 8" woofers
1- Dayton RS52AN-8 2" midrange
1-Dayton RS28A-4 1-1/8" tweeter
1- Dayton XO3W-700/5.6K 3-Way Crossover 700/5,600 Hz

See the problem is the tweeter is 4 Ohm's and the crossover says you need to use an 8 ohm tweeter. What will this do to sound quality / crossover points etc.... Also what would be the final impedance of the speaker system? Don't really know anything about crossovers

Also is if this config would work anyone recommend using L-pads because from what I've been reading people recommend using them for that midrange and possibly that tweeter too.

How do you guys think this would sound in a sealed enclosure with around 2.4 cubic feet of volume?

Thanks in advance for all your help!!!!!

[mistertwister]

IMO this crossover is inappropriate for drivers selected.
you'll need at least add notch filters for woofers and midrange.
and for 5.6k crossover RS28A is overkill.
If you must use this crossover, look for poly cone woofers(less cone breakup),
soft dome mid and some cheap buyout tweeter.

[fourdegrees]

You would be much better off going with a proven design like the Khanspires, RS TMWW or RS 3-ways, if you want to use the Dayton RS drivers.

[Paul Carmody]

Spend a few minutes doing some reading. It should help your understanding. It's written a bit tongue-in-cheek, but the answers are reliable:
http://undefinition.googlepages.com/diy-mfaq

As to why people will suggest you build a proven design:
http://undefinition.googlepages.com/...-provendesigns

As for your impedance question, well it's really immaterial. This explains it:
http://undefinition.googlepages.com/...iverimpedances

[johnastockman]

Paul is very humble, but his pages on MFAQ's of DIY speakers that he linked to are well written and very informative. I wish I had that advice when I started out rebuilding old speakers and making my own. The end results I got would've been much more satisfying than what I achieved using those pre-made XO's and the textbook formulas I tried to make work. Neither the pre-mades or the textbook XO's even approached marginal SQ...awful was more like it. It wasn't until I found this forum (and the original Madisound forum) over 9 years ago, that I was made aware of why those types of XO's don't work well. There are proven, tested and built designs that use those drivers, with help available along the way if you have any ?'s. Fourdegrees linked to some VERY good designs using the RS series. A good XO design for any given combo of drivers requires measurements and a way to use those measurements to come up with a design/topology that will compliment the chosen drivers. No driver is a constant 4 or 8 ohms, as the impedance varies with frequency. And that's just one of the variable parameters you have to consider when getting the XO right. Fixed-number calculations (textbook and pre-mades) are woefully inadequate when it comes to XO's. Paul's pages will help a lot, so check 'em out and I'm sure you'll have more questions, which the talented pool of gents here will be happy to answer...even me, if it falls into an area that I have experience with. Good luck!

John A.

[scottq]

There are lots of very friendly people on the forum... one that's close enough with some measurement equipment might even measure them for you and generate a crossover mated for your application after you build your enclosures.

The other option would be to pay some people in the DIY community - several offer their services for custom design work. And, of course, there are numerous "published" designs on the various DIY Contest pages.

And a 3rd option would be to pick out some drivers that Madisound stocks and have them design a crossover in LEAP for you. This is probably the most "economical" method that will produce decent results and still give you flexibility on driver choices (as long as they sell them - an obvious disadvantage if you're dead set on using the Dayton drivers).

Nonetheless, the forum here is full of really friendly and helpful people that want nothing more than for you to succeed. So, don't take the criticism of people telling you not to use "out of the box" crossovers to offense - they're just trying to save you time, effort, and money :-).

Good luck!