I can't decide what I want to build :-/

[Jim85IROC]

I'm getting ready to spend some of my tax return money on some speakers.

My plan for a while has been to build the Usher CP-737s, which use the Usher 9950 tweeter and a pair of 8945ks in a 2.5-way configuration.

Now I'm wondering if I should build the Proac 2.5 clones, the Eros, or something entirely different. All I know is that for this project, I want to stick with a proven design. I'm going to fool with much less expensive drivers to learn how to build crossovers.

In the meantime, I want a great sounding pair of speakers to listen to. I want something with some life and some vibrance. I listened to the Sonus Faber Concertos and they were lifeless and dull to my ears. I listened to a 2.5 way Scan Speak system with the 8535s and one of the 2905 tweeters, and liked that sound, which is why I think the Ushers may fit the bill, although it seems like the Proacs would too.

I figure if I really don't like the sound, I can buy 2 more tweeters and build a pair of Dennis Murphy's Usher 2-ways.
Anybody have any advice or suggestions?

[J2JD]

Hi, Are you planning to copy the Usher CP-737 with the exact same cabinet dimensions and the slanted baffle? Also do you have the Usher designed xover? If not, Id go with the Eros because it is a well proven design. Its a great speaker. Also, the Usher 8945 woofer is a drop in replacement for the Vifa PL18. HTH-Brian

[coolkhoa]

SEAS Thors/Froys?

[Jim85IROC]

I have the CP-737 crossover from an article that D'appolito wrote about designing it. I also have a zalytron crossover that D'Appolito designed for them using the same drivers. Regardless of which crossover I choose, I'll experiment before-hand with tilting the tweeter and I'll also try it vertical to see how much of a difference it makes. Tilting the tweeter will probably cause a slight rolloff at the higher frequencies, but at the amount it's tilted on the 737s, it's unlikely to be all that audible. I've been comparing the crossover of the 737 to Dennis Murphy's 2-way, and they are remarkably similar. I didn't plug the numbers into the calculator yet, but it appears that the main differences are due to the amount of tweeter attenuation needed. Both use approximately the same crossover frequency and exactly the same topology.

I remember reading on Wayne J's site about the Usher being a drop-in replacement for the PL18, but I talked to Dennis Murphy, who has used both drivers, and he disagreed with Wayne's opinion. He was quite clear in his opinion that the drivers don't measure similarly enough to consider the usher a drop-in replacement.

I looked at the thor, but it's a good distance out of my budget. Madisound gets a grand for the parts, which is almost double my budget.

[J2JD]

I happen to have this available, it was saved from Waynes site; Name: Wayne
Date Posted: Dec 18, 03 - 1:11 PM
Message: With the Eros MK1 crossover, you can pretty much just drop the 7" woofer drivers in as a replacement for the Vifa PL18's. You will want to tune the enclosure to a slightly lower frequency, however (I'd go down to about 35 hz). ////////
Im aware of Dennis reputation but Im not sure if Dennis would know unless he studied Waynes xover. Afterall Wayne did design it and he had the 8945 on hand to test. Also Wayne does mention to adjust the tuning. Its not really a big deal tho, its a great speaker as designed. The PL18 is a fine driver. Re the Zaly xover; I find they always need more tweaking...always!

[Jim85IROC]

I'm no crossover expert, but the zalytron crossover appears to clearly be inferior to the one in the CP-737. I would seriously guess that D'Appolito would use his best crossover in the Usher design, not the Zalytron.

The crossovers are identical in topology, except that the zalytron version doesn't have a zobel on the woofer circuit. Subsequently, the crossover values are adjusted. Overall, this isn't going to produce as smooth of a rolloff. The Zalytron also uses a bigger inductor on the .5 woofer,