crossing over from tweeter to tweeter, mid-size tower concept

[scape]

If there is a topic about this, please link me! I did a few searches and found very little on the topic of two tweeters, especially one crossing over to another.. perhaps that's because it's a bad idea- idk.

I found a decent tweeter that goes from 1khz to 5khz relatively flat (Scanspeak D2606,) and tapers off rather quickly for off-axis listening (10khz and above)- i find most tweeters do this; however, I found another tweeter that is capable of relatively flat response from 4-5k up to 20k+ for off-axis response (FT96H Fostex.) My question is can they be crossed over without sounding bad, are there major repercussions in doing so? Has this been done before? I've seen a few speaker cabinets which have two tweeters, but little on what is the downsides from such practice.

The whole idea is to increase off-axis response for the high-end frequency response, especially at greater than 15 degrees; I'm aiming for about 45 degrees off-axis response to 20khz..if that's even possible within a budget (under 1k$/pair of somewhat mid-sized towers I was considering to build).

So far my mockup includes:
The two tweeters as a possibility, though I may swap out the scanspeak model for an 8ohm.
As well two woofers: a peerless 835016 10" and scanspeak 15m midrange, both are 4ohm (I'm thinking of crossing them at 200hz and 2khz). I'm shooting for 8ohms and around 90+db efficiency, which is why I paired these speakers up. I'll be designing the crossover with my EE friend who has had some experience in crossovers..and likely some software and research on my part

Maybe this is an ambitious project, but I used to design subwoofers and basic single driver fullrange boxes (rather trivial in comparison to this project I think) to compliment my systems, so I'm not exactly brand new at this.

I'm welcome to any criticism (if this entire tower idea is bad let me know!) and advice as well any better picks for speakers; as well I do plan on crossing this over to a sub on some level. Everyone's welcome to the results of course, perhaps this could end up being a fantastic speaker, who knows

[scape]

edit: the scanspeak is actually model 15m/4624G Discovery

[Inductor]

If you can explain why using the two tweeters vs using one. I mean why going with all the bads.

[scape]

for greater off-axis response, the fostex seems to be better at 20khz and greater than 15 degrees. just a thought if it would even make a difference

[rabbitz]

Don't get hung up on super wide off axis performance as in reality you don't need it and can cause more issues. Check the angles required from your listening position. Best to stick with a TMWW.

The only time I've seen a dual tweeter is when it's done for a special reason to crossover one of the tweeters very low.
SP38/13

[Francec]

Since most instruments don't go above 5kHz, Template:Vocal and instrumental pitch ranges - Wikipedia, the free encyclopedia, I wouldn't be too concerned about roll-off above 10kHz or even from 5kHz.

As a test, use a program such as Audacity to generate 30 seconds of frequncies from around 70Hz to 10kHz, burn them to CD and have a listen. You will surprised how little content there is above 5 to 6 kHz.

Frank