I'd suggest browsing Dave Pellegrene's Picasa album. Lots of waveguides, tweeters and measurements...
Pellegrene Picasa
But I'm not sure it will answer the second part of your question...
Pellegrene Picasa
But I'm not sure it will answer the second part of your question...
Morel CAT 378 1-1/8" Soft Dome Horn Tweeter
Thats one I'd like to try - perhaps with a larger woof in a 2 way.
Thats one I'd like to try - perhaps with a larger woof in a 2 way.
Right, Dave has had lots of experience making them. However, if a layperson such as myself tries to get some made from scratch, which tweeters would be most likely to give me great results with a minimum of tinkering and tweaking?
The dome tweeters used in the EV100S work well with waveguides, as they were designed for that use. They can go quite loud without sounding harsh, have used them with 10", currently have one in a 2x5". I think I have one more laying around dead, just found out diaphragms are readily available, though I don't know if the driver itself is still available new. I purchased them from EV as replacement parts with crossovers back in the early 1990s.
I made round 90 degree waveguides for them by laminating pieces of plywood cut with a 45 degree router bit using a circle jig. The mouth of the waveguide was the baffle, depth was 2.5" ( four pieces of 5/8" IIRC) crossover around 3500 Hz.
They do have some "squiggles" in the response around 10 or 12kHz, possibly due to diaphragm breakup, but may be diameter related.
I'd suggest the XT25TG30. It's the most forgiving I've worked with as far as guide shape and throat intregation.
Dave
I fabricate my guides to fit over the surround which allows me to reduce the throat to the size of the diaphram. If done right this will eliminate the usual dip around 9-12 kHz. If you are not doing this and want to fit the guide around the surround the N26C works well in a 7x5 elliptical guide. Somewhat costly but an excellent sounding tweeter.
Dave
If the throat goes on top of the surround, inside of around it, isn't there a risk of contact between the surround and the throat during high outward (away from motor) excursion? Is this something you have engineered out of the waveguide somehow, or is it a non-issue because nothing happens when the surround touches the throat?
It is important for the guide not to hit the surround. Most tweeter surrounds do not move that much. Although it depends a lot on the tweeter. For instance the RS28 is a tough one to work with because the surround is somewhat large and it plays so low. The Audax TW25 has a very small surround so it is much easier to get in close. Each tweeter I work with is a little different and takes a little different shape to fit the surround. Sometimes a slight angle change at the throat can make a positive change in the response say on axis but I have to check off axis because it might make a negative change.
At the moment my favorite tweeter has been the D2604. It works in the same guide baseplate as the XT25 and several other of the SS line. For a $50 tweeter it sure does sound good and measure well in my guides.
Here is a link to some measurements with a few different guides I've been working on.
https://picasaweb.google.com/101632266659473725850/ScanSpeakD2604833000
Dave
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