Dayton RS28F.. good enough to match Scan Rev's?

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The larger, dual magnet variant, the XT25BG has a lower resonance and therefore lower crossover point.

The resonance on the XT25 has little to do with its usable range, its problem lies in its harmonic products profile. 2nd harmonic is very high under 2Khz, 3rd order distortion also rises rapidly under 1.5Khz. The very short waveguide ends with a sharp edge, screws are not sunk enough in the holes provided, the holes themselves are too large and too many, and the plastic faceplate bends easily if you tighten too much. Many of these tweeters have excessive glue on the inside which affects their performance. It also lacks the very high 15Khz+ range (and does need a super tweeter in my opinion) and can sound like an angry mantis if used improperly. That all being said, it is a fantastic tweeter if used correctly but many designers don`t. Its cheap as a standalone unit which attracts lots of DIY-ers and companies, but the crossover it usually requires (without a waveguide) increases its overall cost by almost 25% if you go on cheap parts.
 
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I'm really not sure if Mario has ever measured or heard these tweeters in real life. I do like using felt around tweeters, it can solve a lot of these problems. Madisound sells pre-cut felt rings if you'd like, or use a rectancular section of PSA felt to cover most of the baffle and use a 2" craft hole punch to make the center hole.

And lacks above 15kHz? Needs a super tweeter? Huh? Only if you mean off-axis. These tweeters are a little narrow, but look at how many manufacturers choose to put them in a wave guide and you'll see controlled dispersion is not always a negative thing.

On-axis, none of my 3 samples are anything but flat. The complaints of misuse are usually from designers expecting it to roll off when it does not exactly because it has no drop off. It's flat well past 20kHz, so designers who usually get lesser tweeters are "helped" by their natural drop off which the XT25 does not have.

In addition to measuring them, I listen to it side by side with my Mundorf AMT's and think they are a fabulous bargain.

Best,


E
 
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I'm really not sure if Mario has ever measured or heard these tweeters in real life.

Tell me what you want me to add to the photo to prove its not found on the internet and I will post you a pic of at least one pair which I have right now. Its, Erik, on speakers I built with this tweeter many years ago. About 7 years ago.

The complaints of misuse are usually from designers expecting it to roll off when it does not exactly because it has no drop off. It's flat well past 20kHz, so designers who usually get lesser tweeters are "helped" by their natural drop off which the XT25 does not have.

That statement is by all means hillarious.
 
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You can add the pics here. Just use the "Go Advanced" button and then the Add Attachments, finally, use the link from the attachments in the pic icon.

I have measured them too, added them to another thread. If you are measuring drop off on the XT25BG, bad tweeters or bad mic.

As I also state, in comparison to very high end AMT's they sound great.

Best,

E
 
Bill,

Do you already have the Scan Speak woofers? If you are still mulling on the drivers, here's a design that you might like:

MW19P-8

Some savings on the woofer, but the tweeters are much higher cost....

Edit: Cross-over parts are also petty steep (ouch)...
 
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1. If you guys had to choose between the sb26 stac vs the rs28f for a xo frequency around 1400-1500 which one will you go with?

2. Would it be advisable to use a waveguide with these tweeters ? And would low freq output be increased in a waveguide? I am looking at the EOS6 waveguide. Any other recommendations?

3.From research I have seen that the sb26 has an efficiency of 91 and has great off-axis response and the rs28f has an efficiency of 87 but goes lower. When I checked the frequency response graphs I see both have great response on the low end. Which of the two has less harmonic distortion?

I am constructing a TM with the Faital Pro 6FE100 that has an efficiency of 91db.

Edit
Found some answers here:
http://www.diyaudio.com/forums/multi-way/292719-tweeter-100-a-2.html#post4741999
 
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