SCAN-SPEAK R2904/700000 vs. D2905/990000 tweeters

[Sony]

Which one is more adequate to 2 and 3 ways designs?

What is the sonic character of each?

Thanks!

[5th element]

I cannot comment on the 70 series because I have not used them. The 97 and the 99 are the same tweeter but with different faceplates. The 97 is a very nice sounding tweeter, smooth, dynamic with great resolution. Recommended where ever you want to use a tweeter and have some money to spend.

But from the specifications the 93/95/97/99 range all have 0.4 mm of xmax. The 70/71 range only have half this at 0.2mm.

I dont know how the new tweets sound but they should be rather good, I would expect better then the old range. If that were the case then id use the 70/71 in a situation where the crossover is away from then 2khz mark and closer to 3.

The 93+ range can handle low xovers easily because they have low resonance and high excursion. But because the newer tweets have less xmax available they wont be able to cross as low.

Therefore Id recommend the older models to 2 ways which may require a lower xover point. Then the newer tweets for 3 ways where a 5" or smaller mid can be selected for a higher xover point.

Ofcourse if you are using a woofer in the two way which can cross over higher then use the newer models.

[wigginjs]

I was looking at the specs for a Seas tweeter (27TDFC) and I noticed they don't list an xmax parameter, but they do list "linear coil travel (p-p)". Are these synonomous? If so, the 27TDFC has a 0.5mm xmax, this would suggested that it could be crossed relatively low does it not?

[bbksv]

Xmax is only half of that....it is only one way travel

[wigginjs]

In what way does xmax relate to crossover point? Whats the lowest reasonable frequency for a tweeter with a 2.5mm xmax?

[joe carrow]

Originally posted by m0tion
In what way does xmax relate to crossover point? Whats the lowest reasonable frequency for a tweeter with a 2.5mm xmax?

Assuming a tweeter has 2.5 mm of xmax, and it's linear- the lowest crossover is a function of the tweeter's radiating area and desired SPL.

Here's a link- http://www.linkwitzlab.com/thor-design.htm

there is an excel spreadsheet there for calculating max SPL for a given excursion and Sd.

Incidentally- what type of tweeter is that? 2.5mm seems like a lot, and to get that sort of excursion in tweeter territory would take a lot of power.

Joe

[foo]

I think 1 of the main advantage of 700k is it's efficiency .
It's 94db/2.83v efficiency is very helpful when u wanna
use a MTM setup with 88db+/2.83v woofers.
At the meanwhile , u can also consider 710k tweeter which has
the same efficiency as 700k ,but a soft dome might create softer sound that can fit into most systems easily.

[Pan]

Accuton C23 has some serious travel, xmax 1.2mm (2.4 mm p-p overhung).

/Peter

[kelticwizard]

Have not hear either tweeter.

YOu can see the frequency responses, and the pictures of the tweeters themselves, at:
www.peerless.dk Click "Enter a world of speakers"

I can mkde a few observations though.

First, the 2904 is 4 ohms, the 2905 is 6 ohms. The 2905 would therefore be amenable to working with 8 ohm drivers, though the 2904 can be made to work with them too.

The design of the 2904 looks radical, the phase plug on top makes it look like some kid glued a miniature chess pawn onto the tweeter dome when his parents weren't looking.

More seriously, the high frequency dispersion of the 2905 is MUCH superior. With the 2905, the 30° off axis measurement stays within 3 dB up to 15, 000 Hz before diverging quickly from the on axis measurement. With the 2904, the 30º measurement is already 8 dB down from the on-axis measurement, and sinking fast.

Since one of the important criteria for a tweeter is good dispersion, I would definitely be inclined toward the 2905.

[kelticwizard]

Compare for yourself. Here is the 2905/9900000. 30° off axis response stays within 3 dB of the on-axis response all the way up to 15,000, before going down quickly.