Looking for advice on "sweet" tweeter?

[Leonidas]

First I would like to thank all you members for giving me a lot of information and inspiration in the last three years.
About two years ago I started listening again for a new set of speakers. Aiming for a modular d'Appolito 3-way system.
First I build a Tony Gee - like construction with 2 Vifa 17 WP and an XT300 , first order series x-over. Took me about half a year to get the right sound (to my ears).
Then I start listening to woofers at several places and ending up with Vifa 10 inch woofers with a composite , paper/carbon, cone
They sounded the way I wanted it.
Unfortunatly I tried everything with the x-over again and again to make it sound right , to my ears, but didn't succeed.
(I didn't want to go to higher order x-overs.)
Until I changed the XT for an old Dynaudio D28AF , which improved the sound alot.
My question is : Is there a tweeter around (reasonable price!!)
That will work better then the D28?
My x-over is at 2500Hz, 6dB series. But I would love to go to 2000Hz at .
Any suggestions???

[Leonidas]

Picture of the modular setup at this moment.
Perhaps my previeous message wasn't to clear.
I like the D28 much more then the TX300.
Perhaps what some might call "synergy"of the system ??
The dynaudio sounds less sybilant , to my ears , which I find more "sweet".

[Leonidas]

The proteus-like centre of my system.
For the moment 2x Vifa 17 WP and Dynaudio D28 AF.

[Calvin]

Hi Leonidas,

have used the D28 (without ferrofluid) and the XT25. The former with 2 15cm-Drivers in a symmetric D´Appolito-Style. I found the D28 too mellow for my taste with too less resolution. Using the D28 without the Ferrolfluid improved things much. Still the D28 sounds very smooth.
A newer Design (the Calvini) features two 17WN225 by Vifa (imo not only the oldest but still the best 17cm-Driver of Vifa ) and the XT25 is mounted in a spherical Horn. The XT sounds silky smooth this way without giving in on resolution and with the chosen dimensions of the Horn step response is excellent.
Compared to this, the D28 w.o FFL and even more the FFL-filled D28 sound dull and mellow.
A minor drawback for some applications is the high directivity of this sytem

[Leonidas]

Hello Calvin,

Thanx for the quick reply.
Your idea about a wave-guide / horn for the XT looks promissing.
What order x-over an freq. do you use?
Your vifa's look the same as mine , will do some research on your type's.

[Calvin]

Hi,

with the horn the frequency esponse of the XT25 (its identical to the XT300 apart from metal face plate) alters. It becomes a rising response with a max of app.100dB at 2kHz and from then on a steady linear falling response. So You can design the HP-filter with a higher cutoff-freq to get a linear response again. I used a second-order HP together with a Notch on the Tweeters fs. The Filter runs without any serial resistors to fudge with sensitivity at a crossover point of app. 3kHz. The box has a sensitivity of 93dB, which is just a bit over the tweeters sensitivity (thats what made me think about a horn in first place!). So the overall frequency response of the box is very linear up to app 15kHz and starts to roll off above this point. Using the horn had several benefits. Distortion at the lower frequency range is reduced, the tweeter has ample headroom left, the rolloff at the upper end leads to a very crisp, but smooth top end and step response and phase responses of the woofers and the tweeter is improved (the horn is 38mm deep)
Some listeners at the High-End-Fair stated, they hadn´t heard the XT before so smooth on one hand, so dynamic on the other.

The Mid-woofers I use are paper types with a small VC of 25mm diam. Because of the smal dustcap and just the 17cm basket they lok a bit oldfashioned. They are rather the brain- than the muscletype They have the highest SPL of the Vifa-range a strong motor, yet a leightweight swinging system. Measurements show very easy to use parameters for a BR-loaded small box. frequency response is very smooth with a close to perfect roll-off -You might be tempted to run this speaker even without any Filter if it wasn´t for beginning directivity. In the Calvini I use just a serial inductance of 0.56mH

jauu
Calvin

[Leonidas]

Did some research on the differences of the speakers.
Seems my 17 WP's are of 3 dB less sensitivity then yours, so I have to pad down the XT300.
Further I checked my system and it seems impossible for me to reach the inside, so I have to build new prototypes.
Would you be kind and take a look at ZAPH AUDIO , for the waveguide he uses.
Do you think it's worth ordering at MCM and using with the XT300??
At least wih your solution I don't have to buy new tweeeters !!
I do agree on the notch, especialy if I will insist on a 6 dB serial x-over.
Thank's again.

Leon

[Calvin]

Hi,

I don´t know this WG, but as the text says: "Waveguide construction is critical."
The WG must be modified anyway to accompany the larger diameter diaphragm of the XTs, so why not have a WG or Horn made for Your purposes? The front plate of the XTs has a small flange like a mini-horn, so my horn features a contour with kind of a ´blade´ that fits perfectly into that flange giving a steady and smooth contour and self-centering. Using something different construction could lead to a ring-style little cavern with effects on the frequency response

jauu
Calvin