18sound NSD1095N v's B&C DE250

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D

D OB G

Member
Joined 2007
#1
I'm using a B&C DE250 in an 18sound XT1086.

Very smooth. Great dynamics. But I'm missing some very small signal detail that I'm used to on my Esotars.

I've tried the waveguide (horn?) with and without the open-cell foam. Better without the foam IMO in every way. (equalized in both configurations- flat to 17 kHz).

Has anyone tried the top of the line 18sound driver?

I can eq with DEQX.

So I'm looking for the smoothness of the B&C, but with much more detail (shimmer on cymbals, triangles e.t.c., rosin on bow/strings).

I'm not into HT. Stereo, music, only- not at ultra loud levels.

David
 
#8
Mr Ebaen at 6moon said the very same thing about a ribbon vs his Esotar
Maybe the Esotar really is a remarkable tweeter, and as good as its reputation
I have a project coming, so I am very concerned about this issue, which seems to be valid

Another member and gorn enthusiast has previously claimed that a setup with CD/waveguide lke yours really needs additional supertweeter, like one of the Fostexes, despite the difficulties
Though other members has claimed the opposite
 
#9
Thanks tinitus,

So perhaps DE250 plus supertweeter, or something better than the DE250 (the obvious preference).

Incidentally, 18sound show graphs of CD only to 12500 Hz. Is the XT1086 causing the loss of detail, even though the graphs look impeccable up to that point? What happens above that (even though they claim response to 18 kHz)?
 
#10
Man, you are an "aussie", so why dont you get yourself a nice pair of Azura horns, I dont think it gets better than that...mind you, I am a complete newbie on these matters

But I know a bit about crossovers, and proper xo function can be significant...are you sure your xo works properly, those CDs are tricky to get right
 
#11
In this instance I'm using a DEQX HDP3.

The mid is an 8" PHY.

I've tried every crossover between the horn's CD limit of 1200 Hz, and 8 kHz.

So, a perfectly flat on-listening axis response.

1200 Hz at 60 dB per octave sounds the best

(It can't be the DEQX's fault, because the music is there with the Esotar).

Maybe I should check out the Azura horn!

But what I really want to know is, is there a better compression driver out there i.e. 18sounds' nitride coated titanium?
 
#12
I just tried paralleling an esotar with 3 uF, to the DE250, and then producing a linear response with the DEQX. (i.e. the esotar is producing quite a bit less than 50% of the sound, at least to 17 kHz).

For a start, this produces a flat output to 25 kHz. (As opposed to 17 kHz- does this matter??).

I was testing this, with my wife, listening to Debussy harp and oboe, and lo and behold, we could both hear more detail with the esotar in circuit (and this without it even being time aligned).

This fussing around is fun and all, but I still want a better compression driver.
 
#13
D OB G said:


The mid is an 8" PHY.

I've tried every crossover between the horn's CD limit of 1200 Hz, and 8 kHz.
Click to expand...


The use of PHY as a mid is very interesting...have considered it, but I suppose it only works in OB

Crossing a CD is not just about xo-point, but demands special care...traditional xo design doesnt work, but if you cross active I have no idea

http://www.pispeakers.com/Speaker_Crossover_Lab.doc

somewhere from around side 21 is dedicated to crossing CD/horns

If your horn isnt nice and smooth at transistion from throath to waveguide, you may be able to modify it at this point, with maybe possible major improvements

Question is with the use of a PHY 8", is there really any reason to use CD/horn...I am pretty sure that if I went down that road, then I would surely use a RIBBON, and no horns...offcourse I dont know where best to cross the PHY 8", but with a ribbon it may be around 3khz
 
#14
You mention that the response is flat on axis, so I am assuming you are applying the necessary 6db/oct CD EQ?

Have you tried, measuring say 10º off axis as the reference for EQ'ing you are doing in the DEQX? Meaning, instead of using on axis and doing all the trickery, try the same routine but setup your measuring off axis some and make that flat instead. You've seen the posts about Dr. Geddes' measurements on axis where he has a narrow range right on axis where some hills and valleys happen but slightly off axis there is nothing odd?
 
#16
Yes, the PHY is OB. I want to cross to CD where the 8" is starting to beam at the rate of the CD horn.

I cross the speakers in front of the listening position, so it not the on-axis response that is made totally flat, but the listening axis. (DEQX really takes care of all compensation).

I have put putty at the juction of driver and throat to get it as smooth as I can.

I must admit that I have wondered about the spray adhesive, as thin as it is, is there a disruption to laminar flow?

I am happy with the sound of CD and compression horn overall. The dynamics, lack of compression, the way it loads the room.
I just want a better driver....please.....???

David
 
#18
D OB G said:
If I can hear fine detail on the Esotar and not on the DE 250, which is the more accurate (at least at lowish levels)? i.e. which is really distorting?
Click to expand...
Have you considered that the "detail" is the distortion?

Do you really think a dome tweeter does better than a compression driver in terms of distortion?
 
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