advertisement


Pseudo D'appolito configuration by towering two pairs of same speakers?

G

gregvds

pfm Member
Hi,

I fear this can potentially seem powerfully ridiculous, but I have that idea for some time now.

Take two pairs of the same speakers, and put one pair on top of the other, upside down, to achieve more or less a D'Appolito configuration. Now how to wire this, serie or parallel (halving or twicing the impedance?).

Go on, shoot!

:)
 
I have B&W DM220 with DM330 upside down on top of them. Wired in parallel for a nominal 4 ohm load, I haven't tried series 16 ohm but might get around to it one day.
 
Ok, I'm not alone with this idea :).

Did you find an improvement in imaging and stability of the stereo scene, as d'Appolito speakers do usually offer even if speakers are not strictly identical?
 
The problem is having two tweeters, as the sound will not combine well at the higher frequencies. That's why this type of speaker is usually dual woofer, sometimes dual mid-range but never dual tweeter. The treble would become limited to a very narrow spot in the vertical domain.
 
Tenson said:
The problem is having two tweeters, as the sound will not combine well at the higher frequencies. That's why this type of speaker is usually dual woofer, sometimes dual mid-range but never dual tweeter. The treble would become limited to a very narrow spot in the vertical domain.
Click to expand...

There would probably be some nasty HF comb filtering between the two domes.
 
Mile Nestorovic (Nestorovic Labs) used the idea of having per channel two satellites one on top of the other for his System 16

satela.jpg


He though made the upper one specifically for this purpose. The all four speakers are matched (that was the most extensive part of building the whole loudspeaker system). With ten years of experimenting I found out that the best gain of quality of sound was to decouple the two speakers from another. I tried so many materials, lot of them sent from friends, and at the end I'm using the Nimbus from Harmonic Resolution System. The problem of them is that they are 2-3 mm higher than what it should be but the sound is definitively clearer. At 2.60 m distance (sweetspot) there were hardly any difference in the response frequency. Also be aware when you put two speakers on top of each other to adapt the hight of the lower one. ;)

lspges.jpg
 
gregvds said:
Ok, I'm not alone with this idea :).

Did you find an improvement in imaging and stability of the stereo scene, as d'Appolito speakers do usually offer even if speakers are not strictly identical?
Click to expand...

Bass response extended effortlessly to below 20 Hz... (something to do with effective bass "driver" of almost four feet diameter, I think), very nearly point sources (tweeters are near the "top" of their respective cabs, they used to diffract sound around the corner and bounce treble upwards, now directed forwards), no ill effects from lobing or other causes because the mid-point between the tweeters is just about perfect ear level in my room at my favoured listening position, slight lift in image height because the 330 is 1dB more sensitive. Win, win, win. :)

The downside: loudspeaker towers that are about a foot square and more than six feet tall as well as being heavy... a bit awkward to move around if you need to.
 
Thanks for all the answers so far.

I didn't think about the comb HF potential problem. So I won't buy a second pair of RS5 to put on top of mine. Maybe I'll try it for fun with the RS1 of the second system when acquired :).
 
Remember people used to stack Quad 57 panels vertically for more volume/bass, that must have had some strange measurements
 
Yes, but also remember that the construction of the drivers in the 57's meant that they had quite different dispersion to that of a dome tweeter.
 
IIRC much of the logic in stacking Quads was to increase the treble dispersion and therefore the listening area. Often a Decca London ribbon horn tweeter was placed between the two Quads, again to help in this regard.
 
YNWOAN said:
Yes, but also remember that the construction of the drivers in the 57's meant that they had quite different dispersion to that of a dome tweeter.
Click to expand...

Yes, its a line source.
Stacking them just lengthens the vertical line so that they sound good sitting or standing.

Does nothing for lateral dispersion though.
 
So, as two tweeters can potentially be source of trouble, my mind was wandering, and I imagined a brand that would develop a range of separated units speakers, that could be combined to create a two way, a three way, D'appolito configurations, two and three ways, even adding later BMR unit and so on, so one could begin low with a HF + MF config, add then a second MF, or a LF to go D'Appolito or 3way, completing later for a D'Appolito with one LF below, then a second one on top, then why not adding two MF, and so on.

Do you know of some brand that did this already? I know some did develop speakers with all transducers in their own sealed and decoupled cabinet, but they were not intended to be modular or did they?

That would be rather cool, kind of evolution path with one brand of speakers.
 
A few of Usher's speakers are in a D'appolito configuration (infact, designed by the guy himself). Unfortunately they don't offer custom configurations, but I can see why you'd go to the efforts for such configurations. I have a pair of Usher Mini Dancer 2's in this setup, very worthwhile indeed.
 
Robert said:
Yes, its a line source.
Stacking them just lengthens the vertical line so that they sound good sitting or standing.

Does nothing for lateral dispersion though.
Click to expand...

Yes, I know - as you say, stacking them does nothing for lateral dispersion - neither improves nor worsens it - the same cannot be said for multiple dome tweeters.
 
Tony L said:
IIRC much of the logic in stacking Quads was to increase the treble dispersion and therefore the listening area. Often a Decca London ribbon horn tweeter was placed between the two Quads, again to help in this regard.
Click to expand...

Hmm...as far as I was aware, the logic of stacking quads was to increase panel area and stacking them achieved this without compromising dispersion (it doesn't improve it either though). The Decca ribbon is just to extend the frequency range, I believe.
 
YNWOAN said:
Hmm...as far as I was aware, the logic of stacking quads was to increase panel area and stacking them achieved this without compromising dispersion (it doesn't improve it either though).
Click to expand...

It can improve vertical dispersion as one tends to align the two Quads to cover a slightly wider area - the usual way was to stack them bottom to bottom making a 'curved' speaker, i.e. top one firing up a little, bottom one down a little, thus less beaming.
 
You must log in or register to reply here.


advertisement


Back
Top