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amplifying stacked speakers (D'Appolito i.e. tweeter atop tweeter)

Wil

Well-known member
May 8, 2020
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I have stacked Concept 20 loudspeakers at home:
Concept 20 stacked.JPG
Its performance reflects my choice of amplifier. Simply, I've tried 5 distinct amps (as well as in bi-amp, and tri-amp combinations).


Backstory, in 2007, Ken Ishiwata stacked Performance 6 loudspeakers so as demonstrate capability of MA-9 monoblocks:
"Connected in parallel, the speaker arrays presented an impedance of around 3ohms to the [MA-9S2] mono amplifiers, which were thus delivering some 700w into each channel, more than enough to produce a pretty dramatic effect."

This is a graphic I did, summarising the-memories, when I sent news to Ken that I'll-be-stacking-too:
KI D'A.jpg
N.b. Concept 500 is D'Appolito in-one-box.

And Tim de Paravicini also has demonstrated with stacked LS3/5a:
TdP LS3:5a.jpg
LS3:5a TdP.jpg


Remember, if you too want to try stacking speakers, my advice is firstly have a suitably powerful amp, then 2 pairs that are the same model of loudspeakers.

And final remark, sweet-spot for my stacked Concept 20 is ears parallel to tweeters. Okay because it's luckily the height of my seated position. Treble clarity diminishes if I stand up (which I sometimes especially do for those recordings where…
 
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DougK

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"And final remark, sweet-spot for my stacked Concept 20 is ears parallel to tweeters"

You have 4 tweeters, which pair is parallel to your ears, upper or lower??
 

Wil

Well-known member
May 8, 2020
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Take a closer study of the photos, and consider too bracketed ending of the Thread title.

"And final remark, sweet-spot for my stacked Concept 20 is ears parallel to tweeters"

You have 4 tweeters, which pair is parallel to your ears, upper or lower??
Indeed, general rule for the speaker model undergoing D'Appolito stacking is that its tweeter be near the top surface—so as to reduce distance between…


So it's clear, rather than writing exhaustively, I've always deliberately left room for answering of anticipated questions.

Another time I give details on advantages and drawback of rotating back to PM-KI Ruby F.C. Bus…
 
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Wil

Well-known member
May 8, 2020
177
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We needn't argue whether stacking speakers is for-the-cognoscenti.

Because I had been questioned elsewhere about it, I'm merely providing its own Thread where stacking can be discussed.


What I trusted the reader to perceive from my 1st Post was that if there's a preference for using small speakers—similar to the (well regarded) LS3/5a—its performance may be improved by D'Appolito stacking.

So, another small example is Ken Kessler's reporting from earlier this year:
TA.JPG


In case you didn't link through, for stacking the (taller) Performance 6, "problem, Ishiwata explained, wasn't suspending the inverted speaker - the existing screwthreads provided for floorspikes proved up to the job, which is some tribute to the strength of the composite cabinet - but getting the precise three degree tilt from the vertical required for correct alignment of the speakers."
Stacked Speakers KI.jpg


Reminder, having a capable amplifier is a must—you're halving speaker impedance when…
 
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