Keith's Acapella system

#1
Since i'm new here I thought I would post a description of my system. Some of you would know me from other forums and would be familiar with my journey. It has been a rather unique one, and more or less centers around my struggle to get my speakers to work properly.

The Acapella Violon has a plasma tweeter, a horn midrange, and a conventional bass cabinet. When I bought these speakers in 2007, I was aware that the bass was its downfall. It was muddy, indistinct, and noticably slower than the midrange and treble. However, the midrange and treble was unlike anything else I have ever heard - crystal clear, dynamic, and utterly revealing.

At the time, I thought I could cure the bass with a few simple tweaks (e.g. bi-amp, subwoofer, etc) but little did I know! Making this speaker sing has taught me a LOT about audio. Along the way, I obtained a measurement setup, dissected the speakers, tried to understand loudspeaker engineering, bought a subwoofer, bought a crossover, performed some surgery to bypass the internal crossover, learnt how to program a DEQX, and finally got a custom driver manufactured to my specifications. My speaker is completely unique - the drivers I had manufactured are a special one-off, and there are no speakers anywhere else in the world in existence that use the same driver. Many thanks to a local speaker engineering firm (SGR) for many hours in consultation and help.

This is the equipment list:

Source
- Playback Designs MPS-5
- Micro-Seiki BL-99V turntable, MA-505 Mk.2 arm, Lyra Dorian cartridge, RCM phono stage

Amplification
- Cary SLP-05 preamp
- Marchand XM-44 crossover
- DEQX HDP-3 crossover
- Cary CAD-211AE power amp
- SGR EL30S power amp

Speakers
- Acapella High Violon 2001
- JL Audio F110 subwoofers x2

Cabling
- Acrolink 6N and 7N
- Transparent

Here are the pictures:




The vertical panel of lights next to the subwoofer is the DEQX HDP-3. Its sole purpose is to perform subwoofer corrections, however I may have other plans for it.




Equipment stack. SGR rack.


CD collection in 2010


CD collection in 2012. On the top left of the CD rack is my remote receiver. It receives RF from the transmitter (Marantz RC9500) and controls the whole system via macros.

Finally, here is a video of my system:

 
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#2
Here are some images of the loudspeaker dissection.


Anatomy of a plasma tweeter. Remove the top plate, and this is what you will see. On the right is the power supply. On the left is the high pass filter, volume control, Class A amp, and various other electronics.


Remove the center panel and you see the PL519 valve, the high tension coil, and the combustion chamber - milled from solid brass.


Another view.


The anatomy of the bass cabinet. This is a very unusual combination and explains why the bass sounds so muddy. An internal 8" driver is mounted in that round hole, and runs direct from the speaker binding post bypassing the low pass filter. This fires into the back of another driver which is externally mounted - this driver is connected to the low pass filter.


This is a driver comparison. On the left is the standard driver that came with the speaker - it is a SEAS CA125, which you can probably buy as a spare part for $80. Note the flimsy looking stamped metal basket. On the right is the custom driver, manufactured by Loranz Audio (Melbourne). Note the cast iron basket, the more substantial magnet assembly, and the "nice" binding posts.


This is the midrange horn. The entire enclosure weighs a bloody ton. After a lot of swearing, we managed to get the horn off and we found out why - the entire enclosure was filled with sand!


This is a picture of the enclosure. As my friend said, it is very German. Only a German would construct an enclosure out of thick ply, fill it with sand, and then think to himself ... let's line it with lead!


After removing the sand, you can view the crossover for the midrange horn.


This is how you get the sand back into the enclosure. There is a little fill hole at the back.
 
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RogerD

Active Member
May 23, 2010
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BiggestLittleCity
#4
Very nice!
 

Peter Breuninger

[Industry Expert] Member Sponsor
Jul 20, 2010
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#6
Keith, can you shoot video? PM me. Your system belongs with the "worlds greats" on avshowrooms. I can't wait to get Steve's system video'd!!! Any member who wishes to share their set-up in video please PM me.
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
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#8
Very nice! I would redo he crossover... electrolyics?
 

FrantzM

Member Sponsor & WBF Founding Member
Apr 20, 2010
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#9
Keith

I am also a fan of Acapella .. I got the shock of my life when I heard an Acapella Sphaedron, I though that for the price it ought to be good then I heard a Campanille driven by Burmester electronics ... The best horns I have heard to date and likely the best tweeter out there ... The Sphaedron was not lacking in bass, nor did the the Campanille albeit to lesser extent and quality ...

I am curious why the Marchand and the DeQX?

BTW Tour system and lts layout are HIMPPRESSIVE .. not a typo .. Hyper-IMPRESSIVE ! :)
 
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fas42

Addicted To Best
Jan 8, 2011
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NSW Australia
#10
I can only echo the sentiments of everyone else here: a very impressive journey, that dedication to the "cause" is what this hobby is all about! Personally, I would not touch that crossover; to me it looks as if it is already highly optimised, the electrolytics are heavily bypassed, which is the key to making the end result capacitor work as it needs to.

What I don't like is that you attach to the crossover with push on connectors! All that hard work, potentially weakened by a "junk" connection. Soldering is inconvenient, yes, but it may make a major difference ...

Cheers,
Frank
 

Ronm1

Member Sponsor
Feb 21, 2011
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wtOMitMutb NH
#11
Impressive and its an understatement. I'd love to invite myself over for a few hrs with some of my disc's.
 
#13
Keith, can you shoot video? PM me. Your system belongs with the "worlds greats" on avshowrooms. I can't wait to get Steve's system video'd!!! Any member who wishes to share their set-up in video please PM me.
Hi Peter, I had a quick look on your website. Yes I can shoot video but I am camera shy :) As long as I remain on the other end of the video there would be no problem.
 
#14
Very nice! I would redo he crossover... electrolyics?
The crossover that you see is the internal crossover for the midrange horn. I am thinking of bypassing it altogether. Right now I am still weighing up my options and deciding whether or not to do it. It is no simple matter, it takes several hours to get at the crossover, having to solder and desolder at an awkward angle, and then even more messing around with the external crossover to get it right.
 
#15
I am curious why the Marchand and the DeQX?
Thanks Frantz. As I said in another thread:

"In my system, I have the ability to compare my DEQX against a straight wire. If the DEQX is really transparent, then doing an ABX, level matched, against straight wire would be a fair test? I have done this comparison and repeated the experiment for several visitors and they all heard the same thing. The DEQX was simply set up as an ADC-DAC and performed no processing on the sound. It would simply take the signal, convert it to digital, then convert it to analog. The ONLY processing was to level match the output to the cable. Compared to straight wire, the DEQX destroys the sound.

The purpose of doing that experiment was to do a cost-benefit analysis. What was the cost of the ADC versus the benefit of all that digital correction? This is the answer:

The cost comes from the ADC. If you feed the DEQX a digital signal, your cost would be far lower. Using the ADC destroys resolution and dynamics. Regardless of how it measures or what specs it claims, there is no arguing with the audible result - everyone could pick it and describe exactly the same thing.

The benefits are well documented - speaker and room correction, and a level of integration that is simply not possible with any other technology. The DEQX is a very purist solution for those of a particular philosophy - namely those who only listen to 16 bit audio, have no analog sources, and feed the DEQX digitally.

Obviously, the cost-benefit analysis will be different for different people, different systems, and different philosophies - which is why I am not exactly bucketing the DEQX. It is a very good unit, but for my system - it doesn't work."
 

ack

VIP/Donor & WBF Founding Member
May 6, 2010
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Boston, MA
#16
The crossover that you see is the internal crossover for the midrange horn. I am thinking of bypassing it altogether. Right now I am still weighing up my options and deciding whether or not to do it. It is no simple matter, it takes several hours to get at the crossover, having to solder and desolder at an awkward angle, and then even more messing around with the external crossover to get it right.
I understand... when I redid mine, I spent a total of about 40 hours per speaker, and it was easily accessible. If you remove it, make sure you understand what it does and why it does it, first... And you can probably do a lot better than those NTE resistors.
 
Jan 23, 2011
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Amsterdam holland
#18
Nice system /pics keith , i ve never seen someone take it all apart though:D :
I read you find the bass muddy.
Which units take exactly which frequencies its not completely clear to me
You have a
plasmatw
horn
double woofer system
sub

I assume the plasma tw and horn have a duo/combined crossover with 1 plus /min connection as on the scheme > 600 hz but you might want to drive them seperately i understand
Or do they have there own separate filter , like the pics ?
If you bypass the filters completely wouldnt that give efficiency misalignments (bypassing resistors)or can one adjust individual output via the" equalizer"
 
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Jun 6, 2012
92
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Melbourne, Australia.
#20
I can assure you all that it sounds as good as it looks which is more than he said about my system. ;)
 
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