Southern Lights (Acapella Violon)

by amfibius on All Out Assault

Description

This system is a culmination of many years of realizing what I value most in music. With audio, the only way to move forward is to know what you want and then work your way to achieve your goal. With that in mind, every component in this system was chosen to deliver what I value most in music. I strongly believe that the first step in any system is to choose the speaker that delivers what you want, and then choose all upstream electronics to make the speaker work.

The Acapella Violon delivers what I want. The plasma tweeter is simply without equal. It works by ionizing air from a high voltage electrode so that the air is sufficiently energized to erupt into a ball of glowing plasma. The size of the plasma flame is modulated to produce sound. No moving mass, no inertia, no coloration from cone material. This tweeter sounds like nothing. There is no metallic ring like you would get from a metal dome tweeter, and no softness associated with textile tweeters. Sound simply emerges fully formed, the speed and dynamics is unmatched. It just sounds real. This is without doubt the best tweeter technology in the world.

The midrange horn very nearly keeps up with the tweeter. It covers a large range from 500Hz-5kHz with shallow (-6dB/oct) slopes either end. The dynamics from the horn match the tweeter, and it excels in delivering instrumental timbre and loads of inner detail.

The weakness in the system is obviously the woofer. The overall quoted sensitivity is 91dB/W/m, and I am certain that the horn and tweeter were padded back to match the woofer. The drivers are 10", and arranged in a pseudo-isobaric configuration. Strangely, the external woofer is run from the crossover (500Hz, -6dB/oct), but the internal woofer is run directly from the speaker binding posts - i.e. full range. The bass is muddy, sluggish, and there isn't much of it. It obviously sounds disconnected from the horn and tweeter.

Furthermore, the speaker exhibits a wicked impedance curve with 600 Ohms for the tweeter, 8 Ohms for the midrange, and down to 2 Ohms for the woofers. This further exacerbates bass problems when run with valve amps.

I was obviously aware of these problems when I bought the speaker, so why did I choose such an obviously compromised speaker? The answer is - I strongly believe that midrange and treble should be gotten right first. If your midrange and treble are not right, you will spend endless sleepless nights trying to fix a problem which may not be fixable. Bass, in contrast, is relatively easy to fix.

I am about to embark on an adventure to fix the bass on my speaker. The first step is to purchase a solid state amplifier to bi-amp. The next step is to purchase a DEQX to control the phase response and group delay of the individual drivers. After this, I will remove the crossover in the bass unit (converting the speaker to active), and change the woofer to a more suitable driver. Finally, I will build a custom crossover to go before the midrange/tweeter, which will prevent the ADC/DAC stage of the DEQX from contaminating the all-important midrange and treble.

Last but not least, I will return to an analogue source, but such a purchase is still very much on the horizon.

Watch this space.

Previous entry ---

Thanks to AudioGon, I became aware of this speaker. After salivating at some of the nicer Acapella setups here I had to go have a listen. Boy, was I captivated. The most revealing speaker I have ever heard. The plasma tweeter is something else!

I am currently also upgrading from the Cary CAD-805AE to the Cary CAD-211AE, which should allow me to control the Violons a little bit better.

I named this system "Southern Lights" after Eliotswede's Acapella Violon system ("Northern Lights"). After all, i'm in Australia!

-- Old description below --

Years ago I became aware of the sweet combination of Cary amplification and ProAc speakers. It has been my intention for a long time to replicate this system and I finally got the opportunity to build my dream system from scratch.
Read more...

Components Toggle details

    • Acapella High Violon Suboktav
    3 way speaker with plasma tweeter, horn midrange, and conventional woofer. The most astonishingly natural sound I have ever heard. Sounds seem to emanate from thin air, free of distortion and coloration. This picture was taken next to my old ProAc D38's.
    • Cary Audio Design SLP-05
    This is an outstanding preamp with faultless sound. It takes forever for the tubes to run in. The first time I powered it up it was shockingly harsh and unmusical, but this settled down after 24 hours and is now gone.
    • Cary Audio Design CAD-211AE
    110W of push-pull triodes. Incredibly grunty.
    • Marantz RC-9500 universal remote
    The HT and 2 channel systems are tied together with this programmable remote. One press of the button starts a macro which ensures that all the correct settings are chosen.
    • Acrolink Mexcel 7N-S9000
    Simply unbelievable transparency
    • Acrolink Mexcel 7N-A2070 XLR
    Astoundingly transparent. With my last cable I was wondering where the midrange had gone. Well, now it's all back :)
    • Microseiki BL-99v
    Micro-Seiki BL99V turntable with vacuum hold-down.
    • Lyra Lyra Dorian
    Lyra Dorian cartridge
    • SGR EL30S
    SGR EL30S solid state stereo amplifier, 300W. For bass duties only.
    • JL Audio F110
    Pair of JL Audio F110 subwoofers.
    • DEQX HDP-3 preamp/processor
    The DEQX HDP-3 is used to measure the system and will be removed from the loop as soon as development is done.
    • Playback Designs MPS-5
    SACD player.

Comments 83

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Owner
Thanks Jack, you are right - the DEQX will introduce delay of its own. I did not think of that. Thanks to your response, I had to google up some audio delay circuitry, to see whether it would be possible to integrate that into the crossover.

I have evaluated the DEQX several times now, and I can safely report that I DO NOT LIKE what I hear. Against my SACD player, there is a loss of resolution and dynamics, but this is nothing compared to what happens when you put a top flight vinyl system in front of it. The DEQX simply falls way behind. If I say that the performance hit is 10% with my SACD player in front of it, it would be closer to 30% with my friend's vinyl setup (Basis Debut Vac + Vector 4 + Transfiguration Orpheus + ASR Basis Phono). On that system, the DEQX homogenized the sound to the extent that the vinyl source sounded only slightly better than the CD player.

Nevertheless, I had an utterly convincing demonstration on my own system and I know precisely where I would gain, and where I would lose. However being a typical neurotic audiophile I do not want to go backwards in any way, and I especially do NOT want to compromise the midrange/treble resolution that I paid good money for.

At this stage, all I can tell you (as a fellow Acapella Violon owner), is that the midrange/bass crossover is very poorly sorted. There is room for improvement. I don't know if you are happy with your bass or not, but I'm not happy with mine.

amfibius

Your experiments with the DEQX are very interesting! Please keep us posted.
Considering the pros and cons of the DEQX system, it would seem that the best approach would be to have it in the signal path in front of the bass unit only but I am not sure whether it would serve its intended purpose in this configuration. The DEQX by itself introduces a few microseconds of delay, which is the opposite to what you would be trying to accomplish. To time align the midrange/tweeter with the bass driver, you need to introduce some group delay to the midrange/tweeter section, which means you would have to use the DEQX in front of horns.

kotjac

Owner
Rushbattle, yes I am planning to run the DEQX in the bass only, but I will only do this eventually :) I was lucky enough to have Alan Langford (one of the DEQX developers) come to my house for a demo. He set it up so that it rolled off the midrange sharply at 500Hz and time aligned the mid/tweet to the bass unit. We compared that against the uncorrected midrange. The difference was massive - both the bass and midrange became so much clearer. This has convinced me that the midrange/tweet would benefit from steeper slopes than what it has currently.

My plan is to use the DEQX to find the point and slope for the midrange/tweet, and then make an active crossover to suit - thereby removing the DEQX from the signal path. So yes, your suggestion is a very good one.

amfibius

Have you thought of using the DEQX with the bass only? It sounds like you would retain more resolution that way. I bet your midrange will have much more resolution without all the processing and it's output should have little interference with the bass. Just a thought...

rushbattle

Owner
System edited: edit: description changed.

amfibius

Owner
A DEQX in my system.

Longtime Audiogonners will know that I have been trying hard to fix the bass on my speakers. The chief complaint is that it is muddy, indistinct, sluggish, and there is not much of it. It does not match the incredible articulation of the horn and tweeter. I have tried bi-amping, tried a Paul Speltz autoformer, tried mono-amping with a solid state amp, and (as above) reversed the phase of the bass box. They all help somewhat but does not really alleviate the problem.

I have been fiddling more with this system, and I should report an experience I had recently with a DEQX. For those who don't know, the DEQX is an amazing box of tricks that functions as an active crossover, can correct for phase anomalies, can correct group delay, and can correct for frequency anomalies caused by the room. The catch is that it redigitizes the analogue signal and outputs to multiple DAC's. Of course, you could feed it a straight digital signal via AES/EBU but I am using an SACD source with a view to vinyl in the future, so I was concerned about its analogue performance.

These are the measured frequency responses of each driver:

* Tweeter: High passed at 5kHz, steep crossover (48dB/oct?)

* Midrange horn: Low passed at 5kHz, first order crossover (6dB/oct), high passed at 500Hz, 2nd order crossover (12dB/oct).

* Bass: Low passed at 450Hz, 1st order crossover (6dB/oct).

As you can see from the above slopes, the bass box bleeds significantly into the midrange (it is -6dB at 900Hz), and the midrange horn bleeds into the low bass (-6dB at 375Hz). These are the *measured* crossover slopes (incorporating mechanical and electrical rolloff).

To cut a long story short, we set the DEQX to do the following:

* Profile 1: Midrange horn: High pass at 450Hz, 60dB/oct Linear filter, Bass box: Low pass at 500Hz, 60dB/oct Linear filter. RESULT: obvious and immediate improvement in the bass. Now became much more articulate, individual notes were more defined. Lower piano fundamentals were obvious and no longer murky. However, sound became too thin and lacked body.

* Profile 2: As above, with a 1.5ms Group delay to the midrange/tweeter. RESULT: Immediate improvement in perceived bass speed and overall coherence. Bass was also much fuller and louder. I did not initially understand why and how, so it was explained to me.

* Profile 3: As above, but corrected for room frequency response. RESULT: By this stage, the speaker was far more linear but the high bass and low midrange still sounded thin. This filled out the body by a tremendous amount, and the speaker now sounded natural.

It's not all good news though. The DEQX definitely knocks down overall resolution a notch or two, dynamics and inner detail also suffer. The question is whether the gains offset the losses, particularly when I move to a high end analogue rig.

amfibius

Owner
I should probably clarify that the above experiment was suggested by another audiophile (Mark, are you there) who visited me. One of the benefits of having a community of audiophiles in your town :)

amfibius

I tried the same thing with my Avantgardes Amfibius - actually - there is a REVERSE switch in the subwoofer so you can try it on the fly and learn fro the experience.

At the beginning, the sound is "different" but ended up to normal settings after some weeks of experimenting.

I would suggest you to try different speaker localtions in order to set the bass driver at its best, worked with my speakers.

Cheers,

Fernando

flg2001

Owner
Been experimenting more and more with this system. Because the speakers can be tri-wired, it is possible to change the phase of the midrange driver relative to the bass driver. All you need to do is swap the +/- on the cable that goes to that particular driver.

The results are interesting to say the least. With "recommended" settings, the bass is poorly defined and there isn't much of it. With the +/- swapped across the entire system, the bass improves markedly but the soundstage becomes constricted. My next experiment was to put the bass driver out of phase and wire the midrange in phase. I was expecting to get the bass improvements with preserved soundstage but no - it sounded all disjointed and wrong.

Speakers are back at factory settings. At least it provided me with an evening of free amusement!

amfibius

Owner
Joey I have no idea what kind of amps are best for your Martin Logans as I do not know anyone who has them!

The 805AE's are VERY good value here in Australia thanks to strong AU$ against US$. So it is hardly worthwhile here to get the 805C when the 805AE can be had for a small premium. But for what it's worth - yes I think the 805AE's are better. You have the choice of using 845's or 211's as the output tube which makes a huge difference.

The biggest difference with tube rolling comes from the input 6SN7's, followed by the output tube. Rolling the 300B will yield a difference but not worth the cost. Far more cost effective to change the input and output tubes.

BTW I know you have an SLP-05 as well. You gain the most difference by changing the tubes on the preamp, especially the input tubes.

amfibius

Amfibius,

I am running a pair of Martin Logan Summits and think that the SET 805 are perfect to run the panels while the bass woofers are handled by their own amps. Do you feel that the AE is worth the price over the last generation 805C?

And which tubes have you rolled into the 805 that you felt were a good match and yielded good improvements?

Thanks!!

Joey

joey_v

Owner
Hi Joey, thanks for the message :) It is a difficult question you ask, because you have to give something up to get something else (and i'm not just talking about money!!). If you have the speaker for it, the 805AE will keep you perfectly happy but unfortunately those amps do not have enough guts to drive the Acapella's.

The 211AE has a much richer midrange, and more authority from midbass down. The soundstage is noticably wider (but no deeper). Macrodynamics are a huge improvement, although you take a step back with microdynamics.

The 805AE has an amazing top end, so much more liquid and listenable than the 211AE. It also seems more transparent. While the 211AE is no slouch on its own, you only need to listen to the two of them side by side to realize that the 211AE seems to have a slight haze over it.

I will be moving to a bi-amp setup and when I do, I might switch back to the 805AE.

BTW I am planning many changes to the system in the coming months.

amfibius

I followed your journey from the Proacs to the Violons and from the 805AE to the 211AEs. Fantastic journey! You think the 211 are worth the upgrade from the 805AEs?

I'm hoping to acquire the 805 not too long from now for my panels.

Joey

joey_v

Owner
Flg2001, it is much less of a problem now that I have moved the speakers even further out since that photo was taken. Also, for critical listening I lean a couple of pieces of acoustic foam on the screen.

Tabl10s mate, when I listen I have a hunting knife to fight off the crocodiles :)

And speaking of dangerous animals ... a surfer got his leg bitten off by a shark a few months ago just a couple of km up the road from where I live.

amfibius

Since Australia has some of the most dangerous creatures, do you do listen much with the lights out?

tabl10s

Very,very nice.

glenfihi

Nice system amfibius - just wondering if the screen is not reflecting some of the beautifull highs your Violons deliver...

Enjoy the music

Fernando

flg2001

Hi Keith,

I will email you some photos of the Basis turntable. I have removed my system until such time that it moves into the next, and quite possibly final, phase (famous last words). The concepts will remain the same (very efficient single driver speaker augmented in the bottom octaves, single ended triode amplification, vinyl source) but some of the gear will be different.

Looking forward to your analog setup.

Aaron

drajreynolds

Owner
Thanks again Aaron. What happened to your system on Audiogon? You removed it? I was hoping to find some pictures of your Basis turntable there.

And thank you for the other recommendations. I did look into the Kuzma and you are right, not represented in Australia.

amfibius

Owner
System edited: Pictures updated

amfibius

No worries Keith, happy to help out wherever possible. I can't get very excited about the DPS2 turntable I must admit but it is the only thing Murali can offer besides the big Continuum Criterion so no real surprises there.

The rest of his recommendations are pretty solid although I suspect the RCM Sensor Prelude IC phono stage at $2950 will match the Einstein phono blow for blow and at less than half the price. The RCM gives an original Peter Mares Connoisser Definitions phono stage a very good run for its money. A shootout could probably be organised in your system when the time comes if Murali is willing to take part in the exercise and if you are willing to buy the one that truly sounds better to your ears. Heck, we could even do it double blind if you like.

If you wanted a suspended turntable I may be willing to part with my Basis 2800 vacuum at the right price. It sounds great on any stable platform thanks to its oil damped suspension pods. The vacuum platter will take care of any record warps and guarantees a super low noise floor and provides an ideal flat tracking surface for any cartridge. I am sure the boys from Continuum could make up an adapter to marry the Copperhead with the Basis or you could track down a Graham tonearm which would be a plug-and-play scenario.

I wouldn't be too concerned about a turntable manufacturer not being represented here in Australia, there isn't a huge amount that can go wrong with them. Just be sure that the company provides excellent customer service in the unlikely event that anything does go astray (motor or bearing issues).

Other turntables, besides Acoustic Signature Mambo, which personally interest me include the Brinkmann Balance (see Reference AV in Melbourne for this), TW Acustic Raven AC from Germany, Red Point Audio Model D from the US and Kuzma Stabi XL from Slovenia (the latter three still not represented here in Australia to the best of my knowledge).

It is worth taking the time to get it right first time around rather than upgrading in the future, especially in a country like Australia where the resale value is typically poor.

Good luck with everything,
Aaron

drajreynolds

Owner
Just got off the phone with Murali. He recommends: Airtight PC1, Copperhead tonearm, DPS2 turntable, and Einstein phono stage. He felt that the Copperhead arm is superior to the Schroder (yes I know that he is a major shareholder of Continuum, but I have always been impressed by his impartial advice). He thought the Verdier was an excellent t/t as well but cautioned that they are not represented in Australia.

Looks like another trip to Sydney is on the cards!

Thanks once again for your post Aaron, I have taken your advice on board.

amfibius

Hi Keith,

I feel your pain regarding the Schroeder waiting list, was almost going to join it at one stage. Judging by my last visit to Continuum they are well and truly on top of production now. The wait time should be minimal, a good thing if you have a gorgeous turntable and other toys sitting idle.

The other advantage of the Copperhead over the Schroeder, leaving any sonic issues aside for now, is the fact that the Copperhead can easily accomodate a wide range of cartridges whereas the Schroeder seems a little bit cartridge specific from my understanding, perhaps I am wrong here.

Also, the ability to easily adjust a tonearm's various parameters (VTA, VTF, azimuth, antiskating, etc) is very important, even if you only ever do it once. The Copperhead appears to have the edge in this department.

Unfortunately, I don't have any experience with the Audio Research phono stage paired with the AirTight cartridge. I am sure that the flexibility of the Audio Research phono stage will more than accomodate this fine cartridge but whether or not this is truly optimum you will not know until you try a few alternatives, not always easy to do in our part of the world.

I am lucky in that my cartridge and phono stage come from the same manufacturer (ZYX) so the synergy is about as good as it gets and quite possibly so is the sound as a result.

I am quite confident that the AirTight is a fantastic cartridge but in my experience the performance difference between the very best MC cartridges is less significant and more a matter of personal taste than finding an appropriate phono stage for your particular cartridge.

If I was in your shoes right now and assuming that getting maximum pleasure from acoustic music (particularly classical) is your number one priority I would go for high-mass, non-suspended turntable with excellent speed accuracy/stability, a Continuum Copperhead tonearm, a top of the range naked body ZYX cartridge and a ZYX Artisan phono stage. I would locate the small phono stage very close to the rear of the tonearm and use a single short run of cable from cartridge clips to a pair of the best RCA plugs (Xhadows). This avoids the heavy shielded cable braid and cable mounting block and the run of low level signal cable is as short as possible (a very good thing in my book).

According to one keen analog fanatic the aforementioned rig when setup both in my system and in his system (with a cheap Jelco tonearm in place of the mighty Copperhead I might add) was MILES ahead of an SME 20, SME V, cheaper Clearaudio cartridge, Audio Research phono stage rig which was set up at a well known dealer's showroom. He ended up buying the SME which proves that performance isn't always the single deciding factor.

Sorry for the long and unavoidably biased post, but if I felt dissatisfied with my own analog choices then I would be on the hunt for something else and not strongly recommending it to those I count as kindred hi-fi spirits.

I am sure you will achieve amazing sound whichever way you go but just be sure you don't spend more than is necessary to get there since that money could go towards the purchase of more music or perhaps proper support for your new analog rig.

All the best,
Aaron

drajreynolds

I've not listen to Cary, they are not represented in Sweden.

If I where to try another amplifier to my Acapella I would look at Einstein, CAT or Jadis. Maybe go all out and also use CAT SL 1 Ultimate as preamp since it has a good RIAA.
But I'm really satisfied with my AudioNet setup :-)

mickep

Owner
Thanks again Aaron for your contribution. At the moment I am undecided between the Schroder and the Continuum Copperhead. They are both roughly the same price but the Copperhead's advantage is that I can actually buy one, and not go on some waiting list!

What do you think of the Audio Research, paired with the Airtight?

amfibius

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