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[Bob in St. Louis]

Two observations:

#1 The wings don't appear parallel. We can ask Jim to put a square on them, but it appears they have a couple of degree angle to them.

#2 Could the holes simply be a place to run the wires through for a cleaner appearance?

Bob

[JohninCR]

OK, I'll just have to go on your word about whether or not there's a resonance.  At what depth or depth to width ratio do we need to start being concerned with resonances on the backside using these types of shapes?  There's already enough to worry about with reflections and diffraction, so having one less concern is good.  A rule of thumb would be nice.

[MJK]

Personally, I would not even consider a resonance as a possibility in the baffle sizes being discussed. I would just go ahead and design the baffle, wings, and sides without even thinking about a potential resonance.

[JohninCR]

Personally, I would not even consider a resonance as a possibility in the baffle sizes being discussed. I would just go ahead and design the baffle, wings, and sides without even thinking about a potential resonance.

Now I'm thinking there must be 2 MJK's, because not that long ago MJK told me that no matter the splay angle of wings resonance would result.  Will the real MJK please stand up , or has something changed your position?  At the time I was going with GM's rule of thumb of at least 1" of splay to 6" of depth.  Also regarding open backed boxes, I know some of the ones I build early on had a hollow resonant sound, not just the lack of coherency in the ambiance created by the rear wave that can result from early reflections and diffraction that occur with different structures behind the driver mounting baffle.

[MJK]

Probably what I was trying to say was that non parallel sided enclosures can still have a resonance, taper or expansion in a volume only changes the frequency of a potential resonance. People seem to believe that if they make an enclosure volume with non parallel sides that all potentail for a standing wave is removed, this is not the case it is just harder to calculate the frequency. People building BLH often put a sloped wall behind the driver because they believe it will avoid a resonance appling pressure to the back of the driver and smearing of the sound.

[Frank McCrea]

Guys,,,
Tom (the seller) is a friend of mine, the holes in the corner pieces were drilled to pass the wires through.
Hope this helps,
Frank

[maxro]

...the holes in the corner pieces were drilled to pass the wires through.

Well, I guess that ends the discussion... Or does it?

Perhaps this Helmholtz trap idea could be useful for the more usual deep and narrow U baffles, which I think we could all agree, have resonances. I had thought earlier about such an idea for use with a so-called Ripole. An acoustic notch-filter, rather than an electronic one. 


How come I'm not getting email notifications of new replies to this thread? The box is checked.

[JohninCR]

Oh well it was a fun idea, though probably not very practical because tuning a helmholtz trap to a very narrow effective range in order to damp a resonance may prove to be an excercise in frustration.  OTOH it did give me some useful ideas for putting otherwise wasted volume to use as part of the much longer pathway to route some of the lowest frequency content of the rear wave in order to offset the dipole cancellation.  The Helmholtz tuning is an important aspect in capturing only low frequencies, since at higher frequencies 1/4 wave resonances of the extended pathway will come into play. 

Here's how I put this idea to use, which I call an OB/RLH (single or coax driver in an open alignment that doesn't need EQ or a sub).  Further development has been on hold for a year, because I've been unsuccessful in soliciting advice regarding how to optimize the alignment.  Also, I was waiting for a new 10" or 12" coax to come out enabling the performance I get with the 15", but in a much more compact form.  The drivers used are the Hawthorne coax and the B200.  I also built a pair using the Selenium coax 15.  They all work very well, although the B200 is tuned higher since it just can't move enough air for the really low stuff.

[planet10]

Some comments,

1/ Russell, Lou may have influenced this design, but i think most of it was Quest in Vancouver. When i talked with Lou about the SupraVox he was of the opinion that no tweeter was needed (but then he does tend to flip-flop) Edit: my misunderstanding. Quest had nothing to do with either speaker, and Lou did help out with the SupraVox, nut not the Visaton i heard. A couple names of vendors i do not know were being tossed around, and i somehow got the impression it was one vendor not 2. My sincere apologies.

2/ I had the opportunity to listen to the less expensive version of these yesterday with a Visaton B200 instead of the Supravox. Tom said that with the Visaton the speaker was at 85% of the SupraVox. I'm sad to say that as configured the speaker was unlistenable. Disconecting the tweeter transformed the speaker something dramatic. They were now what you'd expect from a modified B200 -- quite good (these have my phase plugs installed and a couple coats of C37 (can't speak for the C37 on these, but on the CSS FR125 it transforms them -- not so much on FE127))

3/ these really need to be bi-amped, the Visaton sounding better with relief in the low frequencies. Check out J&Gs implementation on diyAudio, a whole lot more thot has been put into those.



dave

[planet10]

Martin,

Don't know about the FEM, but on the similar Visaton baffles, there was definitely some resonance that was quite distasteful... and a bit got thru to the front. This was not evident on my unfolded baffles.

dave

[Frank McCrea]

Some more comments,,,

1/ Actually, Quest didn't have any input into the design or build of these Visaton OB's. This was simple a prototype that Andy and Tom had quickly assembled so that a few people in Vancouver could have a listen, Quest may have been one of these people.

2/ To my ears I wouldn't exactly call them unlistenable. That being said they did sound better with the tweeter disconnected as mentioned. In terms of the comparison between this Visaton's and the Supravox, for me it wasn't even close, the Supravox's being one of the best speakers I've ever had the pleasure of hearing.

Hopefully with a little encouragement Tom and Andy will continue to play (fun) to make this a better speaker.

Best, Frank

Some comments,

1/ Russell, Lou may have influenced this design, but i think most of it was Quest in Vancouver. When i talked with Lou about the SupraVox he was of the opinion that no tweeter was needed (but then he does tend to flip-flop)

2/ I had the opportunity to listen to the less expensive version of these yesterday with a Visaton B200 instead of the Supravox. Tom said that with the Visaton the speaker was at 85% of the SupraVox. I'm sad to say that as configured the speaker was unlistenable. Disconecting the tweeter transformed the speaker something dramatic. They were now what you'd expect from a modified B200 -- quite good (these have my phase plugs installed and a couple coats of C37 (can't speak for the C37 on these, but on the CSS FR125 it transforms them -- not so much on FE127))

3/ these really need to be bi-amped, the Visaton sounding better with relief in the low frequencies. Check out J&Gs implementation on diyAudio, a whole lot more thot has been put into those.



dave

[planet10]

1/ Actually, Quest didn't have any input into the design or build of these Visaton OB's. This was simple a prototype that Andy and Tom had quickly assembled so that a few people in Vancouver could have a listen, Quest may have been one of these people.

My mistake... i don't know Andy or Quest at all so confused them together. The amp was Quest?

dave

[Frank McCrea]

Bingo 
Frank

[lankester]

Thanks Frank.

Dave got the  facts wrong; Quest is a first rate amp builder/designer.  I have been listening with absolute delight to his and Tom's recent 2A3 amp with black gate caps and Tango iron. Simply disappears.

I am at a complete loss however, as to why a person would take a picture of someone else's prototype/experiment and crucify them on this forum, without a heads up or approval from the builder.  Sounds like there is an axe to grind......These speakers were not listed on any web site for sale with any type  of description or price point stating that they had any qualities of any kind, good or bad.  Tom and I were looking for some feedback from some fellow audio enthusiasts.........well, we got it!  I am still not sure why you said in a recent email to Tom that they "had promise".

I guess you get what you pay for.  The Supravox drivers obviously are superior to the Visitons, but then they should be for 3x the price.

Andy

[planet10]

I have added an apology to my 1st post in this thread where some confusion on my part lead me to mis-speaking.

dave

[planet10]

Dave got the  facts wrong; Quest is a first rate amp builder/designer.  I have been listening with absolute delight to his and Tom's recent 2A3 amp with black gate caps and Tango iron. Simply disappears.

Yes my mistake... your name & Quest's were being tossed about and not knowing either of you i thot you were the same person. I have been informed of my error.

The 2A3 was indeed a nice amplifier except for the pervasive low level hum -- more noticable on the more efficient Fostex than on the Visaton baffles. It is also a very pretty -- in a traditional style -- amplifier.

I am at a complete loss however, as to why a person would take a picture of someone else's prototype/experiment and crucify them on this forum, without a heads up or approval from the builder.

Crucify? Honest yes. The speaker as presented was unlistenable (IMHO) and did a disservice to the quality of the Visaton B200. The strength of the comment no doubt comes from the expectation engendered by the comment 85% of the performance of the SupraVox. Once the tweeter was disconected the preformance of the loudspeakers was dramatically better. The only axe i have to grind are that i have been promoting the Visaton since i had the 1st pair in North America, and i would not like to see it put in a bad light -- which certainly the speaker with the tweeter did. The other axe might well be the apparent hyperbole in the advert linked to in the original post, but that tone was set in the thread long before i got here... And why would i require the approval of the builder to voice my impressions? Your product is your calling card. The sonics are what counts.

I guess you get what you pay for.

If that is interpreted as something that costs more always sounds better that is certainly not the case

The Supravox drivers obviously are superior to the Visitons, but then they should be for 3x the price.

I would be surprised if the weren't -- i haven't heard them so i can't say from personal experience. (as an aside the modified Visatons -- sans C37 are $420 CAD/pr, Mu understanding is that the SupraVox cost more than $100 USD. I have heard drivers that cost 10x as much as the Visatons that did not sound as good).

My beef is not with the Viastons, but with the sonics of the package -- which with a bit of experimentation -- proved to be the execution of the tweeter integration. The degree to an extent that they should not have made it out of the shop as they were. Andy, you are not a diyer, you are a professional, i expect better of you.

dave

PS: i don't post often on this forum, but where i usually hang out my comments would be construed as constructive critism. I do feel that the fellow (who posted in this thread) who ended up with the SupraVox baffles got a bang up bargin, i encourage him to see what he thinks with the tweeters on those disconnected as everything i have heard about the SupraVox FR indicates that they do not need a tweeter.

[lankester]

I read the posts......there is nothing on them about the visitions being quoted as sounding "85 percent as good as the Supravox".

Sheesh! 

All this because we tried out a tweeter that we canibalized from another set of speakers to give the speaker some extra "air" in the top end.  Might try a different value for the filter.

Sorry, this will be my second and last post. I really can't take all of this so seriously.  It is supposed to be fun.

Thats what got me in to this hobby and thats what will keep me in.  Off to my day job now !

Andy

[RAW]

This speaker you are refering to by the builders here in Vancouver may just see the light of day in the very near future.

I personally spent several hours talking to them here over the design that is in the photo above.

Will have to wait and see aa

[chrisby]

I read the posts......there is nothing on them about the visitions being quoted as sounding "85 percent as good as the Supravox".

Sheesh! 

All this because we tried out a tweeter that we canibalized from another set of speakers to give the speaker some extra "air" in the top end.  Might try a different value for the filter.

Sorry, this will be my second and last post. I really can't take all of this so seriously.  It is supposed to be fun.

Thats what got me in to this hobby and thats what will keep me in.  Off to my day job now !

Andy

Andy - while we've never met, I feel compelled to offer some remarks on the subject;

The "85%"  comment was in an earlier e-mail from Tom to Dave, prior to the speaker's surprise visit to Victoria.   


Thanks to Frank's gracious offer, a group of 4 were convened for an afternoon listening session, all of whom have decades of listening, and more than a few years of DIY amp and speaker building experience.  We know what we heard that afternoon.

Quest's amp was very nice indeed - a very tidy piece of work, and sonically a different presentation than the Welborne DRD45's, but that's to be expected with a totally different topology and parts complement.  The matter of preference between the two amps is not germane to the topic of this thread. 

The focus of our afternoon was the sound of the 2 pieces together, and as I'm sure you're aware from attending more than a few of this type of session,  discussions among the group tends to bounce all over the place. Without a program list, it can be easy to lose track of the contribution of each design / build  participant, or the inspirational source and evolution of the project.
 
As Dave has mentioned, we've had experience with the B200 going back several years,  and the magic of which the unassisted driver is capable is certainly compelling - particularly in consideration of its price compared to Supravox, Fertin or any other of the European esoterica (none of which I've had the pleasure of hearing) . This is one helluva bang for buck driver, particularly when the cost of a decent sounding pair of baffle can start at than a full sheet of plywood.

It can be quite a tricky undertaking to extend the performance of an already exemplary driver such as the B200 beyond it's "magic zone", regardless of "enclosure" format, which is why many playing with "full range"*  tend to avoid the attempt.  A "seamless"  implementation (good luck!) can often cost (several times) more than the base driver itself. 

To repeat what's been said,  what we all heard in the Visaton system was a lack of coherency as well as overly bright upper midrange. Based on experience with the B200, our intuition was that without any apparent band-pass filtering, the effective crossover point for the ribbon might be too low, the spacing between drivers too wide and their dispersion/ lobing patterns not fully integrating at our listening distances of approx 8-10ft.   As a result, soundstage width/depth and imaging stability suffered when compared to with the ribbon disconnected.    "Unlistenable"  with the tweeter running?  Dave probably regrets that unfortunate expression, but there was no doubt that even though lacking high end extension, they "made more sense" without. 

You might want to revisit the crossover points, and consider locating the ribbon closer to the B200 to improve integration through the pass band.


Keep trying to have fun with the "hobby", but as to the comments regarding woodworking/ finishing quality, if this particular pair was a prototype, it might have been better to hold off attaching a corporate badge. 

[celebrat]

Hello again everyone.
I am the one who purchased the Supravox Open Baffle Prototype that I believe started this thread. I said I'd get back here and post after they were up and running, and here I am. I apologize for this long post. If you don't wish to read it all, the next 2 paragraphs sum it up w/o the gory details.

To make a long story short; I am one lucky guy. These speakers are incredible. They are the best speakers I have ever personally heard anywhere. Now that the suspense is over let's get into some particulars.

First let me say that Tom has been one of the most helpful and knowledgeable gentleman I have had the pleasure of "meeting" (phone and the internet constitute meeting for me in this day and age) in this hobby. He is a wealth of information and is willing to share what he knows unreservedly. It is clear to me that this has been a true labor of love for him and his associates. This is not about money. They are bunch of audiophiles who have shared their experiences and have come up with a speaker that I believe will change this hobby, not to mention the entire audio industry. This speaker is that good.

I want to give a bit of background as to where I have come from so the forum may get a sense of how these sound with respect to other speakers.

First, I am not a DIYer or very technical. I have had a fair amount of exposure to various speakers and systems.
In chronological order I have owned:

Wilson Benesch Act 1s - A very nice speaker, very coherent, great imaging limited bass and dynamics

Talon Audio Khorus - I hated these speakers ,Terrible
midrange

Genesis V - good speaker, decent imaging, good dynamics deep but boomy bass

Quad ESL 63 - I loved these speakers with the exception of limited volume, low bass, and dynamic capability.

Apogee Mini Grands - Nice speakers but sucked up power and boomy bass

Soundlab A3's - Great Speaker good on everything but dynamics/ Ultimate loudness. Not as clear as the Quads

The above eventually led me to Avantgarde Duos. I really like the Duos. To me they are musical.  More musical than any of the above. Bass was tough to integrate. Imaging was good not great, but they made me listen to music and not the speakers. A personal first. I kept these speakers for more than four years

From there I went to Zu Definition Pros after auditioning them side by side with Duos. The Zus are more coherent, better imaging and absolutely staggering bass. Not vastly superior, but better IMHO

Along with these speakers I have heard Utopias, Wilson, Revel, Dunlavy, Duevel, Beauhorns, and more than I can remember.

I had read a bit about field coil drivers (Shindo Latour, Jensen) and was intrigued. When I got the Red Wine Sig 30, I stumbled on this sight and the open baffle got my piqued curiosity.

So, when I saw Tom's Supravox Open Baffles, I decided to take a chance and made the purchase with out hearing them. The last time I did that was with the Talons, so I was a bit nervous, but if they did not work out, I still have the Zus. The Zus are now on sale on Audiogon and I would appreciate it if people kept that detail to themselves until after they sell LOL.

These Supravox speakers are so markedly superior to any of the speakers I have heard before, that they are really hard to describe.

Imaging - Best I have heard. They completely disappear

Dynamics - Best I have heard

Soundstaging - Best I have heard

Musicality - Incredible... Best I have heard by far

Speed- Astoundingly fast... Best I have heard by far

Coherence - It is a point source

Bass - Goes down into the 20s...not as low as the Zus but the most articulate bass I have ever heard.

Well I guess that's about it. I feel like I am home for the first time.