Gravity Well Of A DarkStar

JoshK · « **Reply #80 on:** 3 Jun 2005, 11:40 pm »

Have you ever heard those Supravox's?

Dmason · « **Reply #81 on:** 3 Jun 2005, 11:51 pm »

Not the field coils, the 215 Signature Bicone, direct comparo to the B200. A very nice speaker indeed. Great for OB, lots of Xmax. $335 ea. Not superior to the B200. Different. The Visaton build quality eclipses the Supravox with its crappy sand-cast frame and money spent on shi shi machined brass magnet cover, Visaton gives you a cast alloy frame and big-assed monkey of a magnet with focussing disk....

If these two drivers were cars, the Supravox would be an older Peugeot 505 with leather, and the Visaton would be a brand new black BMW Z3 with an F-117 paintjob.

With contouring, the B200 is an animal. It is a faaaaaar more powerful, technically superior machine. In fact, with digital contouring, the B200 is any friggin driver you want it to be. An absolute perfect candidate for open baffle with digital contouring, and the combo is still about $250 LESS than the Supravox 215 Sig. With the savings you can then buy nice bass drivers, and some MDF, and have the whole buffet, with even a few bucks left over for beer.

ooheadsoo · « **Reply #82 on:** 4 Jun 2005, 12:10 am »

Doc, how far do the baffles have to be from the rear wall? Since there was some talk about running the baffle into the ceiling corner with some clever pipe design and what not earlier in the thread, I was thinking that maybe it could work on a small to medium triangle shaped baffle mounted in the corner as a "pseudo" (yeah, it's not even genuine pseudo) infinite baffle but still essentially dipole radiation.

Dmason · « **Reply #83 on:** 4 Jun 2005, 01:18 am »

No rule book on that. Depends on everything. Like all speakers though, they need to be away from the back wall. they fare better with corners, it seems. YMMV. Mine are about 36 inches out.

JoshK · « **Reply #84 on:** 4 Jun 2005, 03:31 am »

Have you ever measured the Visaton B200 for distortion? What is it's pistonic range? I am very intrigued by these drivers and wide/full range drivers but the physics doesn't make as much sense to me as narrow band stiff cone drivers do.

-Richard- · « **Reply #85 on:** 4 Jun 2005, 04:50 am »

The laws of physics and the aesthetics and art of sound reproduction
are not fully understood in absolute terms...if it was merely measurements
that secured our grip on great sound then that would be that...

Perhaps it is...ultimately...

But what is variable here is that we do not always know exactly HOW
to measure nor always WHAT to measure...in other words we can see the
correlation between some kinds of technical information and not
others...

I think that creates a space where art comes into it...and knowing how to apply
what you know with what you have to make it work..to make magic happen.

I am merely thinking out loud here...it is such a pleasure to be a part of this
unfolding leap into new areas of magical possibilities that I can not help
but get excited...

What Dan is giving us here is a chance to experience our youthful excitement
about audio all over again...to change our thinking from the acquisition of very
expensive superhypedcorporatecontrolledandsanctio ned audio gear to
experimenting with inexpensive DIY fun projects that never-the-less make an
assault on the highest level of audio life...

A certain inner space is necessary...that is what Dan is suggesting we
cultivate...that inner space will give us permission to experiment...to play
if-you-will with some new paradigms...just to poke a hole mind you through our
own conditioning of what we have been trained to believe the real life
of audio resides...Dan is putting that control back into our hands...and helping
us to appreciate and consider cottage industry one-on-one innovators like Vinnie
and Louie as the spectacular resource that they are...and Dan himself is giving us
a way to enter into this whole phenomena of singlewiderange speakers easily
with the least impact on our budget....or skill level as it now stands...

It is about a philosophy of life...of our musical life to be certain...but not just that...
it is about how we solve problems and bring energy and creativity back into our
lives again...

Warm regards -Richard-

Dmason · « **Reply #86 on:** 4 Jun 2005, 05:21 am »

Josh,

Suddenly you seem resistant, like you are considering a pair of these German wonders, but are looking for ways to talk yourself out of a decision; perhaps looking for the thing that will allow you to decide not to decide....Screw the pistonic range and distortion figures. Understand this: I measure with my EARS, my Mark II Tympano Cochleometer. If I hear Real Music, great. If things suck, I move on. Simple....This stuff works. Isnt that enough? This is a gift, an opportunity to slap together a sandwich and start working on your very own world class recipe for sound. Four people I know like what they hear in my place, they want me to build them sets for their homes, different styles, same design. Most people would be registering a name. I am sharing my findings. The more this thread advances, the more I plan on sharing. This should suffice. Please dont ask me to toss my protocols and test. That is for audiophool vivisectionists. This is about Music. The physics is dead simple, BTW.

I have to say that if one's thinking is confined to multi driver arrays, solely because that is what they understand, then no amount of discussion or explanation will necessarily move them. This is ALL about thinking WITHOUT the box, not outside of it.

You realize you are indirectly asking if wide range drivers actually work. The design concept for this speaker about eighty years old. It is virtually unchanged from the original Siemens, or Philips model of "full range" drivers, for theater, as I mentioned earlier in this thread. Many other examples are out there. What is special is what Visaton has managed to accomplish with this thing. The B200 is becoming a virtual legend in Europe, and hopefully it will catch on here, including yourself. As always, NIFE and YMMV. (Time for the usual disclaimers)

powerbench · « **Reply #87 on:** 4 Jun 2005, 06:53 am »

I am awaiting my Omerga Mini-me's arrival but i am going to order the b200

what the heck!!
With OB in a 14x16 ft room with the ClariT and Modded 3960 ...few Q's...what material

,how big/dimensions?

Do i need various layering

?Anything else???? im looking for the Simplest Ultimate Experience!!!

Hey if they dont work ill sell them...

Hey Mark (the other canadian Mark))ill be contacting you as soon as the Me's arrive.....wait.wait,wait

not Louis fault just customs...

barfind · « **Reply #88 on:** 4 Jun 2005, 07:47 am »

I can echo Dans words. I have had the B200's playing in my room since Jan this year. I just listen to music now. I dont have to worry about looking at different sites thinking I might find the right speaker for me. This thing is the real deal. I have friends over from the local HiFi club, and they are blown away by how lifelike and musical this driver is. Mine has had a lot of exposure on another site, and everyone that has tried this driver has been impressed, very impressed. I am in the happy situation of not thinking about anything execpt lisening to music.

Nigel

JLM · « **Reply #89 on:** 4 Jun 2005, 02:05 pm »

powerbench,

A willingness to experiment is the key here. One classic OB design is 31 inches by 39 inches with the driver 8 and 10 inches from adjoining edges. The bigger the baffle the deeper the bass. Some have added continuously hinged wings that can be folded back to provide support and additional effective baffle size. Digital EQ will probably do more than domestically acceptable baffle sizes.

Materials can be anything. Rigidity is less important as the baffle is under almost no pressure. So I doubt layering is needed at all. Some report that reflection of one driver from the baffle of the other can be a significant consideration due to the size of the baffle and can be addressed by adding absorptive material to the front of the baffles. Again, be open to experimentation. The cheapest materials will provide you with a full taste.

Something we haven't discussed here is the flexure/movement of the baffle from the momentum of the cone in motion. So increased weight and a reasonable degree of stiffness would be good. If you pad the baffle, it won't have to look like anything (I'm thinking of 3/4 inch plywood or MDF as possibly being overkill here).

barfind · « **Reply #90 on:** 4 Jun 2005, 02:28 pm »

My baffles are 20mm ply glued to 20mm MDF. Very strong, but I have to say that they DO virabrate alot. I have taken the 12's out of my baffles to run the B200 by themselves, and the baffles still vibrate. I think some way to curb the baffle vibration would benefit the imageing. I was thinking of mounting the driver on a board just 250mmx250mm, and fitting this to a baffle with a 253x253mm hole where you want the driver to be situated. The plate holding the driver could be supported seperatly to the rest of the baffle. The driver should still see the whole baffle to make bass, but no vibration would be tranfered to the baffle.
This may or may not work, or no gains may be made, who knows. But I am going to try this and see if it makes a difference. The thing about OB's, is they are easy to tweek

Just thinking out loud........

Nigel

powerbench · « **Reply #91 on:** 4 Jun 2005, 02:33 pm »

Thanks for the reply its appreciated.I read some where also that the wings (for less of a better term)should be much less than thand the width of the centre board which may also keep the thing upright.

mcgsxr · « **Reply #92 on:** 4 Jun 2005, 03:23 pm »

Well, I got them running around 3pm yesterday, and have let them run since, at varying volumes. I want to be clear, that I am fully in the "this is an experiment" camp, so when I post my comments, I hope that people understand that this is a work in progress, and I see room for improvement in a couple of ways - that said, I absolutely see that there is something interesting going on here, and it is worthy of continued experimentation.

First impression - wow, that is bright - I cannot imagine for the life of me, why anyone would seek to add a tweeter to this driver, running full range, in a baffle.

Next impression - hey, where's my bass? I am a junkie for bass, so that is often my response to many speakers, and it needs to be understood that my room is a nasty one for a null, right at the listening chair - when I approach the speakers, or leave the room to go upstairs, there is tons of bass, so it is not like they cannot make it, it is simply the room refuses to cooperate with most speakers in that fashion. I dragged out my sealed 12 inch sub, applied the 300w amp, and tuned it in. At present, I am going back and forth with the sub at 65Hz, medium volume, and totally off. This is an emerging situation, as this AM, there is much more bass in the listening spot, though still not enough for me...

Further impressions - good god, I have never heard strings and voice so naturally presented in my room before. Classical, jazz, light adult contemporary, anything with strings - violins, stand up bass, acoustic guitar etc, all just sing here. Male and female voice sound real. That part is great, and has not faltered at all, in the last 20 hours.

Still more impressions - wow, I have never heard tube rush in my system before. I can now hear some high frequency slush, during quiet sections in the presentation - my Hagerman Clarinet is otherwise silent, mated to the Bolder Teac.

Last impression for now - dynamic! I cranked it up a little this AM, less the sub, and when rim shots hit, or punchy snare drums come up, it really lights up the room. Good things are happening here.

So, my recipe is as follows (pics in a while, when my daughter goes for a nap, I will get out the digital camera) - baffle is cut 36x48 (wxh), and across the top, I cut an angle - it is 44 inches H on the outside, 48 inches H on the inside of each baffle. I rounded all edges with a 5/8 router bit, and sanded smooth after that.

I will measure the driver, but it is offset to the inside, and up higher than 50% of the H of the baffle. At this point, I do not notice a lot of baffle vibration (3/4 mdf) unless there are 30Hz notes blasting (Chemical Brothers...).

I played around last night with toe in, and vertical lean, and have reached something that sounds good so far.

Those who have read all my posts in this thread, will recall that I am taking the mostly hairshirt approach - full range, direct connection to the amp, no digital correction, no Xover etc. This was in order to determine, for me, if this is worth continuing with.

It is - next up, playing with adding resistance to smooth the frequency response.

So, so far, the net is this for me - I like where this is headed, and I do want to continue forging ahead - tips if you have any!

Dmason · « **Reply #93 on:** 4 Jun 2005, 03:38 pm »

And away we go!!

Nice notes, Mark. Maybe if you can get over to the Rat Shack in your 'hood, and pick up some 16-22 Ohm resistors for parallel. I found this an interesting result, and wound up keeping in I think 1 6Ohm even with contouring applied.

I like your observation that there is real bass hiding somewhere in your room, like a ghost, only coming out when your back is turned. This was exactly what I noticed. It also sounds like the real ghost is your basement. At least you HAVE a basement, - the ultimate speaker enclosure-

I have noticed that, if I am not wrong, an irregular shaped room is best for open baffle speakers, best, being optimal, the jury is out on that one.

mcgsxr · « **Reply #94 on:** 4 Jun 2005, 05:29 pm »

Here are some pics.

First up, a shot showing both baffles, in place, in the system - note that they dwarf the 32 inch Sony!

Next up is a close up of the right baffle - this is to show what I meant by the angle along the top. I used black allen bolts, so it really appears to float in a sea of mdf!

Here we have a visual of the open side of the basement - this is along the right hand side of the system, and shows why all the bass seems to run away! This is a really tough room to pressurize with bass (though my DIY ported 12 in a 4 foot box tuned to 23Hz can do it for movies...).

Lastly, here is a shot of the rear of the baffle - no hiding the warts with me! You can see why I want to buy a circle cutting jig... and how I simply bolted the drivers to the baffle. Also, you can see how I glued a couple of strips together, to act as a mount for the binding posts.

Dmason · « **Reply #95 on:** 4 Jun 2005, 05:45 pm »

Very nice! With all the angles, and the drop-ceiling, it all looks very artistic. An added bonus?

What's that behind the big chair, a louvered door hiding a hot water heater, maybe? That corner looks worthy of exploration. With baffles that size you should be able to get good things happening into the corners.

You do get to hear just HOW resolving T amps really and actually are with a set up like this. Clear, combining warm with analytical.

And thanks for the shots and captions, very helpful.

powerbench · « **Reply #96 on:** 4 Jun 2005, 05:51 pm »

Thanks for the pics Mark,maybe its an issue of 'breaking in -itis'with the B200s but heck thats quite a baffle size I think id have a hard time passing that one off to the 'significant other' without covering it with a dolie or designer print or something...

JoshK · « **Reply #97 on:** 4 Jun 2005, 05:52 pm »

Thanks Dan, I do appreciate you sharing your findings. FWIW, I may be asking more questions inadvertently but really it comes down to wanting to understand as well as anything. I ordered the pair of Ciare drivers to try out OB before this thread had taken off the way it had. Basically I have some other speakers already done and some on the drawing board as well.

I am not at all questioning OB design, but more how a single driver can really work full range. Of course, I DO trust my ears, after all I was a musician for a while not all that long ago. I am also a mathematician and I do believe in science and that things can be explained with it, although not always does our science explain everything well because of the assumption needed to make it simple.

Dmason · « **Reply #98 on:** 4 Jun 2005, 06:10 pm »

Musicianship and math are a good start. And the Ciares will give you an A++ insight to all this. I own some and love them. My son is adding them to his car, arguing that they are "car" speakers after all.

If you read Vance Dickasons' book on speakers, the physics of dynamic cone drivers is eloquently explained; just that this thread is not a good place to take time out to verify that these machines actually do work.

For a visit to the Wide Range Zoo, www.spectrumaudio.de will show all the different animals and their behavior in their natural (IB) environment. Hope this can help, certainly interesting. The Ciare is Wolfgang's favorite BTW, and gives up little to the Visaton.

nodiak · « **Reply #99 on:** 4 Jun 2005, 06:44 pm »

Nigel, are you using the 12's at all now? Are the B200's getting down to 70hz at least? That's my current xo for sub.

Also on the general OB idea, adding 4" deep sides doesn't hurt the sound at all in my experience, for these larger baffles like mcgsxr is using maybe 6" even (maybe worth an experiment). The point is you can keep the same width as a flat baffle by bending it, as the edge is the same distance away. Too deep sides give them selves away with a detectable cavity resonance. Also one of mine used sides that were only 30 degrees to the flat front, you could use any angle presumably less than 90 degrees, but that's just my assumption. Curved 1/4" ply laminates anyone?
Also I ended up lining the back of my ob's to help tame reflections. It's all room dependent at that point imo. I've only used OB's to about 125 hz, so am interested in this B200 discussion, Currently I use a single sub as it gave better response than stereo pair in my room, so I need a low xo point, 70 hz now.

Nice to see this OBism. Also there is quite a bit of info and experiments with OB's out there. Just google open baffle. Dick Olshers Basszilla (google it if interested) was a big influence for me as I like using bass drivers.

Don