[JLM]

Richard,

Thanks for your words of encouragement.  It is nice to know each other better and interesting to find out what different backgrounds we have.  You raise a good question regarding baffle size as it relates to room size.  At some point large baffles become semi-infinite and begin to block substanial portions of the higher frequencies contained in the rear wave.  For the "tipped up" frequency response of the B200 this could be an inprovement in taming the highs, but would also seem to affect imaging (I'm thinking here of depth of soundstage).  This is another good reason to provide digital EQ (so you can have a smaller, more domestically acceptable baffle size).

Dan,

Yes, the room is a speaker enclosure.  With OB/IB you eliminate the "other" enclosure.  Great speakers must begin with great drivers.  The B200 certainly seems to qualify.  But few drivers are ideal for a wide range of applications.  They can be made to work, and in some cases remarkably well, but audiophiles want better than that.  With the advent of cheap digital EQ and the simplicity of OB, I don't see a compelling reason to try to apply the B200 to anything else.  As soon as our house issues settle down (building one, selling one, moving, finances, stress) I plan on ordering a pair of B200s with EQ.

Mark,

I'm sure part of what you're hearing regarding imaging is the point source ideal of a single driver versus multiple drivers (as you add/subtract the tweeter).  I've found that OBs can provide more of a wall of sound versus the hyper reality of pin-point imaging, which is what I hear from live/unamplified performances.  The 8 inch diameter B200 should start beaming around 4,000 Hz according to laws of physics (but I didn't study law, did you?).  Unless you're very young or have canine blood, 4,000 Hz is pretty high (about 2 octaves from the upper limit of adult hearing) so the beaming is less of an issue than most would imagine.  I've noticed it with my whizzerless 8 inch drivers, but its not what I would call a major factor.  This gets into one of my standard rants regarding the marketing hype that we "need" 20 - 20,000 Hz (IMO 30 - 8,000 Hz or 8 octaves would cover at least 98% of what we hear).

ooheadsoo,

The triangular ceiling corner mounted baffle would have to be fairly large for the B200 if you're thinking about using it as an infinite baffle.  Rule of thumb is to provide 4 to 10 times the Vas, which for the B200 is 107 liters or about 1.3 cubic feet.  So the baffle would have to be at least 4 feet across.  Having the drivers mounted about 6 feet above the floor and angled down may not provide a natural presentation.  That brings you back to the wall/wall corner mounted baffle (open at both ends) that I proposed a few pages back.

[-Richard-]

Hi JLM,

I am about to build a version of the baffle and I am wondering....
in absolute terms...what is the least width baffle size that will work
with the B200 as an OB configuration...assuming I maintain a
height of 48 inches...can I get away with a 24 inch width and still
have enough of a surface to "hold" the lower frequencies?

I am working on a design that would allow me to lower and raise
the baffle at least 1 foot to see what effect that has...which would
also give the baffle legs for a corner application.

Assuming that the mass of the baffles surface plays an important
part as a kind of "sound board" (not unlike a musical instrument...
like a piano...or clavichord for example) will a 24"x48" board do it?

My room is 20 feet wide, 7.5 feet high, and 30 feet deep...a 1970's
style mobile home...and I removed a wall here and there to open
things up so it looks a bit more loft like...except that I have not yet had
the time to see if I can get more ceiling height by ripping down the
essentially dropped ceiling (how they built these things in the 70's)
and follow the natural peak of the roof...

If I can keep the baffle width to 24 inches I can more easily try it out
in the corners...with legs to "open" the bottom so the driver "thinks"
is sees a continuous baffle and perhaps a wave guide on the bottom
as you originally suggested to direct the lower frequencies into the room...

What do you think JLM...can a 24 inches width work in this application?

Warm regards -Richard-

[ooheadsoo]

The triangular ceiling corner mounted baffle would have to be fairly large for the B200 if you're thinking about using it as an infinite baffle. Rule of thumb is to provide 4 to 10 times the Vas, which for the B200 is 107 liters or about 1.3 cubic feet. So the baffle would have to be at least 4 feet across. Having the drivers mounted about 6 feet above the floor and angled down may not provide a natural presentation. That brings you back to the wall/wall corner mounted baffle (open at both ends) that I proposed a few pages back.

I don't really intend a full infinite baffle with an enclosure.  I still intend the radiation to be essentially dipole - stuffed in the corner.  Basically, the back wave will be quashed.  However, the proximity of the corner walls should boost the bass similar to an infinite baffle, shouldn't it?  The problem is the image depth, like you mentioned before.  Will EQ really solve that?  

I'm not sure having the speakers mounted in the corner is a big problem in the presentation - at least for me.  I almost never just sit there looking straight ahead at nothing while listening to music.  There's just no time for that.  I have too much music I need to listen to either for school or while I'm busy doing something else.  I have no desire to be locked into one position.  Interestingly enough, my ears are also more sensitive to high frequencies from above than straight ahead or below.  This could prove interesting - or aggravating.  In any case, I will still be using my mbow1 at my desk for when I need something in my face, maybe at lower levels.  This is basically an experiment for me just to play around with an old concept that I have no experience with.  I'm not going to spend much on the baffle and the drivers are reusable.  It would be nice to hear someone else's implementation, however.

[nodiak]

Hi Richard, Nigel (barfind) said 24" works for him, so sounds like that shouldn't be a problem, maybe he'll check in soon. You could always add 3" or 4" sides to end up with wider, can just use cardboard to see if wings would help before cutting more wood. These sides don't even need to be full length ( to the floor), just halfway down should work if the driver is mounted at 30-36", imo. I'm using 3.5" sides with a 10" wide front for my OB's to keep them narrower, (they only need to go to ~ 125 hz). Another set I have has wings/sides at aprox. 30 degrees. I like the look, comes off a little more furniture like, blends in a little better imo (gotta live with em). Also these wings allow the OB to stand up easier, I use a short 2" x 8" piece going out from the back as a kickstand. Your room is pretty big, will be interesting how much bass gain it will add. Good luck.
Out of interest I wonder if you've seen the Cult of the Infinite Baffle? As to your question of baffle size IB is the extreme to make sure no long waves can cancel out, also no backwave for tighter bass. I hope to do IB, might be moving soon so am holding off. http://f20.parsimony.net/forum36475/
I'm glad folks are moving ahead with the various OB's in various rooms. Will be fun to hear results, and discussions of the trial and error process. Don

[-Richard-]

Hi Don,

I deeply appreciate your help and carefully described information...very
interesting and exactly what I needed to proceed...I like the idea of wings
down the road...I can see how they might soften the look and provide a much
needed stability as well...and Deb would appreciate the ability to fold them
back when not in use...Nice!!!!

And thanks, Don, for the link...great fun and an education in the DIY underworld.

When Deb saw Mark's pictures of his first foray into a baffle design for the B200's
her heart sank...she looked at me with that..."these will overpower our house"...look...
and I thought...hummmmm!!!!!...thinner with wings...yes...I don't want to alienate Deb...
she is such a good sport about my immersion in this mad desire for...for what?
God only knows...the hunter hunting for the thrill of the hunt...

Exciting to be a part of this exploration...thanks to Dan's generosity in sharing his
own excitement and investigative journey into alternative modalities...

The Dark Star Confederation is growing in size...now AC...later the world!!!!
Only kidding.

Warm regards -Richard-

[Dmason]

Richard

Folding baffles can be quite elaborate and even tasteful in the vein of a drop leaf table, or a piano case vis a vis furniture.

I have built a pair of DarkStars with a narrow static baffle which mounts the driver, and two wings of different widths to maintain the offset of the driver. The outer verticals have been rounded over, and the whole thing has a very smooth looking mahogany stain cherry veneer, also on the edges. The wings can be folded back when not in use and wind up looking for all the world like a pair of floorstanding speakers. Here, piano hinge is your best friend, and it adds a continuum to the baffle, as a whole. This works incredibly well, and any talk of the moveable wings vibrating is from people who havent ever tried this stuff. Using 3/4" MDF which is cut to run below the pile of the carpet, yes, sorry, but it works incredibly well. And, this way one can use wider baffles, as space allows. Not listening, fold them back.

 These particular specimens also have a triangular "kickstand" support, and through a cutout, will be mounted a very nice 12" pro audio woofer with a Q=.53 and there is your dipole bass, with a response to about 45Hz. Very simple, and extremely effective!! These modern marvels are going to be going into the home of a colleague of mine. He loves the sound of a full range DarkStar rig.  

[barfind]

Richard, 24" wide are what my OB's are now. I will be redesigning them (version 4) and going to 14" with wings x 48" high. 24x36 works great for me, BUT!, dont forget I augment the bass with a SUB to 80hz. The B200 does make good bass in this baffle (its running fullrange), but I like deep powerful bass as well as the rest the B200 does so well.
BTW if you lift them off the floor the bass will imeaditly start to roll off sooner, the higher the baffle the higher the rolloff. Sorry, this seems to be the part of phyisics we cant bend.

Nigel

[-Richard-]

Thanks Dan and thanks Nigel,

Yes...of course...I can easily see that wings will get us closer to the ideal
baffle size without the inconvenience and cumbersome scale of the single
continuous panel of wood...very clever and very useful and very aesthetically
versatile...a perfect solution...

Thanks Dan for the confirmation of piano hinges...that is what I imagined would
be the least likely hinge to ring from driver resonances...and give the most integrity
and stability to the wings...especially if one is opening and closing the baffle everyday
over a long period of time...

Thanks Nigel for the description of how height defeats the baffles ability to maintain
bass response...very convincing...and clear to understand...

Thanks Dan for the thorough overview of how to approach the "build" of the baffle
and a clear "picture" of what a finished unit could look like and how it could function...

It seems as if we are getting very close to a functioning model that could work in a
number of different room configurations...and seeing the limits as well as the strengths
of the B200 using a few different design strategies...

I am going ahead with a simple plywood panel 25.5" wide by 42" high using a 10%
off center placement of the driver in mirror image just to burn it in...after a few weeks
of that I will begin to design an OB wing baffle...

One thing that is interesting here is that if one tries to maintain the 10% off center
placement of the driver with an equal distance from the top to the side...with wings
of different widths...it is really impossible to actually be faithful to that proportion...

The wings move the driver further away from the "inside" (closest side) edges than
the measurement to the height of the top of the baffle...

Only if the driver could move downward as the wings were opened up could that
center of driver to the top and edge of the baffle be maintained....a very impractical
and challenging mechanical action that would place the driver in an unstable
environment...so as the wings are opened out to a flat position the driver would be
closer to the top then the closest edge...and I assume that in that case the perfect
relationship of the driver becomes less important then having the extra baffle area
to reinforce the bass...

Any insights along these lines would be deeply appreciated....

Perhaps, Dan, at some point we can discuss some alternative woofer drivers
that match well with the B200...although I realize that you are not advocating in
strictly absolute terms the use of a subwoofer in all situations...and of course
assuming that would not impinge on your speaker designing and building
proprietary information...which  I deeply respect and wish to honor...

Thanks Dan and Nigal for your invaluable help and careful descriptions.

The Dark Star Confederation has moved a giant step closer to full lift off...

Warm regards -Richard-

[mcgsxr]

Richard - sorry for disturbing your wife...    she can call mine up and they can commiserate!  Michelle's only comment was "you're fine", which in the context of all our friends translates directly to "you are in definite need of diagnosis"....

Ahem.  

In the case of seeking to hinge open baffles such as my own, and preserve some sense of normalcy when not in use, a simple L could work.  I measure 12 inches to the start of the driver from the inside edge of the baffle, plus 9 inches to get past the driver, and then one could insert the piano hinge, for the remaining 15 inches of width.  This would drastically shave down the width of the baffle to a more acceptable 21 inches, when not in use, and you could vary how far from L to --- you place the baffle, to taste for both looks, and sound, AND preserve the 10% offset of the driver.

Would also save on piano hinge, which I assume is not cheap.

Just a thought, and some indication that I CAN conceive of a more socially acceptable solution, for those not blessed with a basement, and the ability to have some fun with gargantuan panels of raw mdf...

My final implementation will be from the "chi chi" russian birch, and will doubtlessly involve many things gleaned from the experiences of my fellow explorers here!

I look forward to reading about your experiences, and down the road (the basement will be finished eventually, Daddy needs a pool table!) I too will have some social constraint on my designs, so please share!

[barfind]

Richard, you know a Carefully!!! setup sub does nothing execpt add to the music experience. I was running 2x 12" woofers on the same baffle as the B200. This worked well until the B200 started makeing its own bass, and then the bass overpowered the soundstage and detail. Its taken me several months of building and several weeks of positioning the sub, but now I don't ever notice the sub .
 What I am saying here, and this is only for the non purist among us, the B200 is a fantasic driver. I have used and still have 3 other fullrange drivers, but none come close to the B200. There is nothing wrong with extending the range of your system with the addition of a sub. You could make a beautiful speaker with managable dimensions, and still have real HI-END sound in your own room.

[Dmason]

I agree with Nigel, the one and true way to hear all in proper context is with a good fundamental underpinning the music, something for the wide range driver to sing over.

I have noticed some people using dipole bass drivers, such as this outfit I am working on, but they might also add in a real subwoofer to take care of <45Hz, which would be necessary to make it a full range system. When I added my sub to the dipole bass, the context of the system was then fully fleshed out.

Nigel Barfind is right; The B200 takes some time to really break in and then they start making Real Bass on their own. I have found two things here: using digital EQ, and digital amplification, digital amps, in this case the RealiT, exert far more driver control than tube or angle grinder amps which means better performance from openly baffled drivers. Digital EQ means you can bend the mechanical characteristics of the driver to your liking, including extracting A LOT more bass out of, and of course contouring the rest of the bandwidth to counter impedance and frequency response issues.

Using digital amps and contouring makes for an easier implementation of full range with bass speakers, increases performance levels. Using Red Wine amps seems to make them sound closer to tube amps.

Mark

I agree with the L config for a basement, but for a livingroom the two wings avec veneer is the way to go, so you are never viewing the rear of the baffle at any time and get good wood from any viewpoint in the room. It really looks nice, and in rooms with lower lighting, the darkening cherry looks austere and very classy, with the "dark star" of a driver showing up, but not calling attention to itself. In other words, open baffles, dolled up right, absolutely can pass the gracious living room test.

[-Richard-]

Hi Mark,

I read aloud Michelle's response to your first baffle design to Deb and she
laughed as loudly as I did...very nice of you to share that...great fun!!!

"...I too will have some social constraint on my designs..." nicely put and an
interesting consideration that is part of our challenge to solve the design
of the baffle elegantly...for Deb who is a professional designer, "aesthetics
are everything," and that is how she organizes her world...but certainly for
most ladies, aesthetics make them feel that a sense of order is present that
makes life less agitating...and the "constraint" to find effective solutions that
also look pleasing will only lead to a more satisfying innovation...

Your L shape design solution for the baffle is intriguing and intelligent and
minimal which is always a good goal in design and does seem to solve the
the problem of keeping the driver in an ideal relationship to the top and inside edge...
besides using the baffle as a flat panel...if you were to use the folding "side" panel
in a perpendicular or L configuration, I wonder what effect that would have on the
sound, seeing that you could not maintain a similar continuity with both sides...

Hi Nigel...yes...I see your point about introducing a woofer into the equation
with the B200 in order to help create a more fleshed out foundation for the music...
and your experiences suggest that you have approached the integration of the
sub with the baffle very carefully over a considerable period of time before everything
settled down nicely...perhaps, Nigel, you could share with us some thoughts
about which subwoofer design works for the B200 in your room...and some of your
experiences in working out that very sensitive integration issue...

I realize that by using a subwoofer with the B200...or any wide range driver...it can
relieve the driver from having to "drag" the mid range into the lower frequencies
which could compromise its mid-range magic...

Right now the use of a subwoofer feels a bit daunting to me...I am afraid of
what it could do in this mobile home in the way of unwanted resonances...these
mobile’s are not built for the ages and put together without an eye/ear for sound
transmission...

Thanks for your help Mark and Nigel...revealing and instructive and moves the
Dark Star Confederation closer to the Nirvana Galaxy...

Warm regards -Richard-

[nodiak]

Hi Richard, a thought to remedy the set distance of driver to top...make a small hinged wing on the back, above the driver, that can be opened up to give a greater distance to the edge from that direction. Don

[nodiak]

Also, some shorter OB's. Wider too, but I bet could be narrowed to 24" with those sides.
http://members.myactv.net/~je2a3/open.htm
check out the "visitors open baffle" link for good photos.
The lower, tilted driver mounting is different, with the music coming up and filling the room, like an ampitheatre. I like it, and I like the benefit of not having the cabinets in the sightline, (tho that's how we've come to identify with speakers). I didn't feel as tho I was missing any music because of less direct intensity, I liked the less in your face delivery, ymmv. Remember when it was common to have short speakers on the floor? I think things have gotten too sensually intense in audio (no duh   ), and I like OB's and lower, less visual drivers. Working on hiding the sub too   .
Shorter OB's might be a consideration for "social considerations".  
Don

[miklorsmith]

Richard is clearly wanting to lift this Confederation ship off the ground.  The old girl doesn't seem to have the juice though.  Three tries on the starter, a sputtering EdgeDrive, and looks like we're stuck in this swamp for at least four days waiting for parts.  Not that I expected anything else.  Look at this dripping hell-hole.  I'm surprised there's even anything to eat but eel or slug.  At least we're here together, eh?

After the last debacle, you'd think those schmucks would have gotten it right.  I miss the days when you could still roll up the sleeves and work on your own 'cruiser.  With all the newfangled VirutalPlasma goodies, that just doesn't work.  Plus, these guys don't know what they're doing half the time.  No way to tell until you're broken down on some bass-ackwards planet.  Good luck finding any worthwhile help there (here).

Sabotage?  Can we trust these "mechanics"?  No choice, we'll miss the rendezvous if we wait for reliable help and parts.

Just relax, I guess.  I'm gonna just prop my feet up on this giant mushroom and watch the moons rise.

Good luck, warriors of the open baffle.  Rag-tag band?  Not!  Your resourcefulness and determination will persevere.  May the sonicbliss be with you.

Sudan out.

[Dmason]

Mike, are you really Douglas Adams?

Open Baffle Construction Manual

1- Cut MDF panel
2- Cut hole
3- Screw in driver
4- Hook up speaker cables
5- Play Music

Getting too complicated. Only the driver is German engineered. The rest is simplicity itself. Mark McG is already hooked on the concept, the driver, the sound. Friend coming tonight not to visit, but to LISTEN.

[-Richard-]

Hi Don,

Nice solution!!! Quad dimensions, aimed up and sitting below eye level ...
so it is no longer in your face...I like the look of it...this is definitely worth
experimenting with at some point...and the pictures are clear and sharp...

I received my Omega 8's before the stands arrived so I had them on the floor
for a few days and they actually sounded great in my room...they loaded
the room perfectly...the designer of Skylan stands, our friend Noel from
Canada, feels that speakers are generally placed entirely too high and
has proven this to a number of speaker manufactures at CES shows...
however as you pointed out visual habits die slowly...

Nice thinking...innovative and in this case the result of a glance backward
to a classic design of early audio...just like the wide range drivers themselves
which are based on very early models...rediscovering the classic designs
of the past that worked but got lost in the rush toward modernity is exciting
and makes us appreciate the genius and creativity of earlier generations...

Hi miklorsmith,

Yes...I know what things are like on that planet...outside of the Confederations
jurisdiction...waiting forever to get things done...accident in the time machine
apparatus...running backward...watch for the growth of reptilians...the conifers
disappear also...no more apples...seas begin to boil...air turns acrid...
better pull out your space craft manual and begin to DIY...times running out...
oh yes...the brain grows smaller...nasty business that...

Warm regards -Richard-

[powerbench]

Placed on the narrow end at 12 ft ,listening posion  8-10 ft from speaker what is  the minium size baffle,do they have to go in corners,all driven with the ClariT...any takers??

[ooheadsoo]

I also think that having speakers placed too high is a bit of a pain, and standing in front of my mbow1 does create a deeper soundstage due to the treble roll off.  I'm hoping that with the corner mount, being off axis will help out here.

Does any one have a take on just how sealed off the corner mounted dipole should be?  Just loosely placed into the corner or with the edges mounted very close to the corner walls, say less than 1/4" gap?  Since I don't actually want to simulate the sealed cavity of an infinite baffle, maybe it would be better for the corner mount to be only loosely placed into the corner with, say a 1" gap.

[mcgsxr]

Dan is right, I am hooked on this sound... and I LIKE building speakers!Since I have hooked up the little JVC, I have been entirely unmotivated (in a good way for once!) to play around at all with this setup.  I have been coming home, and as soon as husband/fatherly duties are completed, I retreat to the basement bunker to drop cd after cd into this combo.

Powerbench - you mentioned "5 Days in July" in your thread about your Mini-Me's - when you get here, you will have to compare and contrast your experience with what you hear in my room.  As for your question about baffle size, I implore you to visit this link, and download the xls sheet - use it JUST to give you a sense of what is possible, I would not get TOO wrapped up in modeling differing shapes etc.  You will find the sweet spot for your ears.  I noticed that for my xls experimentation, the response curve of the 36, 30 and 24 were identical, just less gain each time.  The 48 width had a better look to the response curve, but even for me, alone in the basement, that is a WALL of mdf, and I was afraid it was too wide to allow enough of the dipole sound to get back past them.  I went with the 36 as a starting point, and it turns out to be the ending point for me too.

http://www.t-linespeakers.org/downloads.html

Richard - glad I could raise a few laughs for you and yours, I do try to keep it light, and with the written word, it is often hard to convey exact meaning - looks like success here!

Thanks to all for their thoughts, this is a fun thread to come home to!