Gravity Well Of A DarkStar

Dmason · « **Reply #60 on:** 31 May 2005, 07:46 pm »

Gary,

Neat ideas, but this I think would be a test baffle of sorts, but is close to the final one used by one other who has been playing with the B200 for several months.

The 3/4 ply would be plenty stiff, methinks, and IMO, of greater importance here is the opportunity to do a CheAp aNd DiRty mass loading of the driver using it as the pivot between the baffle [weight] and a dowel to prop up the baffle. I did this in the beginning, and was amazed at the effect it had, not subtle either. In tweaking the magnets for aerodynamics, I just worked up a deal where I could use the dowel, I think I used duct tape to be honest, and in some ways it was actually preferable to the baffle-mount/lexan baffle specimens I have at home. This means that potentially, in mounting and support, Less = More.

Imagine my surprise! Plus, with the simple dowel, you can adjust the tilt of the baffle to your heart's content, making the whole affair easily adjustable in both horizontal and vertical planes.

I think my wood baffle examples, at least to me, sounded better than my Lexan baffles. The Lexan ones look highly cool in the corners, and might be better with modular bipole bass augmentation situated in the middle, between the speakers, but separate bass augmentors can "hide" very effectively behind wooden baffles, and dipole bass augmentation can pretty much go anywhere, it seems, based on experimentation by measuring, cutting, glueing, wiring, damping, adjusting, listening, etc.

IKEA -- Your Open Baffle/Dipole SuperStore

mcgsxr · « **Reply #61 on:** 1 Jun 2005, 12:02 am »

I am pleased to announce the arrival of a pair of drivers on my doorstep! Now, if only my local HD had 3/4 Russian Birch ply in 4x8 sheets in stock... wankers had only 2x4 sheets. Not sure how to proceed, but I will start by calling all the HD in a given radius of my house... tomorrow!

let the games begin!

Now, to locate a circle cutting jig, for accurate holes, and rebates. Lee Valley, here i come!

Dmason · « **Reply #62 on:** 1 Jun 2005, 12:11 am »

Mark

Congrats on your Gravity Generators.

You don't "need" a Circle Jig IF you are handy. You need a compass and be able to describe a circle from an accurate point using a set square. You need a good protractor to practice you Gr 10 Geometry. Use the driver flange if you need to, this is not Science, this is Fun.

No big plywood. Cheeky bastards. Use some nice 1" MDF, but mount the driver on the front, and get out a rasp and do some back cutting ~45' -1/2" it'll make a difference, I am sure. Get the inserts too. Big diff.

mcgsxr · « **Reply #63 on:** 1 Jun 2005, 12:25 am »

Big IF there Dan... I want to do this right, and I want the capability of doing all subsequent drivers right too, so I will buy the circle jig - I bought the router for a reason, and I am a bit of a tool guy, so it fits my approach. The KIT41 deserves better than I gave it, so for all speakers going forward, I will take the extra time to do it right.

Here are some quick pics - the high rez stuff on the Visaton website does not do these justice - they really do look military spec in real person.

Dmason · « **Reply #64 on:** 1 Jun 2005, 12:42 am »

Sweet! Ain't they friggin' monkeys??

And now for the cool part: I had some communication with Visaton's design staff months ago, and in asking what the hell the cone was made of, they said, "manilla." What they refer to as Manilla in Europe, we in North America know as "hemp."

I thought I would save that for now!! It sort of explains the other worldly midband sound in these Mil-Spec Monsters.

-Richard- · « **Reply #65 on:** 1 Jun 2005, 04:49 am »

Ahhh...Dan...you are proving to have a genius for drama
and timing...bravo!!!!

Nice revelation...like a bolt of lightning!!!

Warm regards -Richard-

mcgsxr · « **Reply #66 on:** 2 Jun 2005, 11:04 am »

Quick update - I have purchased some 3/4 mdf, and had it ripped into 3x4 foot sheets. I have tomorrow off, so I will be tackling the "build" then.

I will simply cut the through hole, mount the driver, and some binding posts - I would skip the binding posts, but my speaker cables terminate in Eichmann Bayonets, so I cannot simply attach them directly to the driver, even for the test mules. I plan to do a rebate (flush mount, not $$ back!) for the driver longer term, but am uncertain what the final shape of the baffle will be etc.

You may have noticed that I mentioned Baltic Birch as my planned baffle, and longer term I still do. I simply want to experiment with $33 worth of material, rather than $140! Once I get the mdf panels in the configuration that does it for me, I will use them as the templates for the pricier material.

I look forward to putting the power tools away, and sitting down in the listening chair. As the drivers I bought are used, I should be able to give some feedback reasonably quickly.

JoshK · « **Reply #67 on:** 2 Jun 2005, 01:38 pm »

Or you can do a constrained layer by gluing a piece of thinner BB to the MDF, or better yet two really thin pieces on either side of the MDF. Just a thought.

brj · « **Reply #68 on:** 2 Jun 2005, 04:17 pm »

Quote from: JoshK

Or you can do a constrained layer by gluing a piece of thinner BB to the MDF, or better yet two really thin pieces on either side of the MDF. Just a thought.

I haven't really looked into constrained layer damping yet, but isn't the concept to have some "give" between the different layers? You want a visco-elastic layers sandwiched between constraining layers, right? Presumably the glue acts as a visco-elastic layer while the MDF and plywood act as a constraining layers. I guess I didn't figure that when typcial glues dried, they exhibited much "give". Is there a particular type of glue that works well in this capacity?

Even with a suitable glue, wouldn't the driver mounting screws - presumably driven through all layers - serve to effectively bind the layers together and eliminate the intended benefit?

Thanks!

JoshK · « **Reply #69 on:** 2 Jun 2005, 04:40 pm »

Ok, I was being vague and inprecise. Sorry. yeah I think your right, that you need a elastic layer for constrained layer. You could do that too, or you can just make a "composite" layered baffle. Not sure if that would help or not.

barfind · « **Reply #70 on:** 3 Jun 2005, 06:51 am »

What about 1/2 birch ply -1/4 cork- 3/4 mdf. This is easy to do useing sprayable contact to glue them together. I was thinking too, if a 6mm (1/4) layer of cork on the front of the baffle to tame reflections, you dont need to rebate the driver into the baffle. The driver rebate is 6mm, which means you can just cut a hole to mount the driver and cut the cork in around the driver and the driver will end up flush

Nigel

nodiak · « **Reply #71 on:** 3 Jun 2005, 03:45 pm »

Nigel, good to hear you pitch in over here. I'm going for the Red Wine Teac, maybe the Monica Dac too. Always been interested in the B200's, I bet they would match the tripaths well. Don't you have a Sonic Impact? How does the B200 sound with it? (Sorry if I missed a post on this.) Don

mcgsxr · « **Reply #72 on:** 3 Jun 2005, 06:15 pm »

The panels are cut, the edges rounded over, the through holes cut, the holes for the bolts drilled (I have decided to use actual allen head bolts to attach the driver, since I can get a wrench at them anytime I want, and I believe this will be a tighter connection than just a screw) everything is sanded.... I am waiting for the glue to dry on the small panels I built to hold the binding posts...

Pacing, and waiting...

barfind · « **Reply #73 on:** 3 Jun 2005, 09:28 pm »

Quote from: nodiak

Nigel, good to hear you pitch in over here. I'm going for the Red Wine Teac, maybe the Monica Dac too. Always been interested in the B200's, I bet they would match the tripaths well. Don't you have a Sonic Impact? How does the B200 sound with it? (Sorry if I missed a post on this.) Don

Hi Don, Yes I have 2 SI amps, but I haven't tried them. They are just sitting waitng until I have built my new house. I plan to semi-retire then and will need items to tinker with, thus the wait. I can heartily recomend the B200. Mine have about 120hrs on them and they are just marvelouse. Acually the smoothest speaker I have had.

Nigel

Dmason · « **Reply #74 on:** 3 Jun 2005, 09:42 pm »

hi Nigel

I saw your thread on DecWorld, awhile ago. My experience mirrors your own. These are about as good as wide range drivers get, and totally KILL the $$$ Fostex, and sound better than the Hartleys to me.

I find that they actually really need to get worked in. Two pairs, one in the burner box for about a week of transient heavy stuff to REALLY loosen them up, because they are soooo high SPL that otherwise they might never break in!! Now they are and they lose some of the topped up highs.

I decided to start that thread because I had realized I could get some interest in these projects and not give away all my secrets were I to build a few. (Orders for FOUR, from friends and colleagues) who love the full range version, on either Acrylan or veneered wood baffles, with either bass pipes, or small sealed subs. Contrary to popular belief, sealed subs work fine. Thanks for weighing in, had hoped to hear from you and please share your thoughts, there is a large audience for this stuff, and the B200 is killy with hotrod Tripath stuff. ta ta,,,Dan

barfind · « **Reply #75 on:** 3 Jun 2005, 10:15 pm »

They are GOOOOOOOD aren't they Dan. Hey do you have any pics?

Nigel

Dmason · « **Reply #76 on:** 3 Jun 2005, 10:36 pm »

I don't have a digicam, and get info-overwhelmed-o-loaded each time I go to look at some. I do have a good camera, but currently it is at the bottom of the Pacific, about 40 nautical miles SSE of the Cortes Bank, and I can't get to it that easily.

I will say this though, I have done a shitload of listening to wide range drivers over the last few years, built various loads, and the B200 is the bullseye, for my ears. I don't know about other's impressions, but with Vinnie's amp gripping it, it is capable of unbelievable dynamic snap and tension with the right stuff. I mean, real crunch!!

Listening to really well produced stuff like Yellowjackets, who needs horns?Others are going to be chiming in, like, totally soon, dude. (Dogtownspeak)

Now, if someone can come up with a good phaseplug, we have the unstoppable wide range driver, which needs no tweeter, and does REAL bass.

barfind · « **Reply #77 on:** 3 Jun 2005, 11:23 pm »

Dan Planet10 makes phase plugs for varios drivers, and he had B200 for a time. He said they were the best driver he has heard. Anyway I will find his info and post it. Maybe if a few of us hassle him he might develop plugs for the B200.

Nigel

barfind · « **Reply #78 on:** 3 Jun 2005, 11:29 pm »

Have a look here
http://www.planet10-hifi.com/index.html

Nigel

Dmason · « **Reply #79 on:** 3 Jun 2005, 11:38 pm »

Mxgsr owns Planet 10's Visatons now. Dave D definitely loves the Visatons, and he has heard everything. That was one opinion I long ago took very seriously.

I have noticed that the phaseplugs on the big Field Coil Supravoxes are simple cylindrical shapes, and have twice read that the phaseplug itself is more important than the contour.

Edit: The 1" generic Planet 10 one looks like the goods. Maybe I should sell scalpel kits to cut the dust cap off. The manila they use looks tuff-as-hell.