Something New Cooking...............................

[---k---]

Great work so far Dan. Looking forward to seeing where this goes. :T

[dlneubec]

i wanted to do this design a number of years ago, but didn't have the ability to turn the diffuser/horns and had no idea, still don't, how it could be modelled in a software to predict its response. Even if you assume you can look at it in cross section and use that to model the horn, I didn't know a way of doing a curved horn that expancds as it curves, with one side shorter than the other and with a dome tweeter. Probably guys more familiar with horn response could do it easily.

A year or so ago it occured to me that I could stack a couple of the dayton waveguides using the outside of one as the diffuser and the inside othe other as the waveguide. A couple folks told me they didin't think that the profile would be right, but for $13 each, I picked up 4 to play with and here we are. A couple other project proceeded top jump in line since then. The concept does seem to be working very well. The only problem area is in the 12khz and up area and so far it is not standing out as lacking, though my ears are 56 now, so other might be able to notice it. I think maybe a little more work on a specially designed face plate/throat opening for the tweeter might even improve 12khz and up response a bit. I'll try and fine tune that later, assumning the actual build moves forward.

With what I've heard from one speaker so far, I think this is going to turn out quite well and I could see it easily replicated with a smaller woofer using the 8" or 10" PE waveguides and less expensive drivers. I did some early measurements with the Dayton RS28F and it looked good also. The Usher 9950 looked decent as well. Both of these were without really optimizing the throat size for the particular tweeter.

What John said is what I'm hearing. A vocalilist, for example, seems more "in the room" with you than any other speaker I can recall listening to, at least from a single speaker, and it us a very enticing sound. We'll see how a pair works.

I'm still working on the overal design look I want. I'll probably post a mockup here before too long.

[dlneubec]

Here is a conceptual of what I initially have in mind, though it could change.

[Hdale85]

Almost looks like Asian architecture.

[dlneubec]

My wife says the same thing. It's the pagoda look on top, for one thing. I may have to come up with an asian name!

[JonMarsh]

Here is a conceptual of what I initially have in mind, though it could change.

Looks pretty interesting- how stiff/steady do you think the deflector/waveguide assembly will be if the woofer is cranked up a bit?

[Hank]

Name suggestion: "Serenity"
If you made the upper MDF rings larger in diameter you could get rid of the nylon standoffs, their bolts and the aluminum brackets. Your long support rods, if they had threaded ends, could be screwed into threaded inserts in the top of the base unit. Just thinking that would perhaps result in more rigidity. Maybe a skosh larger diameter rods also?
Looking great!

[dlneubec]

Looks pretty interesting- how stiff/steady do you think the deflector/waveguide assembly will be if the woofer is cranked up a bit?

It might depend on how much mass is added as I treat the waveguide/diffusers to ensure they don't resonate on their own. I'm leaning towards filling the bottom two diffusers solid. The top diffuser is probably going to be doubled up so I can fill the space between two of them stacked. I don't yet know what material to use for the fill, so any ideas are welcome.

As far as the supports go, I'll have to try all 4 of them to see how it feels. It may need something more solid. The prototype does not really seem to suffer and it is just sitting with the threaded rods warped a bit to fit into 4 of the woofer openings.

Name suggestion: "Serenity"
If you made the upper MDF rings larger in diameter you could get rid of the nylon standoffs, their bolts and the aluminum brackets. Your long support rods, if they had threaded ends, could be screwed into threaded inserts in the top of the base unit. Just thinking that would perhaps result in more rigidity. Maybe a skosh larger diameter rods also?
Looking great!

Cool name, thanks!

I have thought about making the rings larger and will definitely test it out. One concern is what happens to the response if the expanding curve of the waveguide/diffuser combo stops expanding and has a section with parallel sides. Some measurements should tell the story. My original intent was to thread the uprights into inserts just as you describe.

If I keep the current mounting system, I do plan to use larger uprights than those pictured. These just happend to be the ones I had at hand that fit without cutting them down. Larger dia. uprights will naturally increase rigidity and would look a little more balanced.

[Paul W]

It might depend on how much mass is added as I treat the waveguide/diffusers to ensure they don't resonate on their own. I'm leaning towards filling the bottom two diffusers solid. The top diffuser is probably going to be doubled up so I can fill the space between two of them stacked. I don't yet know what material to use for the fill, so any ideas are welcome.

I've used polyester resin cut with sand to fill spaces like that or, for lower mass, pour foams are available in many different densities. Just be sure to rough up the surface in case you pick something that doesn't naturally adhere.

[dlneubec]

Paul,

Where can you get the poured foams at?

[dlneubec]

Bummer! :cry:

I was ready to order more of the 12" wavguides for the second prototype speaker and they are out of stock at PE, showing not due in until December 11.

Looks like I'm going to have to formulate a plan B.

[technodanvan]

Bummer indeed! There may be someone on one of these forums that could have a few extras, waiting that long could really put a damper on the project.

For supporting the rings and waveguides could you use a single, heavy vertical support on the back side of the speaker? It could angle up slightly with the waveguides and be used to hide all the wiring as well. Understandably this may affect frequency response slightly, but if it's on the back (and sufficiently narrow in width) I can't imagine it would be significant.

Depending on the finish it may almost make the waveguides appear to hover. Just a thought.

[Paul W]

http://www.aeromarineproducts.com/

When I was pouring large WGs a while back, aeromarine had the best prices, good products & quick service. I'm a plastics newbie & John Greer answered all my application questions personally.

[dlneubec]

Bummer indeed! There may be someone on one of these forums that could have a few extras, waiting that long could really put a damper on the project.

For supporting the rings and waveguides could you use a single, heavy vertical support on the back side of the speaker? It could angle up slightly with the waveguides and be used to hide all the wiring as well. Understandably this may affect frequency response slightly, but if it's on the back (and sufficiently narrow in width) I can't imagine it would be significant.

Depending on the finish it may almost make the waveguides appear to hover. Just a thought.

Yes, that is an option that would also work. I may play around with that as well. I essentially did that here :T :

[dlneubec]

http://www.aeromarineproducts.com/

When I was pouring large WGs a while back, aeromarine had the best prices, good products & quick service. I'm a plastics newbie & John Greer answered all my application questions personally.

Thanks, Paul. Looks very interesting!

[AdelaaR]

For supporting the rings and waveguides could you use a single, heavy vertical support on the back side of the speaker? It could angle up slightly with the waveguides and be used to hide all the wiring as well.

I think that's a VERY good idea!

[gbegland]

I think that's a VERY good idea!

Not that you're counting, but I vote for single spine as well. Maybe get some of the 4" square, aluminum T-slot tubing from 80/20 or Faztek and then the height could be infinitely adjustable too. If the 4" looks too chunky for you, they've got 4" * 2" that's super rigid too. Especially if you get the thick walled stuff.

Greg

[CraigJ]

Bummer! :cry:

I was ready to order more of the 12" wavguides for the second prototype speaker and they are out of stock at PE, showing not due in until December 11.

Looks like I'm going to have to formulate a plan B.

Regarding plan B, I wonder if Dave Pellegrene could whip up a few up for you? Perhaps even use your current diffuser as a guide....

I'm looking forward to seeing how you think this project compares to your Contrappeso Project.

CraigJ

[dlneubec]

Craig,

I have discussed it with Dave back when I started on it and his is willing to try it, so that is one route I can look into.

I talked with another guy a year or so ago, when I was first thinking about picking up this design concept again, who has the capability to turn the guides out of wood, which also remains an option for a finished product.

[dlneubec]

The single rear spine idea is worth considering, but in sketching ideas so far, I haven't found anything I like the look of and/or a method to connect the omni horn solidly enough from one point.

I've used the 80/20 extruded T-slot before and it is cool stuff. I even have a piece of the 1515 from an old project. An acceptable, rigid conneciton between the edge of the omni horn (3/4" mdf) and the T-slot is not obvious at this point.

[gbegland]

The single rear spine idea is worth considering, but in sketching ideas so far, I haven't found anything I like the look of and/or a method to connect the omni horn solidly enough from one point.

I've used the 80/20 extruded T-slot before and it is cool stuff. I even have a piece of the 1515 from an old project. An acceptable, rigid conneciton between the edge of the omni horn (3/4" mdf) and the T-slot is not obvious at this point.

What if you do not mount it from the side of the MDF? How bout a top mount? Like claw dropping down. It could hold on around the tweeter in some fashion.

[dlneubec]

That would be interesting and unique!

[gbegland]

That would be interesting and unique!

How much do you think the top assembly weighs?

They have rounded profiles of the T-slot too, so it might fit better with the round waveguide top. And there are the profiles with only one side with slots, so it looks clean the rest of the way around. Maybe anodized black.

[dlneubec]

How much the top assmbly weighs is pretty dependent on what material I use to deaden the waveguide/diffusers. I'll have to see what it weighs now with tweeter and guess at how much additional damping might add.

[technodanvan]

I know the material will be chosen based on the design, but wouldn't t-slot 'ring' in this situation unless coated with something?

[gbegland]

I know the material will be chosen based on the design, but wouldn't t-slot 'ring' in this situation unless coated with something?

I used the heavy guage myself and the walls of the tubing are thick enough to be very dead. Not ringing at all. Of course it is hollow so chould always sbe filled with something too.

[Face]

I have either a pair of 10" or 12" Dayton waveguides hidden in my stash. Are you set on the "spine"? If not, I'll see what I have.

[dlneubec]

I find the spine concept interesting, but I'm not seeing it fitting together with this design at this point. My SoundRounds (pictured above) were designed from the ground up to incorporate the spine. In this case, it feels like an add on.

Also, there is really not any benefit to being able to adjust the height of the omni horn elements, since an optimum position can be found for the particular drivers, waveguides and diffusers used and at that point I can't see any reason to adjust them further.

Face, If you are interested in parting with a pair of the 12" Daytons, if that is what you have, please let me know. I'm definitely interested. :T I need a pair to complete my second protoype.

[cjd]

Suspending the upper levels from some type of minimal "cage" strikes me as an option. I may have to sketch it to prove myself wrong.

[gbegland]

Hey Dan, I think your project will not be complete unless you work these into the design:

http://www.ebay.com/itm/Bespoke-Solitaire-Omni-Directional-Ribbon-Super-Tweeters-Speaker-Upgrade-Pr-/321005358469?pt=UK_AudioVideoElectronics_HomeAudio HiFi_HiFiSpeakers&hash=item4abd690d85

:jawdrop:

Maybe these will be better than Jon's Diamond tweeters!

Greg

[JonMarsh]

Hey Dan, I think your project will not be complete unless you work these into the design:

http://www.ebay.com/itm/Bespoke-Solitaire-Omni-Directional-Ribbon-Super-Tweeters-Speaker-Upgrade-Pr-/321005358469?pt=UK_AudioVideoElectronics_HomeAudio HiFi_HiFiSpeakers&hash=item4abd690d85

:jawdrop:

Maybe these will be better than Jon's Diamond tweeters!

Greg

Aw, Geez, that is so wrong in so many ways! :roll: :W

And if I go by those charts, I don't even need a tweeter in my systems anymore! So I must have just needlessly blown a bunch of money!



So how come I still like my 6640's and don't like my 662001?

[Hdale85]

Yeah that chart looks to be rather exaggerated, down almost 40dB at 8khz at 40 years old? I don't believe that for a second lol.

[dlneubec]

Interesting. :B I don't buy some of their data either, but it would be entertaining to hear a system with these in and then out to see just how much difference they make, good or bad. They remind me of a speaker I once owned back in the mid 70's, the Infinity 2000 II that had the Walsh omni super tweeter. I loved that speaker, but then that was 30+ years ago, now.

I once did a prototype 3way with an up firing tweeter that had a 360º omni horn (combo waveguide/diffuser just like my current project). I never took that speaker past prototype, but if I wanted to add a super tweeter, I think I could probably DIY something with better bang for the buck.

[JonMarsh]

Anyone here remember the Jantzen electrostatic add on tweeter modules in the late 60's and 70's? I had a friend that had those with some big KLH book shelfs. I doubt they were very flat, but they sure did have plenty of highs! :W

[dlneubec]

I'm a bit behind on updating this thread. I decided to start building the final design since the waveguides are on backorder until 12/11 and I need another 4 of them to complete a pair of speakers (unless I go another route - more on that later).

I got all the parts cut out for a pair, but went ahead and built one of them so I could take it to the Kentucky DIY event. It is probably 75%-80% done from a construction standpoint. I still have to do all the finishing and fix one mistake on the woofer box. The tweeter/360 horn is still in raw form, unfinished and without any resonance control in place for the plastic parts. I've decided how I want to mount them, which is shown in the photos below. I've included an adjustable flex-port like I used in the Chameleon's. You can this on the shot of the rear side. I still have a lot of little veneering to do on exposed edges before I get to sanding and finishing. The veneer is a burl maple with trim of Chechen. There is no finish applied at all so far.

The crossover has seen numerous versions. I initially had a fairly simple XO and then went to a more complex version that added parts primarily to improve phase tracking. I discovered that the version I took to the Kentucky DIY had one cap of a parallel set on the tweeter disconnected. Seeing this, I just decided to start over and have totally reworked the design. It is sounding very good to me again after the change. The parts are just cobbled together from what I have on hand. I'll probably do away with the use of Pcores in the final version. Also of note, the Transducer Labs N26C-G I'm using will be changed to the new round faceplate version of it when they come out later this year, I think. The round faceplate will make it easier to integrate into the look of the speaker and the new version is expected to have increased sensitivity by a couple db. Currently, I have no resistor in the tweeter XO, so a little more sensitivity could be beneficial.

I may end up having the entire waveguide/diffuser/horn turned from wood. Another PE Tech Talk member and I are discussing it.

I didn't take any photos during the construction of the speaker pictured below, but intend to do so when I build the second speaker.

[cjd]

How do you do the veneering? Cold press?

[Deward Hastings]

Anyone here remember the Jantzen electrostatic add on tweeter modules in the late 60's and 70's?

I had a pair of the JansZen tweeters made by Neshaminy Electronic (the four-panel units, similar to if not the same as the tweeter panels in the KLH-9 but splayed horizontally) that I used with AR1W boxes . . . would have been the early-mid 60's if I'm remembering the room I had them in correctly. Crossed at about 1kHz . . . leaving a bit of muddy lower mids, since that was really too high for the AR woofer. All the good things you'd expect from electrostatics, and all the bad . . . remember those were the days of vinyl and nasty cartridge resonances (and ears young enough to hear 'em). Still had them the year the V-15 was introduced . . . maybe 1964?

Better at what they did than anything else at the time, I have no idea how they'd compare to the better mids and tweeters of today.

[Hank]

Thanks Dan - progress! Further thoughts on dampening the wave guides?

[dlneubec]

How do you do the veneering? Cold press?

No, simple old, nasty contact cement. This is some very thick 2ply wood veneer.

[dlneubec]

Thanks Dan - progress! Further thoughts on dampening the wave guides?

I haven't done any more on that front so far. If I go the route of having laminated wood waveguide/diffusers turned, that will solve any resonance problems. If that route does not work out, then I will be searching for answers to dampen the plastic ones.

[---k---]

Looking pretty impressive. :T

[JonP]

I haven't done any more on that front so far. If I go the route of having laminated wood waveguide/diffusers turned, that will solve any resonance problems. If that route does not work out, then I will be searching for answers to dampen the plastic ones.

Shaping up nicely!

Had another thought on damping, rather than the Great Stuff like foam...

Once upon a time, my Dad was using a castable Silicone rubber to make epoxy molds. Stuff was a two part, catalyzed material, rather dense. Have no idea what it costs, whether it would melt the waveguides, etc... but you might research it and similar materials. Perhaps there's something, maybe non-silicone based, that would be a reasonable rubber like stuff.

Haven't talked to a friend of mine with a big lathe in a while, let me know if your other source falls thru...

[dlneubec]

Thanks, Jon. I'll see what I can find on the silicone rubber front. I'll let you know if my other option falls through on the wood guides.

[dlneubec]

Here is a thought. For inside the diffusers, I'm thinking maybe plumbers putty would work. It is very cheap, like $7 for 5 lbs at Lowes. I could probably line the walls with it and it would kill any resonance and maybe fill the remaining space with something the make sure the putty stays in place.

If I utilize a second waveguide over the first for the top waveguide it would create a narrow treatable cavity. Plumbers putty would probably not be plaible enough to work in the narrow space between the two wavguides (varies approximately from 1/4" to 1/2" or so), but maybe liberal strips of silicone caulk, spaced just enough apart so that air could get in and help it dry, would work and naturally conform to the space between the walls.

[Paul W]

The two-part "castable" silicons I've worked with will not stick to anything but silicon. Great release properties makes them excellent for molds.