Understanding the Zaph Waveguide TMM crossover diagram

[mikan]

waveguide mods...

 

[xyrium]

Ahh, nice work! I will say, that's pretty nice "weed".

I have a question about the bottom of the cabinet though. Don't you think that empty space will become a slightly resonant chamber? Maybe enclosing it and filling it with sand would be good?

 

[xyrium]

BTW, I'm extremely eager to hear about your listening impressions once they break in. I am considering this design as well for a dedicated room. If these can play down to 50Hz in a 15x13" room with authority, I'm sold.

 

[mikan]

Ahh, nice work! I will say, that's pretty nice "weed".

I have a question about the bottom of the cabinet though. Don't you think that empty space will become a slightly resonant chamber? Maybe enclosing it and filling it with sand would be good?

Given that it's open at the front and rear and therefore not strictly a chamber, I'm not at all worried about resonance problems.

BTW, I'm extremely eager to hear about your listening impressions once they break in. I am considering this design as well for a dedicated room. If these can play down to 50Hz in a 15x13" room with authority, I'm sold.

I'll post my impressions when they're done, and will try to compare them to a similarly spec'ed commercial speaker.

 

[xyrium]

Thanks Mikan. Oops, I hadn't realized the back was open!

I did the L15 design that Krutke made, and I love it. I was considering the L18 system he designed, but now I'm thinking that this one might be better. The L18 has twice the Xmax of the C18 series woofer, so I was thinking that even one L18 may have more impact than two C18s since they aren't both creating bass, though the radiating surface area would be considerably reduced.

If I do this one, I'm thinking of purchasing the 38l cabinet from Madisound since I don't have a table saw...so I'd rather concentrate on getting the waveguide mounted as well as possible.

 

[mikan]

The L18 has twice the Xmax of the C18 series woofer, so I was thinking that even one L18 may have more impact than two C18s since they aren't both creating bass, though the radiating surface area would be considerably reduced.

The WaveguideTMM is 2.5 way, so both CA18RNXs do bass .

If I do this one, I'm thinking of purchasing the 38l cabinet from Madisound since I don't have a table saw...so I'd rather concentrate on getting the waveguide mounted as well as possible.

I don't have a table saw either - I had the MDF cut to size at the cabinet maker that supplied the MDF. They did an excellent job - all panels are +/- 0.5mm and square, and fitted together well. It was cheap too - AU$120 for the cut to size MDF, with the added advantage of no MDF dust .

My tweeter mount differs from Zaph's - M6x60 capscrews are used to sandwich the waveguide, tweeter and mount together. This method should be easier to construct and more robust than having separate screws for the waveguide and tweeter working against each other. I haven't built this yet, but see the attached CAD. The four M6 capscrews pass through the waveguide and nyloc nuts pull up against the mounting board.

 

[xyrium]

Getting the panels cut is certainly something to consider. We shall see.

I was under the impression that the xover design (the "perfectionist version) frees up one for more mids than bass. I'll have to read his description again!

I like the idea of the cap screws. I don't want any air leaking out of the tweeter mount, so anything to secure the driver and flange in place is a good idea! Thanks!

Rgds,
Paul

 

[BobEllis]

I'm using the AJinFLA method for attaching my tweeters to the waveguides - fill the back with auto body filler and then trim flush when you rout the opening. The tweeter then screws to the back of the waveguide and this assembly mounts as if it were a single piece.

I haven't drilled the tweeter mounting screw holes yet. I think I'll try self tapping sheet metal screws first. If that doesn't work well, I'll make my own threaded inserts by drilling over sized holes, filling mostly with epoxy and inserting screws that have been sprayed with oil (WD40) so they don't stick. A waxed paper gasket should keep the tweeter body from sticking if the "inserts" overflow.

 

[xyrium]

Thanks for the tip. I'll check out the thread on AJinFLA for this project as well!

 

[BobEllis]

AJ is a member name - he did an Orion like open baffle speaker using the 27TDFC in this waveguide. Somewhere in there he described it, but it isn't a whole lot more than fill the back with body filler and rout it flush. You have to remove the threaded portion as Zaph mentions, but otherwise my router did not respond differently to the filler than the waveguide.

 

[peace brainerd]

Very, Very nice Mican!!
So happy to see so much interest in this project.
I'm going to get started on it myself pretty soon.

I'm considering a poured concrete baffle. There is
a shop down the road from me that does kitchen
countertops, so I think I can get some excellent
advice.

I'll order the MCM waveguide, router it down as
Zaph describes, and use it as a mold to make a
negative profile with liquid rubber - place this in my
baffle mold, mold-in-place the speaker "cutouts"
and edge radii, mix-mold-release, and... presto?

I've done a few poured concrete lawn ornaments,
shop floors, garden steps, and door thresholds,
so I'm somewhat along the learning curve. This
is going to require much finer detail, fewer voids
and imperfections, and some form of fiber reinforcement
to resist cracking in the thinner sections. Hopefully
the shop down the road can offer advice.

And hopefully I'll have a few buddies nearby if I
ever have to move them to another house.

 

[xyrium]

AJ is a member name - he did an Orion like open baffle speaker using the 27TDFC in this waveguide. Somewhere in there he described it, but it isn't a whole lot more than fill the back with body filler and rout it flush. You have to remove the threaded portion as Zaph mentions, but otherwise my router did not respond differently to the filler than the waveguide.

Yep, I've read quite a few of AJ's posts much to my own entertainment. He's obviously been a valuable member to this board. I saw the waveguide system he built, I think, using plaexiglass as the baffle. Very interesting, and attractive system. I certainly don't have the skills he has, but the Bondo sounds like a great idea. Thanks again!

 

[MacT]

Hello everyone
I'm new to diy and as my first project i've chosen Zaph's TMM waveguide. My question is - can I implement it in smaller cabinet? Not in 38 l (2x19,5 l) but in 27 l (2x13,5 l). These ones i own and do not want to spend money on new ones What should I expect from smaller cabinets? Just less bass or something worse?
Thanks for any reply

 

[tinitus]

Hello everyone

Not in 38 l (2x19,5 l) but in 27 l (2x13,5 l).

What should I expect from smaller cabinets? Just less bass or something worse?

I tried calculate with Zaphs specs and 24liter netto should be ok
27liter would be ok, as long as we speak inner volume

Port around ø70mm x 160mm
But may need adjustment

I havent looked closer at Zaphs design, but the smaller box would have a higher rolloff with -3db around 55hz, and -6db just below 50hz

edit
But if you will need a standmount it could be used to give a bit more

 

[paulspencer]

I suggest that you sim both with Win ISD pro alpha. Start with the Zaph version, then do the smaller version and see what you get. This is what we would need to do in order to give useful feedback on the change.

 

[mayhem13]

I did a sealed version in 28L using the RLY version woofer instead of the RNX for HT duty with subs......sounds great with LOTs of power capability. I'm actually doing a second set now. I also did the molded epoxy waveguide mod instead of the screwed in backer board.