Modula MT XE build

[sdl2112]

Here's my version of the Modula MT XE. After doing the Troels Jenzen project for my brother, I wanted something new for me. I have a longer term project in mind but it will likely take over a year to complete so I wanted something sooner...what better project than the MT XE considering I already have the tweeter/waveguide figured out.

I'm starting with the PE 0.75 cu ft curved cabinet in piano black with a custom baffle. This is an all out sort of project...I don't think too overboard, though I do have a few things up my sleeve. You will just have to stay tuned in to find out :B

This first pic shows the PE cabinet, I was very impressed :T The time it saved me...priceless! I plan to modify it for better damping...details to follow.


Preparing for port and connection cutouts


Done...one nervous step out of the way

[sdl2112]

Baffle construction

Since the PE cabinets use magnetic grills, so will I. I placed magnets in the baffles to line up with the grills.

For the baffle I'm using 1 inch bamboo ply mated with 12mm Baltic birch, the birch provided the same inset depth as the PE baffle.

Cutting the bamboo ply to size


Marking the placement for the magnets


Trial magnet fit on a scrap piece


Gluing the bamboo/birch

[sdl2112]

Baffle construction continued

Now on to the speaker cutouts...it's amazing how many operations this takes 8O Although wood screws would work fine in the bamboo/birch, the perfectionist in me wanted inserts. It allows more hardware options for driver mounting.

Marking the driver cutouts


Cutouts done, centering for mounting hardware


Rear woofer chamfer and insert clearance


Insert installation...really turned out nice...

[JonMarsh]

Nice work! The PE cabs are well made for the price, but still just a starting point- a lot of stuff left to do in addition.

Suspect I will enjoy watching this build unfold. I'm looking at revisiting this with some new drivers for Mini-monitors for the music room and for GF's bedroom. Gotta see if I can get one more pair of Anarchy woofers...

[jim1961]

Nice work as always Scott.

Going to have a Modula vs Gemini shootout at some point?

[sdl2112]

Nice work! The PE cabs are well made for the price, but still just a starting point- a lot of stuff left to do in addition.

Suspect I will enjoy watching this build unfold. I'm looking at revisiting this with some new drivers for Mini-monitors for the music room and for GF's bedroom. Gotta see if I can get one more pair of Anarchy woofers...

Those do look like nice woofers...I'm guessing you've seen the news about the resurrection of this woofer but just in case you haven't...
http://www.avsforum.com/t/1481860/re...ofer-in-4-ohms
http://techtalk.parts-express.com/sh...hlight=anarchy
http://www.diysoundgroup.com/feature...pre-order.html

Good luck!

[sdl2112]

Nice work as always Scott.

Going to have a Modula vs Gemini shootout at some point?

Well...I hope it's not too much of a shootout. I hope the Modula's win out easily

[dar47]

Nice work so far.
I'm glad your going for that hard baffle. Your going to really love this speaker it has crazy value and I still love mine. I just added a better pre-amp in the system and more detail came out. The MK2's will not hold you back.

So tell Jim to bring it on.

[sdl2112]

Nice work so far.
I'm glad your going for that hard baffle. Your going to really love this speaker it has crazy value and I still love mine. I just added a better pre-amp in the system and more detail came out. The MK2's will not hold you back.

So tell Jim to bring it on.

Thanks!...I've always admired how you did your integrated waveguide in the baffle. Glad to see you still love yours...that gives me more incentive to finish faster. I hope to have some waveguide details this weekend. btw...the Gemini's are my speakers so the shootout will not be much of a rivalry

[---k---]

Beautiful construction so far. Looking forward to seeing the completion.

[sdl2112]

Crossover

I worked on the crossovers this week ...actually got more done than expected...

I screwed the crossover boards to Baltic birch rails that I glued to the cabinet.

This is how I removed the wire varnish.


Crossover assembly


Placement in cabinet


Several beers later...soldered and complete :T

[jim1961]

My goodness. All that for a 2-way? Your crossovers are so pretty, a 30"x40" blowup picture on a wall might be kinda arty :B

I remember back in the day, the entire crossover was sometimes a single cap on the tweeter and that was it.

On a personal note, I rewired my passive pre-amp with KCAG One meter paired lengths of that stuff is up to $600 now :E

[JonMarsh]

Nice looking work! You're really moving along at a brisk clip! :T Clean looking crossover boards!

[wkhanna]

Agreed!
These are going to be some Premium 2-ways!
I especially like how he works well with beer. :T :^x

[sdl2112]

My goodness. All that for a 2-way? Your crossovers are so pretty, a 30"x40" blowup picture on a wall might be kinda arty :B

I remember back in the day, the entire crossover was sometimes a single cap on the tweeter and that was it.

On a personal note, I rewired my passive pre-amp with KCAG One meter paired lengths of that stuff is up to $600 now :E

Yes...I like the pretty colors. Jon did say this was the perfectionist version

[sdl2112]

Nice looking work! You're really moving along at a brisk clip! :T Clean looking crossover boards!

Thanks! It kind of gets obsessive once you get going...I still have a lot to do including modifying the stands. I should have an update later today.

[sdl2112]

Agreed!
These are going to be some Premium 2-ways!
I especially like how he works well with beer. :T :^x

Yea...that reminds me to double check my connections :roll:

[sdl2112]

Waveguide construction

I worked on adapting a waveguide to the D2608 tweeter a while back. I tried to create a smooth interface at the throat of the waveguide. I tried the H-65 but ultimately went with the Jantzen guide. I ended up using those guides elsewhere so I needed to modify a new one. I also created a new adapter to mate the diameter of the tweeter to the waveguide opening. It just so happened that a PVC reducer worked perfect :T

Not sure anyone would want to go through the trouble of doing this but here's how I did it...

I first milled out the tweeter faceplate to create a level surface and reduce the gap. I also milled the Jantzen guide base to remove about a 1mm step.

Milling the Jantzen base


Creating the waveguide adapter from a PVC reducer


Preparing for assembly


Finished pair :T

[J-Dub]

Awesome build!
Cant wait to see the results!

[JonMarsh]

I worked on adapting a waveguide to the D2608 tweeter a while back. I tried to create a smooth interface at the throat of the waveguide. I tried the H-65 but ultimately went with the Jantzen guide. I ended up using those guides elsewhere so I needed to modify a new one. I also created a new adapter to mate the diameter of the tweeter to the waveguide opening. It just so happened that a PVC reducer worked perfect :T

Not sure anyone would want to go through the trouble of doing this but here's how I did it...

I first milled out the tweeter faceplate to create a level surface and reduce the gap. I also milled the Jantzen guide base to remove about a 1mm step.

Milling the Jantzen base
[ATTACH=CONFIG]22308[/ATTACH]

Creating the waveguide adapter from a PVC reducer
[ATTACH=CONFIG]22309[/ATTACH]

Preparing for assembly
[ATTACH=CONFIG]22310[/ATTACH]

Finished pair :T
[ATTACH=CONFIG]22311[/ATTACH]

Slick... we should append this info to the original build thread! I'm looking at doing a similar build again, this is a help.

[dar47]

That white PVC rim makes the tweet look like a spy camera hidden in some bamboo. 8O

This could be a good thing, mine look so small next to all the wood and Jon's just disappear in the black wave guide.

I like those clamping bars, where did you get them?

[sdl2112]

That white PVC rim makes the tweet look like a spy camera hidden in some bamboo. 8O

This could be a good thing, mine look so small next to all the wood and Jon's just disappear in the black wave guide.

I like those clamping bars, where did you get them?

Yes the waveguide makes the tweeter look sooo much bigger

The clamps are from Woodpeckers...I think they were on special...

http://www.woodpeck.com/

[sdl2112]

Slick... we should append this info to the original build thread! I'm looking at doing a similar build again, this is a help.

I do like the Jantzen waveguide...it is very solid and inert. There are interesting alternatives with great results...makes my solution look too complicated :W

http://www.pellegreneacoustics.com/

[jlaakso]

I do like the Jantzen waveguide...it is very solid and inert.

I have my waveguides from the same material (POM) and there is no going back to molded plastic waveguides. Too flimsy after handling 1lbs waveguides

[sdl2112]

I have my waveguides from the same material (POM) and there is no going back to molded plastic waveguides. Too flimsy after handling 1lbs waveguides

Yes, I completely agree :T

[sdl2112]

Cabinet damping

The PE cabinets are well constructed but I wanted to improve the panel damping. I thought...what better way than lead sheet I wasn't sure how I was going to install it but it turned out quite well. I went with 1/8" sheet, any thicker would have been very difficult to cut and mold.

I tried three different adhesives before applying it to the cabinets. I haven't liked polyurethane glues in the past so I tried two water based Loctite adhesives in addition to the PL polyurethane. The PL specifically mentions lead bonding, it worked well and that is what I used. I usually prefer the water based products because of cleanup...I'll use the Polyseamseal to attach the wool felt to the inside of the cabinet.

Here's the adhesive test


Cutting the lead sheet to size...a little time consuming 8O


Applying it to the cabinet


Installed pic 1


Installed pic 2


In total the lead should add about 18 lbs per cabinet...:T

[sdl2112]

Tip of the day

I had concerns to the proximity of the lead sheet to the air-core inductor. I have seen nonferrous materials used as shields before so I performed a little test. I placed the 3.3mh inductor atop a lead sheet sample (To the sides it virtually had no effect, only when placed in the center). It reduced the measured inductance to about two-thirds its value. The flux from the coil will produce eddy-currents that produce an opposing flux to that produced by the coil, thus reducing the inductance. On the other hand if a ferrous material were placed in the center of the coil the inductance would increase.

I also tried aluminum with the same results so anyone making aluminum cabinets...take note

Here's the testing

[JonMarsh]

Yeah, it's important to keep inductors away from large sheet conductors, of any done of material, for exactly the reasons you mention! BTW, where did you get your lead sheet?

[sdl2112]

Yeah, it's important to keep inductors away from large sheet conductors, of any done of material, for exactly the reasons you mention! BTW, where did you get your lead sheet?

I purchased the lead from http://www.zipmetals.com/Sheet-Lead-_c_1.html. The 1/8" x 12" x 48" sheets were $60.50 each a couple weeks ago now I see it's already up to $89 8O...still a lot cheaper than McMaster.

[sdl2112]

Progress...

With the long weekend...I have some progress.

More cabinet damping....exciting...right!

In addition to the lead sheet, I also added some Cascade VB-3


Then some F13 felt


Additional bracing


Baffle support

[sdl2112]

Stand modification

My speaker stands have a small mounting surface which works well for my Gemini's but I need something bigger for the Modula MT's. I traced the outline of the PE cabinet and used a template guide on my router.

pic 1


pic 2


pic 3

[sdl2112]

Finishing

I applied one coat Seal-A-Cell, two coats gloss and one coat satin Arm-R-Seal. Installed the crossovers...getting pretty close :W

Sanded ready for finish


Last coat waiting to dry


Crossovers installed

[jim1961]

Have you listened to them yet?

[sdl2112]

Not yet...I'll probably glue them up today. Actually I'm a little burned out...this is all I've done this weekend.

[jim1961]

Not yet...I'll probably glue them up today. Actually I'm a little burned out...this is all I've done this weekend.

Sounds like the part that burned you out is about over. Soon you can just enjoy

[JonMarsh]

Not yet...I'll probably glue them up today. Actually I'm a little burned out...this is all I've done this weekend.

Lucky you, even though burned out! Looking very good! :T

[sdl2112]

Lucky you, even though burned out! Looking very good! :T

Yes...I can't complain. The idea of doing real work on a holiday weekend is no fun at all.

My girlfriend was out of town this weekend so it was speaker building marathon weekend I'm actually going to finish these a lot faster than expected.

[dar47]

I don't think that baffle will resonate much, but way to go on the over kill I like it :T.

[sdl2112]

I don't think that baffle will resonate much, but way to go on the over kill I like it :T.

When you have scrap material laying around it's like what the heck...might as well put it to use

[sdl2112]

Final assembly

Time to put it all together :T

I added loose wool stuffing to the cabinet and silicone foam gasket to the drivers.


Wow!...I was surprised at what these weighted in at...to the knuckle test they are dead...very dead.


Assembled with and w/o the magnetic grill


Front and rear...terminal block is for tweeter padding...std is 10 ohm, 8 ohm and 12.5 ohm are the options.


If anyone was curious why there are extra mounting holes in the mid-range cutout....well...I want the option to re-purpose the cabinets. I have Accuton C173-6-090 mids and Scan-Speak D3004/6640 tweeters I may use as a MT top plus bass cabinet for my next project. Good to have options .

[sdl2112]

Testing

Testing to see there are no problems...

Impedance of both...check :T


SPL...


0_15_30_45 deg horizontal at 1M


2nd and 3rd harmonics at 1V...very low...to make sure...I compared with my Gemini's under the same condition below.


Dynaudio Gemini's

[JonMarsh]

Time to put it all together :T

I added loose wool stuffing to the cabinet and silicone foam gasket to the drivers.
[ATTACH=CONFIG]22490[/ATTACH]

Wow!...I was surprised at what these weighted in at...to the knuckle test they are dead...very dead.
[ATTACH=CONFIG]22491[/ATTACH]

Assembled with and w/o the magnetic grill
[ATTACH=CONFIG]22492[/ATTACH]

Front and rear...terminal block is for tweeter padding...std is 10 ohm, 8 ohm and 12.5 ohm are the options.
[ATTACH=CONFIG]22493[/ATTACH]

If anyone was curious why there are extra mounting holes in the mid-range cutout....well...I want the option to re-purpose the cabinets. I have Accuton C173-6-090 mids and Scan-Speak D3004/6640 tweeters I may use as a MT top plus bass cabinet for my next project. Good to have options .
[ATTACH=CONFIG]22494[/ATTACH]

Now that's an option worth moving to the head of the class! :T

Four gold stars for you today! :B

[JonMarsh]

Testing to see there are no problems...

Impedance of both...check :T
[ATTACH=CONFIG]22495[/ATTACH]

SPL...
[ATTACH=CONFIG]22496[/ATTACH]

0_15_30_45 deg horizontal at 1M
[ATTACH=CONFIG]22497[/ATTACH]

2nd and 3rd harmonics at 1V...very low...to make sure...I compared with my Gemini's under the same condition below.
[ATTACH=CONFIG]22498[/ATTACH]

Dynaudio Gemini's
[ATTACH=CONFIG]22499[/ATTACH]

Looks just like where you ought to be! :T Nice work on this build! and documenting it, too!

But seeing these kind of results again makes me wonder if perhaps I shouldn't build the TMM concept version of this, perhaps even with the 6640 tweeters, as our music room monitor, in a fresh cabinet build? (instead of the Deluxe NatP concept build to verify the design for Bill). (should do the latter anyway- at least one cabinet- but this build of yours reminds me of all the things I like about the XE, and maybe it's time to revisit that? )

[dar47]

Completed vary nicely! How do like the sound? You better have a nice sounding room to take advantage of your planned upgrade.

You guys are killing me, I said I wouldn't touch the XE's but now I'm going to be fighting this next step.

[jim1961]

The re-purpose aspect makes a lot of sense, and could save considerable work for your next project. Great planning ahead and foresight Scott!

Have you considered building subs next that would meet the specs for your Accuton build and also integrate with the Modula's ?