Jeff B's CSS Triton High Resolution Monitor - build thread

[bkeane1259]

At InDIYana 2012 I was the extremely fortunate door prize recipient of the Jeff B designed CSS Triton kit. This was quite ironic since I thought the Tritons had the best and most lifelike midrange I have ever heard in a speaker – to the point it was scary. I’m sort of a sucker for a good sounding guitar and the string reproduction on these MTMs was by far the best I have ever heard. I was running the live video stream during the demos and many of our virtual attendees also had great things to say about the amazing sound of the Tritons – yes, over a video stream. Go figure.

I have been bogged down with other projects in addition to all the “life things” that get in the way of projects, but I am dead set on getting these done in time for Iowa. So this will be a short and sweet build thread.

I won’t go into any detail on the actual drivers -- CSS VWR126X and LD25X – Instead, I have included a couple excerpts from the man himself - Jeff Bagby:

After having had a chance to work with Creative Sound’s new little tweeter, the LD25X, which is a real gem and one of the cleanest, lowest distortion tweeters I have ever seen, I got the opportunity to design an MTM using this tweeter and CSS’s new VWR126X driver.

The VWR126X is a “very wide range” (VWR) 5 inch nominal cast-frame driver. Like the LD25X it features the XBL™ motor topology, and it has an approximately 3” thermo-set woven polypropylene cone with a copper colored aluminum cap on the voice coil former. This is not a driver that can deliver prodigious amounts of bass, but its nonlinear distortion levels in the midrange are world class. Using two of them in a symmetrical MTM design will help to couple with the air a bit better and help extend the response a bit deeper in a reasonably sized enclosure.

The Tritons are flat within +/-1.5 dB in quasi-anechoic measurements from about 52 Hz up beyond 20kHz. Above 100Hz the nonlinear distortion is world class, a testimony to the design of these remarkable drivers. In my listening tests the Tritons recreated the most pin-point imaging and spacious soundstage I have heard in a very long time. The speakers made their public debut at the “InDIYana 2012” DIYer gathering in Fort Wayne on April 14, 2012. Feedback revealed that many of the attendees selected the Tritons as having the best midrange reproduction of any speaker at the event.

Here are some squigglies:

[bkeane1259]

Sometimes all your stars are in alignment. At InDIYana 2012, Mark @ Meniscus just happened to have a pair of old cabinets that were temporarily used in a Triton prototype. The Meniscus dudes always have a van full of toys and I was able to score these cabinets. All I need to do is some touch-up work, bracing and damping and front baffles. The cabs were in fairly good condition as I got them – just a little dinged up here and there and they will need to be re-veneered eventually, although I’m not so sure the new veneer will get done soon enough for the show. The cabinets are mitered 3/4" MDF - 18” tall x 7.5” wide x 11” deep. There will be a front-mounted slot port.







The front baffles will be removable. 1-inch square poplar corner braces will hold threaded inserts, and I will also tap the center brace for mounting bolts.

[bkeane1259]

The more I use it, the more I like it. PE's Sonic Barrier vinyl damping is added to the back side of the front baffle. The baffle material is 1-inch thick poplar. I plan to add a 3/4" roundover to the baffle sides.







The Sonic Barrier adhesive is very good. I didn't use additional adhesive, but I did hit it with the heat gun and a small J-roller before clamping the two baffles together. Gonna let that sit overnight just to ensure a good bond.



Additional vinyl damping was applied to the inside panels and I hit the whole interior with truck bed liner.



That's it for now.....

[isaeagle4031]

Looking good Brian! I've been bouncing back and forth on which tweeters I want to use in my 3ways with the ld25x topping the list. I think now I am going to pull the trigger and go with them. Are you planning a sub to mate up with these? That was really their only downside.

[arlis_1957@yahoo.com]

nice build thread. cant wait to hear them in grinnel.

[bkeane1259]

Thanks guys. Chuck, I do have a sealed JBL GTO1214D at my workstation that I only use once in a blue moon to be honest. Initially I will be swapping my Speedsters out for the Tritons. There's a world of difference between those two speakers, so it will be very interesting to get this build done and get the Tritons installed for some break-in and listening ahead of Iowa.

[bkeane1259]

Verified the driver spacing from a high resolution picture I have from the last InDIYana gathering. Thank God for Photoshop. Even though this particular picture is at a slight angle, I was able to zoom in to actual size and verify vertical dimensions with a digital caliper. Then I cropped the picture and added a grid to double check. Basically the grid measures 1/2" increments. So the spacing is as follows in the picture below.

[ryanbouma]

Cool stuff.

Did you see this: http://www.diyaudio.com/forums/multi...ml#post3194513

I think it's kind of weird. I wonder if Jeff is actually aware of this. It sounds like that RAW guy is trying to step in or something. I dunno. I'd send Jeff a pm if I were you, unless you already have this "updated" cross over.

[NyxOne]

Cool stuff.

Did you see this: http://www.diyaudio.com/forums/multi...ml#post3194513

I think it's kind of weird. I wonder if Jeff is actually aware of this. It sounds like that RAW guy is trying to step in or something. I dunno. I'd send Jeff a pm if I were you, unless you already have this "updated" cross over.

I believe "Raw" is the former owner of Raw acoustics and has worked extensively with CSS (Bob) over the years. Just like Jeff, he knows what his doing! His suggestion (cap across the tweeter legs) is legit depending on how lively you like your tweeter.

Chuck

[ryanbouma]

Yup, he does work with Bob. And I agree that a cap across the terminals would tame the top end. Just seemed odd to me how he put it. Especially the last part about listening to his cross over. I dunno, maybe Jeff knows they're modifying his cross over and that is cool. I just figured I'd point it out to the OP so he can enquire if there is a better xo.

PS. I usually find a series resistor will tame the top end with more control and cheaper. I wonder if they tried that. Good luck Bryan.

[Jeff B.]

Yup, he does work with Bob. And I agree that a cap across the terminals would tame the top end. Just seemed odd to me how he put it. Especially the last part about listening to his cross over. I dunno, maybe Jeff knows they're modifying his cross over and that is cool. I just figured I'd point it out to the OP so he can enquire if there is a better xo.

PS. I usually find a series resistor will tame the top end with more control and cheaper. I wonder if they tried that. Good luck Bryan.

To my knowledge the "new crossover" was the identical schematic but with boutique parts. I was unaware that the design itself was being modified. It seems so far everyone has loved this speaker, so I guess that's why we want to modify it.

[bkeane1259]

The only "update" that I'm aware of is a "dual board" XO that separates the hi-pass filter from the low-pass filter and as such, increases the spacing of the inductors. They also rotated the small inductor in the low-pass circuit. Funny since I got this shortly after bringing it up in another thread (about the inductor orientation).

I have only heard this system with the original XO as designed by Jeff and I won't be modifying it for Iowa. I want them to sound like I heard them in Indiana.

[bkeane1259]

Here's the dual board XO:

[bkeane1259]

Got the front baffles done today. Drivers are horizontally centered on the baffle. Vertically, moving from the top of the baffle, the first VWR126 is mounted 1-inch from the baffle edge. Then CTC driver spacing is 4.225”. This will leave ¼” between the tweeter and woofers. All drivers are to be flush-mounted.



I have to say the VWR126 was a bit challenging for me to cut the proper recesses and mounting holes. The actual driver diameter is 4.953125 (4 61/64”), but my Japser jig only increments in 1/16ths, so the question becomes do I go smaller and sand or larger and live with it? Well, I tried smaller (4 15/16” on the jasper jig) and the sanding was a real pain in the a$$, plus I managed to kill the perfect “circular shape” of the recess with my sanding, hence the first baffle defect – yay. The driver fits really tight as seen below and you can also see the unevenness of the circle. In the end I opted to go to a 5” diameter and a ¼” deep recess. Since I am painting the baffles, I can build up some paint in the mounting holes and get a really snug fit. I used a slow progression on the Jasper jig to create the recesses. Plunging the router bit ¼” and starting with a 5” circle, then 4 5/8, 4 5/16, 4 and then finally 3 13/16” and this is where I cut all the way thru the baffle. It leaves good room for mounting screws. I will have to chamfer the backsides of the baffles a lot. The VWR126 does not have large basket vents. Oh, one more thing. You have to notch out some material for the driver terminals. This will be seen in the next post.

This cutout is 4 15/16 plus a fair amount of sanding to get the driver to fit.



This cutout is 5” and it is obvious. The driver isn’t centered so the cutout doesn’t look circular, but it is. With some paint build-up around this cutout it will end up fine.



The depth of the recess is ¼” and I think this will be fine, even using the supplied gasket.



I’m the first to admit that I am not good with flush-mounting drivers. If there’s an easier way, can somebody please clue me in? TIA.

[bkeane1259]

The tweeter cutout was pretty straight forward. The LD25X has a 3” diameter. I did a recess depth of 1/8”. The router bit progression on the Jasper jig is as follows: At 1/8” depth - 3”, 2 5/8, 2 3/16 and then 1 15/16” and this is where I went all the way thru. FWIW, I tried a 1 7/8 thru hole on scrap and the tweeter cup did not fit well.



Baffles with driver cutouts – note the notches for the woofer terminals.



Making the front baffles removable, so I marked the center location points for the internal mounting braces, clamped the oversized baffles on as straight as possible and drilled small pilot holes. From these pilot holes I will drill counter sinks for the connector bolts on the baffle and I will install threaded inserts into the internal mounting blocks. I'm using the long connector bolts and inserts from Meniscus.

My son helped me measure and mark the baffle mounting points.



Countersink holes for the baffle bolts.



I didn’t have time to cut the slot port opening on the baffle, but I made a painter’s tape template that I will use on the baffle to mark the opening. My plan is to use a slightly smaller forstner bit and drill a series of thru holes. Then after the baffle is attached, I will simply flush-trim the opening. Sounds easy right? I fear a potential screw up there, but we’ll see tomorrow.

[rx7mark]

Bryan,
Really looking forward to you impressions of the Tritons, especially relative to the Speedsters.

Looking great so far, following along very closely.

Mark

[fdieck]

Here's the dual board XO:

I believe the woofer crossover board wiring shown is wrong as shown. A series connection to the woofer throung 0.72 uf will give no bass. I would think the woofer should be connected to the induction junction with the 0.72 uf cap and the other end of the 0.72 uF cap returned the All-. The build photos are great and proof that beauty is more than skin deep with it comes to loudspeakers. I am envious of your skill!

[ryanbouma]

I don't see a 0.72uF cap. But if you mean 0.47uF cap, that's done right. It's a notch. The bass can travel through the 0.25mH inductor.

[fdieck]

I don't see a 0.72uF cap. But if you mean 0.47uF cap, that's done right. It's a notch. The bass can travel through the 0.25mH inductor.

Whoops! Mistook the 0.25mH inductor for a 0.25uH cap at quick glance...... no more circuit analysis in the morning before coffee

[bkeane1259]

I don't see a 0.72uF cap. But if you mean 0.47uF cap, that's done right. It's a notch. The bass can travel through the 0.25mH inductor.

Correct. Jeff addressed a high-frequency spike in the woofer due to the aluminum dust cap with that 0.47uF/0.25mH notch filter. The Dual board XO is correct as is.