Well, I finally jumped in with both feet and completed my first speaker main build. After much reading on many forums for new L/C/Rs for my media room, I settled in on Zilch's Econowave SR as a low budget high performance build.

What I wanted was a relatively compact L/C/R that was high efficiency but not harsh in the highs, and was very budget friendly. I am coming from Infinity primus 362's as mains, with a PC350 center. The highs were smooth with those, and had OK detail at low volume, however for in my media room, they compressed badly, and suffered from lack of midbass being driven with my Denon 100w/7 receiver. Go figure. The E-wave SR seemed to be in a "best buy" category for what I needed out of a speaker.

I also had auditioned some vintage Klipsch Hereseys and Cornwalls, and while I liked the detail, efficiency, and midbass, the highs were really harsh, and they didn't put up as broad of a soundstage as I would have liked. So they got sold.

I am pairing them up with a home built subwoofer - a 6.3 cuft tempest x2 enclosure slot ported to 18hz, that was 24"x48"x13" - flat enough to fit behind my 17" deep false screen wall. It's powered by a Dayton 500w HPSA amp, which provides good bass in the room, but I will likely be building a second sub to smooth out some significant room mode issues (does it never end???!).

Anyhow, enough background, on to the build!

The design:

I drew heavily on Augerpro's carcass and port design. I made some modifications to make them fit behind my screen wall while allowing the L/R's to be able to accomodate up to 25 degrees toe in - crossing about 2 feet in front of the couch. I needed to rear mount the woofer to get the accoustic offset needed, so I build a box with a removable back. I also didn't follow his design entirely in that I didn't have the 1 1/4" huge roundover, and as an "econo" build, I was trying to not have to buy more tools (I already have a garage full!).

Final dimensions: 25.5" x 16.5" x 11.25". Baffle 1" thick (laminated 3/4" MDF and 1/4" MDF). Sides and back are 3/4" MDF. Final volume about 1.65 cuft net.

Components: Dayton PA310-8 woofers, Selenium D220ti tweeters, QSC waveguide, and Zilch designed e-wave SR crossover.

Here are two of the three glued up carcasses, with a 1/4" recess for the waveguide (the hardest part of the whole construction process).

Here's a closer shot of the recess.


I opted for a side mounted 4" port, like augerpro, and the best location ended up being a bit higher in my box due to the T shaped cross brace. Because of the removable back, an x shaped brace that went to the rear wasn't really an option.

The woofer hole is pushed right up against the WG opening, and I opted to use a 3/8" roundover on the woofer hole (right into the WG), edges of the box, and for the port roundover as well.

I put together my first crossover - breadboard, with the recommended components from Zilch's "flex your PCD muscle" thread over at the Parts express TechTalk forums. Not too hard really, even for me with no speaker building experience.



And here's the finished product!


The back, with recessed L-pad and terminals. On the inside, I added a 1.5" wide x 3/4" thick plywood keel right down the middle of the removable back to minimize flex in that large panel


The trio (two with left ports, one with right).


And in their final resting place behind the AT screen. The bottoms of the speakers are just above the bottom of the visible part of the screen, and the left and right are toed in about 25 degrees.


I'm still forming my listening impressions, but early listening shows them to have better midbass than the Infinities, and have much more detail to the sound. They are not as "in your face" as the Hereseys, but only have slight high frequency harshness at high volumes, where the Heresey's were unbeareable. So far, early on, they are hitting on all cylinders of what I need for new HT speakers. They can keep up (and exceed) my current sub on a very modest 100w receiver. I don't notice any compression even at listening levels well above what I would use (they get loud!!). I'm still dialing in the l-pad - currently at about the 12:30 position. It's nice that I can dial in the HF section to taste and how it responds in my room. As I add side wall diffusion/absorption treatments, I may have to tweak the pad - nice to have the option.

Thanks to everyone, especially Zilch for the component design, and Augerpro for inspiration on a really nice box/port form factor. These are not going anywhere, and I need to put my Infinities up for sale now.

Best,
Christopher

Awesome!!

Have you considered using foam or treating the back of the waveguide?? having the woofer and the waveguide in the same box could be creating some resonance in the waveguide itself.

Whoops didn't mention that part. I did not treat the waveguide. I read about some people doing that to their guides, but it seemed really dull/dead after the driver was mounted and it was mounted firmly in the box.

The side of the box opposite the port, top of the box, and entire removable rear got 2" of fluffy fiberglass insulation, lightly spray glued into place. In other builds, that seemed to be an average amount of insulation added, and should be enough to tame the backwave and internal reflections.

The other thing I did was think about the port directions - as my L/R are toed in, the ports are on the side facing the back wall behind the screen, which is treated with 1" linaccoustic, to help absorb any HF spillage out the port.

Best,
C.

Cerdic

I like the build. What did you finish the boxes with, they look good.

Fine job! They look great!

Thanks. My finishing schedule was sanding to 400 to "polish" the MDF edges, a coat of 50/50 water/wood glue to seal the raw MDF edges, another final sanding to 400 grit. Base of BIN shellac based primer, tinted as dark as they could (ended up medium grey), with spray primer on the inside of the PVC ports. Resand, and topcoat (x2) with Behr ultra flat/matte in Mickey Mouse ears black. 1 quart did 2 coats. Applied everything with a foam roller, and a brush to get in the nooks and crannies.

The biggest problem I had finishing them was that the sanded primer was so slippery, it was like painting on glass. I had serious issues getting the first coat of black to roll on nicely. Lesson learned.

Best,
C.

Those are very nicely built. It will give you a nice upgrade path with the DE250 CD and the Eminence woofers if you wanted to try.

I went to Lowe's and got a roll of Peel-n-seal for $16. It was plenty enough to treat the backs of my horns (all 3) with some left over. And my horns are fairly large. This is the same stuff the car guys use instead of dynamat. Pretty cheap for a little piece of mind.

Do you have any pictures on how you back mounted the woofers as you were able to hide the screws?


Yes you want rear mounted woofers with that QSC waveguide because the drivers will align and it doesn't tilt it.

Is there a difference between rear mounting and flush mounting(double baffle) the woofer?

Wow very nice build Cerdic!

Love what you did with the back


I would look into putting something on the back of your waveguides. I built 3 Ewaves for my front stage and I put some fiberglass on 2 of the 3 thinking that I was going to run some tests, but never did. but to my ears just playing around I can hear a difference between the two for sure. Just thought I would throw in my 2cents for what its worth.

cheers

Nice to see what I am gathering parts to build.

Did you just use the EconoSR parts list for the crossover?

I can't express what a personal pleasure it is for me to see these builds in various forums, and I'm sure it's the same for Brandon (Augerpro)....

Thanks for all the kind words. To answer a few questions:


Yes, I used the exact parts list from the PCD thread for the crossover. When I have the rears off to add material to the WGs, I'll see if I can remember to snap a photo or two of the finished inside.


Alright, that's at least three votes for treating the back of the waveguides. I'll see what I can find at HD or Lowes and get back to y'all on the results when I pop them open and dampen the waveguides.


For the axis to be proper between the woofer and tweeter, the front of the woofer needs to be 3/4" behind the rear face of the waveguide. However you want to accomplish that. Since I recessed the waveguide 1/4", I made my front baffle 1" thick so that a rear mounted woofer would be the proper 3/4" spacing. You can make a double (or more) thick front baffle and make a recess for a front mounted woofer to get that same spacing, BUT, by doing so you are forced to space the woofer and tweeter slightly farther apart, which will result in a slightly compressed forward lobe. Since I don't have measurement equipment, I tried to make mine as close to spec as Zilch's prototype in that regard. Since I wanted a slight roundover of the woofer baffle lip, that meant extending into the waveguide slightly.



Check, got it. Will look for this same stuff at Lowes. I hear they don't carry the "peel-n-seal" anymore, but have a comparable product by another name. I'll see what they have tomorrow.


It was a fun project, but now I need to clean up the garage/workshop. It's still a mess from the project.

Best,
Christopher

Bah!

No point in cleaning up the garage 'til at least a week of listening evaluation is complete....

very nice work. the rear mounted woofs with routed baffle look very slick! this design has a lot going for it. props all around.

one thing that is a little concerning is that the port seems to have a length about equal to its width. at the moment, i foget why, but ports equal to or shorter than width potentially run into some sort of problem. not sure if it is just a modelling vs. actual tuning point or if it is something more.

separate enclosures for the horn and/or lots of damping seems to do a little better than having the horn in the same enclosure, undamped, with the bass driver.

I haven't read anything about short ports... the length of the 4pi port is about the same as it's height as well...? I think it may just be the nature of the beast of running a port tuning in the mid 50s. A 4" diameter 4" long port works, and shrinking the size to 3" or 2" shortens the port length to the same or less than the diameter if I recall correctly (without winisd right in front of me).

Is there some thought that I may need to stuff my cabs more thoroughly?

Zilch, how are your cabs stuffed? I seem to remember seeing one pic of the inside that looked like the cab was pretty full of pink insulation - is almost all the airspace taken up? (trying to remember where in which of the many e-wave threads I saw that..)

Edit: Looks like you lined all sides with about 3-4" of fluffy pink insulation. Did you ever run measurements, Zilch, with less damping material?

Best,
C.

Yes, the Acoustical Center is better with a rear mounted woofer.

I would like to see that link, I have not heard any issues with my ports that are wider then long.


Yeah, I built two different boxes one with the same enclosure and one with separation of the waveguide plus treatments on the back of the waveguide. Subectively there seems to be something better, I have no measurements comparing them though.

Nice looking speakers..I may have to look into these...

I have 3 Natalie P's behind the screen fed by pro amps and they quickly run out of headroom at louder listening levels.

"I would like to see that link, I have not heard any issues with my ports that are wider then long."

i can't find it...shucks...

Does the port matter where it needs to be placed?

I would have these in an open area for now but in the future they would be placed in a cabinet only slightly wider than the speakers themselves. So I was think rear firing on all of them based on future placement.

My cabinet design will have something very similar to your outer wall audio cabinets or whatever theyare used as.

What exactly is the acoustic center? I'm guessing this has something to do with the depth of the cd.

Isn't acoustical center the point at which sound actually is being reproduced/emitted from the horn or other?

In other words mounting the woofer on the rear is to try and get the CD and woofer to have almost the same AC or "starting point."

I am guesssing this is correct but I dont know much in commparison to others on this forum.

this is roughly the idea. depending on the delay from the tweet to the woof, you can move the middle lobe up and down.



http://forums.klipsch.com/forums/p/98353/993042.aspx

avs referencing a rane image on the klipsch board. i'm loving it.

Ports: http://www.harman.com/EN-US/OurCompa...ions/11094.pdf

Lobes & Nulls: http://www.pispeakers.com/misc/Vertical_Nulls.wmv

I'm nowhere quantified with respect to damping fill, other than working with "smallish" cabs, and using fiberglass exclusively. If BB6P shows me that "heavy fill" is better than "normal," I either use higher density or stuff more in, though in some cases, it's possible to have too much. Closed box, I use more to increase the virtual volume, but generally, it's "line the inside, stay away from the inside port opening, and leave some room behind the woofer...."

thanks for the links z.