[swnewell]

After reading most the threads on waveguide speakers over the weekend I decided to order 3 QSC waveguides (PL-000446-GP) this morning. I am planning on building Zilch's deluxe econowave (AK and PE Tech Forum) w/ the XO designed by Schumacher (it's not plagiarism if you acknowledge the source

). Originally I wanted to build on the QSC HPR 153 horn assembly (PL-000447-GP) but the community clearly favors the two-way approach over the three-way (as a novice I went with the flow).


The drivers that the XO was developed for are the Eminence Kappalite 3012LF 12" driver and the B&C DE250-8 CD. I noticed that the 3012HO driver selected by augerpro for his No Quarter build has greater sensitivity - but since I want to use the Schumacher XO I will go with the LF version.


Speakers will be driven by 130 W/ch from an Onkyo 805 receiver in a large, open basement. Subwoofer is a Mal-X 24" sealed cube based on NeoDan's enclosure. Listening will be 60% HT and 40% music (70s metal [Sabbath, Maiden and Metallica], classic rock [Petty, Kansas, and Floyd], and jazz/blues [Coltrane, Davis, and Terry Evans]). I typically listen at -10dB THX reference when family is home, and 0 dB reference when I have the townhome to myself (rare since I travel all the time for work). Current speakers are 16 yr old Paradigm 9seMkIII's that were fine until I added the Mal-X sub and now they cannot keep up - and noticeably are not very dynamic in such a large space (~3500 cu.ft.)


I don't plan on using the Trapezoid enclosure and will build my own as this is the fun part of the project. From the PE site I cannot tell if the enclosure is ported? I have tried reading the econowave build thread on AK, but at 656 pages it is a bit long (and I cannot get the photos to load, even though I registered for the site). I ASSUME that the enclosure size is essential to the XO design, is this correct?


I tried using modeling software when building my subwoofer and conceded defeat.


The T/S parameters for the 3012LF woofer are:

Resonant Frequency (fs) - 37.02Hz

DC Resistance (Re) - 5.6

Coil Inductance (Le) - 0.98mH

Mechanical Q (Qms) - 6.94

Electromagnetic Q (Qes) - 0.34

Total Q (Qts) - 0.32

Compliance Equivalent Volume (Vas) - 106.65 liters / 3.77 cu.ft.

Peak Diaphragm Displacement Volume (Vd) - 496cc

Mechanical Compliance of Suspension (Cms) - 0.26mm/N

BL Product (BL) - 16.7 T-M

Diaphragm Mass inc. Airload (Mms) - 72.4 grams

Efficiency Bandwidth Product (EBP) - 109.7

Maximum Linear Excursion (Xmax) - 9.1mm

Surface Area of Cone (Sd) - 545.4 cm2

Maximum Mechanical Limit (Xlim) - 14.5mm


I like the looks of the cabinets used by Augerpro and Penngray in their build threads and plan on building something similar. I would like to have the woofer in its own enclosure, with the waveguide in an open baffle (along the lines of the Martin-Logan speakers) purely for looks.


Any suggestions on alternatives would be greatly appreciated, as I will not be ordering the drivers for a while (I have not told the wife I ordered the waveguides, but at $12.50/ea she will never notice).


The amount of information and technical ability available at this, and other sites, is amazing. Thanks in advance for comments and assistance.


Best,


SWN

 

[penngray]

Awesome, its great to have another QSC build!!

I will have to read up on that crossover, I need to understand how they handled the CTC and phase stuff.

 

[swnewell]

I don't think my open baffle idea will work. I was drawing the enclosure to scale and by making a seperate woofer enclosure will spread the distance of the woofer and waveguide assembly. I am sure this would not be good for the XO design. I also assume I need to stick to a front baffle width that is pretty close to that of the trapezoidal enclosure used by Zilch, since the diffraction is part of the XO design(???).

 

[mynym]

Excellent!


Take lots of pics.


I've already sold myself on Zilch's deluxe econowave for my spring/summer DIY project.

 

[swnewell]



Quote:
Originally Posted by mynym /forum/post/18189337


Excellent!


Take lots of pics.


I've already sold myself on Zilch's deluxe econowave for my spring/summer DIY project.

Not sure how long it will take to purchase all the materials, haven't ran it through the family accountant (aka wife). She is still a little upset by all the tools I had to purchase for my sealed Maelstrom-X subwoofer build last summer. But now that I have the tools they need to be exercised or they will get fat.


I spent much of today over at the PE Tech Talk Forum discussing parameters with the designer of the deluxe XO (Schumacher). Looks like I will go with a 3.0 cu ft cabinet, sealed. No real need for ported as I will cut the speakers off at 80 Hz (per THX specs).


I am not sure of the dimensions yet, I need to measure the available distance under by projector screen so I can run all three across the front of my room. Unfortunately I am out-of-state much of the time for work so this build will be painfully slow. I will take a lot of pictures once the sawdust starts to fly.