Flex Your PCD Mettle:

[Mayhem13]

Re: Flex Your PCD Mettle:

Will this thread never die? The horse is dead, it's bones are fossilized...

Given the contents contribution to the hobby, thank god it's still going. We certainly don't need any more 5" dome tweeter two ways now do we. There;s something worth givin up the ghost.

[Russellc]

Re: Flex Your PCD Mettle:

We are pikers here; the main thread on AK is pushing a million views for its third anniversary. :D

Congratulations!! You scored Post #1001 -- thank you for your contribution. ;)

This thread is alive and well; hundreds of DIYers all over the world are designing and building EconoWaves according to the precepts documented here. Its role as a reference resource is reflected in the view count.

[There are at least three Mini-Ewaves that'll be migrating into "prime time" here shortly.... ]

Its going to get worse...I've finally figured out how to put zma and fdr files into PCD. Now just to make my own such files from measurements....


Russellc

[dantheman]

Re: Flex Your PCD Mettle:

Hopefully the hating is a joke? Otherwise its odd.

Dan

[Skywave-Rider]

Re: Flex Your PCD Mettle:

Its going to get worse...I've finally figured out how to put zma and fdr files into PCD. Now just to make my own such files from measurements....


Russellc

OMG! :eek:
And I finally cut a hole with a router!
Doomsday approaches!

[Zilch]

Re: Flex Your PCD Mettle:

And I finally cut a hole with a router!

[Count yer remaining digits, now.... :p ]

[Russellc]

Re: Flex Your PCD Mettle:

OMG! :eek:
And I finally cut a hole with a router!
Doomsday approaches!

I have fiddle farted around with doing this for 2 or 3 years now, I'm with in purchasing the Zilch recomended mic pre and some cables away from measuring. I just wanted to play with zma and fdr files of others and get a little up to speed on PCD. Then the measuring learning curve begins, and how to make my own fdr and zma files. Since the B&C DE 250 and QSC guide has already been done, I just need to come up with measurments to make fdr and zma files for the JBL 2235H.

Then I should be able to tweek my existing crossover somewhat better. I have not bought a router yet, I'm not placing anymore projects in front of measuring.

Russellc

[DIYNut42]

Re: Flex Your PCD Mettle:

[There are at least three Mini-Ewaves that'll be migrating into "prime time" here shortly.... ]

By prime time do you mean this thread?

[Zilch]

Re: Flex Your PCD Mettle:

By prime time do you mean this thread?

Yes, using drivers anyone can purchase from PE, designs anyone can build, in Dayton prefinished cabs....

[DIYNut42]

Re: Flex Your PCD Mettle:

Cool. Looking forward to seeing, and reading about some new designs!

[dantheman]

Re: Flex Your PCD Mettle:

That will be sweet Zilch! I for one can't wait to see.

Dan

[penngray]

Re: Flex Your PCD Mettle:

Zilch, Im going to start making some baffle moldings but I have a couple of questions.

Assuming Im building them for your Econo waveguide deluxe build how far back do I need to mount the woofer?

Im building them assuming the woofer is rear mounted but I can go with any thickness on the baffle, Im going to use 1 1/4" round on the front.

I guess I could also move the woofer up closer to the waveguide but should I cut off the bottom lip of the waveguide or cut off the extra 1 1/4" of round over that exists on the top lip of the woofer mouth?

[Zilch]

Re: Flex Your PCD Mettle:

Hi, Penn,

Deluxe is just rear-mounted on a 3/4" baffle. Brandon ended up somewhat further back, 1.25", maybe, as I recall. The purpose is to minimize the forward-to-rear distance differential in the location of the driver acoustic centers using the 152i waveguide, and thus, the amount of phase compensation required in a passive crossover to make up for that.

With respect to center-to-center distance, we were both able to achieve usable -6dB forward vertical lobes in the +/- 15° range at ~1.4 kHz without doing anything heroic to minimize that, though I believe I did a bit better by maximally snugging woofer and waveguide together. Wayne Parham's rationale favoring asymmetric rectangular waveguides over round axi-symmetric ones clearly pays off in this respect.

At some point, the midline, presumably, it's necessary to define a transition between the waveguide mouth roundover and a woofer opening one. How well the two might be integrated or blended is largely an aesthetic matter, in my view, so long as the waveguide one remains intact. Jackgiff took a notch out of the flange, I'm starting the woofer roundover there, ultimately, and Brandon used some of the additional C/C distance for a more generous woofer roundover, which just plain looks nice in No Quarters. Your call on that one, but I would not cut into the waveguide profile any further than the limit of its front flange width.

http://techtalk.parts-express.com/showthread.php?p=1685505#post1685505

I look forward to seeing your design. You might want to try out some options in SketchUp and solicit opinions from the usual players by posting a bracket of them; there appears to be considerable range available within which to "work" this design element....

[penngray]

Re: Flex Your PCD Mettle:

Thanks Zilch, Good info. Wanting to use the 1 1/4" round over isn't going to help the CTC :(

My sketchup skills suck so its always tough for me to do graphics. I would rather just mock up some baffles and figure it out. Im going to try and build two different ones this weekend.

The front is easy compared to figuring out how to get the back of the waveguide molded then matching it to the front.

[Deward Hastings]

Re: Flex Your PCD Mettle:

[Count yer remaining digits, now.... :p ]

I started with octal on a PDP-10 . . . don't need thumbs to count to 12 . . . ;)

[Russellc]

Re: Flex Your PCD Mettle:

Regenerated FRDs from one axis, midpoint between the woofer and waveguide, @ 44" measuring distance.

[WHAT, no dancing banana...? :p ]

Zilch, is this still your protocal for obtaining FRD files for use in PCD?

Thanks,

russellc