Flex Your PCD Mettle:

[Zilch]

Re: Flex Your PCD Mettle:

Zilch, stupid question from filter network fool:
Presumably the on axis response rise at about 1500 Hz is easily dealt with in filter summation?
(Referring to system response plots you posted...or is all that out the window..are you starting from scratch?)

We're "refining" it at this point, based upon new measurements taken with the forward-mounted baffle. I've given it another try with the EconoWave crossover topology, moving the frequency up a bit:

[Skywave-Rider]

Re: Flex Your PCD Mettle:

Given recent data posted here regarding baffle edge diffraction, any speculation if offsetting a WG from the center line would be a good idea?

I know there's no room to do that in the current project in this thread. But if there was baffle space?

I understand that would make the forward lobes tilt.

[Zilch]

Re: Flex Your PCD Mettle:

Given recent data posted here regarding baffle edge diffraction, any speculation if offsetting a WG from the center line would be a good idea?

There's room to do a bit of that, and it doesn't take much to decorrelate the diffraction; I may do that on the next pair.

[For what it's worth, these sound quite delicious.... ]

[Zilch]

Directivity to 90°

Don't know how apparent it is, but at this 5° resolution, these plots are each a compilation of 37 response measurements; they're different ways of examining the same information.

Normalized:








Not normalized:






Done....

[dantheman]

Re: Flex Your PCD Mettle:

That normalized plot looks great Zilch. Can we see it not normalized? and can I ask why it took so many measurements? Was it to attach the low frequency on there or something? If so, what's the extra 1 measurement?

Thanks,

Dan

[Zilch]

Re: Flex Your PCD Mettle:

Hi, Dan.

It's the on-axis response plus 18 more each direction from there, out to 90°. If the baffle layout is symmetrical about the midline, as is the case here, the measurements left and right are assumed identical, but if there are horizontal offsets, all 37 must be taken.

For normalization, the reference angle, in this instance, on-axis or 0°, is corrected to flat, and the same correction factor applied at all other angles, so as to illustrate how the system would perform if the reference axis were EQ'd flat. In some instances, it may be desirable to design about an alternative reference axis, as, for example, is the case with Geddes loudspeakers, at +/- 22.5°.

Below are the other un-normalized plots for SpitWad. Toggle between them and the normalized versions to view benefit which might yet accrue to system performance from further smoothing the on-axis response, e.g.:

http://techtalk.parts-express.com/attachment.php?attachmentid=9285&d=1276535970

vs.

http://techtalk.parts-express.com/attachment.php?attachmentid=9260&d=1276458852

[dantheman]

Re: Flex Your PCD Mettle:

Looks good Zilch! It's funny, I rarely save the on axis graph b/c the old REW just didn't have many places available and the on axis never looks too different from the next over except for a hair of Geddes' Dip--why does that read sooo bad?:D New REW looks much better.

The normalized on axis does look better in general, but either way should make a great speaker. If you got the eq, use it.

Dan

[Zilch]

EconoWave Smaller Advent, aka "SpitWad":












Baffle insert dimensions:

3/4" thick, 18.625" x 10.125".
Waveguide cutout: 6.75" square, centered 4.5" down from top.
Woofer cutout: 9.0625" diameter, centered 5.3125" up from bottom.
Confirm - woofer and waveguide should "kiss," with ~0.5" space to baffle edge top and bottom.

[Zilch]

Re: Flex Your PCD Mettle:

Heh:

http://www.parts-express.com/eflyer/061710emailflyer.html?utm_source=Retail&utm_medium=Email_Newsletter&utm_content=Cannot+View&utm_campaign=email061710&AID=1457538&PID=3696791&SID=skim1010X497171

[rudyjakubin]

Re: Flex Your PCD Mettle:

Heh:

http://www.parts-express.com/eflyer/...kim1010X497171

A waveguide couples the high frequency driver to the listening space without the harmful distortion artifacts of marginally designed and implemented horn loading. It achieves this through the use of non-traditional geometries and lower expansion rates.

The resultant sound has less distortion, with an "open" characteristic not often associated with typical "pinched" or "honky" compression driver/horn combinations. Dayton Audio professional waveguides reveal all of the articulate, accurate sound reproduction that your HF drivers are capable of delivering, whether the application is live sound, critical studio monitoring, or demanding home audio playback.

Wondering if someone at PE built a pair to come up with this review????

[Zilch]

Re: Flex Your PCD Mettle:

Wondering if someone at PE built a pair to come up with this review????

Unlikely. Seems like the standard boilerplate verbiage....

[donprice]

Re: Flex Your PCD Mettle:

Any listening impressions? Or are you still working on the second one?

[Zilch]

Re: Flex Your PCD Mettle:

Any listening impressions? Or are you still working on the second one?

SpitWad?

Just added baffle insert dimensions above.

I'm building two crossovers right now.

Generally, if I build a pair of anything it's because I like 'em.

[SpitWad is sweet.... :D ]

[Skywave-Rider]

Re: Flex Your PCD Mettle:

Those spitwads now seem to be scarce on EBay, for some reason.

[Zilch]

Re: Flex Your PCD Mettle:

Those spitwads now seem to be scarce on EBay, for some reason.

Yeah, there were a half-dozen of them two weeks ago, as low as $5 apiece.

Did Zilch buy a bunch?

[NOOOooo.... :p ]