Flex Your PCD Mettle:

[donprice]

Re: Flex Your PCD Mettle:

Ordering my 12" driver for the Deltalite plan and came across this other Eminence driver - aside from weight is this not a better FR curve? Cost about the same.
http://www.parts-express.com/pdf/290-593s.pdf
http://www.parts-express.com/pdf/290-510s.pdf

And, I am aware that the baffle is 17" wide because that is how the Trap PA comes, but if one is building their own box is there an acoustic reason not to narrow that down to 15 and round over the edges? Sealed box, ~ 2cf.

The 2512/DE250/QSC152i combo has the crossover already worked up. Change the woofer and you need to change the crossover. I would stick with the 2512 if the cost difference isn't an issue.

Changing the baffle width from 17" to 15" will have some effect on the system response. Will it be enough to matter? I don't know. I doubt it would be huge.

[gmannel]

Re: Flex Your PCD Mettle:

Ordering my 12" driver for the Deltalite plan and came across this other Eminence driver - aside from weight is this not a better FR curve? Cost about the same.
http://www.parts-express.com/pdf/290-593s.pdf
http://www.parts-express.com/pdf/290-510s.pdf

And, I am aware that the baffle is 17" wide because that is how the Trap PA comes, but if one is building their own box is there an acoustic reason not to narrow that down to 15 and round over the edges? Sealed box, ~ 2cf.

[Mayhem13]

Re: Flex Your PCD Mettle:

Mine are in 2 cuft sealed boxes and extend easily flat to 80hz in room with no need for a high pass filter. I only low pass the bass bins for a seedless match......Geddes does the same but instead uses band pass subs for an all acoustic low pass approach.

[gmannel]

Re: Flex Your PCD Mettle:

In a larger box, and the Deltalite 2512 concept, is there any place for a 12" passive radiator, or would that mess w/ directivity?

[gmannel]

Re: Flex Your PCD Mettle:

OK - thanks - I won't waste time and $ on it then. Will go w/ the Deltalite 2512 way! Is the only reason to use the Kappalite instead to pick up more lowend? Is the Deltalite idea to give better mid-lows? Since I have the THT sub, I just want the best sound for the center channel, whether that be the Kappa or Delta.
Will be building my own cab, so is there any downside to building as a 2.27 cf as the driver actually specs to as opposed to the 1.5 that the Trap PA prebuilt is?
As long as I maintain the proper driver spacing and the baffle width?
Is the baffle width actually 17" outside width(including the joints w/ the side panels) on the pre-cut PA box?
I was planning to flush mount the baffle and round-over the edges if acoustically a good idea.
So I was thinking a 2 cf trap shaped sealed box, stuffed to make it "seem" 2.27 cf, w/ the drivers near the top, properly CTC spaced. Any problems?

[dtruck]

Re: Flex Your PCD Mettle:

A line array cannot achieve the constant directivity and controlled dispersion that this project aims for without being pretty different from this project.

[gmannel]

Re: Flex Your PCD Mettle:

Yes, I had settled on the Deltalite 2512, but then I thought it would be fun to see if an LA would work w/ this awesome QSC/250 combo, esp since my LR are 1-way full range LAs, and w/ the sub, and bringing the WG up to a good height.
The 2512 models to a 2.27cf box, so if I went that route I could gain some height there, esp w/ a trap shaped box.
If I wanted to try the EconoWave LA as a learning experience, could you guys help me properly measure the result so I can see if it worked, beyond just hearing it?
Thought the array could be 8 of these which match my MCLA LRs, albeit 6" vs 4" - http://www.parts-express.com/pe/show...number=295-342

[donprice]

Re: Flex Your PCD Mettle:

Would this be a bad combo for lobing or other issues?
A line array of 4 of these:http://www.parts-express.com/pe/show...number=290-507,
or 6 of these:http://www.parts-express.com/pe/show...number=290-542,
w/ the QSC/250 combo on top, as a center ch behind an AT screen?
xover miniDSP, bass covered by LR line arrays and TubaHT sub.

Why not stick with something simple like a single Deltalite 2510 or 2512?

An MTM with a pair the Delta 8 and a 18Sound XD125 looks appealing...at least to my untrained eye.

[donprice]

Re: Flex Your PCD Mettle:

FR txt file attached.

Yea, I noticed it was inverted...

[dtruck]

Re: Flex Your PCD Mettle:

Check your alignment of the driver to the throat of the waveguide, might be off-center. I don't know why yours doesn't show the dip at 1200Hz, though. Does it change if you move the time window out?

No, I do start to get a ripple as I move the gate out, but it does not line up with the ~1200Hz dip. I have messed with the throat a little, and it seems to only effect much higher frequencies, but I'll be investigating more today.

Here's mine. DE250 on QSC waveguide measured at ~42" at bottom of waveguide/top of woofer. I tried to match your gating value. I believe this was collected with the speaker in my entertainment center which has a baffle edge ~1-1.5 inches tall.

Why is your impulse response squiggly?

Thanks for posting it! Any chance you saved it as an frd/txt file? Your impulse is also squiggly (and inverted, by the way), as is Zilch's. Why mine is a little more uniformly squiggly, I do not know . Could be the lack of a protection cap on mine? I don't have anything big enough to use for that, although I guess I could try to create one from some electrolytics wired up in series-parallel with a film bypass... maybe I'll try that now.

[gmannel]

Re: Flex Your PCD Mettle:

Or 8 of these:http://www.parts-express.com/pe/show...number=295-342?

My LR MCLAs are the 4" version of this same driver so the match would be natural.

So any downside to a EconoWave LAY

[gmannel]

Re: Flex Your PCD Mettle:

Would this be a bad combo for lobing or other issues?
A line array of 4 of these:http://www.parts-express.com/pe/show...number=290-507,
or 6 of these:http://www.parts-express.com/pe/show...number=290-542,
w/ the QSC/250 combo on top, as a center ch behind an AT screen?
xover miniDSP, bass covered by LR line arrays and TubaHT sub.

[bwaslo]

Re: Flex Your PCD Mettle:

Check your alignment of the driver to the throat of the waveguide, might be off-center.

I don't know why yours doesn't show the dip at 1200Hz, though. Does it change if you move the time window out?

[donprice]

Re: Flex Your PCD Mettle:

Here's mine. DE250 on QSC waveguide measured at ~42" at bottom of waveguide/top of woofer. I tried to match your gating value. I believe this was collected with the speaker in my entertainment center which has a baffle edge ~1-1.5 inches tall.

Why is your impulse response squiggly?

[Pete Schumacher]

Re: Flex Your PCD Mettle:

Does anybody have any thoughts on this measurement (DE250 on the QSC waveguide)? Mine is red, Zilch's is green. As you can see, there is a significant difference in the crossover region (note the 2dB/line scale)...



Brandon's measurement seems to split the difference, partly:


By the way, somebody should really change the png and gif requirements to no size limit and 30-100kB. Uploading graphs as jpg files is worse quality and takes 5-10 times as much space, but it's the only option right now.

Zilch did not have the WG on a flush baffle, but on the trapezoid knock down. There are large protruding edges on the trap enclosure, which have a detrimental effect on diffraction.