Zilch's AK Design Collaborative - Econowave Speaker
- Thread starter Zilch
- Start date
bugs762
Active Member
How about the L-pad?
similost
Rockin and Rollin....
I don't understand how they lose money. They charged me for shipping, which I would expect to have to do...
ROSSO
Active Member
Amen. Selling sub $10 plastic waveguides by phone-order has to be a loosing proposition. Labor per phone call alone would break the bank. I don't understand why they can automate the web-based tent sale and not the waveguides? That would at least take out the labor of the archaic phone order system.
Honing In AR4x:
Before:
After:
Making the lowpass 3rd order using 1.0 mH in series with the woofer moved the forward axis down to the waveguide axis at 44" mic distance.
Update:
Vertical polar map after a couple more tweaks:
Links for tabbing between the three maps:
http://www.audiokarma.org/forums/attachment.php?attachmentid=186307&d=1261789836
http://www.audiokarma.org/forums/attachment.php?attachmentid=187088&stc=1&d=1262223987
http://www.audiokarma.org/forums/attachment.php?attachmentid=187156&stc=1&d=1262247645
Crossover:
Performance of the pair:
On forward vertical axis. They're 32" apart, so arctan 16/44 = 19.98° horizontal, hence the tilted power response.
Bonus:
Vertical polar map of the pair.
And finally, toed-in:
Both -5 dB (shoulda been -6).
[Yeah, I got the color sequence reversed, too. Check the time stamps....
]
Before:
After:
Making the lowpass 3rd order using 1.0 mH in series with the woofer moved the forward axis down to the waveguide axis at 44" mic distance.
Update:
Vertical polar map after a couple more tweaks:
Links for tabbing between the three maps:
http://www.audiokarma.org/forums/attachment.php?attachmentid=186307&d=1261789836
http://www.audiokarma.org/forums/attachment.php?attachmentid=187088&stc=1&d=1262223987
http://www.audiokarma.org/forums/attachment.php?attachmentid=187156&stc=1&d=1262247645
Crossover:
Performance of the pair:
On forward vertical axis. They're 32" apart, so arctan 16/44 = 19.98° horizontal, hence the tilted power response.
Bonus:
Vertical polar map of the pair.
And finally, toed-in:
Both -5 dB (shoulda been -6).
[Yeah, I got the color sequence reversed, too. Check the time stamps....
]Attachments
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1scienceguy
AK Member and E-waver #88
Good evening!
So the project parts are ordered and I have prepped the HD77 boxes. I plan on locating the waveguides high in the box with the 12" Rat-Shack woofers (40-1034) right underneath. There is a lack of data on these woofers and some think that they might have a high QTs factor resulting in the need for a large box (current cubic feet =1.855). Is there any need for a port or any mods to this box to accommodate these woofers? I'm new to this area so please help me as much as you can. Thanks
So the project parts are ordered and I have prepped the HD77 boxes. I plan on locating the waveguides high in the box with the 12" Rat-Shack woofers (40-1034) right underneath. There is a lack of data on these woofers and some think that they might have a high QTs factor resulting in the need for a large box (current cubic feet =1.855). Is there any need for a port or any mods to this box to accommodate these woofers? I'm new to this area so please help me as much as you can. Thanks
You'd have to measure the T/S parameters of those woofers to target an optimum box alignment, but generally, high Q woofers with low resonant frequencies are well suited to small closed boxes, 1.86 cuft. being "smallish" in this context.... :thmbsp:
skywave-rider
Slumming in Akihabara
Help me...how are u getting better vertical directivity in the woofer response above 200Hz by changing the low pass to 3rd order?
And why does the high end vertical response look more tidy as well? I am assuming it's because the measurement axis is now lower, and better aligned to the 8x8s 50º vertical pattern. And how the hell did you figure out how to shift the phase to do this????
And why does the high end vertical response look more tidy as well? I am assuming it's because the measurement axis is now lower, and better aligned to the 8x8s 50º vertical pattern. And how the hell did you figure out how to shift the phase to do this????
Before:
After:
Making the lowpass 3rd order using 1.0 mH in series with the woofer moved the forward axis down to the waveguide axis at 44" mic distance.
Links for tabbing between them:
http://www.audiokarma.org/forums/attachment.php?attachmentid=186307&d=1261789836
http://www.audiokarma.org/forums/attachment.php?attachmentid=187088&stc=1&d=1262223987
Hang onta yer mic stand; I just updated:
http://www.audiokarma.org/forums/showthread.php?p=3316259#post3316259
See the legends; I've progressively increased R1 to provide more HF comp and level the response. C1 also increased to 6.8 uF in the latest version, filling in the hole left by the 3rd order lowpass.
The JBL elves told me:
http://www.jblproservice.com/pdf/AE Series Compact Models/AC1895-WH.pdf
See their curves with this combo here:
http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=1080
I can raise and lower the forward axis by adjusting the value of the 3rd pole inductor. That also changes the response a bit, so each time, I have to find the forward axis to make the requisite adjustments. Right now, it's at waveguide axis +2", and I'd like it lower than that, actually, between the midpoint of the drivers and the WG axis. Maybe I'll tweak a bit more tomorrow, but I think I'm gonna put this exercise away for now; I've got something else cooking in the Trap cabs you'll like....
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1scienceguy
AK Member and E-waver #88
So if I am understanding you correctly (old age is setting in), at first glance, these woofers will like a small, sealed box?
I do not have any way to measure the T/S parameters but some comparable Rat Shack woofers have ~90 sensitivity and high QTS.
And just for my own brain, a port is not going to add any musical qualities to the build?
Thanks guys and gals for the help during this "fun" learning experience.
donprice
Wound up workin' at a gas station....
Some discussion regarding the hunt for the same info...you may have already found this...
http://db.audioasylum.com/cgi/m.mpl?forum=vintage&n=62732&highlight=40-1034
In theory, all you can do (without spending $100 on a woofer tester or finding a buddy that did) is plug the assumed values into a modeling program with the known cabinet volume. Run a sealed box model, then run a ported box model. I don't know enough to guess which one is "better" particularly when much of the model input is a SWAG.
In reality, build the sealed box and listen to it. Then cut a port into the second box and start experimenting. Keep the design you like best. 2-3" cardboard tube is cheap...cut the port where you can patch it if you don't use it.
Just build it and listen. Good luck!
Rygen
I can break any motor.
Been following this thread closely, especially after I received my x-over board from Zilch months ago for my Valencia cabs. I finally got of my ass and ordered all the remaining parts today, so hopefully in the weeks to come I will have these put together.
Can't wait!
Can't wait!
Ok guys I caught the e-wave bug, but before the parts ordering process begins I want to be sure my crossover is properly picked. I seen on the project summary a crossover for a <95db woofer and one for a JBL LE14A woofer. Which crossover is best suited to be use for my newly acquired JBL 2235H's. Also are there any sonic differences between the JBL waveguide and the Pyle Pro PH612 waveguide? As always Thanks, Scott
skywave-rider
Slumming in Akihabara
Looks like a great room curve. Very precise finding the center, Zilch.
You've fixed the midrange problem which always bothered me about those in the setup I had them in. May revisit 8x8 now that you've done all the work...LOL.
Are you showing vertical down from forward axis, or is that up and down in the latest?
http://www.audiokarma.org/forums/attachment.php?attachmentid=187156&stc=1&d=1262247645
Seems like just down.
Watching for the KDT news!
With one exception early on in the QSC studies, I've kept the same protocol throughout, measurements up and down from the waveguide axis in 3" mic height increments at 44" from the baffle. The color sequences are:
Waveguide axis = Red
Up = Orange, Yellow, Gray, Aqua
Down = Green, Blue, Violet, Cyan
So, that's 12" total each direction, and we're looking at a "window" of the vertical dispersion about the waveguide axis which is +/- arctan 12/44 = 15.26°, or 30.52° total.
I'll refine that, as you suggest, so it's linear degrees in the future, but at these extremes in that curve, you can see the lower null beginning to manifest as cyan, and the upper as aqua (light cyan), the lower being more prominent, in part because the forward axis is 2" above waveguide center in this example. The Zilch effect is also clearly evident: the influence of the lower null occurs above the crossover frequency as determined by the inverse null, whereas the upper null affects the response below crossover, the two converging in the crossover region at their maxima.
Bottom line of all of it is that when we're doing this, the location of the forward axis matters, and we've got to choose either a reference axis (waveguide, midpoint between drivers, etc.,) or a specific design axis at which to optimize the response. I'm sure Wayne told us that, several times, probably, but it wasn't until the QSC waveguide was so difficult to work with that the message clicked.... :thmbsp:
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LE14A and 2235H are similar in many respects. I'd have to try both lowpass filters to make that determination, but you can also do it by purchasing components for both if you want to see if any difference is apparent.
There are differences between the JBL and Pyle waveguides in detail, but nothing audible so long as you use the "approved" drivers on them. As Augerpro and I demonstrated in measurements, the Pyle gets messy in the VHF using DE250 on Selenium throat adapters, for example. Stick with the program, and the Pyle is fine for use in EconoWaving.