ISO Mid-Bass for Econo-Waveguide

[Saurav]

That looks even deeper than the XT1086. I'll be following your crossover design with interest, since that's where I gave up with my project

[augerpro]

I'll be using 12" woofers so I don't think I'll have your AC offset problem. It is deeper than I expected though.

[NEO Dan]

My JBL and PartsExpress orders arrived





So far no complaints, but no judgments either. After putting some power to them I think a TL might be be a neat option as the driver did maintain a clean sounding bass at high level for not having a box to keep it in check. An OB would be another interesting option...

[augerpro]

Cool. Are you using the crossover in that econewave thread at audiocircle? BTW how deep is the horn? The PE one was deeper than I expected.

[NEO Dan]

It's about 3 5/8" from the face to the throat.

It appears that the woofer is efficient enough that the HE version of the x-over will be required

I found my Mic this morning, check out the impov....



This is averaged Pink Noise, L-Pad at WOT



and I got a little out of hand with the SketchUp, thinking of the Frugal Horns. I'd call it the Big Bang Chang 8O

[NEO Dan]

but why stop when you are having fun...

[augerpro]

Dan I just bought a pair of those 12PR300's so no need to send yours for testing.

[NEO Dan]

Sweet....
oh... my bad, did I say that out loud.... :lol:

Here is a little info on a low cost bolt on CD + horn combo look above my Frugal horn concept drawing...

[NEO Dan]

I went back and measured some more, this time the drivers were supported by 12"³ corner fills. Each driver was measured individually with the crossover in place. REW was set to average 4 sweeps.



1/12th octave smoothing applied



Even with the L-Pad at WOT the 12PR300 kills the D220Ti

[augerpro]

You're saying the woofer has an Lpad and it still higher sensitivity than the CD? That doesn't sound right. Are you using those measurements to calculate the XO? An unbaffled woofer measured near-ish field isn't going to be anywhere close to accurate. I know that's seems obvious, just thought I'd mention since I don't understand your measurement setup.

[Saurav]

I think he's referring to the Lpad in the "econo-wave crossover":

http://audiokarma.org/forums/showthread.php?p=1856214#post1856214

It's basically the CD EQ, and a high-pass, by the looks of it. There are suggested filter networks for woofers.

[Dennis H]

That sensitivity match doesn't look so bad. When you put them in a box and measure at a bigger distance, the baffle step will show up and you'll end up needing to knock a few dB off the higher woofer frequencies to compensate.

[NEO Dan]

Thanks for the input guys

Here is the crossover I am using





I had to deviate from the BOM on the L2 pn 266-552 it was OOS, the DCR on that part is .22 Ω

I also deviated on L1 from the stock 20awg Jantzen pn 255-040 has a DCR of .53 Ω

I took a few more passes at it this morning
RAW



With and without x-over



All this has me wanting to lower the HP to ~ 2.4 kHz from "3 kHz" electrical

This would be my first crossover, and will be my first use of SoundEasy if I can find the CD 8O

I should have my WT2 back this week, once I've measured I'll start on the box.

[Saurav]

IMO, you need to build the box, get the drivers in there, measure that, and then design the crossover from those measurements. The 'stock' crossover will get you in the ballpark, but it's not optimized for your drivers, there is no way it can be. It'll probably be a good starting point.

This is assuming you care about implementing a crossover that tries to properly match the phase between the drivers. You may or may not care about that. Many people are happy tweaking crossovers by ear and never taking any measurements. But (again, IMO), if you put some effort into the crossover, the results will be well worth it.

[NEO Dan]

I can't wait to get my gear back so I can get started...

[NEO Dan]

So here are some TS params...



Although both drivers went through lengthy suspension break-in, the second driver has about 1/3 less play time on it. That was from me beating on the first one a bit with music. Test conditions were ~80°F/80%H

[NEO Dan]

Find of the day...
~8" square 90° x 50° coverage PT™ Waveguide, also available in 120° x 60° coverage.

[augerpro]

Found the econo wave type profile in bigger format to enable pattern control lower: 338781-001 from the AC2212/95. $138 though.

[NEO Dan]

The AC2212/95 is the 3388001-001:

http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=665

http://www.jblproservice.com/pdf/AE%20Series/AC2212,95-WH.pdf

[NEO Dan]

Found the econo wave type profile in bigger format to enable pattern control lower: 338781-001 from the AC2212/95. $138 though.

The AM6212/95 has the 338781-001. It is a BIG BAD A$$ WG

http://www.jblproservice.com/pdf/AE%20Series/AM6212,95-WH.pdf

http://www.jblpro.com/catalog/support/getfile.aspx?doctype=3&docid=656

I'm finding the parts lists are not real accurate....

[NEO Dan]

If you look at the line for the 338781-001 you will notice that it is listed as going into a AM6212/64 and the AC2212/95... Some NON-Engineering type must compile the list

[augerpro]

Well assuming the tech sheet you posted is correct, it is indeed the 338800-001 I like. If people really like the econowave one, I would say they should get this instead due to it's pattern control to lower frequency.

[augerpro]

So is the 338800-001 actually the so called econowave? Maybe it's not as big as I thought...

[ThomasW]

The so called Econo 12" W x 6.5" H, JBL part #338800-001 is a $9.90 unit. It appears to be identical to the Pyle Pro CD horn you got from PE, only the PE one has the nice metal threads.

[augerpro]

Well bullocks...I was hoping to have found a bigger version. The econo directivity has pretty much gone to hell by 2khz, which implies a considerably higher crossover point.

[ThomasW]

Yeap that's why I haven't bothered doing anything with the ones I have.

The more WG's/horns I get in to audition the more I go back to the DDS-ENG-1 as the only thing that XO's reasonably low and sounds 'natural'.

That said I haven't played with the 10"/12" circular units from PE

[kevinp.]

Yeap that's why I haven't bothered doing anything with the ones I have.

The more WG's/horns I get in to audition the more I go back to the DDS-ENG-1 as the only thing that XO's reasonably low and sounds 'natural'.

That said I haven't played with the 10"/12" circular units from PE

I wish you would; I'd love to hear a qualified opinion on them...

[Saurav]

What about the XT1086? IIRC from my measurements, that maintained pattern control quite a bit lower than 2kHz.

[NEO Dan]

What would be the desired cutoff for DI/frequency?

[augerpro]

Saurav you know that might be the real winner of all these. Not a budget horn, but not bad either. Do you still have one? I'd love it to include it in testing.

Dan I don't know what would be a good frequency. Just looking at the response I would aim for 3khz LR4, but that's pretty far apart for the CTC distance I would imagine. You''l just have to balance directivity versus CTC and find a compromise. There may not be a real good one...

[NEO Dan]

What about the XT1086? IIRC from my measurements, that maintained pattern control quite a bit lower than 2kHz.

Measurements

[Saurav]

Saurav you know that might be the real winner of all these. Not a budget horn, but not bad either. Do you still have one? I'd love it to include it in testing.

Nope, sold them to pay for the DE10/ME10 replacement. It's 90 bucks from Loudspeakers Plus:

http://www.loudspeakersplus.com/product.asp?specific=jmmmfrlnq

Seems within the price range of some other stuff you've bought recently to investigate

[NEO Dan]

Is the XT1086 the one with the diffraction slot on one axis? I thought that was bad?

That RCF H100 has the same thing going on...

I'm wanting to stay to the WG side of of things as much as possible...

[Saurav]

Yes, it is. IMO, 'bad' is a sliding scale with conflicting requirements By Geddes' definition, it is not a waveguide. However, it is potentially better than some of the available alternatives. With the right woofer, it'll let you move your XO point an octave lower, which would certainly be desirable. Pick your poison.

[augerpro]

The H100 and 1086 have diffraction slots? I can't really see one.

BTW dan, what is you CTC distance? FRD consortium has a assymetric radiation simulator that can help you visually predict lobing vertically and horizontally.

[NEO Dan]

Physically they will be within 1/16th", but that can't be used for calculations as every CD/WG combo has it's own "distance" right?

[Saurav]

The 1086 have diffraction slots? I can't really see one.

Don't know about the H100. The 1086 has a diffraction slot, if I understand what one is. It's difficult to see in photos. John Janowitz took some good pictures:

https://www.htguide.com/forum/showpost.php?p=404095&postcount=90

The horn flare is smooth in the vertical axis, but has a discontinuity on the horizontal plane. On DIYAudio someone posted pictures of a foam mold made from the 1086, the break in the curve is easier to see that way. For some reason I thought you were the one who'd posted those photos

Heh... I was right, it was you, unless there's a different augerpro on that forum

https://www.diyaudio.com/forums/showthread.php?postid=1517026#post1517026

[AJINFLA]

Physically they will be within 1/16th", but that can't be used for calculations as every CD/WG combo has it's own "distance" right?

Dan, I'm pretty sure Brandon is referring to acoustic center to center distance.
Hence the lobes.

cheers,

AJ

[augerpro]

Saurav I forgot about that! Actually it was Noah Katz that made the foam plug, but i was thinking it was a different waveguide for some reason. Well all things considered the 1086 is looking more promising even with that abrupt transition. It does everything else right, or at least leagues better than all the cheaper options and foam should be able to minimize it's one fault. The only other that looks real promising is the JBL WG from the MRX series. I'm trying to order a pair now.

AJ exactly right.

In discussion with Dr. Geddes now over my test protocol before he decides to send a waveguide.

[NEO Dan]

I would love to hear about Geddes testing protocol. Been wondering about that for some time. I was just contemplating building a jig with stops to measure polars. You got any ideas?

[augerpro]

When using my big baffle I'll just be dropping a plumb, then marking an arc for the mic.

For speakers I'm making a jack stand of sorts with a lazy susan top (with angles marked off) and it will be extendable. I'll post a pic when I'm done.

[NEO Dan]

I snagged a pair of JBL 2408H's today

And I finally found the JBL equivalent to the BMS 4540ND it's the H. I knew it existed...

The MRX WG's are coming from China, so there's gonna be a bit of a wait on them.

[NEO Dan]

Boredom strikes

[CraigJ]

Here is QuickSilver's sketch https://www.htguide.com/forum/attach...chmentid=14137 from one of your earlier threads. Pretty cool I"d say.

Craig

[NEO Dan]

Craig,
that's very nice, don't remember it though. Where was that again? I wish I had something better than SketchUp.