Zilch's AK Design Collaborative - Econowave Speaker

[Zilch]

So the DE 250 is OK with the JBL wave guide? (with the exception of the 4K "needs work" area).

Indeed, using the Selenium ADM-25 throat adapter, it is the best of the lot, much as I believe 900ss and I earlier determined.

The waveguides look so similar, any speculation as to differences or causes, or is this to do with the adapter?

Upon close examination, there are differences in the throat of the Pyle waveguide. They don't seem to matter with the E'Wave standard thread-on Selenium D220Ti drivers, tho.

Does the bolt on Selenium With the adm-25 adapter and JBL waveguide exibit this dip also, or is it specific to the DE250?

See the Gry/Blk curve. That's the D220Ti bolt-on with Selenium ADM-25 throat adapter on the two different waveguides.

As to the 4K area hump, would lowering the LF crossover help this any, sort of like the LE14A 900 hz LF crossover did for that driver?

Possibly, but it's the highpass filter that needs rework. It'd be great if some alternate throat adapter such as P-Audio PC-20 worked, but from experience to date, I am not hopeful. These results confirm our earlier determinations that a bolt-on driver with a throat adapter is not equivalent to a thread-on, in detail.

How big of a deal is this? Not as big as the measurements show, probably, when it comes down to audibility; the notches are high-Q and notches, not peaks, which listening research indicates are more problematic. That doesn't mean that we should ignore or dismiss this, however, if the objective is to do the best we are able.

At the end of the session (see the timestamp), I reassembled the DE-250/ADM-25/JBL PT combination and remeasured to confirm that the measurement was not an anomaly of some sort. Here is the result, presented in more typical scale:

Compare to our earlier findings from several months ago back on Page 310 here:

http://www.audiokarma.org/forums/showthread.php?p=2549189#post2549189

 

[Russellc]

The first chart you show with the green and red plots, if I am correct are:

Red= B&C DE 250 with adapter and pyle wave guide,

Green= B&C DE 250 with adapter and JBL wave guide,

Right? I dont know why these graphs give me so much trouble!

Thanks again,

Russellc

 

[Zilch]

The first chart you show with the green and red plots, if I am correct are:

Red= B&C DE 250 with adapter and pyle wave guide,

Green= B&C DE 250 with adapter and JBL wave guide,

Right? I dont know why these graphs give me so much trouble!

Yes, I merely swapped the waveguides, and you can see the result. In the higher frequencies, the green is the best of the lot, and I re-measured at the end of the session to confirm this finding.... :yes:

 

[jackgiff]

Yeah, But how does it sound?

We all know these measurements just don't mean anything, compared to how they sound.

When will all of us wake up?







(Tee Hee Hee. )
Just kidding, of course. Thanks to Zilch for all the tireless measuring he does for all of us. Keeps a lot of us out of trouble.

 

[Zilch]

HI, Jack!

I thought we might be in trouble, 'til I found that both waveguides measure the same with our standard thread-on D220Ti.

I hope everyone's getting that none of this is slam-dunk swappable without verification via measurements.... :nono:

 

[GordonW]

OK. So, as long as we use the screw-on D220, there's no anomaly to worry about.

Was concerned a little bit, after speed-reading the last few posts.

Back to my regularly scheduled sawdust, solder smoke and metal filings making, I guess...

Regards,
Gordon.

 

[Zilch]

Back to my regularly scheduled sawdust, solder smoke and metal filings making, I guess...

Yup, carry on makin' cool stuff, Gordon! :thmbsp:

 

[jackgiff]

I was a bit stunned when this all came to light. I tried the D210Ti and D220Ti on both the JBL and Pyle waveguides, and saw absolutely no difference. I even told someone that I couldn't believe that an adapter to convert a bolt on driver to screw on mounting would make any difference.

Going from screw on to bolt on adds extra length to the throat, but bolt on to screw on shouldn't. If a screw on driver works, a bolt on should work with an adapter. Who Knew?

Good thing we limited our EconoWave formula to the Selenium D220Ti and D210Ti.

But it is a good example that not everything is "plug and play." I am a firm believer in measuring and listening. It is great to back up the good sounds you are hearing with good measurements. Seems to keep everything "honest."

 

[Zilch]

I'm probably more hard-nosed about this than I have to be, but I've been burnt more than enough times to know to proceed with caution:

Unless/until otherwise determined, best advice is to stick with the program.... :yes:

 

[jrock7]

hello zilch, could you tell me what is the dept of the 6 x 6 Jbl waveguide horn. And which would be better to use - the 6X6 or the 12x6 waveguide with a 12 inch woofer?

 

[jrock7]

sorry I meant Depth of 6x6 jbl waveguide

 

[Zilch]

hello zilch, could you tell me what is the dept of the 6 x 6 Jbl waveguide horn. And which would be better to use - the 6X6 or the 12x6 waveguide with a 12 inch woofer?

From front of baffle to rear of Selenium D220Ti driver:

6" X 6" = 4"
8" X 8" = 7.75"
12" X 6.5" = 6.25"

Any of them will work with a 12" woofer, but the 12" would be preferred.... :yes:

 

[Bauhausler]

Just to confuse things further

Because we're talking about swapping parts around. I've found that both of my JBL 2414H (threaded) drivers fits well on the JBL 6" X 6" waveguide, but one will not mate with any of my 4 Pyle PH612s. Something is too tight. All of my Selenium drivers fit on everything so I suspect the OD of the threads on one 2414h is too 'full'. The solution would be to disassemble the driver and chase the threads with a die. I already touched up a few small marks with a thread file but that made no difference. I'll do that if it really looks like the 2414H/PH612 combination is worth hearing. I guess I should take a micrometer to the threads and just measure them.

 

[Zilch]

I just turned CLIO off for the night; I'll measure the combination for you tomorrow to assess what will be required to have it work.... :yes:

 

[GordonW]

I was a bit stunned when this all came to light. I tried the D210Ti and D220Ti on both the JBL and Pyle waveguides, and saw absolutely no difference. I even told someone that I couldn't believe that an adapter to convert a bolt on driver to screw on mounting would make any difference.

This does lead me to a little hope, for a problem situation I had. Using a screw-on D210Ti on the back of an Eminence Beta 10CX (coax) led to a big dip at around 6KHz. Maybe the slightly different geometry of the bolt-on driver and the adapter might change that a bit? I know it's just luck if it happens, but it's at least another option I can easily try, with stuff I have around...

Sometimes, it's just about either creating or breaking up a standing wave or cancellation null or something similar, I guess...

Regards,
Gordon.

 

[Russellc]

"Possibly, but it's the highpass filter that needs rework. It'd be great if some alternate throat adapter such as P-Audio PC-20 worked, but from experience to date, I am not hopeful. These results confirm our earlier determinations that a bolt-on driver with a throat adapter is not equivalent to a thread-on, in detail."

Zilch, do you think that's why Wayne uses a 3pole filter on the HF when using the DE 250, or would that not really be the determining factor. It seems to me at first blush that a steeper slope may help, of course I'm sure I am failing to take a lot into account beside slope of the crossover. ( speaking of the 4K or there abouts response abnormality)

Russellc

How in the heck do you put those nice little gray quotes in your posts?

 

[Zilch]

Zilch, do you think that's why Wayne uses a 3pole filter on the HF when using the DE 250, or would that not really be the determining factor. It seems to me at first blush that a steeper slope may help, of course I'm sure I am failing to take a lot into account beside slope of the crossover. ( speaking of the 4K or there abouts response abnormality)

Perhaps, but recognize that Wayne is not dealing with the specific issues created by throat adapters. Look at both the Selenium and DE250 with throat adapters vs. the thread-on Selenium, and you'll see the commonality of what's occurring; that's what needs to be addressed.... :yes:

 

[Bauhausler]

The latest Ewaved Large Advents are up and running.

Dennis Nagle came over today for a visit and to pick up a turntable. In an hour I rushed through finishing the second speaker, which needed only sanding out and assembling. We listened to the pair, fresh and before break-in. I'm hoping that a few hours with the bottom octaves boosted to get some cone motion will bring up the sensitivity of the woofers. I'm running the lpad for the top end at about 50%, which is lower than I recall for the Utility pair that I built.
THis pair turned out well. Everything pretty much worked as planned, including the direct wired Masonite panel crossovers, the modification of the cabinet's plastic rims, the paint on the front and back, the grille kits from P-E and the indexed 'fader' knobs on the Lpads.
One thing I wish I had been able to do is strip off the dark varnish from the cabinets and expose the contrast of the grain. I'm big on nice wood. It's risky, though, as you don't know where the veneer is feathered thin and a little more sanding will go through. So I just surface sanded and waxed them.
On Monday these will go to my friend Kevin for comparison with the JBL Barons (C38, D130 & 075) that I sold him. I think he'll be amazed by how much is in the bottom 2 octaves that these speakers have over the D130s. I'm guessing the Advents won't be coming home.

 

[djnagle]

They sound great B. I was really impressed at how low they go with those lighter surrounds. The imaging was great off axis and the horn blends in seamlessly with the woof. I also really like the very sheer grill cloth. It is absolutly transparent, sonically, as well. That is a great combo.....well done.

After leaving your house I started to think that it is high time I got going on the eWave-American Monitor project I have sitting around.

 

[testwork]

A friend is interested in having me build them an eWave speaker system. They have 12' ceilings. The front wall has a hallway on both sides. So there is absolutely no where to place speakers on the left or right of the room. And he'll never be able to have a center speaker either, due fireplace and a built-in taking up the entire lower portion of the front wall.

Yes, buying the house was his Wife's idea.

So the only realistic place to have the speakers is high on the walls, next to the ceiling. The room is 12' tall by 13' wide.
I suggested the eWave because this speaker sounds good, no matter where you're sitting in the room.

His wife will want speakers as small as possible.

I was thinking of the JBL 8x8 waveguides matched with Dayton 10" classic drivers. I'd have them mounted side by side, so the speaker enclosure is short & wide, rather than tall and narrow. Or something like 11" tall, 19" wide. Would that work?
Would it require re-doing the eWave crossover?