Flex Your PCD Mettle:

[dantheman]

Re: Flex Your PCD Mettle:

1.6 kHz isn't low enough even with 24dB/octave filters unless you are not too particular about the final result.

Here's what the filter looks like:

add this:

get this:


Notch that woofer and get this:

get this:


I did them myself.

A wider polar response on the tweeter would make that more doable.

Dan

[donprice]

Re: Flex Your PCD Mettle:

1.6 kHz isn't low enough even with 24dB/octave filters unless you are not too particular about the final result.

I did them myself.

A wider polar response on the tweeter would make that more doable.

Dan

I'm a little confused. Are you saying the problem the problem with the woofer is in the HF section? Or more specifically, that the woofer becomes overly directional (got to be better terminology) past 1kHz and the solution is for the HF section to reach down and fix it? I think I just answered my question.

Is the problem the Delta Pro 12 in particular or beaming of 12" drivers in general? I'm really curious since my brother has a pair (I think) of the Delta Pro 12 that may end up getting eWaved.

By the way, were the curves based on measurements or modeling or a little of both?

[dantheman]

Re: Flex Your PCD Mettle:

Those are all real measurements, no simulation. The notch was made with left over parts so it isn't perfected, just as best I could do with what I had on hand. That woofer isn't overly directional or anything, it's just that its break up is too violent to cross over very close to it. So the the problem with the woofer is its break up. You might be able to damp the heck out of the cone and get it to be more useful. After numerous rounds of damping got this:

but I never did the long term tests to see if it would remain stable for some time. You can see that the damping also brought the frequency of the onset of break up down as well (lowered the Q) so there's just no perfect way to make it happen, just different types/degrees of compromise. I would think the damped cone would be the better solution. You can see that the real dispersion is right about as piston simulation would predict, but the fact that its break up is so violent it's causing all sorts of deviation. From what I've measured, the break up is not particularly bad on this woofer, but there are nicer ones. Too bad they'll generally cost you more if you want high efficiency and stay in the pro domain.

Damping will also clean up your Impulse Response and of course all the graphs derived from it.
Before damping:

After Damping:


Hopefully I answered your question(s) I kind of got off on a tangent.:o

Dan

[Mayhem13]

Re: Flex Your PCD Mettle:

Perfect example of MFGR's measurements not being accurate....an all. The Eminence graph shows NO such breakup indicated by your measurments. Thanx for al the hard work.......and saving me the trouble on the Pro-12A's

[dantheman]

Re: Flex Your PCD Mettle:

That's unfortunately why I bought the speaker--the manufacturer's graph looked good. You just can't trust them. :(

Edit: You're welcome. Sorry I didn't say it in the first place, your comment flipped my rant switch.

Dan

[Mayhem13]

Re: Flex Your PCD Mettle:

After reviewing all of the designs both here and over at AK, i'm of the opinion that Ewave SR represents the HIGHEST value vs performance factor design of all those with available drive units. For the cost of the Dayton 12", performance is excellent and the horizontal polars for the design simply outstanding....hat's off to Zilch and Pete.:D

Now given the relatively low cost of the SR as compared to Deluxe, i'm reserving the drive to build em just yet as i think there's some room for improvement in the HF section....other than the substitution of the D220i with the DE250 which for the most part have been the predominant players here.

PE's recent aquisition of RCF products might be just the motivational factor to give their waveguide(s) and Mylar CD a try? The combined cost of the two is right in the ballpark of the DE250 stand alone. A guy could hope?:D

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=294-818

Other than contributing meaningless conjecture and speculation, i should probobly just get off my a&$ and set up a Soundeasy measuring system as i've wanted to do for some time now but the older i get, the less i'm motivated to learn something new as i don't think there's any room up there for more data!:eek:

If not, i'll just build the Selenium version anyways.

[edlafontaine]

Re: Flex Your PCD Mettle:

More speculation:

I've got to wonder when considering the Eminence offerings, if the neo-variations, Deltalite and Kappalite, have less of the
"break-up" in their response.

the manufacturer's graph looked good. You just can't trust them

After "seeing" the Deltalites measured, I have to agree with this. One cannot make an evaluation for the benefits for choosing Kappalite over Deltalite based on the paper Eminence provides. :rolleyes:
That is something I'm trying to decide.

[Mayhem13]

Re: Flex Your PCD Mettle:

I've been wondering if the added cost of the Eminence Neo's isn't equalled in performance gains over the non-neo cousins, but instead represents the reduced weight factor, for the professional,portable users. I'd like to hear your subjective impressions of the Ewave you've built Ed, as you've been around here a while and i dare say i trust your ears. I'm afraid i'll be trading away....er.....something for the dynamics, efficiency, and low cost of and Ewave. There's surely room for improvement in all of the Ewave models with construction techniques by the way of roundovers, flush baffles, cabinet bracing and the like but i think Zilch has done an excellent job with the 'Core' systems and Pete has been very considerate yet frugal in his XO work keeping these affordable. Could each benefit here and there from an extra circuit ot two?.....maybe.

Am i looking to build the best Ewave possible?....No. Just maximize the design for my own listening space and tastes. I've convinced myself that there's perfrormance gains to be had with Ewave over my so called HiFi woofers and Waveguide mounted dome tweeters......i just hope it's the gains i'm looking for...subjectively speculating of course.

[augerpro]

Re: Flex Your PCD Mettle:

My own 2 cents on the Eminence neo versus ceramic: The neo's are new woofers designed with modern computer models, and I believe there is something about the size of the neo magnet (and magnetic properties) that is enabling much better non-linear performance over a comparable ceramic woofer. Looking at my own results for non-linear disortion and Le(x) for the 3012HO, you would think this would HAVE to have shorting rings, if not a full copper sleeve. But it does not. Informal testing of the 2512 also shows good non-linear performance. 3rd party tests of some 18 Sound 6" neo midranges also shows excellent non-linear performance also, and they did not have shorting rings. I'm not saying ALL neo motors are better than ceramic all else equal, but it does seem the most recent offerings designed by the right people with modern computer models do seem to be a step up over their ceramic siblings.

[Zilch]

Re: Flex Your PCD Mettle:

Thank you, Brandon, for this insight.

Like alnico, neo is electrically conductive, whereas ceramic is not.

I'm not a student of transducer motor design and thus do not understand the implications, but with respect to performance, something inherent matters.... ;)

40045/651=61.5131

[winkun]

Delite 10 project finished!

I just finished my ZilchLab Delite 10 project today and they sound great. Cabinets were from Radio Shack Nova 8 thrift store purchase. I've been playing them for about an hour and not a problem or complaint. Definitely keepers. Damn, they go LOUD. They do need a sub to fill out the bottom, what with the 1.6 cu ft sealed cabinet and 2510 Deltalite. Mids and highs are just fine. Mighty fine. Many thanks to Zilch and all the others who do the work and then publish. Great job.

[dantheman]

Re: Flex Your PCD Mettle:

Winkun, those are awesome! Congratulations man.

Dan

[Zilch]

Re: Flex Your PCD Mettle:

Winkun has the honor of being the 100th EconoWave builder registered in the main thread on AudioKarma.

I have begun a list here on Tech Talk as well; be sure to post your completed project for recognition here. If I miss your post, just send me a PM with a link to be included:

http://techtalk.parts-express.com/showthread.php?t=215536

[edlafontaine]

Re: Flex Your PCD Mettle:

Well done Winkun ;)

Thanks for your comments Brandon. ;)

Mayhem posted:
I'd like to hear your subjective impressions of the Ewave you've built Ed

The E-Wave Delites:
On the judges cards @ MWAF they tied for second place in the over $200 category. Concerns noted by the judges included "honk" & "mid-range coloration". These were set up to optimize the imaging for the judges, using a toed-in "crossfire" orientation. It worked for the judges...not so well further back in the room. In my listening the axis' cross about a foot in front of my head...
My ears: I get pretty good correlation with my comments to others about bass balance. In high frequencies my ears are not to be trusted...too many years and too much construction.
I think I had too much stuffing right behind the driver. I removed some after the competition. I think this is an area not to be overlooked.
Measurements taken by Robert show a smooth response. Changes to these speakers are going to be subtle rather than affect the overall character.
At this point they are musical and can be listened to all day.
I have noticed one unusual aspect. That is the "distant" quality of the music. They are near the wall on one end of my home. On the other end of my home, in the bedroom, I hear more of the music coming down the hall than I did with the ML Modula MTM's they replaced. The Modulas will have to find another home. :rolleyes:

These are a work in progress. They are a joy. Areas of interest include:

I'll add subs to these. In my alignment they lack only the lowest bass...and not much at that.
I'll continue to play with the stuffing to find a balance with damping and reflected internal backwave.
I'll continue to play with the toe-in.
I'll refine the QSC 152i throat to merge seamlessly with the B&C DE250. I'm going to kludge something together with~3/16" polyethylene between them.
The mouth termination of the waveguide might be improved. I'm looking at a spiral curve with ~6" radius rounding to ~3/4" radius, a la LeCleach.
I will probably try 30 ppi reticulated foam as Geddes does.
As noted, I'd like to hear them with the 3012HO's. Someone who should know has noted the Kappa's have some 2K honk to be dealt with. Sim's with Martin's worksheets tell me the 3012 HO & LF would drop right into this cabinet. At this point I'll see what happens through working with what I've got.
:D Unless someone wants a good deal on a pair of low-mileage 2512's :D

[Mayhem13]

Re: Flex Your PCD Mettle:

Excellent....and 'barely' subjective i might add.:D My range ends at 15k myself as i've spent 10+ years in the music industry myself and the last 10 working with Harley Davidson:eek

I'm torn between the Delite10 and the SR variant....cost concerns being one and the low frequency extension being the other as my intent is to place these on top of ported RSS315HF's and crossed actively. The Deltalight 2510 has an almost perfect rolloff for an 80-100hz cross to a sub.....in a small box and i suspect does not suffer from the 2k honk mentioned which i suspect is caused by beaming of the 12" woofer as it correleates to the wavelengths of the drivers diameter. The 10" driver might fair a bit better here....i'm not sure.
In any case, if i can't or won't part with the $180 for a pair of 18sound WG's, i think the 152i guide and the DE250's is the way to go with the 2510. Given the more 'roomy' baffle this creates fot the 10" woofer, there's a possibility of offset which may improve imaging as well and relieve the need for toe-in in my somewhat narrow (12ft) HT. If you're wondering why i keep going back to the 2510, it's because i already have a pair on hand.

Thanx for the listening impressions....it's helped a lot.