Zilch's AK Design Collaborative - Econowave Speaker

[Rational35]

The universe unfolds, and Zilch just smiles.
He woulda just loved this exercise.
Happy New Year Zilch, wherever you are.

<edit> damn, typing that just made me cry.

 

[Pio1980]

The universe unfolds, and Zilch just smiles.
He woulda just loved this exercise.
Happy New Year Zilch, wherever you are.

<edit> damn, typing that just made me cry.

I think of him and his legacy every time I sit to listen thru the Advent 2 Econowaves.
I'd like to see Gordon build a pair and pass judgement on them, the mid-woofer is really an overachiever with this setup.

 

[Katalyst]

Yes the low point between those 2 impedance peaks is essentially the box tuning ( Fb ).

The attached picture is the same box with one 2.5 inch .75 port. The Betsy driver is the only difference. The driver makes a big difference in the same box. JbL 2204h/120e is 35hz tuning. The Betsy 47.1hz. The dats system is showing the actual Fb correct?

 

[EarlK]

The attached picture is the same box with one 2.5 inch .75 port. The Betsy driver is the only difference. The driver makes a big difference in the same box. JbL 2204h/120e is 35hz tuning. The Betsy 47.1hz. The dats system is showing the actual Fb correct?View attachment 1379380

The DATS system is showing Fb ( actual box tuning ).

The driver ( woofer ) should make little difference to the measured box tuning ( it's simply a wind source blowing across an open soda bottle then reflected back into the woofers own impedance ).
- Obviously a much smaller woofer displaces less internal volume / but one can see that difference in the online sims.

Since your impedance curve says Fb has changed, then I would guess the box has developed some air leaks ( which will indeed effectively raise the tuning frequency ).

The leaks could be coming from the adapter plate or the back panel ( all dependent on how many screws are being replaced, how tight they are, & how well the original seal is holding up to all this continued activity .

 

[Austy]

Morning e-wavers! I have a pair of l55 with the le14a I would like to ewave. I am having a but of trouble working out the parts list. The I cant get all the links working in the earlier part of the thread. Is that where I should be headed?

 

[turnitdown]

Yes. I'll post the crossover. Just a sec...

 

[turnitdown]

 

[turnitdown]

That's a good start.

 

[Austy]

Great thanks turnitdown, now what compression driver/eve guide would you recommend? This is zonkers pic. Looks like the be250?

 

[turnitdown]

That's the JBL horn that takes a 1 inch driver. He may have used the Selenium D220ti which is VERY respectable. IF you have the room, a little extra coin and the inclination, step up to the workhorse B&C DE250 on the B52 10x14 wave guide. At the beginning and, well, to this day, that remains the deluxe choice because it is so proven and pleasing. Bonus, there is a crossover for that out there also because the combo is so popular. I use the LE14 anywhere I can as it is arguably one of the finest low frequency drivers in the JBL lineage.

 

[Austy]

Thanks again. Looks like I have more reading/investigating to do

 

[wiredbecker]

Hi Austy, I put together an updated le14a Econowave parts list recently. Expect a PM from me with the info you're looking for.

 

[turnitdown]

Hey wired, updated in what way? Are there changes that make improvements?

 

[Austy]

I think I'll have to go with the seleniims instead of the b&cs. The aussie dollar is so low at the moment. I'll look forward to the PM wiredbecker.

 

[Mazza]

I think I'll have to go with the seleniims instead of the b&cs. The aussie dollar is so low at the moment. I'll look forward to the PM wiredbecker.

From one Aussie to another I went the Celestion CDX1-1745 as an alternative to the B&C 250 (due to cost reasons) on the advice of EarlK here.

The Celestion is available locally in Aus and I got mine from Belfield Music with free shipping.

I've been listening to these for several months now in my system and they are very smooth. I've actually switched off my centre channel they image so well, with a healthy toe-in per Geddes/Parnam specifications.

Hope this helps.

 

[Rational35]

From one Aussie to another I went the Celestion CDX1-1745 as an alternative to the B&C 250 (due to cost reasons) on the advice of EarlK here.

The Celestion is available locally in Aus and I got mine from Belfield Music with free shipping.

I've been listening to these for several months now in my system and they are very smooth. I've actually switched off my centre channel they image so well, with a healthy toe-in per Geddes/Parnam specifications.

Hope this helps.

The Celestion CDX1-1745 is a smooth, well-respected driver by all accounts, and the price is reasonable. (at least here in Canada).

National dollar-values and stupid trade-war tarriffs can have significant impact on our hobby plans.

I was looking at Eminence N151M-8s for use in some mini 2-way systems, and as super-tweeters in larger systems. But, they've nearly doubled in price here over the past 6 months, so now I'm looking at B&C DE-10s again (which have stayed steady at C$59).

The Peerless by Tymphany DFM-2535R00-08 is also well-regarded by the likes of Bill Waslo. It's very reasonable in US$ from Parts Express, but by the time I pay dollar exchange and shipping and import fees into Canada, not so much.

Solen (Canada) also has some interesting budget CDs from Fane (CD130/CD131=screw-on/bolt-on) which look promising in the C$59 range... or the CD140 and CD150 series for a bit more money in the 44mm voice coil class. Does anyone have any experience with these? I guess I'll have to bite the bullet, buy up a pair each (of what's in the reasonable price range), and do some measurements and listening tests.

<edit>: to be clear, I'm talking about two different classes of drivers in the same message here: smaller 25mm-34mm voice-coil drivers for (3-way, or mini 2-way) tweeter duty, and larger 35mm-44mm voice coil drivers more in keeping with the Econowave principle. It all turned into a flow of thought...
https://www.fane-international.com/downloads/Fane-CD131-DS240316.pdf
https://www.fane-international.com/downloads/Fane-CD140-DS240316.pdf
https://www.fane-international.com/downloads/Fane-CD150-DS240316.pdf
These drivers have no distribution in North America except Solen, AFAIK, but they seem to be very well-regarded in other parts of the globe. The 131 is direct price competition to the DE-10. The 140 and 150, more-so with the DE-250 class. The 140 and 150 also use ferrofluid in the gap. German users report excellent performance in commercial PA/Club sound using the CD150 from 1.6kHz up. The Celestion is a better price, all other things being equal.

 

[wiredbecker]

Hey wired, updated in what way? Are there changes that make improvements?

Updated in that Parts Express updates their products and we scramble to find suitable replacement parts!

I couldn't find my original parts list so I worked up a new BOM from Jackgiff's crossover values on Parts Express for the LE14A. All components are pretty straightforward with the exception of the inductors. L1 calls for a .6mH air core inductor with a DCR of .53. L2 calls for a 2.0mH iron core inductor with a DCR of .143. I can't recall exactly what needs to be done to get the correct DCR.

Can someone help me/us out with the answer? It's been what, 10 years since I've built up this particular Econowave build!?! Big love to Zilch and Jack Giff.

Here's what I came up with for the LE14A Econowave build.

C1: Dayton Audio DMPC-4.7 4.7uF 250V Polypropylene Capacitor
Part # 027-422

C2: Dayton Audio DMPC-15 15uF 250V Polypropylene Capacitor
Part # 027-432 $5.79

C3: Dayton Audio DMPC-1.5 1.5uF 250V Polypropylene Capacitor
Part # 027-412

L1: Dayton Audio 0.60mH 14 AWG Perfect Layer Inductor Crossover Coil
Part # 257-312

L2: ERSE 2.0mH 18 AWG I Core Inductor Crossover Coil
Part # 266-554

R1: Dayton Audio DNR-16 16 Ohm 10W Precision Audio Grade Resistor
Part # 004-16

R2: Dayton Audio DNR-25 25 Ohm 10W Precision Audio Grade Resistor
Part # 004-25

LPad: L-Pad 50W Mono 1" Shaft 8 Ohm
Part # 260-255

Binding posts: Dayton Audio BPA-38SN HD Binding Post Pair Satin Nickel
Part # 091-1247

Waveguide: Dayton Audio H6512 6-1/2" x 12" Waveguide 1-3/8"- 18 TPI -
Part # 270-318

Compression driver: Selenium D220Ti 1" Titanium Horn Driver 8 Ohm 1-3/8"-18 Part # 264-270

Just cut and paste the actual part # into the Parts Express search window to find the part you're looking for. 264-270 takes me right to the D220Ti.

 

[turnitdown]

Thanks Wired, that's going above and beyond, as usual. I was afraid there was some additional tweaking/improving going on in another thread or something, and because I have that build in service, I want it to be the best it can be.

 

[Rational35]

The DCR of the inductors is determined by the wire gauge of the winding.

A 14 AWG coil will have a lower DCR value than an 18 AWG coil of the same inductance value.

An I-core inductor will have a lower DCR value than an air-core of the same inductance value, with the same AWG.

I-cores should only be used in woofer circuits, then only if you can't afford stupid-large-AWG air-cores.

Exotic (molypermalloy (MPP) or Sendust) powder cores can take this to another level, but not readily available to the average hobbyist.

More later...

 

[Rational35]

L1: Dayton Audio 0.60mH 14 AWG Perfect Layer Inductor Crossover Coil
Part # 257-312

That's a nice inductor, but really, it's overkill for the L1 position in the tweeter crossover.
It doesn't need that large gauge of wire. It doesn't carry much current.

Jack Gifford spec'd a 0.53 ohm DCR inductor in that position, and the 14AWG coil is 0.19 ohm. That would be nice in a woofer circuit, but you don't need it here.

Save some of your hard-earned money for other things, and use one of these:

Dayton Audio 0.60mH 18 AWG Perfect Layer Inductor Crossover Coil, Part #257-818
It's still overkill at 0.38 Ohm, but would work more than fine.

Dayton Audio 0.60mH 20 AWG Air Core Inductor Crossover Coil, Part # 257-040
This one is 0.56 Ohm DCR. Within normal tolerances, I suspect this is what Jack used, and will work fine.

Now, for the woofer coil:

L2: ERSE 2.0mH 18 AWG I Core Inductor Crossover Coil
Part # 266-554

That one's a bit light-duty for the application, the DCR is a bit high at 0.26 Ohms.

The one that Jack originally used is this:
ERSE Super Q 2.0mH 16 AWG 500W Inductor Crossover Coil, Part # 266-904

If the physical size/shape isn't a problem for you, this one will give better performance (lower losses) in the woofer circuit, for a dollar less:
Jantzen 5811 2.0mH 13 AWG P-Core Inductor, Part # 255-157

Hope this helps