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Zilch's AK Design Collaborative - Econowave Speaker

The ponderous plod of progress

More photos of the latest OLA Ewave conversions. Veneer done. One coat of Tung on the veneer. All screw holes drilled. Old cab baffle butchered for clearances. Brass angle cut, fitted and drilled. woofer fabric chosen and test fitted.
You can't see the colors here. The rosewood is a nice reddish tone. The fabric is nylon sheer with a mahogany brown color that does not reproduce wit ha flash.

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I had to get out of bed, half asleep, to write this post. I fell asleep thinking about small scoops and then it hit me and I was awake. BK16, sans driver, from madisound. Stick a real woofer in it and it might do the trick. Anyway, I am going back to bed.
 
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djnagle said:
I had to get out of bed, half asleep, to write this post. I fell asleep thinking about small scoops and then it hit me and I was awake. BK16, sans driver, from madisound. Stick a real woofer in it and it might do the trick. Anyway, I am going back to bed.
Click to expand...

That looks like a Fidelio back horn. I had a pair and George F has them now. I used them with Lowther DX3s in them and Khorn bass bins as subs. I liked everything about that except the Lowthers. I dunno about long back horns. More like a TQWT in some ways, black magic in others.

Hey, for a while in Audio Xpress Bill Fitzmaurice was publishing plans for PA midbass horns that were mad sensitive and not overly complex by horn standards. I have those issues around here somewhere. Bill may not be particularly supportive of ewave personally, as it's contrary to his own philosophy in some ways. But his woofer horn designs look well thought out and IIRC have solid output down into upper subwoofer territory (100 hz). Lotta wood bending in one of those horns. Lets get George to do it.

*** EDIT***
Yup. Woofer horns.
http://www.billfitzmaurice.com/

http://www.billfitzmaurice.com/OmniTop12.html

One problem. He states 104 db as the sensitivity of one of his woofer horns. With that much level, how would you get any headroom for compensation on the compression driver without biamping?
*** /EDIT***
 
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djnagle said:
Those are beautiful B. They look VERY HIGH END mid fifties. Can't wait to hear them.
Click to expand...

I may have an unmatched pair on Saturday. I'm building one pair of OLA ewaves with the new baffles shown and a second, plainer pair with the PH612 installed in the original baffle, like I did with the Utility Large Advent build. I'll eventually finish off both pairs.

This is a lot of work. It's 4:00 AM and I'm smearing glue on woofers. Time for Scotch and bed.
 
Bauhausler said:
That looks like a Fidelio back horn. I had a pair and George F has them now. I used them with Lowther DX3s in them and Khorn bass bins as subs. I liked everything about that except the Lowthers. I dunno about long back horns. More like a TQWT in some ways, black magic in others.

Hey, for a while in Audio Xpress Bill Fitzmaurice was publishing plans for PA midbass horns that were mad sensitive and not overly complex by horn standards. I have those issues around here somewhere. Bill may not be particularly supportive of ewave personally, as it's contrary to his own philosophy in some ways. But his woofer horn designs look well thought out and IIRC have solid output down into upper subwoofer territory (100 hz). Lotta wood bending in one of those horns. Lets get George to do it.

*** EDIT***
Yup. Woofer horns.
http://www.billfitzmaurice.com/

http://www.billfitzmaurice.com/OmniTop12.html

One problem. He states 104 db as the sensitivity of one of his woofer horns. With that much level, how would you get any headroom for compensation on the compression driver without biamping?
*** /EDIT***
Click to expand...

I wonder if George is using them. If not, maybe we could find the right woorer and stick them in and see how they sound with a WG on top. Might be a fun experiment.

George woke me up this morning calling from the Hamfest in Monroe asking if I needed any 807 to roll into my new amp.
 
OK, I just found the Fidelio on the net and it is a rear firing BLH. I don't know all the particulars, but the front horn mouth on the Scoops, interfaces, somehow, with the front firing woof and the combination is what gives it its great bass.

Edit: I just found this blurb on the JBL Pro site:

"Rear loading horns utilize the back waves of the loudspeaker to energize a long, compactly folded horn. These back waves are coupled to the unrestricted radiation of the loudspeaker’s front waves. The acoustic loading effect of the horn reduces nonlinear distortion and boosts low frequency efficiency dramatically. Above 150 Hz, the enclosure design allows the loudspeaker to effectively uncouple from the horn and operate as a simple direct radiator, with its back wave attenuated by the horn. The upper frequency limit is essentially that of the loudspeaker used (a JBL 2205 or El40 is recommended). Phase inversion of the rear waves, due to the propagation time through the horn length, further augments response in the lowest operating ranges."

Now, for some of you whom are smarter than I, What the f*ck does that mean???
 
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Rear loaded horns only reinforce bass frequencies, above that, it acts like a typical ported/sealed cabinet. BLHs allow the woofer to move less to create the same amount of bass. Reducing excursion reduces distortion (intermodulation distortion or IMD). It's not entirely unlike a ported enclosure in that it's using the backwave to reinforce low bass, both result in lower IMD, as well.
 
BLH dimensions are quite dependent on the woofer being used, I wouldn't expect too many drivers to be readily swappable for others.
 
dnewma04 said:
BLH dimensions are quite dependent on the woofer being used, I wouldn't expect too many drivers to be readily swappable for others.
Click to expand...

So, if a woofer driver could be found with the same T/S, on the low end at least, as the Fostex FF165K, it could be swapped???

I'm going to call Madisound Monday or Tuesday to see home much they want for the flat pack of the cab only. If it is not too much, it might be worth a try


:nono:GEEZ, another project:nono:
 
Actually that's not too bad. I remember these from AKFest 2007 (??) and they were $99.00 each back then and I thought that really was a decent deal.

Remember, all the pieces are cut for you, all you need to do glue them up. Factor in the cost of the wood and the time to set up, rout, and cut a single set, it's actually pretty reasonable.

I guess the low budget approach would to find a couple guys who wanted these cabs, buy a single one and reverse engineer/copy it into multiple cabs. A lot of work for 1 cab, but reasonable for say 3 or more pairs, especially as we used all the cutoffs for smaller parts. It looks like you could almost make one pair out of a single 4' x 8' sheet.
 
This is getting interesting. I wonder if you can get the plans for those cabinets. I have a woodworking shop in basement an could reproduce them pretty easily.
 
there are 10" plans for 10" tannoys in a BLH on the net. Find a 25hz Fs woofer with .25 or so Qts and you'd have the plans you'd need. 34" tall, IIRC.
 
Andyman said:
It looks like you could almost make one pair out of a single 4' x 8' sheet.
Click to expand...

1-Sheet
By approximating cu/in, you could cut the box panels and have @1000 cu-in of material remaining for internals I believe. That could be 10" x about 108" (9ft) if you played your cards right and made no miss-cuts. Not sure if @10" x 4.5'/cab of lineal material would be enough. The internal material would not have to be Baltic though I guess.



A full sheet layout for yield could prove this out. Without a template however...

RC
 
Too small, I think, and too complex. It's not TL we're doin' here.

We want a 10" or 12" driver, probably, and a 12"+ cab width to match up with E'Wave.... :dunno:
 
Zilch said:
Too small, I think, and too complex. It's not TL we're doin' here.

We want a 10" or 12" driver, probably, and a 12"+ cab width to match up with E'Wave.... :dunno:
Click to expand...

That was just a quick thought. I was into full rangers at one time and I remember many scoop type cabs that fit your requirements Z. I do some more lookin' :D

As far as being too complex, I think that is a matter for the builder.
 
So, I always thought that low freq cut off in a backloaded horn is determined by the length of the horn and size of the mouth. If that is the case (and I am probably missing something) We would have to pick a low end cut off and design around that.

My 4530 scoops drop like a rock at 50hz so if we want smaller size, we'd have to accept a higher cut off (probably the wrong term but I am in the middle of building my super power supply (power strip) and just wanted to hammer out this thought. So aren't we back to the size of the BK16 or some variant?

I guess what I am asking is "what are the design paramiters"?
 
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