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DIY Array-O-Wave. Yesterday's progress - pix

Spalls said:
Great lookin' project, Dennis! I spent some time making sawdust today myself. Nice way to spend a weekend.
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That's what I said to George Saturday. It was a great way to spend the day. Good luck you your project.

Copa1934 said:
Nothing beats support from the better half with such a project. Really adds to the pleasure of it all.

Nice work. Can't wait to see more images.
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Yep, Annie is very supportive. Couldn't do it without her. I have a few more things to do then I will move them into the house tomorrow and hook 'em up proper like. More images to follow.
 
I went back and read my impressions and thought, WOW that almost sound too good. But I've come to the conclusion that I had absolutly no expections that these would sound very good at all. It was always JUST and experiment. I guess they are just a lot better than expected. And yes, moving from Edgarhorns to these, I've been a little snotty about these "cheap ass speakers"....shame on me.

Here are pix of the first one wired. What a mess.
 

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I hear ya. Kris (my wife, duh) has put up with a full blown woodshop, 5 classic project cars, a dozen or so speakers and projects, a few dozen model cars/planes yet to be assembled. Last Wed was our 26th. We've been together 30 years now. Hasn't been perfect sailing, but we've made it this far.

I guess what I'm trying to say is it's nice to have an understanding partner.
 
Ah the old spaghetti farm. Nice. How did you arive at whatever values your using for caps, attenuators, etc?
 
Line arrays have been around a very long time, and over the years, designers have worked out ways to improve their performance with shading and/or steering. Ray can tell you more, but basically, it's about progressively modifying the output of the more outward drivers to minimize interference with those more toward the center.

In mentioning this to you on another site, I was referring to some of the latest work of Keele with respect to trying one of his more recent schemes to accomplish this, scaled group delay, as shown here:

http://www.jblproservice.com/pdf/CBT/CBT 50LA-WH.pdf

I don't know how well it would work with your project, but I believe I'd be trying that out experimentally. You can read up on arrays at his website; he's been working on the leading edge of their design in recent years, and some of the background information in his papers provides perspective on the relevant issues and historical solutions for them:

http://www.xlrtechs.com/dbkeele.com/papers.htm

Yah, Keele is "World Class...." :yes:
 
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Thanks for the links Z. I understand now. At first I was going wire it as a Bassel (SP) array, but the drivers are high 80 spl and the Bassel schem actually lowers that. Wired as they are now, they are 98db eff. and that just made more sense as all but one of my amps are SET.

Looks like I have a lot of good reading though at Keele's site. Cheers.
 
Copa1934 said:
Ah the old spaghetti farm. Nice. How did you arive at whatever values your using for caps, attenuators, etc?
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Hi Copa, that is the origanal EconoWave crossover I had left over from another project. You can find it on the first page of the EconoWave thread that Zilch has kept going.

I will do some tweeking but it is a great start. I really need to get the other one done (1/2 hour) and set them up in my room with the subs to do some critical listening.
 
I got to listen to Keele's own CBT arrays (pictured at the left about halfway down here) a few weeks ago. They are indeed impressive.

They're kind of the opposite of a waveguide though, in that the sound field is pretty much the same anywhere you go in the room. They do have controlled directivity but everything is evenly distributed through the room. Kind of hard to explain. He does a much better job than I. Using a CBT in conjunction with a waveguide might give some really funky results.
 
For the first three hours of the first speaker I completed, they did sound funky, but I had it running right next to my bench with the top 2 drivers at ear level. But then I set just the one up 7' away from my listening position (in the garage) and I can't tell when any one driver OR the wave guide is playing. Very well blended. I am going out to the garage in 10 minutes to finish the other one. They will be set up in the house with the subs by mid day. Through out the day I have 3 or 4 AKers coming over to give them a listen.


The eWave crossover is the origanal set up for 8ohm. I never actually checked the ohms of the mids before I started this project as I didn't know what having 8 of them would do. I measured them late last night, all wired up, and they are 3.9 ohm.

Question: Do I need to change anything in the crossover?
 
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I just finshed the second speaker and both of them measure 3.9ohm on the mids. They sound great even running them with a boom box in my garage.
 
Yeah, with that wiring scheme you'll get an impedance that is 1/2 that of a single driver so 4-ish sounds about right. To get the crossover point back to the right place (assuming the XO was originally designed for 8Ω) you'll need to double the cap. If there's an inductor you need to halve it.
 
Dennis,

On the crossover, simply follow Ray's advice, as he's (once again) right on the money.
:thmbsp:

I purchased a box of those drivers when they went for 49 cents (the shipping cost more than the drivers!). Another guy and I measured them and they were both consistant and quite good. In fact, they measured better than my friend's $49 Audax 4 inch drivers. They sound is quite nice right out of the box and the only downside is the narrow mounting flange which is inadaquate, IMHO, for a tight seal around the driver. I haven't tried any of the usual driver mods on these, but I'm sure that they can be improved to some extent.

I gave away a bunch of these, mostly to kids for Boy Scout projects, but luckily I kept a few for myself. Maybe I'll have to do something with them yet, Dennis' project is certainly inspirational!
:D

Best Regards,
TerryO
 
Thanks Ray and Terry. Yes the flange issue would be a problem but the tiny gaps I can see light through on an open baffle shouldn't cause a problem. I will change the crossovers as soon as I can.

I've been listening to them in the garage for the past 5 hours and I still think this is a winning combo. I now see some areas for improvement, but I will wait until I drive them with something other than a boom box.

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djnagle said:
Thanks Ray and Terry. Yes the flange issue would be a problem but the tiny gaps I can see light through on an open baffle shouldn't cause a problem. I will change the crossovers as soon as I can.

I've been listening to them in the garage for the past 5 hours and I still think this is a winning combo. I now see some areas for improvement, but I will wait until I drive them with something other than a boom box.

IMG_3988.jpg
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Dennis,

Those speakers will sound much better when you turn off your shop vac!
:nono:

Best Regards,
Terry
 
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