Zilch's AK Design Collaborative - Econowave Speaker

Always start with bigger speakers "borrowed from a friend.... just temporary, dear, to try them out". After a few days, replace with the not as big ones that you want. They'll be loved, then.
 
I've received a lot of emails and private messages over the last several weeks, with questions about common design issues. I put a lot of that in the "Notes for the DIYer" thread, but there is a lot of information that sort of "built up" to that thread but wasn't included. Things like how to perform certain measurements, how to calculate the volume displaced by a horn, driver or port and why baffle step compensation doesn't make sense for a large speaker designed for constant directivity. So I've made a FAQ page that has a lot more information from the dozen or so years on the Pi Speakers forum:

Some Pi Forum members asked me to create this FAQ. I think most of the Econowave and SEOS enthusiasts are familiar with these things, because I see many of these concepts described on Econowave and SEOS related threads, often quoted from old Pi forum posts or if not quoted, written verbatim. So that's good, I think, we have a dissemination of the information. But instead of having it scattered here and there, it might be helpful to have it all in one FAQ.
 
I am going to do an econowave project as an idle mind gets me into trouble. I am trying to figure out where to start. I have 4 pairs of speakers that might make a good basis for the project.

1) Realistic Optimus 400 c/w 12" woofer - my biggest concern is that the speaker ratings show a 40-20,000 Hz range and I really like my bass.

2) Sears Professional Series SP-2710 c/w 12" Foster / Fostex woofer

3) JBL MRV 310 c/w a 10" woofer - a pretty blah speaker that I will sell if I don't use for the econowave.

4) I am working on a deal to aquire another JBL L26. I have one L26 and one L36 which are my favourite speakers. If this is the obvious route, then I won't feel bad modifying the L26 but I would prefer to add to these two instead.

Any advice would be apreciated.
 
The low pass from Troels Gravesen's revised L26 crossover is actually pretty darn close to the Econowave Delite 10e woofer response. That doesn't mean your time alignment would come out right, but it might be worth a go (combining Troels' L26 low pass with the Delite 10e HF). Assuming measurement is not an option here, that is.
 
Dumptruck, thank you for your help. I have drawn out a crossover based on the HF from the Delite 10e and the low pass from troelsgravesen. Does this look correct?

kneedeepiniteconowavel26_zpsb0f7aa18.jpg
 
I can't be trusted to confirm parts lists - I always mess up my own. I think you've got it, though. L3 is a bit high in DCR for that spot. Try 255-110 for an affordable option there. Same with L4: 255-106 would be better unless you want to step up to much more expensive inductors, which I would not recommend for this experiment - the P-cores do just fine. Oh, and the HF driver polarity may end up better off swapped - we don't know how time alignment's going to end up.
 
Kneedeepinit said:
Dumptruck, thank you for your help. I have drawn out a crossover based on the HF from the Delite 10e and the low pass from troelsgravesen. Does this look correct?
Click to expand...

You might want to confirm that QSC (or someone else) will actually sell you the round waveguide. PE has some that are similar but not bolt-on like the Celestion CDX1-1425 used on the Delite 10e.
 
E-waves are particular about waveguides. The e-wave magic is in the 'constant directivity' high end. If you change the driver to suit an alternate waveguide, you may need to adjust the crossover, but the big question is 'what waveguide?'
 
Kneedeepinit said:
does changing the waveguide change the driver and then the crossover?
Click to expand...

Yes. All 3 work together as a team. However, some substitutions are "close enough" to be quite listenable. It might be easier to take a step back and pick a more common CD/WG combo and then tackle the woofer section.

QSC was swamped for calls to buy waveguides and they quit selling them unless you had a serial number for an original QSC speaker. Are they still enforcing the rule now that Parts Express is stocking the more common waveguide? I don't know...

Look for your part number here...
http://www.qscaudio.com/support/library/schems/Current/HPR/HPR122i_RevC.pdf

www.qscparts.com to order

Looks like SP-000106-GP is it....now obsolete and replaced by PL-000722-TS
Same? I suppose so. Price has increased to $12.50...
 
donprice said:
Yes. All 3 work together as a team. However, some substitutions are "close enough" to be quite listenable. It might be easier to take a step back and pick a more common CD/WG combo and then tackle the woofer section.

QSC was swamped for calls to buy waveguides and they quit selling them unless you had a serial number for an original QSC speaker. Are they still enforcing the rule now that Parts Express is stocking the more common waveguide? I don't know...

Look for your part number here...
http://www.qscaudio.com/support/library/schems/Current/HPR/HPR122i_RevC.pdf

www.qscparts.com to order

Looks like SP-000106-GP is it....now obsolete and replaced by PL-000722-TS
Same? I suppose so. Price has increased to $12.50...
Click to expand...

i may be doing this backwards because I picked a woofer and am looking for a HF driver and crossover to match it. I really like my L26 and L36. I also liked my L110 that I should never have sold.

I think an ewave based on my L26 could be pretty special.
 
You're not doing it backwards, and an L26 e-wave is VERY do-able. Kind of perfect, really. The only question is how to attempt it without measurements. Zilch and his collection of JBL woofers would be REALLY helpful right now.
 
JBL 125A? I think I can help out. The woofer was trashed and I used it for refoam practice. The previous refoam looked like it was done with an inner-tube and construction adhesive. So I used some PE "wet look" paint to hide the hideous cones. Enough paint to affect the response? Who knows.

Give me some time this weekend and I'll run some sweeps. The measuring rig is disconnected.

I was originally planning on using a different 10" woofer but I put the 125A back in the box a couple of days ago. The crossover is the "high efficiency" version with no LF parts. It doesn't sound terrible even with the woofer running full range. I have a small handful of caps and coils so I can build and test something simple.
 

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