So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

[Erich H]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

I was wondering myself how low he crossed over. Looking back over Zilch's exercise with the Econowave Deluxe, I was thinking that a reduced crossover point and possibly steeper crossover to maintain sensitivity might provide some benefits for widening the vertical response window and better dealing with the Kappalite's peakiness around 2khz. The waveguide should have a peak load around 1.2khz so I guess it's just a matter of how low and loud you can go with the Denovo or DE250/DE500. It would be interesting to see how Jeff approached this and how well he was able to integrate driver phases.

The Denovo CD was chosen because of how smooth it is. They're basically like the DE250 except they test a little better on the higher end and extend a bit more. Can you hear it? Some probably can, but after many years of landscaping, my ears probably can't. But the OmniMic certainly shows it though. Either of them can be crossed over around 1000hz and I think someone used them at 950hz. Some of the kits have a lower crossover around 1100z.

I can't speak for Jeff, but I'm guessing he chose a higher 1300hz crossover point because the woofer did okay that high and it would allow the speaker to handle some extreme volumes. :D What I hoped for on Jeff's end product was a speaker that could handle everything you threw at it while still sounding nice and smooth with some good mid bass punch when needed. I believe he nailed it and I'm really glad he agreed to help with the project.

[peterlrabbit]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

The Denovo CD was chosen because of how smooth it is. They're basically like the DE250 except they test a little better on the higher end and extend a bit more. Can you hear it? Some probably can, but after many years of landscaping, my ears probably can't. But the OmniMic certainly shows it though. Either of them can be crossed over around 1000hz and I think someone used them at 950hz. Some of the kits have a lower crossover around 1100z.

I can't speak for Jeff, but I'm guessing he chose a higher 1300hz crossover point because the woofer did okay that high and it would allow the speaker to handle some extreme volumes. :D What I hoped for on Jeff's end product was a speaker that could handle everything you threw at it while still sounding nice and smooth with some good mid bass punch when needed. I believe he nailed it and I'm really glad he agreed to help with the project.

Great, that gives me some confidence to experiment with this. And congrats on your DIY group's SEOS success and website. You've proven yourself one of the most important VIPs of the DIY world. Evan would be proud!

[ryanbouma]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

and I think someone used them at 950hz.

You might be referring to me with my current in-wall Delta Max design. I doubt I'll public release it because of that low of cross over though. I don't need people emailing you saying they popped their CD listening at 120db. I don't listen all that loud, so I'm getting away with it right now. It still has significant output below the cross over down to 800hz! I crossed the boxed version of the Delta Max around 1150hz iirc, to keep the vertical lobe really wide for surround use. I tested this thing freakishly loud. I felt my ears for blood. No issues, with the speaker or my ears thankfully. And that's the DNA-350. The DNA-360 is supposed to have more low end *****.

I even crossed the DNA-150 in the SEOS 12 at 1700hz on this design here: http://www.diysoundgroup.com/forum/i...hp?topic=107.0

[Erich H]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

I think Bwaslo also crossed them over around 900 or 950hz with his SEOS-15.

I think you should crank that inwall design up until your ears bleed just to see how much the CD will take. I'll send you another one if needed. But I can't be responsible for your ears! :D

[PWR RYD]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

The $380 is for one speaker not a pair correct? How much is a flat pack? I didn't see it listed.

[Erich H]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

The $380 is for one speaker not a pair correct? How much is a flat pack? I didn't see it listed.

The flat packs will be listed shortly. They're done, I just need to get photos of them before posting.

The kits are listed as singles and they do come with the CNC cut baffles. The reason I thought it was good to include the baffle was because the box itself is fairly easy to cut, but recessing the waveguide to the correct depth is much easier on a CNC.

The Definimax woofer for that model is $200 if I recall, and the CD is about $75. So that's one of the more expensive models. The main goal I had was to get some extremely well priced kits for the SEOS so more people could try them out, and then some higher priced ones in case anyone wanted to go that route. They're all really good though.

In the next week or so, the designers might be able to start explaining some benefits of their own designs and things like that.

[PWR RYD]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

Cool, thanks. My roommate from college has been asking me to help him with a pair of speakers and this design looks near perfect for him. The CNC'd baffles would make my life much easier as I would only need to cut and flush trim the rest of the enclosure panels for him. Or maybe I could talk him into buying the flat packs as well... then my role is purely as a consultant :D

[Jeff B.]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

I was wondering myself how low he crossed over. Looking back over Zilch's exercise with the Econowave Deluxe, I was thinking that a reduced crossover point and possibly steeper crossover to maintain sensitivity might provide some benefits for widening the vertical response window and better dealing with the Kappalite's peakiness around 2khz. The waveguide should have a peak load around 1.2khz so I guess it's just a matter of how low and loud you can go with the Denovo or DE250/DE500. It would be interesting to see how Jeff approached this and how well he was able to integrate driver phases.

I never predetermine a crossover point before I begin designing. I may have an area I target or hope to hit, but I allow that to float during the design process. The first thing I do is measure the response with the actual phase response. Then I determine the relative acoustic offset between the two driver's acoustic centers. Then I begin the crossover modeling. When you do this you ususally find that that there is a narrow window that due to the combination of frequency/phase response of each driver, the offset, and the slopes of the crossover employed, that you will get excellent phase alignment without having to "force it" with an overly complex crossover. In this case, that turned out to be around 1.3khz. That's how that frequency was determined and the phase alignment and frequency response are both excellent as a result.

The Denovo 360 and the 12" SEOS waveguide are both excellent, and very easy to work with . Here is the frequency response of this combination at one meter (ignore the level, that's arbitrary), I used 1/48th Oct. Smoothing and 8mSec gating.






I am sure that in some combinations with different woofers it may crossover well at 1khz. It does have a very nice response.

Jeff

[Pete Schumacher]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

I never predetermine a crossover point before I begin designing. I may have an area I target or hope to hit, but I allow that to float during the design process. The first thing I do is measure the response with the actual phase response. Then I determine the relative acoustic offset between the two driver's acoustic centers. Then I begin the crossover modeling. When you do this you ususally find that that there is a narrow window that due to the combination of frequency/phase response of each driver, the offset, and the slopes of the crossover employed, that you will get excellent phase alignment without having to "force it" with an overly complex crossover. In this case, that turned out to be around 1.3khz. That's how that frequency was determined and the phase alignment and frequency response are both excellent as a result.

The Denovo 360 and the 12" SEOS waveguide are both excellent, and very easy to work with . Here is the frequency response of this combination at one meter (ignore the level, that's arbitrary), I used 1/48th Oct. Smoothing and 8mSec gating.






I am sure that in some combinations with different woofers it may crossover well at 1khz. It does have a very nice response.

Jeff

Nice looking response!

Do you know where the distortion crosses the 1% mark?

[Jeff B.]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

Jeff would you mind sharing your measurements?

Here are some measurements of the speakers. Here is the Quasi-anechoic response of the Definimax / SEOS, normalized to 2.83V at 1 meter:




Here's the input impedance of the system:



Here's the room response measured in my family room at one meter on the tweeter axis with 1/48th oct smoothing. You can see that there is decent response to the 30Hz range:



Here is the version with the Delta Pro 12A under identical conditions. It has a bit more midbass energy but begins rolling off in the 50Hz region:




As you can see on both, the response of the SEOS and the Denovo-360 are quite flat through their entire operating range.

Not many people would show you all of this, but not me, I'll put it out there.

Jeff

[peterlrabbit]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

I never predetermine a crossover point before I begin designing. I may have an area I target or hope to hit, but I allow that to float during the design process. The first thing I do is measure the response with the actual phase response. Then I determine the relative acoustic offset between the two driver's acoustic centers. Then I begin the crossover modeling. When you do this you ususally find that that there is a narrow window that due to the combination of frequency/phase response of each driver, the offset, and the slopes of the crossover employed, that you will get excellent phase alignment without having to "force it" with an overly complex crossover. In this case, that turned out to be around 1.3khz. That's how that frequency was determined and the phase alignment and frequency response are both excellent as a result.

The Denovo 360 and the 12" SEOS waveguide are both excellent, and very easy to work with . Here is the frequency response of this combination at one meter (ignore the level, that's arbitrary), I used 1/48th Oct. Smoothing and 8mSec gating.



I am sure that in some combinations with different woofers it may crossover well at 1khz. It does have a very nice response.

Jeff

Thanks for the response. I think most of us operate in a similar fashion. The minimum number of components to achieve good phase and amplitude tracking doesn't usually come about in a forced situation. I routinely juggle component values and sometimes offset to dial in the best overall response and driver integration. I was anticipating running the Denovo or a DE250 (possibly 500) down to around 1200hz give or take. I just wasn't too sure how low I could go with a one inch CD before the performance penalties start to outweigh the benefits. I haven't done anything with a compression driver in many years so this is a bit outside of my comfort zone. The general consensus though is that these things are pretty robust and clean even run down below manufacturer's likely conservative minimum crossover points. If I wind up building this, I'll post a few sets of distortion plots covering low, medium, and high SPL as I haven't seen that information yet online despite the vast amount of data already posted about Econowaves thus far.

Nice pancake flat response, btw! Great job.

[Jeff B.]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

Nice looking response!

Do you know where the distortion crosses the 1% mark?

Just doing a quick guess from this chart it looks like around 700Hz or so. Most of the distortion is second order. Third order is really very low, running at about -65dB over most of the range. Erich has a very nice little driver here. Kudos to him.

[Pete Schumacher]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

People who are proud of their work have no problem posting stuff like that. Very nice indeed Jeff. And your living room is impressive in its own right!

I can see why you like the 12A version better for rock. There's a general increase in energy from 500Hz and down. Most rock recordings give short shrift to the bass section. It's like they're expecting the rock heads who listen to already have the bass knob cranked up. I've even opened up some of those favorite tracks and applied EQ to restore some of that bass energy, and then wrote the file back to the hard drive with the new EQ as my default playback.

Both responses look incredible for in-room. What do the distortion levels look like under the same conditions?

[Pete Schumacher]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

That's a nice performing tweeter! 1000Hz and lower is no doubt workable. It all depends on how hard you are going to drive it. Most home situations will never tax this thing. And you can power the system to very loud levels with a mere 30W amp.

[donprice]

Re: So who's going to build Jeff Bagby's Definimax-12/SEOS Econowave?

Cool, thanks. My roommate from college has been asking me to help him with a pair of speakers and this design looks near perfect for him. The CNC'd baffles would make my life much easier as I would only need to cut and flush trim the rest of the enclosure panels for him. Or maybe I could talk him into buying the flat packs as well... then my role is purely as a consultant :D

Flat pack = more time to focus on nice veneer job or other finish.

Nice work there Mr. JB!