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Zilch's AK Design Collaborative - Econowave Speaker

skywave-rider said:
I have to mention that I did not intend to show both QSC 152i and Parham H290C overlaid on one another. But you did a great job Photoshopping that. Wayne saw your overlay and mentioned to me that the H290C should actually have more spl compared to the QSC. The reason it does not in my measurements, overlaid, is because I measured the QSC the next day after I had broken down the test setup. Although I measured from exactly the same distance and placements, I did not have my output pots on my interface exactly the same as the previous day. I know because although I marked my amp setting, I forgot to mark the interface, and i really did not expect to add another measurement anyway. If I was more organized, I would have done them in one session and you could see the spl difference accurately. However, both measurements, on their own, are perfectly good for comparing response, which is what we were looking for in this case.
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'Spose I could have said something here, but probably better you did since you made the measurements and knew your setup and conditions.

There is another clue that may demonstrate the slight difference. Notice the dataset with the H290C/DE250 and the 123A midwoofer shows about -25dB average. Now look at the QSC/DE250 and 123A midwoofer, and it's about -22dB. The midwoofer SPL can be used as a reference, since it is common to both measurements.
 
The DC300 models well when I accept port lengths in the 30 to 40" range. If I go sealed, I get and f6 of 35hz with a start rolloff at about 55hz.
 
I would first like to say how sorry I am to see that Zilch passed. I have read many a post from him, always helping and informing, in multiple forums. It is a great loss.

Now on to "business" that he would probably have loved. I have a few potential Ewave candidates and need advice on which route to go:

1. NLA woofers-I have them already ready to go, no cabinets.

2. Yamaha JA3109 12" 92db cast aluminum framed woofers from some NS 500m speakers same circumstances as the NLA

3. Some complete Pioneer HPM 900's. I do have the cabinets on these. Before cutting them up I would try the upside down cabinet method first

4. 2.5 way using aforementioned NLA woofers somehow in combination with a pair of smaller Advent woofers.

As far as which woofers are most "Disposable", they are, in order:

The yamaha's
The advent's
The HPM's

I don't know the high frequency capabilities of the Yamaha or HPM woofers

I would prefer not to have to use a sub.

Thanks in advance

Jon
 
The high-frequency capabilities of the Yamaha woofers are dubious, as they come from a 3-way design. Same is true of the HPM-900 woofers.

If the other HPM-drivers are OK, they are very good speakers, would be kind of a shame to break them up...but you could get a good price for the drivers--enough to finance a project with the NLA woofers, which are very good for ewaves.
 
Go with the Advents! It's a tried and true build. Keep your eyes peeled for an empty Bullnose or Chamfered Advent cabinet to install them in. They might show up inexpensively needing refoam or devoid of drivers. Also, add your location someone local may chime in with an offer of assistance.
 
The HPM woofers are probably as good as any of the three. They have low inductance, decent high frequency extension and are surprisingly enough, best suited to sealed enclosures, although you can play with the tuning to make them perform better in a ported enclosure than they do in their stock cabinets.
 
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dnewma04 can you elaborate? I have HPM-40s that I CheapoWave'd.

I can vouch for the HOM-40 and 60 woofers (the squareish ones) having very well behaved midrange response. I have no woofer crossover on mine. They meld very well with my smallish waveguides.
 
I have a pair of the 900's and while the response may be good (haven't run WT2), the carbon woofers are incredibly fragile--both of mine are broken. I have no idea if I'm going to toss them out or what.
 
The HPM-100 and HPM-900 woofers both have similar t/s parameters to the Advent woofers. Highish Qts woofers that ideally should be in sealed cabinets. The only issue may be excursion which is an unknown without chopping them up. Running them ported, tuned much lower than in the original may be a good option, as well. Unless you are just a big fan of the west coast bass, which many are, then the stock alignment is fine.
 
That's a good point, Chris. They may have more value on the used market due to their fragility. HPM-100 woofers are probably the better candidate.
 
wiredbecker said:
I have a pair of the 900's and while the response may be good (haven't run WT2), the carbon woofers are incredibly fragile--both of mine are broken. I have no idea if I'm going to toss them out or what.
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They are repairable, I fixed mine with some black glue and some very thin acetate film. They held up fine under a fair amount of "pounding". The black glue came from a speaker surround guy on that auction site. If you would like some pictures and any other info just pm me.

I like the bass of my hpm 900's, but not the highs so much. I would be afraid to put them in a sealed enclosure. I dont know how well that fragile material would hold up.

Someone posted info about the spl of the yamaha's in this thread, but i don't recall if there was any info on the frequency range .

I love the sound of the Advents, but would like to maybe do the 2.5 way, if that results in a lower usable
Freqency cut off point
 
dnewma04 said:
Compared to a ported enclosure, a sealed enclosure's back pressure would be a walk in the park. :)
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I am guessing you are referencing some knowledge and experimentation that has already been discovered/done, but that makes zero sense to me.:scratch2:

It seems to me, and my admittedly tiny brain power, that a woofer moving into the cabinet would face much more pressure increase in a cabinet where the air it is displacing has very little (other than through the dust cap) ability to escape, compared to a ported alternative. And on the way out producing a rising vacuum. I am assuming I am just late to the physics party? Is it related to the resonator effect?

Assuming I am shortly getting a lesson in why I am wrong, I am happy to do it if it provides a better quality low end. Hopefully without much loss in extension

I am still leaning towards the Yamaha woofers, or an Advent 2.5 way. Has anyone done a 2.5 way with Advent woofers before? I searched and only saw 4343 doing a 2.5 way, but it was with different woofers. Would it be a terrible thing to just run both woofers parallel?

I am still trying to avoid a subwoofer, and a small percentage of what I listen to goes lower than my Advents want to.

Sorry so long
 
14G-])utch^;6126637 said:
Would it be a terrible thing to just run both woofers parallel?

I am still trying to avoid a subwoofer, and a small percentage of what I listen to goes lower than my Advents want to.
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I am assuming there would be some comb filtering, which I know little about other than frequencies cancel each other do to the sound hitting your ears at different distances/times from each woofer. But how badly I have no Idea.

Jon
 
Yes, running both woofers in parallel would be bad, AND it won't give you one bit more bass than you get with one, so there's not any point if that's the goal. Stop trying to avoid a subwoofer, and get three.
 
dumptruck said:
Yes, running both woofers in parallel would be bad, AND it won't give you one bit more bass than you get with one, so there's not any point if that's the goal. Stop trying to avoid a subwoofer, and get three.
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Hehe, the Geddes thing? I will have to look into it. Can I stay at your place though, my wife will probably kick me out:D
 
14G-])utch^;6126637 said:
I am guessing you are referencing some knowledge and experimentation that has already been discovered/done, but that makes zero sense to me.:scratch2:

It seems to me, and my admittedly tiny brain power, that a woofer moving into the cabinet would face much more pressure increase in a cabinet where the air it is displacing has very little (other than through the dust cap) ability to escape, compared to a ported alternative. And on the way out producing a rising vacuum. I am assuming I am just late to the physics party? Is it related to the resonator effect?
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Your thoughts seem intuitive, but in reality, as you approach the tuning frequency, the air in the port is moving in the opposite direction of the cone. As the cone moves into the cabinet, the air in the port is doing the same.

A review of a cone excursion plot will show that a ported enclosure will have less excursion than a sealed box at tuning all the way to approximately one octave above.
Assuming I am shortly getting a lesson in why I am wrong, I am happy to do it if it provides a better quality low end. Hopefully without much loss in extension
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The easy way to experiment is to plug the port and see how it performs.
I am still leaning towards the Yamaha woofers, or an Advent 2.5 way. Has anyone done a 2.5 way with Advent woofers before? I searched and only saw 4343 doing a 2.5 way, but it was with different woofers. Would it be a terrible thing to just run both woofers parallel?
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wiring just in parallel would cause issues. a 2.5 way could work, but it's probably unnecessary if you just used the advent 10s, as wiredbecker mentioned, it's a proven build.
 
14G-])utch^;6126799 said:
Hehe, the Geddes thing? I will have to look into it. Can I stay at your place though, my wife will probably kick me out:D
Click to expand...

Tell her they are end tables. The gals love furnature.
 
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