That's why I suggest mounting the woofer and waveguide as close together as possible, and the combination as high on the baffle as is practical and aesthetically reasonable.
Brandon and I have both demonstrated a usable +/- 15° (-6 dB) vertical listening window achievable with the QSC 152i and a 12" woofer snugged up to each other. With a 15", the center-to-center distance will be 1.5" wider, and the forward lobe consequently a bit narrower, but, in any case, taller than if you have them even further apart as would occur when mounting the waveguide atop the cabinet.
Another element in this is where the forward vertical axis is "aimed," and as you see in "Flex Your Mettle," I pay attention to that in these designs; it is easily located by finding the vertical height of the maximal inverse-polarity null. I target that to be somewhere between 2° and 5° above the midpoint (the nominal acoustic center) between drivers and confirm via measurement of the vertical polar response in 5° increments to +/- 20° from the forward axis.
The waveguide itself is +/- 25° (-6 dB) nominal vertical directivity, so all of this is well within its capability. Measure the vertical angle between your listening height and the proposed midpoint between woofer and waveguide at your typical listening distance for perspective on this issue. Note also that the woofer is rear-mounted in all of my designs using the QSC 152i waveguide; the same appears to be the case with your cab. The angle of the forward axis may be further adjusted upward physically by front mounting the woofer and/or flush mounting the waveguide....
Brandon and I have both demonstrated a usable +/- 15° (-6 dB) vertical listening window achievable with the QSC 152i and a 12" woofer snugged up to each other. With a 15", the center-to-center distance will be 1.5" wider, and the forward lobe consequently a bit narrower, but, in any case, taller than if you have them even further apart as would occur when mounting the waveguide atop the cabinet.
Another element in this is where the forward vertical axis is "aimed," and as you see in "Flex Your Mettle," I pay attention to that in these designs; it is easily located by finding the vertical height of the maximal inverse-polarity null. I target that to be somewhere between 2° and 5° above the midpoint (the nominal acoustic center) between drivers and confirm via measurement of the vertical polar response in 5° increments to +/- 20° from the forward axis.
The waveguide itself is +/- 25° (-6 dB) nominal vertical directivity, so all of this is well within its capability. Measure the vertical angle between your listening height and the proposed midpoint between woofer and waveguide at your typical listening distance for perspective on this issue. Note also that the woofer is rear-mounted in all of my designs using the QSC 152i waveguide; the same appears to be the case with your cab. The angle of the forward axis may be further adjusted upward physically by front mounting the woofer and/or flush mounting the waveguide....
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That's why I suggest mounting the woofer and waveguide as close together as possible, and the combination as high on the baffle as is practical and aesthetically reasonable.
Brandon and I have both demonstrated a usable +/- 15° (-6 dB) vertical listening window achievable with the QSC 152i and a 12" woofer snugged up to each other. With a 15", the center-to-center distance will be 1.5" wider, and the forward lobe consequently a bit narrower, but, in any case, taller than if you have them even further apart as would occur when mounting the waveguide atop the cabinet.
Another element in this is where the forward vertical axis is "aimed," and as you see in "Flex Your Mettle," I pay attention to that in these designs; it is easily located by finding the vertical height of the maximal inverse-polarity null. I target that to be somewhere between 2° and 5° above the midpoint (the nominal acoustic center) between drivers and confirm via measurement of the vertical polar response in 5° increments to +/- 20° from the forward axis.
The waveguide itself is +/- 25° (-6 dB) nominal vertical directivity, so all of this is well within its capability. Measure the vertical angle between your listening height and the proposed midpoint between woofer and waveguide at your typical listening distance for perspective on this issue. Note also that the woofer is rear-mounted in all of my designs using the QSC 152i waveguide; the same appears to be the case with your cab. The angle of the forward axis may be further adjusted upward physically by front mounting the woofer and/or flush mounting the waveguide....
I follow you. I think. Yes, this cab is rear mounted. And isn't the point of the waveguide to widen out the "sweet spot" considerably anyway?
But for now, until I have time to try out a different baffle, I'm busting to hear it as it is. It will be a couple of weeks before I have time to experiment with a new baffle.
And voila! After two weeks, it is making music today, albeit with just the JBL, which is an impressive woofer, to say the least. It is loud as all get out if I want to be, but sounds excellent at lower volumes as well. The cab isn't in the corner yet, and it might wind up living in between the JBL 4311s once I mount the TV on the wall.
The low end is really nice. It's not the boomy bass you get from a sealed box, it seems tighter. I christened it with "Drive My Car," and other selections from Rubber Soul, and then went on to listen to some other nice mono stuff I have. Nat Cole's After Midnight album sounds great.
And as I was typing this, FedEx dropped off the XO parts from Parts Express. I've got work to do. Let's see if I can figure it out from Zilch's instructions and the video.
The low end is really nice. It's not the boomy bass you get from a sealed box, it seems tighter. I christened it with "Drive My Car," and other selections from Rubber Soul, and then went on to listen to some other nice mono stuff I have. Nat Cole's After Midnight album sounds great.
And as I was typing this, FedEx dropped off the XO parts from Parts Express. I've got work to do. Let's see if I can figure it out from Zilch's instructions and the video.
Hm-m-m-m, I got rid of all my 811 horns and kept the 511 horns for the same reason! In 30 years I've never got an 811 to sound as good as a 511 for home audio, (to me) but I guess that's why they made both!
Similarly, I never cared for the 804, 806, etc short magnet drivers either, the 802, and 902 have much better extension on the high end. It takes a lot of compensation ( and of course increased distortion) to get them to attempt the extension of these other drivers, which just cant be done.
while I've never tried the Selenium on Altec horns, I have the 220ti and can say two things about them.
1.) Excellent buy for the money, and
2.) Harmon industries (ownes JBL) just aquired them, so if you want them you might want to get them while you can, given JBL's newer policies concerning selling drivers alone.
russellc
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I guess it's all in the crossover! I just find the 811 much easier to work with. It was also much more common in home and studio monitor type speakers, the 511 more common in big venue stuff, for whatever reason. (probably worthy of another tread)
Yeah, heard about Selenium from their US rep who was up at Parts Express for the show. He did not indicate big changes, so I will keep my fingers crossed and hope for the best.
Yeah, heard about Selenium from their US rep who was up at Parts Express for the show. He did not indicate big changes, so I will keep my fingers crossed and hope for the best.
That's JBL Consumer not JBL Pro. You can get just about anything you want through Pro. What we used to be able to get are the horns and drivers for the TOTL consumer systems. Unfortunately that's what they closed the door on. I doubt the consumer driver policy will in any way effect Selenium.
Rob
It's done and making music! It ain't pretty yet, but I'll mount the XO and L-pad later.
Zlich's PCB is a cinch. This was the first time I had ever attempted something like this, and between the youtube video, and Zilch's excellent step by step instructions, even a novice like myself could put it together. Thanks again, Zilch! Here it is shortly before hooking it up:
Zilch, one thing I noticed is that the parts list you enclosed with the PCB specified a different R2 resistor, a 12.5 ohm. I had already ordered the parts from this page you posted in this thread: http://home.comcast.net/~dnewma04/EconowaveBoM.htm
So I have a 30 ohm resistor in there. I know that has something to do with the HF side. Should I change it?
Here is the beast filling the room with sound:
Entirely subjective impressions (I have no way to measure like most of you do): Good lord, this thing sounds great! The high end is so smooth and transparent. I've been playing every mono record I have, starting with the Beatles' White Album. Big, full, clean, wow. It sounds amazing with classical music, absurdly good. I'm hearing details I hadn't before.
The danger is that I'm probably going to want to go stereo--it sounds so good. I'm no carpenter, and I imagine it would not be cheap to hire a cabinet maker to build another cab from the Jensen plans. Oh well, it works, it sounds better than I thought it would, and when I get time to fool with it again, I'll experiment with a baffle like Zilch suggested.
Thanks again for all the help, every one! I asked that question in the right place on the internet, this site is the bomb!
Zlich's PCB is a cinch. This was the first time I had ever attempted something like this, and between the youtube video, and Zilch's excellent step by step instructions, even a novice like myself could put it together. Thanks again, Zilch! Here it is shortly before hooking it up:
Zilch, one thing I noticed is that the parts list you enclosed with the PCB specified a different R2 resistor, a 12.5 ohm. I had already ordered the parts from this page you posted in this thread: http://home.comcast.net/~dnewma04/EconowaveBoM.htm
So I have a 30 ohm resistor in there. I know that has something to do with the HF side. Should I change it?
Here is the beast filling the room with sound:
Entirely subjective impressions (I have no way to measure like most of you do): Good lord, this thing sounds great! The high end is so smooth and transparent. I've been playing every mono record I have, starting with the Beatles' White Album. Big, full, clean, wow. It sounds amazing with classical music, absurdly good. I'm hearing details I hadn't before.
The danger is that I'm probably going to want to go stereo--it sounds so good. I'm no carpenter, and I imagine it would not be cheap to hire a cabinet maker to build another cab from the Jensen plans. Oh well, it works, it sounds better than I thought it would, and when I get time to fool with it again, I'll experiment with a baffle like Zilch suggested.
Thanks again for all the help, every one! I asked that question in the right place on the internet, this site is the bomb!
Though we cannot see the back side, it appears you did an excellent job building the crossover. With the inductor L1 standing on edge like that, you can put a cable tie through its center opening and the two holes provided in the board to secure it. Put a strip of double face foam tape under it first.
Yes, probably, and C3 should be 1.5 mH, but hold off on all that 'til I get the measurements into crossover modeling software next week and hone in on the optimum values for you. I'll be posting all of that in "Flex Your Mettle" on the PE Tech Talk forum.
In the meantime, it appears to be playing enjoyably for you; we'll just make it even better, is all.
The best course would be to take the one you have to a cabinet builder for replication. According to Planet10, above, there are some discrepancies in the Jensen plans....
You won't have to move the woofer down very much to optimize that, looks like. It ALMOST fits already.
Congratulation!
+2
[This is really fun stuff...!
]
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Note: 2220H is one of the JBL woofers having inverse polarity:
http://www.jblpro.com/catalog/support/getfile.aspx?docid=241&doctype=3
Next time you open it up, reverse your connections to the woofer terminals, i.e., your red lead (+ on the circuit board) to the woofer's black terminal, and vice versa....
http://www.jblpro.com/catalog/support/getfile.aspx?docid=241&doctype=3
Next time you open it up, reverse your connections to the woofer terminals, i.e., your red lead (+ on the circuit board) to the woofer's black terminal, and vice versa....
Yup.
Until we get the woofer and waveguide snugged up, it's somewhat of a crap shoot as to which connection polarity might sound best.
[And fun trying out the options....
]
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Here's a thread over at LHF that talks about this horn . The thread is called the Brociner folded corner horn? ( by Jensen )
And here's a second thread about this Jensen folded horn .
They are definately very cool looking LF horns !
I'm confident I'd love the look of an old Altec 808 ( maybe 805 ) multicell situated within that baffle board just over the woofer . That would be uber retro ! .
<. cheers
And here's a second thread about this Jensen folded horn .
They are definately very cool looking LF horns !
I'm confident I'd love the look of an old Altec 808 ( maybe 805 ) multicell situated within that baffle board just over the woofer . That would be uber retro ! .
<. cheers
Though we cannot see the back side, it appears you did an excellent job building the crossover. With the inductor L1 standing on edge like that, you can put a cable tie through its center opening and the two holes provided in the board to secure it. Put a strip of double face foam tape under it first.
Thank you, but I can't claim any credit, except maybe for reading comprehension, because your instructions were concise and complete. And I've never soldered anything more complicated than a guitar cable back in the garage band days.
The inductor has a piece of foam tape under it. The only cable ties I had on hand were too short, but I'll get that secured before I mount it in the cab.
Yes, probably, and C3 should be 1.5 mH, but hold off on all that 'til I get the measurements into crossover modeling software next week and hone in on the optimum values for you. I'll be posting all of that in "Flex Your Mettle" on the PE Tech Talk forum.
In the meantime, it appears to be playing enjoyably for you; we'll just make it even better, is all.
That's great, I'll look for that. I was lucky to get it to this stage, because for the next two weeks, I'll be too busy to touch it.
The best course would be to take the one you have to a cabinet builder for replication. According to Planet10, above, there are some discrepancies in the Jensen plans....
You won't have to move the woofer down very much to optimize that, looks like. It ALMOST fits already.
Two of these would probably result in my eviction, or a new career renting them out for a PA. This thing is by far the most efficient speaker system I've ever had. Way powerful, my ears are ringing. Good thing it sounds good at low volumes too!
The cutout for the woofer is 8 1/2 inches from the top edge. Close, but no cigar. A new baffle will at least make it easy to go back to the old setup if I want.
+2
[This is really fun stuff...!
AGREED!
Oh, definitely! It already sounds gorilla-sized--in the corner it will get the whole damn building singing along. My neighbors better like my taste in music...
The delay is that the only available corner is occupied by a Fender Rhodes piano, an old accordion, a Fender Princeton amp--I call that corner the "pawn shop" section of the living room. I won't have time to move that for awhile--starting tomorrow I'm inundated by family stuff that stops the hi-fi fun for about two weeks.
Thanks for that link--I'll be looking at that later. Looks like that guy has one of those JBL Hartsfield lenses in that one. We were talking about the retro thing, and I was leaning toward an Altec 811, but the QSC Waveguide is easier to find and cheaper. But I will try that option when I find a real bargain on an 811.
It's kind of cool to think of having a cab from 1952, a woofer from the 70's, and complete 21st Century tech on the HF. It sounds fooking awesome.
Note: 2220H is one of the JBL woofers having inverse polarity:
http://www.jblpro.com/catalog/support/getfile.aspx?docid=241&doctype=3
Next time you open it up, reverse your connections to the woofer terminals, i.e., your red lead (+ on the circuit board) to the woofer's black terminal, and vice versa....
Way ahead of you, thanks to... YOU. You mentioned some JBL woofers having inverse polarity in your intructions, so I was looking at those specs just before I wired up the LF.
This woofer is a 2220A, JBL only has specs on their site for the 2220H/J. Anyone know what the difference is?
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