You're welcome!
Well, if by 'optimistic' you mean it doesn't show all the little irrelevant 'squigglies', you're right, but otherwise they provide all the data necessary to create a successful design. Note that these were done for speaker designers which included approved Altec installers, not for marketing, DIYers, etc. unless you were someone like me that asked so many technical Qs that you were added to their in-house tech bulletin mailing list. Also, at the time these were done they basically owned the prosound/cinema market, so no need to be 'optimistic' and as time progressed they resisted the urge to compete with JBL and others that typically used a fat line trace and one octave smoothing to make them seem superior to Altec.
Regardless, the times and the personnel that would use these allowed for a certain amount smoothing, so the BWs below 500 Hz and above 2500 Hz are 1/3 octave smoothed and each plot in the series were smoothed just enough in the 500-2500 Hz 'telephone' BW to make them easy to compare, i.e. no set smoothing value, though from experience it was very little with the various Altec horns I used. Note that these were done in accordance with the then current IEE standards (1948).
Anyway, back when I was most active in this hobby, such test gear was only available to businesses or DIYers with 'deep pockets', so any measurements I did were with a calibrated SLM, signal generator and plotted on log paper and since I was basically in a DIYer's 'vacuum' without enough prescience to even consider the possibility of ever owning a powerful home computer that would allow me to communicate with like minded souls around the world, much less measure/create such detailed plots ya'll take for granted and seem to 'live and die' by, there was no perceived need to save what little I did do, much less save all the magazines, product cut sheets, patents, etc. I read.
Later, I did manage to get a decent 1/3 octave RTA, but with no printout capability and still ~15 yrs. before I had a computer bigger than my hand, all I could do was use the peak hold feature and write the info down.
If there's any polar plots by others, I'm either not aware of them or don't remember.
GM
Well, if by 'optimistic' you mean it doesn't show all the little irrelevant 'squigglies', you're right, but otherwise they provide all the data necessary to create a successful design. Note that these were done for speaker designers which included approved Altec installers, not for marketing, DIYers, etc. unless you were someone like me that asked so many technical Qs that you were added to their in-house tech bulletin mailing list. Also, at the time these were done they basically owned the prosound/cinema market, so no need to be 'optimistic' and as time progressed they resisted the urge to compete with JBL and others that typically used a fat line trace and one octave smoothing to make them seem superior to Altec.
Regardless, the times and the personnel that would use these allowed for a certain amount smoothing, so the BWs below 500 Hz and above 2500 Hz are 1/3 octave smoothed and each plot in the series were smoothed just enough in the 500-2500 Hz 'telephone' BW to make them easy to compare, i.e. no set smoothing value, though from experience it was very little with the various Altec horns I used. Note that these were done in accordance with the then current IEE standards (1948).
Anyway, back when I was most active in this hobby, such test gear was only available to businesses or DIYers with 'deep pockets', so any measurements I did were with a calibrated SLM, signal generator and plotted on log paper and since I was basically in a DIYer's 'vacuum' without enough prescience to even consider the possibility of ever owning a powerful home computer that would allow me to communicate with like minded souls around the world, much less measure/create such detailed plots ya'll take for granted and seem to 'live and die' by, there was no perceived need to save what little I did do, much less save all the magazines, product cut sheets, patents, etc. I read.
Later, I did manage to get a decent 1/3 octave RTA, but with no printout capability and still ~15 yrs. before I had a computer bigger than my hand, all I could do was use the peak hold feature and write the info down.
If there's any polar plots by others, I'm either not aware of them or don't remember.
GM
I imagine that any of them will sound good to me. I can barely make heads or tails of these graphs, but I'm not new to audio, just this level of DIY. I'm used to working with speakers that are just there in the studio: JBL 4311s, UREI Time-aligned, the dreaded Yamaha NS10s, Minimus 7s and Auratones. At the home studio I have a pair of Adam A7s, and my home stereo has been based around a pair of JBL 4311s I bought 30 years ago.
Like your picture of the Altec, that's what I have! Well, except that I have replaced the 511 horns with big multi-cell horns. =)
In your place I'd get the QSC horn, Selenium driver and the 2000Hz crossover from Parts Express + an L-Pad. (get the 50 watt L-Pad). That will get you started. Then the fine DIY crew here can design a real crossover for you. You are quite correct, the crossover can make or break the speaker.
But it won't cost you much to get up and running. You can play later. Rubber Soul is waiting Wilber....
In your place I'd get the QSC horn, Selenium driver and the 2000Hz crossover from Parts Express + an L-Pad. (get the 50 watt L-Pad). That will get you started. Then the fine DIY crew here can design a real crossover for you. You are quite correct, the crossover can make or break the speaker.
But it won't cost you much to get up and running. You can play later. Rubber Soul is waiting Wilber....
It's the EconoWave PC board. PM for details.
YouTube - Rev Up Your Vintage Speakers, Econowave Style
YouTube - Rev Up Your Vintage Speakers, Econowave Style
Update
Well, I'm on my way, thanks to you guys. I have the JBL 2220 15" on the way, as well as the Selenium. I ordered a QSC Waveguide, and have another option to try out thanks to a generous person on this site. Still gonna keep an eye out for a bargain 811B, just cuz I like that old school look. The cool thing is that swapping things in and out, mix and match is going to be easy, because I doubt I'll bother with a cab for the horn.
So everything but the crossover and L-pad is on the way. I'm tempted to go with the suggestion to get the parts-express 2 Kz pre-assembled, but on the other hand, maybe I should try to get the crossover right from the beginning, and not be impatient. JBL recommends no higher crossover than 1200 for the 2220, and Selenium says no lower than 1500 for the horn driver, so a 2 Kz crossover might be pushing things a bit, yes? Zilch, I'm reading your threads about the Econowave projects with great interest and medium comprehension--you've put a mountain of info out there on the interwebz.
I'm going to start sanding it down to get it pretty with a fresh coat or two of flat black enamel while I'm waiting for the goodies to arrive. I'll post more pics and keep everyone informed as to the progress. Keep the suggestions coming, I value all of your opinions.
Well, I'm on my way, thanks to you guys. I have the JBL 2220 15" on the way, as well as the Selenium. I ordered a QSC Waveguide, and have another option to try out thanks to a generous person on this site. Still gonna keep an eye out for a bargain 811B, just cuz I like that old school look. The cool thing is that swapping things in and out, mix and match is going to be easy, because I doubt I'll bother with a cab for the horn.
So everything but the crossover and L-pad is on the way. I'm tempted to go with the suggestion to get the parts-express 2 Kz pre-assembled, but on the other hand, maybe I should try to get the crossover right from the beginning, and not be impatient. JBL recommends no higher crossover than 1200 for the 2220, and Selenium says no lower than 1500 for the horn driver, so a 2 Kz crossover might be pushing things a bit, yes? Zilch, I'm reading your threads about the Econowave projects with great interest and medium comprehension--you've put a mountain of info out there on the interwebz.
I'm going to start sanding it down to get it pretty with a fresh coat or two of flat black enamel while I'm waiting for the goodies to arrive. I'll post more pics and keep everyone informed as to the progress. Keep the suggestions coming, I value all of your opinions.
GM, this isn't smoothed except for what smoothing effect gating has on things.
A graph like this would be much more helpful as it's easy to read and compare. I know you've been in this game a long time, but with all do respect check out my signature for info on irrelevant squiggles. There's something to it.
Not a fan of applying too much smoothing to a graph. 1/12 octave is plenty IMO. Well, actually too much.
Dan
Here's a look at another sample of the model driver/WG with the on axis included and only out to 45 degrees.
5mS gate in line 6uF cap 1/12 smoothed:
A graph like this would be much more helpful as it's easy to read and compare. I know you've been in this game a long time, but with all do respect check out my signature for info on irrelevant squiggles. There's something to it.
Not a fan of applying too much smoothing to a graph. 1/12 octave is plenty IMO. Well, actually too much.
Dan
Here's a look at another sample of the model driver/WG with the on axis included and only out to 45 degrees.
5mS gate in line 6uF cap 1/12 smoothed:
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If you have the time, build the econo crossover. The Dayton thing was just to get you up and running if a better crossover did not show up immediately. But since it did, you might as well build it.
It can all be done with screw terminals, if you want.
Question for Zilch. What is R2 for in the HPF? All I can see is that it drops the level 2-3dB, but the L-Pad is there for that too. What is it doing that I don't see?
It can all be done with screw terminals, if you want.
Question for Zilch. What is R2 for in the HPF? All I can see is that it drops the level 2-3dB, but the L-Pad is there for that too. What is it doing that I don't see?
I used to think it was simple and that I understood it, but wasn't until I got it into PCD sim with the actual driver measurements that I could manipulate it reliably. The L-pad leaves the contour largely intact when adjusting the level.
Here is Wayne's tutorial:
http://www.pispeakers.com/Speaker_Crossover.doc
There's more info in his ART Pi Speakers forum....
By PCD do you mean Jeff Bagby's Passive Crossover Designer? If so that's what I used to double check myself. And I didn't see anything other than a ~2dB drop in overall level. That's why I was curious.
But I ran it again this morning with a better layout and now I see what R2 does. It prevents peaking at the low end of the driver's range. It's a damping resistor, of course!
Don't know why I didn't see that yesterday. Thanks.
But I ran it again this morning with a better layout and now I see what R2 does. It prevents peaking at the low end of the driver's range. It's a damping resistor, of course!
Don't know why I didn't see that yesterday. Thanks.
Will do. Nothing much to see today--I patched a few scratches and gouges with plastic wood and sanded that down. I'd like to go ahead and paint it today, but it's already gotten too hot (I'm in Palm Springs, CA, an area that was never meant to be inhabited by human beings). I could drag it into the house and paint it, but I don't really want to breath paint fumes all day, so I'll get up early mañana and start painting before my patio becomes The Devil's Anvil. I'm leaving it flat black (satin enamel, actually). I think it suits the whole "is it hi-fi, or is it a PA" aesthetic of the cab.
As I progress, I'll post pics. I ordered the PCB for that XO that Zilch posted, and I'm trying to find the right parts order from the hundreds of thousands of pages of info he has graciously put out there on the highways of the interwebs.
Yes, that!
I may adjust the values a bit to get the highest possible sensitivity out of the Selenium/QSC combo. It's sounding fine with a low efficiency reflex woofer presently....
The basic parts list is here:
http://home.comcast.net/~dnewma04/EconowaveBoM.htm
All come from Parts Express; values differ with variants.
Selenium D220Ti is the bolt-on version for use with the QSC waveguide....
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Another of what is surely to be a series of dumb questions:
Parts express is back-ordered on the Jantzen 0.60mH 20 AWG Air Core Inductors. For a couple of bucks more, I can get the 18 AWG version which is in stock. Is this an acceptable substitute?
Jantzen 0.60mH 18 AWG Air Core Inductor | Parts-Express.com
Wilberforce got a D in Electric shop because he didn't pay attention, nor did he get along well with others. His parents were concerned at the time. He remains under-educated and ignorant to this day, but his attitude has shown marked improvement.
Parts express is back-ordered on the Jantzen 0.60mH 20 AWG Air Core Inductors. For a couple of bucks more, I can get the 18 AWG version which is in stock. Is this an acceptable substitute?
Jantzen 0.60mH 18 AWG Air Core Inductor | Parts-Express.com
Wilberforce got a D in Electric shop because he didn't pay attention, nor did he get along well with others. His parents were concerned at the time. He remains under-educated and ignorant to this day, but his attitude has shown marked improvement.
That's what I thought, but as an official Noob™, I'll be asking lots of dumb questions. This is going to be like "Speaker Building for Dummies."
In other news, the cab is looking prettier today with just one coat of the satin black enamel. It wants one more coat tomorrow before it will pose for pictures.
And, the QSC Waveguide arrived today--talk about speedy shipping! It is a pretty thing, too, I like it.
And even cooler, a mysterious and generous benefactor from this site bequeathed me with not one but two Selenium drivers and a pair of dandy 10" round Dayton horns! I'm not usually this lucky, but maybe some of my good karma came back.
The PCB is on its way, and I just ordered the XO parts, along with a horn adapter so I can switch back and forth between the screw-on round horns and the waveguide. And yes, I will be all set when I eventually run across a reasonably-priced Altec driver and/or horn. I still have an urge to try an 811, but it can wait until I stumble across a bargain.
Still missing in action is the JBL 2220A woofer I got on eBay. Any day now...
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