You're welcome! Indeed! I began having serious 'exposure' beginning in '56 till this day in some ways, so plan on more than a few decades!
Here's an Altec technical letter from way back when comparing JBL shallow Vs Altec deep curvilinear cones WRT directivity:
Reading the paper (Thanks!) brings up questions, of course.
Re: History - Were 16" cones the largest used in 1986?
More importantly in your earlier post "It's about how you want to make it flex, i.e. control its polar response." , I thought that you were answering my question about smooth vs ribbed cone structure but the paper says they do not have any influence on directivity (at least that's the meaning I took from it) . Is that a debatable point?
Re: History - Were 16" cones the largest used in 1986?
More importantly in your earlier post "It's about how you want to make it flex, i.e. control its polar response." , I thought that you were answering my question about smooth vs ribbed cone structure but the paper says they do not have any influence on directivity (at least that's the meaning I took from it) . Is that a debatable point?
Woofer sizes have varied over the decades and don't recall any 16" ATM, only some Altec 15" in 16" frames.
Only WRT to how rigid (or not) the ribs may make it.
Only WRT to how rigid (or not) the ribs may make it.
Yes, The question about size was from casual interest because of the chart in Henricksen's paper making the change from driver to baffle at 16".
I have been looking for something that talks a bit about directivity relative to stiffness but can't find anything out there. Is it only talked about in big, expensive engineering texts? and more importantly so time isn't wasted on it , should I be thinking about it with regard to choosing a driver?
I have been looking for something that talks a bit about directivity relative to stiffness but can't find anything out there. Is it only talked about in big, expensive engineering texts? and more importantly so time isn't wasted on it , should I be thinking about it with regard to choosing a driver?
Good question, the Altec doc is the most instructional I've ever seen and WRT diaphragm design/construction, only what I've read in Harry Olson, etc., textbooks and 'exposed' to in a ~ day long instructional 'tour' of the Altec Anaheim Plant in '68 where by lucky happenstance they were developing a new ultra-wide range 15" (411A) for a new studio monitor (9846)/consumer HIFI (873 Barcelona) that was a departure from traditional W.E./Lansing/Altec woofers in that it had many very fine, closely spaced rings to get it to (hopefully) more closely track a 511 horn's complex polar response and by all accounts they were successful, but sadly was a financial disaster for a variety of managerial reasons, so relatively few of either model were ever built.
Regardless, if you're serious about audio reproduction playback in typical HIFI/HT apps, then 'tightly' controlling a uniform off axis power response is a priority to keep first reflections behind the ears/listening position and converted to a diffuse sound field behind it and why I've always had large horns/15" woofers on wide baffles toe'd in and a bookcase wall behind, though if I ever do another system it will be a DSL Synergy concept.
Regardless, if you're serious about audio reproduction playback in typical HIFI/HT apps, then 'tightly' controlling a uniform off axis power response is a priority to keep first reflections behind the ears/listening position and converted to a diffuse sound field behind it and why I've always had large horns/15" woofers on wide baffles toe'd in and a bookcase wall behind, though if I ever do another system it will be a DSL Synergy concept.
I've read about the 411A and Barcelona though never heard them, but all these details - the sheer amount of sophistication in something as apparently simple as a cone of paper being wiggled by a magnet is kind of mind blowing.
'Been listening to horns with 15's for about 15 years now, for the past 6 or so years to some that were loaned to me. They're going back to their owner soon which is what has me asking all these questions.
I'd be very happy with 15's in a 2 way horn system but have a pair of 10" mids that just perched on their cardbaord boxes sound good, . . . . a bit quicker than the 15's, so thought it worth trying them together with 15" for bottom 1.5 - 2 octaves, the 10" up to 750Hz and horn on top.
I started out thinking it wouldn't be that hard but every time I ask a question there's more to think about. Now it's Directivity ! : ) . . . . but if I understand the paper rightly, the cone drivers can be dialed in by the baffle size and driver placement on it.
and yes, then there's the Synergy . Even in a YouTube vid, very impressive.
'Been listening to horns with 15's for about 15 years now, for the past 6 or so years to some that were loaned to me. They're going back to their owner soon which is what has me asking all these questions.
I'd be very happy with 15's in a 2 way horn system but have a pair of 10" mids that just perched on their cardbaord boxes sound good, . . . . a bit quicker than the 15's, so thought it worth trying them together with 15" for bottom 1.5 - 2 octaves, the 10" up to 750Hz and horn on top.
I started out thinking it wouldn't be that hard but every time I ask a question there's more to think about. Now it's Directivity ! : ) . . . . but if I understand the paper rightly, the cone drivers can be dialed in by the baffle size and driver placement on it.
and yes, then there's the Synergy . Even in a YouTube vid, very impressive.
Last edited: