If a fella didn't know better, he might think the 411 is a cousin to the LE-14 and LE-15, they're nearly family in terms of performance/parameters.
I had the same reaction,AB. GM changed my mind.Originally Posted by Altec Best
Your neighbors called. They like your music.
If a fella didn't know better, he might think the 411 is a cousin to the LE-14 and LE-15, they're nearly family in terms of performance/parameters.
Not all vegetables make good leaders.
What was Altec thinking?
That's what I said when I restored my 9846s. Getting the 411 to match with the 511 seems
to be a challenge. Bi-amping with a 12db active slope and using the 30904 attenuator was the best for me.
I used 24db for a while but I could identify a dividing line between the horn and woofer. Once that idea
got in my head, it wouldn't go away until I changed it. Spacing your horn farther away will make it worse.
Do your units have the 30904 attenuator and the 21597 diaphrams?
The 21597s are delicate and crossing them at 800 helps protect them along with the attenuator..........................
I believe an ex-JBL guy did the design work while at Altec.
Your neighbors called. They like your music.
Was it Bart Locanthi?
Didn't i read somewhere recently that he did a short stint at another speaker manufacturer(Altec?) between his JBL tenure and his work at Pioneer/TAD?
EDIT: I had to have a bit more caffeine and a session with the logsplitter, then it came to me. Cetec/Gauss is the company Mr Locanthi worked for briefly before going to Pioneer/TAD, not Altec.
Last edited by bowtie427ss; May 9th, 2013 at 02:04 PM.
Not all vegetables make good leaders.
Greets!
The 411 was designed to meet the performance needs of the times same as any product, yet still somewhat backwards compatible and why it?s suitable for a large vented alignment, especially one driven by a high output impedance that dictates an acoustically large cab tuned to Fs if max LF BW efficiency is to be realized.
To mod the 878 cab for a 511, the easiest is to seal off the horn cutout and flip it upside down to keep vertical acoustic offset to the practical minimum with the 511 on top. For this reason, just perching the 511 on top isn?t technically a good plan unless the listening distance is far enough away for the horn to appear as being very close acoustically to the woofer.
Perching the 811 on top of the 511 has some merit in theory as Cal Weldon has done on top of a pair of A7 cabs. Since the horns must be attenuated so much due to the 411?s relatively low efficiency though, the extra XO point may not be worth it unless you need the extra HF horizontal dispersion it affords.
Since the cab will be a bit larger [net Vb] acoustically, it will have a slightly lower Qtc [higher F3], so will in theory have a bit ?tighter? LF response, though without an A/B comparison it may not be obvious due to the room?s acoustics contributing so much to a speaker?s perceived tonal balance.
?Textbook? 2nd order slopes are a good compromise between complexity, power handling [driver protection] and distortion plus long before TD alignment became the ?next big breakthrough? in speaker design it was found that even order slopes makes it easy to design in time alignment within the ? WL standard empirically determined early on in multiple speaker system design by simply reversing the HF driver?s polarity, though of course with digital delay one can easily/quickly align most any oddball/extreme offset layout, slope order.
The big problem though is that for it to work properly acoustically there must be at least an octave of ?flat? BW on either side of the XO point, which severely limits its location without carefully matching components and/or using some form of EQ.
WRT woofer/horn combos, there?s the added problem of the point source [woofer] having a 90 deg phase lag Vs a compression horn?s, so this must be either accounted for by proper vertical offset and/or use an odd order on the horn and even order on the woofer.
With the Rane then, you should have no trouble dialing in an XO, horn CD EQ, timing offset [TD] that yields whatever horn vertical lobing offset is required to ?beam? the HF to your ear height/whatever, so no need to be limited to any ?textbook? solution, though spacing it up off the floor as much as practical to keep from needing excessive lobing is normally a good plan plus getting the woofer up to chest height can add a bit of the visceral impact of a live event.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
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