High Efficiency Speaker Asylum

Posted by munna on February 21, 2007 at 08:04:29

In Reply to: Cabinet recommendations for Altec 515 drivers welcome. posted by Addicted on February 20, 2007 at 04:47:10:

Hello

i have played around with altec horns and woofers for some time and here are my observations.
1. Since you have parts you want to build from, I wont suggest
the Model 19. But try to hear this so you can use it as your
reference on balance. Your A5 when done right
should have this balance but with better midbass.
2. the 500 xover point lends naturally to a midrange
emphasis which is a bit hard to balance. i found the 800 point
easier to work with.
3. A5 (also called 825 cabinet) maybe the easiest way to get good
sound for an altec wooofer (be it 515 or 416). Its got
a magic midrange. It would be wise to make this your starting point
(it might be your end point too). In the presence region of
250-800 its
very hard to beat. Note that most of
the Edgarhorn TitanII and other
bass horns are better in the 80-200 region but they dont
really compete with the A5 from 250 upwards. Note that from
150 downwards, the A5
has a 'shelved bass' and needs to be augmented by some extra
woofers or subwoofers (pair of large 15 dbl woofer boxes
would work nicely and are more natural-sounding
than a pumpy-subwoofer)to get better sub-150 bass.
4. The 288c is a great compression driver. but most of
the horns that fit it
are too big for ordinary rooms. In my experience the
288c is at its best in
need a huge room (greater than say 20x30x10). the 288c with
its big
horns needs 3 woofers a side to balance it out (2 per side in an
a2 is not enough --- still gives too much midrange oomph).
5. The Hirago xover with its notch filter
is a worthy atttempt to tame the 288&its horn.
but i found it taking away too much music.
i got much better results by going to a jbl 2440 and using
a smaller domestic-friendly horn. for examples, you can choose
from jbl2397 / bruce-edgar 500 saladbowl horn / rca-fans conical
700 alumminium horn. All of these are easier to get right than
the big altec horns as well as being more practical.
6. If you want to stick to altec, I suggset the
smaller altec horns and altec 1" compression might be
a better starting point than the 288c (note that the
smaller altec horns
and drivers are a bit spitty compared to the jbl 2440 (great
by any other standard)
7. I would recommend the Model 19 crossover (N850? N12850?). These
are 8ohm xovers but can be used with great effect. altec made
a variety of xovers -- be ready to experiment. i did not have
much luck with the jbl xovers.
8. if you go with jbl 2440 you will have to add a tweeter & cap to
it (fostex is a good start point here).
9. be prepared for some amount of experimentation (2-100 years?)

regds
munna