4530/4520 horn lengths

[Jonathan W]

Is anyone able to tell me how come the 4520 twin 15" scoops are described as having a 13' horn length, whilst the 4530 single 15" scoops are only 7' long. They don't appear to be that different in cross-section. Is width a factor? Am I just missing something?

Also, while I'm here: Wouldn't a horn length of approx. 11'6" be more suitable, so as to bring the reverse sound-wave from the scoop back in phase with the direct sound-wave at the 150Hz crossover point between the two (150Hz wavelength at room temp. = approx. 7'8")?

Many thanks for any help that may be offered,
Jonathan Weatherill

[Hoerninger]

Some thoughts can be find here:
http://audioheritage.org/vbulletin/showthread.php?t=12773
___________
Peter

[subwoof]

I have built hundreds of each....the difference is the depth and height.

Lugging a loaded particleboard 4520 up a flight of stairs is a real joy so we were happy to see higher power amps + cones come along in the 80's so the SR buisness could switch to vented boxes.

But they sure pound out the lows for a dance club and are still preferred by installers if they have the room.

The 4530 is 24" deep and about 39" tall.

The 4520 is 30" deep and about 50" tall.

Both have added bases to allow casters, crossovers, etc to be mounted since they were popular as roll-around systems for theaters.

That added length really makes a difference below 50hz but neither goes below 30 or so without risking cone damge from unloading.

sub