Altec A-7, JBL 4530, wich commun JBL driver to use?.

[peteracing]

Hey guys, if i wanted to build a VOTT A-7 AND a JBL 4530, and then choose witch one is a keeper,
witch one single choice JBL driver would you use? 2205? 2225?...
Could it be compatible with a 13ft horn (like a 4520)? like if i built a single woofer 4520...
Food for thoughts here as i'll explain later :D...

[Lee in Montreal]

A7 and 4530 are completely different beasts. What will you use the cabinets for? How many woofers do you have? A rear loaded horn with 13ft pathway would have a fundamental 1/2 wave at 42Hz and 1/4 wave at 21Hz and phase cancellation at 63Hz. Perhaps you could build a front loaded horn instead if you wanted to go higher than 60Hz. Build a single Bertha or similar. BTW How big is your spce?

[peteracing]

Hi there Lee!.
I have 2205 frames, so i can recone as...
It's more of an idea i had yearssssssss ago, doing a frankenspeaker by adapting a front horn a la A-7
combined with a rear horn loaded a la 4520/ 4530...
It's for my 24/24' studio :D yes i know, it's rather overkill but i seem to remember visiting a friend of yours
that had a pair of 4520's in a smaller room and it kic ked a ss!!!

[Lee in Montreal]

Mixing front and rear loading in the same cabinet is a bad idea because of the cancellation of scoops.

Lee

[peteracing]

Lee, am i wrong in assuming a 4520 blh is 13ft long?. Then are you saying that it's a bad design?.

So back to my original question; witch JBL driver would suit both a A-7 and a 4530?...

[Lee in Montreal]

4530 is 7ft (40Hz cut off, 80Hz fundamental, 120Hz phase cancellation) = great kick, tight bass
4520 is 8ft (35Hz cut off, 70Hz fundamental, 105Hz phase cancellation) = less kick, great round bass

You can build your bass foundation with a 4520, crossed at 80/90Hz (18db / 24db) and add an A7 on top for its superb upper bass and great medium range. The A7 is quite efficient from 100Hz up, but lazy below. But the problem with this set up, is that the lower bass will be 8ft "behind" the A7 because of the horn length. Therefore, if you do not intend to play loud all the time, perhaps you could replace the 4520 scoop by a bass reflex enclosure with a single 18" driver. For home use I would use a 2245 woofer...

[peteracing]

Ok, sorry Lee, thought that the 4520 were longer.........