Now This is a sub! Bertha...W bin - Page 3

ticknpop · 04:17 AM

The GSA system follows Richard Long's Paradise Garage system design with Levan/Bertha subs, either Ulitima rear loaded horns with 15 inches or what appear to be side mounted JBL 4520 or something similar to Waldorfs (which was Richard's 2x18 larger version of the 4520) although the one in this picture appears to use 15 inch drivers with a larger mouth on the rear loaded horn, double JBL 2395 horns (copies?) with JBL or TAD drivers, and JBL 2402 or 2404 tweeters. The Levan is a hyperbolic horn expansion for shortest length to the cutoff frequency - though it's still not small - the trade off is the high frequency distortion increases faster than other expansion rates, but as the Levan horn only covered 2 octaves it isn't a big issue. The Levan (named for Leroy Levan the best known DJ of the Paradise Garage) was the mouth expansion of the bass cabinet which Richard called a Bertha. A single 18 half height Bertha was an Emerald ( i believe was first used at Emerald City disco in New Jersey).

The drawback to the system is it's horn loaded except for the 200 to 1khz range where it's a direct radiator ( done better in bigger systems by Richard) and the phase cancellation where the rear loaded horn is out of phase with the 15 inch direct radiator in the low mid band.

I don't know if GSA is using a crossover similar to the RLA 3000/ 4000/5000 but expect he is.

ticknpop · 3rd July 2012, 01:45 AM

From further viewing of some GSA installation photos there is a GSA 3001 crossover which has the same functionality as the RLA 3000 - the RLA 3000 was build by Alan Fierstein of Acoustilog who did the room treatment of the Paradise Garage, and still services the RLA crossovers, but doesn't build new ones.

artscrafts14 · 4th July 2012, 08:50 PM

I finally was able to open up the back of the Bertha today. It has two large subwoofers. The numbers on both are 18016 and 67-8525. I want to thank you for your help but most of what you are telling me is way over my head. I'm not into electronics/music systems. I just happened to acquire these and am going to sell as a group. But I'm trying to gather information so I kinda know what I'm selling. Thanks again.

27th June 2012, 03:49 AM	#21
ticknpop diyAudio Member Join Date: May 2005 Location: toronto	The GSA system follows Richard Long's Paradise Garage system design with Levan/Bertha subs, either Ulitima rear loaded horns with 15 inches or what appear to be side mounted JBL 4520 or something similar to Waldorfs (which was Richard's 2x18 larger version of the 4520) although the one in this picture appears to use 15 inch drivers with a larger mouth on the rear loaded horn, double JBL 2395 horns (copies?) with JBL or TAD drivers, and JBL 2402 or 2404 tweeters. The Levan is a hyperbolic horn expansion for shortest length to the cutoff frequency - though it's still not small - the trade off is the high frequency distortion increases faster than other expansion rates, but as the Levan horn only covered 2 octaves it isn't a big issue. The Levan (named for Leroy Levan the best known DJ of the Paradise Garage) was the mouth expansion of the bass cabinet which Richard called a Bertha. A single 18 half height Bertha was an Emerald ( i believe was first used at Emerald City disco in New Jersey). The drawback to the system is it's horn loaded except for the 200 to 1khz range where it's a direct radiator ( done better in bigger systems by Richard) and the phase cancellation where the rear loaded horn is out of phase with the 15 inch direct radiator in the low mid band. I don't know if GSA is using a crossover similar to the RLA 3000/ 4000/5000 but expect he is. Last edited by ticknpop; 27th June 2012 at 04:17 AM.

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3rd July 2012, 01:45 AM	#22
ticknpop diyAudio Member Join Date: May 2005 Location: toronto	From further viewing of some GSA installation photos there is a GSA 3001 crossover which has the same functionality as the RLA 3000 - the RLA 3000 was build by Alan Fierstein of Acoustilog who did the room treatment of the Paradise Garage, and still services the RLA crossovers, but doesn't build new ones.

4th July 2012, 08:50 PM	#23
artscrafts14 diyAudio Member Join Date: Jun 2012	I finally was able to open up the back of the Bertha today. It has two large subwoofers. The numbers on both are 18016 and 67-8525. I want to thank you for your help but most of what you are telling me is way over my head. I'm not into electronics/music systems. I just happened to acquire these and am going to sell as a group. But I'm trying to gather information so I kinda know what I'm selling. Thanks again.