2445J for midrange?

[Ian Mackenzie]

Giskard,

Are you able to simulate the effects of room gain with the un equalised sealed enclosure?

As a guess I was figuring with 12 db rolloff of a typical sealed box the effect of room gain could be adjusted by placement to give optimum extension without the group delay.

Ian

[4313B]

"As a guess I was figuring with 12 db rolloff of a typical sealed box the effect of room gain could be adjusted by placement to give optimum extension without the group delay."

Yes, I've mentioned numerous times about using room gain to effect and the sealed system is a "natural" due to it's shallow rolloff. I've mentioned boundary reinforcement, corner loading, 2 pi and 4 pi environments, etc. I've mentioned how 2245H vented systems don't necessarily need a whole lot of boundary reinforcement and how 2242H vented systems can use boundary reinforcement to great effect, etc., etc., etc.

One of the biggest problems with selling the old three-piece L212 system was in getting it set up correctly in a listening room for demo purposes. Dealers that "knew what they had" had L212 systems set up so they would knock your socks off and they sold them. Dealers who thought a loudspeaker sold itself and a room had no bearing usually had an L212 system stuffed in a corner and never moved a single one.

Basically one can place their system in their room either benefiting the decor of the room or benefiting the performance of the system. Most people naturally go for decor, whether that means "looking good" or "merely convenient". When someone mentions, for instance, that they owned 4343's and didn't think the bass response was all that great, I surmise they probably suffered from poor placement. I've heard the 4343 sound terrible first hand and I've heard the 4343 sound fantastic first hand, and both instances were solely due to the environment.

"Are you able to simulate the effects of room gain with the un equalised sealed enclosure?"

Yes, BB6P can do that. It's easier with cars because one can pretty much go with "12 dB/octave rise below 50 Hz". If one is real serious they can measure their room gain and plug that information into BB6P.

Anyway, I guess this is getting a bit off-topic. Sorry! I've posted the paper on why to use a 2" compression driver instead of a 1" before. Search for Technical Notes Volume 1, Number 8. I believe it is in the "Ultimate Large Format JBL System" thread.

BTW, Nice 4345 Avatar Ian!

[maxwedge]

Originally posted by Giskard
Just a reminder that any EQ added also affects group delay.

I was going to cut in the 50/80 range and bring it all up with amp volume. I think you said somthing like this dosn't effect group delay but you pay a price in efficency.

[4313B]

Right