A regular reader and friend of Speakerholic dropped off a massive pair of JBL speakers a few weeks ago the JBL CF150.
These giants stand 36" tall and are 18" wide and 16" deep, it takes two people to move them. These JBL's sport a massive 15" woofer, a 6.5" midbass driver acting as a mid range and a dome tweeter. The efficiency of these speakers are 98db at 1 watt which makes them pretty loud.
These are not your typical "Wife Friendly" speakers and nor do they work in a 700 square foot condo, these speakers overpower everything but the biggest home theatre or man cave. I have these in my room that measures 14'x18' and there is no way this space can do these speakers justice.
The CF150 was circa mid 1990's and retailed for about $1000 a pair. I don't really know where these fit into JBL's line up or what the marketing was behind these speakers.
When I got these giants and listened to them for the first time a distinct resonance was coming from one of the speakers, the woofers are so big and powerful that they rattled the poorly braced and dampened cabinet apart.
When I pulled these speakers apart I found them to be an odd mix of really well made components yet a poorly made cabinet. The 15" woofer is a typical high end JBL cast basket woofer, the crossover used poly film capacitors yet the cabinets had virtually no bracing and zero dampening material internally, it was almost like they started to cut corners to reach a price point.
The game plan was to reinforce the cabinet and add internal dampening material to beef up the cabinets. A drop by a friends upholstery shop and I cut the wood to size and got the poly fill material, lots of it.
The first thing I had to do was apply a bead of glue on every corner in the cabinet, after that dried I glued in bracing material on the side of the cabinets and on the front to rear baffles.
Next was the sound dampening material and lots of it.
Extra material also went into the midbass enclosure as well as a seal around the woofer.
These speakers are re assembled and I have had the pleasure of listening to them but before I get to the sound here a few pictures to see the scale of the size. First the JBL versus a Pioneer HPM-60.
The JBL in the room versus all my other speaker along a wall as there is no where else to put them.
The sound, typically JBL with very full bass, I am running them off the Myryad T-40 amp which is mid range forward and these speakers have a surprisingly good sound stage. I find them to be very open and airy not unlike the Dual CL390's. One can hear all the different positions of the instruments with a convincing three dimensional sound stage.When switching between speakers I had to adjust the volume for the JBL's efficiency. The 15' woofers really added a nice full bottom end that speakers with an 8" to 10" woofers can not do.
I tried the JBL's out with the Sherwood S-8250 CP receiver which has a heavier bass and laid back mid range and the speakers did not sound nearly as nice. I also believe the higher dampening factor in the Myryad has better control over the speaker.
When listening to Pink Floyd the wall at 40% volume you felt the music like in a concert hall. I bumped the volume up to 50% but my listening space is not optimal for those volumes and I am sure the neighbors were annoyed. These speakers need a large space to let them run. One other note is spikes in the corners of the base would help isolate the speaker from the floor and tighten up the bass, an extra 4 inches of elevation would help out.
These speakers would shine in the right large room along with the right 100-200 watt amp, they certainly shined in my small space with a mid powered amp up to about 40% volume after that it just got to loud for the space.