• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Jensen Mystery Speakers

ronrico

ronrico

AK Subscriber
Subscriber
I've recently picked up a pair of "Jensen Professional Monitor Model B" floor standing speakers. I've done a Google search and have come up with nothing. Does anyone here know anything about these? They appear to be fairly well made with wood veneer cabinets and large (8" X 10") x-overs. There is an interesting driver on the back that can be seen in one of the attached pics. The back panel and the front baffle are molded plastic and the cabinets are ported. They seemed to put a fair effort into building these which makes me think they might be worth the effort to bring them back to life (re-foam/re-cap).
Any thoughts?
 

Attachments

  • Jensen monitor B speakers 004.jpg
    Jensen monitor B speakers 004.jpg
    67.7 KB · Views: 438
  • Jensen monitor B speakers 002.jpg
    Jensen monitor B speakers 002.jpg
    84.7 KB · Views: 240
  • Jensen monitor B speakers 001.jpg
    Jensen monitor B speakers 001.jpg
    64.3 KB · Views: 301
Register to hide this ad
I'm not familiar with those, but they look to be significantly higher-grade than most Jensen stuff of that era. Give them a listen!
 
:thmbsp: Restore em..they do have a crossover built in which means they should sound damn good...I am running a pair of Jensen towers (newer) that I installed crossovers in and different mids and tweeters..what a difference!!
 
I find it curious that I'm unable to find any info on these. I'm not even sure what time frame to place them in, '80s '90s?
 
These speakers are called "System B." They were Jensen's top of the line from about 1978-1982. They had a smaller cousin called System C that was a 10" 3-way like the L-100's. Very good drivers were used. The bottom two were made by Jensen (Rola), the third speaker was Audax from France and the super-tweeter covering freq. above about 12kHz is a Panasonic. The engineer who designed these was very picky (I was his boss). The system was designed to be very flat but unfortunately the bass sounded a little thin compared to speakers like the L-100's that had a 2-3dB bump just above F3. I think I can find a schematic somewhere, no promises. One caution. The front baffle is plastic and when they were manufactured the drivers were held in with wood-type screws. With a high speed screwdriver, the screw would melt the plastic on its way down and basically weld itself in. Don't strip the head if you're trying. I was not in charge of mechanical design or manufacturing and I cringe every time I think of this.

By the way, the picture shows the speaker on a small base. This is sort of the "b" version. When it originally came out, the enclosure was mounted inside an inverted "U" stand that would allow the angle to be adjusted at two or three positions. They were very expensive to make. I think your version was made closer to 1981. I left in 1980.
 
Last edited:
montecarlossfan said:
:thmbsp: Restore em..they do have a crossover built in which means they should sound damn good...I am running a pair of Jensen towers (newer) that I installed crossovers in and different mids and tweeters..what a difference!!
Click to expand...

Every speaker has a crossover built in, even if it's just a single inline cap.
 
Sam Cogley said:
Every speaker has a crossover built in, even if it's just a single inline cap.
Click to expand...

Quoting Reagun: "There you go again!" (Not you Sam, just wanted to say that.)

Every is a pretty big word in a world that includes "Full Range" speakers, basically a 1-way with no crossover. Unless you count the mechanical decoupling of the center of the cone at HF...
 
I appreciate the responses. jlovda, the info you have given is especially welcomed, any additional info you can provide would be great. You are absolutely correct about the screws holding the drivers to the baffles, they are very tightly bound in place and with great care I have been able to remove the woofer and midrange in one cabinet.
I'm curious about the rear facing driver, what is the thinking behind that?
 
PioneerGuy75 said:
Most since the 60s has been crap :thumbsdn:

Keyword....MOST!
Click to expand...

They apparently retained the ability to build some interesting stuff, even if they went into budget-brand hell for the most part. I know they still have classic MI drivers like the P10Q in production.
 
Here's a shot of the x-over, massive 8"X10". I imagine the caps will need replacing.
 

Attachments

  • Jensen monitor B speakers 011.jpg
    Jensen monitor B speakers 011.jpg
    118 KB · Views: 175
ronrico said:
I'm curious about the rear facing driver, what is the thinking behind that?
Click to expand...

It helped to increase off-axis high frequency dispersion when the speaker was placed a couple of feet from a wall. There was also a little marketing fluff involved. One BIG design mistake was the angled tweeter on the back panel. The angle added little but the tooling cost was simply incredible. They should have just used wood with a hole in the back.

I saw your picture of the crossover. Note the speaker protection relay.

I should note that I got my MBA in 1980 and left the world of acoustics forever.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom