Control1 driver redesign

[duaneage]

The Control1 uses a 4 inch woofer known by JBL as the C1003. It is a magnetically shielded driver that offers remarkable performance for it's size and price. The T/S parameters for the driver are very similar to the 115H except for Vas which is 1/2 as large. This is due to the smaller radiating surface of the driver and a price is paid in efficiency, about -3 db compared to the 115H

The Control1 cabinet is 122cu inches tuned to 65 hz through a 1 inch duct. I built cabinets that are 232 cu inches and tuned to 65 Hz. The duct fires rearward since such a small tube tends to whistle on certain notes. I used a Moderaunt-Short tweeter which is comparable to the 034 in performance but offers a little higher power handling. Interesting enough, if the C1003 is used in 680 cu inches and tuned to 53 Hz you get performance like this:

[duaneage]

My 4411s are great speakers but I wanted a little monitor that could be used up close and so I made these from treadmill walking boards. They are 3/4 inch thick and coated with 1/32" of melamine on each side for a great finish. I made these 8 years ago and originally had 035Ti drivers. But as good as the highs were they were not a good match for the C1003. The M-S drivers are matched well with these woofers. Cabs are 232 cu inches with a 1 inch duct at 65 Hz.

[duaneage]

Both drivers were at around 3.7 ohms at 4 Khz. What worked for these drivers after exhaustive listening tests was a symetrical network with a little L-padding on the tweeter. Simple and effective, the phase response is much better than I was able to get with the 035 Ti.
Values for the network:
L1,L2 .36 Mh
C1,C2 2.7 Uf
R1 1ohm
R2 10 ohm
Solen caps and solen perfect lay inductors used in construction. I made a custom PCB by etching a board and used 37/63 solder.

[duaneage]

Used with a powered subwoofer they sound outstanding. Imaging is the forte' of small speakers and these are no exception. They are not party speakers but sound real good up close and the magnetic shielding on the woofer allows them to be placed near a tube monitor.

[bigyank]

Good job!

Yank

[Titanium Dome]

What do you play when you're walking?

[duaneage]

What do you play when you're walking?

Good one. I get that a lot.

I got ahold of 14 walking boards, 2 feet by 5 feet long. I made many systems with them until I ran out of material. I've never found the same stuff since.

[duaneage]

I came across a pair of JBL G40 speakers from the mid 90's. These were forgetable HT systems with cone tweeters but the mid-bass driver was interesting. It turns out to be a cousin to the C1003 driver in the Control1.

I ran the driver through tests with the Woofertester 2 and found it had a lower Qts than the C1003 driver but the exact same frame and mounting requirements. Box simulations showed a flatter response with higher output and superior group delay values compared to the C1003 in the same enclosure. The cone is not coated like the C1003, and the magnet is larger and unshielded.

I will install one driver in and compare side by side. This should be interesting.

[JBL 4645]

There tough little loudspeaker, best kept within there technical tolerance levels because I’ve also noticed a little chuffing sound, from the port when pushed to lower frequency limits at high levels.

My centre back JBL control 1 surrounds have a nice frequency response with a warm depth in there sound, the sides’ similar due to the space there in, in the room.