toddalin
12-03-2016, 07:04 PM
While having the woofers refoamed I decided to do further modification to my center channel speaker. This contains an AlNiCo 2235, 2420, and 2405, in ~6 cu ft and a W15GTi in ~4 cu ft.
http://www.audioheritage.org/photopost/data//525/medium/Stereo_007.JPG
The W15GTi had a ~14.5" long, 4" dia port and the 2235 had a pair of ~7.25" long ports. One was actually cut long and at an angle on the inside before, but I was running it blocked so the configuration would match the modified L200 cabinets. This port then had to be taken down to 7.25" and cut "round" to accept the 2.5" extension and flare.
The port for the W15GTi was extended to ~17.75" with a curved tube and flared to reduce the mach velocity. Also, a new 2" x 2" cross brace was added to deaden the inner and outter walls. (The inner wall is not parallel to the two outter walls to reduce standing waves.)
http://www.audioheritage.org/photopost/data//500/medium/DSC_00461.JPG
As noted above, the center channel had the corner port trimmed and both ports received the 2.5" extension flare making them the same lengths as those in my modified L200 cabinets. I also added the 2" x 3" cross brace to remove the resonance of the side panel and re-did the insulation.
http://www.audioheritage.org/photopost/data//500/medium/DSC_00451.JPG
While I was having the woofers refoamed, I also had a vintage, original 2420 tangential diaphragm put into the 2420 replacing the aluminum 2421 diaphragm. My L200 cabinets have 2420s with original tangential diaphragms which I prefer for their warmer sound. Again, you can see the tweaking that went into the crossovers.
http://www.audioheritage.org/photopost/data//500/medium/DSC_0034.JPG
Because the speaker sits almost against the wall, the L-pads for the mids and highs are accessed though the port. The switch on the left selects between the 2405 in the cabinet or the round jack on the back of the cabinet for a 2405 sitting atop the cabinet. This puts the components at about the heights as on the modified L200 cabinets.
The other switch selects the 2235 in series with the 100 watt non-inductive resistor. A switch on the back of the cabinet at the lower left corner selects the 2235 to run in parallel with the W15GTi when running in music modes on the Yamaha where the center channel is not being used (e.g., The Roxy Theater). The resistor balances the 2235's volume and removes tubbiness when used in this configuration. This really helps with groups like the Doors where Ray is doing left hand bass on the Fender Rhodes and just isn't "cutting it." A flip of the switch gives Ray's left hand substantial "weight."
http://www.audioheritage.org/photopost/data//500/medium/DSC_0038.JPG
http://www.audioheritage.org/photopost/data//500/medium/DSC_0043.JPG
Like I said, the Lpads are accessed through the port. A bit of Altec history. ;)
http://www.audioheritage.org/photopost/data//500/medium/DSC_00441.JPG
http://www.audioheritage.org/photopost/data//525/medium/Stereo_007.JPG
The W15GTi had a ~14.5" long, 4" dia port and the 2235 had a pair of ~7.25" long ports. One was actually cut long and at an angle on the inside before, but I was running it blocked so the configuration would match the modified L200 cabinets. This port then had to be taken down to 7.25" and cut "round" to accept the 2.5" extension and flare.
The port for the W15GTi was extended to ~17.75" with a curved tube and flared to reduce the mach velocity. Also, a new 2" x 2" cross brace was added to deaden the inner and outter walls. (The inner wall is not parallel to the two outter walls to reduce standing waves.)
http://www.audioheritage.org/photopost/data//500/medium/DSC_00461.JPG
As noted above, the center channel had the corner port trimmed and both ports received the 2.5" extension flare making them the same lengths as those in my modified L200 cabinets. I also added the 2" x 3" cross brace to remove the resonance of the side panel and re-did the insulation.
http://www.audioheritage.org/photopost/data//500/medium/DSC_00451.JPG
While I was having the woofers refoamed, I also had a vintage, original 2420 tangential diaphragm put into the 2420 replacing the aluminum 2421 diaphragm. My L200 cabinets have 2420s with original tangential diaphragms which I prefer for their warmer sound. Again, you can see the tweaking that went into the crossovers.
http://www.audioheritage.org/photopost/data//500/medium/DSC_0034.JPG
Because the speaker sits almost against the wall, the L-pads for the mids and highs are accessed though the port. The switch on the left selects between the 2405 in the cabinet or the round jack on the back of the cabinet for a 2405 sitting atop the cabinet. This puts the components at about the heights as on the modified L200 cabinets.
The other switch selects the 2235 in series with the 100 watt non-inductive resistor. A switch on the back of the cabinet at the lower left corner selects the 2235 to run in parallel with the W15GTi when running in music modes on the Yamaha where the center channel is not being used (e.g., The Roxy Theater). The resistor balances the 2235's volume and removes tubbiness when used in this configuration. This really helps with groups like the Doors where Ray is doing left hand bass on the Fender Rhodes and just isn't "cutting it." A flip of the switch gives Ray's left hand substantial "weight."
http://www.audioheritage.org/photopost/data//500/medium/DSC_0038.JPG
http://www.audioheritage.org/photopost/data//500/medium/DSC_0043.JPG
Like I said, the Lpads are accessed through the port. A bit of Altec history. ;)
http://www.audioheritage.org/photopost/data//500/medium/DSC_00441.JPG