It’s good to see John is back up and running! 8)
He has asked me to post some build pics of my system using his Lambdas. I can’t compete with the studio monitor post and the awesome wooodwork that John did, but we are very happy with what we have. 😀 I’ve also posted pics of his new 12 spoke passive radiators which will become his standard production. I’ve loaded the 1050 gram PRs to 1800 grams for the subs.
These are the TD12S with phase plugs crossed at about 750hz with the dual Scan Speaks picking up the midrange work and the Hi Vi Research RTII isodynamic planer tweeter. Running the 2 Lambdas in each main and the Scan Speak mids in parallel, this gives me a 6 db gain in overall output and the performance is absolutely outstanding with two channel music or full surround. I’ve also enclosed a picture of the crossover I built, using the design that John worked up for me. No one who has ever been here to audition my system has heard any better audio in a home. I whipped out my db meter last night during Eric Clapton’s Crossroads concert and was pegging 115 db with more headroom to go. Very clean and undistorted.
I have built a second sub identical to the one in the bottom picture and have them stacked, working as a single subwoofer. They are corner loaded for room gain. I will be replacing my Parts Express passive radiators with John’s 15″ 1050 gram passives in the subs. At 1800 grams, the new passives should bring my tuning frequency in each of my subs from 25.5 hz down to 20 hz, (on paper). I should see a bit even lower response than the modeled tuning frequency due to the softer suspension in John’s PR’s. At full cone excursion, I will see a response just below 13hz. I sure would have bought them from John if they were available from him when I needed them! All 9 grill frames are at the upholstery shop for new black audio grill cloth replacement.
I’ve already started rebuilding the mains again. I’ve had the numbers run with WinISD on the lower Lambda section with the ports, and I’m currently tuned at 30.04 hz., which is higher than what I thought I had. I have cut the new passive radiator holes in one of the mains and will be putting PE passives in, replacing the ports. I think I may have had some port resonance, and according to Vance Dickason’s Cookbook, “an improperly placed port could multiply resonances by as much as 10 times”, so it was a no brainer to eliminate them and use the PE passives I already had with John’s new ones on the way. Mike P.’s WinISD models out the Lambda section to 23.8 hz. at 6 cubes and dual TD12s with the 4-1100 gram PE radiators. I’m also going to have to rebuild and re-laminate the baffel for the Lambdas because the patch job where the flared ports were installed will look very undesirable.
This is why I DIY. I enjoy constantly upgrading my system.
Please check out my last post showing the new install of the mains with the ports removed and the new 1080P Mitsubishi setup. The center speaker is now under the TV, tilted up to the listening area.
Cudos to John Janowitz and Mike P. for all of their help.