Tempest Speakers
The LAT Tempest mini-monitor and Nemesis subwoofer are the realization of a dream that began over 4 years ago as our reference speaker had become approximately 25 years old. The previous subwoofers were replaced in 2017 so we were anxious to move forward to a newer and better mate. The previous models were a collaboration between LAT and Albert Von Schweikert.
I met Albert in 1994 and apparently, he “saw” himself at age 28 and was impressed with my basic knowledge of crossover design and REALLY impressed with my mechanical engineering and my unusual ideas. So, I became VERY lucky to have him offer to work on a design together. It was a 6.5” two-way with a Focal woofer and Seas aluminum tweeter. I built them to a crazy level of rigidity and a tremendous lack of resonances. So, I shipped them to Albert in Ca. and 5 months later, he shipped them back. They have been serving me ever since as they would stand up against virtually anything! Albert continued to offer guidance, and help with other Crossover designs, etc. as our friendship grew over the years. He guided me every step of the way in designing the massive NEMESIS transmission line subs I made in 2017. Not long before he passed, he knew I was anxious to update the Tempest with more modern drivers, an unusual cabinet design, etc. Of course, he asked what drivers I was intending to use, and I mentioned the 7” Eton driver from Germany and the Norwegian made SEAS aluminum/magnesium unit for my tweeter. He was very familiar with the woofer, but the SEAS tweet was very, very new at the time. He ran an analysis and mocked up my crossover design quickly with his latest design software and simulation equipment. In the final version, believe it or not, I only changed two small values of his componentry recommendations. That’s how good Albert truly was. He was such a kind and wonderful man, and I miss him terribly!
So, A bit about the design….
We are using a 12db circuit on the woofer and 18db on the tweeter resulting in a phase correct acoustic forth order result. The cabinet is vented with a tuning frequency of 44 Hz.
Internal volume wound up at .55 ch/ft. Which allows unbelievable bass down to around -3db at 47 hz. Efficiency is 88.5 db. The ultimate Frequency response is +/- 3db 48-22,000 hz. The speaker tops out at 40 lbs each.
The project starts and stops with the enclosure. HUNDREDS of hours went into the engineering of the cabinet. It is a laminated design with A grade Baltic birch plywood which is the undisputed leader in high quality plywood. A full 23 pcs of .75” ply go into the making of the cabinet. The front baffle is 3 sections thick and 2 make up the rear. 3 strong braces placed within the cabinet give it tremendous strength. The internal pcs are made up of 5 different internal makings (shapes) These are placed in a very strict order to allow the pcs to break up resonances to many teeny tiny resonances in lieu of a speaker’s typical 3-4 major resonances. The difference is quite audible! The shape of our baffle really allows the driver to be very much on their own with very few reflective surfaces.
On to the drivers….
The woofer is the wonderful 7” ETON Hexacone driver. Their proprietary sandwiched material made up of Kevlar, Carbon fiber, and a very strong but light resin adhesive, a ridiculously oversized magnet, and a cast frame. The 3 layer Hexacone is nicely detailed, yet warm sounding. Most drivers can't provide both detail and warmth, but the Hexacones always have fast and detailed reproduction, authentic staging, and uncolored sound. It is truly a reference driver and perfect parameters for our goal for a bass/midrange driver.
Albert and I have used Seas drivers now for knocking on 30 years. About 4 years ago SEAS created a truly hi end aluminum/magnesium unit with a titanium former and a textile surround making a HUGE improvement over its cheaper sibling the famed H1212 we had been using. The titanium former has 25% of the susceptibility to distortion due to heat at high listening levels. The SEAS Prestige Titan 27 became the clear-cut winner to pair with our ETON bass/Mid.
The Seas 27 incorporates an anodized aluminum alloy diaphragm with piston-like behavior throughout the audible frequency range. A sonomex surround is installed for low resonance and excellent mechanical linearity. The copper cap in the magnet system reduces distortion and voice coil inductance, resulting in a sound without colorization. Also, an optimized rear chamber and internal damping for a smooth and resonance free response is a major benefit of this latest metal dome from Seas.
The NEMESIS transmission line subs are designed to be used as the stands for the Tempest satellite speakers as well as bass performance down to -3db at 25 hz. We chose the wonderful Danish made Scan Speak aluminum 10” for this project. Its specs are nearly perfect to operate in transmission line. The t-line technology only has one flaw in our minds and that is, they must be large cabinets. As long as your room (or your wife) can accommodate them, you have the best in technology for really high-quality bass response. In a t-line design the bass response is allowed to go down to (on or very near) the resonant frequency of the driver itself. Also, the bulk of the bass coming from the mouth (the vent) in a t-line is in phase with the driver. In a traditional vented enclosure, the bulk of the output is out of phase with the driver.
We trust you will be as impressed with this reference quality speaker as we were. I seriously expect this speaker to serve us well for another 29 years!
Rest in peace dear Albert. None of this would have been possible without you!