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Old school... TacT RCS2.2X / S2150 / TACS software

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Hi all. I've been an audiophile most of my life but sort of took a break the past few years after moving to a new house. I finally got around to finishing the home theater and got my gear hooked up once again. I guess it is obsolete but I still love it and am excited to be able to enjoy it again. I found a lot of great info on this forum so thought I would share, as my experience in DSP and computer audiophilia probably predates many others here.


Speakers are the Nola Grand Reference, an older version. The sub towers are basically four individual, stacked 12" ported enclosures. The main channels have a short line array of nine Raven R-1 ribbons and seven Vifa M13Mi-08 alnico magnet midranges operating as dipoles. Four 8" Seas Excel W22EX001 magnesium cone woofers, two above and two below flanking the line array, are each in individual sealed enclosures. Carl Marchisotto supplied the loudspeakers with outboard passive crossovers using first order electrical filters, as well as a Dalhquist DQ-LP1 electronic low pass crossover for the subwoofer amp; I don't use them and rather opted for a DSP alternative. Utilizing the steep crossover slopes available with DSP, I was able to make the subwoofers sonically (if not visually) inapparent. Dynamics improved considerably, which I attribute to rapidly rolling off the Ravens' output below their crossover point.


Amplification chain is a complete TacT Audio setup with RCS 2.2X digital preamp and four S2150 power amplifiers. Each piece was modified by Aberdeen/MauiMods with upgraded power supplies, passive components, and internal cabling. I use the 2.2X only as a master volume control and digital signal distribution hub, except during the setup process when it is used for taking measurements needed for room/driver correction. Each amplifier accepts a full range PCM digital signal (up to 24/192) which is then transformed in real time using a custom filter that includes crossover, room/driver correction, target curve adjustment, parametric EQ, and time/phase compensation. Finally, direct PCM>PWM conversion is performed, with volume controlled by manipulating voltage on the rails; there is no attenuator in the actual signal path, nor are any bits lost to reduce level. Each driver group is connected directly to its amplifier. The designer (Radomir Bozovic aka 'Boz') was truly a genius and way ahead of his time. Sadly he lacked comparable business and marketing skills, and TacT is long gone. Fortunately the TacT gear seems more reliable than his subsequent 'Boz' line which I never bought into.


Power is supplied by a PS Audio P10, which just recently replaced a Running Springs Audio Haley. I was hesitant to purchase it, having had a lot of trouble with a P1000 regenerator I bought many years ago, but this unit seems fantastic and the TacT gear really seems to thrive on the very clean and steady 120Hz. Power cords are all carbon ribbon from Michael Wolff, who sadly passed a few years ago. AES/EBU and S/PDIF digital links as well as speaker cables are Acoustic Zen.


My source has been a modified Slim Devices Transporter, one of the original ones with the knob. I actually just ordered a replacement for it, an Aurender N10 in black. I chose it based on the reputation of the S10 it replaces and the W20 positioned above it. Also it happens to be a perfect cosmetic match for my TacT gear. I also was considering the Bryston BDP-2, Ayon NW-T, and Aurelic Aeries but I talked myself into spending the extra coin for the N10, which is a brand new model that should be a great match for my setup. I also have a Fusion Research OMS3 installed in a separate equipment rack (with a complete Elan G! home automation/AV/security system), its two analog outputs supply the 15 zones of home audio but I routed its S/PDIF output to the TacT gear using a long in wall RG-6 cable, also buried in the concrete. Unfortunately I have to use RCA and BNC adapters for it but it works okay and this source is primarily for stored compressed files, Pandora, Spotify, etc. anyway. I will load my FLAC and hi-res library on the N10 and have it backed up on NAS.


Here are some photos of the system. The four pairs of speaker cables are very thick, so I channeled the concrete for them. Sound absorbing material is in place behind the fabric, so the room has some live-end, dead-end features. It helps with high frequency reflections, but does nothing in the modal range of course. The big glass box up front is a 450 gallon reef aquarium that should be getting filled soon, plumbing is almost complete. For movies, a screen drops down in front of the tank and a Denon HT receiver and modest RBH Sound 7.1 surround system take over the sound... obviously I am more picky about my music then my movies!


The project is not quite done, I'm waiting for baseboards to be installed and a custom equipment rack that will be disguised as a coffee table. So the equipment will be staying right in front of the sofa, just the RBH center channel will above the table top. The Transporter will be sold or relegated to my office system.






















These are the filters I created and programmed into the amplifiers, using free 3rd party software called TACS. These days the trend seems to be to do this on the source end using products like AudioVero's Acourate...



Sub filter:




Woofer filter:




Midrange filter:




Tweeter filter:




Final measured response at the listening position (middle graph):




And this is the old tank, which i pulled out as it was a maintenance nightmare in the new house. Plan this time around is to ultimately have about the same amount of livestock in twice the gallons. I look forward to listening to music while watching live action in the tank.




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  • 2 weeks later...

Great measurement! I dig your fish tank as well. Would you know if the fish are bothered by deep bass sound waves? Too bad Tact went belly up. Boz sure was no marketing man, as that was Peter Lyngdorf. They couldn't agree the company split, and with an engineer running the operation, well, the writing was on the wall.

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Surprising how often I am asked that question. The fish don't seem to care. The air-glass-water interface is not so conductive to sound, relatively little actually penetrates into the water... think of how much outside noise you hear when underwater in a pool, as an analogy. And not even these subwoofers can come anywhere close to a whale, their low frequency vocalizations can travel 3,000 km through the ocean!


It is indeed a shame about TacT. Boz is a genius, too bad he couldn't work with Peter Lyngdorf who had proper business skills. Things went downhill fast once they parted ways. I still have faint hope that Boz will jump back in one day, I know he had designed a RCS4 and some other products but decided to not go forward with them. Rather I believe he now is manufacturing some commercial lighting equipment... what a waste :-/

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They couldn't agree the company split, and with an engineer running the operation, well, the writing was on the wall.eZhjxA




Peter seems to have done quite well, on the other hand. Apparently he did not have rights to Boz's room correction intellectual property, so he developed his own variation e.g. RoomPerfect. I was recently reading about the Steinway-Lyngdorf Model LS which is quite similar to my setup, with Equibit amps incorporating DSP crossovers, correction, target curve EQ, etc. It goes for about $250k as a compete installed system - clearly he knows how to succeed in business :)

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  • 3 months later...

A colleague has been using TacT digital preamp and 3 x power amps for over a decade, with a pair of TacT 2-way speakers a pair of Lyngdorf designed passive 10" subs. He has been steadily improving the sound over the years with countless tweaks, including linear PS for the preamp, but recently he is seriously considering moving on from the TacT gear. His main complaint against TacT is its use of ASRC chips at the inputs. Several years ago I helped him replace the Analog Devices ASRC chip in his TacT preamp with a TI pin-compatible chip and the sound improved noticeably, but with advances in DAC and streaming audio, he is now viewing the ASRCs in both TacT preamp and power amps as possibly the weakest link in this setup.


As an alternative to the TacT stack my colleague has recently started experimenting with an Auralic Aries driving a Vega DAC (w/ a Lifatec Silflex Toslink cable) driving a Taurus Mk II preamp/hp amp (I have exactly the same Auralic stack driving HD 800 balanced headphones). A Behringer DCX2496 is used to do crossover, time alignment, level matching and EQ. A Dayton Audio OmniMic v2 was used for room measurements. The amps are a pair of Acurus DIA100 as placeholders, and my colleague is eyeing Benchmark AHB2 amps and has an American Audio box on order to replace the Behringer. He also picked up a set of KEF LS50 speakers. Since the LS50 don't support bi-amp but have time-aligned tweeters and woofers, he does bi-amp for LS50 and the passive subs.


Compared to the TacT stack, the new setup delivers more relaxed sound with wider and deeper soundstage and accurately sized and placed instruments and vocals. The sound was more organic overall and there was less digital grain. These results were quite surprising to us initially, especially since there is an additional ADC & DAC in the chain (inside the Behringer) so counterintuitive given the "less is better" thinking. What this suggests is that the first DAC (receiving from renderer/streamer) is far and away the most critical. The Vega DAC in Exact clock mode does a splendid job here. Redbook 16/44 content sounds almost indistinguishable from 24/96 or 24/192 high-res. From there, even the ADC-DSP-DAC manipulations did not compromise the SQ to any significant degree. We did compare the sound with the Behringer taken in and out of the chain just to be sure. The benefits of the Behringer outweigh its drawbacks. Ditto for another friend using tube amps to bi-amp a pair of ProAc speakers. Time aligning the ProAc tweeters with its woofers made a huge improvement.


My colleague will likely be selling his TacT stack in the near future. He'll be doing a home trial of Benchmark AHB2 amp next month, after the American Audio box arrives. I've been eyeing a Lyngdorf TDAI-2170 amp for my own setup, but suspect that it too uses an ASRC chip for its inputs. What we'd love to have is an all-digital crossover/time alignment/EQ box that does NOT employ ASRC chips. It will ideally support up to 24/384 PCM as inputs and outputs so its DSP has got to be uber powerful. Then 2 or 3 sets of DACs and amps will be used depending on bi-amp or tri-amp.

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