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IRS-Beta
AllegroModsTm



A Tale Of Two Speakers



Unlike reviewers the world over who raved and lusted over the IRS-Beta and proclaimed it one of the best speakers of all time [then and now], I found them muddy at the bottom, lacking in energy at the lower-crossover region, and uneven and fatiguing at the top. No amount of fiddling with the controls and placement was able to solve these problems.

In spite of what the Betas did wrong, I loved what they did right, so I thought it worthwhile to apply some

AllegroMagic

The first thing I did was toss the humongous, back-breakin', not-ready-for-prime-time subs and "igniter" servo-crossover and use a pair of smaller, lightweight, low-coloration, push-pull, coupled-cavity subs crossed over at a higher frequency and slope to relieve the panels of excursion they can't handle and fill in the missing energy, an Accuphase F25 Balanced crossover and an Accuphase G18 Balanced "audio palette" to voice the subs to the room, and then set my sights and ears on improving the coherence and smoothness-of-response of the planar-magnetic, dipole panels.

Improvements include a significant reduction in coloration and listening fatigue with improved coherence and musicality. A good speaker system was now a great speaker system, able to complete with most-anything at any price, and you don't need a forklift to move it around.

AllegroFave amps for driving the Beta panels include McIntosh MC-1000 and Denon POA-8000 monoblocks, and, presumably [ I sold the Betas before I got these ], ATC SPA2-150 and RedRose M1 monoblocks. Most tube amps cannot deliver enough current to drive Beta panels; the RedRose M1's off the 2-ohm output taps be a rare exception and worth considering if you don't require maximum SPL.


AllegroSound
−  Established 1973  −
"love what you listen with"
Los Angeles, California USA
Rick@AllegroSound.com


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AllegroSound
−  Established 1973  −
"love what you listen with"
Los Angeles, California USA
Rick@AllegroSound.com
telephone 323.960.5014

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design and original content ©AllegroSound, los angeles, usa. all rights reserved.