Much of the energy used to drive the Sound Lab is soaked up by the passive crossover, because SL (for other compelling reasons) chose to use a resistance in the RC network that comprises the high pass filter that is much lower than the natural impedance of the panel itself, sans RC network. Thus the amplifier is expending more energy to drive the resistor than to drive the panel. With RC network removed, the big SLs are remarkably efficient and present an impedance in the 20 to 25 ohm range (never below 20 ohms) from about 100Hz to 5kHz. Impedance goes up below 100Hz and down between 5kHz and 20kHz. This gets rid of the midrange impedance issue that Ralph alludes to. And of course it’s favorable for an OTL tube amp. I daresay that a 50W amplifier is sufficient; my Atma-sphere amps with about 100W are coasting. Of course, you also have to replace the treble audio trans with a suitable full range audio trans. They’re not easy to find.
System that sounds so real it is easy to mistaken it is not live
My current stereo system consists of Oracle turntable with SME IV tonearm, Dynavector XV cartridge feeding Manley Steelhead and two Snappers monoblocks running 15" Tannoy Super Gold Monitors. Half of vinyl records are 45 RMP and were purchased new from Blue Note, AP, MoFI, IMPEX and some others. While some records play better than others none of them make my system sound as good as a live band I happened to see yesterday right on a street. The musicians played at the front of outdoor restaurant. There was a bass guitar, a drummer, a keyboard and a singer. The electric bass guitar was connected to some portable floor speaker and drums were not amplified. The sound of this live music, the sharpness and punch of it, the sound of real drums, the cymbals, the deepness, thunder-like sound of bass guitar coming from probably $500 dollars speaker was simply mind blowing. There is a lot of audiophile gear out there. Some sound better than others. Have you ever listened to a stereo system that produced a sound that would make you believe it was a real live music or live band performance at front of you?
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Many years ago as an audio dealer peddling "descent stuff" , I attended a concert featuring the Polish national champion string quartet -- to "recalibrate" my ears. It didn't take long to come to the realization that our equipment was embarrassing insufficient at replicating the experience of a live performance. The lack of lower midrange detail struck me as the most prominent deficiency. As a result we upped the ante on just about everything in the musical chain and lived happily every after. Well, for 2 more decades, anyway. |
@dekay Sorry. Slip of the typing finger. 1971, Bristol VA/TENN King College (now "University") concert. We played a set, they played a set. Will promise to proofread my posts from now on!! Cheers! |
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