Tuesday, September 22, 2020

Linaeum Tweeters: Exotic Tweeter For The Masses?

Often described as the lowest cost alternative for budget conscious audiophiles disenfranchised with the dome-tweeter sound, is the Linaeum Tweeter a true-blue “exotic tweeter” for the masses?

By: Ringo Bones

When RadioShack collaborated with Mystical Audio Limited to release their Optimus PRO series of hi-fi loudspeakers back in the mid-1990s, it was hailed by audio experts and reviewers as the “best sounding loudspeakers they have ever heard in the $300 to $500 price range”. While actual audiophiles who can’t afford ribbon-tweeter and planar-magnetic tweeter equipped exotica in the four-figure to five-figure price range had hailed the RadioShack Optimus PRO series as a veritable godsend at the time. I mean hearing what an actual 1990s era grunge guitar band produced in a budget-conscious audiophile’s listening room after concluding budget dome-tweeters seem to just don’t cut it sonic wise can be a revelation back then.

Sadly, the bass and lower midrange sound quality of the RadioShack Optimus PRO series was sonically below par in a side-by-side comparison to their old-fashioned dome-tweeter equipped competition in the $250 to $1,000 price-range. Not to mention that the inherent nature of the Linaeum Tweeter design will produce a harsh high frequency sound quality if operated below 3,000-Hz in the audio spectrum. But what makes the Linaeum Tweeter a value-for-money alternative to the good old-fashioned dome-tweeter in the entry-level hi-fi loudspeaker market?

What’s so special about the Linaeum Tweeter? In a conventional tweeter, a coil of wire is suspended between the circular poles of a ring-shaped magnet that moves a cone or a dome-shaped diaphragm backwards and forwards according to the dictates of the electrical signal, allowing it to produce audible sound from the power amplifier’s electrical signal. In the Linaeum Tweeter, there is still a voice coil, but this time it is flattened into a vertical shape and suspended between opposed rectangular magnetic poles. The voice coil still moves backwards and forwards, but instead of driving a cone or dome-shaped diaphragm, it pushes and pulls the vertical joining point of two semi-cylindrical 3-inch long sheets of stiff plastic film, each of which is fixed at its own end. Imagine two empty beer cans side-by-side, the point where they touch is where the voice coil is attached. Under the influence of the electrical signal from the power amplifier, the two semi-cylinders rotate back and forth, the resultant traveling waves producing sound.

The advantages of the Linaeum Tweeter design over a conventional cone and dome-shaped tweeter design are a uniformly wide horizontal dispersion pattern of the produced sound and good linearity, both of which lend the Linaeum Tweeter some of the attributes of a good, but far more expensive, planar drive unit. If as in the RadioShack Optimus PRO LX series, two sets of diaphragms are placed back-to-back with a common magnet structure, sharing a common voice coil, those at the rear pull when the front one’s push. The resulting sound radiation to the rear should  produce an enhanced feeling of “airiness” to the loudspeaker’s sound in all but the most “acoustically dead” –I .e. unreflective – of listening rooms.

The Linaeum Tweeter further gained its reputation as the “exotic tweeter for the masses” after RadioShack decides to discontinue the Optimus PRO LX series and sold them heavily discounted – including the after-market replacement Linaeum tweeters – around after 9/11. Some RadioShack outlets had even sold the Linaeum Tweeter as low as $15 per pair further on. Now virtually impossible to find outside of heavily inflated priced working ones offered on e-bay, adventurous hi-fi enthusiasts had managed to experiment with them during the first two decades of the 21st Century. If operated above 3,000-Hz, Linaeum Tweeters offer more natural and realistic sounding high frequencies that dome tweeters in the $100 to $500 price range. When operated at 6,000-Hz or higher as a super-tweeter, the Linaeum Tweeter can easily make a DIY loudspeaker sound as if it is 10 to 20 times the price of its actual purchase price.

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