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Pioneer S-4EX Speaker System: Sound Coherency Makes the Difference

Sound Coherency Makes the Difference

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Pioneer S-4EX Speaker System: Sound Coherency Makes the Difference

Pioneer S-4EX Speaker

Anyone familiar with the Pioneer TAD Reference One loudspeaker knows that they can expect an extraordinary listening experience. The TAD Reference One has received rave reviews from many audio critics, primarily for their accuracy, definition and stunning realism. One reason is Pioneer's Coherent Sound Technology (CST), comprised of a concentric beryllium midrange and tweeter. However, the TAD Reference One speakers are priced at $60,000 per pair, way out of reach for most music lovers.

Pioneer EX Series and the TAD Story

Enter the Pioneer EX Series, a speaker line designed to deliver the TAD experience to the masses. Well, maybe not the masses, but closer to fiscal sanity than the TAD Reference One speakers.

The Pioneer S-4EX speakers are an off-shoot of the TAD line, designed with many of the same features to retain the sonic signature of the TADs. TAD (Technical Audio Devices), part of Pioneer's pro-audio division was launched when Andrew, Director of Speaker Engineering at Pioneer Electronics USA, Inc., joined the company over a decade ago. His mission was to build upon the expertise Pioneer had developed years earlier in beryllium midranges and tweeters. Mr. Jones is a legendary speaker craftsman who probably knows more about speakers than anyone I've met. His expertise becomes very clear when you listen to the S-4EX speakers.

Beryllium Concentric Drivers

Pioneer S-4EX Speaker


Beryllium is a rare earth metal that has desirable characteristics when used in speakers, mainly a very high stiffness to weight ratio. High stiffness means they don't flex or bend when reproducing music, and low weight gives them the ability to respond quickly to an audio transient – both desirable characteristics.

Long story short, Pioneer introduced the TAD Reference One, a reference loudspeaker heralded as one of the finest, albeit at $60,000 per pair! The Reference One incorporates a concentric midrange/tweeter with beryllium drivers. Concentric drivers are phase aligned, meaning that the polar patterns of the midrange and tweeter arrive at the ear simultaneously, giving them a unique sound quality known as sound coherence. In my opinion, sound coherency is one of the most important and often overlooked aspects of music reproduction. It results in unusual transparency, openness and detail that is instantly recognizable - you know sound coherency when you hear it.

Features of the Pioneer S-4EX Speakers

The Pioneer S-4EX is a three-way speaker with a 6.5" bass/mid-bass driver, and a concentric magnesium midrange and ceramic graphite tweeter. Magnesium and ceramic graphite are used due to the high cost and technical difficulties of working with Beryllium but retain similar performance characteristics.

The S-4EX speakers are too short to be called floorstanding speakers and too tall to be considered bookshelf speakers. They perform best when placed on high quality speaker stands at ear height when listening. And they produce extraordinary sonic results. Anyone who appreciates accurate music reproduction should hear them.

A speaker enclosure should be as stiff and rigid as possible. A knuckle rap on the enclosure should sound solid as if you're knocking on concrete. Although the Pioneer S-4EX speakers are constructed with wood and covered with a fine Dark Teak veneer, they sound as solid as if they're made of concrete.

The Results of Sound Coherency

From excellent bass extension to transparent midrange and exquisitely detailed high frequencies, the S-4EX speakers are easy to describe and easier to enjoy. I could list all of the many music tracks I listened to and describe my experiences, but I'll focus on a few of my favorite and most significant.

The best example of coherency came from Don McClean's 'Vincent' from his American Pie album (Curb Records). His guitar had extraordinary articulation with quick attack and outstanding transient response, precisely like a percussion instrument should sound. The benefits of the speaker's frequency response, which extends to 100 kHz became clearly evident. When combined with the vocals and other instruments, the soundstage sounded spacious with good center imaging. This disc is recorded well, but is certainly not an audiophile recording. 'Castles in the Air' from the same disc sounded detailed and accurate.

Sara K's recording of 'What's a Little More Rain' (Chesky Records), certainly an audiophile recording, sounded very open and the speakers resolved many subtle sonic details that I've not heard before.

The bass track on 'Bird on a Wire' from Jennifer Warnes' Famous Blue Raincoat album (Shout Factory) sounded exceptional with deep extension and precise definition without the need for a subwoofer. Mid-bass was snappy and tight in 'Sad Old Red' from Simply Red's Picture Book album (Elektra Records).

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