RMAF12: Sjöfn Hifi and catching ( the clue )

I was charmed by ( the clue ) when Lars Erickson helped to arrange their visit here at Chez Moi this year. For $999, they’re marvelous — not only in their sound, but in the way they use the space you have. Especially if you don’t have any. Still very highly recommended!

I found the Sjöfn Hifi crew having a fine time on my visit through the room at RMAF — here driven by Hegel gear and wired up with Supra cables. The novel bit? Stacking!

Lars took two sets of ( the clue ) and with the help of a short spacer, inverted a pair and stacked it right on top of the another. Why? Well, the setup, with the top speakers wired off the binding posts of the bottom one, Lars said this made them 6dB more sensitive and whole system sound dramatically more dynamic. A bit precarious, perhaps, but hilariously effective — this room was hopping.

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About Scot Hull 1039 Articles
Scot started all this back in 2009. He is currently the Publisher here at PTA, the Publisher at The Occasional Magazine, and the Executive Producer at The Occasional Podcast. There are way too many words about him over on the Contributors page.


  1. Hi,

    My name is Jim Croft. I developed ( the clue ), and the deuce clue alignment, for Lars at Sjöfn HiFi.

    It has been great to read of your experience of the clue in your previous reviews and your show report.

    Regarding the mention of double Advents (we all tried them back in the day) and the question about the deuce spacing distance — Normally, when stacking loudspeakers, one most often ends up with more ‘quantity’ of sound, but a sacrifice in ‘quality’ of sound. With careful set-up the deuce clue not only provides a significant increase in undistorted dynamic range, it also provides a new room-interface profile that further advances the ‘quality’ of sound.

    With the clue, the unusual design parameters are such that they lend themselves to maintaining their original, novel phase/amplitude alignment when arranged in a symmetrical vertical array as Lars demonstrated with the deuce clue at RMAF.

    The deuce configuration requires the same care in set-up criteria as a single pair does. The starting point is the same as the standard set-up, with the specific height, listening distance to width ratio, angles and boundary coupling of the first, lower set of the clue.

    Once that is complete, then one applies the second, inverted clue above the first one. It is critical that the second clue is not merely stacked on top of the lower unit.

    When the listener is seated, the downward facing surface of the second device (normally the top) should be substantially the same distance above the ear as the top surface of the lower clue is below the ear. It is also important to have the space between the upper and lower systems to remain relatively open, so as not to alter the diffraction characteristic or create a shift in baffle gain near the tweeter.

    When the system is calibrated to the room and listening position in this manner it will maintain a coherent wavefront across a broad width of listener positions.

    The quality improvement comes from the fact that the off-axis room interactions (particularly the critical, coloration producing, vertical floor/ceiling reflections) are now diversified to further reduce room induced midrange colorations from secondary arrivals, and to create a diversity relationship with the room at low frequencies, smoothing standing wave modes and increasing gain at modal null frequencies.

    This ‘coherent-on-axis’ // ‘diversity-off-axis’ array-source, adds further improvement much of the original design criteria for the clue while providing at least 6-dB of increased large signal capability.

    In terms of the question about impedance; the clue is designed with a carefully matched unit to unit impedance curve and input buffer that maintains consistent sound quality whether wired in parallel or series, allowing an impedance match to one’s amplifier when powering the 4 speaker array.

    Lars and I will be providing new set-up instructions that will offer a more comprehensive statement of the way to maximize the capability of the deuce array.

    I apologize if this was wordier that what you and your readers were looking for, but hopefully it provides at least a partial answer to the question asked.

    If there is any other information I can provide, or questions I can answer about the clue or the deuce clue, please let me know.

    All the best,

    Jim Croft – Croft Acoustical // Sjöfn HiFi


  2. Cool – stacked Clues! Do you know if he arbitrarily picked the spacing distance, or was this calculated to offer the best integration between the two speakers and the room?
    Cheers! Vinnie

    • Great question — dunno. It felt planned, but I’d need to ping Lars.

    • When I stacked my Large Advents, they were on top of each other with no space in between. The doubled setup was better than a single set, and my KLH integrated didn’t mind the load.

      • If I’m not mistaken, the sensitivity should go up as the impedance goes down, right? Lars said 6dB of gain, which seems pretty standard, but I’m betting the nominal impedance drops by half. Assuming the speakers are reasonably friendly load (6+ ohms), halving it shouldn’t be too much of an issue for most amps.

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