SOUND QUALITY
The Summit Xs are big, yet at the same time they fitted my lounge easily, either side of a large Victorian fireplace. This is a fairly typical set-up and the speakers slotted in nicely – a big plus point as high quality electrostatics go, because traditionally they don’t fit into my home easily, nor any home where space is limited.
    Driven by Quad Elite QMP monoblock power amplifiers fed by an Astell&Kern AK120 high-resolution digital player, the most immediate and impressive aspect of the Summits was their vast sound stage. In my room the cabinets were 7ft apart, and since each is 5ft high when seated, I was listening upward to a celestial image in front of me, of a size few loudspeakers can manage. Because the entire XStat panel radiates coherently the full area is alive and Diana Krall had a looming presence at the end of the room, singing 'Narrow Daylight' (24/96). This is largely down to the panel being an acoustic line source, not a point source; the XStat panel is different from most loudspeakers in this respect.
    The panels image more emphatically than conventional drive units, giving singers a visceral presence, with supporting instruments laser-etched in their location. I decided to raise the rear of the cabinets a little, using the adjustable feet, to get full treble extension, because this directed more treble energy at me, making the Summit Xs exceptionally analytical – as reviewers like it!
    In practice I have found the Electromotion panel allows me to clearly identify the image imprecision jitter in digital sources causes and the Summit X panel is even more overwhelmingly ‘obvious’ in its presentation when set to fire down like this. To be technical about it, the large XStat panel radiates more high frequency acoustic power than other loudspeakers and that makes treble very obvious, although the Summit X can’t be described as “bright”.It is brutally analytical though and, as I found with the Montis, this means you have to be understanding about what your source and signal chain is doing.

When I played old CDs like Gerry Rafferty’s ‘North & South’ album (1988), ripped to the AK120, treble frequently sounded hard, but this is old digital for you; both LP from my Garrard 401, SME312S arm and Ortofon Cadenza Bronze cartridge set-up, and high-resolution recordings from the AK120 were fine. CD was best heard via the Audiolab M-DAC using its optimised time domain filters.
    Martha Gomez hung in space between the big panels, singing 'Lucia' (24/96), plucked guitar strings sounding sweetly resonant, whilst accordion had size and presence to one side of the sound stage.The line source nature of the tall panels gave images life-like dimensions and this contributed strongly to the overall impact of the Summit X’s sound staging.
    Martin Logan’s XStat electrostatic panels are about the best in the business – delivering an airily clear sound, completely free of colour, in a way that only electrostatic loudspeakers can do.With no box coloration, and no phase anomalies, the Summit Xs tells it like it is – and other loudspeakers struggle to get close.
    

In describing basic presentation, however, I will mention that the Summit X does not have the chesty lower midrange warmth of big box loudspeakers – and some listeners don’t appreciate this. Which brings me to the bass cabinet.
    Running the two bass units progressively out-of-phase to mimic dipole dispersion at crossover reduced energy in the crossover region and this can be seen as a shallow dip in upper bass in our measurements. In use this does make integration smoother and more harmonious between bass monopole and panel dipole; I was less aware of there being two separate entities – bass and all else – with the Summit X than with other Martin Logan hybrids.
    With twin, independently-powered 10in bass units the Summit X goes low in obvious fashion. Playing the Eagles ‘Somebody’, from their CD ‘Long Road Out of Eden’, I have rarely heard so much subsonic power from the kick drum but at the same time it sounded well-defined and lacked any sign of being overblown.
    I tried various bass settings and ended up, not unexpectedly, with -2dB bass cut at 50Hz to de-emphasise room modes and the 25Hz control at flat, because my 17ft room is starting to attenuate bass this low.
     Jackie Leven’s ‘Clay Jug’ (LP) best demonstrated the low-end kick of the Summit X, bass drum having a delicious power and presence, whilst the bass guitar strode along authoritatively. With Jackie talking and singing down at me I was more than impressed by the Summit X and its sense of firm bass control.
    Not only did the bass on rock tracks sound deep and powerful but orchestral kettle drums had scale and presence too: on Rimsky Korsakov’s 'Snow Maiden, Dance of the Tumblers' (24/96), a massive kettle drum strike shook my room firmly. The bass units of the Summit X not only produce prodigious subsonic power, they also manage to sound tight and clean at the same time.
    Marianne Thorsen playing violin with the Trondheim Soloists (24/96) showed how the big XStat panel brings a sense of firm body and clear outline to string instruments, due to its consistent phase behaviour. The sense of detail and insight provided was enormous, partly because upper midrange output is so strong and consistent. However this does make the Summit X a revealing listen rather than warm and cuddly. But although some of my older and well worn LPs sizzled conspicuously as the Ortofon Cadenza Bronze tracked the lead-in groove, I also realised I was playing very loud most of the time and this noise was soon submerged by the music.