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The following technique is Zu Denition Mk1.5 specic. It addresses the loudspeaker’s relationship with the room and works for
both 2-channel and multi-channel setups. How and where the loudspeakers excite the room and how the room reacts is relative to
the type and source of excitation and room reactance—a function of boundaries (walls, oors, etc.), boundary properties (mass,
compliance, Q, damping, texture and structure), area impedances (shape, volume), diffusion and absorption (furnishings, people,
ooring, etc.), source and type of wave excitation (loudspeaker design and placement), resonators (closets, forced air ducting,
hallways, etc.), even atmospheric pressure and humidity, though very minor, will inuence sound. While the above are beyond the
scope of this guidebook, the recommendations and listed books will start you down the proper acoustic path. Again, before you trust
another modern work relative to playback and acoustics please research the above listed references!
With your loudspeakers positioned for visual appeal, livability and delity, you can now begin ne-tuning. This involves three major
steps. In sequence they are bass, mids and treble. If you can’t ne-tune your system within an evening please contact us.
Usually, you will have one loudspeaker that is framed with less wall space, this is the loudspeaker you will ne-tune and then simply
mirror the other. Select recordings with large amounts of sustained low frequency information; dramatic pipe organ and dance
music work as do test recordings that have warbled low frequency tracks (50 - 100 Hz range). Note that steady state sine, triangle
and square wave signal prove very difcult to interpret. Bass information with some transient content will enable the listener to
make fast work of ne-tuning. With the loudspeaker playing at a moderate level, (only the “tuning loudspeaker” should be on) walk
over and kneel down next to it. Kneeling will put your head in the seated listening horizontal plane and allow you to hear how the
loudspeaker integrates with the room. Now move your head to either side of, and back and forth of the loudspeaker, say a few feet
or so (1/2 meter) in each axis. Listen to the delity of the bass, does it sound woolly and muddy right behind the loudspeaker? Is
the bass more dened a bit to the left or right? If the bass sounds better a bit to the left, move the loudspeaker to this position and
then listen again. Remember that moving the sound source also changes how the room reacts. You should only have to move the
loudspeaker a few times to get it right.
Midrange & Treble: Once the lower octaves are sounding good, natural, vibrant midrange and treble can now be dialed in.
Before you begin I think it’s important to understand a few details. Midrange tuning, while similar to that of bass, is a task of a
inches (decimeters) rather than feet (half meters) and upper octaves a mater of half inches (centimeters) and loudspeaker ring
(wavefront) axis. Even though midrange and treble changes can be heard at the “being positioned loudspeaker”, it is helpful to have
a friend position while you listen in the seating area. Here, you may want to select less bass heavy recordings; jazz, space-ambient,
violin solos, guitar solos, stuff with good overtone color and not too heavy.
Staying with the same loudspeaker “room-tuned” for low frequencies, (remember you only tune one channel and mirror its mate)
and with your favorite less heavy recording playing, start tuning for mids and highs. Move it toward the closest wall, in increments
of a few inches (4 - 6cm). While moving, the “in the listening area” observer, and possibly the person positioning the loudspeaker,
should notice midrange color (presence) transition from low and masked to open and intimate. There may be several spots within
the good sounding bass area that have good presence, go with the widest point (closest to the wall) for an expansive and engaging
stereophonic soundscape, don’t worry about center focus, Denition Mk1.5 will do quite well with its capacity for expansive and
focused image recreation. Once a midrange position is selected it’s time to work on the highest octaves. This is usually as simple as
rotating the Denition Mk1.5 loudspeaker to face directly at the seated listener. Now listen again for voice openness and intimacy,
minor placement adjustments and face angle may be necessary. If it’s a bit too treble rich, rotate each speaker to focus behind the
main listening area a few feet. Experiment. And yes, this same technique works for the Presence and Druid loudspeakers.
Additional thoughts about playback, room, and tonality
Denition Mk1.5 overcomes so many problems with regard to room, attack, sustain and decay. All the attack of the complete
audio bandwidth and musical scale emanates from the front driver array. Bass through a bit of the midrange sustain and decay are
communicated by the rear woofer array; the proper place to make room correction and tone changes that won’t mess up attack and
the soul of the sound. Why? Because the attack, more than any other aspect of a waveform, gives the listener the clues to process
source, direction, amplitude, character, intelligence, and so on. Close in importance are the dynamics within, that immediately follow
the attack. A simple example: When a piano key is struck, three main components are set in motion. These make up the attack
of a note; the mechanical noises including that of the impinging hammer, initial string motion, which has many extra components
and initial coupling of piano body and sound-board. The rst few milliseconds are very dynamic and have many features. To get the
attack correct is solely a function of the playback system and has very little to do with the room. Aside from placement, if you have
changed your system to combat your room, attack and dynamics can never be correct. Most people can only pinpoint tonal problems
with steady-state or semi steady-state music or signal, this is a big problem because room inuence on steady-state sounds are
huge, the single largest inuence if included as a component of your playback system. So, people usually tweak things to get the
steady-state and decay tonally correct which inadvertently kills the life in the attack. This is a reason why cables as tone control,
digital room correction, parametric equalizers and the like can never “x” fundamental problems, unless of course the time axis is
also programmed and correlated to harmonic structure and then set to react to any dynamic anomalies within the signal, overlaid
with the room the original recording was made in and compared... how much are real super computers going for these days?
Bun-in
All Zu loudspeakers now come with at least 160 hours of real music conditioning at what we consider to be the right levels in our
burn-in rig. This puts the loudspeakers in a position to really sound good within a few days, great in a week or two and awesome
in the end. We do not recommend recordings specically designed for loudspeaker, system or cable burn-in. The quickest and most
enjoyable way to nish the conditioning of your Denition Mk1.5 loudspeaker is to play music and movie scores that are fun, dynamic
and harmonically dense. No longer do you need to worry about cranking them up either. Let your neighbors know where they can
send tips, that’s Zu in Ogden, Utah....
Break-in Phenomenon: A running-in of driver suspension components is the prime inuencing factor in loudspeaker break-in. Cable
burn-in is also a factor but secondary. Denition loudspeakers generally go through two break-in sound transformations. The rst is
