Fyne Audio SUPERTRAX - Page 6

6
HARMONICS, PHASE & THE IsoFlare™
POINT SOURCE
Fyne Audio’s IsoFlare driver is a point
source system whereby the bass /
midrange driver shares a common time
aligned centre with the high frequency
unit. Providing outstanding stereo
imaging, even off axis, energy is radiated
isotropically with constant directivity,
followingtheareofthedrivercone.
Sound is produced as if emanating from
a single point in space.
Over the frequency range that the
IsoFlare operates, it does a far better
job of preserving the harmonic
content of instruments compared
with a conventional discrete drive
unit arrangement. This is because
the low and high frequency sounds
are generated from the same point
in space (point source), and there
are no time and phase differences
between harmonics below and above
the crossover point, as with discrete
speakers.
Also, the relationship in amplitude
of fundamental and harmonics is
accurately preserved both on axis and
at points off axis. In a normal room, the
majority of sounds perceived by the
humaneararereectionsgeneratedby
the off axis response of the speaker. The
even off axis response of the IsoFlare
meansthatthereectedenergyhasthe
same harmonic structure as the direct
on axis energy.
The other element of the IsoFlare that
is a function of its point source nature,
is it provides linear phase response.
Every loudspeaker or audio device
exhibitsalowpasslterfunctionand
consequently acts as a frequency
independent time delay in the pass
band, otherwise known as a linear
phase response. However, with discrete
drive units that are not time aligned,
severe phase errors occur in the pass
band, while the IsoFlare offers an
almost ideal linear phase response.
This better preserves the harmonic
relationship of instruments and
improves the transient performance.
Note though that the phase response
does deviate from the ideal at very
high and very low frequencies. This is
a natural result of the high and low
frequency roll off points of the system.
To reduce the low frequency phase
error, we would add a subwoofer, which
does more than just add bass. It is this
reduction of phase error that is one of
themainbenetsofawellintegrated
subwoofer. Music with no apparent bass
content will sound more natural when
this error is removed.
Likewise, the addition of a super
tweeter, time aligned to the acoustic
centre of the IsoFlare, will reduce the
high frequency phase error by moving
the low pass roll off point much higher.
So even if we ignore for now the
perception of sound above 20kHz, the
addition of a super tweeter will better
preserve the harmonic relationship
between instruments and is apparent
down to low frequencies. This is a very