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Expanded version of the original paper presented at
the 48th Audio Engineering Society Convention California, USA
17—198
Loudspeaker phase measurements,
transient response and audible quality
By Henning Moiler, BrueJ & Kjaer
Abstract
The transient response of ­
plex loudspeaker system can often
be improved simply by repositioning
the speakers. How much axial move­
ment is required will be indicated
by studying the phase response of
the system.
The phase response O(s) together
with the amplitude response A(s)
gives plete transfer function
H(s) = A(s) eJ^fs) which describes
the steady state and transient re­
2971 6202
sponses of the system.
This note will show that with the making loudspeaker phase response drums, or bass drums pizzicato from
Phase Meter 2971 and Phase De­ measurements. — Techniques us- strings, short blasts from horns, at-
lay Unit 6202, a new technique ing tone bursts or fast Fourier Trans- tack on piano and guitar and the
has been introduced to make swept form have until now provided the clash of snare drums, cymbals and
phase measurements as easy as only possibilities. triangles.
swept amplitude measurements.
It is known from Fourier analysis This Application Note will concen-
It will be shown later that loud­ that a transient can be seen as a trate primarily on phase response in
speakers are not necessarily mini­ combination of an infinite number relation to transient response, but
mum phase systems and therefore of sine waves. A swept phase meas- will also consider subjects such as
that the phase response can not be urement of the response of a loud- minimum and nonminimum phase
calculated from the amplitude re­ speaker system to a transient will in- behaviour and ph