<s>
Spectral	B-Algorithm
flux	I-Algorithm
is	O
a	O
measure	O
of	O
how	O
quickly	O
the	O
power	O
spectrum	O
of	O
a	O
signal	O
is	O
changing	O
,	O
calculated	O
by	O
comparing	O
the	O
power	O
spectrum	O
for	O
one	O
frame	O
against	O
the	O
power	O
spectrum	O
from	O
the	O
previous	O
frame	O
.	O
</s>
<s>
Calculated	O
this	O
way	O
,	O
the	O
spectral	B-Algorithm
flux	I-Algorithm
is	O
not	O
dependent	O
upon	O
overall	O
power	O
(	O
since	O
the	O
spectra	O
are	O
normalised	O
)	O
,	O
nor	O
on	O
phase	O
considerations	O
(	O
since	O
only	O
the	O
magnitudes	O
are	O
compared	O
)	O
.	O
</s>
<s>
The	O
spectral	B-Algorithm
flux	I-Algorithm
can	O
be	O
used	O
to	O
determine	O
the	O
timbre	O
of	O
an	O
audio	O
signal	O
,	O
or	O
in	O
onset	B-Application
detection	O
,	O
among	O
other	O
things	O
.	O
</s>
<s>
For	O
onset	B-Application
detection	O
,	O
increases	O
in	O
energy	O
are	O
important	O
(	O
not	O
decreases	O
)	O
,	O
so	O
some	O
algorithms	O
only	O
include	O
values	O
calculated	O
from	O
bins	O
in	O
which	O
the	O
energy	O
is	O
increasing	O
.	O
</s>
