User Manual
Multichannel Monitoring Tutorial Booklet (M2TB) rev. 3.5.2
Masataka Nakahara : SONA Corporation
©2005 YAMAHA Corporation, ©2005 SONA Corporation
51 / 74
[Fig. 36] Playback characteristics using Bass management controller (1)
A bass management controller is a crossover filter that routes the low-frequency component to a sub-
woofer. This means that the sub-woofer will output the low-frequency components combined from each
of the main channels as well as the LFE signal, making it impossible to adjust the gain of only the LFE
channel after bass management (the sub-woofer amp) occurs. Thus, the bass management controller must
also provide functionality for switching the gain of the LFE playback sound (+10 dB: DVD-Video and
movies etc., +/-0 dB: DVD-Audio and Super Audio CD etc.)
The bass management controller includes not only the simple function of supplementing the low-
frequency response of the main speakers, but also improves the low-frequency playback response and
allows checking of how the material will play back on consumer equipment.
Major advantages of a bass management controller are listed below.
A. The low-frequency response of the main channels (L, C, R, LS, RS) can be made consistent.
By ensuring that the low-frequency response (which is most prone to inconsistency) is consistent, the bass
management makes it easier to ensure that all channels have the same response.
Regardless of whether the response is good or poor, consistency of response between all channels is the
most important point for a professional monitoring environment, whether it be two-channel or multi-
channel. In the case of two-channel monitoring, it is fairly easy to make the response of all channels (L
and R) identical by making the listening environment symmetrical between left and right. However in the
case of multi-channel monitoring, simply making the listening environment symmetrical between left and
right is not usually enough to ensure consistency, in particular for low-frequency response.
B. By placing the sub-woofer in the optimal location, the low-frequency response of all channels can
be improved.
In small- to medium-sized rooms, there is a very limited range of speaker locations that produce good
low-frequency response.
Since there is a high degree of freedom in placing the sub-woofer can be positioned in the location to
optimize the frequency response of all channels for that room.
C. The +10 dB band gain for the LFE channel can be ensured.
By using bass management, a playback gain of +10 dB relative to the main channels can be applied to the
entire LFE bandwidth.
If the +10 dB playback gain is not consistently applied to the LFE, the LFE effect will often be obscured
by other channels and will not be heard correctly (film, DVD-Video). An environment in which the
playback quality of the LFE channel is ensured is extremely important for LFE production for film or
DVD-Video.
-20
-10
0
+10
+20
20
31.5
50
125
200
315
500
800
1.25k
2k
3.15k
5k
8k
12.5k
20k
1/3 octave band center frequency [Hz]
Relative SPL [dB]
+10dB
LFE
L, C, R, LS, RS, BS
80Hz
SUBWOOFER
MAIN SPEAKER