Phil Jones Bass M-500, Руководство пользователя, Страница: 14 / 25

13
dimensions heavily influence them when the walls reflect the sound waves, causing them
to collide by adding together or canceling each other out. This causes some fundamental
notes (the ones you feel more than hear) to ring out louder than others and some note not
to be heard at all.
Here is an indication of where fundamental bass frequencies are, showing open string’s
approximate frequencies and acoustic wavelength.
F# string 24Hz 46 feet
B string 31Hz 36 feet
E string 41Hz 27 feet
A string 55Hz 20 feet
D string 73Hz 15 feet
G string 98Hz 11 feet
C string 130Hz 9 feet
This may give you some indication of the offending notes (frequencies) that may be
booming or resonating louder or quieter than others. For example if your speakers are 5
feet from a wall, the open A string may sound lack of weight. That could be because the
path length of the reflected sound off the wall from your speaker is exactly corresponding
to half a wavelength on the open A string causing at that particular note a cancellation.
Note that the position of where you place your speakers will ultimately affect your tone.
Placing a speaker with the back close to a wall will help to reinforce the lower notes.
Placing the speaker in a room corner will further enhance the low notes.
Unfortunately for bass players, low frequencies are always very difficult to control with
room acoustics. The reproduced wavelengths of the notes you are playing often
correspond to the room dimensions, in which case the reflected sound off the walls
interferes with the sound from the speaker. So the graphic EQ is by far your best weapon
of choice in killing standing waves that develop in the room. From about 250Hz upwards,
the graphic EQ is just controlling your overtones on the strings bearing in mind that even
the 60Hz control will alter the second harmonic on an open B string.
The amount of control per frequency band is up to 36dB (+/- 18dB). You should try to
avoid using excessive boosting of EQ on the lower frequency ranges (30,40,60 and
100Hz bands) as this will reduce amplifier headroom and possibly damage your speakers,
since the amplifier may force them to move beyond their physical capability. If you hear
large amounts of distortion coming from your speakers when you boost the lower bands,
you should immediately back off on the EQ. If you cannot get enough low-end weight for
your taste, maybe you need more speakers.
If you are playing a 4 string bass, the lowest fundamental note is 41.2Hz on the open E
string. It is therefore not necessary to boost the first 30Hz band on the EQ because it is
set lower than the lowest note you play and it is out of range on your instrument. In fact
reducing this band will considerably tighten up you bottom end and make your bass
sound more punchy.