How low should your bass go?
Here are low-frequency limits of some common musical instruments:
Four-string electric bass—40 Hz
Five-string electric bass—30 Hz
Standup (double) bass —40 Hz
Normal grand piano—27.5 Hz
Bass singer —62 Hz
Ordinary large pipe organ— 16 Hz
Kick drum (approximately)— 60 Hz
What this table doesn’t say is where the most important frequencies of these instruments are.
For a lot of bass instruments, the harmonics are louder and more important than the fundamental frequencies.
Being of higher frequency, the harmonics are more easily and quickly heard by the ear, and often contain the bulk of the melodic and rhythmic information.
What we’ve found for most popular music, the most important part of the musical range is from about 60 Hz up.
The range from 40 to 60 Hz is good for enhancing the experience, but only IF you have the 60-100 Hz range working well, and if you know how to manage the energy in your mix to avoid reverberation problems in big rooms.
Useful musical content below 40 Hz is rare in concert work. It occasionally is needed for acts that feature heavy synthesizer bass. These frequencies don’t work very well with popular music in typical large concert venues.
In their endless quest for impressive specs, loudspeaker manufacturers always seem to be building woofers that put out tons of 35 to 45 Hz at the expense of fidelity and output from 60 to 100 Hz.
Such woofers move a lot of air, but sound ugly.
The Bass Challenge
In big sound systems, it’s not easy to get good bass. Lowering woofer distortion to an acceptable level is really difficult.
There are two main reasons for this:
1. Air is very thin stuff, and bass vibrations are relatively slow. For a slow-moving bass loudspeaker cone to have much effect on the air, it has to be large and it has to travel back and forth a long way. It may seem as though a high-power woofer is a powerful, rugged, macho device, but in reality it’s a piece of paper frantically flapping in the breeze, trying to make a difference. It’s not easy to make that kind of thing linear.
By way of comparison: under water you can get loud bass down to 20 Hz from a 2-inch diameter woofer.
2. It’s surprising how low a level of distortion is actually required. There are two reasons for this: (a) the ear is 10-20 dB more sensitive to bass distortion harmonics than to the actual fundamental frequency, and (b) many people seem to like a lot of bass boost in PA systems.