Double Bass Double bass wattage equivalence

[drurb]

Well, sure-- there is no one measurement that will generalize across all basses and combinations of basses and players. I didn't mean to suggest that there was. Still, I think you'd find that the range of sound-pressure levels is quite narrow compared to the huge range that can be achieved via amplification. It would make little sense to go with extremes. After all, for any DB, the lowest levels it produces is essentially zero. IMO, it is still reasonable to ask what are, in general, the levels generated by the instrument. Invalid Link Removed a interesting Master's thesis. Interestingly, they characterize the dynamic range of instruments (including DB) as played over different musical dynamics. Take a look [Invalid or Expired Link Removed]. Try here. Then there is this classic text.

 

[robobass]

Back to the OP. Energy is energy, after all, so it's not a completely unreasonable question. I suppose you could record yourself from the pickup while monitoring the dB level in the room, then play the recording through your amp and adjust it to match the Db level when you made the recording, then figure out how many watts the amp is using. I wouldn't know how to do this, but I'm sure it could be done. It's true that if you then play the passage on a slab at the same wattage it will have a completely different character and perceived volume level.

 

[drurb]

...I suppose you could record yourself from the pickup while monitoring the dB level in the room, then play the recording through your amp and adjust it to match the Db level when you made the recording, then figure out how many watts the amp is using. I wouldn't know how to do this, but I'm sure it could be done...

Yes, it can be done but the answer may not be too helpful. One could measure the average SPL one meter from the speaker. Then, assuming a flat response, one can use the sensitivity spec. of the cabinet to determine the number of watts required to achieve that output. A interesting thing happens when the calculation is made. That is, one finds that the rms wattage required is typically quite low-- from a fraction to a handful of watts. Consider that a realistic spec for a cab is 93 dB SPL @ 1watt @1 meter. Yes, just one meter away, 1 watt gets you 93 dB SPL! So, why do we use amps rated for hundreds of watts? The answer is that we require that for musical transients. Basically, the average SPL doesn't tell nearly the full story. Musical transients can be tens of decibels above the steady-state level. So, given our example, if we assume a 20-dB increase is required, then in order to reproduce that transient, we'd need 100 watts of power (20 dB corresponds to a factor of 100 for power). Now, suppose we double the distance from the speaker from 1 meter to two meters. Assuming the inverse-square law, the level will drop by 6 dB. In order to generate the same level, we'd have to increase the amplifier power by 6 dB (a factor of four). Now we need 400 watts.