Bass Outdoors: Difference between revisions - Bose Portable PA Knowledge

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Hi folks,

As many of you know first-hand, nearby direct sound from the L1 falls off with distance more slowly than most other speakers, including all bass speakers, and including ~~B1s~~. We rarely notice this difference indoors, because room modes in the bass impose large changes from place to place that dominate over the different rates of fall-off of the direct sound waves from the L1 and B1.

As many of you know first-hand, nearby direct sound from the {{L1}} falls off with distance more slowly than most other speakers, including all bass speakers, and including {{B1}}s. We rarely notice this difference indoors, because room modes in the bass impose large changes from place to place that dominate over the different rates of fall-off of the direct sound waves from the {{L1}} and {{B1}}.

But outdoors, there is nothing to prevent us from noticing that the bass falls off more rapidly with distance than the L1's sound does. This will happen no matter how many ~~B1s~~ we have, no matter what EQ or presets we use, and it will also happen if we use other subs, no matter how big they are. The only ways to fully prevent it would be to either give up the slow fall-off of the L1 :( or make a line array of bass speakers at least 15 feet tall (wow!), but, aside from the expense, such a thing would be extremely dangerous. :eek: So we have to find a way to optimize the effect because we can't make it go away.

But outdoors, there is nothing to prevent us from noticing that the bass falls off more rapidly with distance than the {{L1}}'s sound does. This will happen no matter how many {{B1}}s we have, no matter what EQ or presets we use, and it will also happen if we use other subs, no matter how big they are. The only ways to fully prevent it would be to either give up the slow fall-off of the L1 :( or make a line array of bass speakers at least 15 feet tall (wow!), but, aside from the expense, such a thing would be extremely dangerous. :eek: So we have to find a way to optimize the effect because we can't make it go away.

Before I explain how to do that, I want to describe the effect in a different way that makes the solution more clear. Since the bass and mid-highs are falling at different rates with distance, there can be only one distance where the balance between bass and mid-highs is "perfect". To my ears, the L1 and B1 achieve this balance point outdoors somewhere in the 10-20 foot range, call it 15 feet. But how much closer or farther must I go to hear a small change in the balance? Human hearing is not very sensitive to small changes in bass level, so 3dB counts as a small change in this frequency region. If I go to either half the distance (7.5 feet) or double the distance (30 feet) I hear a small change of 3dB in the bass balance compared to the ideal. That's because the L1 changes by 3 dB per doubling or halving of distance, while the B1 changes 6 dB, so the difference between them changes 3 dB either way. So there is a large region of distance where the bass is very close to the ideal level and that region covers about a 4 to 1 distance range, in this case about 7.5 to 30 feet.

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 Hi folks,
-As many of you know first-hand, nearby direct sound from the L1 falls off with distance more slowly than most other speakers, including all bass speakers, and including B1s. We rarely notice this difference indoors, because room modes in the bass impose large changes from place to place that dominate over the different rates of fall-off of the direct sound waves from the L1 and B1.
+As many of you know first-hand, nearby direct sound from the {{L1}} falls off with distance more slowly than most other speakers, including all bass speakers, and including {{B1}}s. We rarely notice this difference indoors, because room modes in the bass impose large changes from place to place that dominate over the different rates of fall-off of the direct sound waves from the {{L1}} and {{B1}}.
-But outdoors, there is nothing to prevent us from noticing that the bass falls off more rapidly with distance than the L1's sound does. This will happen no matter how many B1s we have, no matter what EQ or presets we use, and it will also happen if we use other subs, no matter how big they are. The only ways to fully prevent it would be to either give up the slow fall-off of the L1 :( or make a line array of bass speakers at least 15 feet tall (wow!), but, aside from the expense, such a thing would be extremely dangerous. :eek: So we have to find a way to optimize the effect because we can't make it go away.
+But outdoors, there is nothing to prevent us from noticing that the bass falls off more rapidly with distance than the {{L1}}'s sound does. This will happen no matter how many {{B1}}s we have, no matter what EQ or presets we use, and it will also happen if we use other subs, no matter how big they are. The only ways to fully prevent it would be to either give up the slow fall-off of the L1 :( or make a line array of bass speakers at least 15 feet tall (wow!), but, aside from the expense, such a thing would be extremely dangerous. :eek: So we have to find a way to optimize the effect because we can't make it go away.
 Before I explain how to do that, I want to describe the effect in a different way that makes the solution more clear. Since the bass and mid-highs are falling at different rates with distance, there can be only one distance where the balance between bass and mid-highs is "perfect". To my ears, the L1 and B1 achieve this balance point outdoors somewhere in the 10-20 foot range, call it 15 feet. But how much closer or farther must I go to hear a small change in the balance? Human hearing is not very sensitive to small changes in bass level, so 3dB counts as a small change in this frequency region. If I go to either half the distance (7.5 feet) or double the distance (30 feet) I hear a small change of 3dB in the bass balance compared to the ideal. That's because the L1 changes by 3 dB per doubling or halving of distance, while the B1 changes 6 dB, so the difference between them changes 3 dB either way. So there is a large region of distance where the bass is very close to the ideal level and that region covers about a 4 to 1 distance range, in this case about 7.5 to 30 feet.