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cam
07-16-2004, 06:04 PM
but I have forgot how many db of sound do you lose per foot from the speaker. I'm just trying to calculate roughly how many watts my receiver is having to push my speakers to achieve a certain level. Thanks.

This Guy
07-16-2004, 06:56 PM
Point Sources will lose 6dB's per doubling of distance while line arrays, big ribbons, or electrostats will lose only 3 dB per doubling of distance.

cam
07-16-2004, 07:19 PM
Point Sources will lose 6dB's per doubling of distance while line arrays, big ribbons, or electrostats will lose only 3 dB per doubling of distance.
Those are big losses. So if my speakers are 93db 1 watt 1 meter, then that same 1 watt at 2 meters is 87db and 4 meters would be 81 db.

This Guy
07-16-2004, 08:02 PM
Yep, that's why receivers and amplifiers are getting so big nowadays.

cam
07-17-2004, 08:05 AM
Ok one more question, with my senerio 1 watt 4 meters 81 db. What happens to the overall db level when you have a second speaker or 3,4, or 5 speakers all pushing 1 watt at 4 meters 81 db. Im just guessing hear but I will say that 1 watt per speaker will give me an overall db level of 93 db. I just added 3 db for every speaker getting 1 watt. Am I correct.

This Guy
07-17-2004, 09:04 AM
One watt per speaker will be 99 dB. You add 3 dB because you double the power by adding a second speaker, and another 3 dB for the doubling of surface area. The 93 dB rating is for 1 speaker with 1 watt.

cam
07-17-2004, 09:49 AM
One watt per speaker will be 99 dB. You add 3 dB because you double the power by adding a second speaker, and another 3 dB for the doubling of surface area. The 93 dB rating is for 1 speaker with 1 watt.
Thanks This Guy. So with 5 speakers (all 93db 1 watt 1 meter) I could achieve 99db with 1 watt going to each speaker at 4 meters(12 feet). Taking it one step further I could acieve 102db with 2 watts, 105db with 4 watts, 108 with 8 watts and so on. Is this then correct.

This Guy
07-17-2004, 10:23 AM
Sorry I misread your post. It would be 99 dB for two speakers with 1 watt from 1 meter. So from 4 meters away two speakers with 1 watt would be 87 dB at your listening position. With four identical speakers, with the 1 watt of power, and the same distance away from you, it'd be 93 dB at your listening position. The fifth speaker really wouldn't make a difference in volume. So with 2 watts to four speakers you'd get 96, 4 watts 99, 8 watts 102, 16 watts 105, etc... Someone correct me if I screwed something up cause this stuff can get confusinig.