El: I agree that we need to have some type of "guidelines" regarding SPL's on this forum for general reference.
As mentioned above, you really have to measure spl's at the seated listening position with "C" weighting. Measuring SPL's in any other manner leaves too much for interpretation and differences in installations. Since not all speakers project sound in the same manner, you and i could both measure 95 dB's at 1 meter but have different SPL's at an identical yet greater distance. As such, we would have skewed perceptions of what was going on unless we compared levels as we heard them when seated. After all, 95 dB's at my seat would be equivalent to 95 dB's at your seat, regardless of the differences in the room, speaker radiation patterns or distance from those speakers.
On top of that, these readings should only be taken with the mains and any subs used when operating in two channel mode. Running a center and surrounds that contribute to the overall SPL level will only confuse those of us trying to work off of a given set of standards. If one wants to include readings taken in multi-channel mode, that is fine. Just for sake of clarity though, those readings should be identified as such. Otherwise, since this is primarily a two channel forum, we should be able to assume any readings taken were in two channel mode.
I think that something like this would take these forums a step further in the ability to communicate various ideas with less guess-work involved. After all, when Fred thinks "loud" is 95 dB's at his seat and Barney thinks that 110 dB's is "loud" at his seat, it is hard for them to communicate and understand exactly where the other guy is coming from. If I can say that i'm listening at XX dB's at my seat, you can easily duplicate that ( within a reasonable window of tolerance ) and know exactly where i'm coming from.
If we did this, i think that we would find that most people don't listen near as loud as they think they do on an average basis. While momentary peaks might climb up somewhat, average SPL's are what should be measured and compared. After all, someone using a recording with 5 dB's of dynamic range ( highly compressed rock music ) will have a FAR higher average SPL than someone using a classical recording that has 50 dB's of dynamic range. Comparing SPL's as taken on the peaks between these two installation would be quite useless. The system playing rock music might be averaging 105 dB's and peaking at 110 while the classical recording is averaging 70 dB's and peaking at 110. Both are peaking at the same SPL, but believe me, one of them is WAY louder than the other. Sean
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PS... Most speakers hit a brick wall at a specific point and go into dynamic compression at or slightly above that point. After that point has been reached, they are very non-linear in output and their distortion characteristics take off like crazy.
As mentioned above, you really have to measure spl's at the seated listening position with "C" weighting. Measuring SPL's in any other manner leaves too much for interpretation and differences in installations. Since not all speakers project sound in the same manner, you and i could both measure 95 dB's at 1 meter but have different SPL's at an identical yet greater distance. As such, we would have skewed perceptions of what was going on unless we compared levels as we heard them when seated. After all, 95 dB's at my seat would be equivalent to 95 dB's at your seat, regardless of the differences in the room, speaker radiation patterns or distance from those speakers.
On top of that, these readings should only be taken with the mains and any subs used when operating in two channel mode. Running a center and surrounds that contribute to the overall SPL level will only confuse those of us trying to work off of a given set of standards. If one wants to include readings taken in multi-channel mode, that is fine. Just for sake of clarity though, those readings should be identified as such. Otherwise, since this is primarily a two channel forum, we should be able to assume any readings taken were in two channel mode.
I think that something like this would take these forums a step further in the ability to communicate various ideas with less guess-work involved. After all, when Fred thinks "loud" is 95 dB's at his seat and Barney thinks that 110 dB's is "loud" at his seat, it is hard for them to communicate and understand exactly where the other guy is coming from. If I can say that i'm listening at XX dB's at my seat, you can easily duplicate that ( within a reasonable window of tolerance ) and know exactly where i'm coming from.
If we did this, i think that we would find that most people don't listen near as loud as they think they do on an average basis. While momentary peaks might climb up somewhat, average SPL's are what should be measured and compared. After all, someone using a recording with 5 dB's of dynamic range ( highly compressed rock music ) will have a FAR higher average SPL than someone using a classical recording that has 50 dB's of dynamic range. Comparing SPL's as taken on the peaks between these two installation would be quite useless. The system playing rock music might be averaging 105 dB's and peaking at 110 while the classical recording is averaging 70 dB's and peaking at 110. Both are peaking at the same SPL, but believe me, one of them is WAY louder than the other. Sean
>
PS... Most speakers hit a brick wall at a specific point and go into dynamic compression at or slightly above that point. After that point has been reached, they are very non-linear in output and their distortion characteristics take off like crazy.