Axiom Home Page Forums General Discussion Technical Questions Help understanding decibles

Engine_Joe:

Yes, +/-3 dB is quite a notable and audible difference, because with a frequency range specified that way, there could be a 6-dB discrepancy, which could be quite audible depending on where in the audio spectrum the anomalies occur. For example, there might be a 3-dB lift at 900 Hz followed by a 3-dB dip at 1.5 kHz, so there would be 6 dB between the peak and the dip.

In measurements and listening tests correlated to the measurements, it's really crucial to try and keep the frequency response within a +/-1.5 dB window through the midrange from about 800 Hz to 4 or 5 kHz. Our hearing is particularly acute in that range, and we can easily detect larger aberrations (like 3 dB) in listening tests. After measuring and testing dozens of speakers, the models that adhered most closely to the +/-1.5 dB "window" through the mids were highly rated in the double-blind listening tests. This is simplified for the sake of clarity, but smooth, flat midrange response is crucial to speakers being judged natural and uncolored in listening tests.

Regards,

kaid,

The subjective measurements of sound intensity are fairly well established. For example, "twice as loud" normally represents a 10-dB SPL increase, which would require 10 times as much power. "Somewhat louder" is a 3 dB increase, whereas 6 dB is "significantly louder." A change of 1 dB SPL is considered the smallest change in sound pressure that's consistently detectable. And of course, the term is derived from that brilliant guy, Alexander Graham Bell (the "bel" part of "decibel"). If you want to read more on the decibel, go to the Axiom archives and click on "The Nature of Power."

Regards,

Thanks for clearing that up Alan.

Just found both of your articles in the archive. Well written! I think your explanation found in both articles has helped me understand decibels and Watts, on a more practical level.

Thanks.

It's very special, because, as you can see--the numbers all go to 11. Right across the board. Eleven, 11. . . . And most amps go up to 10? Exactly. Does that mean it's louder? Is it any louder? Well, it's one louder, isn't it? It's not 10. You see, most blokes are going to be playing at 10--you're on 10 on your guitar, where can you go from there? Where? I don't know. Nowhere! Exactly! What we do, if we need that extra push over the cliff, you know what we do? You put it up to 11. Eleven. Exactly. One louder. Why don't you just make 10 louder, and make 10 be the top number, and make that a little louder?........
"These go to 11,"
classic

i think they are looking for another drummer for their reunion tour?



bigjohn

Beat me to it! Doh!