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How loud is 90 db at 1 meter on a Tweeter?

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  • How loud is 90 db at 1 meter on a Tweeter?

    I can understand the ratings of a midrange rated at 90 db, but do we really play our tweeters at 90 db when they are playing music. I'm not talking about screaming rock, I'm talking about orchestral, or chamber, or a small folk group. I'm wondering if the rating for tweeters is unrealistic for everyday listening---not trying to reproduce a rock concert in your living room.

    I understand what the ratings mean, I just don't understand how, at least for a tweeter, this related to real life listening in a living room.

  • #2
    If you're talking about the sensitivity rating, it simply helps you to match the tweeter level to the midrange, to get flat frequency response. Of course you don't necessarily run any of the drivers at 90dB SPL.
    Francis

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    • #3
      Originally posted by fpitas View Post
      If you're talking about the sensitivity rating, it simply helps you to match the tweeter level to the midrange, to get flat frequency response. Of course you don't necessarily run any of the drivers at 90dB SPL.
      I understand this. But it might also be an inaccurate measurement, since we don't usually run drivers at this level. And, since at different volume levels the intermodulation distortion of the cone or ribbon increases with power place on it, maybe it would be better to have a measurement at 60 db, 80 db, and 92 db. Also the number never indicates whether it is takes at specific frequencies(and what they are) or whether its taken at a sweep. And of course its never taken with music, since that would give a totally innacurate measure, except that we don't listen to tones, we listen to music, usually.

      It might account for the reasons why some people comment that a particular speaker is wonderful and others comment that its horrible, but never does anyone qualify what kind of sound they listen to and at what levels. Recently I had someone tell me that my line arrays would sound a lot better if I added a line of 8 mid woofers to the one I already had. And then, I told him that I listen mostly to classical, blues and folk. And he said he listens to car chases and gun shots.

      To top it all off, if we run the driver in a line array with ten of them, then we might expect that a better measure would be 30 db down....maybe.

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      • #4
        It's an attempt to set a usable industry standard that can be scaled up or down accordingly.
        Inverse square Law is one variable.
        "Not a Speaker Designer - Not even on the Internet"
        "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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        • #5
          You don't need to run the tweeter at that level to measure sensitivity, it can be measured at a lower level and the output at 1W input extrapolated. Still, the majority of modern tweeters won't run into significant power compression until well over 90dB SPL. The sensitivity is only a guideline anyway, a competent designer will measure the finished speaker FR and tweak driver levels as needed.
          Francis

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          • #6
            The measurement is by no means inaccurate during design, but you're correct that it is not really applicable in the real world listening to music. A power level of 1W isn't too aggressive, even on a typical tweeter, and shouldn't push it into higher distortion levels IMO. Pushing 1W, or more accurately 2.83VRMS across the whole audio frequency band to ensure the response is flat or near flat is perfectly acceptable.
            Electronics engineer, woofer enthusiast, and musician.
            Wogg Music

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            • #7
              Originally posted by wogg View Post
              Pushing 1W, or more accurately 2.83VRMS across the whole audio frequency band to ensure the response is flat or near flat is perfectly acceptable.
              But nobody does that(often its just 3 or 4 test tones). Or if they do, the measurement of for example, 90 db at 1watt/1meter, doesn't say how it was measured. And put in a line array, its simply impossible to take the measurement given and get any idea of how it will perform on average music levels in a living room when there are 20 of them instead of two.

              It all seems like trying the catch a greased pig in a swimming pool.

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              • #8
                Originally posted by Sydney View Post
                It's an attempt to set a usable industry standard that can be scaled up or down accordingly.
                Inverse square Law is one variable.
                Yes... it works if you listen to test tones. "I heard this great test tone yesterday at A440. You have just got to hear it."

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                • #9
                  Originally posted by malboro2 View Post
                  ... 90 db at 1watt/1meter, doesn't say how it was measured. ...
                  Actually there are AES standards for testing ( doesn't mean universal compliance ).

                  "Not a Speaker Designer - Not even on the Internet"
                  "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                  Comment


                  • #10
                    Originally posted by fpitas View Post
                    You don't need to run the tweeter at that level to measure sensitivity, it can be measured at a lower level and the output at 1W input extrapolated.
                    You are assuming that changes are linear in a speaker. In electronics, they are, mostly. But speaker's intermodulation distortion and flatness of frequency response changes in a non-linear way to increases in power applied to the contacts. It has resonances; the material is not the same density everywhere; the application of the coatings are not uniform; nothing is linear about a speaker driver. Its a chaotic system dependent on too many variables to do accurate extrapolations. And that doesn't include the listening environment or the ear/brains listening.

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                    • #11
                      Originally posted by Sydney View Post
                      Actually there are AES standards for testing ( doesn't mean universal compliance ).
                      Many of the speaker drivers we get now are made in China. AES may not apply there. And PE does not routinely test drivers in an anechoic chamber.

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                      • #12
                        90db @ 1 Meter translates to 84db @ 2 Meters and 78db @ 4 Meters ( and be sure to include Crest Factor consideration )
                        "Not a Speaker Designer - Not even on the Internet"
                        "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                        Comment


                        • #13
                          Originally posted by malboro2 View Post

                          You are assuming that changes are linear in a speaker. In electronics, they are, mostly. But speaker's intermodulation distortion and flatness of frequency response changes in a non-linear way to increases in power applied to the contacts. It has resonances; the material is not the same density everywhere; the application of the coatings are not uniform; nothing is linear about a speaker driver. Its a chaotic system dependent on too many variables to do accurate extrapolations. And that doesn't include the listening environment or the ear/brains listening.
                          Trust me, at 90dB SPL and below the non-linearities you're talking about are negligible.
                          Francis

                          Comment


                          • #14
                            Originally posted by malboro2 View Post
                            Many of the speaker drivers we get now are made in China. AES may not apply there. And PE does not routinely test drivers in an anechoic chamber.
                            Hence the phrase
                            ( doesn't mean universal compliance ).
                            Though several are attempting to help you understand - yer not getting it
                            "Not a Speaker Designer - Not even on the Internet"
                            "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                            Comment


                            • #15
                              No...Sydney.... I do get it.

                              Its an attempt to establish a universal way to catch a greased pig in a pool, but without defining the size of the pig, the temperature of the water, the physical process of the catcher, and many other variables. Its the reason why one person can review a particular speaker driver here on PE as wonderful, and the next person can say its a piece of shat. The measurements may be stable in themselves, but they really bear no consistent bearing to how a group of people may respond to the particular speaker. You are probably better off reading the people's personal evaluations than looking at the "data".

                              And the bottom line is that I'm trying to define things when I realize that the measurements that I am using may be pretty faulty for the application I am putting the speaker into.

                              Engineers like measurements, but often the measurements cannot even be heard in real life music.

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