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A good tweeter to match 5" SB Acoustics Magnesium Woofers

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  • Originally posted by xmax View Post
    What are some of your favorite albums for evaluating loudspeakers? (or just enjoying yourself)
    All over the map, all types of classical (RCA, Hyperion, etc etc, many good labels) 50s/60s jazz, stoner rock, blues, some punk/heavy, 90s rap, some hip hop.....

    Any recommendations from an engineering perspective, for auditioning speakers?

    Comment


    • The reason I asked: so if you mentioned a few specific artist chances are they work with one or more of my clients
      ​and it might be fun to let you know if my work had touched any of those records.
      Guess xmax's age.

      My guess: 15. His grammar is passable. His trolling is good.

      Comment


      • Originally posted by xmax View Post
        The reason I asked: so if you mentioned a few specific artist chances are they work with one or more of my clients
        ​and it might be fun to let you know if my work had touched any of those records.
        It might be more fun to just say who you are. What Bowie albums are you associated with ?
        craigk

        " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

        Comment


        • Blackstar.
          Guess xmax's age.

          My guess: 15. His grammar is passable. His trolling is good.

          Comment


          • Originally posted by dcibel View Post
            Harmonic spikes based on Fs, what are we on about now? You've successfully shown that something that is louder has higher amplitude, well done. Where amplitude is nearly equal at 3kHz, distortion is equal as well. I still don't see "distortion caused by the resistor" which was your original statement. The tweeter transfer function is as it is to obtain the intended frequency response. With regards to distortion, the tweeter makes as much distortion as it makes any any frequency at the amplitude it plays, regardless of the filter in place. It sounds like you prefer to crossover higher, and would take a "less stressed" tweeter with the narrowing directivity and breakup distortion of the midwoofer over a lower frequency crossover, and that is fine if that's what you want to do.

            You are welcome to have all the opinions you want, but we are not sheep, when you make statements that appear false with an arrogant attitude, be prepared to explain yourself or you will not be taken seriously. We are a community of speaker enthusiasts, people come here to learn and share in a friendly and polite environment, so I would say it is quite rude to call someone's design wrong, bad, poor choices, etc simply because they have made design decisions that don't agree with your design opinions.

            I suggest you take any tweeter design a filter in the 1800 to 2K range listen to it, then add a 6.2 ohm resistor, correct for volume
            listen again. The reason I know this might not be the best way to do it because I have made the same mistake.
            If you take a closer look at this pic you can see the distortion is in fact higher with the resistor at some frequencies.
            Those Frequencies also happen to be harmonics of Fs. If you think this is too low in level to be audible you would be wrong.
            We are all only human and no matter how brilliant 99% of our work is that 1% gets by once in a while.
            Guess xmax's age.

            My guess: 15. His grammar is passable. His trolling is good.

            Comment


            • What is SPL of the passband, and mic distance?

              2 arrows pointing at the noise floor, looks more like harmonics of 60Hz
              "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
              exactly a Fc 3K for both drivers, anybody can do it." -Xmax

              Comment


              • Originally posted by dcibel View Post
                What is SPL of the passband, and mic distance?

                2 arrows pointing at the noise floor, looks more like harmonics of 60Hz
                It was around 98dB, mic was about 1ft away. If it was noise it would be higher
                without the resistor. These are the small things that show up in measurements
                that I have become keen to over many years of doing this and are readily audible. I
                would have never mentioned he might want to steer clear of this design but
                I hate to see a great companies drivers used maybe not in the best possible
                way and then everybody demanded to see proof (and called me a prick lol).
                Guess xmax's age.

                My guess: 15. His grammar is passable. His trolling is good.

                Comment


                • [email protected] is only about [email protected], hardly torturing that tweeter at all.

                  You see how the slope of the roll off flattens out below 400Hz and gets all wiggly, that's how you know you've hit the noise floor. The slope of the response here should be very predictable by the filter applied and the natural slope of the driver.
                  "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
                  exactly a Fc 3K for both drivers, anybody can do it." -Xmax

                  Comment


                  • Spec for a Bruel and Kjaer 4007 mic is 70dB SNR at 94dB SPL, though they only spec at 1kHz. Should be better than what is shown, but it wouldn't hurt to increase drive level a bit.
                    "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
                    exactly a Fc 3K for both drivers, anybody can do it." -Xmax

                    Comment


                    • Interesting, is that resistor after the crossover network?

                      Comment


                      • Originally posted by Billet View Post
                        Interesting, is that resistor after the crossover network?

                        Yes.
                        Guess xmax's age.

                        My guess: 15. His grammar is passable. His trolling is good.

                        Comment


                        • Originally posted by dcibel View Post
                          [email protected] is only about [email protected], hardly torturing that tweeter at all.

                          You see how the slope of the roll off flattens out below 400Hz and gets all wiggly, that's how you know you've hit the noise floor. The slope of the response here should be very predictable by the filter applied and the natural slope of the driver.
                          Again it's only there with the resistor. It would be interesting if you did the same test. And again I am very familiar with the small
                          SB tweeters I have tried to use a similar filter and pad and noticed this happening. It really looks to me there is some aggressive
                          baffle step compensation plus less energy in the 2-3K region (like all SB tweeters) resulting in the use of the resistor to tilt the
                          transfer function. A slightly dirty fix.

                          It is more like 105dB now that I double checked.
                          Guess xmax's age.

                          My guess: 15. His grammar is passable. His trolling is good.

                          Comment


                          • And I'm not saying that very low level information is audible, (directly) I'm saying it is a clue to
                            why the tweeter might sound a little "pokey".
                            Guess xmax's age.

                            My guess: 15. His grammar is passable. His trolling is good.

                            Comment


                            • Agree that looks like the noise floor.

                              It is -60db.

                              Comment


                              • Even if it is (how would a resistor increase noise), distortion is 10dB higher at 1K with the resistor.
                                Moving on...
                                Guess xmax's age.

                                My guess: 15. His grammar is passable. His trolling is good.

                                Comment

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