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How to know tweeter limits

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  • How to know tweeter limits

    I'm looking for a tweeter but most of the time i can't find an Xmax data. If you don't have the tweeters Xmax how do you know how far you can push it ?

  • #2
    You would use maximum wattage. Typically you run out of mid and woofer before the tweeter because the sensitivity of the tweeter is higher. You can model in XSim
    John H

    Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

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    • #3
      Originally posted by jhollander View Post
      You would use maximum wattage. Typically you run out of mid and woofer before the tweeter because the sensitivity of the tweeter is higher. You can model in XSim
      Maybe i'm wrong but this makes no sense because the higher sensitivity of the tweeter only will make it easier to reach it Xmax

      Edit: i see what you mean about wattage to the tweeter but still this only makes it harder to determine it's limits

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      • #4
        With woofers the mechanical limit is often lower than the thermal limit, so it's critical to know xmax. Tweeters tend to be the other way around, so going by the thermal limit usually will suffice.
        www.billfitzmaurice.com
        www.billfitzmaurice.info/forum

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        • #5
          Do a sim in XSim and check the wattage of the system. The woofers reach x-max before you cook the tweeter. This assumes the system has a crossover on the tweeter.

          Why are you concerned?
          John H

          Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

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          • #6
            The "loudspeakerdatabase" website has XMAX for several tweeters.
            It looks like many small 1/2"-3/4" tweeters have ~0.2mm XMAX while some larger 1" dome tweeters have up to 0.5mm-0.8mm, some beyond.

            Some tweeters will list XMAX even on PE (I think) if they think you'll be impressed by the number (looking at you DC28F), otherwise it's probably safe to assume around 0.2mm.
            A lot of software that shows XMAX isn't super easy to work with for the small numbers that tweeters use for...everything, so that can be tricky unless you're one of those wizards who can figure that stuff out with the math instead of with software.
            I'm not smart enough for that, so I arranged a goofy little series of things to let me find how loud and low I can push a few tweeters in VituixCAD...easier for me because I only usually have two that I need to worry about right now.
            My first 2way build

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            • #7
              FWIW I use distortion tests on tweeters to determine tweeter limits at lower frequencies.
              Brian Steele
              www.diysubwoofers.org

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              • #8
                Originally posted by jhollander View Post
                Do a sim in XSim and check the wattage of the system. The woofers reach x-max before you cook the tweeter. This assumes the system has a crossover on the tweeter.

                Why are you concerned?
                Because i want to use the peerless corundum 1 inch with 0.7 xmax but for my needs i have to use all it's excursion there is. The off axis isn't great so i was looking for a other tweeter with better off axis. I saw a dayton 1 inch tweeter with 80 watt RMS so if it has ( almost ) the same Xmax as the corundum i could use 2 off them because they are smaller.

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                • #9
                  Originally posted by Brian Steele View Post
                  FWIW I use distortion tests on tweeters to determine tweeter limits at lower frequencies.
                  This seems legit but you have to buy the tweeter first

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                  • #10
                    Originally posted by LOUT View Post
                    The "loudspeakerdatabase" website has XMAX for several tweeters.
                    It looks like many small 1/2"-3/4" tweeters have ~0.2mm XMAX while some larger 1" dome tweeters have up to 0.5mm-0.8mm, some beyond.

                    Some tweeters will list XMAX even on PE (I think) if they think you'll be impressed by the number (looking at you DC28F), otherwise it's probably safe to assume around 0.2mm.
                    A lot of software that shows XMAX isn't super easy to work with for the small numbers that tweeters use for...everything, so that can be tricky unless you're one of those wizards who can figure that stuff out with the math instead of with software.
                    I'm not smart enough for that, so I arranged a goofy little series of things to let me find how loud and low I can push a few tweeters in VituixCAD...easier for me because I only usually have two that I need to worry about right now.
                    i can't find Xmax data about the DC28F, i guess you mean the dayton, there are 3 off them with no data. There is a site where you can calculate Xmax for piston erea, SPL and frequency so that's what i use.

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                    • #11
                      Originally posted by Scarface1 View Post
                      ...but for my needs i have to use all it's excursion there is...
                      Any chance you can elaborate on what these needs are?

                      Originally posted by Scarface1 View Post
                      i could use 2 off them because they are smaller.
                      That wont work. Research comb filtering.
                      Constructions: Dayton+SB 2-Way v1 | Dayton+SB 2-Way v2 | Fabios (SB Monitors)
                      Refurbs: KLH 2 | Rega Ela Mk1

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                      • billfitzmaurice
                        billfitzmaurice commented
                        Editing a comment
                        It will work, provided they're vertically aligned and the frame size isn't overly large. Lobing on the vertical plane might be an issue if the listening distance is closer than where the outputs have integrated into a single wavefront, but since he's concerned about high SPL I doubt that's the case. Still, it would be helpful to know what he's trying to achieve to be able to render an informed opinion.

                      • Scarface1
                        Scarface1 commented
                        Editing a comment
                        Comb filtering don't occur right? Because at 2500hz the 2 tweeters have to be 3,4 cm from each other to make this happen. You mean the +3db when they are in phase right?

                    • #12
                      This must be a unusual application. Tweeter xmax is not required for design. Tweeter off axis response needs to be considered with respect to the mid range and crossover point.
                      John H

                      Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

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                      • #13
                        I want to build a boombox with 2 epique e150HE and dsp, so with highpass added and max power it should get pretty loud, like 112 db RMS and 115 db peak. Because i have to make room for batteries, amps and modules i only have a few options to make it work. I will update a screenshot later of the sketch.
                        i'm not sure i will build this but if it's possible and i know for sure everything will work out well, i think i do

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                        • #14
                          Those woofers are only good for 106dB each, so tweeters that will keep up with them shouldn't be all that difficult to find, especially if they have 6dB or more better sensitivity than the woofers.
                          www.billfitzmaurice.com
                          www.billfitzmaurice.info/forum

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                          • #15
                            Originally posted by billfitzmaurice View Post
                            Those woofers are only good for 106dB each, so tweeters that will keep up with them shouldn't be all that difficult to find, especially if they have 6dB or more better sensitivity than the woofers.
                            Yes but i use 2 woofers and 1 tweeter like a mtm so it will be 112db for 1 tweeter. Those woofers off axis begin to get worse at 2500hz so i was thinking about a steep roll of. Because there is some baffle step i could play it to 115 db before the limiter kicks in.

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                            • Scarface1
                              Scarface1 commented
                              Editing a comment
                              Why should i not worry about the dispersion on a boombox?

                            • jhollander
                              jhollander commented
                              Editing a comment
                              The off axis response will be dominated by the interaction between the two horizontal woofers.

                            • Scarface1
                              Scarface1 commented
                              Editing a comment
                              Do you mean that the waves between the woofers will build up so the energy is more forced to go forward
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