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  • #31
    So every speaker i calculate in winisd i have to take 6db off? If i look to other speaker builds like the diamondboxx M they can go crazy loud wich is not possible if you also have to take 6 db off it.
    I understand that a baffle ads nothing to it, it's just the backwaves of the speaker bouncing back.

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    • #32
      Originally posted by Scarface1 View Post
      So every speaker i calculate in winisd i have to take 6db off? If i look to other speaker builds like the diamondboxx M they can go crazy loud wich is not possible if you also have to take 6 db off it.
      I understand that a baffle ads nothing to it, it's just the backwaves of the speaker bouncing back.
      No, the front wave diffracts around the box at low frequencies and gets partially lost.
      Francis

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      • #33
        The driver/woofer measurement you see (and the DB/sensitivity data given) is taken with a woofer mounted against a HUGE baffle. This gives consistent data, but it also means the real-world build using the woofer can have a ~6db falloff somewhere below 500-1000hz...maybe even starting at higher frequencies if the baffle you'll use is very narrow or small.


        In other words, when the E150HE shows itself as ~83db sensitive at 2.83v, that's only if you have it mounted to a roughly 8ft-wide (and tall) baffle. A smaller baffle will result in less bass volume and less low-mid volume.
        You can get around this if you mount the drivers in-wall...or if you don't really care about the speakers sounding a bit thin and top-heavy, but it's something you're otherwise pretty stuck with and most/all driver-measurement data shown will follow this pattern (as far as I know).
        Last edited by LOUT; 01-31-2022, 05:58 PM. Reason: was using "speaker" and "woofer" interchangeably, which could be confusing. Hopefully this is less-so.
        My first 2way build

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        • #34
          Ok, i understand. So every speaker manufacture measures this way? If you buy a bleutooth speaker they can get very loud on paper but this is probably with the speaker against a big wall or like just mentioned with top heavy sound.

          I want to have a full body sound and i think there is nothing that change for me beside a 6db overal loss. I already calculated the baffle step response but saw it as a 6db gain in the upper frequencies instead of a 6db loss in the lower frequencies!

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          • DeZZar
            DeZZar commented
            Editing a comment
            Manufacturers of finished speakers can pretty much quote whatever they want to but generally speaking they should be quoting you the specifications AFTER all their engineering is done so you don't need to go looking at speaker specs and minus away baffle step. I would say a 120db claim from a 2-way stereo boom box is pretty generous and if you read between the lines of their specifications, they are manipulating the bass output as you turn it up so the woofers don't kill themselves....120db is probably some peak in the frequency range somewhere after pulling ~15+db out of the lower bass frequencies with an active eq.

        • #35
          It's all relative ...

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          • #36
            Originally posted by Scarface1 View Post
            I already calculated the baffle step response but saw it as a 6db gain in the upper frequencies instead of a 6db loss in the lower frequencies!
            If you were looking at things that way, wouldn't you end up seeing most/all 1"-1.5" tweeters reaching 110-113db easily (after adding +6db onto their spec'ed 104-107db peaks)? Or were you only adding the upper frequency boost to the woofers and not the tweeters?

            My first 2way build

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            • #37
              Originally posted by LOUT View Post
              If you were looking at things that way, wouldn't you end up seeing most/all 1"-1.5" tweeters reaching 110-113db easily (after adding +6db onto their spec'ed 104-107db peaks)? Or were you only adding the upper frequency boost to the woofers and not the tweeters?
              I added 6db gain but when i used a online Xmax calculator i forgot it. So i tought about getting 112db and put it in the calculator with a very high xmax as result. Later i took of 6db because of how i tought baffle step worked and indeed this way i easely could get high spl like you mentioned.

              But there is no 6db baffle step gain but also the bass region got 6 db lower because of baffle step loss so i have to aim for an overal 106db spl! To reach this i still need 40 watt RMS for the tweeter and for an + 3db ,because baffle step start to 'rise' at 300 hz and i need the tweeter to take over at 2500 hz at the same loudness so i need 80 watt RMS so that's why i want to use 2 tweeters for some extra room for power. At 300 hz the loudness contour begin to play a role so i need less output above 300hz to still get that full body sound. So basically i want to do the same as manufactures do, cutting of the low bass at high volumes and let the higher notes even play a bit louder( +3db )

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              • #38
                I try to make a sketch of the build this week and a simulation for the frequency response etc.

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                • #39
                  Originally posted by Scarface1 View Post
                  i have to aim for an overal 106db spl! To reach this i still need 40 watt RMS for the tweeter and for an + 3db ,because baffle step start to 'rise' at 300 hz and i need the tweeter to take over at 2500 hz at the same loudness so i need 80 watt RMS so that's why i want to use 2 tweeters for some extra room for power.
                  The pair of E150HE woofers reach ~106db (after full BSC) at ~400watts/each-side. With bass-limiting/protection you might choose to push them to 109db in short bursts using ~800watts/each-side.

                  The Dayton RST28F/RST28A tweeter can reach ~108db at rated wattage, and may reach ~111db in short bursts with appropriate HighPass.
                  The DSN25F-4 can reach ~107db, and may reach ~110db in short bursts with appropriate HP.
                  The planar PT2C-8 should be able to cross at 2500hz or lower and can reach over 109db at rated wattage.

                  IF you're counting the woofer pairs at +3db for temporarily pushing them in short bursts to double their wattage handling, then you can also do the same for the tweeter (assume a temporary +3db at twice the rated power-handling).
                  Or, in the case of the PT2C-8, it can keep up with the woofer pairs' 800watt bursts simply at its rated power.
                  Is your amplifier and power-delivery for it able to push ~800+800watts?


                  I don't mean this as a push specifically for Dayton, it's just a convenient source. I'm sure there are several good tweeter options that can keep up like this without anything special.
                  Thanks for taking the time to explain how the earlier mixup happened.
                  My first 2way build

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                  • #40
                    LOUT no problem, thank you ( and others ) for the help. I think the peerless 1inch corundum is the best solution. It has a 100 watt RMS power handling and a 89db sensitivity, so 109db MAX and 112db short burst ( peak ).

                    I want to use a 750 watt RMS x 2 amp and a 200 watt RMS amp for the tweeter.

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                    • #41
                      Did you want to use two different amps because you're using an active crossover at the preamp, or is there another reason for different woofer/tweeter amps?

                      I could easily be wrong (because I don't understand....anything, terribly well) but I think powering a single 750x2 amp would be more efficient for your battery-bank compared to powering both a 750x2 (for woofers) and a 200x2 (for tweeters). Though I'm honestly not sure if the different amps working together means higher power-draw when they're frequency split VS using a single amp with a passive XO for HighPass/LowPass.
                      You'd still be able to do the bass protection DSP wizardry either way.
                      My first 2way build

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                      • fpitas
                        fpitas commented
                        Editing a comment
                        Typically driving a class D amp at higher levels is more efficient. So, one amp *might* be more efficient. However, unless there is something terribly odd about the music being played, 99% of the power will go to the woofers, one way or another.

                      • Scarface1
                        Scarface1 commented
                        Editing a comment
                        Yes i want to use a dsp pre amp, the dayton dspb-k. It's a very small module with 3 channel output and as far as i know should be able to add all the dsp stuff i need. It cost a bit extra energy but a lot easier i think because i don't know much about passive crossovers ,it is a lot cheaper i guess and it takes less room.

                      • Scarface1
                        Scarface1 commented
                        Editing a comment
                        The tweeter amp have 4 watt idle and the woofer amp have 18 watt idle so it's a fair compromise i think

                    • #42
                      Is power-draw near max output with music or white-noise about the same when split between two amps(bi-amp) VS one amp(w/XO)?
                      That's the main part I was wondering, if somehow a 400Wx2 and 100Wx2 bi-amp setup at full power meant higher or lower or similar draw from the battery (or wall) VS a 400Wx2 with XO.

                      For whatever it's worth, I think you can simply use an inductor and capacitor on the woofer and cap+ind on the tweeter, then use the preamp's DSP to shelf the highs above 1Khz by -8-10db, instead of using resistance in a HighPass.
                      I think the single amp and small XO ends up saving some money compared to bi-amp (around $20-50 for all XO parts VS whatever the 200x2 amp costs), but I'm pretty sure bi-amp should take up less space AND gives more flexibility for what you can do using the preamp's DSP.

                      Sorry about harping on this. I really don't mean it as an argument for or against anything at this point. I'm mostly trying to wrap my own mind around it, and was curious if the LP/HP-shelf plus simple passive XO without resistance could work..so talking aloud about it as I mess with it in sim.
                      My first 2way build

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                      • Scarface1
                        Scarface1 commented
                        Editing a comment
                        I'm happy you harping about this because i want the best solution so every option is worth thinking off. A second smaller amp for the tweeter is about 50$ and should consume the same energy i guess beside the idle wattage of 4 watt but that's not really a big deal i think because on the other hand it is really easy to add crossovers and stuff with dsp and it also save weight. So i'm not sure but i think the extra amp for 50$ is an easy choice ?

                      • LOUT
                        LOUT commented
                        Editing a comment
                        Assuming there aren't any crazy unforseen disadvantages (I'm guessing powering the two separate amps can be done in a somewhat unified or otherwise elegant way), I'd have to agree that the two amp version seems to be holding all the positives...and the price sounds comparable.
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