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  • PA Subwoofer?

    I'd like to build a PA double 18 subwoofer that plays low end down to 30hz. 20hz would be better but it takes more to get there and I'm not really interested in folded horn designs due to delay paths amongst other issues that I dislike for live PA playback.

    I already own a fair bit of PA gear but its all different models so I'd like to get rid of them and create a "wall of sound" made of uniform, matching cabs.

    Yes I'm aware I could buy two subwoofers, bridge my ep4000 and get the same spl/db as multiple of the weaker drivers. However I have unlimited storage, so having less drivers for a higher cost does absolutely nothing to benefit me aside of look like less of a impressive wall of sound. I also have access to a wood shop with direct access to pallets of wood so I'm getting birch for as cheap as most people get mdf.. may as well be free. From looking at the g-sub plans it would cost me less then $100 to create one without the drivers, including metal corners, handles ect.

    What I was debating on doing was building some G-Subs with the dayton audio PA460-8 or the rockville RVP18W8 or rockville RVW1800P4. The main reason why I'm choosing these drivers is since they are drivers under $100/each and they are not discontinued or on blow out. I was looking at the b52's they got on blowout here on parts express for $75/ea but they are 4ohm is the main reason why I thought they wouldnt be a good fit. The main reason why I choose the G-Sub over folded horns or bandpass designs is since I'm looking for monitor quality bass response, so bass reflex cabs while not creating the most spl/db they do have one of the most responsive and clear sounds, with zero delay or horn paths between them and your highs or the rest of the system. I'm open to other case designs but my requirements are that they need to be stackable, so a dual-18 design makes more sense since its basicly already stacking two. I'd like to eventually have 8x subs in 4x cases powered by the ep4000 into dual 2ohm at 1250w split into rms 312w/ea speaker (4 peaker/2 cab each side), stacked/coupled together in a single wall.

    My question is if the dayton audio PA460-8's are worth buying for this type of cab design? I noticed that they seem to have a 2 chamber design on the parts express page and really I don't want to build that.

    Alternatively I'm open to other suggestions, but my requirements are that the driver be between 300w-600w since I already own a ep4000 (more or less the same thing as a ep2500) and I'd ideally like to power 8 of these drivers off this one amp since it has dual channels of 1250w at 2ohm. That gives roughly 312w/ea speaker so ideally I'd be looking for a high efficiency 350-400-450w driver. Peavey has the 1801-8 LT blackwidow 18's that look good since they have low hz range and at 350w I'd be able to push them pretty good on this amp at 2ohm.. However I'm wondering if the nearly double price tag is legitimately worth it, for example would the blackwidow have higher spl/db with the same 312w since its closer to its 350w max then the dayton audio PA460-8 since its a 500w speaker and would be farther away from its max due to only getting 312w? Or what about the rockvilles at 600w at 900w, would they be as loud per watt or be more quite due to being farther away from their max rms power aka pushing it fully?


  • #2
    Looking at the G-Sub plans I noticed that the recommended drivers are not on the cheapest end of the market.
    Opinion: Considering that you are saving a lot on wood - I'd not scrimp on drivers, particularly if these would be driven hard or part of a contract sound provider service .
    Robust drivers pay back in longevity
    "Not a Speaker Designer - Not even on the Internet"
    “Pride is your greatest enemy, humility is your greatest friend.”
    "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

    Comment


    • #3
      Try to run a sim for a 6th order box for them I have a very old. Late 80’s early 90’s muse model18 sub that’s a 6th order box It was the very first commercial available for home use powered subs that went down to 20hz and lower. Well it will go down to 11hz And it only uses two 10” perless drivers and a 125 watt plate amp. But the box does weigh in at 176lbs. Lol. You could also do a tuba sub box. You can make them tall with a small foot print I made one with 8 feet of horn path and used the Dayton Audio 15” mkII sub driver. That baby would blow the windows out of my house. I did the REW spl test on it and with 1 watt at 1m I was getting 102db. And with my Yamaha p5000s amp bridged in mono I did a few full power test, I only did this 3 times and stoped after cracking my sliding glass door window that was over 30 feet away from the sub. Lol I got up to a 135db and it would go down to 14hz with 115db The 135db was in the 24 to 36hz range And just like the muse it was a beast of weight of 130lbs. That was because the long sides of the box i made them in 2” mdf. And the motor board was 1.5” thick. Just thinking outside the box here. Lol You could go the old school way of making the sugar scoop box with two drivers or single driver You may also want to make two different types of boxes, one for your really low hz , say from 12hz to 25hz and the other box to go from 23hz up to 100 hz and this one would need less power as the first one would need a lot more You can pm me and I can give you some ideas with more info from you Back in the early 90’s I was a live sound tech and had a 30,000 watt PA for out doors and inside for the bars I would only run around 3000 watts. And I built all my speaker cabs using Klipsch and EV pro type plans. You can email EV and they will give you the blueprints of the boxes for any driver you want that they make or used to make, and most of them work very well with the Dayton Audio line of drivers

      Comment


      • #4
        Do you model boxes? ( WinISD from linearteam.org - the "Pro" vers.)

        In that "G-sub" (I get 11.8cf, 11.3 subtracting out the slot structure) the PA460 won't do 40Hz (like the other listed drivers) probably due to its lower Q.
        It should do close though (43-44?). There's nothing special about that dual 18 box, it's just a slot-ported vented box (not slot-loaded).
        They'd be Xmax-limited to 600w (for a pair). Still, it looks like 125dB or so @ 45Hz.

        For a (single) PA460 to hit 30Hz, it needs 16cf tuned to 33Hz (per EACH).

        Comment


        • #5
          Originally posted by Chris Roemer View Post
          Do you model boxes? ( WinISD from linearteam.org - the "Pro" vers.)

          In that "G-sub" (I get 11.8cf, 11.3 subtracting out the slot structure) the PA460 won't do 40Hz (like the other listed drivers) probably due to its lower Q.
          It should do close though (43-44?). There's nothing special about that dual 18 box, it's just a slot-ported vented box (not slot-loaded).
          They'd be Xmax-limited to 600w (for a pair). Still, it looks like 125dB or so @ 45Hz.

          For a (single) PA460 to hit 30Hz, it needs 16cf tuned to 33Hz (per EACH).
          So what your saying is if I had multiple singles I'd be able to go lower then the duals?

          I do use winISD however I'm still trying to learn whats all the stats mean, I know folks that can look at a sub and know what type of box it would be good for by the different stats on it.

          Another idea I was thinking about was upgrading the size of the g-sub and possibly getting 21's. Alternatively if I used 21s, that opens up the ability to build something like 18sounds bandpass dual 21 that I think could be pretty cool.

          I found these drivers for pretty cheap but I'm not finding the model number of them so heres the specs. First thing that stood out to me was 26mm xmax could move alot of air haha.

          Specifications:
          Nominal diameter 21 inch
          Nominal impedance 8 Ω
          Power rating 1000 W
          Sensitivity (1w/1m) 100 dB
          Frequency range 22-900Hz
          Voice coil diameter Φ125 mm
          Basket Die Cast Aluminium
          Cone and dust cap Paper
          Surround Cloth
          Voice coil wire In/Out Copper
          Voice coil former Glassfiber
          Winding depth 40mm
          Magnet Neodymium
          Thiele-Small Parameters
          Fs 22 Hz
          Re (D.C.) 5.2Ω
          Qms 19.10
          Qes 0.59
          Qts 0.57
          Vas 208.5 L
          Cms 0.05 u M/N
          Bl 27.9 T
          Xmax 26mm
          Mounting information
          Overall diameter 548mm
          Bolt Circle Diameter 525mm
          Baffle Cutout Diameter--Front Mount 505mm
          Overall Depth 275mm
          Net weight 14.1kg

          Comment


          • #6
            Originally posted by carlthess40 View Post
            Try to run a sim for a 6th order box for them I have a very old. Late 80’s early 90’s muse model18 sub that’s a 6th order box It was the very first commercial available for home use powered subs that went down to 20hz and lower. Well it will go down to 11hz And it only uses two 10” perless drivers and a 125 watt plate amp. But the box does weigh in at 176lbs. Lol. You could also do a tuba sub box. You can make them tall with a small foot print I made one with 8 feet of horn path and used the Dayton Audio 15” mkII sub driver. That baby would blow the windows out of my house. I did the REW spl test on it and with 1 watt at 1m I was getting 102db. And with my Yamaha p5000s amp bridged in mono I did a few full power test, I only did this 3 times and stoped after cracking my sliding glass door window that was over 30 feet away from the sub. Lol I got up to a 135db and it would go down to 14hz with 115db The 135db was in the 24 to 36hz range And just like the muse it was a beast of weight of 130lbs. That was because the long sides of the box i made them in 2” mdf. And the motor board was 1.5” thick. Just thinking outside the box here. Lol You could go the old school way of making the sugar scoop box with two drivers or single driver You may also want to make two different types of boxes, one for your really low hz , say from 12hz to 25hz and the other box to go from 23hz up to 100 hz and this one would need less power as the first one would need a lot more You can pm me and I can give you some ideas with more info from you Back in the early 90’s I was a live sound tech and had a 30,000 watt PA for out doors and inside for the bars I would only run around 3000 watts. And I built all my speaker cabs using Klipsch and EV pro type plans. You can email EV and they will give you the blueprints of the boxes for any driver you want that they make or used to make, and most of them work very well with the Dayton Audio line of drivers
            You have any pictures?

            Comment


            • #7
              Originally posted by SaintZoilus View Post
              You have any pictures?
              Sadly no. The camera that add all my old audio pics and videos on it some how got to close to some 18” sub drivers and the magnets had a field day with it and toasted the camera and everything on it. I think I may have a sketch or drawing of it on the website that I got the idea for it I’ll have to look on my iPhone cloud drive and see if any of them where saved there

              Comment


              • #8
                Originally posted by carlthess40 View Post
                Sadly no. The camera that add all my old audio pics and videos on it some how got to close to some 18” sub drivers and the magnets had a field day with it and toasted the camera and everything on it. I think I may have a sketch or drawing of it on the website that I got the idea for it I’ll have to look on my iPhone cloud drive and see if any of them where saved there
                Daaamn dude I'm sorry to hear that. I've heard of folks laptops getting rekt but thats something iv never heard of before

                Comment


                • #9
                  Originally posted by SaintZoilus View Post
                  I already own a ep4000 (more or less the same thing as a ep2500) and I'd ideally like to power 8 of these drivers off this one amp since it has dual channels of 1250w at 2ohm.
                  Haven't we covered this already? If you try to run that amp at 2 ohms into subs it will shutdown. This amp is a shameless copy of tthe QSC RMX2450 except that Behringer cheap'd out on the power supply with a smaller transformer and less storage capacitance, the QSC is well known for not being able to do what you plan and knowing this QSC built a modified version with more heatsink capacity designed specifically for 2 ohm operation called the RMX1850HD. So given all that why don't you pickup anther Ep4000 and run both at 4ohms per channel.
                  Paul O

                  Comment


                  • #10
                    Originally posted by Paul O View Post
                    Haven't we covered this already? If you try to run that amp at 2 ohms into subs it will shutdown. This amp is a shameless copy of tthe QSC RMX2450 except that Behringer cheap'd out on the power supply with a smaller transformer and less storage capacitance, the QSC is well known for not being able to do what you plan and knowing this QSC built a modified version with more heatsink capacity designed specifically for 2 ohm operation called the RMX1850HD. So given all that why don't you pickup anther Ep4000 and run both at 4ohms per channel.
                    If your legitimately trying to help can you elaborate on what exactly the issue is?

                    I ask since I own multiples of these amps and have been running them at 2ohm for years without any issue what so ever. I have a ep2500 I've had for over ten years now (same thing as the ep4000) thats been used countless times for 12+ hour periods without issue, multiple 36+ hour periods without issues.

                    I mean I can get the hate on them for making a copy of the qsc but lets not spread missinformation about 2ohm, it is perfectly fine to be ran at 2ohm in both sub and full range. Sometimes I do both on the same amp in mono, one channel as subs, other as mains.

                    They are good amps. Even if you disagree, I'm not sure what it matters I use to power things on my end, I mean look at this another way, I already own them, why not put them to use?

                    Comment


                    • #11
                      Originally posted by SaintZoilus View Post
                      ...I mean I can get the hate on them for making a copy of the qsc but lets not spread missinformation about 2ohm,..
                      Can't speak for Paul, but my guess it is more of a matter of friendly advice rather than "hate".
                      From an engineering standpoint there are reasons to avoid low impedance loads.

                      "Not a Speaker Designer - Not even on the Internet"
                      “Pride is your greatest enemy, humility is your greatest friend.”
                      "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                      Comment


                      • #12
                        Yes just trying to help not hate. Back when the Ep2500 was newish a bench test was done and the amp would shut off when driven into a 4ohm load bridged, this test was with sine waves which was the standard back in the day but that is a really tough test for an amp at low frequencies in particular so not surprising that a budget amp couldn't do it. Lots of people seem to be able to use this amp at 2 ohms stereo or bridged into 4 ohms without much issue but there are others that have problems with it, which suggests it comes down to the load being driven and the program material.. is it something with sustained bass tones or something more dynamic.. the amp will work fine for one combo but not another. So that is a long winded way of saying what you have may work but introduce different drivers and it may not work anymore. The fact you have a bunch of random drivers may actually be the reason it works as the combined impedance load evens out over the spectrum, but put all the same drivers in there and the impedance minima will be at the exact same frequency and that may be enough to start causing problems. There are good reasons to use the same drivers of course, it vastly simplifies EQ and the system as a whole should sound tighter and more dynamic so don't give up on that idea, and there is nothing wrong with trying it out on 1 amp, if it's stable good enough but if not you get roughly the same power into 2 drivers at 4-ohms per channel so other than making your amp rack a little heavier and wallet a bit lighter the system will produce the same SPL.
                        Paul O

                        Comment


                        • #13
                          this
                          cheap'd out on the power supply with a smaller transformer and less storage capacitance,
                          caught my eye.
                          The Supply is always important.
                          The decision to go "low" is always predicated on the possibility of getting more power. One inevitable consequence is increased current demand and additional heat.
                          Heat in Voice Coils results in Power Compression and "value" drift.
                          Heat in Semiconductors causes shortened device life.
                          Granted High Wattage numbers are enticing, but since loudness isn't additive - 2x the power doesn't mean a significant increase in apparent loudness, especially considering the effects of Compression Loss. And when Amplifiers are at maximum their distortion is highest, often amps at low impedance have even higher distortion.
                          Since Xmax is a 10% distortion figure, that ( for me and others ) isn't a usableTarget. Without benefit of Large signal Data ( like Klippel ) to get real performance data, I set safely below Xmax
                          http://sound.whsites.net/articles/pwr-vs-eff.htm
                          Last edited by Sydney; 11-12-2018, 04:30 PM.
                          "Not a Speaker Designer - Not even on the Internet"
                          “Pride is your greatest enemy, humility is your greatest friend.”
                          "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                          Comment


                          • #14

                            Should also be noted that I generally run my stuff outdoors during the night time so I may be less susceptible to heating issues that people indoors inside of a club or hot venue might have, due to the cool air conditions I always run them under. I'll run 2ohm loads on 3 amps stacked ontop of each other with a driverack 260 ontop and all 3 amps will be pushing cold air out of them and only be slightly warm to the touch at best. I had one that was warming up on me, I opened it up, cleaned it out with a can of air and it runs cold again. I think anyone who abuses one of these amps and doesn't keep a eye on them could easily blow one, if I had continued to run that hot one without cleaning it out, I'm sure it would've been damaged due to how hot it got, so maybe folks just don't clean their **** and run them indoors with mass body heat buildup? I have no idea, but I have a amp thats ten years old that I run at dual - 2ohm every time without issues.

                            This is all interesting to talk about but what I really wanted to talk about was different cab designs and budget subs, not amps that I already own.

                            When using winisd would it be a 6th order bandpass to try and put in the 18sound dual21 bandpass sub? Or should I be trying different software for this?

                            I ask since its kinda different, since its two back chambers and one huge port combined middle chamber where the drivers fire at each other then out the port, so I tried putting the measurements into winisd with a 6th order box but I'm not sure if this is correct. I calculated the total liters of the "back chamber" by using the mm given by 18sounds plans till I had mm3 volume, then converted that to liters. I did the same thing for the front "chamber" if you can even call it that, its nearly as deep as it is wide and tall so its more of just a front area so thats why it begs the question of if this is a 6th order or a dual bass reflex pointed at each other?

                            I'm going to try and get some free time today to toss the gsub into winisd with the rockville drivers and dayton drivers, problem is they are not already in the library so i have to manually add them and as we all know winisd is kinda picky sometimes and not every company gives exact enough specs.

                            Comment


                            • #15
                              That's not it (the issue entering stuff into ISD) at all. You need "autocalc parameters" turned on, and just enter: Qes, Qms, (NOT Qts), Fs, Vas, Re, Le, Sd, Xmax, and Pe. ISD will do the rest.

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