Hi all,
I'm thinking of using some 12 inch drivers I have to build multi-driver boxes. For this particular project, I'm thinking sealed. Each driver is happy in about 2 cubic feet of sealed volume. I'm trying to decide if I'm ok to do a single 8 cubic foot box with 4 drivers sharing the volume wired in parallel/series for a final 4 ohm load; or if I'm better off having each driver in its own 2 cubic foot space sealed from one another and wiring them the same way (but externally to each other for access). Does it particularly matter to have the drivers share volume vs being sealed from one another in a completely sealed enclosure? Ultimately in mind is toying with the idea of building two to four 8 cubic foot sealed enclosures with 4x 12" drivers each. I have lots of these drivers (the infamous JBL $29 drivers that go on sale annually), so just playing around with more builds with them.
Thoughts?
Experiences with the same?
Very best,
I'm thinking of using some 12 inch drivers I have to build multi-driver boxes. For this particular project, I'm thinking sealed. Each driver is happy in about 2 cubic feet of sealed volume. I'm trying to decide if I'm ok to do a single 8 cubic foot box with 4 drivers sharing the volume wired in parallel/series for a final 4 ohm load; or if I'm better off having each driver in its own 2 cubic foot space sealed from one another and wiring them the same way (but externally to each other for access). Does it particularly matter to have the drivers share volume vs being sealed from one another in a completely sealed enclosure? Ultimately in mind is toying with the idea of building two to four 8 cubic foot sealed enclosures with 4x 12" drivers each. I have lots of these drivers (the infamous JBL $29 drivers that go on sale annually), so just playing around with more builds with them.
Thoughts?
Experiences with the same?
Very best,
Driver pairs can be used for vibration cancellation, but separate boxes are better for diversifying your subs position in the room. No, a divider between multiple drivers in the same box will not have a significant effect.
So, aside from being able to move several boxes into several positions, there's no particular issue with putting 4 drivers in one sealed box that all share the same net internal volume? I already have other subs, these would be smaller array modules to have fun with. I don't have sealed subs, and figured I'd play with sealed surface area for once. I was just wondering if it would matter for driver modeling and/or actual results if I had them sharing a single enclosure vs building 4 separate sealed enclosures with a single driver in each one, stacked up or just lined up together. I would prefer to just build a single enclosure per array of 4 drivers; but if individual separate boxes lined up or stacked together is somehow better, I'm not opposed to that.
Very best,
Very best,
Divide your set of woofers into pairs and nuild that many woofers.
Push-push dramatically reduce the vibrational load on the box, but having at least 2 subs (properly placed) is important for more even LLF evenness thru-out the room
dave
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if your box is sufficently large in one dimension or more you can have a resonant mode that is hard to damp and affects the frequency response. At one point I had 4*15" driver boxes about 1.7m tall and these had a noticable issue in the frequency response and impedance curve. Splitting into pairs is what I would do.
Thanks all,
These will be in addition to subs I already have in the room, response is flat currently. These are just being considered to add the to system for "more." Because, "more!" right? And again, I'm thinking if I have 16x of these drivers in sealed boxes, that's a lot of surface area, maybe I can add a little more to my low end, or just raise SPL in general for less power (rather than adding 2 more drivers with high power needs). Again I already have the drivers. I've made other things with them too, like open baffle wedges, mid-bass modules, etc. Now I'm curious about lots of them in sealed boxes for low end bass.
If I split them into dual sub pairs, I would think it would still be good to wire 4 of them since they're 4 ohm subs, single voice coil, so I can get a final load of 4ohms to be friendly to all amps (instead of 2ohm and 8ohm, 8ohm would work if it had to).
I'm certainly open to the idea of push-push. I've never built a multi-driver sub before. I have several large subs that I built, but they're all ported and low tuned (movie subs). I really would love to look at an array of subs standing tall in the corners or mid-walls. Or I like the idea of a chest enclosure that can sit mid-wall, behind seating, anywhere, with several drivers in it.
I realize if I have one long panel in the enclosure I'm opening up to modes in the box. A 58~60 inch long enclosure that is 20 inches and 16 inches for dimensions for example is a long skinny box. I'm not sure which frequencies will become problematic with those dimensions, just as an example.
So given that, is it going to be much better to have 8x different boxes in push-push with 2 drivers each? Or would it be ok to have 4x boxes with 4x drivers each and well braced? I'd rather build less boxes than more boxes, but if it is a big deal and significantly better to avoid a long panel enclosure for the ranges of the subs, I'm open to anything really.
Very best,
These will be in addition to subs I already have in the room, response is flat currently. These are just being considered to add the to system for "more." Because, "more!" right? And again, I'm thinking if I have 16x of these drivers in sealed boxes, that's a lot of surface area, maybe I can add a little more to my low end, or just raise SPL in general for less power (rather than adding 2 more drivers with high power needs). Again I already have the drivers. I've made other things with them too, like open baffle wedges, mid-bass modules, etc. Now I'm curious about lots of them in sealed boxes for low end bass.
If I split them into dual sub pairs, I would think it would still be good to wire 4 of them since they're 4 ohm subs, single voice coil, so I can get a final load of 4ohms to be friendly to all amps (instead of 2ohm and 8ohm, 8ohm would work if it had to).
I'm certainly open to the idea of push-push. I've never built a multi-driver sub before. I have several large subs that I built, but they're all ported and low tuned (movie subs). I really would love to look at an array of subs standing tall in the corners or mid-walls. Or I like the idea of a chest enclosure that can sit mid-wall, behind seating, anywhere, with several drivers in it.
I realize if I have one long panel in the enclosure I'm opening up to modes in the box. A 58~60 inch long enclosure that is 20 inches and 16 inches for dimensions for example is a long skinny box. I'm not sure which frequencies will become problematic with those dimensions, just as an example.
So given that, is it going to be much better to have 8x different boxes in push-push with 2 drivers each? Or would it be ok to have 4x boxes with 4x drivers each and well braced? I'd rather build less boxes than more boxes, but if it is a big deal and significantly better to avoid a long panel enclosure for the ranges of the subs, I'm open to anything really.
Very best,
If separated up into pairs, how would you think to wire these externally? Just put binding posts on the boxes for each driver so they can be accessed externally? Then be able to just wire up in any config like series/parallel for a gang of 4 subs on one amp with a 4ohm load basically? Won't be as clean as all internal I guess, but I can live with it.
Very best,
Very best,
its pretty easy to work out your lowest frequency mode. It's going to be where there are two minima at the ends of the 'pipe' and a maxima in the middle so half a wavelength. For 60" ~ 1.5m lambda/2 = 115 Hz so this is potentially problematic. You could just divide the box internaly in two to prevent this if you wanted one box.
Dual speakon connector plates (NL4) give you a lot of wiring options. (also better than some 1920's style bare wire.... )
Thanks, very helpful!
I also wonder, maybe I'm going about the question incorrectly. Maybe I really should be asking how to add to my current system based on my current system with these drivers, if at all.
I currently have two moderately large subs (DIY) that are front and rear placed in the room, with no nulls. They're bass reflex tuned at 20hz.
Here's my listening position response after EQ and house curve applied in MiniDSP HD, with zero smoothing applied.
I'm primarily wondering if I can add anything to fill in the range under 19hz. I probably should have started with this question first. Since I have lots of these JBL drivers, I was thinking if I ganged a bunch of them up, it would add up to be a lot of surface area or cone surface and it would then minimize the need for excursion and minimize distortion and require overall less power to get higher SPL that is pretty clean. I was thinking with as many as 16 of these drivers, I might be able to fill in some of that sub-19hz area, if in sealed boxes. Rather than getting more larger drivers that cost much more, require more power, etc, compared to using something I already have. But I'm not quite sure if it's even feasible to get much lower with the JBL drivers, but in theory I would think 16 of them would be able to do it.
I was especially thinking they may have a chance at this, if they're fairly near field, such as built as a chest/cabinet behind the seating, and/or also as a coffee table, and at mid-points in the room where needed based on boundary based nulls.
Any thoughts on this?
Going the wrong way?
Very best,
I also wonder, maybe I'm going about the question incorrectly. Maybe I really should be asking how to add to my current system based on my current system with these drivers, if at all.
I currently have two moderately large subs (DIY) that are front and rear placed in the room, with no nulls. They're bass reflex tuned at 20hz.
Here's my listening position response after EQ and house curve applied in MiniDSP HD, with zero smoothing applied.
I'm primarily wondering if I can add anything to fill in the range under 19hz. I probably should have started with this question first. Since I have lots of these JBL drivers, I was thinking if I ganged a bunch of them up, it would add up to be a lot of surface area or cone surface and it would then minimize the need for excursion and minimize distortion and require overall less power to get higher SPL that is pretty clean. I was thinking with as many as 16 of these drivers, I might be able to fill in some of that sub-19hz area, if in sealed boxes. Rather than getting more larger drivers that cost much more, require more power, etc, compared to using something I already have. But I'm not quite sure if it's even feasible to get much lower with the JBL drivers, but in theory I would think 16 of them would be able to do it.
I was especially thinking they may have a chance at this, if they're fairly near field, such as built as a chest/cabinet behind the seating, and/or also as a coffee table, and at mid-points in the room where needed based on boundary based nulls.
Any thoughts on this?
Going the wrong way?
Very best,
Thanks; I have the drivers. This confirms what I was wondering in terms of 16x of them being enough to actually do some results under 20hz. Corners and/or mid-walls should be good. I'll have to keep playing with the numbers a bit, but thanks for taking the time to model in HornRESP like that!
Your model is just 4 drivers in the enclosure; not the results of 4 total enclosures of drivers right? Even that single enclosure has good numbers to me. So four of them would be the kind of overkill range that would be fun.
Very best,
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I use REW as you can see from my graphing above. I've played with the simulator, but in general I just use room harmonic order calcs to know where my nulls are to place subs for filling them and for avoiding sitting in a nasty null, hence my graph above with just 2 subs in the room. These new enclosures are targeting simply filling in below 20hz if I can. The pattern as you suggest will be based on those boundary influences.
Very best,
You're welcome!
Correct, 4 drivers in 1 enclosure. The 4 parallel speakers graph equals 4 enclosures in the 4 corners of a room. However, Geddes says you should put them on each wall. SPL vs flatter response.
Thanks again! I like those numbers too. I think I'm more interested in SPL. I don't think I need to flatten anything under 20hz in the room. If I do, I'll DSP flatten it from the highest peaks down to the frequency range I want to maintain. I also won't run these up to 100hz likely. My mains handle all that fine.
I wonder if they're fine standing up without a footer, or if the driver motion will cause them to rock or have motion. If they're not moving much maybe not. But if they're near xmax maybe they will rock a little. I can use a footer to solve that. Or I can lay them down on their sides, which is also fine.
Lastly... good lord how long does it take to get the `quote' button to appear.
Very best,
I wonder if they're fine standing up without a footer, or if the driver motion will cause them to rock or have motion. If they're not moving much maybe not. But if they're near xmax maybe they will rock a little. I can use a footer to solve that. Or I can lay them down on their sides, which is also fine.
Lastly... good lord how long does it take to get the `quote' button to appear.
Very best,
I really like force cancelling arrangement of woofers. I built a simple closed dual 12" sub and the box is really calm when compared to a single 12" one. It rattles furniture by the sound waves, not by excessive vibrations.