Using 2 10" woofers

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I purchased 4 - 10" RSS265HF-4 (partsexpress) woofers. I am going to build a cabinet with two 10" woofers per side. I will build them per the suggested enclosure in the website (1.68 cu/ft enclosure 17.25" 3" port f3 27hz for each woofer). I simulated it on winsd and it correlates to producing output down in the 30hz region. The cabinets will be used for music (not home theater).

I would like to operate the woofers up to 500hz. I was told they will work to 1khz. I will likely build them as discussed above but I have a question just out of curiosity. Would there be any benefit to operating one in a sealed enclosure and operating the other woofer in a ported enclosure crossed to the natural roll off of the sealed woofer (in a sealed enclosure spec state 51hz in .5-1cu/ft enclosure). My guess is that it causes more complication than help. I will be using an electronic crossover.

Just curious and thanks for any input
Regards,
gwho
 
Thank you for the help. My first goal was to make a musical bass module that would go down to 30hz or below (but with a slim form factor). I assume sub 30hz is subwoofer range (at least for these speakers). My goal is to try different configurations (mid/tweet) with this module as a learning exercise. I guess the 500hz is probably pressing the issue. I will look into a push push configuration but do not know anything about it. Will it do the 30hz or below like the ported version?

Regards,
gwho
 
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Push-push typically puts 1 woofer on each of oposite sides and tightly coupling them Acoustically in phase, mechanically out of phase.

An over the top example:

pushpushPR2.gif


In practise a stiff box and direct magnet to magnet coupling does most of the job. Her the inside of one of our push-push SDX10 woofers (built w 15mm BB):



dave
 
Thank you for the picture of the push push. So the woofer magnets are spaced about two inches from each other (do you want it as close as possible?). Are the woofers wired in parallel or are they wired opposite (so one speaker moves out while the other speaker moves in). Would I use the same speaker volume 1.68 cu/ft (x2) and the same port size
(3" x 17.25" (x2)).

Regards,
Gary
 
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Small spacing makes it easier to get really good coupling, but stiff is the important factor.

I have one design (pipe & drivers on hand), that spaces the woofers at the ends of 12” PVC tubes a bit less than a metre long.

The one pictured is fairly close to a square prism about wat high (i compromised on the short version). This means that the sides & baffle are fairly narrow and it allows for a brace in the shape of a plus sign to make panel spans less than 6” or so. The 15mm was choosen as a test of how well 15mm BB would do. At riduculous keveks i can excite the top, a chunk of corian or granite contrained layer on the top would fix that (and make them much more drink proof).

dave
 
Planet 10,

Thank you for information on the push push design. I will see if I can find more info on them. I did have the question about the design in my previous response. Do I just wire the woofers in parallel, use the same box volume as the ported design, and use the same ports?

Regards,
gwho
 
Yes, that is the quandry. I am making the assumption that however you do it you need to leave the vent open on back of the magnet where air can flow. I am going to explore this (still reading on it) but will likely use something like what Planet 10 proposed (which is a great idea) should I go this route. Let me know if there are any threads showing pictures of how they built this type of subwoofer for ideas.

Much appreciated Planet 10 for the idea.

Regards,
gwho
 
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Sounds simple in theory, when it comes to doing it in practice not so easy, the first picture you posted shows it's not so straight forward. How do you do it?

It takes a bit of work to get the magnet to just press up against the magnet, but it is not all that hard, just a bit tedious. Chris built many boxes simialr in concept to these, and every miniOnken (at least 100s) built has the same need for a close fit of the driver brace.

dave
 
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….you do it you need to leave the vent open on back of the magnet where air can flow...

I am not a huge fan of vented polepieces but in the SDX10 pictured and in our SDX7 builds we avoided covering them over. The brace should be just off-centre (to divide the subpanels on the back such that they do not have the same width so that they do not have the same potential resonant frequency.

Much appreciated Planet 10 for the idea.

Not mine originally. 1st was exposed to the trick by Jim Gawne, and then later seen in some KEF references, at least one NAIM speaker, and a growing number of others including a variation used by Martin Logan and Paradigm (?) in some of their subs.

One gets sonic benefits from much less movement of the driver basket due to reactive forces allowing for accurate reproduction of the small pieces of information (improved DDR) and cost benefits due to less cost to build he box and in the case of commercial products, the cost of robust shipping boxes and a reduction in shipping cost because the boxes are lighter.

With our push-push SDX10 build, one could lift the box with a couple fingers, with the drivers it became close to a 2-person (or one strong one) lift. If we had built it out of 3/4” MDF instead of 15mm BB the box would have weighed as much as the drivers, so for the DIYer, your back will tahnk you.

dave
 
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