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"I think it's the opposite. hO being better for music while the hf is better for movies because it is able to play lower ."


mpray, that is bad information.
 

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the "ho" is more of a car spec sub, while the "hf" if more of a home drive.


i'm not going into it here...theoretical 2 pi response attached.


4 cubes each.


best,
 

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Discussion Starter #23
Ok, so I definitely want the HF then. I finally got it to work after putting it in compatibility mode and doing the backspace/tab thing. So the volume it says is 5.555 cu ft. So I should aim for that? Would 5 work? A bigger box would have a shallower roll-off and smaller Q; what Q should I aim for? An 11+ cu ft internal dimension box would be pretty big.


And with the amp, is it ok to run without a highpass/subsonic filter? Or what should I use?


What kind of output could I expect with 4 of these? The graph peaks at 87dB??
 

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Look into many of the dual opposed designs around here. many of the members, including me, made dual opposed cabnets back when the mfw's where available. but the dvc Daytons are pretty much the same driver spec wise. you would have more than enough output to get into trouble with 2 cabs with dual 15 inch woofers in each...
 

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Discussion Starter #25
Well that opens another possibility. The problem is that I don't have much floor space and a dual opposed sub would take up a significant amount of floor.


What box designs choices do I have though, without regard to floorspace under 12 cubic feet? I searched a bit but couldn't find any info about why you would use a dual opposed sub.


So what are the advantages/disadvantages of the different possible designs? Sound quality, output, frequency response?
 

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2 opposing drivers basically make the cab not vibrate at all. When I touch mine I can barely tell it's on. I have two dual opposed and when I turn on the 2nd I get an extra 5-6db at the listening position. My boxes are only 5cf each and I can run them with 1 amp.
 

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Discussion Starter #27
Ok, so is the main thing that they don't vibrate? If you turn any set of 2 other subs on you should gain that much, correct? It's not something special to the design? And either way I'd be powering these all with one amp.


I don't know how you'd determine the required volume of the box, but if I could cut that in half with a dual-opposed design and get similar SQ, SPL, and FR that is very tempting actually. I found a dual-opposed tower build too.
 

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Quote:
Originally Posted by bradthebold88 /forum/post/0


Ok, so I definitely want the HF then. I finally got it to work after putting it in compatibility mode and doing the backspace/tab thing. So the volume it says is 5.555 cu ft. So I should aim for that? Would 5 work? A bigger box would have a shallower roll-off and smaller Q; what Q should I aim for? An 11+ cu ft internal dimension box would be pretty big.


And with the amp, is it ok to run without a highpass/subsonic filter? Or what should I use?


What kind of output could I expect with 4 of these? The graph peaks at 87dB??

You should aim for a .7 q but it is okay to go a little higher. You will need Something to eq them as well like minidsp which seems to be the crowd favorite or the Behringer dsp1124.


You can graph 4 just add the appropriate volume and put 4 drivers in. With sealed you don't always need a highpass filter because the box kinda limits it. If your box is huge and a lot of power you may need it. Look at the excursion graph from the drop down menu and from what I have heard and done myself I keep it to 10% above Xmax which should be a red line in winisd. 5 cf should work just make sure you allow the extra volume for the drivers, bracing and a double baffle.
 

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Quote:
Originally Posted by bradthebold88 /forum/post/0


Ok, so is the main thing that they don't vibrate? If you turn any set of 2 other subs on you should gain that much, correct? It's not something special to the design? And either way I'd be powering these all with one amp.


I don't know how you'd determine the required volume of the box, but if I could cut that in half with a dual-opposed design and get similar SQ, SPL, and FR that is very tempting actually. I found a dual-opposed tower build too.

You can't cut the volume in half just because it's a dual opposed. You still need the same internal volume whether you use 4 single or two dual opposed. Another positive to dual opposed is you only have to build two boxes which is nice.
 

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Discussion Starter #30
Ok, I was just wondering about volume because you said you only have 5 cf boxes. So I would need 10-11 cf for a dual-opposed design? I had planned on just building 2 divided boxes, so it's pretty much two separated on the same side, or two on opposite sides in a shared box. Is there a performance difference?


For an EQ, I have Audyssey MultiEQ XT in my receiver that has a 5-band (non-frequency adjustable) sub EQ, would that work?


In winisd, with a 5.5cf box, it says the sub will exceed x-max at 36Hz with 500W going to it. At that size, I would have to limit the power to 200W to reach xmax at 18Hz. Or I would have to drop the box size to 2.4cf at 500W to reach xmax at 30Hz. That can't be right. (Maybe the entered parameter is for one-way xmax and it is plotting the full 2-way xmax?)


Thanks for the patience, there really is a lot of new information in DIY.
 

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Discussion Starter #31
It looks like, all things being equal, the advantages to dual opposed designs are no vibrations, otherwise they should sound the same? How far would the driver have to be away from the wall with this design? And does it matter if a driver faces the couch or out towards the kitchen; would there be a difference?


Any other high SQ subs that could have smaller box requirements around the same price? These boxes are going to be big... around 21" W x42" L x 26" H for a dual opposed one, >150lbs.
 

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Quote:
Originally Posted by bradthebold88 /forum/post/0


It looks like, all things being equal, the advantages to dual opposed designs are no vibrations, otherwise they should sound the same? How far would the driver have to be away from the wall with this design? And does it matter if a driver faces the couch or out towards the kitchen; would there be a difference?


Any other high SQ subs that could have smaller box requirements around the same price? These boxes are going to be big... around 21" W x42" L x 26" H for a dual opposed one, >150lbs.

With the Dayton DVC 15" which are currently on sale...3cf per driver so 6cf dual opposed is fine. Run on an ep2500/4000 is a proven design that many including myself have done. Just look up mfw dual opposed build threads and you will find a few to give you some ideas. I keep mine about a foot away from the wall but I have seen people be as close as 4" away from the wall. You can do side firing dual opposed or front to back. It's all a matter of preference.
 

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Quote:
Originally Posted by bradthebold88 /forum/post/20978253


It looks like, all things being equal, the advantages to dual opposed designs are no vibrations

The advantage to dual opposed is that the box won't dance at high volumes, as there are equal opposing pressure waves emanating from the cab, cancelling out any tendency for the box to move. It has no bearing on the vibration of the cabinet panels, because internal pressure isn't cancelled. That would only happen if the drivers were wired with reverse polarity, and that would cancel out the sound output as well.
 

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Discussion Starter #34
Ok, for a dual opposed HF box, I calculated it should be around 200lbs (1 1/2 sheets of MDF, 60lb drivers), and a DVC box would be around 130lbs (1 sheet MDF, 38lb drivers). 200lbs would be a giant pain to carry up and down stairs when I move (not that 130lbs would be fun either). So if I went with the HF's, they would have to be in individual boxes, or take the drivers out of the dual opposed box when I move it to save 60lbs.


How much power can the DVC's take? Parts express says 350W per coil RMS, 600W total. Dayton's website just says 350W RMS, 600W max. So how much can the whole sub take? If it's only 350W/sub, then 1200W/channel from the EP2500 seems like way overkill.


How would the DVC's sound compared to the HF's sound quality wise? Assuming I used winisd right, running 2000W to 4 HF's and 1400W to 4 DVC's, the HF's have 2-2.5 db more output and -3db is 6Hz lower. Seems pretty significant. The HF's look like higher quality subs too, it would be nice if they didn't need such a big box.
 

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Discussion Starter #36
Well that's disappointing, I thought the EP2500 had truer numbers. Running 1600W to the HF's, there's a 2.5db difference that's starts to taper and is the same at 50Hz, still 6Hz lower -3db though. The HF is 116.7dB at 20Hz and the DVC is 114.4dB.


How's sound quality compare? Otherwise it's smaller size of the DVC vs the higher output and lower Hz of the HF.
 

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Discussion Starter #37
"We have used this amp for about 2 years on mono channel 1, channel 2 works but it's scratchy from not being used."


From an ebay EP2500 auction. Is there anything wrong with this? Being scratchy from not using it sounds strange.


I'll probably just go with the DVC for size. What would be the next step up in quality for $250 or less with similar size requirements? If there's something better, I could just start with one box.
 

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Discussion Starter #38
The auction for that amp ends in a couple hours, is it ok?
 

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Considering you have no idea what scratchy means I would say no...you can go to guitar center and they will match pricing on an ep4000 from any online authorized dealer. I usually get them for $300 there with the price match.
 

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I personally wouldn't bid on it. I would hate to purchase it and have to have it serviced shortly after making it more expensive than a new one.
 
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