# Cut port or install PR for SDX 10



## christmclean (Feb 13, 2012)

I purchased an occam audio SDX 10 downfiring sub about a month ago. The dimension are 12.5 x 14 x 16. The port length is 12 inches. I replaced the straight port with a flared precision port keeping the 12 inch length and had an issue with the amp not getting signal after reinstalling. Madisound was great and sent me a new keiga 5230 amp under warranty. The new amp has a plastic enclosure covering the amp internals making the width larger. Now the amp sticks out about a half inch out from the box where it hits the port.

Trying to decide if I should just cut the port down another inch so the amp would fit but then the space would only be less than an inch tolerance from the port flare to the amp, and the port would be 11 inches.

Or would it be possible to take out the port and put a 12 PR in the front of the box. It looks like the cutout would just fit but I dont know if the would work as I have not used any of the modeling programs before.

Any help on a solution would be appreciated.


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## Mike P. (Apr 6, 2007)

Welcome to the forums!

The cheapest solution would be to use an elbow with the flared port and make the overall length 13" long to maintain the same tuning frequency as the 12" straight port. The port intake needs 3" of clearance. A 3" PVC schedule 40 elbow is a couple of dollars.


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## christmclean (Feb 13, 2012)

Thank you, that is awesome. I like nice simple solutions. Off to home depot I go.


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## Mike P. (Apr 6, 2007)

To get the required port length take the measurement through the center of the tubes and the elbow.


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## christmclean (Feb 13, 2012)

I went to home depot and got an elbow. It just won't seem to work. There is just no room in the box for it. There is only 4 inches on each of the sides of the box and no room on the bottom where the driver is, and no room on the top where the port is mounted. I ended up just cutting off another 1.5 inches so I would have at least 1 inch of clearance to the amp. This should make my port length 9.5 inches. I kept the flared internal end but almost left a straight end just to try and get another half inch of port but figured the flare would be better to have on there. I am guessing my F3 is considerably higher than 26 which is what was published. Not much I can do about it with the small box and clearance to the amp.


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## Mike P. (Apr 6, 2007)

Too bad it didn't work out. Are you using this sub for music?


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## christmclean (Feb 13, 2012)

No I am using it for a TV system with a soundbar, so mostly movies. I thought that the SDX driver was good for playing up to 100hz to mate with the soundbar. Looks like I will be missing some of the low bass content, but a small box was wanted.


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## Mike P. (Apr 6, 2007)

The dimensions of the box you posted are external?


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## christmclean (Feb 13, 2012)

Yes. 3/4 inch plywood.


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## Mike P. (Apr 6, 2007)

Did the sub originally come with a Keiga 5230?


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## christmclean (Feb 13, 2012)

Yes. Madisound told me it was a model from 2009. They replaced it with the current model. The current model has a plastic covering on the back of the amp. I figured that this would help protect the electronics and when I remove the cover there are screw holes that would be where the driver hole is that would have to covered and there is no longer gasket tape as that is now on the plastic cover. It probably adds about half to one inch to the total depth of the amp. I think the straight tube at 12 inches must have been very close to the amp.


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## Mike P. (Apr 6, 2007)

Originally the sub was tuned to 38.5 hz, with the changes you made it's now 40.75 hz. That amp has 4 db of boost at 25 hz and a subsonic filter at 15 hz. If that's what they sent you then your sub will bottom out at 30 hz.


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## Mike P. (Apr 6, 2007)

Yellow is what you currently have, if you limit the power to 90 watts the driver stays at Xmax. Green is if you plug the port for a sealed system, with 175 watts the driver is at Xmax.


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## christmclean (Feb 13, 2012)

Thank you for putting this info together for me. What you have modeled and what Jeff Keyes over at Occam don't seem to match. Here is what he sent me in an email when I asked about the sub bottoming at 30hz with 90 watts.

"90 watts at 30 hz the cone moves 5mm, 300 watts at 30 hz the cone moves 9mm. The SDX10 has a 18.4 mm xmax one way. Even at 1000 watts it doesn’t bottom out at 30hz, it moves 16mm. Changing the port from 13” to 10” changes the port tuning by 4hz. In fact it would improve your power handling in exchange for a slightly higher F3."


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## christmclean (Feb 13, 2012)

With what Jeff Keyes sent me I figure I can test out the box with high power and I should hear the driver bottom out. It seems there are some different models of the sub as configured.

I also plan to download WINisd and try testing some configurations out myself.


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## christmclean (Feb 13, 2012)

I tested the sub before I went out of town. I think the sub sounds like it might be bottoming a little with the port open, but this might just be port chuffing. With the port sealed the sub does not sound like it bottoms at all but also does not sound like it has as much bottom end. I will post some info on some measurments I took with Radio Shack meter soon.


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## christmclean (Feb 13, 2012)

Well I am finally getting around to posting my findings with some testing. I used my analog radio shack meter and some test tones. I have a Speaker Company TSC-250 that is exactly the same size as the Occam SDX-10 sub but has a slot port. I have put some foam in the box and it has a low to mid price driver. The TSC sub gain was set to max to get the results shown here. The Occam sub was set about 2/3 so had a lot more volume that could have been gotten out of it. I also have a SVS PCI 20-39 plus with the 550 watt amp and the 12.3 driver. I ran the Occam with the port open and then put one of the port plugs that I had from the svs in for the sealed measurements. 

I was surprised that the TSC-250 did not drop off as fast at 40hz as the Occam ported did. It is also a much bigger difference to the SVS in the 20 hz range than I thought. A bit disapointed with the SDX-10 as it is configured in the sub box. It shows that the size of the box does make a difference. I think if had went with one of the 18inch cubes quartet 10 kits it would have been a lot closer to to the SVS. I might just have to use the driver and put together one of these kits to get much better Home Theater perfomance with the robust SDX-10 driver.


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