I decided to get this sub for my car. (the UM18-22)
Previously I owned a Kicker 15" CompVX (the older one with ~20hz fs) in a kicker spec ported box. This one was in my car and I was quite impressed with the low frequency response (partially due to cabin gain) for music (the 40-30hz range).
Since then I built a large ported box for a infinity 1260w 12" sub (25hz fs) (with a SPA-250 for power). The box and ports were modeled to be tuned to ~25 hz giving an f3 around there. Personally I am not too impressed with the low vs mid bass relationship of this build (as measured by my ears). The sub needs about a 6db boost via a low shelf filter centered around 58hz (so starting to curve up around 100hz and starting to level out around 30 hz) to make my music live up to my current standards, low bass heavy. Now im sure some of this is due to cabin gain relationships. The car with the compVX was a small car and the 1260w is in my apartment. And some is due to the surface area being lower. And some is due to the sub being lighter, having a higher fs, a lower vas ect... ect
But when thinking about it i cant help but factor in the interference from the port and woofer being out of phase in output. Although they are likely not 180 degrees from eachother, I've been thinking about doing a sealed build ever since completing the 1260w.
Now I see this UM18-22 for only $250 that can get an f3 of ~27hz with a 4ft3 enclosure. All the base specs check out. Maybe a little lower efficiency for the high frequencies but that's the trade off. Good group delay. Good fudamentals like linear excursion in and out.
It just seems like nothing in the price range or even double it offers all these things.
Id like any advice anyone has for this build or if you know of a sub that competes with it for un equed f3 below 30hz in a sealed box please list that here.
I have 4 pounds of polyfill because the box is listed at 4ft3 MINUS the bracing and driver. There is no plate amp going in it just some binding posts on the outside to hook up to the car amp. I have no mic so a cheap one that is good would be awesome if you know where to get one. Otherwise Im just going to listen to it sealed with 2 3 and 4 pounds of fill and decide what sounds best.
Also what are your thoughts about port/speaker cancellation?
image of 1260w
Previously I owned a Kicker 15" CompVX (the older one with ~20hz fs) in a kicker spec ported box. This one was in my car and I was quite impressed with the low frequency response (partially due to cabin gain) for music (the 40-30hz range).
Since then I built a large ported box for a infinity 1260w 12" sub (25hz fs) (with a SPA-250 for power). The box and ports were modeled to be tuned to ~25 hz giving an f3 around there. Personally I am not too impressed with the low vs mid bass relationship of this build (as measured by my ears). The sub needs about a 6db boost via a low shelf filter centered around 58hz (so starting to curve up around 100hz and starting to level out around 30 hz) to make my music live up to my current standards, low bass heavy. Now im sure some of this is due to cabin gain relationships. The car with the compVX was a small car and the 1260w is in my apartment. And some is due to the surface area being lower. And some is due to the sub being lighter, having a higher fs, a lower vas ect... ect
But when thinking about it i cant help but factor in the interference from the port and woofer being out of phase in output. Although they are likely not 180 degrees from eachother, I've been thinking about doing a sealed build ever since completing the 1260w.
Now I see this UM18-22 for only $250 that can get an f3 of ~27hz with a 4ft3 enclosure. All the base specs check out. Maybe a little lower efficiency for the high frequencies but that's the trade off. Good group delay. Good fudamentals like linear excursion in and out.
It just seems like nothing in the price range or even double it offers all these things.
Id like any advice anyone has for this build or if you know of a sub that competes with it for un equed f3 below 30hz in a sealed box please list that here.
I have 4 pounds of polyfill because the box is listed at 4ft3 MINUS the bracing and driver. There is no plate amp going in it just some binding posts on the outside to hook up to the car amp. I have no mic so a cheap one that is good would be awesome if you know where to get one. Otherwise Im just going to listen to it sealed with 2 3 and 4 pounds of fill and decide what sounds best.
Also what are your thoughts about port/speaker cancellation?
image of 1260w
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Also here is a picture of the 1260w
An externally hosted image should be here but it was not working when we last tested it.
Hi OpenICG,
My verdict is:😱 A flawed Box design. Your concerns of any Port/Speaker cancellation is IMO irrelevant so is the thoughts of Group-Delay issues.
The worst you can do is to make a Cubical Box with an undersized Port system.
b 🙂
Attachments
So it is about particle velocity from the vents?
And I'm not sure I understand why the square box is bad but I would like to.
The Dimensions are ~49 by 43 by 45 cm. The ports are 2" diameter exactly so 5.08 cm and ~25 cm long. it is made out of 3/4" mdf so take off 3.81 cm for internal sides. Its about 68-69 liters with the driver and amp and ports taken into account.
And I'm not sure I understand why the square box is bad but I would like to.
The Dimensions are ~49 by 43 by 45 cm. The ports are 2" diameter exactly so 5.08 cm and ~25 cm long. it is made out of 3/4" mdf so take off 3.81 cm for internal sides. Its about 68-69 liters with the driver and amp and ports taken into account.
ok its bad because the dimensional resonances are the same. I think this box is just barely in the safe zone considering ~15% difference in internal dimensions
Yeah, a pair of 2" ports won't have enough area for a long-throw 12" driver. I'd be looking at a pair of 3" ports, minimum, possibly 3x 3", or 2x 4".
When the ports start chuffing, IIRC the performance drops below that of a sealed box.
Chris
When the ports start chuffing, IIRC the performance drops below that of a sealed box.
Chris
I guess either way it doesn't matter as the the frequency response is more of an issue at the lower levels that I can listen to it in my apartment without ******* off the neighbors. So its obviously not limited by port size.
It's not a 12" driver. It's an 18" driver. At least I think he is talking about a box for the UM18-22. Hard to tell.
That 18 needs at least one 6" port, to not suffer port compression at even medium output levels. But he listens in an apartment, so maybe he never reaches that SPL... or isn't bothered by chuffing and compression?
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The picture on the previous page is a 12" driver, which the OP has decided is inadequate.
Chris
The UM18-22 will be for my car in the sealed pre cut box sold by parts express. the box will have less than 4 cubic feet after the bracing and sub so Im going to add between 2 and 4 lbs of polyfill. Is there any way to test it that is better than listening to test frequencies to tune it? Unfortunately I do not have a tester or $100 to drop on one.
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