WinISD guru - Want to confirm something

[naiku]

I have a single 10" MB Quart PWD254 in a small sealed enclosure of about 0.6cf, however when I plug the values for the sub into WinISD it is telling me it would work much better in a enclosure almost 3 times the size.

I am not sure if I am either running my sub in an enclosure too small for it, or if I did something wrong with WinISD. Everything I have read (which is not much) on these says they do fine in a small enclosure. I get plenty of output from it, but want to make sure it is working as well as it can be.

The specs on it are:
Re: 1.6 ohms
Freq response: 21-300 Hz
Fs: 28 Hz
SPL: 93 dB 2.83V/1m
Vas: 2.15 cu. ft.
Qms: 6.6
Qes: .52
Qts: .48
Xmax: 9.5 mm
Power handling: 300 watts RMS

I currently have it on the sub channel of a PDX V9, gains at about 50%. I have a spare sitting on the shelf, which I am tempted to run. But, if I can get the single sub working optimally may just stick with a single.

Thanks.

[chithead]

I vote the pair, in 1.25 sealed, just because

Truthfully though, WinISD has done the same thing for me before. A subwoofer that the manufacturer recommends in smaller enclosures, it suggested a much larger enclosure.

I'm thinking manufacturer's use a generalization with their recommendation, most likely based on an approximate balance of output, low-end extension, and power handling. Kind of a middle ground of sorts that the average listener can use to ensure moderate results, with good reliability.

[naiku]

Now are you saying 1.25 sealed for both? or 1.25 sealed each, so 2.5 for the pair?

Honestly, I am tempted to run the pair. It would mean I have to move the one from it's current location and then moving my amplifiers, but if I move the sub it means I don't have to build a new trunk floor and sides.

[chithead]

I would say 1.25-1.50 for the pair, or 0.6-0.75 each.

[dejo]

I would guess that either the manufacturer has stated a smaller enclosure to sell units. or possibly that winisd is using a different alignment than what the manufacturer is using. Not positive but think winisd defaults to .707 alignment

[chithead]

This ^^^ Although I know those particular MB Quart subs do work very well in smaller enclosures.

[naiku]

I would say 1.25-1.50 for the pair, or 0.6-0.75 each.

Thought so, figured I would check to be sure though. I think I will aim for 0.75 each before taking into account the space the subs will take up, so likely end up somewhere around 0.7. Thanks.

[subwoofery]

I vote the pair, in 1.25 sealed, just because

Truthfully though, WinISD has done the same thing for me before. A subwoofer that the manufacturer recommends in smaller enclosures, it suggested a much larger enclosure.

I'm thinking manufacturer's use a generalization with their recommendation, most likely based on an approximate balance of output, low-end extension, and power handling. Kind of a middle ground of sorts that the average listener can use to ensure moderate results, with good reliability.

Really good reply there. Car manufacturer's know that the average listenner doesn't much clue about gain settings or amp power matching...
Sending distortion or too much power usually is OK with the manufacturer's suggestion - which is on the small side

Reliability (controlling heat and over-excursion) is a priority in order to not lose too much money.

Also suggesting small enclosure pleases customers more and more - just look at Class D amps.

Use WinISD, it's a good program to know which enclosure is better suited for your subwoofer. A JL amp performs much better in an enclosure 25% bigger than the manufacturer's recommendation...

Just sayin'

Kelvin

[chad]

Along the lines with controlling excursion i think they also assume a standard amount of cabin gain.. Now, of course a large SUV or a school bus may require a larger enclosure but still.

I always go with a Win ISD spec if I can, they shoot for a Q of .7 if I need less low end I'll just turn it down. I hate power compression.

[cajunner]

since you admit to having plenty of output, and only wonder if you're getting all the performance you should be, why not take the opportunity to test your sub?

it might already be tuned successfully with your current box and if only a small gain could be achieved by the effort of replacing the current enclosure with a larger one, it wouldn't really be worth it in time and expense.

adding a second sub, and using an enclosure that allows for maximized output, is only preferable if your listening profile requires it, otherwise sticking with the smaller box of a single sub may be a better use of limited space in the vehicle.

something I've come to accept is how the .75 cubes per 10" sub, guideline is more or less, ideal in calculating box volumes. I believe most manufacturers try to produce the ideal output profile at .75 cubes which is a standard box size for many of the pre-fab box builders as well... I know WinISD can spit out corrected numbers that attempt to bring ideal box volumes to where .7 Qtc is produced but most people prefer the less clinical bump of say, .9 or so...

a little rise in output in frequencies that most music resides, from your smaller box means you're getting a bit of a free lunch, already.

it would be more better, for you to find out if at present, the bass drops off too much for your given music tastes. Realistically, going from .6 to .75 cubes, shouldn't do a whole heck of a lot in terms of FR in a sealed config.

If playing test tones and your sub goes quiet in-car, at say, 30 hz and under, how much do you need those really low tones, and how much effort is involved in the larger, perhaps dual sub box?

one thing that is certain is with twice the coils, a dual sub box is likely to absorb long-term play times better than the single, for longevity purposes.

that would be one overriding factor in my decision-making process, since you already own the second sub and you don't seem to mind the wasted space, and also have the watts available from your amp.