Can somebody with design software help out with a sub design?

[fvoelling]

Hi,

I may have a spare 10" car sub driver from JL Audio (10W7) that I'd like to use to build a home sub for my son's apartment, probably powered by a 300-500W plate amp (Dayton or Bash from PE). These are the parameters:

Free Air Resonance (Fs): 30.6 Hz
Electrical “Q” (Qes): 0.578
Mechanical “Q” (Qms): 7.647
Total Speaker “Q” (Qts): 0.537
Equivalent Compliance (Vas): 1.28 cu. ft. / 36.1 liters
One-Way, Linear Excursion (Xmax)*: 0.9 in. / 23 mm
Reference Efficiency (no): 0.171%
Efficiency (1W/1m)**: 84.3 dB SPL
Effective Piston Area (Sd): 59.8 sq. in. / 0.0386 sq. m.
DC Resistance (Re): 2.75 ohm
Nominal Impedance (Znom): 3 ohm
Thermal Power Handling (Pt): 750W
Driver Displacement: 0.09 cu. ft. / 2.5 liters
Net Weight: 30 lbs. / 13.6 kg

If I were to build a stand-alone sub, I'd probably go no bigger than 15x15x15. What kind of low frequency extension can I expect with either a sealed or a ported design in such a box?

My other option is to build him a coffee table sub, probably about 30x30x12 (with 3-5" legs), which is roughly 6cft. This could be a ported design with the sub downfiring into the floor (which would be better, carpet or hardwoood?). How much better low frequency extension would that give me?

Or should I just buy him a 10" Dayton HT sub for $230 and sell the JL Audio?

Thanks,
Frank

[BOBinGA]

Try it yourself. LinearTeam has an online calculator for the box size and another app to calculate vents after you run the box size. They are easy to use. Once you run the simple online calculator, download WinISD Pro from their site and give it a try. But the online caluclators should get you close enough.

http://www.linearteam.dk/default.aspx?pageid=isdonline

-Bob

[ThomasW]

Hi Frank,

The JL 10W7 is a much better driver than the one in the PE HT sub. So yes use it.

Not much sense trying to build a ported 15" cube it just won't work.

If you want to invest in a high excursion PR you could keep the box size relatively small and have higher output at Fb. But the driver would need protection from unloading trying to play frequencies below Fb. This would in essence be something like a Carver/Sunfire cube sub.

To do the PR sub you'd need to buy one of these. This would necessitate something larger than a 15" cube just to house all the parts.

[Rick Craig]

The parameters are best suited to a small sealed box with active equalization. The O Audio 500-watt amp is one you should consider.

[fvoelling]

Thanks, guys, all good suggestions. That 10W7 didn't work out - I was going to buy it as part of a package deal along with some car amps, but it's got a huge hole in the cone. Like they say, if it sounds too good to be true, ...

Well, first things first, I gotto finish my other son's car stereo project before I build anything else. We don't have a section here for help with car audio, do we? I'm still in sticker shock from what they charge for semi-decent speakers.

[HareBrained]

Well, first things first, I gotto finish my other son's car stereo project before I build anything else. We don't have a section here for help with car audio, do we? I'm still in sticker shock from what they charge for semi-decent speakers.

If you're in need of a system, Elemental Design has some great components. They even have a package deal, right now for a limited time, where you get a 4-ch amp, separates, and a 10" sub for $300. I have their 5-ch (now discontinued) and 8" sub and love them. Everything they sell is a very good value. http://www.edesignaudio.com

If you have specific questions, there is diymobileaudio.com and eD's forum. Plus, there's a few of us who've done it more than once. I was a SQ judge for a while, wrote a few articles for Car Stereo Review, and even tried my hand at competing. You can send me a PM if needed.