johns350z

Im thinking of upgrading my 2 - 10" FI Q's to 1 - 15" FI SP4. I am designing my box and wanted to put it out there and get some feed back from people more experienced with ported boxes than I am. I am extremely happy with the outcome of my 10's but of course there is always room for more. Oh btw I am pushing them with 2 Crescendo BC 2000 at 1 ohm, nominal 4,700 watts.

The box I am thinking of will be 31" W x 15" H x 19 " L. I was told by FI to make my port width no smaller than 4 inches but that is practically impossible with this application. I want port up, sub up. So I was thinking of 2.75" port width, total port length 36". This gives me a net box of 3 cuft without speaker displacement and tuning of 32htz.

Feel free to add comments If you have experience that you dont mind sharing.

dkmesa350z

iTrader: (41)

In for updates.

If your FI Qs are D4, I will take one off your hands

I've considered putting a slotport 12" enclosure back there...but the 10 works just fine for me these days.

johns350z

D4? Are you refering to the ohms? FI doesnt make a dual 4, only dual 1 (.7) or 2 (1.4). Mine are dual 1 (.7) ohms.

dkmesa350z

iTrader: (41)

hmm forgot about that. Can a single D1 be wired to 2 ohms total resistance? If so, I'd still be interested if you sell them.

johns350z

Yes you can connect the sub in series, + of coil 1 to the - coil 2. Then you hook up the speaker wire from the amp to the - of 1 and + of 2. This gives you a 2 ohm load. Yes I do want to sell them, I want 500 shipped for both. They are fully upgraded with options. What amp are you planning to run these with? You can hook these at 1 ohm mono or 4 ohm mono together.

johns350z

http://www.caraudioclassifieds.org/f...ly-loaded.html

johns350z

How about an aero port? Rick at FI told me to use 1 - 6" aero port if i was having problems getting down to 32-35 htz. Can someone please explain to me what length I should use, where I can buy aero port cheap and do I need to use an elbow?

Thanks,

John

jbrueshaber

Man, you can purchase aero ports at www.parts-express.com. The longer and/or wider the port the lower your box will be tuned. However, watch out overdriving/clipping those Q's. They have crazy, good X-max for 10's, but overtime the lower tones will shorten the life of the subs. I had two Fi Q 10's previously, and I blew them both. My box was tuned around 30 hz, and I playing nothing but chopped and screwed music. LOL! Hope this helps.

johns350z

Thanks for the reply. I actually have a good understanding of how slot and aero ports work now. I did some research and learned how to achieve my required port area and desired box tuning frequency. Your comment of "The longer and/or wider the port the lower your box will be tuned" is a little off. The longer you make your port the lower the tuning but the wider you make it the higher the tuning will be. If you use a 6" port vs a 4" port your lengths with a 6" has to be substantially longer to achieve the same frequency.
Ive had my Qs for about 3 months now and Ive put them in three different boxes and the box they are in now is by far the best. I had to reinforce the slot port and double the baffle. I am pushing them pretty hard and they are taking it like champs. I clamped it a while back before i raised the gain up again and I got 3,800 watts going to them. So they are powerful little suckers. I am getting a good amount of flex in my car I just wanted to upgrade because I felt if I got more cone area I would have to push it less to get the same output.