Need some pro help -12" Fi Q enclosure w/pics and info -

[FullCircle 10+ year member]

Hey all,

Been a month or so since I first posted looking for some help. I got some good info from here and some other boards, and bought a sub for my is300. I ended up getting a new amp as well, as the one I had wasn't ideally suited to my woofer needs. In any event, I have been playing a bit and think I am at the point now where I can hone in on a final design, build and finish this phase of my system.

Here is the deal - have a Fi Q 12" (yea yea, I know, forum boner, but must say, I am very impressed at the value of the line and Scott is a great person to work with), in a ported box. Right now, it's a 1.75^3 net, with a 4" aeroport, 17" long tuned to about 32. My goal was to get a good output SQ setup, while taking up as little space as possible. I threw together this enclosure as a test, just to start getting an idea. What I ended up with was some bass, that is rather accurate, but not at the level I would have expected for this speaker running about 1100w to it.

I am running a line out from the stock amp via a mod to the board done by soldering in some RCA's to the PCB (thanks to the my.is forums). They run to a Memphis line driver. While I am sure it's not the flattest or ideal signal, it is not crossed-over for the channels I used. The line driver feeds the MC-1000D. (sidenote: I am dead set on retaining the stock HU, but will soon be adding a 3sixty.2, along with new comps and power (probably going with the SLC or Germs after hearing some SLC's recently, was amazed).

I have found that the output from the box when at the rear of the trunk, facing forward is really amazing. I want to achieve this sound, essentially, with the speaker facing the rear, all the way against the seat. Currently, there is about 6" from port to opposing wheel well - the port was placed in the side of the box. The box was made to slide right over the right wheel well, against the back seat. I do no have deadner yet, budget has been rough, but I am getting that in next week. Rattles are pretty limited as car is well-built, but deadner should help resonance.

Here are some pictures -

Shot of the trunk, you can see the ski pass

http://picasaweb.google.com/perryjones/CarStereo/photo#5035415125176630386

Shot of the box I have right now - it's a test jobber, so please take it easy on me. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

http://picasaweb.google.com/perryjones/CarStereo/photo#5035416920472960178

And here is a shot of the ski pass, from the front looking in. Here is when I had the box at the rear of the trunk, facing forward and it hit really nice, hard, and clean.

http://picasaweb.google.com/perryjones/CarStereo/photo#5035415550378392706

That all said - here are the questions -

1) Would I see a noticable increase in output and response flatness by going to a box that was approximately 2.25^3? (this is about the largest I am willing to go, I need space to carry things for my daughter, and my guitars - etc)

2) Would going to a 6" port make a large different in output? I would need to use at least one 90 to make the necessary length of about 30" at 2.25 to achieve desired tuning.

3) Could I use the ski-pass as a port? It would seem this may turn my trunk into some sort of bandpass, but I would think if I figured out the proper setup, this would be great to get the output I want. Please keep in mind I listen to mostly rock and reggae type music, with some hip-hop/rap once in a while.

Thanks for reading this, if you got this far. It's a long post, and I appreciate any help.

I can take more pics if needed. Keep in mind, this is just the beginning, so the wires and such will be re-ran and hidden in a false bottom. (though, the spare tire will be kept, as I commute through BFE to get to work).

-FC

Click to read more...

 

[mazdakid 5,000+ posts]

pics dont work for me

 

[Volenti 10+ year member]

Hey all,


3) Could I use the ski-pass as a port? It would seem this may turn my trunk into some sort of bandpass, but I would think if I figured out the proper setup, this would be great to get the output I want. Please keep in mind I listen to mostly rock and reggae type music, with some hip-hip once in a while.

-FC

In a setup like this I often use a bandpass enclosure with the port firing through the ski hole and use the box to seal off the boot space, it's better to design a BP to suit than to gamble on the boot volume+ski hole being the right tune, I don't have the specs for the Fi subs but a BP enclosure of around 2-2.5cuft should be do-able, post the specs for the sub and I or most likely 80inches can have a look at that option for you.

yea and the pics aren't working on my end either

 

[60ndown 10+ year member]

well built cars with trunk mounted subs are notorious for being hard to bass up front.

use the ski hatch somehow, bp ported who knows what will work best untill you try? might want to consider selling the fi and get a pair of good 8s and hang em off the rear shelf ib styleie?

 

[FullCircle 10+ year member]

Thanks for the replies so far guys. Another thing to keep in mind - I don't want to make any permanent changes to the car ala cutting holes in the rear deck, or rear-seat wall. It was late as hell last night, so forgot to mention a couple things.

One other issue I can think if is that the box needs to be removed pretty quickly without a lot of tools. This is probably the least of the difficulties to overcome, but figured it was worth mentioning.

Another option that may be worth trying would be to go sealed, speaker facing forward, into the pass hole. While a bit of the speaker would be blocked my the back seat, this might be better than the box facing backward? Obviously not the best solution, but perhaps a good comprimise? i wouldn't mind the extra space, that is for sure. .75-1 ft^3 would be easy to fit.

The box in the pic has a 'face' plate that is larger than the box, and is formed to allow level placement when taking into consideration the fuel hump, and is contoured over the wheel well. The idea was, if it sounded good, to carpet to match the stock color, maybe through a small graphic on it, and use the space to the left of the box for an amp and driver rack.

thanks again for the reads -

FC

Really, a bit more complicated than what I am used to seeing, so that is why I am here. =)

 

[Volenti 10+ year member]

Another option that may be worth trying would be to go sealed, speaker facing forward, into the pass hole. While a bit of the speaker would be blocked my the back seat, this might be better than the box facing backward? Obviously not the best solution, but perhaps a good comprimise? i wouldn't mind the extra space, that is for sure. .75-1 ft^3 would be easy to fit.

thanks again for the reads -

FC

Really, a bit more complicated than what I am used to seeing, so that is why I am here. =)

A sealed setup like this should sould pretty good, tight and accurate, part of the sub being obscured by the back seat won't matter, the important part in any front firing boot sub is to block off the boot from the cabin space.

 

[mlstrass 5,000+ posts]

Why not build a box to fire through the opening and place it all the way forward,s so you don't lose much trunk space? I have my 15's forward firing through the rear seat opening and like the SQ a lot. Might lose a little overall output, but I'm not worried. I covered the opening with speaker cloth so it's stealth.

 

[FullCircle 10+ year member]

Why not build a box to fire through the opening and place it all the way forward,s so you don't lose much trunk space? I have my 15's forward firing through the rear seat opening and like the SQ a lot. Might lose a little overall output, but I'm not worried. I covered the opening with speaker cloth so it's stealth.

Yea, I am thinking that is what I may try. Perhaps use a double baffle in the front, but with the sub mounted to the second baffle so the speaker sits almost flush to the face of the box.