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Discussion Starter · #1 ·
Well I recently made my plunge into the car audio world, and wow is it easy to get somewhat loud and clean. As a "staple" subwoofer, I threw a Kicker Comp c10" sub in my old ht 10" box...I'd say about 1.5 cubes tuned to somewhere around 35-40hz, and it actually it pretty decent for a $50 sub. Frankly I'm shocked...feeding it ~500w I believe when its rated for 150w and its taking it like a champ. No distortion yet lol.

Anyways, I no longer have access to WinISD at the moment.
I'm debating between getting a Fi Q15, or two RE Audio Se-X 12's. I have 1000w on hand, if I went with the 15, it'd get 1000w, or each 12 would get about 500w. Could someone model up a comparison of the two for me? I would like to keep the box size down to about 3 cubes...maybe 3.5 at a max. A tuning of 29-32hz would be nice, but if it's not realistic, then please model the next best option for that size.

Here are the specs for the Dual 4ohm RE Se-X 12's:

Electrical Q Value -Qes: 0.49
Mechanical Q Value -Qms: 4.5
Total Speaker Q Value -Qts: 0.44
Free Air Resonance -Fs: 25.1 Hz
Equivalent Compliance -Vas: 72.9 liters
One-Way, Linear Excursion -Xmax: 18 mm
Efficiency -SPL 1W/1m: 86.1 dB SPL
Effective Piston Area -Sd: 480 cm^2
DC Resistance -Re: 2.8 ohm
Nominal Impedance -Znom: Dual 2 or 4 ohm
Thermal Power Handling -Pe: 600 W
Force Factor -Bl: 17.7

Here are the Fi Q15 specs:

DUAL 1 | DUAL 2

Fs: 32.4 Hz | 32.1 Hz
Re: 0.7 Ohms/coil | 1.4 Ohms/coil
Qms: 8.52 | 8.61
Qes: .43 | .44
Qts: .41 | .42
Mms: 293g | 299g
Cms: 0.82mm/N | 0.82mm/N
Sd: 810cm^2 | 810cm^2
Vas: 75.6 l | 75.6 l
Spl: 89.6dB 1W/1m | 89.4dB 1W/1m
Bl: 13.9 N/A | 19.65 N/A
Xmax: 28mm
Rms: 1500W
Sealed box: 2-2.6 cuft
Ported box: 2.8-4 cuft @ 28-33Hz
Sub OD: 15.625”
Cut ID: 14.125”
Mounting depth: 8.500”
Displacement: 0.19cuft

Also, I am a little confused with the wiring that would be needed. I'm using an Audioque 1200d, and in the manual it shows running a wire from both positives on the amp, to the positive on the sub, and both negatives on the amp to the negative on the sub. Supposedly that is "4 ~ 1ohms". To wire the two 12's down to one ohm, I'd need two D4's, and wire them like this, right?
 

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Before we go any further, do you have any eq on hand, like Audyssey etc. A single Q15 with eq for example will hit 30hz sealed no probs at all, porting it will simply allow more output to tuning but with less extension.
 

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Discussion Starter · #3 ·
Before we go any further, do you have any eq on hand, like Audyssey etc. A single Q15 with eq for example will hit 30hz sealed no probs at all, porting it will simply allow more output to tuning but with less extension.
At the moment, I do not. I wasn't really sure what kind of eq device I should get for a car, what would you recommend?
I would honestly prefer sealed, just for the ease of build and sound quality but I like the extra output possible with ported.
 

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Just my two cents. If your looking for a decent eq for car audio audio control make a few nice ones for a decent price. Although in all of the years that I've done car audio I have just used a decent external xover and applied a little boost through it. If you are interested I have two different xovers I would be willing to sell. And audio control 4xs and a kicker 3xi I believe are the two models.
 

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Discussion Starter · #5 ·
Just my two cents. If your looking for a decent eq for car audio audio control make a few nice ones for a decent price. Although in all of the years that I've done car audio I have just used a decent external xover and applied a little boost through it. If you are interested I have two different xovers I would be willing to sell. And audio control 4xs and a kicker 3xi I believe are the two models.
Okay, I'll check them out.

Will either of these do what would be needed for me?
http://www.kicker.com/equalizers
 

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Reading in what you have said. If your looking to just help your sub you can use an active xover to apply a LPF and also apply a bit of low end boost. Using a sealed sub in a car you don't really have a need to use a HPF. Just a thought.
 

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Discussion Starter · #10 · (Edited)
http://www.fortunecity.com/skyscraper/black/438/sigproc.html

I also have this for sale. Scroll down to the 3xi portion of the page.

What is the reason you want an eq over an active crossover ?
I never really said I wanted an EQ instead of an active crossover, I was asked if I had an EQ of some sort that I could use, so I thought I should buy an EQ device. I honestly don't see how I would use an active xover as an eq.

Reading in what you have said. If your looking to just help your sub you can use an active xover to apply a LPF and also apply a bit of low end boost. Using a sealed sub in a car you don't really have a need to use a HPF. Just a thought.
I can already apply a LPF through my headunit, and through the sub amp itself, so that's not an issue. The amp has a built in boost, I don't remember what the specs of that are, but variable db at 45hz sounds very familiar.

Should I go with the two 12's sealed, or the 15 sealed? How much output are we loosing here by going sealed?
 

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Alright let back up a bit then lol. I would personally use the two 12's. I just took a single 15 out of my car and it was never enough. As far as using your LPF on your head unit and amp I have never been a huge fan of using either of these options on amps and head units. I believe that using an external xover add a bit cleaner of sound I can't 100% explain it but it seems as most of the times with head units the slope is a bit and you can't fine tune your frequency like you can on a sand alone unit. As far as the amps onboard xover I have found that they am be hit or miss. This is purely an opinion. Both will cut freq to the sub so the choice is yours. That said I would not turn both of them on and personally if I was going to use either I would use the one one the amp.

Unfortunately I don't have access to winisd either so I can not model them for you but if I had to make a decision bases on experience I would go with the two twelves.

Good luck
 

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Discussion Starter · #12 · (Edited)
Alright let back up a bit then lol. I would personally use the two 12's. I just took a single 15 out of my car and it was never enough. As far as using your LPF on your head unit and amp I have never been a huge fan of using either of these options on amps and head units. I believe that using an external xover add a bit cleaner of sound I can't 100% explain it but it seems as most of the times with head units the slope is a bit and you can't fine tune your frequency like you can on a sand alone unit. As far as the amps onboard xover I have found that they am be hit or miss. This is purely an opinion. Both will cut freq to the sub so the choice is yours. That said I would not turn both of them on and personally if I was going to use either I would use the one one the amp.

Unfortunately I don't have access to winisd either so I can not model them for you but if I had to make a decision bases on experience I would go with the two twelves.

Good luck
Would you recommend me using an active crossover, or an EQ device?

I was able to get my old windows computer up and running again and modeled some stuff. I'm thinking the two 12's ported would be money, but people keep recommending sealed....I don't know what to do.

Let me know what I should change!

I've uploaded the driver files and project files also. One thing to note with the RE 12 file...you have to manually change the SPL and Vas before modeling the driver, meaning once the driver is opened, click the "parameters" option and change it there.
 

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Ported or sealed is 100% in my eyes a personal taste and the sound quality will
Vary with the different types of music you listen to. If your worried about low end response I wouldn't. In car audio the amount of cabin gain on the low end you receive is pretty wild. I personally am a sealed sound kind of guy. That being said no one way is right or wrong it's just personal preference. I think unless your looking to do db drag or spl competitions I would go sealed. As far as the eq or active xover if it were me I would use an active xover. The price you will pay for an eq worth while isn't really worth it unless you plan on doing some sort of sq competition. If you want to do something along the lines of best of both worlds your could use something like the audio control dqx or dqs. Both are an xover and a small eq in one but you will pay a premium for them. If not the audio control 2 or 6 xs will do very well. That would just mean you would turn off both the xovers on your amp and head unit and let them do their thing an let the xover do it's job. In my eyes you use the product for what it's made for. You don't stir soup with a knife.
 

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Discussion Starter · #16 ·
The drivers in question should be put in whatever box size the manufacturer recommends.
Fi recommends 3-4 cubes at 28-33hz, and RE recommends 2 cubes at 33hz. So I figured 3.5 for each was about the best for them since I was modeling two 12's.
I'm going with the 15. I know a friend that really likes his, and says it'll be plenty for that car. It'll be easier to fit an aero port in that box design also, among a few other reasons.
He was recommending that I try out Precision Sound Products's flared ports...has anyone used these before?
 

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Discussion Starter · #17 ·
So here's what I have planned so far...4.2 cube box tuned to ~29hz with a 6" PSP port (http://www.madisoundspeakerstore.com/flares/ports/vents/6flare-complete-kit/), with dimensions of 18" tall, 18" wide, and 32" deep. One of my friends has the exact same box, and he gets some massive windshield flex and clean output. Just waiting on an email back from Fi to see if I could pick up the woofer instead of them shipping it to me.
 

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There is a guy on DIYMA that is selling a couple of new (old style) Fi X 12s for I think $90 shipped each. I know nothing about the guy, but would be buying them for myself if I had a project for them.
 

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Discussion Starter · #20 · (Edited)
Are you just using the LPF on your amp ?
That one is set to about 150hz. I use the HU's one sometimes, but most of the time it's one "Through"? I think that's what it says haha. Usually I set the HU's to 120hz or 80hz for rock songs, but leave it on Through for hip-hop/rap songs.

There is a guy on DIYMA that is selling a couple of new (old style) Fi X 12s for I think $90 shipped each. I know nothing about the guy, but would be buying them for myself if I had a project for them.
That's tempting...I might pick up the Q15 and those if possible lol. Thanks!
 
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