Rear Foward or Up Facing Subs?

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Rear Foward or Up Facing Subs?

By JustinHforHonda
- Tue Apr 01, 2014 11:24 pm #343945 Hello Forum,
I built my box and seat delete for my subs to be rear facing, as the consensus back then was that's the best way subs should face in a hatch. I'm going to be redoing my system and am thinking about the possibility of facing my new subs forward or upward to have a sleeker looking seat delete design.
So was wondering anyone's experience with subs facing in these different directions? Differences in SQ, SPL, Rattles...? I am not competing in sound competitions, just want it to sound good, and not be "wasting" or "losing" bass.
Here is my current seat delete/sub set up.
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The new design will still pretty much have to keep the subs right behind the front seats as the rear half of the design (my spare tire spot) is where all the air suspension components are.
Thanks in advance!
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By teal_dx
- Wed Apr 02, 2014 12:55 am #343950 I'm not an expert at this stuff. I always thought rear facing was best because the bass bounces off of the back of the car, making it louder up front and covering up noise from the subs that you would hear if they were facing up or forward.

Nice work you've done there :thumb:

By rustyrex
- Thu Apr 03, 2014 12:58 am #343953 I have been doing car audio for almost 20 years and before I became a engineer I held a MECP certification. If your enclosure is sealed it will not make a difference as far as loudness goes. If it is ported then having the subs face the rear bumper will always be louder in a hatchback. The hatch area gives the port a loading wall and will allow the bass to generate higher pressure. Sound quality is the only thing that will change with a sealed box facing forward or backwards. That is something that is personal preference. The best thing to do is build your box and try it both ways.

By JustinHforHonda
- Thu Apr 03, 2014 4:17 pm #343985 Thanks teal!
And thanks Rusty. Yes sealed box for me, unlike you I hold no degrees or certificates in engineering so simple and sealed boxes is what I'll be building lol. Good to know loudness should be the same though so like you said I'll test out the different directions of the sub and decide on my design from those results.
Was most likely going with a single or dual 12" set up but can't shake the idea of a single 15". I listen to everything but majority is hip hop/pop. Installed many 15"s rusty? Or anyone?[/quote]
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By teal_dx
- Thu Apr 03, 2014 4:40 pm #343986 Back in the day I had a few different dual 12" setups (this would be in my first car - 1991 Chevy Lumina lol) and tried a pair of sealed 15" Kickers one time and while I could feel it more and it rattled my car apart more, it just didn't sound as loud to my ears- or outside of the car as the pair of 12" sealed JL subs did. I noticed the same thing in other friends' cars, too- that 12" subs just sound louder in a trunk than 15" subs.

I'm sure Rusty knows the science behind this, please share :thumb:

By rustyrex
- Thu Apr 03, 2014 4:55 pm #343988 I have installed everything from a 6.5" DC sounds and American bass to a 24" Tantric sub in all kinds of vehicles old and new. If you tell me the brand and model of subs you want to use I can design a ported box for you with now problem.

As far as the 15" subs compared to the 12" subs it boils down to one thing. Volumetric efficiency.

A 15 will always be louder than a 12 if properly installed. With a 15 they are less forgiving with respect to enclosure design, power input, and vehicle dynamics. A example is your situation Brian. 15s fit in your trunk, but I'm sure the box was a decent size. So it took up more air space, raising the resonant frequency of the car while t the same time not allowing to woofers to properly breathe and let the bass output reach the cabin.
The 12s however had a smaller enclosure, so the resonant frequency didn't rise as much, and didn't take up nearly as much air space. This allowed the 12s to breathe more and be more efficiently yielding greater output.

A ported box will always be louder than a sealed box, no matter what. As long as it it designed properly. You can also use less power and have greater output with a ported box simply by changing the internal volume and tuning of the box.

By JustinHforHonda
- Thu Apr 03, 2014 9:04 pm #344009 Wow great info.
As far as loudness I have no concerns about being heard from outside the car or the likes. So maybe for that reason the 15 isn't needed. But more so I'm drawn to the idea of a 15" for its uniqueness and rarity compared to a 12" on top of what should be a capability of lower deeper bass. I'm an MTX fan and am looking at the MTX 5515 or 5512. My whole system is MTX (yeah OCD I know). MTX Thunder500.1 is my new amp. And I would build a rectangular sealed 1.5cf for the 15, nothing complex, all right angles lol

By 93sihatchguy
- Thu Apr 03, 2014 10:43 pm #344015 Nice work man. You completely took out the rear seats huh? What part of the valley are you from?

By JustinHforHonda
- Fri Apr 04, 2014 2:03 am #344051 Thanks! I've been living in and around Northridge/Reseda since my CSUN days, but I'm from the Antelope Valley lol.
And yeah did the old seat delete. I used a few DIYs like this one http://civic-eg.com/viewtopic.php?t=211 ... 2eea353adf
to get me started and adapted the ideas to fit what i was trying to do. here's a couple other angles for the rear speakers and the door hatch for the air ride.
[img][img]http://i63.photobucket.com/albums/h153/justinkase2114/rearspeakers.jpg[/img]

[img][img]http://i63.photobucket.com/albums/h153/justinkase2114/airtank-1.jpg[/img][/img][/url]
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By lalo
- Fri Apr 04, 2014 3:29 am #344062 Damn nice setup nice knowing that someone from the valley is on this forum.

By 93sihatchguy
- Fri Apr 04, 2014 8:33 pm #344109 Do you have your civic parked in a garage? That will attract so much attention! I wouldn't park it along Reseda Blvd in the CSUN area, too many break-ins. Not so sure about the AV, but I suspect it would be the same there too depending on what part of Palmdale/Lancaster you're from.

Anyway, what other components do you have in this custom install? Looks and sounds like it's loud as hell. Oh and is that an air compressor in your spare tire well? Must have spent some time and a good amount of $ for this project.
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By Virux
- Fri Apr 04, 2014 10:04 pm #344112 Most bass frequencies are omnidirectional. The larger the cone, the more omnidirectional it will be. I doubt you'll be able to tell a difference, but Rusty knows better than me. As for vibrations I'll just second for test them both.

By JustinHforHonda
- Sat Apr 05, 2014 11:48 pm #344141
Do you have your civic parked in a garage? That will attract so much attention! I wouldn't park it along Reseda Blvd in the CSUN area, too many break-ins. Not so sure about the AV, but I suspect it would be the same there too depending on what part of Palmdale/Lancaster you're from.


I do keep it in the garage, and have a cover i throw over everything if im parking it somewhere.

Anyway, what other components do you have in this custom install? Looks and sounds like it's loud as hell. Oh and is that an air compressor in your spare tire well? Must have spent some time and a good amount of $ for this project


MTX TX5 front and rear. the rears were really more because i wanted a true 5.1 surround sound set up. so also installed 1 MTX TDX35 for my center channel under the center dashboard vent pointing up reflecting off the windshield and its powered by the clarion XC1410 micro amp i fit under the passenger seat. and the JVC KD-AVX77 El Kameleon head unit is the dvd player and 5.1 Dolby Digital decoder.

blocked off the air flow with a thin alum sheet underneath, and the vent fits back over it and you cant even tell the speakers there
[img][img]http://i63.photobucket.com/albums/h153/justinkase2114/center2.jpg[/img][/img]
clarion mounted under the seat
[img][img]http://i63.photobucket.com/albums/h153/justinkase2114/miniamp1.jpg[/img][/img]

also made some tweeter pods
[img][img]http://i63.photobucket.com/albums/h153/justinkase2114/tweeter2.jpg[/img][/img]

the new amps are MTX THUNDER75.4, MTX THUNDER500.1 both to be installed with new design, and either MTX 5515-44 or MTX 5512-44 sub.

the air ride is Air Lift's Autopilot V2 management system. in the pic in the earlier post you can see in the spare tire well the 4gal pancake tank, and flow control harness i made. using a AZ OB2 compressor and riding on Ksport Airtech struts. I had a specialty shop run the plumbing so any leak or wear and tear type problem is covered which was important to me having no experience with air setups before, i wanted that safety net. but built and installed everything else myself.

she's not my DD so i don't have to rush installs and can baby her plenty. but have i spent some time and $? of course, but always worth it to see an idea or design come to fruition.
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By bigJOE671
- Tue Apr 15, 2014 4:14 am #344572 I have 1 12" kicker sub in a 1.81 cu ft ported box powered by 500 watts of power from my alpine amp. This is installed in my 94' Civic Si



I mainly play hip hop, rap, and trap music. Sometimes the some old school music

The box almost takes 2/3 of my trunk space but oh well. Two ports both facing the subs direction

I tried rear facing, front facing, and facing the roof.

Rear facing: yielded more bass output and rattled my trunk a lil. Sound quality was lower than front facing but you can only tell the difference if you really listen to it. I prefer my sub facing this way

Front facing: sounded clearer but didn't hit as hard as rear facing. Didn't really rattle my hatch at all.

Top facing: Didn't really like this one because I didn't really feel the bass as much as rear or front facing and sounded like crap. So I changed it immediately.

By JustinHforHonda
- Tue Apr 15, 2014 11:21 pm #344618 Nice info bigJOE! exactly what I was looking for and waiting to do too and finally got some time last weekend.

I dismantled my seat delete and got to play around with my 3 10s and the direction they faced...

Overall I didn't feel any one direction was worlds better or worse then another. The differences were minimal and quite subtle.

Rear Facing: seemed to be able to "hear" the bass the best, and like bigJOE noticed has a few extra rattles when pushing the volume. But I would agree that this results in the cleanest sounding bass.

Front facing: also like bigJOE I had much less rattling with the subs facing forward. With my set up the subs were facing directly into the back of the front seats, and this obviously made me feel the bass much more, but didn't sound as clear.

Up/Top facing: this is were i got a different result from bigJOE. Even though I also didn't feel the bass as much as front facing, it still had some of that sort of subsonic inner ear type boom that front facing has and rear facing does not have. And for that reason i do feel that rear facing was a tad bit clearer as far as hearing the bass, but to me the sound quality was still there in detail with the subs firing at the roof. Really seemed to be a little of both of the other directions. More boom, full low bass notes, with a minimal dip in SQ.

Wonder if this result, or part of it, is because of my seat delete design my subs are basically in the middle of my cars interior compared to the rear spare tire area where most subs are put in hatchbacks?

Again, each position was very close sounding all around, I had to go back and forth half a dozen times to decide the differences and which way sounded like what specifically.

So in the end, I'm going to go with a single 12 up firing for my next design.

Thanks for everyone's input and i'll try to update later once i finish the new box.
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