Trunk Setup Positioning

[jcarter1885 995]

When it comes down to the option of which way to fire your subs and port in a trunk I was wondering did the amount of power you were running made a difference if you have to fire your subs forward (into the cabin) or to the rear (back of the trunk)? I know that it can be a personal preference and is ususally done when people are competing or wanting more output fro m there setup but I was just curious does power level play a role even if it is a daily driver.

On a side note I have heard some of the low end is sacrificed when forward firing as well since it takes the waves longer to bounce off something, will a lower tuning help out with this issue? Will the issue be that noticeable if you were to have a tuning of 33-35hz vs. 31-33hz vs 28-30hz tuning, I know it is not that big of a difference in those tuning levels just curious as to which tuning level will have excellent lows and excellent ouput (daily driver ground pounder) with a forward firing design?

Thanks fellas just weighing all my options on designs before jumping in the water on a big build.

[Julian 641]

In the lumina when i was running my Fi bl 15" in a 3.5 Ft^3 box tuned to 32Hz, it was best to either place it forward and push it all the way to the back of the trunk so it was still facing forward or to put it all the way back to the seats facing rearward.

I noticed a huge loss of output when facing forward, the low end was not there, it wasn't as loud. Although mine was not sealed so this could of made a huge difference.

Sealing may have a huge impact on the output and the low end, I have a feeling if i would have done that the output would of been superb.

[jcarter1885 995]

thanks for the input Julian

[ssh 924]

I could be wrong so don't shoot me if M5, Impious, or anyone else intelligent states otherwise, BUT unless your doing a wall then I believe subs back works best.

Leave one of the rear seats down so the trunk isn't sealed from the rest of the car.

Or are you planning on having the rear seats down and have the subs fire directly into the cabin (like ultrisa's or onebadmontes setup? (and yes I know onebadmontes is IB but you get the visual))?

reread and see you stated about doing this ^

As far as that vs subs back, I have no input.

as far as regular tuning 33hz is a nice choice for output and sq.

Edited August 26, 2010 by stefanhinote

[jcarter1885 995]

I could be wrong so don't shoot me if M5, Impious, or anyone else intelligent states otherwise, BUT unless your doing a wall then I believe subs back works best.

Leave one of the rear seats down so the trunk isn't sealed from the rest of the car.

Or are you planning on having the rear seats down and have the subs fire directly into the cabin (like ultrisa's or onebadmontes setup? (and yes I know onebadmontes is IB but you get the visual))?

reread and see you stated about doing this ^

As far as that vs subs back, I have no input.

as far as regular tuning 33hz is a nice choice for output and sq.

I know what works best in the car to get a better sound (thats rear firing) and what is the best tuning frequency for a good blend of output/low end.

Im talking about if I go forward firing subs and port because of the amount of power Im running then I want to know what applies to firing forward?

Basically its a two-part question:

1. Are there power requirements that allow you to not operate firing your subs to the rear that well?

2. If so then what is a good tuning frequency for forward firing port and subs to get a good blend of low end (firts priority) then output (second priority)?

[Sir-Lancelot 216]

The loudest I have seen have been subs and port forward and completely sealed from the trunk. Your seats fold so that is an option for you.

[cheese20323 13]

I had tried several positions in a trunk, only one not done is sealing it up....

The one that worked best was port and subs back, then port back subs up, then port up subs up, then subs back and port back.

[jcarter1885 995]

I had tried several positions in a trunk, only one not done is sealing it up....

The one that worked best was port and subs back, then port back subs up, then port up subs up, then subs back and port back.

Thats not what im asking but thanks for sharing because i was thinking port back and subs up as well too. I wanna go subs and port to the rear, 2-12" subs (undecided and power is undecided but around 3500 or better). Im just wondering if there is a certain power level that will require me to go subs and port forward and sealing off the cabin from the trunk instead of whats best (port and subs to the rear).

[dvalue 17]

Ive had the best results firing forward and sealed.

[Duran 387]

Generally, for numbers, forward and sealed from the back. For a daily driver fire it to the back with plenty of space for the sound waves to get into the cabin.

[Notorious97200 339]

Generally, for numbers, forward and sealed from the back. For a daily driver fire it to the back with plenty of space for the sound waves to get into the cabin.

:fing34:It make sense !

[6APPEAL 7]

I've always found it was better to play with it based on the car it was going in, specifically as to whether the rear seat folded down or not.

In my G-body cars (GN, Monte Carlo, etc) I always had the best sound and pressure firing forward with the front sealed off from the trunk. And it did not matter the power level or tuning freq, it just sounded better and played louder and lower that way. But, note that these cars did not have a fold down rear seat. I've always taken the entire width of the trunk between the wheel wells with this body style car, so sealing the front off from the trunk just always made sense. Now it doing a single sub or a couple of small subs that do not require the whole area, it could be that firing back might work out for the best since you would not seal the trunk off from the cabin.

In the cars with fold down rear seats I always found that rear facing was best no matter the power level or tuning freq. It could have been mostly because fold down rear seats have a hard backing on them that does not allow good sound wave pass through into the car cabin.

In a hatchback, it was always best rear firing no matter the power level or tuning freq.

I've always preferred tuning at or below 34 Hz, but I'm more of an SQ type.

In the most basic terms it's going to come down to your experimentation to find what works best for you. Good luck and have fun with it.

[antonmiller 8]

try side firing everything not joking it was the best way for output in my car with a taller box...

[j-roadtatts 1,129]

Was working all weekend so I am a little late to the discussion.

I think when most ppl say they 'hear' more output from rearfacing, what they are really hearing is coloration of the sound. True lows should be felt and not heard.

when I was running only 5-600 watts I almost perfered the rearfacing too, ALMOST. NOW that I have upped the power I much prefer the super clean lows, and my brain will no longer except anything less. a side note, I have my BTL crossed at 50hz. SOOO much easier to get the true lows with more power and you can get rid of as much coloration as possible.

I know you are set on the rear firing, and are just going over the details, but I still wanted to give you my opinion.

Have you ever played with a 4th order BP box? thats always what a rearfacing setup sounds like to me, like the sub is in the next room and you are just audibly hearing and feeling what makes it to you. VERY colored in my opinion. I actully like the sound of BP boxes on some genres of music. eg. rap, house, techno, BBM, C&S. So thats why I ask about the BP. Very effecient. (had a BP in my last car)

[jcarter1885 995]

Naw Im not set on rear firing if forward firing is what im after, thats what the purpose of this thread was. Ive always had rear firing setups and loved them but never had a forward firing setup. The ones I did here that were forward firing where not sealed off and where horrible sounding to me but I cant judge that since it was not done correctly. More responses and input is appreciated, still have some time till this build gets started.

[j-roadtatts 1,129]

Naw Im not set on rear firing if forward firing is what im after, thats what the purpose of this thread was. Ive always had rear firing setups and loved them but never had a forward firing setup. The ones I did here that were forward firing where not sealed off and where horrible sounding to me but I cant judge that since it was not done correctly. More responses and input is appreciated, still have some time till this build gets started.

I am guessing horrible sounding because they where not powerfull enough to tune for the true lows, so you settled for the rearfacing for the added output of the BP effect of firing into your trunk. I think with 2000+ watts that this will no longer be a problem. IF you are after the TRUE lows that surrond you and pressurize the cabin without any colorization or audibleness then do forward facing with a low crossover point. (narrow the frequecy band you are giving the sub, via crossover*, to get only the TRUE lows without anything audible)

*via crossover oposed to from the BP effect, with the cleaner signal=handle more power.

[mrray13 30]

try side firing everything not joking it was the best way for output in my car with a taller box...

This, +1.

With extreme power levels, and I consider 3500+ as extreme, the absolute loudest, lowest system I ever built was side firing. It was in a Nissan Maxima, a pair of 12 Solo Xs, each one fired into a corner of the trunk with it's port. With a MA Audio HK4000d, two batteries and a hipo alternator, that car was beyond sickening to sit in. Like mentioned above, this was a taller, almost trunk filling enclosure, so that played a role.

Also, you are going to have to play around with it yourself as well. Although for me, side>rear>front, for sound and output.

[ulrisa 26]

I'd have to go with j-roadtatts on this one. I had the same exact results that he did really. Now I feel the lows more than I hear them, the trunk definitely added coloration when I had my rear firing 600 watt setup. Now I get a lot of loud, clean output with my forward firing sealed setup. I'm not really sure how power handling would affect it, I actually think it would be worse to fire to the rear with 3500 watts because it would be hard to keep the trunk actually closed/sealed (unless you really braced it). I don't think you would need to tune lower to compensate and hit the lows (depending on how low obviously), because as j-roadtatts said you really feel them more and that is probably why people think it is worse. Obviously sealing off the trunk is a big undertaking, but bracing the trunk to handle all that beat would also be a big undertaking.

As a side note I'm not sure if it is just the difference in cancellation or subs but my new system hits the punchy notes really hard. Good luck on whatever you decide!

[altoncustomtech 773]

Was working all weekend so I am a little late to the discussion.

I think when most ppl say they 'hear' more output from rearfacing, what they are really hearing is coloration of the sound. True lows should be felt and not heard.

when I was running only 5-600 watts I almost perfered the rearfacing too, ALMOST. NOW that I have upped the power I much prefer the super clean lows, and my brain will no longer except anything less. a side note, I have my BTL crossed at 50hz. SOOO much easier to get the true lows with more power and you can get rid of as much coloration as possible.

I know you are set on the rear firing, and are just going over the details, but I still wanted to give you my opinion.

Have you ever played with a 4th order BP box? thats always what a rearfacing setup sounds like to me, like the sub is in the next room and you are just audibly hearing and feeling what makes it to you. VERY colored in my opinion. I actully like the sound of BP boxes on some genres of music. eg. rap, house, techno, BBM, C&S. So thats why I ask about the BP. Very effecient. (had a BP in my last car)

I can attest to this as well, without a trunk even. In the van when I first installed the Hifonics system a few years ago I had set it up with the subs facing the rear of the van. While loading definitely played a part, there were lots of colorations and other unwanted effects from the subs firing into the hatch door such as the plastic panels vibrating and resonating. In it, there was very little difference in how loud it was but cleaned it up and got it sounding four times better with the subs facing forward. Aside from that, all my experiences with trunk cars has led me to being a believer in forward firing with the trunk sealed off. On vehicles with fold down seats one must do some extra work for it to work as well. Removing the cover and using a hole saw bit to make those ventilate is a ton of work but well worth it in the end IMO. Just my .02

[j-roadtatts 1,129]

I think people tune low and then can't "hear" enough output so they turn it around to make the FR peak higher/narrower or to acheive cabin gain. The problem now is that FR isn't as predictable, due to unknown trunk volume. Whenever you have a 3db shift in signal it will be audible and prehaps memorable.

My opinion is ppl that like the rear facing would be happier tuned higher or with a BP alignment, BUT maybe its the cabin gain that the rear facing gives. I am all about knowing the physics of why it happens.

I am glad to see Anton contributing, because I know he has done alot of testing on the subject lately. Interesting about the side facing. +1 for trying something different atleast. I assume the physhics behind it are either that the BP effect is making the FR peak at a more audible freqency or the cabin gain is just right.

AS Jay-cee knows my BTL is forward facing, sealed from the trunk, tuned 32hz in 5 cu ft and crossed at 50hz. When I want more audible output from my current setup I boost the EQ at 40hz, BUT I am in control of the effect when I want it. (which isn't very often) Ignorance is bliss, SO I guess some of us must be in BLISS.

My past setups include sealed, ported, and 4th order BP alignments. I tryed each box forward facing, rear facing, and firing up, but never sideways. I have owed hatchbacks(my favorite, love the loaded horn effect) coupes, seadans, and trucks(love the cabin gain), Never a van or a station wagon.