Thinking of sealing off trunk

[Jeffrey Crawford 0]

Probably a horse that's been beaten to death, but I've still got a couple questions. First off I guess the equipment in use would be a good place to start. Two Skar VVX V2 12s and a Synergy Audio WFO 15.1 amp wired to 1 ohm in the trunk of a cavalier. Listen to decaf, rock, and country so musicality is a factor. Only have one VVX in the car right now, so building a new box and deciding to forward fire and seal off versus rear fire is kinda where I'm at right now. I've never heard a sealed off box so don't have anything to reference to also. My gut feeling is sound quality would be better, especially on rock, it would meter well if sealed off properly, but would lose some of the boominess when listening to rap when compared to rear firing in a trunk. As far as the box I'm thinking 3.75 to 4 cu ft with a center slot port around 33hz. Any and all comments welcome.

[jcarter1885 995]

Some people use expanding foam to spray around box to get a nice seal. If you don't want to ruin your interior then lay down some tape or something as a barrier between foam and carpet. Once done depending how much your seats are covering, you could make beauty panels to pretty it up. Box plans sound good, usually just matters on sound preference weather forward firing or rear firing is best. But forward firing usually meters better.

[Jeffrey Crawford 0]

Thanks for the response. The sound preference is what I'll have to find out I guess. I may front fire the box and stuff blankets around it enough to tell if I like how it sounds tonally compared to what I'm used to with rear firing. My gut feeling is notes will sound higher in frequency than rear firing, but that may be a good thing. My single VVX seems to color bass deeper than I remember my Ov13 sounding. Left the car parked for a year and I'll be damned if the voice coils didn't rust up on the Ov13 even though trunk has always been dry as far as I could tell.

[jcarter1885 995]

Stuffing sheets, towels and pillows wont really give you the full affect to make proper judgement, at least for me it didnt. Big difference to actually being sealed off, just my .02

[///M5 2,833]

My gut feeling is notes will sound higher in frequency than rear firing, but that may be a good thing.

Your gut is confused. A note by definition is at A frequency. This means no matter which way your box points the note will still be at EXACTLY THE SAME frequency. Won't be higher, won't be lower. If that is why you are sealing your trunk you should rethink your goals/plans.

[Jeffrey Crawford 0]

Thanks M5 and Jay-cee. M5 I wasn't sure if the car's acoustics, or cabin gain, would change a lot from the two different set ups. As far as goals goes, everything I've read seems to point to front fired and sealed off having better accuracy AND higher spl. Seems like a win win if done right. 

[///M5 2,833]

Thanks M5 and Jay-cee. M5 I wasn't sure if the car's acoustics, or cabin gain, would change a lot from the two different set ups. As far as goals goes, everything I've read seems to point to front fired and sealed off having better accuracy AND higher spl. Seems like a win win if done right.

Did you not read my previous statement? Better accuracy? A note is a note. Not sure what you are trying to elude here, but it seems like forum nonsense stemming from somewhere else.

[Jeffrey Crawford 0]

A note is a note, no arguing that. What I have noticed though is my sub sounds one way not in a box, another way in a box, and yet another way loading off the rear of the trunk from cabin gain. I don't know what it will sound like sealed off. Have admitted to never hearing a front fired sub(s) sealed off in my first post. I will take a leap of faith and believe that two different ways of putting a sub in a car will produce the exact same sound. Thanks for everyone's help.

[///M5 2,833]

I never said that two different configurations will yield the same sound, I said they will play the same note when asked to play that note. Completely different topic.

Some cars succeed with what you propose and some fail. No general rule of thumb in car audio that always works. Exactly why I was interested in your goals as it may not at all match what you propose...

[Jeffrey Crawford 0]

Thanks M5. Maybe I didn't word things right earlier, but you just touched touched upon what I'm asking about as far as sound goes. Good example at least to me is the intro of Alice in Chains' Would. I can listen to it right at the box and musically sounds right, but close the trunk and get in the car and now it loses it's complexity. That's what I'm talking about with accuracy and whether or not front fired sealed off is more accurate sounding. If the two configurations don't yield the same sound, then one of them would have to be the more accurate sounding. On the flip side I've got Zip 1 Decaf, not really anything complex about these bass lines but I don't know how cabin gain would affect the two configurations. Louder? Less airspace so I can buy that. Not as loud? Not loading the sub off a surface so I could buy that too.

[///M5 2,833]

Cabin gain is also constant.

Curious, have you tried just venting into your trunk? Ie, just removing the rear speakers so the bass has a direct path without having to go through material?

It takes mass to stop a low frequency acoustic wave. This means if you have no mass in the way nothing will really be blocked. Of course at some point there is different loading in your trunk which will change the sensitivity in different regions, but it is also something you can eq to your liking.

Just beware. You may LOSE output by sealing off your trunk and forward firing. You also may gain. Just don't do this thinking it is an end all as that is flat out wrong. It is very dependent on the car as well. Certain ones respond much better to different aimings.

[Jeffrey Crawford 0]

Yeah I've actually don't have any rear speakers with a hole cut in the deck with some aftermarket grills. That did help, and you're spot on about being car dependent. Realistically it'll be something I have to try and see if I like. Subs back port back or port side is proven, just never heard front fired and I'm curious. 

[///M5 2,833]

If you are going to seal off the trunk, sell the Skar's and run IB.