ok this is my situation i currently have a 2012 Mercedes C350 and just purchased audison fronts and audison rears , audison bit one , and a hertz hx300d 12" sub 600 watt rms 1200 peak
all powered by a audison voce 5.1k 5 channel amp that has 1000 watt rms at 2 ohms for subwoofer.

So i had it installed at the shop and the box was a ported custom built box with the ports on top and the sub firing towards the trunk and had the amp rack installed behind the folded down back seat.

I got it back and the bass just wasnt entering the cabin at all and the rear speakers arent in the deck but in the back doors and after alot of reaserch i found that everyone says mercedes trunks especially newer are absolute bass traps.

So i took it back again and had them remove the stock sub from the rear deck wich is a huge job cause you have to take everything apart. I was hoping that bass would enter the cabin better but thats when everything fell apart:(

On deeper bass notes it rattles the plastic rear deck REAL bad , not that normal rattle thats accociated with normal bass doing usual rattle but like a flaping rattle and it is just unnacceptable in a Mercedes. The sharp sq bass notes are fine though but i listen to hip hop so alot of the low bass notes hit.

It didnt flap rattle the rear deck before when i still had the stock rear deck sub in but i had only 400 watts running to the SVC hertz hx300 sub so it probably didnt have enough power to rattle , it started making that noise when i took stock sub out for more cabin bass and put the double powerfull amp in at same time and used the DVC HX300d instead of SVC sub so i think it will be same outcome even if i put the stock sub back in.

So i brought it back yet again and the installer tried to fix it and i just got a call saying he tried doing something and it flap rattles just as bad still and now im left with a choice and this is where i am desprate for advice:worried:

He said these are the choices i have
A) There is a rear middle pull down arm rest that that when you pull down is this black plastic wich would lead to trunk i think if you cut it out somehow
He said he can build a band pass box for the single 12" hertz hx300d and have the sub mounted sideways i think and cut out a hole in that plastic and port the band pass box directly through the hole wich he said would carry the bass right into the cabin and have no rattle on rear deck
                                             OR
B) since i have a 1000 watt 2 ohms rms amp i could do 2 12" hertz hx300d in a sealed box firing at the back seats and would still cut that hole in the arm rest

Also here is a few pics i found but still dont know wich choice to pick
Man i dunno what to do and i need advice , i just want pound hard bass with no rattle that can enter my cabin or hit my plastic rear deck and sound well in hip hop. Im 6 GRAND into this and wanna be done with this and get my car back

 

Mann, just cut the plastic off that arm rest and use a ported box facing into the cabin and seal it off from the trunk.  When you dont have passangers in the back, drop the rear seats down, and when you do have passangers in the back then drop the arm rest down.

 

This ^ is what I am doing on my next build.

Btw, welcome to ssa.

 

Please get familiar with the rules and stuff.

I'm a do a 4th order in my cadillac sts for 2 12 ethos on a saz 3500 with the port going arm rest to avoid the rattle I had a ported box sealed off but it made my rear seats look like jelly which in turn vibrated the rear deck since there bolted to it

the rattles should be address with CCF (closed cell foam) regardless.  no reason that removing the stock sub and/or rear speakers would cause rattles that couldn't be address easily with some isolating material like ccf. 

 

of the other options. a correctly designed bandpass box firing through the arm rest would also be great. 

 

the fact that a shop cannot address this scares me. 

tell me about it , this shop has done some sick work as i am a stickler when it comes to reaserching and they seem good so i dont understand all these problems and they take forever to get stuff done cause they are super busy at all times cause they only have 2 guys. But im invested now and am hoping this works out.

This is why i need advice so bad!! I wanna go in when it opens and have a plan ready to go but i havent found many newer mercedes subwoofer storys on the net so i am hoping someone has been there done that lol.

Here is a few designs i found on the net for armrest ported designs

http://i61.tinypic.com

Brace the rear deck and it will stop flopping like a fish. If your seat folds down, do as stated above. Other than that possibly having the sub and port on different walls of the enclosure is causing cancellation. Have you tried changing the direction the box is firing in the trunk to see if there is any acoustic difference?

If this shop was good, they would have understood the issue here and you would never have been in this position.

nice car

Brace the rear deck and it will stop flopping like a fish. If your seat folds down, do as stated above. Other than that possibly having the sub and port on different walls of the enclosure is causing cancellation. Have you tried changing the direction the box is firing in the trunk to see if there is any acoustic difference?

the box is custom built right into the trunk so i cant get back there to even see where the noise is and ya i agree they should have known this issue in the first place.

 

Im just worried im going to have the box design changed and pay all this money only to run into more problems!

 

What are common problems of bandpass boxes ported into the cabin via armrest?

Shitty response from a poorly designed box. 95% of all shop bp boxes I've heard are jacked.

 

Brace the rear deck and it will stop flopping like a fish. If your seat folds down, do as stated above. Other than that possibly having the sub and port on different walls of the enclosure is causing cancellation. Have you tried changing the direction the box is firing in the trunk to see if there is any acoustic difference?

the box is custom built right into the trunk so i cant get back there to even see where the noise is and ya i agree they should have known this issue in the first place.

 

Im just worried im going to have the box design changed and pay all this money only to run into more problems!

 

What are common problems of bandpass boxes ported into the cabin via armrest?

 

Have you searched what other people have had success with in that participator vehicle? A bandpass box plays a very narrow frequency range and is very peaky sounding. I doubt you would be happy with a bandpass if you are after SQ. Ask the shop if they can demo another vehicle for you that they have installed a BP in and see what you think. I personally have my port and sub firing into the cabin. 95% of the time I roll with only the ski pass open. I only gain a a slight gain in output with the seat down and that's only when I am wailing on it. An easy route to brace a rear deck is block up off the top off the enclosure. cheapest sound deadener you will ever do. If the plastic is what's rattling then put foam under it. Hold your hand on the rear deck and see if it stops rattling.

I would do a well designed 4th order BP, ported through the ski pass. It's time to spend money on some sound deadening. It doesn't matter if you go out and spend 20k in audio, if you don't pay attention to deadening, you'll always just be another vibratin' shakin' hooptie.

 

Edit - Meaning you buy other ultra high end equipment. Lol I'm an Audison dealer and know that AVK6's and AV5.1's are nowhere near 20k.

Edited February 13, 201411 yr by gprestonmoto

You can design a bandpass to have a response as flat as any standard 4th order vented.  You can also have the needed bandwidth required for your application.  It is all how you design the enclosure and the drivers you use...