The best way for base.

[M5V8 337]

"The sound settings on the amps haven't changed at all when swapping inclosures so no prob there. I just quickly put those ports in to see the difference, did change but not much."

Since you have changed the position of the sub as well as the box you will need to re-tune.

Only if the box was identical in shape / volume / design would the settings still be right. I'd be sticking the ports in and running through a re-tune.

Also... has the box build changed? ie- thickness of the wall material / interior material?

Edited December 22, 2011 by M5V8

[E36 M 9]

When i have the rear seats down it sounds good as there is plenty of bass coming through the ports but i don't want to have to drive around with the seats down. As soon as i put them up the boot becomes a sound enclosure in itself and blocks all of it, the inclosure was custom made to the boot so sealed off the rear to the front, hence why i ported it.

Yeah, same as my sedan, when the seats were down, was much louder as its not enclosed in the boot, but when its up its limited to noise etc. And it also might be the amp? I swapped amps half way through the year, my amp wasn't running my 15 at all, was barely running it in, so had to upgrade to a huge amp to make the sub run to its full potential

[Greg111 13]

Since you have changed the position of the sub as well as the box you will need to re-tune.

Only if the box was identical in shape / volume / design would the settings still be right. I'd be sticking the ports in and running through a re-tune.

Also... has the box build changed? ie- thickness of the wall material / interior material?

The inclosure is now gone, will start from scratch, will try the tuning thing once i'm done

When i have the rear seats down it sounds good as there is plenty of bass coming through the ports but i don't want to have to drive around with the seats down. As soon as i put them up the boot becomes a sound enclosure in itself and blocks all of it, the inclosure was custom made to the boot so sealed off the rear to the front, hence why i ported it.

Yeah, same as my sedan, when the seats were down, was much louder as its not enclosed in the boot, but when its up its limited to noise etc. And it also might be the amp? I swapped amps half way through the year, my amp wasn't running my 15 at all, was barely running it in, so had to upgrade to a huge amp to make the sub run to its full potential

The amp is an 800W powing an 800W sub so no prob there, it all came down to the inclosure difference.

[_Matt_ 42]

it's probably been asked but what is the make/model of both the amp and sub?

[hybrid 1043]

Ahh, I see the problem in your photos, sorry only just saw those!

You have bored two holes in the bass reflex wall. The rear wall of a sub enclosure is where the sound waves 'double up' and build up pressure so to speak. you unfortunately have detuned the box by doing that and it will sound a lot weaker.

You should only need 1 hole in the front panel that the sub mounts on. And use a thick pipe PVC tube or a proper plastic/nylon port. It should be about 15-20cm in length and sit inside the box while sitting flush with the front face of the box (same as the sub)

Use cotton/nylon wool inside.. just a scrunched up sheet of it is fine, and dont pack it too tight, only enough to fill about 1/4-1/3 the volume.

Face the sub backwards as you have. So you should have, the sub facing the back of the car, the port facing the back of the car, the bass reflx wall facing the front of the car.

This is your classic ported box.

Also one other thing, the box should be a little bigger for a 12 inch sub that you have there. not too much but just a bit wider each side should do it.

[Greg111 13]

Cheers for that Josh, will take that on board when making the new one, so you reckon face the sub to the rear of the car for best bass...

JVC 800W sub

Sony 800W amp

Sony 600W amp

Edited December 23, 2011 by Greg.

[_Matt_ 42]

JVC 800W sub

Sony 800W amp

Sony 600W amp

the reason I ask for the model numbers is to see if those amps are in fact 800w rms or max. Sony's aren't renowned for an rms rating of a high wattage like 800 even if bridged...meaning your sub is probably underpowered in the first place.

[Neal 544]

The Sony sub amp runs class D with around 300 watts RMS into 4 ohms at 13.8 volts. (engine running with alternator charging)

Used to produce good clean bass results with around 300 rms so the box is the key to overcome the challenges of the e36's well sealed boot.

Mind you , power ratings can be interesting. Had an PG amp rated at 4x25 rms for the 100 watt car stereo class that used to exist. At 12 volts into 4 ohms you got 25 watts. At 13.8 volts you got 75 rms x2 = 300 rms x1 bridge. This power was plenty for nice high quality sounds with more that enough volume to overcome car and road noise.

[Greg111 13]

The Sony sub amp runs class D with around 300 watts RMS into 4 ohms at 13.8 volts. (engine running with alternator charging)

Used to produce good clean bass results with around 300 rms so the box is the key to overcome the challenges of the e36's well sealed boot.

Mind you , power ratings can be interesting. Had an PG amp rated at 4x25 rms for the 100 watt car stereo class that used to exist. At 12 volts into 4 ohms you got 25 watts. At 13.8 volts you got 75 rms x2 = 300 rms x1 bridge. This power was plenty for nice high quality sounds with more that enough volume to overcome car and road noise.

Yep, the only problem to overcome is how it's all sealed together, when it was in the normal box it went great so power wise there is no problem, will make another box soonish.

[Greg111 13]

Ok giving this more thought, what's your guys idea on tyre well mounting, removing the wheel stay, insulating the well, making a platform for mounting the sub then port the floor? The old ladies Porsche had this done as it used to be owned by the CEO of SONY NZ and sounded great , no annoying vibration and lots of bass.

Has anyone done this kind of thing?

Edit: Just to add, i don't require a spare wheel as i can get an E46 M3 emergancy kit from work for cheap.

Edited December 30, 2011 by Greg.

[Greg111 13]

Something along these lines...

Haven't wired it up, just a mock up.

Removed the spare wheel stay and flipped the mag over so plenty of room for the sub magnet, will line the wheel well with dense foam and possibly put a couple of ports next to the sub keeping in toe with what you guys were saying about the do's and don'ts of porting.

[M5V8 337]

I'd mock up a box and see how it sounds. Your original issue was the sound quality.

This design is a compromise on sound quality for space.

I'm not saying it can't work, but you will need to be happy with the sound.

[Greg111 13]

Wired it all up last night, so far sounds great, 100% happy with it, did a bit of insulation, mounted the board firmly, no rattles at all.

[Neal 544]

Well done ! Pics ?

[m325i 709]

Looks cool. You should put a grill over it then you can use your boot with out any worries of damaging the cone.

[Greg111 13]

Will put a descent pic up with a descent camara over the weekend, yeah am thinking about the grill thing, although being the "toy" not a lot of things get put in the boot.