Building a better box for MY vehicle

[smashedz28 110]

Lately I've been pretty frustrated with my sub stage in my vehicle. I am not any kind of box designer but I can and have built my own from others blueprints.

I've always helped my friend with systems in his 08 Grand Prix. I have installed a lot of my enclosures in his vehicle with good results. Then I put the same boxes in my vehicle and get something totally different. Every vehicle is different I understand this. We both have trunk cars. Mine is an 11' Malibu. He clearly has a slightly bigger trunk than I do.

What I'm looking for is a better low end. The boxes I've used have all been tuned around 30-32ish. What do I need to take into consideration to build a box to excel in my vehicle?

What bothers me is how much I've spent vs what he has spent. His electrical is bone stock, 4ga wire and an audiopipe1500. Nothing more. I've got bigger wire, nice hu, 2nd battery, better amp I suppose (saz1500). Same set of sa12s in the same box I use in his vehicle sound 10x better than mine. I just put a single Fi Q 12 in his yesterday and hands down without even adjusting anything hits so much lower than my 2 12's or even better than the same Fi q in the same box in my vehicle. I've tried pointing the box forward but immediately noticed a loss in lower frequencies.

What am I missing here? As far as a box design how do I incorporate this smaller vehicle into the equation?

[Shogen 325]

obviously his car/trunk is 'resonating' at a lower frequency which may be lowering the tuning a bit.... maybe even the shape is effecting the sounds of the 'lows'... have you tried a box tuned lower than 30hz to see how it sounds?

[smashedz28 110]

No I have not. I can't be 100% sure my boxes are tuned in the low 30's like I've been told. Had 1 built by Rick other designed by bromo. Do you think tuning lower may help? Money isn't as good as it used to be for me. I surely can get a sheet of wood but I would like to have a better idea of what I need so I can give that info to whoever I have design it

[Shogen 325]

i'm shooting out ideas... not certain about any of what i said ... lol ... sorry

 

 

No I have not. I can't be 100% sure my boxes are tuned in the low 30's like I've been told. Had 1 built by Rick other designed by bromo. Do you think tuning lower may help? Money isn't as good as it used to be for me. I surely can get a sheet of wood but I would like to have a better idea of what I need so I can give that info to whoever I have design it

[smashedz28 110]

Lol thanks. I kinda thought something like that also but don't have time to build a ton of boxes and test that way. Was hoping someone has dealt with something similar and can point me in the right direction.

[ricksi30 923]

Have you tried a Malibu forum? Could be a waste of time but I have learned a lot of vehicle specific stuff on the Maxima forum that I am a part of.

[smashedz28 110]

I've looked at the malibu forum in the past. Not really too audio specific. There thoughts of a nice sounding system isn't mine. Think maliboom is there but he does walls as far as I know. I'll check it out again. I guess this this topic could apply to all trunk cars. How do we work with cabin gain? Obviously for my application building a box to speaker specs isn't helping me. I need to build a box specific to the car AND speaker.

[Shogen 325]

yes... my only guess is your friend's trunk being bigger helps the low end carry or amplify it.... how can you make yours 'bigger'???... well have you tried forward firing and sealed off completely???

 

 

I've looked at the malibu forum in the past. Not really too audio specific. There thoughts of a nice sounding system isn't mine. Think maliboom is there but he does walls as far as I know. I'll check it out again. I guess this this topic could apply to all trunk cars. How do we work with cabin gain? Obviously for my application building a box to speaker specs isn't helping me. I need to build a box specific to the car AND speaker.

[RiottStarr 5]

It has to be your box. I've heard 2 AA Mayhem 12's get stupid low in that same car.

[Shogen 325]

umm... appreciate your certainty on the subject but those aren't the same woofers and OP didn't express issues with loud as a whole but the low end... different equipment yields different results which is why OP has been trying same equipment in different vehicle trunks

 

 

It has to be your box. I've heard 2 AA Mayhem 12's get stupid low in that same car.

[smashedz28 110]

It has to be your box. I've heard 2 AA Mayhem 12's get stupid low in that same car.

Yes, it is my box. How do I fix it? Lol

[Quentin Jarrell 671]

It's obvious transfer function is affecting output. Only way to know how to work with it is measure the responses in each vehicle.

[smashedz28 110]

yes... my only guess is your friend's trunk being bigger helps the low end carry or amplify it.... how can you make yours 'bigger'???... well have you tried forward firing and sealed off completely???

 

 

I've looked at the malibu forum in the past. Not really too audio specific. There thoughts of a nice sounding system isn't mine. Think maliboom is there but he does walls as far as I know. I'll check it out again. I guess this this topic could apply to all trunk cars. How do we work with cabin gain? Obviously for my application building a box to speaker specs isn't helping me. I need to build a box specific to the car AND speaker.

Shogen, I tried forward firing but I did not seal it off. As it sat it was a tight fit. Maybe a few inches on each side. I didn't care for the sound, I felt that I lost my low end pointing the box that direction. I should have used some blankets or something but I didn't. Pain in the ass to remount all the amps again and turn it around if its not going to do what I want. I strongly feel its my box and a certain spec needs to be adjusted weather it's changing the tuning freq or adding or removing port area? I don't know.

[smashedz28 110]

It's obvious transfer function is affecting output. Only way to know how to work with it is measure the responses in each vehicle.

What do I need to use for this?

[Quentin Jarrell 671]

Some type of rta or db meter that will allow you to play a sound sweep to see ripples in response.

[smashedz28 110]

Don't have money for an RTA or access to one that I know of. Lets say I did how would I translate that info into my enclosure? Maybe the meter shows that I'm lacking in the 30-50 range? Then what do I do with that information?

[Quentin Jarrell 671]

http://www.parts-express.com/term/dayton-emm-6?srch=Dayton+EMM-6

 

 

Those are pretty cheap units.

 

 

If the RTA showed a loss in response form 30-50 then you have two choices.  EQ all the ripples (peaks) down to the level of 30-50 hertz output.  Or build an enclosure with an increased ripple at those areas to compensate.

[smashedz28 110]

Not to badly priced! I expected $500+. I assume I need both items? Microphone and software? Ill kick this idea around. Also would need to find a box designer who could properly account for my findings. I have the 80prs as a head unit. I haven't played with the EQ all that much. That's where I'll start. Should I invest in a separate EQ to help or is the one in the head unit adequate?

Thanks for your help so far guys. Very much appreciated!

[Quentin Jarrell 671]

not sure about the eq on that head unit.

 

 

The only way the info will be helpful is if you know the free air out put of the box.  So you would first measure the enclosure out of the vehicle to get a base reading.  (this is much easier to do with a sealed enclosure that has a flat response)Then come base the open space reading with the reading in the car to see how the car is affecting output.  

[ricksi30 923]

That head unit eq is plenty capable.

[Julian 641]

With the low end in my experience I've always had the best results from larger lower tuned boxes.  My current box is about 3.8 cubes before displacement so my Xcons get around 1.6ish cubes each and my tuning is at 35 and with ease on only 125w per sub it'll drop down into the low 20's without issue.

Edited July 29, 2013 by Julian

[smashedz28 110]

Little bit above my skill level but still a feasible task. Was hoping for a easy fix "tune lower or more port" lol. But I get what your saying. Guess I can kick this around till payday and see what I decide on. Any other ideas or suggestions please post. I'm trying to make this adjustment on a slight budget but really eager to get the sound I want from it. Thanks again Quentin!

[smashedz28 110]

With the low end in my experience I've always had the best results from larger lower tuned boxes.

Box is about as big as I can go with it and still get it in there. I thought it may have been the remaining trunk space after the box was in there was my problem. When the box is in its a tight fit all around. Passage space for air to travel to the front of the car is very little. I threw a single 12 enclosure in there and had the same problem.

[Julian 641]

With the low end in my experience I've always had the best results from larger lower tuned boxes.

Box is about as big as I can go with it and still get it in there. I thought it may have been the remaining trunk space after the box was in there was my problem. When the box is in its a tight fit all around. Passage space for air to travel to the front of the car is very little. I threw a single 12 enclosure in there and had the same problem.

I would take out the rear deck speakers and use that as a passage for sound to travel through. doing a truck wall may help with some of the cancellation.

[Quentin Jarrell 671]

With the low end in my experience I've always had the best results from larger lower tuned boxes.

Box is about as big as I can go with it and still get it in there. I thought it may have been the remaining trunk space after the box was in there was my problem. When the box is in its a tight fit all around. Passage space for air to travel to the front of the car is very little. I threw a single 12 enclosure in there and had the same problem.

this is not always the case. my ethos in the same size box 3 feet tuned to 32 for the 15 has a flat response with a F3 of ~28. In the same size box tuned to 36 it gets ~3db gain from 30-50 with an f3 of ~29. going with a larger box with same tuning only results in a bigger peak at tuning frequency, not any more lower extension. Edited July 29, 2013 by Quentin Jarrell