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View Full Version : 3 12" subs in trunk?



brooklynjoy2008
10-21-2011, 04:13 AM
So I am new to the world of competitive car audio and have done hours upon hours of research and I save the hardest for last. I have a 2000 alero with plenty of trunk space, I have 3 mofo 124x's they need 2 cf each and I wanted to do sub back port back with slot ports to help brace the box but I cant do that cause I dont think I have enough room. If someone could help me with a good box design I would greatly appreciate it. Also I would like it tuned at 30 hz, I was thinking maybe subs front port back with a big horizontal slot. Or should I just use round ports and bracing and what the difference its hard to find GOOD info online because so many people have opinions without facts. I am a man about numbers which is what this is all about, so if you just heard this from someone or this is what you THINK and not what you KNOW please do not waste my time and yours talking about something you do not know about thank you .

Germ305
10-21-2011, 04:19 AM
Pm or talk to Don H,Pro Rabbit,or Moble Enclosures here on the forums. I am sure they could all design something for you based on your needs. :)

kushy_dreams
10-21-2011, 04:26 AM
pm ram designs, he does excellent work

duanebro
10-22-2011, 12:13 PM
So I am new to the world of competitive car audio and have done hours upon hours of research and I save the hardest for last. I have a 2000 alero with plenty of trunk space, I have 3 mofo 124x's they need 2 cf each and I wanted to do sub back port back with slot ports to help brace the box but I cant do that cause I dont think I have enough room. If someone could help me with a good box design I would greatly appreciate it. Also I would like it tuned at 30 hz, I was thinking maybe subs front port back with a big horizontal slot. Or should I just use round ports and bracing and what the difference its hard to find GOOD info online because so many people have opinions without facts. I am a man about numbers which is what this is all about, so if you just heard this from someone or this is what you THINK and not what you KNOW please do not waste my time and yours talking about something you do not know about thank you .

You said that you were new to competitive audio, what kind of class are you in? If you want to compete for spl you might want to look into a higher tuning frequency. I see many people saying they want to tune to xx frequency, but don't say why. Please give some more details as to what you what want to do with this build.

Duane
DB Designs
Grand Blanc, MI

disturbed471985
10-22-2011, 12:39 PM
I think a box of that size may have to be built inside the trunk. I mean unless you go one hell of a trunk opening...

Louisiana_CRX
10-22-2011, 12:46 PM
I think a box of that size may have to be built inside the trunk. I mean unless you go one hell of a trunk opening...

this

brooklynjoy2008
10-22-2011, 12:50 PM
I am going to join the as2 class in meca. as for my tuning choice it will be a daily setup when I am not competeing so I would like to keep it low.

captnfangdango
10-22-2011, 12:51 PM
whats the measurements of the space you have to work with?

brooklynjoy2008
10-22-2011, 12:59 PM
yeah I have to build the box in the trunk and its the first one I am going to be building so we will se how it turns out any tips would be greatly appreciated.

brooklynjoy2008
10-22-2011, 01:58 PM
the dimensions are 36x26x17 that I have to work with and still have room for batt and amps

brooklynjoy2008
10-22-2011, 02:10 PM
is it better to tune higher for spl? the spec sheet says to to it to 36.8hz is that the frequency the subs will be the loudest at?

Danometal
10-22-2011, 02:17 PM
You may have to sacrifice some port area with those dimension parameters, albeit aeroports may be your friends. However, in every box design I've modeled, the aeroports only let me tune down to like 33 hz or so. So, I always have to do slots for a lower tuning, which eats real estate in the trunk.

Is it an option to just use 2 subs with a beastly box?

kushy_dreams
10-22-2011, 08:04 PM
The frequency you will be loudest at is dependent upon your vehicle. Every vehicle, even if they are the same model, will peak at a different frequency. Your install plays a big part as well. Where you position the box, where you aim the box, what the box is tuned to, impedance rise of the subs within the box, the position of the subs and port within the box, the amount of sound deadening material you have. Those are all critical factors. And to top that off, some cars are tough to get good #'s out of.

Ronny
10-22-2011, 08:36 PM
Three 12" drivers in an enclosure just 3ft wide net dimension? Ehh... Perhaps staggered mounting the drivers and aero ports over or under the drivers (depending on placement) would work. It's kind of tough to fit the three woofers and a slot port on that sized baffle.

Moble Enclosurs
10-23-2011, 12:14 AM
is it better to tune higher for spl? the spec sheet says to to it to 36.8hz is that the frequency the subs will be the loudest at?

There does exist a specific resonant frequency different from the drivers free air resonance that can be figured for your setup. the recommendation from the spec sheet is without considering your vehicle gain, along with what type of enclosure and personal preferences you may have. So, to figure that out, its best to know all of the variables first, which will required measuring and computing for specific response matching. So, don't rely on the spec sheet for any kind of tuning factor.

brooklynjoy2008
10-23-2011, 12:35 AM
I can use aprox 39 wide I was leaving extra room but all of those dimensions are on the low end the 2000 alero has alot of trunk space but I am working with someone on a box design, still any advice on competing would help.

duanebro
10-23-2011, 01:03 AM
Have you thought about making a port you can change? That way you can switch to a higher tuning just for comps.

brooklynjoy2008
10-23-2011, 01:36 PM
you know a changable port is not a bad idea