Free Air Subs?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=23815
Printed Date: June 11, 2024 at 8:19 PM
Topic: Free Air Subs?
Posted By: cobra2411
Subject: Free Air Subs?
Date Posted: January 03, 2004 at 12:17 AM
About 10 years ago I was into car audio, but I've kinda fallen out of touch with new trends and such. I was thinking about building a system for my 70 chevelle, and I was thinking of using a free air sub mounted in the rear deck between the 6x9's. I was looking arround on the net for free air subs and I couldn't find any. I'm not looking for a booming bass that will crumble buildings and can be heard 10 miles away. I just want a well rounded sound. The other requierment that I have is that the system doesn't intrude too much on the interior space. Should I just forget about free air and do a 10 or 12" sealed box? For anybody that doesn't know what a chevelle looks like, it's about the same size as a newer caprice or crown vic, like they use for taxi's and cop cars. Thanks for any help, David
Replies:
Posted By: boomer_106
Date Posted: January 03, 2004 at 1:54 AM
I think I remember seeing a Pioneer free air in crutchfield magazine. Kicker doesnt do free air anymore.
Posted By: bfog99
Date Posted: January 03, 2004 at 2:55 AM
infinity kappa perfects can be used in free-air applications.
Posted By: DYohn
Date Posted: January 03, 2004 at 10:10 AM
Free-air is fine and there are a few drivers that can still handle it. You will end up with a very low Q and somewhat boomy bass, but if that's OK there is no reason not to do it. That being said, if you have your 6X9s operating free-air in your rear deck and you also put a sub there, all three drivers will actually be operating into the large air volume of your trunk. This may or may not be a problem, but if you intend to push the sub with any significant power (say greater than 100 watts) I suggest you enclose the 6X9's so they are not affected by the much larger air volume that a sub can push around.
Posted By: Custom_Jim
Date Posted: January 03, 2004 at 6:41 PM
David, A lot of the new subs require a lot smaller enclosure than years ago. I'm into the older Chevrolets and I did a buddies 70 Monte Carlo a few years back and a 70 Malibu last year and and we just built a custom enclosures for the subs in both cars. There are a lot of ways to build one and not loose a bunch of trunk room you just have to get creative. Some of the 10" subs only require 3/4 cubic feet of airspace and 12" about 1 1/4 cubic feet. Also with an enclosure around the sub you have more protection around it to keep it from being damaged and allow it to operate and perform properly. Jim/Saint Louis ------------- 1968 Chevy II Nova Garage Find 2012
1973 Nova Custom
1974 Spirit of America Nova
1973 Nova Pro-Street
Posted By: Alpine Guy
Date Posted: January 03, 2004 at 6:41 PM
If you free air a sub, you can't feed it to much power either, like 1/4 of the recommended power. I have seen the Alpine type-s subs in free air applications, we fed 50 watts to each sub and they moved almost there full travel, still sounded good too.
Posted By: astro88
Date Posted: January 03, 2004 at 7:11 PM
O M G Dont carve up a classic! Build a box dude! it will sound much better too
Posted By: cobra2411
Date Posted: January 04, 2004 at 11:20 AM
astro88 wrote:
O M G Dont carve up a classic! Build a box dude! it will sound much better too
Well, it's kinda carved up... https://68.60.252.120/Chevelle_qtr_1.jpg It's getting two new quarter pannels, fenders, hood, misc. floor parts... I'm most likely going to build a box (or buy one) as I don't want a real boommy sound. Thanks for all the help David
Posted By: astro88
Date Posted: January 04, 2004 at 1:35 PM
Hey you do youre work youreself? Ive gotta say of the chevells from all body styles 70 is my fav.Ya gots a big block in that baby ? jus curious cause you may need some serious amps if you wanna hear youre tunes over that bbc roar!! ggggrrrrrrr
Posted By: cobra2411
Date Posted: January 04, 2004 at 2:36 PM
I'm doing the work myself with alot of help from my cousin. Right now it has a 307 in it, but someday I hope to have a big block 4spd combo in it. As for the system, I'm just getting ideas now, but here's what I'm thinking right now. 6.5" in the doors or kick pannels with tweeters in the dash.
6x9's in the rear deck
1 12" sub in a sealed enclosure right behind the seat. And depending on the head unit that I get, either 2 or 3 amps. About 50w rms to the front, 60-70 to the 6x9 and about 150 to the sub. If the head unit I get has three outputs I'll use three amps, If it only has two preamp outputs then I'll use a 2 channel in the front and 3 channel in the rear. Do you think the power levels are good for a balanced system?
Posted By: Durwood
Date Posted: January 04, 2004 at 3:13 PM
The levels sound good, although I might flip-flop the front and rear power settings. The 6.5"s in the doors would probably appreciate the added power, and the 6X9s are just for rear fill. 150 Watts to a single 12" should be fine as well. I'm more concerned about your engine... Can a Chevelle with a 307 even get out of its own way? (grin) Scott Gardner (1972 Dodge Charger w/ a 440. At 4000 pounds, I need every cubic inch of it..)
Posted By: astro88
Date Posted: January 05, 2004 at 7:26 PM
[QUOTE=Durwood] I'm more concerned about your engine... Can a Chevelle with a 307 even get out of its own way? (grin) I think u got a challenger there cobra!! he he hurry up w/ the bb bud! As for the system it sounds good, I can tell you i had a 12 in a seled box in the trunk of my 81 camaro , it sounded pretty good all around not boomy at all. What Brands are you lookin to get?
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