Anyone tried a Free Air Subwoofer in their GT?

[Type550]

Curious, has anyone here tried mounting a "Free Air" or "Infinite Baffle (IB)" subwoofer to their rear parcel shelf, as opposed to a bulky, sealed subwoofer enclosure taking up half their trunk space?

I'm just thinking whether a quality 8" or 10" Kicker Free Air subwoofer mounted to the center of the parcel shelf with appropriate sound deadening applied to the trunk floor would be a good solution, and save on valuable trunk space in the process. I know some cutting would be required of the metal to make it work, but it can potentially be mounted underneath the parcel shelf and shelf lining so it's hidden away if need be.

With the slant of that rear window, it's probably going to be impossible to fit a 10" free air subwoofer top-mounted, so maybe under-mounted would be the only option anyway. An 8" might be able to be top-mounted. Not sure?

Either that, or a really good set of 6" x 9" 3-way Coaxials (to replace the rear OEM 6.5" coaxials) to provide fuller bass without sacrificing trunk space?

I'm not too keen on installing a heavy, bulky sub enclosure in the trunk and losing valuable storage space and adding a lot of extra weight to the car.

Just throwing some ideas in the air here for comment/feedback.

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[rocknstang]

This is the only one I know of that's tried it. ForTehNguyen.

https://www.mustang6g.com/forums/threads/my-custom-audio-build.29714/

 

[DAZZA]

Curious, has anyone here tried mounting a "Free Air" or "Infinite Baffle (IB)" subwoofer to their rear parcel shelf, as opposed to a bulky, sealed subwoofer enclosure taking up half their trunk space?

I'm just thinking whether a quality 8" or 10" Kicker Free Air subwoofer mounted to the center of the parcel shelf with appropriate sound deadening applied to the trunk floor would be a good solution, and save on valuable trunk space in the process. I know some cutting would be required of the metal to make it work, but it can potentially be mounted underneath the parcel shelf and shelf lining so it's hidden away if need be.

With the slant of that rear window, it's probably going to be impossible to fit a 10" free air subwoofer top-mounted, so maybe under-mounted would be the only option anyway. An 8" might be able to be top-mounted. Not sure?

Either that, or a really good set of 6" x 9" 3-way Coaxials (to replace the rear OEM 6.5" coaxials) to provide fuller bass without sacrificing trunk space?

I'm not too keen on installing a heavy, bulky sub enclosure in the trunk and losing valuable storage space and adding a lot of extra weight to the car.

Just throwing some ideas in the air here for comment/feedback.

Yes I put two in the rear. I had dozens of combinations of with subs in the trunk etc. Finally decided to simplify my system completely and its pretty good,.

I have a pioneer class d amp in the trunk 4 channel driving two rear 8inch kicker subs mounted in place of the rear speakers and two 6.5inch coaxial pioneer speakers in the doors. I disconnected the tweeters in the A Pillars and the removed the mids in the upper door. I have a premium GT. I originally had a set of Hertz top of the range 3 way components now I have the top of the range pioneer coaxials without crossovers so wiring is so simple. I am a hifi enthusiast and have been building speakers and amplifier my whole life.

If you are not going to the effort of time alignment between the mid, tweeters and woofers you are better off just putting in a coaxial speaker, its sounds better.

I put sound deadening top and bottom of the parcel shelf and made timber spacers for the 8 inch subs and bolted them solid to the parcel shelf using all 10 bolts per Sub so they are solid. No vibrations and rattles anywhere.

There is plenty deep and controlled bass. I also mounted the DSP in place of the factory amp and tapped into the wiring harness. The only reason the DSP is in there is because I havent reprogrammed the DSP curve in the headunit I wanted a flat signal. This unit was the easy fix for that. I made my own preamp harness to tap into the existing connectors using info on this forum.

The subs where $100 each, let me know if you want to model number I will look it up

See Pics

 

[Type550]

Yes I put two in the rear. I had dozens of combinations of with subs in the trunk etc. Finally decided to simplify my system completely and its pretty good,.

I have a pioneer class d amp in the trunk 4 channel driving two rear 8inch kicker subs mounted in place of the rear speakers and two 6.5inch coaxial pioneer speakers in the doors. I disconnected the tweeters in the A Pillars and the removed the mids in the upper door. I have a premium GT. I originally had a set of Hertz top of the range 3 way components now I have the top of the range pioneer coaxials without crossovers so wiring is so simple. I am a hifi enthusiast and have been building speakers and amplifier my whole life.

If you are not going to the effort of time alignment between the mid, tweeters and woofers you are better off just putting in a coaxial speaker, its sounds better.

I put sound deadening top and bottom of the parcel shelf and made timber spacers for the 8 inch subs and bolted them solid to the parcel shelf using all 10 bolts per Sub so they are solid. No vibrations and rattles anywhere.

There is plenty deep and controlled bass. I also mounted the DSP in place of the factory amp and tapped into the wiring harness. The only reason the DSP is in there is because I havent reprogrammed the DSP curve in the headunit I wanted a flat signal. This unit was the easy fix for that. I made my own preamp harness to tap into the existing connectors using info on this forum.

The subs where $100 each, let me know if you want to model number I will look it up

See Pics

Oh man, what an awesome setup! Very well done!

I was thinking of retaining/using two high quality 6.5" coaxials in the rear parcel shelf, and just mounting an 8" or 10" sub underneath the center of the parcel shelf, but it looks like that center bulge will be an issue?! :(

 

[DAZZA]

Oh man, what an awesome setup! Very well done!

I was thinking of retaining/using two high quality 6.5" coaxials in the rear parcel shelf, and just mounting an 8" or 10" sub underneath the center of the parcel shelf, but it looks like that center bulge will be an issue?! :(

Thanks. So I originally had a set of coaxials in the rear and a 12 inch sub in the trunk in a box. I find the rears a waste of time and actually did not enjoy the sound, so I took them out and left open space for awhile and it sounds better to me. The fronts give more than enough volume and pretty decent bass just not that low sub bass. I can drive these coaxials to the point where its thumping ear damaging levels without any distortion. So with the two 8 inch subs in the parcel shelf they don't actually need to work to hard to produce very low sub bass to fill in where the 6.5inch fronts simply cannot get to. Outcome is nice a simple and you don't lose your trunk. The openings for the rear speakers are about 7inch and the actuall 8 inch kicker woofer internal measurement was about 7 inch and with the surround about 8 inch. You do not need to cut into the parcel shelf, but you will need to make a timber spacer and mount the subs from underneath as there is no room with the rake of the rear windscreen to get the sub in from the top unfortunately.

I took a picture of the sub from underneath so you can see the make.

 

[vnzbd]

Nice install. I like the simplistic approach.

 

[Type550]

Thanks. So I originally had a set of coaxials in the rear and a 12 inch sub in the trunk in a box. I find the rears a waste of time and actually did not enjoy the sound, so I took them out and left open space for awhile and it sounds better to me. The fronts give more than enough volume and pretty decent bass just not that low sub bass. I can drive these coaxials to the point where its thumping ear damaging levels without any distortion. So with the two 8 inch subs in the parcel shelf they don't actually need to work to hard to produce very low sub bass to fill in where the 6.5inch fronts simply cannot get to. Outcome is nice a simple and you don't lose your trunk. The openings for the rear speakers are about 7inch and the actuall 8 inch kicker woofer internal measurement was about 7 inch and with the surround about 8 inch. You do not need to cut into the parcel shelf, but you will need to make a timber spacer and mount the subs from underneath as there is no room with the rake of the rear windscreen to get the sub in from the top unfortunately.

I took a picture of the sub from underneath so you can see the make.

Love it! Are those Kicker CompC8 subwoofers suitable for "free air" use, or are they designed for smaller sealed enclosures?

 

[DAZZA]

Love it! Are those Kicker CompC8 subwoofers suitable for "free air" use, or are they designed for smaller sealed enclosures?

Thanks Mate!....They are designed for free air or boxed. I researched it at the time and others had used them in free air applications. It was actually a risk and I wasn't certain it would work. Boy was I surprised how much low but controlled bass response I got. If you turn it up the really thump and do not seem to reach there limit before you start to think you going to burn out the cables. Also I had to turn the gain down on the Sub channels as they were overbearing so they are sensitive enough and not short on bass.

They are are really inexpensive nice set of Subs. I paid $115 Aussie $$ each.

Having the trunk back is also nice. I am now thinking of buying a small 4 channel amplifier with built in DSP and install it where my current DSP is under the passenger footwell, this way I can get my spare wheel compartment back and put in a spare tyre.

 

[mfenske]

I've not done an IB (Free-Air) install in a Mustang (heck I don't own one yet) but I did have one in my 2012 Sonata Turbo and LOVED it!!! FWIW I was running a JBL GTO-1514. There's a few guys on diymobileaudio.com that have and they seem to like them too. Essentially the trunk acts as a very large "sealed" enclosure so they're typically very good at hitting low frequencies, take up little room, and require less power than most applications for output that's equal to what you'd need in a sealed application. I'm looking at a GT (not sure if Vert or Fastback) and if I do it will DEFINITELY have an IB install.

 

[DAZZA]

I've not done an IB (Free-Air) install in a Mustang (heck I don't own one yet) but I did have one in my 2012 Sonata Turbo and LOVED it!!! FWIW I was running a JBL GTO-1514. There's a few guys on diymobileaudio.com that have and they seem to like them too. Essentially the trunk acts as a very large "sealed" enclosure so they're typically very good at hitting low frequencies, take up little room, and require less power than most applications for output that's equal to what you'd need in a sealed application. I'm looking at a GT (not sure if Vert or Fastback) and if I do it will DEFINITELY have an IB install.

Gee that JBL looks like a nice Sub. It would be great if you can install a larger single Sub rather than two 8 inch Subs, however I get the feeling that the IB design can lend itself to not have a boomy, uncontrolled base response and the larger the woofer the more problematic this can become. This is just a thought as I do not have experience in this area. The 8 inch's are small and Bass is tight and controlled enough for such a large enclosure. These are just my thoughts.

 

[mfenske]

Dazza, completely false. So long as the woofer's got the motor force properly designed for its size it won't be boomy and the IB configuration actually works as an "infinitely" large sealed enclosure so it's the exact opposite. Basically what you're doing is "tricking" the speaker in to thinking it's in a huge enclosure and that's why a woofer with a Qts value in the .5 to .7 range works so well here. If you want to learn more diymobileaudio.com has more info than you'll ever need.

EDIT-When it comes to IB woofers "There's no replacement for displacement" and why many guys use 15's and 18's :-)

 

[DAZZA]

Dazza, completely false. So long as the woofer's got the motor force properly designed for its size it won't be boomy and the IB configuration actually works as an "infinitely" large sealed enclosure so it's the exact opposite. Basically what you're doing is "tricking" the speaker in to thinking it's in a huge enclosure and that's why a woofer with a Qts value in the .5 to .7 range works so well here. If you want to learn more diymobileaudio.com has more info than you'll ever need.

EDIT-When it comes to IB woofers "There's no replacement for displacement" and why many guys use 15's and 18's :-)

Sorry, yes you are correct. I did not explain very well. Its not like a measured the volume of my trunk and found a Subwoofer with the right specs that suits the volume. I am surprised there are not more IB setups in cars. Thanks for your advise.

 

[Type550]

Thanks Mate!....They are designed for free air or boxed. I researched it at the time and others had used them in free air applications. It was actually a risk and I wasn't certain it would work. Boy was I surprised how much low but controlled bass response I got. If you turn it up the really thump and do not seem to reach there limit before you start to think you going to burn out the cables. Also I had to turn the gain down on the Sub channels as they were overbearing so they are sensitive enough and not short on bass.

They are are really inexpensive nice set of Subs. I paid $115 Aussie $$ each.

Having the trunk back is also nice. I am now thinking of buying a small 4 channel amplifier with built in DSP and install it where my current DSP is under the passenger footwell, this way I can get my spare wheel compartment back and put in a spare tyre.

Hey Dazza, I contacted Kicker Support about those CompC 8 DVC subwoofers you're using, and they confirm that they will work fine in a free air application, however, they should not be driven more than 50% of their max RMS rating (so 100W RMS max per channel) in a free air application.

The Kicker support guy said to wire them onto the Focal FPX 4.400 SQ Amp's channel 3 / 4, with each woofer wired in parallel to those channels for a 2 Ohm load (with the X-Over set to LPF). Should get 100W RMS to each woofer in that configuration using that Amp

 

[DAZZA]

Hey Dazza, I contacted Kicker Support about those CompC 8 DVC subwoofers you're using, and they confirm that they will work fine in a free air application, however, they should not be driven more than 50% of their max RMS rating (so 100W RMS max per channel) in a free air application.

The Kicker support guy said to wire them onto the Focal FPX 4.400 SQ Amp's channel 3 / 4, with each woofer wired in parallel to those channels for a 2 Ohm load (with the X-Over set to LPF). Should get 100W RMS to each woofer in that configuration using that Amp

I don't think you have to worry about the power. I am driving them with my 130wrms per channel pioneer amplifier using only the one set of terminals on each subwoofer (4ohm load) having more power is not a bad thing. I am sure I hardly use anywhere near 50w rms as they are so efficient at producing bass and going loud. I am consider replacing my dsp and power amplifer with the audison bit 4.9 which is (i think) 70wrms per channel (4channels) for a really simple setup

 

[Type550]

I don't think you have to worry about the power. I am driving them with my 130wrms per channel pioneer amplifier using only the one set of terminals on each subwoofer (4ohm load) having more power is not a bad thing. I am sure I hardly use anywhere near 50w rms as they are so efficient at producing bass and going loud. I am consider replacing my dsp and power amplifer with the audison bit 4.9 which is (i think) 70wrms per channel (4channels) for a really simple setup

That Audison amp is pretty sweet! Should work out great! I'm looking at going with a Focal FPX 4.400SQ amp, which is also 70W RMS per channel @4 Ohm.

Trying to decide between the Focal Flax 6.5" components for the front OR Hertz Mille PRO 6.5" components. Both look like awesome 3-Way speakers. Hertz are slightly more expensive.

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