Jump to content

 

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

80AM

JL Infinite Baffle Install T23

Recommended Posts

80AM

So I've been weighing my options about a subwoofer in my '16 T23 and I think I've decided I want to use JL's M12IB6 infinite baffle subwoofer. This sub is supposedly a whole different beast than the 10" JL or Wetsounds infinite baffle subs.

http://www.jlaudio.com/m12ib6-sg-wh-mar ... vers-91618

I decided to go this route because I take the false panel under the dash out and use that storage space as a place for my dog to lay out of the sun, storage for a soft cooler, and I transport my surfboards in the driver seat with the noses slid down into that storage space and the steering wheel locking them down. I really don't want to lose all that function to add a subwoofer there. I realize that I could fit a sub in a sealed box there and it would definitely play louder, but I'm ok with the trade offs I think.

So, having said that, my plan is to mount the woofer in the walkway behind the observer seat in the top half of that compartment, basically above the battery switch. My thoughts are that whole compartment will act as the "box" the woofer is in while letting the sound radiate throughout the cabin because it will be directing sound right out instead of in a box in that compartment. I realize the fiberglass itself is too thin to support the woofer so I'm thinking a backing panel, say 16" square of 1" marine grade plywood and then sandwich that to that fiberglass with the mounting bolts of the woofer. Probably will throw some damping material between the panel and the fiberglass to eliminate any potential vibration there. The seats should act well enough as a seal, my only concern is the gap above the cup holderscause cause a backwave to reach the front side of the woofer, but idk enough of the physics about that.

My thinking is that the backing panel will help support the weight of the woofer in the fiberglass and disperse the energy across that fiberglass section so that it doesn't vibrate and wobble from the force of the woofer, which would obviously be a problem. I realize that once I start cutting 12" circles in the fiberglass that I'm kinda stuck with that, so wanted to throw this out there and hear people's thoughts on it. I've got 2 Rev 10s on the tower and 6 XS-650s throughout and this is my first attempt at a sub on the boat. I know it's not "optimal" but is it going to be a complete disappointment? Anyone see any flaws I haven't thought of or ways to improve the install? Has anyone ever seen this on a Malibu/Axis?

Share this post


Link to post
Share on other sites
80AM

Anybody have any thoughts? Is the small gap that wraps around to the driver side to pass power cables and the small gap above the cup holders further back in the cabin enough of an opening to be a problem for an infinite baffle? I could theoretically seal those off most likely, at least with enough material to block the sound waves. I think using 1" marine plywood would stiffen the walkway panel enough to prevent it from vibrating but now I'm beginning to worry about the glovebox above it. I guess given enough bass, most things will rattle if not tightly secured or dampened.

Share this post


Link to post
Share on other sites
David
Posted (edited)

Infinite baffle subwoofers are an ideal solution for many boats, not all, but many. An enclosed subwoofer type, sealed or ported, will have a slight advantage over an infinite baffle type since the air-spring of the enclosure offers a more linear means of controlling cone motion and allows for greater excursion = more output. IMO, JL Audio designs and builds by far the best IB subwoofers. Loading a subwoofer into the pass-thru generates as much radiation fore as it does aft so you lose a little something in the cockpit with that approach. While an infinite baffle subwoofer is self-contained and self-damped, it does require a full enclosure. The difference is that the enclosure is large enough to be considered 'infinite' and without impacting the subwoofer's characteristics. And for an IB 12" the subwoofer would like to see an initial unobstructed cavity of perhaps 3 to 4 cu.ft. minimum. So the main purpose of the IB expansive enclosure is to provide front to rear acoustic isolation. The depth of the low frequency extension will be determined by the quality of seal in near proximity to the subwoofer and the isolation distance before the opposing front and rear radiation are allowed to meet at which point they cancel. If the enclosure is large, which it is, then 5 feet of isolation distance is plenty. Anything you can do to get a better seal in close proximity will only help. Certainly with an IB subwoofer, hard mounted to the boat structure, you're likely to incur more resonance of thin panels or part to part contact. But those sources of noise are usually easy to find and damp. If you consider this to be Option A, and Option B would be to mount a small sealed enclosure within the port or starboard compartment and use a vent in the pass-thru, then you are better off with Option A. The best option, 'C', is when you combine an enclosure with direct-radiation by sandwiching the pass-thru wall between the exterior-mounted subwoofer driver and the interior-mounted enclosure...but you're back to stealing some storage space.

               

Edited by David

Share this post


Link to post
Share on other sites
vanstone22
Posted (edited)

Hugely depends on your bass desire and tolerance. If you want to just have a bass boost, they are fine. I’ve had both JL and Rockford versions, but unless you’re pushing multiple subs, one doesn’t take me where I want to be. A solid 10” ported will outperform a 12” infinite baffle. 

If space is a concern, you could get a quality sub with a super low volume sealed box. 

My opinion is always go with 12” if space allows

Edited by vanstone22

Share this post


Link to post
Share on other sites
MFknK
On 4/10/2019 at 10:00 AM, David said:

Infinite baffle subwoofers are an ideal solution for many boats, not all, but many. An enclosed subwoofer type, sealed or ported, will have a slight advantage over an infinite baffle type since the air-spring of the enclosure offers a more linear means of controlling cone motion and allows for greater excursion = more output. IMO, JL Audio designs and builds by far the best IB subwoofers. Loading a subwoofer into the pass-thru generates as much radiation fore as it does aft so you lose a little something in the cockpit with that approach. While an infinite baffle subwoofer is self-contained and self-damped, it does require a full enclosure. The difference is that the enclosure is large enough to be considered 'infinite' and without impacting the subwoofer's characteristics. And for an IB 12" the subwoofer would like to see an initial unobstructed cavity of perhaps 3 to 4 cu.ft. minimum. So the main purpose of the IB expansive enclosure is to provide front to rear acoustic isolation. The depth of the low frequency extension will be determined by the quality of seal in near proximity to the subwoofer and the isolation distance before the opposing front and rear radiation are allowed to meet at which point they cancel. If the enclosure is large, which it is, then 5 feet of isolation distance is plenty. Anything you can do to get a better seal in close proximity will only help. Certainly with an IB subwoofer, hard mounted to the boat structure, you're likely to incur more resonance of thin panels or part to part contact. But those sources of noise are usually easy to find and damp. If you consider this to be Option A, and Option B would be to mount a small sealed enclosure within the port or starboard compartment and use a vent in the pass-thru, then you are better off with Option A. The best option, 'C', is when you combine an enclosure with direct-radiation by sandwiching the pass-thru wall between the exterior-mounted subwoofer driver and the interior-mounted enclosure...but you're back to stealing some storage space.

               

David, 

I have read many of your posts and greatly appreciate the knowledge you share.

 

Your option “C” is what I have been looking at doing in my A24 at the drivers kick plate. I was told this is a bad idea because it would be tough to insure a good seal between the 3 components(enclosure to kick plate wall to sub).

Do you disagree and think it is a good option to “sandwich” the kick plate wall between the sub and enclosure?

 

The A24 had quite limited space in this location. Especially with the heater. So I have decided that a sealed enclosure is going to be my best option. I will probably be limited in my subwoofer selection based on the space for the enclosure.

Share this post


Link to post
Share on other sites
David
On ‎4‎/‎26‎/‎2019 at 10:04 AM, MFknK said:

David, 

I have read many of your posts and greatly appreciate the knowledge you share.

 

Your option “C” is what I have been looking at doing in my A24 at the drivers kick plate. I was told this is a bad idea because it would be tough to insure a good seal between the 3 components(enclosure to kick plate wall to sub).

Do you disagree and think it is a good option to “sandwich” the kick plate wall between the sub and enclosure?

 

The A24 had quite limited space in this location. Especially with the heater. So I have decided that a sealed enclosure is going to be my best option. I will probably be limited in my subwoofer selection based on the space for the enclosure.

I've done the "sandwich" approach many times and it's fairly easy...provided you have enough smooth and flat wall surface to deal with. The technique is to pre-mount the interior enclosure, using a silicon sealer as a gasket, using a different hole pattern than the external woofer, with flush hardware that is then concealed by the rim of the woofer once mounted in place.

Btw, when considering whether to go sealed or bass-reflex, the entire port can be mounted external to the enclosure, which serves to reduce the enclosure size. Plus, you can place bends in the port tube with little consequence. The net ported enclosure will still be a bit larger than the sealed version, but an external port tube will shave enclosure space, and is just another option.

In general, I always recommend that you FIRST arrive at the exact dimensions and displacement of the maximum enclosure you can fit, and only then select the subwoofer driver and loading method based that cubic displacement. This will deliver optimal performance. Using the largest woofer that you can shoehorn into the enclosure won't produce a good result.

Share this post


Link to post
Share on other sites
MFknK
On 5/12/2019 at 2:27 PM, David said:

I've done the "sandwich" approach many times and it's fairly easy...provided you have enough smooth and flat wall surface to deal with. The technique is to pre-mount the interior enclosure, using a silicon sealer as a gasket, using a different hole pattern than the external woofer, with flush hardware that is then concealed by the rim of the woofer once mounted in place.

Btw, when considering whether to go sealed or bass-reflex, the entire port can be mounted external to the enclosure, which serves to reduce the enclosure size. Plus, you can place bends in the port tube with little consequence. The net ported enclosure will still be a bit larger than the sealed version, but an external port tube will shave enclosure space, and is just another option.

In general, I always recommend that you FIRST arrive at the exact dimensions and displacement of the maximum enclosure you can fit, and only then select the subwoofer driver and loading method based that cubic displacement. This will deliver optimal performance. Using the largest woofer that you can shoehorn into the enclosure won't produce a good result.

Thanks for the reply David. We are wrestling with options. It doesn’t appear that we will be able to load a box from the rear unless we go very small. I think a front loaded box is going to be the most viable option. Since that is the direction we will mostly likely go, I am going to measure for the maximum box size and see about getting a ported box in that location.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...