IDMAX 15s - Infinite Baffle – Rear Deck vs Forward Firing

[Majik]

I have been patiently waiting to install a pair of IDMAX 15s IB since the beginning of winter. Now that the weather is showing signs of cooperating (I'm in the Chicago area), my level of motivation is ever increasing.

This will be my first IB install and I’m having a hard time deciding if I should mount them on the rear deck, firing up towards the rear windshield; or forward firing through the back seats (which are leather and don’t fold down). The vehicle is a highly modified 1997 T-Bird with a large rear windshield that might provide some pseudo-horn-loading benefits, but so many of the IB installs that I see are forward firing. Is there a reason for this? Or is it just because it's easier?

After taking some trunk measurements, I can manage to install either way. However, a forward firing design would be a lot easier and much faster to build. A rear deck install is feasible but will require a lot more work. Most of the time consuming work would come from cutting the rear deck for adequate vent area...I was thinking of maybe using a hole saw and strategically 'perforating' rear deck several times over the location of the cones or cutting out a large portion and framing/welding new reinforcement...then fabbing a new vented deck cover, replacing the trunk lid torsion bars with hood struts or similar. Relocating or deleting the 3rd brake light. It all adds up. Sealing the front and rear waves is the easy part. And I fear that cutting too much material out of the rear deck will compromise it’s structural integrity…but I have seen another T-Bird owner install 3 12s in the same car with no reported issues. I don’t mind the extra work if it’s absolutely worth it, as this is my project car...and I'd like to do it once and do it right.

So is one method preferred over the other?

I guess my main question is, would the rear windshield provide any loading benefits? I recently built a pair of horn-loaded (BFM table tuba) subs for my house that are extremely efficient and benefit tremendously from corner-loading in a room. I mean, something like a +6db gain in the lower octaves just from firing them into a corner vs firing into the listening space. I was wondering if the same effect would apply to firing the IB subs through the rear deck, effectively "loading" off of the rear windshield. If so, I still might consider it. Being that this is my first IB install, I'm concerned about having enough output. Yes, this is a SQ based install, but I like it loud and would like to take advantage of any potential "free" output. Each sub will only be receiving 500w via a JL 1000/1.

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[Ridinhi 5,000+ posts]

Tuned in for this....always been interested in IB installs myself

 

[jordon]

I said seal off the cabin from the trunk completely instead of rear deck. Alot simpler.

 

[pickup1 5,000+ posts]

If i had the room...I'd do the rear deck.

Otherwise, trunk works well....you'll like them once they are in.

 

[The Camry]

I have been patiently waiting to install a pair of IDMAX 15s IB since the beginning of winter. Now that the weather is showing signs of cooperating (I'm in the Chicago area), my level of motivation is ever increasing.
This will be my first IB install and I’m having a hard time deciding if I should mount them on the rear deck, firing up towards the rear windshield; or forward firing through the back seats (which are leather and don’t fold down). The vehicle is a highly modified 1997 T-Bird with a large rear windshield that might provide some pseudo-horn-loading benefits, but so many of the IB installs that I see are forward firing. Is there a reason for this? Or is it just because it's easier?The reason is that you dont get any(or you know, not as much) reflections from firing it forward. Its bass directly into the cabin. Firing any other direction, Always gives reflections before it enters the cabin.

After taking some trunk measurements, I can manage to install either way. However, a forward firing design would be a lot easier and much faster to build. A rear deck install is feasible but will require a lot more work. Most of the time consuming work would come from cutting the rear deck for adequate vent area...I was thinking of maybe using a hole saw and strategically 'perforating' rear deck several times over the location of the cones or cutting out a large portion and framing/welding new reinforcement...then fabbing a new vented deck cover, replacing the trunk lid torsion bars with hood struts or similar. Relocating or deleting the 3rd brake light. It all adds up. Sealing the front and rear waves is the easy part. And I fear that cutting too much material out of the rear deck will compromise it’s structural integrity…but I have seen another T-Bird owner install 3 12s in the same car with no reported issuesId be talking to him honestly. he has the most insight into what your need. I don’t mind the extra work if it’s absolutely worth it, as this is my project car...and I'd like to do it once and do it right. Any work is worth it if you love it. This is a hobby. Go full tilt. Logically, id go with the one that takes the less amount of MODIFYING and see if you like it. If you do, Then your golden. If you dont, Do the other way

So is one method preferred over the other?

I guess my main question is, would the rear windshield provide any loading benefits? I recently built a pair of horn-loaded (BFM table tuba) subs for my house that are extremely efficient and benefit tremendously from corner-loading in a room. I mean, something like a +6db gain in the lower octaves just from firing them into a corner vs firing into the listening space. I was wondering if the same effect would apply to firing the IB subs through the rear deck, effectively "loading" off of the rear windshield. If so, I still might consider it. Being that this is my first IB install, I'm concerned about having enough output. Yes, this is a SQ based install, but I like it loud and would like to take advantage of any potential "free" output. Each sub will only be receiving 500w via a JL 1000/1.

Corner loading happens, Reflections also happen. Id try to mount the subs at more of a 45 degree rather than straight at the window but if you did all the work, you could just try them both ways as its a matter of slight mdf attachment.
Most of this hobby is about what works for you because everyone car is different, we can all really only go off of theories. Corner loading is possible, it might sound really great, but all of a sudden it might be causing weird phase issues in midbass. You just never know. Its all about trying and trying and trying some more.

http://forum.e46fanatics.com/showthread.php?t=882071

may give you some ideas.

 

[Ridinhi 5,000+ posts]

I have been patiently waiting to install a pair of IDMAX 15s IB since the beginning of winter. Now that the weather is showing signs of cooperating (I'm in the Chicago area), my level of motivation is ever increasing.
This will be my first IB install and I’m having a hard time deciding if I should mount them on the rear deck, firing up towards the rear windshield; or forward firing through the back seats (which are leather and don’t fold down). The vehicle is a highly modified 1997 T-Bird with a large rear windshield that might provide some pseudo-horn-loading benefits, but so many of the IB installs that I see are forward firing. Is there a reason for this? Or is it just because it's easier?

After taking some trunk measurements, I can manage to install either way. However, a forward firing design would be a lot easier and much faster to build. A rear deck install is feasible but will require a lot more work. Most of the time consuming work would come from cutting the rear deck for adequate vent area...I was thinking of maybe using a hole saw and strategically 'perforating' rear deck several times over the location of the cones or cutting out a large portion and framing/welding new reinforcement...then fabbing a new vented deck cover, replacing the trunk lid torsion bars with hood struts or similar. Relocating or deleting the 3rd brake light. It all adds up. Sealing the front and rear waves is the easy part. And I fear that cutting too much material out of the rear deck will compromise it’s structural integrity…but I have seen another T-Bird owner install 3 12s in the same car with no reported issues. I don’t mind the extra work if it’s absolutely worth it, as this is my project car...and I'd like to do it once and do it right.

So is one method preferred over the other?

I guess my main question is, would the rear windshield provide any loading benefits? I recently built a pair of horn-loaded (BFM table tuba) subs for my house that are extremely efficient and benefit tremendously from corner-loading in a room. I mean, something like a +6db gain in the lower octaves just from firing them into a corner vs firing into the listening space. I was wondering if the same effect would apply to firing the IB subs through the rear deck, effectively "loading" off of the rear windshield. If so, I still might consider it. Being that this is my first IB install, I'm concerned about having enough output. Yes, this is a SQ based install, but I like it loud and would like to take advantage of any potential "free" output. Each sub will only be receiving 500w via a JL 1000/1.

any update on this?

 

[Majik]

Unfortunately, No. These IDMAX 15s are going in my 3rd car, which I'm still gathering all of the gear for. All I really need now are some install accessories (dist blocks, fuse holders etc)...and 60-80 hours of time to land in my lap. I wanted to have the entire system at least functional by June, but that didn't happen. I'm shooting for the end of July now. That should give me at least a few months of play time before I put her in storage for the winter...but I have finalized my design/concept.

I've spoken to a reputable industry veteran, whom suggested to create a baffle that is positioned 6” back from the rear seat and have it open up through the rear deck so the bass can pass through the rear seat and up through the rear deck. Based on this statement, I sketched up the following. The rear deck already has two 6x10" openings directly above the drivers, which vent into the cabin. No cutting the rear deck. No welding...and far less expensive.

Maximizing my cargo space isn't my top priority, although it would be nice to gain more than I've had in the past. Even with this design, it takes up less space than my pair of sealed IDQ 12s; and far less space than if I built a spec sealed box to house a pair of IDMAX 15s.

I kind of wanted the motors to be exposed for a different aesthetic than I've had in all of my past systems, but with this design, that would eat up a lot more cargo space than I'm willing to give up...just to see the magnets when the trunk is open. Oh well. Not a deal breaker. I think it should sound good.

Fingers crossed for my first IB setup and my first pair of 15s. Although I'm not an SPL guy, I can't help but to worry if I will have enough output to satisfy my needs...with only 500w per driver (JL 1000/1). Front stage is a pair of XS69 with 450w (JL 450/4)...excited about these too!

This will give you an idea...kinda like a manifold.

 

[Ridinhi 5,000+ posts]

Unfortunately, No. These IDMAX 15s are going in my 3rd car, which I'm still gathering all of the gear for. All I really need now are some install accessories (dist blocks, fuse holders etc)...and 60-80 hours of time to land in my lap. I wanted to have the entire system at least functional by June, but that didn't happen. I'm shooting for the end of July now. That should give me at least a few months of play time before I put her in storage for the winter...but I have finalized my design/concept.
I've spoken to a reputable industry veteran, whom suggested to create a baffle that is positioned 6” back from the rear seat and have it open up through the rear deck so the bass can pass through the rear seat and up through the rear deck. Based on this statement, I sketched up the following. The rear deck already has two 6x10" openings directly above the drivers, which vent into the cabin. No cutting the rear deck. No welding...and far less expensive.

Maximizing my cargo space isn't my top priority, although it would be nice to gain more than I've had in the past. Even with this design, it takes up less space than my pair of sealed IDQ 12s; and far less space than if I built a spec sealed box to house a pair of IDMAX 15s.

I kind of wanted the motors to be exposed for a different aesthetic than I've had in all of my past systems, but with this design, that would eat up a lot more cargo space than I'm willing to give up...just to see the magnets when the trunk is open. Oh well. Not a deal breaker. I think it should sound good.

Fingers crossed for my first IB setup and my first pair of 15s. Although I'm not an SPL guy, I can't help but to worry if I will have enough output to satisfy my needs...with only 500w per driver (JL 1000/1). Front stage is a pair of XS69 with 450w (JL 450/4)...excited about these too!

This will give you an idea...kinda like a manifold.

cool, always like the idea of infinite baffle. I recently picked up 4 Boston Acoustics G2 10's. I think they are candidates of infinite baffle but not sure. couldn't pass them up for the price. Hoping if I do get to try the IB that they will have good output being they are 10's. Hope running all 4 will make up for cone area.

 

[innsanes 10+ year member]

waiting for my idmax 15 from Majik //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

Had the 12" but that was stolen and now i'm going bigger!