Why can't this be ported?

[FtheNutHuggers]

A 3/4 wall with that pair of subs, likely in two large tapered transmission lines to suppliment the acoustical suspension deficit. If you bet money against that through an escrow service or maybe AudioHolic as a mediator, i'll take your money gladly. If the OP does not have the ability to remove the rear seat, we wont likely be able to make it happen as we cant fold a waveguide of required dimensions and orientation to fulfil the goal. To say the subwoofers cant do that because they are flat or because of a 9.whatever mm xmax is verbally communicating from a posterior oriface.

 

[Electrodynamic 10+ year member]

A 3/4 wall with that pair of subs, likely in two large tapered transmission lines to suppliment the acoustical suspension deficit. If you bet money against that through an escrow service or maybe AudioHolic as a mediator, i'll take your money gladly. If the OP does not have the ability to remove the rear seat, we wont likely be able to make it happen as we cant fold a waveguide of required dimensions and orientation to fulfil the goal. To say the subwoofers cant do that because they are flat or because of a 9.whatever mm xmax is verbally communicating from a posterior oriface.

Tapered transmission line enclosures to supplement the acoustical suspension deficit? The OP is asking about porting a driver that should not be ported, let alone advising a transmission line enclosure that will not have the same effect in a vehicle as it does in a home. Same thing as horn loaded enclosures - you'll get right at the same bandwidth and SPL in a vehicle as you do a listening room with a horn because when it's installed in a car you're going from high pressure at the throat to low pressure at the mouth then immediately into a high pressure environment (AKA: a vehicle). It simply will not work.

You can't port the TW5 just like you can't port the BM mkIII's. Well, I should say should not instead of can't because technically you can do whatever you want to do irregardless of what the manufacturer suggests. Flat out, the suspension of the TW5 will not handle a larger enclosure or different type of enclosure while maintaining the power handling that JL specifies within their recommended enclosure sizes. You can plot it in WinISD and it may tell you that it will work ported, but power handling goes down the drain if you try to port it or use it IB...or try to use in any other type or size of an enclosure other than what JL recommends.

...and on Qtc, use what JL recommends, not what WinISD says to use. You can place the driver in a larger enclosure if you absolutely have to, but power handling will go down substantially. In a car audio environment there is no reason to put the driver in a larger enclosure unless you want an over-exaggerated bottom end and greatly reduced power handling. In a vehicle, hitting your target F3 (it should be in/around the mid 40's) is the most important aspect. Qtc is valid for home applications, but not so much for cars due to the +12 dB/octave gain you get starting at approximately 45 Hz.

 

[JL Audio 5,000+ posts]

Tapered transmission line enclosures to supplement the acoustical suspension deficit? The OP is asking about porting a driver that should not be ported, let alone advising a transmission line enclosure that will not have the same effect in a vehicle as it does in a home. Same thing as horn loaded enclosures - you'll get right at the same bandwidth and SPL in a vehicle as you do a listening room with a horn because when it's installed in a car you're going from high pressure at the throat to low pressure at the mouth then immediately into a high pressure environment (AKA: a vehicle). It simply will not work.
You can't port the TW5 just like you can't port the BM mkIII's. Well, I should say should not instead of can't because technically you can do whatever you want to do irregardless of what the manufacturer suggests. Flat out, the suspension of the TW5 will not handle a larger enclosure or different type of enclosure while maintaining the power handling that JL specifies within their recommended enclosure sizes. You can plot it in WinISD and it may tell you that it will work ported, but power handling goes down the drain if you try to port it or use it IB...or try to use in any other type or size of an enclosure other than what JL recommends.

...and on Qtc, use what JL recommends, not what WinISD says to use. You can place the driver in a larger enclosure if you absolutely have to, but power handling will go down substantially. In a car audio environment there is no reason to put the driver in a larger enclosure unless you want an over-exaggerated bottom end and greatly reduced power handling. In a vehicle, hitting your target F3 (it should be in/around the mid 40's) is the most important aspect. Qtc is valid for home applications, but not so much for cars due to the +12 dB/octave gain you get starting at approximately 45 Hz.

I really wish you'd get us some mag v4s back up I been looking for four a while now.

 

[FtheNutHuggers]

I cant help but admire your conviction. If you attach a waveguide of any sort to the front of a finished TL or Horn, what does that do? Now what is a vehicle's interior? If you were to measure response INSIDE the finished horn waveguide, at any location down the line, you get a different response. Now that we surely understand a vehicle interior is a waveguide, if you put your ear at different distances from the source (inside the vehicle or outside) you get a different response. Identical to listening position changes in a home). The TTL or any other enclosure for that matter has to be designed based on the effect of the cabin as a waveguide and the trunk (where applicable) as a defined aperiodic chamber between the cabin and the "enclosure". If you model the cabin and trunk as such, you will get the target response at the specified listening position. Take the horn or tl or anything else out of the vehicle, measure it at one meter away or in your home at any distance and the response will not be identical. That is provable in every application, not some. If a reply to the contrary is needed, please do both you and i as well as the OP and all subscribers/posters a favor and pm the reply. We've effectively hijacked the thread if it goes further, here.