Duke: How many "exceptions to the rule" that you describe above do you know of that are being marketed?
Aside from the aspect of roll-off rates, changing the box alignment still doesn't deal with the lack of transient response / out of band port leakage / lack of damping / potential for over-excursion that comes with all vented designs. You simply can NOT take an out of phase signal and use it to reinforce the in-phase signal without multiple drawbacks / repurcussions. With that in mind, it is up to the designer to prioritize which trade-offs are most / least important. When one can avoid most all of these and achieve relatively similar / better results ( except for sensitivity ), there is only one reason to accept the trade-offs that come with vents. That reason would be a lack of available power, which is no longer applicable with modern day designs / technology.
As one tries to achieve greater extension via manipulating the alignment of a vented design, the transient response gets worse. If you want better transient response with a ported design, you have to limit the low frequency extension. Even if you take this approach, the woofer is still unloaded / lacks damping at frequencies below resonance. The fact that you've raised the F3 to obtain improved transient response now exposes the woofer to even greater potential for over-excursion due to having a higher resonant frequency. The higher the resonance, the more potential for woofer overload at frequencies below that point. On top of that, we still have out of band vent leakage to deal with.
One can play all day long with computer simulations, but you can't fight the laws of physics. There are trade-off's involved with every type of design. Rather than try to bend and twist the rules, developing even more problems with increased levels of complexity, why not choose the simplest design with the least amount of trade-offs and work towards optimizing that? It seems that man has a way of making the simplest things in life more difficult than they need to be. Sean
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Aside from the aspect of roll-off rates, changing the box alignment still doesn't deal with the lack of transient response / out of band port leakage / lack of damping / potential for over-excursion that comes with all vented designs. You simply can NOT take an out of phase signal and use it to reinforce the in-phase signal without multiple drawbacks / repurcussions. With that in mind, it is up to the designer to prioritize which trade-offs are most / least important. When one can avoid most all of these and achieve relatively similar / better results ( except for sensitivity ), there is only one reason to accept the trade-offs that come with vents. That reason would be a lack of available power, which is no longer applicable with modern day designs / technology.
As one tries to achieve greater extension via manipulating the alignment of a vented design, the transient response gets worse. If you want better transient response with a ported design, you have to limit the low frequency extension. Even if you take this approach, the woofer is still unloaded / lacks damping at frequencies below resonance. The fact that you've raised the F3 to obtain improved transient response now exposes the woofer to even greater potential for over-excursion due to having a higher resonant frequency. The higher the resonance, the more potential for woofer overload at frequencies below that point. On top of that, we still have out of band vent leakage to deal with.
One can play all day long with computer simulations, but you can't fight the laws of physics. There are trade-off's involved with every type of design. Rather than try to bend and twist the rules, developing even more problems with increased levels of complexity, why not choose the simplest design with the least amount of trade-offs and work towards optimizing that? It seems that man has a way of making the simplest things in life more difficult than they need to be. Sean
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