Aren't passive radiators out of phase?

Besides the phase considerations, you should look at the transient response of all vented designs. Passive radiators are the slowest of the slow but can still sound "good" if done right. I much prefer a well tuned passive radiator to that of a port for multiple reasons. Sean
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I've never spent much time playing with or learning about passive's although i have owned a pair or two over the years. As you probably know from some of my posts, i am a "sealed" kinda guy when it comes to boxes with TL's coming in second. Someone that is far more knowledgable in this area would have to help you out.

All i can say is that passive's allow a lower percentage of "out of phase" signal to play with speakers reproduction above its point of resonance than what a port or simple "slot loading" allows. Below the point of resonance, they are all about equal. Sean
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Mish, your HT sub sounds like a different yet probably more "technically correct" approach to using passive's than how most other designs go about it. What brand and model of sub is this ? Such a design doesn't ring any bells to me.

As to your "music" sub, have you ever thought about adding another driver in a push-pull or isobarik / compound arrangement ? Either of these can increase apparent box volume, lower FS, increase transient capabilities, lower distortion, etc... Only drawbacks to such designs is the lower impedance.

Is your music sub with the 18" a single or dual VC ( voice coil ) ? Sean
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PS... Sorry for getting off topic but it's not often that you get someone with BIG subs like that on a thread like this. Especially of such dis-similar designs : )

Ports, slots or any other type of bass reflex design with a "hole" in it allow out of phase information to leak out of the box. The output from the port that is "in phase" is only very near the region of tuning. Stuffed transmission lines also do this, but the output level is drastically reduced. Passive's do not suffer this problem since there is no "leakage" from the backwave of the drivers BUT passive's can contribute lower levels of output at frequencies other than their point of resonance. EVERY design has some trade-offs to them. Sean
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