RL-S in an IB or Aperiodic alignment?

[JonJT 0]

Hey guys.

The unusual T/S parameters and technology in the RL-S woofers have really peaked my interest in them. I've done a bit of research and I'm really considering them for use in car. The high QTS and high FS (especially of the 12 inch version) makes it look like these woofers would start to roll off right around where a cars transfer function would start to kick in. The tiny vas also makes achieving "true" IB easier than some woofers with vas ratings in the hundreds.

Along with IB, I'm considering a sealed alignment because woofer performance wouldn't be affected by whats in my trunk. The problem with this is the box requirements are so huge (as per them T/S parameters) so I was wondering how these woofers would fair in an aperiodic alignment? The theoretical low frequency efficiency of these types of woofers combined with the RL-s's huge linear excursion capabilities and ridiculous BL LINE make it seem that nearly flat FR in a second order alignment or aperiodic would be possible in car without much eq at all. What do you guys think of this? Would the reduced efficiency of an aperiodic alignment be a problem here, especially since the woofers free air efficiency is already really low?

O and if I may, PLEASE provide technical explanations to your recommendations. I'm trying to learn and understand along with piecing a system together.

Thanks!!!!

[DevilDriver 28]

Hey guys.

The unusual T/S parameters and technology in the RL-S woofers have really peaked my interest in them. I've done a bit of research and I'm really considering them for use in car. The high QTS and high FS (especially of the 12 inch version) makes it look like these woofers would start to roll off right around where a cars transfer function would start to kick in. The tiny vas also makes achieving "true" IB easier than some woofers with vas ratings in the hundreds.

Along with IB, I'm considering a sealed alignment because woofer performance wouldn't be affected by whats in my trunk. The problem with this is the box requirements are so huge (as per them T/S parameters) so I was wondering how these woofers would fair in an aperiodic alignment? The theoretical low frequency efficiency of these types of woofers combined with the RL-s's huge linear excursion capabilities and ridiculous BL LINE make it seem that nearly flat FR in a second order alignment or aperiodic would be possible in car without much eq at all. What do you guys think of this? Would the reduced efficiency of an aperiodic alignment be a problem here, especially since the woofers free air efficiency is already really low?

O and if I may, PLEASE provide technical explanations to your recommendations. I'm trying to learn and understand along with piecing a system together.

Thanks!!!!

I don't really have time to model these at work here, but just some theoretical nonsense behind IB. Truely infinite baffle is when system Q (Qtc) is equal to the driver Q (Qts) and system resonance (Fc) is equal to driver resonance (Fs). In all practicality, diminishing returns is achieved once you're 3-5 x Vas.

As far as an aperiodic installation goes, the effects are slim to none at bass frequencies. I'll post up the math on this if I get some time to do so later today.

As far as it's efficiency is concerned, maybe a couple of things worth pointing out. Due to it's long and linear BL, it's moving efficiency is actually fairly high; that is, once the coil is moving, there is no drop in BL and, thus, no drop in efficiency, whereas conventional designs grow increasingly less efficient at the outer limits of it's excursion. Above all, system efficiency reigns supreme: if you're going to be doing a large sealed or infinite baffle enclosure, system efficiency is high and you'll be utilizing the driver to it's best capabilities.

If there is room for such an enclosure in your vehicle, I think you'll be in love with the sonic characteristics of this combination.

[JonJT 0]

Hey guys.

The unusual T/S parameters and technology in the RL-S woofers have really peaked my interest in them. I've done a bit of research and I'm really considering them for use in car. The high QTS and high FS (especially of the 12 inch version) makes it look like these woofers would start to roll off right around where a cars transfer function would start to kick in. The tiny vas also makes achieving "true" IB easier than some woofers with vas ratings in the hundreds.

Along with IB, I'm considering a sealed alignment because woofer performance wouldn't be affected by whats in my trunk. The problem with this is the box requirements are so huge (as per them T/S parameters) so I was wondering how these woofers would fair in an aperiodic alignment? The theoretical low frequency efficiency of these types of woofers combined with the RL-s's huge linear excursion capabilities and ridiculous BL LINE make it seem that nearly flat FR in a second order alignment or aperiodic would be possible in car without much eq at all. What do you guys think of this? Would the reduced efficiency of an aperiodic alignment be a problem here, especially since the woofers free air efficiency is already really low?

O and if I may, PLEASE provide technical explanations to your recommendations. I'm trying to learn and understand along with piecing a system together.

Thanks!!!!

I don't really have time to model these at work here, but just some theoretical nonsense behind IB. Truely infinite baffle is when system Q (Qtc) is equal to the driver Q (Qts) and system resonance (Fc) is equal to driver resonance (Fs). In all practicality, diminishing returns is achieved once you're 3-5 x Vas.

As far as an aperiodic installation goes, the effects are slim to none at bass frequencies. I'll post up the math on this if I get some time to do so later today.

As far as it's efficiency is concerned, maybe a couple of things worth pointing out. Due to it's long and linear BL, it's moving efficiency is actually fairly high; that is, once the coil is moving, there is no drop in BL and, thus, no drop in efficiency, whereas conventional designs grow increasingly less efficient at the outer limits of it's excursion. Above all, system efficiency reigns supreme: if you're going to be doing a large sealed or infinite baffle enclosure, system efficiency is high and you'll be utilizing the driver to it's best capabilities.

If there is room for such an enclosure in your vehicle, I think you'll be in love with the sonic characteristics of this combination.

I have to say that every time I ask a technical question, you're the first one to answer!

I am aware of the characteristics inherent to an IB alignment, and aware that the point of negligible returns is reached at about 3 to 5 times woofer vas. And I also do have the space for an IB enclosure in my car as well. The reason I'm comparing it with an aperiodic alignment is because I don't want my subs characteristics to change as things get loaded into my trunk. When I move off to college, my trunk will be packed with things for my apartment and those 400+ liters of space will have been reduced dramatically. The RL-s 12" is the only woofer out of the two that would be acceptable for use in a second order alignment as the 15" requires too much space. I am hoping aperiodic could provide similar characteristics to that of a true sealed enclosure without all of the space.

Edited July 17, 2007 by JonJT

[///M5 2,833]

You'd have to have a hell of a vent if you went aperiodic, if it were me I'd just deal with the times when the trunk is loaded up with stuff or perhaps just pop it up a little ways and tie her down with bungies.

[JonJT 0]

You'd have to have a hell of a vent if you went aperiodic, if it were me I'd just deal with the times when the trunk is loaded up with stuff or perhaps just pop it up a little ways and tie her down with bungies.

I donno, I still have a while to ponder this so we'll see what happens.