passive radiators

[joaquin]

I have a dayton dvc 10" sub and would like to use a passive radiator with it. How many radiators do I need for general bass. One? Two?Is there some rule of thumb I should abide by? THanks!

[Chris Roemer]

> I have a dayton dvc 10" sub and would
> like to use a passive radiator with it. How
> many radiators do I need for general bass.
> One? Two?Is there some rule of thumb I
> should abide by? THanks!

Usually they say you need the capability to move double the volume of air that your woofer can. That means TWO 10" PRs, or 1 12", or one 10" that has twice the Xmax of your woofer. If you don't properly model this, you'll probably be very disappointed.

[joaquin]

> Usually they say you need the capability to
> move double the volume of air that your
> woofer can. That means TWO 10" PRs, or
> 1 12", or one 10" that has twice
> the Xmax of your woofer. If you don't
> properly model this, you'll probably be very
> disappointed.
I have the Dayton SD270-88 10" Shielded DVC Subwoofer which has a claimed linear excursion of 6mm one way. I also purchased the Dayton SD270-PR 10" Passive Radiator which has an Xmax of 10mm. Is that close enough or should I use an additional one? Another question is in what way should orientate the duo?

[philiparcario]

> I have the Dayton SD270-88 10" Shielded
> DVC Subwoofer which has a claimed linear
> excursion of 6mm one way. I also purchased
> the Dayton SD270-PR 10" Passive
> Radiator which has an Xmax of 10mm. Is that
> close enough or should I use an additional
> one? Another question is in what way should
> orientate the duo?
Have the active driver fire forward and the passive radiator on the left or right side. Make the box that if you build with 1 rad on the left you can still put a rad on the right. you might get away with the 1 rad due to the bigger xmax. if not cut another hole and add a second. you need a calculator to know how much weight to add to the radiator.

[Chris Roemer]

> I have the Dayton SD270-88 10" Shielded
> DVC Subwoofer which has a claimed linear
> excursion of 6mm one way. I also purchased
> the Dayton SD270-PR 10" Passive
> Radiator which has an Xmax of 10mm. Is that
> close enough or should I use an additional
> one? Another question is in what way should
> orientate the duo?

I'd give it a shot. I wouldn't mount either one up or down firing, aside from that, it doesn't matter. Mount both on the front (if a taller, narrower cab), one on front and one on back if a cube. The PR WILL be "in phase" (if you tune it properly with mass) so front/back is no problem.

[joaquin]

> I'd give it a shot. I wouldn't mount either
> one up or down firing, aside from that, it
> doesn't matter. Mount both on the front (if
> a taller, narrower cab), one on front and
> one on back if a cube. The PR WILL be
> "in phase" (if you tune it
> properly with mass) so front/back is no
> problem.
What's the general rule with weights on a PR. The active sub doesn't play much below 30Hz but it seems that the PR I that I purchased will "play" down to 19Hz. Also, does P.E. sell these weights?

[philiparcario]

> What's the general rule with weights on a
> PR. The active sub doesn't play much below
> 30Hz but it seems that the PR I that I
> purchased will "play" down to
> 19Hz. Also, does P.E. sell these weights?
there should be a bolt on the radiator 1/4 in or 7mm just add washers and a lock nut. without a program or the ability to measure you can tune it by ear buy some washers and a nylon lock nut at lowes and add or subtract to your liking in bass.

[terryo]

> there should be a bolt on the radiator 1/4
> in or 7mm just add washers and a lock nut.
> without a program or the ability to measure
> you can tune it by ear buy some washers and
> a nylon lock nut at lowes and add or
> subtract to your liking in bass.

IIRC,
If you add a second PR, you'll need to increase the weight on both of them to twice what a single one would use for a specific tuning frequency. Also, the greater the volume of the box the less weight you'll probably need for the same frequency. This is off the top of my head, but goes back to the Original Avatar Audio "Shiva/Passive radiator" combo.
Btw: if you can use a pair, and I believe you should, place them on opposing sides to prevent a tendency for your Sub to "walk."

Best Regards,
TerryO

[alexb]

This site is extremely helpful for subwoofers, especially passive radiators.

<A HREF="http://www.diysubwoofers.org/prd/">http://www.diysubwoofers.org/prd/</A>