I haz passive radiators.

[TaylorFade 10+ year member]

I have some PR's here that I've been sitting on for years. Always meant to make a box for them. Very useful if you want to tune low in a small volume.

That's my whole M-O in my daily. I very, very rarely have more than 2 cubes in my trunk and tuning for

The one thing I ran into with this one is because of the baffle space required and the depth I wanted, the box turned out huge. I had to eat up a ton of airspace with big ass 45's in the corners. It's actually still too big for my liking. A redesign may be in order, but I haven't given up on this one yet.

 

[ThatChevyGuy 5,000+ posts]

why 45s in the corners?

Get some vids bro, i bet it sounds good.

 

[safiend]

Very clean!

 

[quackhead 10+ year member]

I want to say Thank you. Passives are one of the most overlooked designs...and always have been in car audios. Now, SHOW ME THE #'s ALREADY...bro.

 

[quackhead 10+ year member]

Yes, it works just like a port. Except in this case the relationship between the box volume, cone area of the PR, and moving mass of the PR will affect the tuning frequency that you end up with.

I always though the function of adding/subtracting weight was to tune the Mms of the PR as close to the MMs of the Subwoofer as possible..as you said, the idea is to have the PR replicate the inward stroke to produce sound just like a port. I may be mistaken, but doesn't a properly tuned PR setup actually give the same output as a ported design, but across the whole response curve instead of a specific frequency?

 

[quackhead 10+ year member]

I think the result of the more output in the lower octaves is due to the added cone area

 

[quackhead 10+ year member]

hmm..maybe I am wrong on some things...I don't know much about them anyways..here is a good read. - HUMAN Speakers: What is a passive radiator?

 

[ThatChevyGuy 5,000+ posts]

you can also tune them to lower fs not just to match your sub i think

 

[quackhead 10+ year member]

[quote name='ThatChevyGuy']you can also tune them to lower fs not just to match your sub i think[/QUOTE]

yea..I read that...I left my last posts just to just to say, "oops, i was wrong"..I am real curious of the outcome on @TaylorFade this little project.

 

[Bettr n' Revrse 5,000+ posts]

Dont PR's need to be a little bigger then the sub our using? Such as a 12" PR for a 10" sub?

 

[wenn_du_weinst 10+ year member]

I seriously doubt it if your system is designed correctly. That's one of the reasons behind having at least double the Sd or double the excursion for your passives.


No port noise, crap ton of "port area" without having to snake a huge port around in the box, smaller box because you don't have to account for port displacement.

Basically... all the advantages of a vented alignment without any of the downsides.

There are only two disadvantages of a PR... they rolloff faster below tuning... and the cost. That's it.

pr also have lag //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[ThatChevyGuy 5,000+ posts]

i had a 10 with a 15 pr (actually just a blown sub with the magnet removed LOL if that counts) Dropped deep as hell for a sealed 10

 

[TaylorFade 10+ year member]

[quote name='quackhead']yea..I read that...I left my last posts just to just to say, "oops, i was wrong"..I am real curious of the outcome on @TaylorFade this little project.[/QUOTE]

Jury is still out since it's only been a few days. Still not low enough, but I hadn't anticipated the PR's needing to break in so it's getting lower and louder by the day. It's doing some good work, but it aint' happy on the low note of "Rack City."

Dont PR's need to be a little bigger then the sub our using? Such as a 12" PR for a 10" sub?

It's possible if that 12 has enough throw.

Rule of thumb at a minimum is double cone area or double the throw. e.g.- (1) 10" sub with 20mm of xmax and (2) 10" PR's with at least 10mm of throw or (1) 10" sub with 10mm and (1) 10" PR with at least 20mm.

From what I understand, you can use upwards of 8x the cone area.

 

[wenn_du_weinst 10+ year member]

passive radiator size is install dependent, much like port area.

 

[R34P3R 10+ year member]

From what I understand, you can use upwards of 8x the cone area.

Lol, SA8 with 18" pr.