Ported vs. PR for my application

[gckless 5,000+ posts]

So, thinking about doing PSI PR's with my 3HP's. I know I have seen that rule of thumb is have double the Vd in your PR's as you do in your powered drivers, but how much wiggle room is there? Can I get away with less? And there's no problem with doing different sized PR's in the same box, right? From what I understand, I just need to make sure each weighs what it should based on the tuning I want.

I'm also looking for info on ported vs. PR in the sound arena (I understand the immediate positive of space savings). How do they sound different? What stuck in my head when I was reading was "the sound of a sealed box, with the output of a ported box." I know this can't be entirely true. Was looking to see how they act at low/high tuning under power. I read they roll off at 28dB (PR) vs. 24dB (ported) under tuning.

So here is my ported box design:



Two 15" 3HP's run off a DC 5k. This box is tuned just under 30Hz. Would probably tune around 27Hz or lower with PR's. Most amount of Sd I could fit here is a 15" and two 12" PR's, but not sure that would be enough.

Reason I'm thinking about this, is that I'm trying for a great sounding decently loud setup, but the focus is on sounding good.

@TaylorFade I know you've played with PR's, what you got for me? @ciaonzo @keep_hope_alive

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[ciaonzo 5,000+ posts]

You can definitely make a vented or PR setup sound like sealed but with far more output. As loud as the same driver tuned to some feggish high midbass tuning? No, lol. But certainly much more than the same driver in a sealed design (provided the driver was suited for both sealed and vented in the first place). I will work on some models for comparison and make some points on this. Might not get around to it tonight or this weekend. It's my birfday!

As far as PR area, it's all about how loud you intend to get. You can use 1:1 but you will lock up if you try to dump tons of power into the driver. Example, if you had an EPIC 12" and wanted to use a single 12" TC VMP, you would be fine because the VMP has for more excursion capability than the EPIC12". I wouldn't suggest the same for the AXIS 12", I would use a minimum of a single 15" VMP or two 12" VMP's. For you, because I thik you intend to get decently loud, I would go 2:1.

So can you fit six 15" cones in your ride? lol

 

[gckless 5,000+ posts]

You can definitely make a vented or PR setup sound like sealed but with far more output. As loud as the same driver tuned to some feggish high midbass tuning? No, lol. But certainly much more than the same driver in a sealed design (provided the driver was suited for both sealed and vented in the first place). I will work on some models for comparison and make some points on this. Might not get around to it tonight or this weekend. It's my birfday!
As far as PR area, it's all about how loud you intend to get. You can use 1:1 but you will lock up if you try to dump tons of power into the driver. Example, if you had an EPIC 12" and wanted to use a single 12" TC VMP, you would be fine because the VMP has for more excursion capability than the EPIC12". I wouldn't suggest the same for the AXIS 12", I would use a minimum of a single 15" VMP or two 12" VMP's. For you, because I thik you intend to get decently loud, I would go 2:1.

So can you fit six 15" cones in your ride? lol

Happy Birthday bro! Take your time with the models. Lookin forward to them though.

And yeah, what you explained about the excursion/surface area is what I had understood. At lower volumes/power levels it's not as important, but once you get into bigger setups, double the Vd in the PR's is rule of thumb. I do plan on getting pretty loud (Two 3HP's off a DC 5k), so I was pretty much thinking I would, but hoping I wouldn't, need more PR than I can fit //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[mat3833 10+ year member]

ive played with PR's a bit in HT enclosures. the best ratio i have found(in general, and keep in mind this is HT) is step up one size and go for more excursion. so if you have an 8" sub use a 10 PR with at least the same or higher excursion. in your situation it might be hard to get enough cone area and excursion for a PR settup to really shine.

the best PR settup i ever did was for a friend. he has a Epic 10 and wanted to be able to "bring the house down" ended up using 2 10" PRs with 1.5X the excursion, and tuned them to 20hz(tuned being a loosely defining word. more like weighted them, lol). i may not be good at theory or explaining things, but when given the resources i can make magic. lol

Matt

 

[ciaonzo 5,000+ posts]

Happy Birthday bro! Take your time with the models. Lookin forward to them though.
And yeah, what you explained about the excursion/surface area is what I had understood. At lower volumes/power levels it's not as important, but once you get into bigger setups, double the Vd in the PR's is rule of thumb. I do plan on getting pretty loud (Two 3HP's off a DC 5k), so I was pretty much thinking I would, but hoping I wouldn't, need more PR than I can fit //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

Thanks, man. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Might want to stick with a huuuuuuge vent, lol.

 

[gckless 5,000+ posts]

ive played with PR's a bit in HT enclosures. the best ratio i have found(in general, and keep in mind this is HT) is step up one size and go for more excursion. so if you have an 8" sub use a 10 PR with at least the same or higher excursion. in your situation it might be hard to get enough cone area and excursion for a PR settup to really shine.
the best PR settup i ever did was for a friend. he has a Epic 10 and wanted to be able to "bring the house down" ended up using 2 10" PRs with 1.5X the excursion, and tuned them to 20hz(tuned being a loosely defining word. more like weighted them, lol). i may not be good at theory or explaining things, but when given the resources i can make magic. lol

Matt

Yeah, that's what I meant by double the Vd. Vd is volume displaced, which is surface area (Sd) multiplied by Xmax. Don't mean to patronize you, just clarifying. Unfortunately I don't have the space to fit twice the amount. So at this point I guess I'm looking for deeper information than people typically get. Or experiences, so thanks man!

 

[mat3833 10+ year member]

Yeah, that's what I meant by double the Vd. Vd is volume displaced, which is surface area (Sd) multiplied by Xmax. Don't mean to patronize you, just clarifying. Unfortunately I don't have the space to fit twice the amount. So at this point I guess I'm looking for deeper information than people typically get. Or experiences, so thanks man!

not a problem. IF you can find really high excursion PR's you should be able to get away with 3 12" PRs. you would have ~the same(slightly more depending) "cone" area, but if you can get 1.5X or more excursion you should be ok.

Matt

 

[jockhater2 10+ year member]

Thanks, man. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Might want to stick with a huuuuuuge vent, lol.

Happy Birthday shane!

 

[ciaonzo 5,000+ posts]

Happy Birthday shane!

Thanks, guys! //content.invisioncic.com/y282845/emoticons/toast.gif.bc0657bf54b9ee653b6438524461341e.gif

 

[gckless 5,000+ posts]

Thanks, man. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Might want to stick with a huuuuuuge vent, lol.

Yeah the box design I showed above has a pretty large port. Wanted to tune lower, but this was the lowest I could go due to space.

not a problem. IF you can find really high excursion PR's you should be able to get away with 3 12" PRs. you would have ~the same(slightly more depending) "cone" area, but if you can get 1.5X or more excursion you should be ok.
Matt

Yeah, in my first post I said that I could fit one 15" and two 12" PR's. Would give me a bit more surface area than my two 15" powered drivers, but not sure about double the Xmax. The PSI PR's have about 3" usable Xmax according to their site, so it might be alright.

 

[mat3833 10+ year member]

ive never tried using different sized PRs, would be a first. lol

Matt

 

[ciaonzo 5,000+ posts]

Bro, with your cone area, excursion, and power...I would have gone medium sealed and EQ'd the low end to taste. You would easily be in the 'teens for extension.

I once had a single 10" LMS on 900w and with a little EQ bump at 20hz it absolutely murdered everything from 40hz to 15hz.

 

[gckless 5,000+ posts]

Bro, with your cone area, excursion, and power...I would have gone medium sealed and EQ'd the low end to taste. You would easily be in the 'teens for extension.
I once had a single 10" LMS on 900w and with a little EQ bump at 20hz it absolutely murdered everything from 40hz to 15hz.

Damn, more to think about! Sure would help the low end extension. Guess I'm just trying to wring all the output I can out of these beasts. But, maybe that is the way I should go.

 

[gckless 5,000+ posts]

Bro, with your cone area, excursion, and power...I would have gone medium sealed and EQ'd the low end to taste. You would easily be in the 'teens for extension.
I once had a single 10" LMS on 900w and with a little EQ bump at 20hz it absolutely murdered everything from 40hz to 15hz.

Here's T/S:



Think they would do better in sealed or ported? From what I can gather, they would do decent in either.

 

[hispls 5,000+ posts]

You can't get a pair of 18" PR's on that box?

I expect when the new Sundown cones/spiders/frames come out those would make a good platform for super excursion PR, at the moment I'm not sure what'll have more throw than Ti basket with 10" spider to do 1:1 area and get away with throwing that kind of power at them.

Also if your goal is music you can probably get away with a bit less port area especially with flared ends if you're trying to get tuning down.