Sealed vs Ported vs Passive Radiator

[jockhater2 10+ year member]

I found this when I searched it. Can someone help me understand it a little better. Basically dumb it down for me. I guess my big question is. Passive radiator vs Ported. What are some pro and cons.

This is what I found when I googled it.
"From another sealed vs ported discussion

The design choice depends on $$$/driver/footprint and power available.

The important differences are .

1. Ported designs need less power to produce output down to their tuning point.
2. Ported designs have better output at their tuning frequency then sealed design when driver/amp are similar.
3. Sealed designs have more output below and above the tuning of a ported design.
4. Sealed designs can inherently protect the driver from over excursion if the box is small enough. Ported designs need a SubSonicFilter to protect the driver.
5. Sealed designs need far greater power to achieve high SPL down low because there is a HUGE boost down low to get output.
6. Audiophile myths like tighter bass are not worthy of any science discussion. Of course a port introduces more noise into the design.



The difference between ported and Passive Radiator is pretty simple.

1. PR allows for a smaller box with same tuning point.
2. PR offers less noise (NO port chuffing, etc).
3. PR costs a little more $$$ vs ported
4. Ported box will have a little higher max SPL vs same amp/driver in a PR design."


@pro\-rabbit ; @double 07 ;
@TaylorFade ; @keep_hope_alive ;

Click to read more...

 

[n8skow 10+ year member]

Those statements all look pretty accurate.

What is your asking exactly?

 

[neo_styles 10+ year member]

Those statements all look pretty accurate.What is your asking exactly?

According to the OP, Basically dumb it down for me. Think he needs the layman's version of what they're trying to say.

 

[n8skow 10+ year member]

...like with pictures and stuff?

//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I tease, I tease...

Sealed - good frequency range, good cone control (e.g. ability to handle power), enclosures can be fairly small.

Ported - basically twice the output at tuning frequency over sealed, sacrificing cone control below tuning (which is where the subsonic filter on your amp comes in - to reduce the signal output from the amp to the woofer below a certain threshold). Downside - quite a bit larger than sealed enclosure.

Passive Radiator - similar properties to ported box without losing enclosure volume to accommodate the displacement of the port (not 'quite' as loud as ported, but louder than sealed, again around tuning). Downside, the extra cost, and trial-and-error of tuning it (by adding or removing weights from the cone).

According to the OP, Basically dumb it down for me. Think he needs the layman's version of what they're trying to say.

 

[neo_styles 10+ year member]

...like with pictures and stuff?//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I guess? I think he just wants a better explanation of why the facts at the beginning are what they are.

 

[n8skow 10+ year member]

*Edited my post above to expand on the 'whats'.

To get into the 'whys' would definitely get more technical than the points he's already covered though - and some of it probably way over my head.

=)

 

[keep_hope_alive Premium Member]

that all seems pretty straight-forward to me...

 

[jockhater2 10+ year member]

...like with pictures and stuff?//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I tease, I tease...

Sealed - good frequency range, good cone control (e.g. ability to handle power), enclosures can be fairly small.

Ported - basically twice the output at tuning frequency over sealed, sacrificing cone control below tuning (which is where the subsonic filter on your amp comes in - to reduce the signal output from the amp to the woofer below a certain threshold). Downside - quite a bit larger than sealed enclosure.

Passive Radiator - similar properties to ported box without losing enclosure volume to accommodate the displacement of the port (not 'quite' as loud as ported, but louder than sealed, again around tuning). Downside, the extra cost, and trial-and-error of tuning it (by adding or removing weights from the cone).

Perfect. Thank you for this.

So a passive radiator set up is a bit difficult to get right? but is basically a best of both worlds minus the output?

Oh. Ok. So that is why you set your subsonic filter. 5 hertz below yours ports tuning correct?

 

[ciaonzo 5,000+ posts]

...like with pictures and stuff?//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I tease, I tease...

Sealed - good frequency range, good cone control (e.g. ability to handle power), enclosures can be fairly small.

Ported - basically twice the output at tuning frequency over sealed, sacrificing cone control below tuning (which is where the subsonic filter on your amp comes in - to reduce the signal output from the amp to the woofer below a certain threshold). Downside - quite a bit larger than sealed enclosure.

Passive Radiator - similar properties to ported box without losing enclosure volume to accommodate the displacement of the port (not 'quite' as loud as ported, but louder than sealed, again around tuning). Downside, the extra cost, and trial-and-error of tuning it (by adding or removing weights from the cone).

Good job.

 

[TaylorFade 10+ year member]

PR's ARE ports. Essentially. They're just huge and use moving mass instead of a volume of air. You actually calculate the weight of the air in a port the size of your PR's diameter to figure out how much mass you need to add. PR's also unload like a bish below tuning so I suggest tuning them lower than you would a standard port if there's a chance you'll play below that.

PR's are kind tricky though. The rule of thumb is at least 1.5-2x cone area or xmax. It's tough to find a PR with double the xmax of our subs, so it's got to be 1.5-2x cone area. Like, a 12" PR for a 10" sub or (2) 10" PR's. Say you use a 12" PR. Well... that's basically a 12" port. Say your 10 needs a 1.5cf box. A 12" port in 1.5 cubes for 30hz needs to be, wait for it.... 218" long. Hello. So... the volume of a 12" port that's 218" long is 14.5 cubic feet. Air weighs ~ .08lbs per cube. .08lbs x 14.5cf is 1.16lbs. That's your moving mass.

Or you can use this "quick" formula...

 

[jockhater2 10+ year member]

PR's ARE ports. Essentially. They're just huge and use moving mass instead of a volume of air. You actually calculate the weight of the air in a port the size of your PR's diameter to figure out how much mass you need to add. PR's also unload like a bish below tuning so I suggest tuning them lower than you would a standard port if there's a chance you'll play below that.
PR's are kind tricky though. The rule of thumb is at least 1.5-2x cone area or xmax. It's tough to find a PR with double the xmax of our subs, so it's got to be 1.5-2x cone area. Like, a 12" PR for a 10" sub or (2) 10" PR's. Say you use a 12" PR. Well... that's basically a 12" port. Say your 10 needs a 1.5cf box. A 12" port in 1.5 cubes for 30hz needs to be, wait for it.... 218" long. Hello. So... the volume of a 12" port that's 218" long is 14.5 cubic feet. Air weighs ~ .08lbs per cube. .08lbs x 14.5cf is 1.16lbs. That's your moving mass.

Or you can use this "quick" formula...

wow. Really good stuff here. Thank you for this. What do you prefer? PR's, ported or sealed? I have only done sealed and ported. I don't know anyone with PR's.

Also. What is unloading?

 

[TaylorFade 10+ year member]

wow. Really good stuff here. Thank you for this. What do you prefer? PR's, ported or sealed? I have only done sealed and ported. I don't know anyone with PR's.
Also. What is unloading?

I love my PR's. Super easy. Cut a hole and drop it in. Done. And they sound great. Ported box output without the hassle.

Unloading is when your subs just flap in the wind like they weren't even in a box. Slap, chuff, slap, chuff, slap, wocka wocka wocka... hello back plate.

 

[TaylorFade 10+ year member]

 

[jockhater2 10+ year member]

Oh wow. Does it save you a lot of box space? How much bigger would your box be if it was ported?

How hard was it for you to get your box to sound right? without the subs unloading.

How much were your PRs?

 

[TaylorFade 10+ year member]

Oh wow. Does it save you a lot of box space? How much bigger would your box be if it was ported?How hard was it for you to get your box to sound right? without the subs unloading.

How much were your PRs?

I think I paid $80/ea. They're custom ones made with the same basket and soft parts as my Tantric MD's. Murph made them for me.

Calculate port volume and wood involved to find the saved space.

Tuning isn't difficult. You can really just do it by "ear" and watching the subs while you play tones. Start super low (like 20hz) and track up until the sub(s) move the least. That's where it's tuned.