Sub Port or PR

[ben62670]

I will be using an Adcom GFA-555 for my DIY sub with a 15" Dayton Mark III, and 3 12" Polk PR's. A GFA-555 put out 850 watts clean bridged. While this may be a bit much, I also have a GFA-585 to drive 2 subs at 400 watts. We'll see what happens in the real world. First passive project besides SDA-SRS's.
Anyone do anything like this?

Any input from users of both type would be appreciated.
Thanks Ben

[ben62670]

bump

[jakelm]

How big is the encloser? Too small or too big of an encloser I feel will muddy the bass responce and when using 3 12" PR, the resistance has to be perfect or everything would just be "flopping" around.

[heiney9]

Quite an ambitious project. Your enclosure has to be huge to take advantage of that much surface area. Might be overkill to have that many PR's and a 15" woofer.

H9

[ben62670]

The woofer is 15 inches, and has 2 inches of stroke. It calls for a 6 cubic foot cabinet which is roughly 17*17*44. The passive only have about an inch of travel. I know I would have to add a little weight to tune them to 19hz to match the woofer. I was thinking of putting the 3 Pr's in front to match the phase of my SDA-SRS's PR's

[PolkThug]

Sounds like fun! Frequency sweeps will be your friend when trying to dial that thing in.

[ben62670]

My other Idea was to 16" sonotube at 50" with a 4" port on top which would also give me a tune of 19hz.

[ben62670]

Sounds like fun! Frequency sweeps will be your friend when trying to dial that thing in.

Yep a lot of taking the pr's out weighting them and putting them back in.

Here is the woofer
http://www.partsexpress.com/pe/showd...number=295-420

[jakelm]

My other Idea was to 16" sonotube at 50" with a 4" port on top which would also give me a tune of 19hz.

I think this idea will give you better responce than the Pr's

The problem I have is that every Pr encloser I have seen and delt with includes a larger Pr than the driver. I have never seen it done the other way around.

[tryrrthg]

My other Idea was to 16" sonotube at 50" with a 4" port on top which would also give me a tune of 19hz.

You will need 6-8" of port to be able to handle the amount of air that your 15" driver is going to move.

[ben62670]

I think this idea will give you better responce than the Pr's

The problem I have is that every Pr encloser I have seen and delt with includes a larger Pr than the driver. I have never seen it done the other way around.

Yeah I have 3 12"s already, and I used 2 10's with my SDA-SRS project, and it worked good. The thing I like about the smaller pr's is that they respond quicker. It would also look pretty cool with 3 twelves facing forward too. But I am more about performance than looks.

[ben62670]

You will need 6-8" of port to be able to handle the amount of air that your 15" driver is going to move.

I ran WINisd, and a couple other programs, and was recommended by PE to use the 4" flared port. That is another reason I was thinking about PR's. A 4" port with woofer that "15" MKIII will sweep over 3 liters of air! " means an awful lot of port velocity.

[engtaz]

Where did you steal the 585? LOL

engtaz

[ben62670]

Where did you steal the 585? LOL

engtaz

Ebay

[engtaz]

You going to buy me one???? LOL:D :D :D :p

engtaz

[dudeinaroom]

I want one too. If you get bored with the sub project just send it to me(jump on yahoo I'll give you my address) j/k. 3 12" PR's is about right for a 15". You might be able to get away with tuning it lower, and still end up with good results. Man I wish I lived down there, I'd love to be a part of that project, and you'd have an extra hand for fixing the computers at work:)

[ben62670]

I want one too. If you get bored with the sub project just send it to me(jump on yahoo I'll give you my address) j/k. 3 12" PR's is about right for a 15". You might be able to get away with tuning it lower, and still end up with good results. Man I wish I lived down there, I'd love to be a part of that project, and you'd have an extra hand for fixing the computers at work:)

Come on down!

[dudeinaroom]

Not working, so there is no way I have the fundage. I've been looking since the end of January, and there is nothing. I don't have the money to move anywhere so I am kinda stuck. If I had the money I would be there in a second, I'm sick of this cold weather. oh well life goes on.