Need "expert" 1803/PR opinions (1 Viewer)

[JimPeitersen]

Guys,
I have been playing with Winsid Pro, and have a few questions about PR's for an BP 1803 box. Perhaps I am misreading the graph, but I don't see were the Styke 18" PR's run into trouble in any reasonable box size (even when I model using only one of them.) Am I missing something? I would like to get some of the 18's that are on preorder, but I am not sure which model and alignment would work the best. Power is not a problem, and I have a BFD. Thanks in advance.
JP

 

[Chris Carswell]

I'm not sure.....
The 18" Pr's have a xmax of 25mm (50mm p-p) with a Sd of 1200 cm^2 = vd of 6L. From what I gather the BP 1803 has a xmax of 25.9mm (51.8mm p-p) and a Sd of 1217 which if my math is correct = vd of 6.3L . With one I think you are cutting it a little close. I'd go with two JTBS .

 

[JimPeitersen]

Chris,
That is what I thought also, but John J. corrected the figures for the 18" models on another thread (and his site.) They have a 3" (75 mm p-p) xmax and can displace about 9 liters. I understand the need for excess excursion, but at what point does adding a second PR become unnecessary?
JP

 

[Dustin B]

Jack G will hopefully jump in soon. But the rule of thumb with PR enclosures is to have at least twice as much Vp as you do Vd. If the 18" PRs are actually 9L of Vp then a pair should be fine with a 6.3L Vd driver, but one would not be ideal.

 

[Jack Gilvey]

I don't post when "experts" are called for, but since my name was mentioned...

If the 18" PRs are actually 9L of Vp then a pair should be fine with a 6.3L Vd driver, but one would not be ideal.

Agreed. If the "newly discovered" 9L Vd is accurate, a pair should be fine. Even if the Vd of one was technically enough (it's not), the shaking caused by such a mass (2500-3000g Mms) on one side without another balancing it would be extreme.

 

[JimPeitersen]

I think it has been mentioned before, but it looks like a simple vented box would be the best choice for this driver. An LT would work also, given the excursion and power handling of the driver. Thanks for the opinions though.
Jack, what PR box do you like for this driver?
JP

 

[Anthony_Gomez]

I agree. If PRs are the route, then dual opposed is the ONLY way to go. This driver ported will use a large enough enclosure such that an 8" port will not be too long.
Take a look at Brian Ownens ported enclosure with the 1803.
http://bkolfo4.freeservers.com/photo.html
I would use the 1803 in a 360L enclosure @ 18hz.

 

[Jack Gilvey]

My conclusion with this driver was that a big vented box made more sense since it needed to be so big anyway...no real advantage to PR's since a nice wide port will fit. I liked 400 liters tuned to 18Hz with an 8"D port.

 

[Anthony_Gomez]

Hey Mr. Expert, who asked you what volume was appropriate

 

[Jack Gilvey]

See what happens?

 

[Dustin B]

Ha, neither of you know what you are talking about :p) I'm the only real psuedo expert here I say it should be 380L tuned to 18.5hz with an 8" port :alien:

 

[JimPeitersen]

You guys are letting this "expert" thing go to your heads. It is actually a fun driver to play around with though.
JP