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SpeakerBoy

Passive Radiator tuning calculation

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I'm having trouble getting the right mass to tune a PR enclosure

 I got ~1200 grams when I used a calculator online but 158 grams when I used the mass of the air in the port as my starting point. I feel like i'm missing something.

i'm aiming for 8cu @ 26hz with a single 18" and two 18" PR's

What do I need to do to get the correct calculation? The reading seems straightforward but I keep getting these two opposing answers. 

 

Thanks, 

          -Chris

 

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Perhaps you should share what you are using.  Obviously something is drastically wrong...

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(2) PSI 18" PR's and my BTL18. As soon as I figure out how to calculate the tuning I'm ordering the PR's. I figure I can just add mass til it sounds right but I kinda wanna know what's going on.

 

WinISD says 650g (not sure if that's each or total) and has a curve I think fits what I'm looking for, don't know how to factor in cabin gain in relation to the graph but it slopes down til about 35 then rises back up til 26hz where it begins to drop off. Mid 20's is what I want to emphasize with less pronounced upper 30's-40's. I just want some trunk back, not to mention it looks sexy.

I can upload the winisd plot if it means anything.

 

I've heard rumors Fi makes PR's? Only going with the PSI's because they were easy to find, not too expensive, and I can get blank dustcaps. They seem beefy enough for this build.

Edited by SpeakerBoy

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Don't you have vance dickasons book?  I remember you buying it I thought.  Always best in a first design to calculate by hand.  

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No, that's definitely still on the list of things to buy.

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How much weight did you end up using on each of your pr's

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On 3/8/2017 at 7:55 PM, Ernestgary said:

How much weight did you end up using on each of your pr's

Sorry, missed this in the recents list. 

I honestly don't know for sure, I never measured it. It ended up using a two or two and a half inch long 3/8" bolt and about eight or ten 3/8" washers. 

It doesn't really matter because I just added weight until I achieved the desired tuning. 

IMG_0027.JPG

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5 hours ago, altoncustomtech said:

It doesn't really matter because I just added weight until I achieved the desired tuning. 

...which is your end goal :)

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