Yes to the first question.
WinISD doesn't account for flared ends, which effectively make the port larger, that's the (main) difference you're seeing.
What second photo?
-
Get an exclusive sneak peek into our new project. >>> Click Here
-
Our native mobile app has a new name: Fora Communities. Learn more.
Quick Precision Speaker Port Question
Hi guys. Just a quick one.
I'm designing a two way bass reflex speaker. For the port, the tuning freq is 55hz, diameter 2 inches and winISD recommends a length of 6.40 inches.
When putting this into Precision port calculator, these are the results I get:
Is this literally just telling me to make the center tube 2.5 inches long and then stick the two flared ports on each end? 2.5 inches seemed small to me, but I guess if with the ports the overall length is 7.5 inches it wont matter? Also does it matter that precision is recommending 7.5inches overall length but winisd is 6.4, or is is so miniscule that it will be inaudible?
Hope everyone's having an amazing bank holiday
All the best
P.s, in the second photo, I don't anyone would know if those resonances would be audible? Thankyou in advance
I'm designing a two way bass reflex speaker. For the port, the tuning freq is 55hz, diameter 2 inches and winISD recommends a length of 6.40 inches.
When putting this into Precision port calculator, these are the results I get:
Is this literally just telling me to make the center tube 2.5 inches long and then stick the two flared ports on each end? 2.5 inches seemed small to me, but I guess if with the ports the overall length is 7.5 inches it wont matter? Also does it matter that precision is recommending 7.5inches overall length but winisd is 6.4, or is is so miniscule that it will be inaudible?
Hope everyone's having an amazing bank holiday
All the best
P.s, in the second photo, I don't anyone would know if those resonances would be audible? Thankyou in advance
1 - 11 of 11 Posts
WinISD doesn't account for flared ends, which effectively make the port larger, that's the (main) difference you're seeing.
Click on the pic and it will open up in another window. If viewing the thread on your phone, just swipe left on the pic.What second photo?
The first 1/2" of the inlet and last 1/2" outlet port flare's don't effectively contribute to the port tuning frequency. It just aids in the reduction of air turbulence. Go with the 7.5" port length.
Ahh, thanks.Click on the pic and it will open up in another window. If viewing the thread on your phone, just swipe left on the pic.
There's my old age getting the better of me again...
So you're saying to have the centre tube at 7.5 inches and add flare onto each end, instead off cutting it down to 2.5?The first 1/2" of the inlet and last 1/2" outlet port flare's don't effectively contribute to the port tuning frequency. It just aids in the reduction of air turbulence. Go with the 7.5" port length.
Kind regards
I just got confused, as a central tube of 2.5 inches seems very small compared to WinISDs recommended 6.4 inches. I know that the overall length would be the central tube and a bit of the flare, but didn't think it would make the center tube that small yet still be an effective port, if that makes any sense hahaYes to the first question.
WinISD doesn't account for flared ends, which effectively make the port larger, that's the (main) difference you're seeing.
What second photo?
Hope you're keeping well
I would follow the Precision Port specs. They went through the trouble of creating that software, and I would assume they did some testing to determine how the flares effect the final tuning. They even list different cutting instructions based on the different port diameters, again leading me to believe they did some testing.
It would be a good idea to cut the tube to their suggested 2.5 inches, but don't glue anything together. Use masking tape. Then test it out and see if you like it. Final tuning usually comes in lower than your model predicted in my experience. You should have a good long piece of tube left over if you need to extend it since you're only using 2.5 inches in your first try.
If you have REW and a mic that would help with your final tuning. Otherwise you'll just have to listen to it and decide if you like it. Maybe build one with the 2.5 inch cut, and the other with a longer tube then compare.
It would be a good idea to cut the tube to their suggested 2.5 inches, but don't glue anything together. Use masking tape. Then test it out and see if you like it. Final tuning usually comes in lower than your model predicted in my experience. You should have a good long piece of tube left over if you need to extend it since you're only using 2.5 inches in your first try.
If you have REW and a mic that would help with your final tuning. Otherwise you'll just have to listen to it and decide if you like it. Maybe build one with the 2.5 inch cut, and the other with a longer tube then compare.
Thankyou!I would follow the Precision Port specs. They went through the trouble of creating that software, and I would assume they did some testing to determine how the flares effect the final tuning. They even list different cutting instructions based on the different port diameters, again leading me to believe they did some testing.
It would be a good idea to cut the tube to their suggested 2.5 inches, but don't glue anything together. Use masking tape. Then test it out and see if you like it. Final tuning usually comes in lower than your model predicted in my experience. You should have a good long piece of tube left over if you need to extend it since you're only using 2.5 inches in your first try.
If you have REW and a mic that would help with your final tuning. Otherwise you'll just have to listen to it and decide if you like it. Maybe build one with the 2.5 inch cut, and the other with a longer tube then compare.
You'll want the overall port length including both flare's to be 7.5". Each 2" port flare is 2.5" long. So 2.5" flare + 2.5" straight center tube + 2.5" flare = 7.5" overall length.
I thought this was the case to begin with, was just suprised how much of the flare was effective so my brain went in over drive haha. Thanks for ur commentYou'll want the overall port length including both flare's to be 7.5". Each 2" port flare is 2.5" long. So 2.5" flare + 2.5" straight center tube + 2.5" flare = 7.5" overall length.
appreciated1 - 11 of 11 Posts
- This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
AVS Forum
A forum community dedicated to home theater owners and enthusiasts. Come join the discussion about home audio/video, TVs, projectors, screens, receivers, speakers, projects, DIY’s, product reviews, accessories, classifieds, and more!
Full Forum Listing
Top Contributors this Month
View All
WilliamR
872 Replies
BASSAHOLIC
487 Replies
mrtickleuk
402 Replies
Recommended Communities
