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Port tuning Altec 416 8B cabinets

M

Marheineken

New Member
Hi AKers,

First post here.
I hope someone can help me out or explain me how to measure the correct port depth for my enclosures? I feel that with the current port size I am missing something in the lower end.

I recently build a pair of cabinets for my Altec 416 8b’s based on the Lansing Heritage documents I found on the website.
On top are 802-8g with Emilar eh500 horns.

I settled on an enclosure size of approximately 195 litres (89cm x 59cm x 45cm) somewhere inbetween 612 and 620 cabinet sizes. The port is currently 27cm x 6,5cm and the depth is 18mm, so not ducted.

I did not do any measurements before making the cabinets (as I simple did not know how to). I should have asked this questiion before making the cabinets Iknow.

Now my question would be, by ducting the port would I be able to gain some more bass
/ bottom end? Additionally could someone help me how to tune the port to a lower hz and explain a little more about the process?

Thanks!
Marhein
 
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Hi Rothwell,

Thanks for your reply. Happy to hear that!
Unfortunately i cannot open your link, but I used the original altec 620 cabinets and 416 8b specs as my reference.

Could you perhaps tell me what sonic difference I would notice when my port is tuned to a lower frequency? I am trying to understand this haha.
 
You could mess around with the port and listen for yourself. If you have slot ports on your cabs like the 612/620, just block off part of the port.
 
Tuning the enclosure to a lower frequency rolls off the bass more and makes it behave a bit more like a sealed enclosure. Tuning to a higher frequency puts a slight hump in the bass before roll-off, but since the port is already as shallow as is possible (because it's just the thickness of the cabinet) the only way to get a higher tuning frequency would be to enlarge the port opening.
As elitopus says, reducing the area of the port opening will tune it to a lower frequency.
 
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