Protip: Using a sub? Plug your mains

Hey @testpilot - So main speakers have their own natural rolloff and that a lot of audiophiles forego the use of, or can’t, put an electronic high pass filter in line with the main amplifier. As a result, the main speakers go pretty low and the bass can get messy. By plugging the port you raise the -3 dB point, letting the sub handle more bass.

The critical thing, for me is this: By plugging the ports you prevent excessive excursion below the port frequency, hopefully reducing distortion. This benefit exists whether or not you use an electronic high pass filter.

If you are using an electronic high pass filter this becomes less of an issue.  I'm doing a project soon I hope to better document why this work.  Stay tuned.  I have lots of solder and breadboards to go through. :)

Makes perfect sense to me. The driver ends up operating more in line within its capabilities, reducing heat and distortion. Every little bit helps.

All the best,
Nonoise

It seems the high pass filter should be enough.  I have read that plugging ports can mess with the speaker performance intended by the designer.  Could plugging the ports affect frequencies above the intended level at which the mains cross over to the subs?  I guess the only way to know is to try it.  In my system, I believe adding a HPF (Marchand XM446XLR) improved SQ when playing the system at higher volumes, but I do not perceive any difference at low-mid playback volumes.  My current speakers are not ported so I cannot comment on the effect of both a HPF and plugging the ports.

It seems the high pass filter should be enough.  I have read that plugging ports can mess with the speaker performance intended by the designer.  Could plugging the ports affect frequencies above the intended level at which the mains cross over to the subs?  I guess the only way to know is to try it. 

@mitch - It is true that you can't just willy nilly pick to port or not, and the size of a cabinet to ensure optimal performance. In terms of the overall frequency response, you are only changing the lower part of the woofer's response.  The upper part is dominated by other factors.  The big benefit is reduction in distortion by minimizing excursion, an especially important thing in 2-way designs as it can affect the clarity of the midrange a great deal.

The other big benefit is ths woofer will distort less at higher output.

A line level crossover, when significantly higer than the port tuning frequency, should be enough. :)

@erik_squires How does plugging the port keep the amp from trying to play down low? I don't have any high or low pass filters in my system. I want to try your suggestion but can you explain why physically plugging the port will change the amp's output? I realize it will change the outcome, but why would it change the out put?