A port Question of a little different nature

[Ritch40]

I have been doing a ton of box modeling of different woofers as of late trying to learn some things. One thing i have noticed on many of the manufacture suggested enclosures, the port velocity on many gets right up there. By up there I mean 100+ ft/sec. Yet in research I have been doing,and continue to do, they say that port velocity should stay below 60ft/sec.

Here is where my questions start on this. Now I do realise that there are many variables that come into play such as cabin, sub positioning, where the box is mounted in the vehicle, and vehicle type among them.

What is a good workable number for this spec as a GENERAL rule?? I know there is no 1 size fits all answer. Does anyone have some solid guide lines on this?

Thank you in advance for any education you folks may be able to offer.

[MrBigs63']

By what i understand your question to be, below 60 is a pretty good number. With an aero you can go slightly higher, and with a very large flare/kerf on a slot port you could go slightly higher. If space permits though you want to keep it under 60.

A lot of guys on here say always keep the number as low as possible. As for me I like to keep the number above 30ft/s. I feel that below that you loose output. One thing you must keep in mind though is that if you ever increase in power or change to a larger xmax woofer, the velocity will go up. So if you build a box right now with a sub on 500 watts that has a 55ft/s port velocity then later upgrade to say 1500 watts on the same sub, you will get a much higher velocity and introduce port noise.

[Ritch40]

When modeling and designing for myself i always factor in max rms power. For the very reason you specified.

thank you for taking the time to read that and answer it. I reall appretiate it!!

[MrBigs63']

No problem sir! Only way to learn is to ask!