If you want to tune lower, make the port longer.
That's all there is to it.
Also, the bigger the box, the more output down low as well.

Fusion, dont expect much low end out of your setup, but it should go a pinch deeper than a sealed box, or at least have more meat in the 45-65hz range depending on your tuning.

 

Rockford purposely introduced that concept a number of years ago. They're theory is that someone can start out with an entry woofer and upgrade over time without having to change their enclosure. It was an alright idea.

 

Huh? There is nothing wrong with WinISD (alpha). The person who wrote the program designed it using the same Thiele/Small calculations that every other program uses. I have compared a number of results the program gives with real world measurements and they are bang-on.

Another good program (sheet) is Unibox. Its a bit manual at first but once you find your way around it is very powerful.

Just because you pay a premium price for a program does not make it superior.

Best,
Mark

 

In terms of Qtc calculations, WinISD doesn't seem to have realistic targets for losses (Ql) so Unibox tends to be a touch better for sealed alignments. I haven't really done much comparison between other enclosure types though.

The only real differences between programs is how well the user knows how to use them and what options are available to change. The primary issue with programs like WinISD is that in an effort to make their UI more friendly, some variables are a little more challenging or not as clearly emphasized. When it comes to predicting frequency response, it's really not a complicated issue: user inputs A, computer calculates and outputs B. As Mark indicated, all of the calculations are done utilizing well-defined equations that are very universal.

The only programs that will be radically different (assuming all things constant, which again, is up to the user) will be programs like LEAP or LspCAD that allow you to take boundaries and transfer function into account, in which case the models used for prediction don't quite have the empirical data to back them up yet.

 

Indeed. LspCAD would be the cat's meow if one could afford it. I should expand on my statement a bit - the comparisons I made were based on bass reflex designs, which are inherently more difficult to perfect.

In my experience, determining Ql in sealed designs is erroneous at best, and since the whole concept of sealed box design is so forgiving in nature, one can achieve what WinISD produces without factoring Ql by using good build practices.

Best,
Mark

 

WinISD works..it is close on the tunning
but it lacks a few features for fine tunning an enclosure
I have built well over 1000 enclosures with WinISD,Bassbox pro exc.
and the last 40 or so I have done with Termpak have been
absolutley phenominal...
all due to the ease of the ability to play with the profile score
and the cool port velosity scale
I will never go back to another program