WinISD box designing help please

[spaz83]

On 3/27/2018 at 8:01 PM, Triticum Agricolam said:

With cabin gain your response probably will peak around 35 Hz.  

WinISD works very well, you just have to understand it limitations.  The frequency response is shows you IS most likely what you would get if you had that sub out in an open area where it isn't going to be affected by cabin/room gain.  

You can ROUGHLY approximate cabin gain for an average size vehicle in WinISD by adding a filter like this:

Note that when that filter in enable it will totally screw up your cone excursion and port velocity graphs, its really only valid for "Transfer Function Magnitude" and "SPL" graphs. 

Thanks alot man. I have yet tried to find cabin gain yet.. Will do soon. When I find it, is that what I should tune my box to? Thanks for the help. I seriously appreciate it. 

[Triticum Agricolam]

50 minutes ago, spaz83 said:

Thanks alot man. I have yet tried to find cabin gain yet.. Will do soon. When I find it, is that what I should tune my box to? Thanks for the help. I seriously appreciate it. 

Glad I could help!

So cabin gain isn't just one frequency, its a whole range of frequencies.  Depending on the size of your vehicle cabin gain is going to start amplifying your output starting around 60-70 Hz and its going to increase as you go down in frequency from there.  There will be a frequency were cabin gain is the highest, below which the effects of cabin gain will start to diminish.  That frequency where cabin gain is the highest is what is often referred to as the vehicle's "resonate frequency".  That's not exactly the right term for it, but that's what people call it.  Tuning your box to your vehicle's resonate frequency will generally get you the highest output, but that's not always a good thing.  You will probably be sacrificing a lot of low frequency output but tuning high and you will probably get a large spike in the frequency response which may not sound very good.  If you are going for SPL numbers you might be fine with those tradeoffs so tuning to the resonant frequency would be good.  If you want a smooth frequency response, tuning to the resonant frequency of the vehicle is a bad idea. 

[ckeeler11]

For the most output you will want to tune around the resonant frequency of the vehicle. If you are after sound quality you will want to tune so the resonant frequency has the least amount of impact.

[spaz83]

Nice... Thats awesome. I knew the resonant frequency was a range, didnt know when it would start approximately. I thought it was a smaller range than 60ish though. thanks for the advice.