Hello all. I have started the process of trying to figure out my subwoofer situation. Reading forums and trying to get advice from anyone that would give it to me, I have come to the conclusion that I will need to design the enclosures myself. Now, as I have stated throughout this build thread, I am no expert in speaker design so I will be very grateful for any help that can be provided.
To refresh memories, I will be using the Infinity Reference 1262W to build 2 subs for my HT. My plan is to build ported boxes. I don’t know at this point what type of ports I want to use (open to advice). I like the style of the dual ports below the subwoofer and I also like the style of the long slotted port at the bottom of the box.
I have been told my several people that I will need a 4.0 cu ft box. I’m not sure if it should be a cube shape, rectangle shape or just whatever dimensions that fit my application. I don’t have the theater finished yet so I don’t know exactly what dimensions I’ll need but it looks like I could potentially do a 20-21” cube and be ok to stay under my projector screen.
Now, what I am going to need help with first is understanding what the graphs that WinISD spits out mean. I understand to a certain degree but additional help would be appreciated. I’m sure this will also help when I start to measure my speakers performance later on. I plugged the driver parameters into the program and these are the charts I got. Didn’t do anything but plug in my driver numbers and 300W. What I need to understand about each chart is: 1) Are these numbers good for my application and box type? 2) How will the numbers affect the sound quality? 3) If the numbers are bad, how do I correct them (box volume, port dimensions, etc..)?
First, the parameters. Notice that I said a 4 cu ft box was recommended but WinISD shows a 5.3 cu ft box with the driver parameters:
Now, the charts. Starting with transfer function magnitude:
And rear port air velocity:
As mentioned, advice on anything above will be greatly appreciated. Also, I have been playing around in Google Sketchup so I can design the box once I have dimensions. I put together the Sten II's that I'm building for my surrounds in there and they look pretty good so I think it will come out well.
MattEdited by mathu126 - 7/27/12 at 3:33am