Sub selection and WinISD

Ok, so I've read here the tutorial on WinISD by stevdart. I tried to use it before, but now I actually understand what I'm doing and it's actually fun...and addicting too, lol... Anyways, I'm in process of looking for a new sub for my next system. SQ is my primary concern, 1 sub in a sealed box, around 600 wrms, 12 inch. Diamond Audio D612 D4 was on the top of my list, but thanks to WinISD now it's scratched...I guess. It recommends a vented box for it, and putting it in a sealed box gave me this, along with 2 other candidates: I've been trying many brands today and these are the best so far..for my price range. Diamond seems to cut off at 56hz, which seems very low, but we already know that it's not suited for a sealed box. CDT is nice, but the box size is too huge, and it is also only 300 wrms. The Infinity looks very good, the box is large too, but not over the limit. It peaks a bit over the red line, but this can be adjusted with an eq... These are my observations from what I could understand by looking at this graph and some specs. Does anyone else has anything to say about it? Is that Diamond surely out of the picture? Are there other subs I should plot and consider? Thanks in advance.

Glad you're seeing how to use WinISD. I have a few comments. First, I wouldn't care about the bump "over the red line." That red line doesn't mean anything and any bump under 1db you can't even hear anyway. Second, you don't need to strictly adhere to a Qtc of ~.707. In fact, many people like a slightly higher 0.8-0.9 for car audio. This also helps obtain a smaller enclosure size. Third, the Diamond's response is actually pretty typical for "small box" woofers. -3db at 56hz would be bad for a home audio system, but isn't necessarily bad for car audio. Cabin gain in most cars will give quite a lift below 50hz. This is impossible for WinISD to model. Fourth, subjective quality is impossible for WinISD to model. Finally, you need to decide whether you're willing to give up the trunk space of the other two woofers. That extra low bass response comes at a price. Additionally, you have the hang of it. If you're into very deep response, the Infinity is probably the way to go. They have nice sound quality too, an added bonus. (Have you tried modeling an Adire 12D2? I think you'll see it models very well for car audio in a reasonably sized box (use qtc=0.8). New Project: 2003 Pathfinder