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Discussion Starter #1
So I got WinISD and played with a few online calcs as well.

I've got a couple questions regarding these.

First, it seems that when I plug in the T/S specs for a given woofer (HA I6SW in this case), they all seem to give me an undoable small enclosure. Like .03 cubic feet, when the recommended size is .32 vented. I've built the .32 vented and it is small enough, I don't think I can build one a 1/10 the size!

Just for fun I tried the same driver in two different bandpass boxes and kind of got the same thing, really, really small enclosures and the passband was always in the 100-300 range, which is too high I think. I know these very same drivers are running in a bandpass (4th I think) in Scott Buwalda's own car and from those pics, it sure isn't a tiny box.

Second, when looking at winisd plots, I understand the rolloff, peaks, etc. but when I see that for say the given recommended enclosure size (.32ft) and tuned to 38hz, it shows the tuned frequency is like -12db or so. When I tried a bandpass it said the passband was like -40db :eek:

Now, I realize there will be some cabin gain, but 12db (let alone 40) seems like a lot. Am I reading these correctly or am I missing something on the db level that I'm not understanding?
 

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if this is for a 6.5" sub, then those numbers are prolly right. you are not gonna get wild numbers with a sub that small. are you looking at transfer function magnitude or SPL?

also on the box size thing. that is pretty normal. I have not seen it guess the right box size on many installs I have done. just change it to what you need it to be.
 

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if this is for a 6.5" sub, then those numbers are prolly right. you are not gonna get wild numbers with a sub that small. are you looking at transfer function magnitude or SPL
Ah, I was looking a gain. When I look at spl it is a bit more reasonable :)

also on the box size thing. that is pretty normal. I have not seen it guess the right box size on many installs I have done. just change it to what you need it to be.
If I knew what I wanted it to be I wouldn't need the software no?
 

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lol, well no. the software still lets you see what the curves will be before you biuld. especially with ported boxes, it is easy to mess up and cause a huge hump. seeing how it will respond before you biuld is cheaper than biulding tons of boxes, lol.

adjusting box size and port tuning all effect it.
 

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lol, well no. the software still lets you see what the curves will be before you biuld. especially with ported boxes, it is easy to mess up and cause a huge hump. seeing how it will respond before you biuld is cheaper than biulding tons of boxes, lol.

adjusting box size and port tuning all effect it.
I guess what I meant was that if I wanted a baseline enclosure in whatever format (sealed/vented/bp/etc) and I put in the T/S params and the box is just flat out 'wrong' then it kind of makes it difficult to know what to do from there.

Going the other way is easier it seems. Given the same t/s and a given size, show me what it looks like.

part of it is I'm still trying to figure out how to interpret what I'm seeing. Yes I can see that it is 3db down at Xhz and at the frequencies it will actually be playing it will be 8db down, but beyond that I don't know what all I'm looking at.
 

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take a 15" sub and place it in a 1cuft box and tune it to 25hz. you will see what I mean. the response curve will be horrible. once you know what you are looking at, it certainly becomes easier.
 
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