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Discussion Starter #1
I scored a super insane deal on some BNIB original Alumapro Alchemy 12" subs off of evilbay but was disappointed when I got them in and found out that the seller was selling blemished subs. One of them has about 1/4" sag in the suspension like something was stacked on top of it for a long time, and the surround on the other one looks to have been cut with a knife. Both are still brand new though, and they were so cheap that the shipping to send them back for a refund wouldn't be worth it. These were my #1 favorite SQ sub from back in the day so I am thinking these would be perfect candidates to try my hand at replacing the spiders and surrounds and use them in something.

Here is where I am hesitating - I know the suspension will affect the resonant frequency of the sub, but what I don't know is how much and to what extent. From what little I understand so far, loose = low. These subs have a fs of like 22hz but their suspension feels tight like any regular sub.

What are the variables that I need to take into consideration when I try this out? Are there places I can buy spiders with a similar stiffness? How will I compare the old spider vs. a new one, and how will I know if I have affected the fs of the sub?
 

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Those aren't BNIB and they're basically worthless unless you can find someone to recone them. I'd post really bad feedback and expect a refund without shipping them back. What's the seller going to do with them?
 

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Discussion Starter #3
I appreciate it, but I have already been in touch with the seller and he will only issue a refund if I return them. After the cost of shipping I would only get back like 55 dollars of the original purchase so I don't even feel like bothering with it.

That's not the issue I am posting about, though. I want to turn these into "projects" and get my hands dirty with speaker repair to see what I can come up with. They are absolutely 100% mint except for the blemishes I mentioned so I personally don't think it would warrant a full recone. I am just trying to isolate all of the variables so that I can choose the right spider to replace.
 

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A knife cut surround and sagging suspension is a lot more than just a "blemish". I consider a blemish a cosmetic defect. These are serious mechanical defects.
 

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Discussion Starter #5
Thank you, but I guess I will just look elsewhere for information on the effects spider thickness has on a sub's performance.
 

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Thank you, but I guess I will just look elsewhere for information on the effects spider thickness has on a sub's performance.
I've seen several posts over the past year on this. I'm sure it goes on a sub by sub basis but spider has a large effect. Surround not so much but it has to be air tight. Theres information on here if you search. Also, John at acoustic elegance is great at explaining this type of information.

I'm still a noob but offset will lower usable xmax. In the past I've seen it suggested to mount the sub upside down to bring it back into alighnment over time. Search for spider sag and JBL 15GTi.
 
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