Put 3 fingers centered on the cone push it in and out and listen for scratchy sound (speaker not connected) if yes it may be your surrounds. The strips should enter freely or with the same resistance all around, without moving or touching cone.

Yes it makes a slight scratchy noise, and it doesn't when I push it only on one specific side so it's definitely not centered anymore, I think I'll refoam it! Could just age be the reason it's not centered anymore?

Will do! Thanks for your help, I will let you know once it's done if it has solved the problem!

Instead of refoaming, I thought why not just try with the original surround before throwing it away? So I removed the surround from the spider, used some hard photo paper to shim and reglued the surround to the spider frame. It was a lot better after that but still not 100% OK. I then found a spot where I just had to pull a little bit to get the sound good, so while playing some bass-heavy tracks I removed the surround again at that spot and then again glued it while listening if the sound was still OK. I kept pressure on it for some minutes while playing music so I could hear if it had moved a bit. Now it's dried and my speaker once again is sounding great! I could only hear a very slight bit of noise a couple of minutes ago on low volume. I'll see if it holds up, if not I know where the problem is, and can try to fix it better.

Thank you all for your advice and because I know you all love pics, here is one while shimming it!

Nice improvised fix!  Good luck!

Just so we speak the same language, The Basket is the steel frame, The spider is a yellow paper like thingy sitting below the cone and glued to cone and basket. I have changed surrounds on some 15-20 woofers and never had problems. Probably you pulled the surround to one side or other while gluing it. If there are any noises at all, get it right or you will destroy your voice coil.

Oh, ok, thought the spider was the steel frame... English is not my native language and Google translate obviously tranlslates spider to something else 😁

However, the sound I was hearing was caused by the dust cap which I had not yet glued properly, this is also fixed now.

Laurent1602 wrote:

Oh, ok, thought the spider was the steel frame... English is not my native language and Google translate obviously tranlslates spider to something else 😁

However, the sound I was hearing was caused by the dust cap which I had not yet glued properly, this is also fixed now.

Now I like it🙂