Marco, is this the system you have posted with Diesel in the picture? Nice barn! Just kidding.
I would try the simple approach first. Get big pieces of MDF and place them under the speakers. My idea is to spread out the weight of the speakers the floor joists are trying to support. The reason I suggest this is so that you can see if this cheap idea yields any positive results before investing a lot of time and money attacking it in a similar manner.
If the floors are old and creaky, platforms constructed of heavy materials may compromise the safety of the entire loft. Buy one sheet of 4" x 8" 1" thick MDF and cut it in half so you'll have a 4x8 under each speaker. If that doesn't work you might have to try two 4x8s under each.
Try the cheap simple way first! Or get Diesel to curl up in front the creakier of the two speakers.
I would try the simple approach first. Get big pieces of MDF and place them under the speakers. My idea is to spread out the weight of the speakers the floor joists are trying to support. The reason I suggest this is so that you can see if this cheap idea yields any positive results before investing a lot of time and money attacking it in a similar manner.
If the floors are old and creaky, platforms constructed of heavy materials may compromise the safety of the entire loft. Buy one sheet of 4" x 8" 1" thick MDF and cut it in half so you'll have a 4x8 under each speaker. If that doesn't work you might have to try two 4x8s under each.
Try the cheap simple way first! Or get Diesel to curl up in front the creakier of the two speakers.