Ok let me explain or spell it out for the kid that said I did'nt know what I was talking about. If play a sub, espeacialy in a ported enclosure, with the hatch open or in a SUV with the back up then your sub has NOTHING TO LOAD OFF OF! It causes your sub to have to work much harder, this is even more true when you play at certain fequencies. This is called "SUSPENSION FATIGUE". Will this happen the first time, maybe or maybe not. To play your sub unloaded is not a good idea at all and can very easily damage the suspension of your subwoofer and thats just for starters.Point 2. Common sense should tell you that if you take an amplifier and shake it around alot that you could damage it. An amplifier has many small components inside of it and it only takes one of them comming dis-lodged to cause the amp to not work properly.Do you really think mounting a amp directly on to a sub enclosure is a good idea, you deserve a damaged amp then! Like I stated earlier, does this happen all the time, no it does'nt but it does happen and I've seen it happen more than just a few times in the last 20YEARS I've been around car audio. It's just not the best place to put your amp that you just spent a-lot of money on!!
Ive been in car audio sice a year before you were even born so don't come at me saying what I hav'ent seen before because there is no way for you to know that.
Not too sure if this was directed at me or not, because two of us said you were wrong. But, if it was directed at me, then here we go.
#1 - I am curious how many people have the same viewpoint as you do. There are a large number of people on this forum and others, and people that i know personally, that have their amplifiers mounted to the subwoofer enclosure. The point you are trying to make about damage being done to the amplifier by having it mounted this way is noted, but not very common. I wish i could come up with some real numbers for you, but my guess is that the number of people that have actually damaged equipment this way would be very small. Also, how large of a difference in vibration is there from mounting the amp on the enclosure itself, versus mounting it elsewhere in the trunk/hatch area? My estimate would be minimal. If you place a hand on a surface in your vehicles trunk/hatch area, there is vibration when you have the system turned up even a little. Even in the passenger compartment, there is a large amount of vibration. When a system is really cranked up, it doesn't matter where in the car you are, there is considerable vibration. So, personally, mounting the amp on the enclosure is not dangerous idea, and i would recommend it to anyone who has limited mounting possibilities.
#2 - As to the hatch being open when playing the sub, I ask you to search around the forum for just 5 minutes, and let me know how many videos you find that have people filming with the hatch/trunk lid open. Look also on Realm of Excursion. Unless you have an SUV, there is virtually no other way to video capture the excursion of the subwoofer. What about in an SUV system? A large amount of these systems are setup to have the sub(s) and port(s) facing upward. If you have the doors open in said vehicle, or the windows rolled down, or any type of scenario where the vehicle is not sealed shut, would this not cause "Suspension Fatigue"? In my setup, I spend most of my time playing with the hatch CLOSED and the back seats folded down. I don't go around with the hatch open bangin my system. The hatch was open FOR VIDEO AND PICTURE PURPOSES ONLY!
To summarize, I have been involved in car audio for the better part of ten years. I left it for a while, but not that long. And, in those years, I have never seen an amp get damaged from being mounted on the enclosure. Also, in those years, I have never seen a subwoofer fail due to having the hatch open while filming, or just playing/tuning. So, please, in the future, save your "comments" for one of the newbies on the forum, and don't waste them on someone that already knows that there is a "chance" that things could be damaged. Heck, anyone could go outside and turn their car on in the morning and blow a sub. Crank it a little to hard, poof. There are many scenarios in which equipment could be damaged, but having the hatch open while playing/tuning, or mounting the amp on your enclosure, are not any of them.