does anyone now if its ok to put a speaker in the board under the rear seat that will be about 5mm away from touching????????

Its not going to cause problems or catch on fire or anything will it???????

If you get a spark from the speaker and hydrogen evolved from the battery while charging - POP could cause some problems. What if somebody sits on the seat and the speaker is pushed down and contacts the battery posts causing a major short?

What type of car is it?

How would a speaker make a spark? Ive never seen or heard of this before
The speaker will be in the board infront of the battery on a 71 superbug so it wont contact the terminals