<human>: Here is my new dilemma, I am hoping you kind people can help me rectify it.

Basically I am in an apartment that's like little 2 story houses that are all stuck together with a wall between each apartment. 

The previous tenants next door never complained about my noise and I therefore thought I was ok. 

So yesterday, I am playing the Mass Effect 3 demo and getting into it, and it is quite exciting, and the volume, crept up.

So, at 3pm in the afternoon I get a knock at the door, it's the neighbor's wife/gf saying that they have a baby and I am being too noisy.

Unfortunately I was a complete douche about this and said "but it's the middle of the day, I don't think I'm doing anything wrong". I then whined about working all week and I get so little time to myself and I just want to play my game but will turn it down.

I shamed myself basically and wasn't very neighborly at all. 

Anyway, I had a dummy-spit and turned off the game and then turned on some Trance Around the World so that I could vacuum. 

Now, I set the volume on TATW so that it wasn't louder than the vacuum cleaner, because, I figure it's within my rights to be able to clean my apartment (which I do every Sunday).

Anyway, thinking I was in the clear at exactly midnight last night the new neighbors decided to extract revenge by, I think, putting a subwoofer against the wall and vibrating it. I could barely hear a beat, it was just a big vibration.

Now, I just put some cotton wool in my ears and went to sleep no problem, but that's not the point.

Clearly I have upset them, and I was not a polite, decent person when they asked me to turn it down, so, can Reddit help me in figuring out what to do to diffuse the situation?

Do, I knock and humbly apologize, stick a letter in their mailbox? Do I mention that I heard their "revenge attack" or ask them if my noise has been better.

Should I buy them some kind of food gift?

Can you condense the text into three sentences or less?
<bot>: Having a bit of a noise war with the neighbors, I was a douche when they asked me to turn my stuff down and now I want to make amends, looking for advice as to how to do this.