My sitting place is not as quiet as I wish (neighbors talk). Aside moving, what can I do?

As I suspect, a remedy would be playing some noise in my headphones, but I am not sure which would harm the quality of meditation and which would be neutral. Do you know which does what?
Another solution would be the noise cancelling headphones. Did you try? Does they work?

I meditate at the gym mostly, have for years now. There are weights clanging, people talking, music blaring, sound of running on the treadmills, grunts and wheezing, etc. I no longer have an issue with the loud noises for insight practise. Perhaps you can get used to whatever is going on and use it to help meditation rather than hinder it. Just a thought...

If your trying to do concentration, sometimes quiet can be helpful.
I used this - http://gnaural.sourceforge.net/  in the past to listen to binaural beats before first path. I think it might have helped me at that time....

Good luck,
~D

Hi man , you can use earplugs(helped for me).

Just some thoughts from a relative noob.
I follow TMI (Culadusa) approach, where your mission is to focus on the object of your intention, but in paralell you want to have a clear awareness of what is happening around you ( In your body, noices, cold/warm winds, tremors, thoughs etc). I was sensitive to noice before, now noise does not bother me much. If anything appreciate it because it will take your focus away from your intention, and every time you regain that sense of having lost the focus you are able to be happy about that and revert. 

I figure it is tougher to get to high concentration states in such surcumstances, however once you get there you will have way more resilience than a practitioner that require total stillness.

Just my 2 cents
cheers.

I have some fully padded headphones designed for ear protection at shooting ranges. I can still hear background voices while wearing them, but they are muted enough to make it hard to pick out words; thus, the brain finds it easier to give up trying. Phones with some noise might work well. If you search for "pink noise" you will find some interesting info. I would not use audio intended for brain-wave modulation.

soft wax earplugs in addition to the earmuffs helped me get a noticable improvement over the shooting muffs alone.

etymotic musician's earplugs.

If they are loud at night, go over and demand that they be quiet.  They have no right to disturb the neighbourhood.