The low walls were a blessing and a bane. My team worked well like that. None of us are particularly loud people. We all had headphones and quiet music. The flow of the pen allowed easy communication and rolling between each others cubes.
The bane came from other teams around us. There was a woman that was going through an extremely messy divorce (attempted murder of herself and children by arson). She was understandably upset. Rather than taking family medical leave she would talk to her mother for hours in her cube. Her voice was particularly grating to me. I ended up leaving one day to buy a pair of firing range headphones and firing range earplugs.
Sadly the headphone/earplugs only sort of worked. They're designed to reduce low noises like a gunshot. Her voice was higher. They did help. I was able to concentrate.