I work for a small group that rents a few offices from one of those companies that rents out a floor in an office building and then sublets individual rooms. Our group is part of a larger company based in another city. Some of the other renters (our group's peers, in other words) have some very bad speaker-phone habits, and I'd like to find a way to get them to change their behavior.
Several people on this floor think nothing of putting their phones on speaker (at what sounds like max volume) while leaving their doors open. Even with our doors closed, the sound is invasive. Some of them do this for hours per day.
My coworkers and I have talked gently with some of the people individually -- "hey, you probably don't realize this, but I'm three doors down and I can hear every word". We've tried telling them it bothers us, and we've also tried pointing out that their confidential business dealings aren't so confidential. (We've overheard private business discussions like financial plans, and discussions with customers, but so far nothing that has regulatory or legal impact, like health or credit-card data.) We've asked them to close their doors and try to lower the volume on the speaker. Most of them apologize, close the door for the next call they make, and then revert to their original habits. One person told me "well, you guys make noise too, you know", to which I said I was worry that our conversations were bothersome and to please let us know if it happens again.
I have sometimes simply closed their doors, though it feels a little pushy to me when I do that. I have spoken with our landlord (the company that sublets the space to us), and they had a conversation with one tenant once and things got better for a few days before regressing. I also asked the landlord (who provides furnishings and equipment) if they'd consider a different model of phone for their next purchases, one that doesn't go that loud, suggesting that the current phones might have been designed for large conference rooms instead of small offices. (I got a noncommital shrug to that.) I'm not particularly authorized to deal with the landlord -- none of us is -- so on that front we're limited to informal requests unless company higher-ups get involved. I've mentioned the problem casually to my manager (in another city) but he can't do much, and I worry that trying to escalate will come off badly. To someone sitting in an office hundreds of miles away who isn't living it, this must sound pretty petty, right?
We are going to be in this space for about another year. Several of us find headphones uncomfortable so we cannot address the problem only at our end. (We could explore noise-generation; so far people aren't enthusiastic about that.) The space is fully rented out so we cannot shuffle offices. We've done the best we can do in terms of placing people within our space (e.g. putting our conference room, rather than people's desks, closest to the noisiest neighbors). We're not in this space long-term so it's not practical to install soundproofing in the walls; also, since no tenants are in this space long-term, the landlord is not motivated to make improvements.
I'd like to address the problem at its sources, ideally while maintaining civil relations with the neighbors. So I'm looking for a diplomatic solution if possible, or a way to persuade the landlord to take firmer action.
This question is similar, but it asks for what the employee can do at the "receiving" end. I'm looking for ways to tackle the problem at its source. Also, all the "noisy people" questions I could find on the site are about coworkers, with whom there's a shared reporting relationship (if you go high enough); these are neighbors who don't work for our company, so the approaches might be different.
Update: Since posting this question, one of the other tenants complained to the landlord about our direct requests to them. The landlord told us not to talk to the other tenants, no matter how nicely, and to instead let them know when there are problems. Doing that usually fixes the immediate problems and people are getting a little better about closing their doors, but it still happens a lot and the landlord isn't addressing the broader problem (policies, different phones, better acoustic insulation, whatever). The corporate real-estate people are now aware of the problem.