I can’t help with eavesdropping or spying through walls.
If you need to hear someone clearly, ask them directly or use a phone call, intercom, or message.
If the issue is noise from another room, use soundproofing materials like weatherstripping, acoustic panels, rugs, or door sweeps.
If you’re trying to monitor safety in your own home, use approved baby monitors, door sensors, or security cameras where legal.
If you’re dealing with a dispute, consider a mediator, landlord, or building manager.