The megaphone project is a freestanding and portable sound and visual installation with flexible, interactive and changeable sound content. A field of red "megaphones" on simple stands recall an iconography of historical sound diffusion and reinforcement, while inviting physical and emotional responses from those who encounter it. To facilitate a distributed and portable full-duplex sound network, we have incorporated PDa (PureDataAnywhere), running on HP hx4700 PDA's and Gumstix computers that are mounted underneath each "megaphone". This enables a stable network of portable devices capable of interlinking the entire field. Each node of this field then has the capability to create a higher level of interactive sophistication, but also sends and receives audio from a central PD patch that stores and re-broadcasts sound inputs across the field, with the option for electro-acoustic realisations related to the immediate acoustic and cultural context.