in a nutshell, OP-4 is four tiny OP-1 synthesizers stacked on a rack to look like a proper modular system, when it's not really. i then control them using virtual modular software i wrote, a bit like a real modular. this has proved to be a very flexible way to compose and produce interesting sounds and textures. Teenage Engineering TX-6 mixer: Performance and verdict. This digital mixer offers a lot under-the-hood too. There are channel effects, with a three-band EQ, a compressor, bi-directional filter and a gain control. These are joined by a pair of master effects, one set up as a send, the second as an insert that can either be placed on one mixer. Teenage Engineering OB-4 - The Future of Synths. Watch on. Is the Teenage Engineering OB-4 Magic Radio 'the future of synths'? According to Betteridge's Law of Headlines, the answer to this rhetorical question must be 'No'. Nevertheless, that's the question raised by synthesist Leo Mendez in his latest Synths with Leo video. Teenage Engineering is such a cool, innovative company that make incredibly high-quality and unique instruments. I own 2 pocket operators that have a permanent home on my desk, and that I use regularly when I need to take a break from working. Their products are powerful, intuitive, and well-made. My OP-1 is one of the most fun things I own.