Click here to purchase the entire book in PDF format. Disadvantages You can't make it very large, or have a very large excursion (it'll break apart) so it's not good for low frequencies or high sound pressure levels. The magnets have to produce a very strong magnetic field (making them very heavy) because the ribbon can't. The impedance of the driver is very low (because it's just a piece of aluminum) - so it may be a nasty load for your amplifier, unless you look after this using a transformer.