Complex sentence: Duplex was the trade name name given by Altec Lansing to its line of coaxial loudspeakers, beginning with the first model 601 in 1943, but was most commonly associated with the single most renowned loudspeaker driver made by Altec; the 604.
Split into simpler sentences: Duplex was the trade name name given by Altec Lansing to its line of coaxial loudspeakers, beginning with the first model 601 in 1943. However, the name was most commonly associated with the single most renowned loudspeaker driver made by Altec; the 604.