Mac tube equipment was voiced with Altec Lansing speakers during the 60's and 70's. Many of the speakers were high efficency speakers running 16ohms or 8ohms.A common model used was Voice of the Theatre A7-500, which had a large sectional horn 511b and a 15" bass woofer w/crossovers @500hz. The sound from the Mac tube equipment was quite good for its day, and is likely a satisfying match today. James B Lansing was the chief design engineer for Altec, he had a falling out with Altec Corp. in the late 60's and started his own company JBL (his initals). The design of JBL is similar to the older Altecs and would match the original voicing intended by McIntosh.