[John Williamson]

On 19/06/2017 11:25, wrote:
Trevor wrote: "On 18/06/2017 7:40 PM, gray_wolf wrote:
I was browsing some old JBL vintage sites and I noticed they had a
number of 32 ohm speakers available way back when.

Yes, I think they were aimed specifically at the theatre sound market to
reduce cable losses. JBL and Altec being major players in that market.

Trevor. "

The That's another thing I don't get.
HOW does a HIGH-impedance speaker
"reduce cable losses" in long runs like
in a movie theatre?? I'd think you'd want
efficient, low impedance speakers in
a huge space like that.

Again, you prove your almost complete lack of knowledge. The lower the
speaker impedance, the higher the drive current for a given power, and
the more power you lose in the speaker cables, which can be calculated
by using Ohm's law.

Also, speaker efficiency has very little connection to speaker impedance
in any case, and in cinemas, the main control over efficiency is the way
the drive unit is acoustically coupled and matched to the horn.

The alternative is to make the speaker cables *much* heavier, which
costs a fortune on long runs. The technology at the time did not permit
the amplifiers to be located behind the screen with the speakers, and
the alternative of using 100 volt line amplifiers and transformers to
match the speakers to the line is inefficient and is not good for audio
quality.

--
Tciao for Now!

John.