Re: The joy of FORTRAN

On 2025-03-12, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 12/03/2025 19:56, Charlie Gibbs wrote:

Building a good studio monitor takes money and skill and people
are not prepared to pay for that and nor do they actually notice
the difference anyway.  Especially on rock music

Even worse, the last thing most of them want is the good clean
sound a monitor will give you.  They want lots of boom - so many
PAs are set up with a huge broad peak centered at about 250 Hz.
It sounds like crap, but everybody seems to want it that way.

>
In terms of PA systems it is almost impossible to get efficiency AND
good LF performance.
A 30 foot concrete horn in a cinema type installation is good, and, if
organ music or a bowed bass is your listening pleasure, labyrinth type
will go down to around 80Hz.
But if its bass drums or a bass guitar, you need a lot of power and a
large surface area. And no reverse wave at all if possible. Enormous
impractical horn best, Infinite baffle second best, bass reflex third
best ...
Serried ranks of loudspeakers in a wall configuration works pretty well.
You always need the  most power for the bass loudspeakers for this very
reason. Its very hard to get the efficiency up.
>
Another thong mots people do NOT realise is how much louder a good
magnet  or horn design makes a loudspeaker, and how little louder
upping amplifier power makes it
>
10W=> 100W is just 10dB.  A loudspeaker going from 85dB/W to 105dB/W is
100 times more 'powerful'

The summer after high school, I built 3 (yes, an odd number)
cabinets of the Altec A-7 design from the drawings and measurements
photocopied from a library book.  While they weren't King Klipsch,
they did quite nicely on the title track of Chuck Mangione's
"Children of Sanchez" soundtrack, Pink Floyd's "Dark Side of the
Moon", Isao Tomita's "The Planets", and many others with 25-50W
per channel (home designed and built amp).  The drivers were rather
low quality relative to real Altec drivers, but they did okay.

Oh, the third speaker was center, L+R, and relative gain carefully
adjusted for optimum imaging.  The center speaker was the one I
used for the yearly candle-puffing ceremony.  The kick drum on
Chicago's "Saturday in the Park" would puff out a small candle
placed just in front of the woofer cone.

Sadly, had to sell two of the three to a movie theater a few
years later.

--
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)