"DoN. Nichols" wrote in message
...
In article ,
Harold and Susan Vordos wrote:

"DoN. Nichols" wrote in message
...
In article ,
Harold and Susan Vordos wrote:
snip-

What I would be more concerned about with that length is
possible loss of control of speaker overtravel, thanks to the added
resistance.

That's something I didn't understand. I guess that relates to a systems
ability to dampen. Feel free to correct me if I'm wrong.

You are correct. Perhaps a short explanation will help you to
understand. First off -- you want the minimum output impedance from
your amplifier, so when it wants to put out precisely 2.37 volts, it
*really* produces 2.37 volts, regardless of load (within reason -- a
short circuit can't be driven by the amp.

Now -- when you start to move the speaker cone, you do so by
applying a voltage to the voice coil. But when that coil moves in the
magnetic field, it generates a voltage of its own. If you draw current
from that, it loads down the motion of the cone, drawing energy from it.
(Like a motor overspeed will act as a generator.) The lower the
impedance of the amplifier -- and *everything* between the amplifier and
the speaker coil -- the more this motion-generated voltage will produce
a current in the opposite direction to slow down or stop the speaker.
If it is allowed to overshoot, it will introduce motion into the air
(sound) which does *not* correspond to the original recorded sound --
which we call distortion (one of many forms).

Speakers, BTW, should not be considered separate from their
enclosures. If you get a good quality speaker, and just put it cone up
on a table, and connect a 1.5V flashlight battery to it, you will hear a
"thump" sound. That means that there is a lot of low frequency
involved.

Now -- in an enclosure, the sound will be closer to a "click",
which is the true representation of the voltage step produced by the
battery. The better the speaker enclosure, and its match to the
speaker, the cleaner the "click" sound will be, and the less "thump".
(That "thump" translates into a boost in the bass curve compared to the
higher frequencies -- a "boomy" sound.)

The perfect match will produce a very clean and clear "click".
However -- if you add a resistor in series with the battery and speaker
voice coil, you will lose some of that clean click as the speaker
overshoots, comes back, undershoots, and so on until it finally stops
moving -- until you disconnect the battery.


Thanks for taking the time to discuss it. I was aware of the importance
of the enclosure as it relates to the speakers---and in the case of the S8R
system, JBL did something to overcome the relatively small enclosures (as
compared to the woofer, which is 15") by adding what they call a passive
radiator. A speaker without a voice coil and magnet, which, obviously,
works directly out of phase with the woofer, allowing it to have a somewhat
greater throw, therefore a slightly improved low end, at least from the
standpoint of the listener. I have no clue how it works out when subjected
to the scrutiny of instruments.

Considering we also own a Paragon, which is, for the most part, almost
identical as far as speakers go, the difference between the two is
noticeable. The Paragon doesn't have the passive radiator, but has an
exponential horn type construction, reflecting the low end off a baffle that
mounts as the base of the horn. It's clearly a better sound. I've never
been a fan of a booming low end, although I certainly do enjoy hearing a
system that has a good one. By running the Paragon and the Olympus
speakers in parallel, I get what is, to me, a very nice sound. A bit shrill
on occasion, due in part to the tweeters and mid range being horns. Of
all the speakers I listened to when I made my purchase, the only other sound
I much cared for was the wonderful, rich full sound that came from Bozak
Concert Grands, but they weren't nearly as attractive to me, and were, I
would assume, power hogs.

That helps. My wife won't listen to classical, though I used
to. But we are pretty much in agreement for the rest. (And we met
through the local Folklore Society. :-)

Too bad she hasn't warmed up to the classics. That kind of listening
really
has a place, at least in our lives.

Yep -- but with all else considered, I have no real complaints.
She even puts up with my shop. :-)

Having been through one divorce, I feel I can safely say that the value of a
good woman is difficult to determine. If your wife is anything like mine,
she just very well may be the most valuable asset you have. I have
received nothing but total cooperation from Susan in all our married life.
Right down to encouraging me to buy machines, which I rarely do.

You know -- you can get small CD recorders so you can play the
record *once* more into the recorder, and burn a CD from that, which you
can then use for many years without subjecting either the vinyl record
or the stylus (which will probably also become difficult to replace) to
more wear.


Yeah, I've given that idea considerable thought. The only thing that's
troubling is the size of the collection. With over 1,000 records, I can't
imagine ever getting them all done, but I fully intend to record at least
those that I consider my favorites. I'm sure you have certain recordings
that hold a special place in your heart. I know I do.

One of the problems with jazz is that for the most part, the grand masters
that went before us are almost all gone. While I respect the attempts of
those behind them, it's not the same. Just as in your folk music, the end
result is influenced heavily by what's happening at the moment. As
wonderful as Brubeck is today, the music he created when he was in his
younger years, performing with Desmond, will never be again. Therefore,
it's important that I retain what, to me, is what the music represents.


It was not until I was working at an
Army R&D lab that I got a chance to learn machining from a couple of
resident machinists -- and I have been glad that I did. (Of course,
before that, I was trying to do things like building a tape deck for
10-1/2" reels from scratch -- mostly with hand tools and an electric
drill motor -- and files and coping saws. :-)

After looking at the high level of precision used in building the Crown
we
own, and the sophisticated controls it has, I can't even begin to
understand
how a novice would go about building such a device. I really admire
your
courage! I trust you were not successful, not with hand tools. g

Well ... I was successful enough so I could play tapes on it.
The motors which I used for spindle motors did not allow really good
control of fast tape motion, so I had to wait for it to run off the
supply reel. And in particular, I did not have the tools to make proper
brakes.

That's certainly more success than I had imagined.


But -- I then picked up an Ampex 440B recorder at a surplus
sale, and later a Revox A700, so I was all set from then until I moved
to DATs for recording. *Those* I bought new. :-)

I bought a Teac (I think it was an A 7010) new----which was enough to
convince me that if I ever bought another deck, and I sure as hell would, it
would be a Crown. It was lacking in the quality I had hoped for.

They're (tape decks in general) really outmoded today, but I still enjoy
playing with it. I'm not in this to keep up with the Jones's, only to make
myself happy. I am.

Harold