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| Author |
Message |
keesan
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Equipment for playing music
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Mar 17 00:26 UTC 2002 |
Discuss the hardware aspects of playing music - tape decks, receivers,
CD-players, boomboxes, etc.
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| 65 responses total. |
keesan
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response 1 of 65:
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Mar 17 00:30 UTC 2002 |
We have seen numerous boomboxes with a switch on the back labelled OSC on/off
or beat cut A B or even A B C. Does this apply to the tape or radio, and what
exactly does it do?
On some tape decks there is a button or level labelled Memory (on/off). How
does this work? And how do you use MPX filter on a tape deck - it is
sometimes associated with Dolby? Does a Limiter switch limit the peak volume?
What is auto repeat used for? Some decks have a timer feature - where do you
get a timer to go with it and what would they cost, or can you make one?
On a CD player, what do auto cue and time mode do? I discovred what hitting
repeat does - it plays the same track over and over and over and over....
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keesan
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response 2 of 65:
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Mar 17 00:39 UTC 2002 |
Jim asks what happens if you put 3 ohm speakers on a boombox that calls for
4 ohm speakers, will it damage either the speakers or the boombox if you don't
play music loudly? He is proud to report that he is halfway through replacing
the foam surrounds of a couple of AR woofers with foam surrounds that he
carefully removed from some passive radiators (they look like speakers but
have no magnet or coil). Today he glued (with carpenter's glue) the foam to
the cones, and tomorrow when it is dry he will glue foam to metal frame.
www.simplyspeakers.com sells new foam surrounds for $27/pair and was kind
enough to tell him old ones could be reused, and emailed instructions. Remove
the old foam with sharp knife and alcohol. He also glued the loose copper
coil of another speaker back into its cardboard tube, with superglue, after
carefully slicing off the dust cap (which he will glue back on tomorrow).
It probably came loose when someone played very loud music. THe matching
speaker to the pair had a broken wire which probably happened after the coil
came unglued. Perhaps the glue just dried out first.
The neighbor gave him the superglue, along with a 10" woofer that has a
disintegrating cone. Anyone have any dead 10" speakers to give away?
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krj
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response 3 of 65:
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Mar 18 21:04 UTC 2002 |
((( Classical 65 <---> Music 82 )))
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krj
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response 4 of 65:
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Mar 18 21:12 UTC 2002 |
The MPX filter on tape decks is designed to get
rid of the 19kHz pilot signal ("multiplex carrier"?)
which is part of the FM radio signal. That signal can trick the
Dolby noise-reduction circuitry into misbehaving, and it may cause some
other effects; I've just noticed that in my recent taping of FM radio,
I get a lot of funny effects unless the MPX filter is on.
Someone else needs to explain the theory of how FM Stereo works,
and how it was desgined to be compatible with monaural FM.
MPX filter should theoretically be left off for tapes from other sources
such as records and CDs, though at our age, and with the presumed quality
of tape decks you are using, it probably wouldn't be a problem to
leave the 19kHz filter on all the time. Experiment!
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krj
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response 5 of 65:
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Mar 18 21:18 UTC 2002 |
For a tape deck designed to work with a timer, any external timer which
would control an AC power outlet would do. The "timer" switch
generally has two choices: one to start tape playing when the power
comes on, and one to start tape recording when the power comes on.
If you want to use your equipment to record on power-on,
you have to be VERY, VERY CAREFUL about tape management,
otherwise eventually you will make the mistake of turning the
machine on while a valued cassette is in the machine,
and the machine will merrily erase the recording.
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keesan
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response 6 of 65:
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Mar 18 21:58 UTC 2002 |
Thanks Ken. We only listen to FM radio in mono because of the hiss in stereo
when listening to any but strong local stations (none of which we listen to)
so should be safe recording without the MPX filter.
The Beat Cut A B C is for recording from AM if there is a whistle - try out
all three until one works.
We have several timers of the sort where you push little square pins/knobs
to the inside or outside of the timer to set it to go on or off every half
hour which we may experiment with. Our friend likes to record a particular
radio show and keeps buying VCRs to do it with because they are timed.
These are sold for lamp timers but they are also nice for turning an electric
mattress pad on or off.
The foam surround project and the glue the coil in the tube project were both
complete successes and we are now trying to determine which two of four
woofers sound better together.
The instructions that came with one tape deck had a picture of what looked
like a stereo component, labelled timer, which looked expensive. I suppose
if we don't mind being within 10 minutes the cheap sort will also work.
There is a little picture of a clock or timer next to the play and record
switches on one tape deck. I guess you can also set it to work as an alarm
clock but there seems to be no sleep or snooze switch.
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jaklumen
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response 7 of 65:
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Mar 19 02:44 UTC 2002 |
Sindi, Jim should have little problem using 3 ohm speakers where 4 ohm
ones are required. I don't think you'll blow them out, since I
*highly* doubt you play music at maximum levels and music which
strains the whole frequency of the speaker. Classical music isn't
known for that. Modern music recorded in the studio-- say, techno,
dance, etc., will be harder on them.
My system calls for 8 ohm- 16 ohm speakers, I believe. I use an
Optimus dual-coil subwoofer rated at 8 ohms, and two KLH 3-way
satellites rated at 6 ohms each. I'm only using the A set of drivers
(it's a 140W stereo receiver).
The ohm ratings are only one part of the deal with speakers.
Generally-- you want most of your resistance in the midrange speakers,
with fairly little in the others, especially subwoofers. Are we
talking one-way speakers? The ohm rating can dip really low for the
others (you can get 1/2 ohm resistors for subs), so as long as you've
got your midrange area decently covered, and in this case, it sounds
like about 4 ohms, you should be perfectly safe.
(hehe, I told you this was a hobby of mine.)
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rcurl
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response 8 of 65:
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Mar 19 06:47 UTC 2002 |
Those "ohms" are not resistance - they are impedances, and represent
the impedance matching between the source (amplifier) and the
atmosphere (the sound production). A mismatch primarily reduces
the efficiency of power transfer. However, because of other factors
in the component behaviors, a mismatch can also affect frequency
response and distortion.
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