I'd like some feedback regarding specifications for some speakers &
crossovers I have.

A few years back, my parents gave me their old '60s Magnavox console stereo
after it "died" because I'd mentioned interest in those HUGE woofers and
horns.

I had no interest in the dead control/amplifier units so I merely scavenged
the speakers and crossovers, chunked the dead hardware and used the cabinet
for fireplace kindling.

I never thought to notice this unit's model number. But now that I am
wanting to put these thing to use, I cannot determine what the speaker/horn
specs are nor the values of the unmarked crossover components.

I'd like to know what these speakers are rated at & whether they are 4, 8 or
ohm. I'd like to recreate the original x-overs. I've tested a couple of
different sets of commercially produced x-overs (connected to 4, 8 & 16 ohm
outputs) but like the sound better through the originals.

Here is what I do know:
This unit was one of Magnavox's first solid-state versions ca. 1965.
It was about 6 feet long with removable sliding wooden panels on the top.
The control unit and record-changer were in the right-hand side.
An album storage bin and speaker selector switch were located in the
left-had side
The amp was 50 watts and was remotely located in the bottom of the cabinet.
The woofers are 15" in diameter and say, "Magnavox 581515-1 719"
The horns are 11.5"x5" aluminum and about 12" long (no markings).
The tuner was AM/FM/Multiplex.
It sported a Gerrard record-changer.
The x-overs were actually combined on one cardboard circuit board.
There was no baffling for the speakers... the cabinet acted as one giant
plenum.

Testing will be required, obviously. I'll refer you to the library for
the correct procedure. You will need only that test equipment without
which you don't belong fooling with this stuff. (Nothing terribly
expensive.)

- - : R A T B o y : - - wrote:


I'd like to know what these speakers are rated at & whether they are 4, 8 or
ohm.

An ohmmeter will get you a close (20%) read on the impedance of
a speaker. Other than comparing the physical size of the
voice coil and magnet to known speakers, not sure how to
identify power rating.

Thanks, Bob.

The system was advertised at 50 watts. Possibly it was 25 wpc. So, I
expect at least 25w. This is the least of my worries.

A set of frequency curves would help me build substitute x-overs. I figure
Magnavox used a variety of speaker suppliers and models so I am hoping the
previously described markings will mean something to someone.

Also, I measured the individual speaker resistances:
The horns show 11ohms resistance and the woofers 7.6 ohms. According to
your suggestion 20% variances approximate the following:
4 ohms +/- 20% = between 3.2 & 4.8 ohms
8 ohms +/- 20% = between 6.4 & 9.6 ohms
16 ohms +/- 20% = between 12.8 & 19.2 ohms
This suggests that they could possibly be 16 and 8 ohms... would the old
crossovers have compensated for this? They were very simple (a big cap, a
ferrite coil and a wound resistor (big rectangular clay thingy).

Obviously, an audio frequency generator and a o-scope would allow me to plot
my own curves... fat chance I'd pop for these. I do, however, have a stereo
FM signal generator... but I do not know if this could be used for audio.


"robert casey" wrote in message
link.net...
- - : R A T B o y : - - wrote:


I'd like to know what these speakers are rated at & whether they are 4, 8
or ohm.

An ohmmeter will get you a close (20%) read on the impedance of
a speaker. Other than comparing the physical size of the
voice coil and magnet to known speakers, not sure how to
identify power rating.

- - : R A T B o y : - - wrote:

snip

Obviously, an audio frequency generator and a o-scope would allow me
to plot
my own curves... fat chance I'd pop for these. I do, however, have a
stereo
FM signal generator... but I do not know if this could be used for
audio.


If a good look at the front panel does not sufficiently answer this
question you are too _stupid_ for this hobby. But seeing as this is
also true of many, many regular posters to this NG it would at least
put you in good company.

THese were 8 ohm speakers, if this is the SS update of the original tube
based unit that was made into the mid 60's. From your description it sounds
like the identical console unit I picked up at a garage sale for $1. Did
you save the magic eye tube?

Woofer frequency only goes down to about 45 hertz, then they start
frequency doubling.

Original tube unit was biamped--no xover. Used a P-P for woofers, and SET
6V6 in triode mode for horn tweeter. Xover was at about 1100Hz accomplished
with a tunable hound wound inductor circuit feeding the driver tube for the
SET 6V6. I suspect they just used an external xover to try to duplicate
tube bi-amp response. Probably sounded like crap. Good choice to junk the
SS hardware/

Original was quite a marvel in design. I've got the scematic for it
somewhere.

Now if it had been the tube version--you'd have something. I rebuilt one
and ran it for awhile--really an amazingly good sounding unit for it's time.

Also, the cabinet is valuable these days. I sold mine to a vintage shop who
converted it to a mini-bar and sold for good $$.






"- - : R A T B o y : - -" - - : R A T B o y : - wrote in
message ...
I'd like some feedback regarding specifications for some speakers &
crossovers I have.

A few years back, my parents gave me their old '60s Magnavox console
stereo after it "died" because I'd mentioned interest in those HUGE
woofers and horns.

I had no interest in the dead control/amplifier units so I merely
scavenged the speakers and crossovers, chunked the dead hardware and used
the cabinet for fireplace kindling.

I never thought to notice this unit's model number. But now that I am
wanting to put these thing to use, I cannot determine what the
speaker/horn specs are nor the values of the unmarked crossover
components.

I'd like to know what these speakers are rated at & whether they are 4, 8
or ohm. I'd like to recreate the original x-overs. I've tested a couple
of different sets of commercially produced x-overs (connected to 4, 8 & 16
ohm outputs) but like the sound better through the originals.

Here is what I do know:
This unit was one of Magnavox's first solid-state versions ca. 1965.
It was about 6 feet long with removable sliding wooden panels on the top.
The control unit and record-changer were in the right-hand side.
An album storage bin and speaker selector switch were located in the
left-had side
The amp was 50 watts and was remotely located in the bottom of the
cabinet.
The woofers are 15" in diameter and say, "Magnavox 581515-1 719"
The horns are 11.5"x5" aluminum and about 12" long (no markings).
The tuner was AM/FM/Multiplex.
It sported a Gerrard record-changer.
The x-overs were actually combined on one cardboard circuit board.
There was no baffling for the speakers... the cabinet acted as one giant
plenum.

Yep sounds like the one I scraped some time back.The 15 inchwoofers are
CTS,the horns are Magnavox/Jensen.The xovers are nothing special.The horns
are sold on line often.The woofers would make alot of sound of so so
quality.I was thinking of a guitar cab for them.
WesJ........

FM signal generator... but I do not know if this could be used for

audio.


If a good look at the front panel does not sufficiently answer this
question you are too _stupid_ for this hobby. But seeing as this is
also true of many, many regular posters to this NG it would at least
put you in good company.


You'd make an excellent candidate for ambassador at the UN;
hurry and submit an application as I hear there's an opening
there now......

If the FM stereo sig generator doesn't have an audio output jack,
use a receiver to get the audio.

Calcerise,

If you'd actually READ the original posting you could have saved yourself
the effort of trying to put me in my place.

You are a sophomoric ****head! Talk to the TWIT filter because the
newsreader 'aint listening.



wrote in message
oups.com...

...

If a good look at the front panel does not sufficiently answer this
question you are too _stupid_ for this hobby. But seeing as this is
also true of many, many regular posters to this NG it would at least
put you in good company.

Or buy a audio generator like a non-idiot.

RB,
Madisound might be able to help you with the old crossovers. They had once
offered to measure and redesign a crossover I was having a similar problem
with. www.madisound.com might be worth an email.
Mark
"- - : R A T B o y : - -" - - : R A T B o y : - wrote in
message ...
Thanks, Bob.

The system was advertised at 50 watts. Possibly it was 25 wpc. So, I
expect at least 25w. This is the least of my worries.

A set of frequency curves would help me build substitute x-overs. I
figure Magnavox used a variety of speaker suppliers and models so I am
hoping the previously described markings will mean something to someone.

Also, I measured the individual speaker resistances:
The horns show 11ohms resistance and the woofers 7.6 ohms. According to
your suggestion 20% variances approximate the following:
4 ohms +/- 20% = between 3.2 & 4.8 ohms
8 ohms +/- 20% = between 6.4 & 9.6 ohms
16 ohms +/- 20% = between 12.8 & 19.2 ohms
This suggests that they could possibly be 16 and 8 ohms... would the old
crossovers have compensated for this? They were very simple (a big cap, a
ferrite coil and a wound resistor (big rectangular clay thingy).

Obviously, an audio frequency generator and a o-scope would allow me to
plot my own curves... fat chance I'd pop for these. I do, however, have a
stereo FM signal generator... but I do not know if this could be used for
audio.


"robert casey" wrote in message
link.net...
- - : R A T B o y : - - wrote:


I'd like to know what these speakers are rated at & whether they are 4,
8 or ohm.

An ohmmeter will get you a close (20%) read on the impedance of
a speaker. Other than comparing the physical size of the
voice coil and magnet to known speakers, not sure how to
identify power rating.