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Movies Forum Index » Movie Technology Forum » Altec A8
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| Matthew |
 Posted: Sat Feb 16, 2008 9:17 am |
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I have three Altec A8 Voice of the Theatre speakers. Two of these
were used as surround speakers in a D-150 system here in Seattle, and
I removed them myself; the third came from a theatre in Michigan, but
I'm not sure in what capacity it was used.
I'm pretty familiar with the speakers from a technical standpoint. My
question is: Were many of these really sold, and for what purpose?
They were marketed toward theatres with little real estate behind the
screen (the speakers only need 12" depth), but did many theatres
really ever use them? I see the ubiquitous A7s mentioned all the
time, but I've only seen A8s on Ebay twice in 5 years, and I bought
one of them (the Grand Rapids speaker).
Insights appreciated.....
Matt Lutthans
Seattle
MLutthans@aol.com |
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| Peter |
| Posted: Sat Feb 16, 2008 4:40 pm |
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On 2008-02-16 11:17:57 -0800, Matthew <mlutthans@gmail.com> said:
Quote: I'm pretty familiar with the speakers from a technical standpoint. My
question is: Were many of these really sold, and for what purpose?
They were marketed toward theatres with little real estate behind the
screen (the speakers only need 12" depth), but did many theatres
really ever use them? I see the ubiquitous A7s mentioned all the
time, but I've only seen A8s on Ebay twice in 5 years, and I bought
one of them (the Grand Rapids speaker).
A7-500s were often found as screen channels in small theaters.
A5s and other As in larger theaters [ * ] .
The low and high frequency components, and the related crossover
networks, were selected from Altec's standard offerings, with the
larger As having more components, as needed.
A8s were small(ish) speakers intended for suround use. A8 is actually
the designation of the cabinet.
IIRC, the A8 cabinet could accommodate a 15" speaker, and Altec made several.
I doubt if the legendary 604 was intended to be installed in the A8
cabinet, although it might be possible.
A 604 ... a coaxial design which incorporates in one package the low
frequency cone of an A7 and the high frequency compression driver of an
A7 ... is a very expensive solution for a surround application.
Most probably one of the non-coaxial Altecs were used in the A8 cabinet.
Plans for the A8 cabinet exist, as do those for all the others.
I use a pair of A7-500s in my home theater now, and I have a pair of
Altec 604Cs in Altec utility cabinets for future surround use.
[ * ] Ampex Loudspeaker Corporation was founded to make speakers for
Ampex CinemaScope and Philips/Ampex Todd-AO installations. The cabinets
were derived from Altec designs, which, in turn, were derived from
Western Electric/Westrex designs, and these cabinets variously came
equipped with Ampex, Altec or Jim Lansing speakers, as Ampex
Loudspeaker Corp's production capacity could not meet its customer
demands. Ampex Loudspeaker Corporation was located down the street from
Jim Lansing.
--
CinemaScope®: The Modern Miracle You See without Special Glasses!
--
Peter |
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| Bill Vermillion |
| Posted: Sat Feb 16, 2008 8:26 pm |
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In article <2008021612405416807-peterh5322@rattlebraincomminch>,
Peter <peterh5322@rattlebrain.comminch> wrote:
Quote: On 2008-02-16 11:17:57 -0800, Matthew <mlutthans@gmail.com> said:
I'm pretty familiar with the speakers from a technical standpoint. My
question is: Were many of these really sold, and for what purpose?
They were marketed toward theatres with little real estate behind the
screen (the speakers only need 12" depth), but did many theatres
really ever use them? I see the ubiquitous A7s mentioned all the
time, but I've only seen A8s on Ebay twice in 5 years, and I bought
one of them (the Grand Rapids speaker).
A7-500s were often found as screen channels in small theaters.
And they were also in use in many recording studios.
There were 4 of them hung from chains in the Columbia
studios in Nashville [the old Bradley's barn] and I still have fond
memories of Bob Johnson playing the first three tracks that Bob
Dylan had cut in about 3 or 4 years.
We had a pair in our warehouse studio before we built a world-class
facility. Damned efficient. As I recall they would output
103db at 1 meter with 1 watt.
Bill
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Bill Vermillion - bv @ wjv . com |
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| Guest |
| Posted: Sat Feb 16, 2008 8:42 pm |
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On Feb 16, 2:17 pm, Matthew <mlutth...@gmail.com> wrote:
Quote: I have three Altec A8 Voice of the Theatre speakers. Two of these
were used as surround speakers in a D-150 system here in Seattle, and
I removed them myself; the third came from a theatre in Michigan, but
I'm not sure in what capacity it was used.
I'm pretty familiar with the speakers from a technical standpoint. My
question is: Were many of these really sold, and for what purpose?
They were marketed toward theatres with little real estate behind the
screen (the speakers only need 12" depth), but did many theatres
really ever use them? I see the ubiquitous A7s mentioned all the
time, but I've only seen A8s on Ebay twice in 5 years, and I bought
one of them (the Grand Rapids speaker).
Insights appreciated.....
Matt Lutthans
Seattle
MLutth...@aol.com
Matt,
The A8 was indeed sold and used in many a theatre, unfortunately. Its
main, if not only claim to fame is its depth, or lack there of. Its
response is definately wanting. By the end of the production (I think
it was called A8C), they had an access plate on the top to change the
diaphragm (the horn had a 90-degree bend in it to have the back of the
driver pointing ot the top) and the crossover/speaker input was on the
side...in short, you didn't need to get to the rear of the cabinet.
The last theatre I personally installed new ones in was the Dupont
Circle 5 in Washington, DC. Those were tiny theatres and the speaker,
as shallow as they were, just barely fit! I still see them in use
today as stage speakers but thankfully not too often. Their response
really isn't all that great. I have no problems with A5s and A4s but
the A8s were for just one thing...to fit. In fact, I still use A5s to
this day. The Ambler theatre Ambler, PA just received a set,
refirbished with new LF drivers (515-8GHP), diaphragms and Mantary
horns. The Altec Mantary remains my favorite CD type horn. Given the
right auditorium, I would still use an A4 to this day but it better be
a big auditorium.
SG |
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| Peter |
| Posted: Sat Feb 16, 2008 8:43 pm |
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On 2008-02-16 16:26:20 -0800, bv@wjv.com (Bill Vermillion) said:
Quote: We had a pair in our warehouse studio before we built a world-class
facility. Damned efficient. As I recall they would output
103db at 1 meter with 1 watt.
I drive my pair with 5 watts from the "Class H" ouput section of a
name-brand stereo TV.
The Class H probably expects 4 ohms, but it doesn't seem to have any
problem at all with the 16 ohms of the A7-500s.
32 ohm Altecs are known, too.
--
CinemaScope®: The Modern Miracle You See without Special Glasses!
--
Peter |
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| Scott Dorsey |
| Posted: Sun Feb 17, 2008 12:48 pm |
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Peter <peterh5322@rattlebrain.comminch> wrote:
Quote: On 2008-02-16 16:26:20 -0800, bv@wjv.com (Bill Vermillion) said:
We had a pair in our warehouse studio before we built a world-class
facility. Damned efficient. As I recall they would output
103db at 1 meter with 1 watt.
I drive my pair with 5 watts from the "Class H" ouput section of a
name-brand stereo TV.
The Class H probably expects 4 ohms, but it doesn't seem to have any
problem at all with the 16 ohms of the A7-500s.
32 ohm Altecs are known, too.
Also 24. Note that as the impedance goes up, the voice coil mass goes
up too, and the top end response gets worse. Those 800-series compression
drivers sound a LOT better with an 8-ohm diaphragm than a 24-ohm one.
--scott
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"C'est un Nagra. C'est suisse, et tres, tres precis." |
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| Peter |
| Posted: Sun Feb 17, 2008 2:55 pm |
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On 2008-02-17 08:48:55 -0800, kludge@panix.com (Scott Dorsey) said:
Quote: Also 24. Note that as the impedance goes up, the voice coil mass goes
up too, and the top end response gets worse. Those 800-series compression
drivers sound a LOT better with an 8-ohm diaphragm than a 24-ohm one.
Altecs were intended to be driven from a 70.7 volt system, and a
driving amp with a low source impedance and a huge damping factor is
not a good source, unless a build-out resistor is added.
--
CinemaScope®: The Modern Miracle You See without Special Glasses!
--
Peter |
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| Scott Dorsey |
| Posted: Sun Feb 17, 2008 3:12 pm |
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Peter <peterh5322@rattlebrain.comminch> wrote:
Quote: On 2008-02-17 08:48:55 -0800, kludge@panix.com (Scott Dorsey) said:
Also 24. Note that as the impedance goes up, the voice coil mass goes
up too, and the top end response gets worse. Those 800-series compression
drivers sound a LOT better with an 8-ohm diaphragm than a 24-ohm one.
Altecs were intended to be driven from a 70.7 volt system, and a
driving amp with a low source impedance and a huge damping factor is
not a good source, unless a build-out resistor is added.
That's a different issue. That's the issue of the damping on the bass
cabinet being designed for a tube-type power amplifier with an output
transformer and comparatively high output Z.
In fact, if you are driving off a modern low-Z power amplifier, a series power
resistor can help reduce the low end damping a bit.
--scott
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"C'est un Nagra. C'est suisse, et tres, tres precis." |
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| Peter |
| Posted: Sun Feb 17, 2008 3:43 pm |
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On 2008-02-17 11:12:48 -0800, kludge@panix.com (Scott Dorsey) said:
Quote: Altecs were intended to be driven from a 70.7 volt system, and a
driving amp with a low source impedance and a huge damping factor is
not a good source, unless a build-out resistor is added.
That's a different issue. That's the issue of the damping on the bass
cabinet being designed for a tube-type power amplifier with an output
transformer and comparatively high output Z.
Yup.
Quote:
In fact, if you are driving off a modern low-Z power amplifier, a series power
resistor can help reduce the low end damping a bit.
-
Yup, squared.
The Ampex CinemaScope power amps (the same were used in the
Philips/Ampex Todd-AO system) didn't have a lot of negative feedback,
so the source impedance was reasonably high for the intended
application.
--
CinemaScope®: The Modern Miracle You See without Special Glasses!
--
Peter |
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