It has been years since I have listened to A7 cabinets.
They are in no respect "flat", they have a HF rolloff, and a stepped LF response as the short mid horn transitions to bass reflex response.
The Fb is fairly high by today's standards, and the box is huge for it's limited LF.
The stepped LF response is useful for large rooms (theater size) but for most homes the extra 200-500 Hz (or 800 depending on crossover) horn bump is not desirable.
Other than nostalgia, there is no reason I would want to duplicate any of the attributes (other than high mid-band efficiency) of the A7 Voice of the Theater for home use.
Art
Unless you're me, and a number of people I know. 😉
I use the VOTT A5 (was A7) for home use and love it. Custom crossover. I've rarely heard better.
I use the VOTT A5 (was A7) for home use and love it. Custom crossover. I've rarely heard better.
Other than the HF horn dispersion and extension, transition between LF and HF, and the LF response, the A7/A5 are not bad.
Many, like you, find their sound quite euphonic.
Hi there: A pair of VOT's in a 3000 seat high school auditorium (pp807's mono amp) sounded fine in 1958, however my A7-800 drivers and HF horn have been boxed up since 73...bass response was not adequate for home hifi.
The VOTT speakers as I was once informed by a projectionist,were adjusted to suit what was known as the Academy Curve. The bass response was curtailed for various unconfirmed reasons one of which to prevent plaster mouldings in the ornate Art Deco theatres dislodging from the walls and ceilings.
Hi Pano, all
Ah the A7.
When I was a teen, I worked at a TV / hifi store after school and became sort of friends with a salesman that worked at a competitor’s real hifi store. One day he invited me to his tiny apartment in which he had a pair of A7’s. I recognized them as the company that did the sound at the Aragon Ballroom (in the late 60’s) used a large assortment of Altec theater cabinets.
I was stunned by the sound in the apartment and sitting about 8 feet away from a pair of such large cabinets seemed “right’.
Anyway some years back a friend had a stock A-7 that he wanted to make better sounding and louder if possible. I had never worked on one although I had used plenty of Altec horns in the past. I thought what would it be like to deal with one like a Synergy horn?
Here is the before and after curves. Note, the less flat curve is the stock one, the after curve has about an octave lower corner and a similar hf extension. Unfortunately, I took the “after curve” at 1V @ 2 meters while the stock one was at 1V@4 feet so the greater sensitivity of the modified one is not evident. It is a fire breathing monster comparatively due to greater sensitivity, much greater power handling as well as having an octave or more extension at each end..
Subjectively while I only listened to it for a few days but I was surprised that it struck me that it sounded much like one of our synergy horns, I suppose from the lack of crossover phase shift and hf driver.
It had been my intention to write an “upgrade” article back then; I took pictures and had made some notes on what I did. It involved several minor cabinet modifications (and moving the horn slightly, easy), new drivers (I used a 2226 and BMS4550) and a new crossover.
If there is interest in such a thing, I will find the old hard drive this stuff is on.
Best,
Tom Danley
Danley Sound Labs
Ah the A7.
When I was a teen, I worked at a TV / hifi store after school and became sort of friends with a salesman that worked at a competitor’s real hifi store. One day he invited me to his tiny apartment in which he had a pair of A7’s. I recognized them as the company that did the sound at the Aragon Ballroom (in the late 60’s) used a large assortment of Altec theater cabinets.
I was stunned by the sound in the apartment and sitting about 8 feet away from a pair of such large cabinets seemed “right’.
Anyway some years back a friend had a stock A-7 that he wanted to make better sounding and louder if possible. I had never worked on one although I had used plenty of Altec horns in the past. I thought what would it be like to deal with one like a Synergy horn?
Here is the before and after curves. Note, the less flat curve is the stock one, the after curve has about an octave lower corner and a similar hf extension. Unfortunately, I took the “after curve” at 1V @ 2 meters while the stock one was at 1V@4 feet so the greater sensitivity of the modified one is not evident. It is a fire breathing monster comparatively due to greater sensitivity, much greater power handling as well as having an octave or more extension at each end..
Subjectively while I only listened to it for a few days but I was surprised that it struck me that it sounded much like one of our synergy horns, I suppose from the lack of crossover phase shift and hf driver.
It had been my intention to write an “upgrade” article back then; I took pictures and had made some notes on what I did. It involved several minor cabinet modifications (and moving the horn slightly, easy), new drivers (I used a 2226 and BMS4550) and a new crossover.
If there is interest in such a thing, I will find the old hard drive this stuff is on.
Best,
Tom Danley
Danley Sound Labs
Attachments
They take much work to get around the original intent... which was superior speech in a 400 seat house, through a filmscreen. That said, once reworked they are much better than they have any right to be.
Once the cabinet is braced, horn damped and crossover upgraded / revoiced they sound like live instruments in real space. My wife had a pair in her office studio for a number of years... along with an assortment of violins and woodwinds.
Her comment, the A5 was a very good tool and the only speaker (and we've had some pretty well respected and expensive speakers in that room) that sounded like a violin when called to do so.
She gave them up for a very handsome Pass Labs speaker, that doesn't mean that they are not missed.... the A7 does some things like dynamic scale in a way that the average box speaker never gets quite right.
Cyclotronguy
Once the cabinet is braced, horn damped and crossover upgraded / revoiced they sound like live instruments in real space. My wife had a pair in her office studio for a number of years... along with an assortment of violins and woodwinds.
Her comment, the A5 was a very good tool and the only speaker (and we've had some pretty well respected and expensive speakers in that room) that sounded like a violin when called to do so.
She gave them up for a very handsome Pass Labs speaker, that doesn't mean that they are not missed.... the A7 does some things like dynamic scale in a way that the average box speaker never gets quite right.
Cyclotronguy
Last edited:
Ditto the above comments by Cyclo and Tom.
The stock A7 does not sound great as a home hi-fi speaker, in fact I think it sucks. No lows, aggressive, forward midrange, not great imaging, rattles and buzzes. No "euphonics" there. But with some work they can be transformed into world class.
As noted above, bracing and damping are essential. Not hard to, as there is plenty of room inside to work. 😉 Stiffening and damping the bass horn flares is also important as they are thin and were often not braced as they should have been. These are things you would do anyway if building from scratch.
Once that grunt work is done, the ports can be made smaller for extended bass and a new crossover will do wonders. I've documented most of these changes over on the Altec forum. I replaced the 511 horns and 1" drivers with the 1005 multi-cell and the 288 drivers. It's a whole other ball game now. They sound like real musicians playing real music on real instruments in a real space. And how that sounds changes greatly from one recording to the next, as it should.
The stock A7 does not sound great as a home hi-fi speaker, in fact I think it sucks. No lows, aggressive, forward midrange, not great imaging, rattles and buzzes. No "euphonics" there. But with some work they can be transformed into world class.
As noted above, bracing and damping are essential. Not hard to, as there is plenty of room inside to work. 😉 Stiffening and damping the bass horn flares is also important as they are thin and were often not braced as they should have been. These are things you would do anyway if building from scratch.
Once that grunt work is done, the ports can be made smaller for extended bass and a new crossover will do wonders. I've documented most of these changes over on the Altec forum. I replaced the 511 horns and 1" drivers with the 1005 multi-cell and the 288 drivers. It's a whole other ball game now. They sound like real musicians playing real music on real instruments in a real space. And how that sounds changes greatly from one recording to the next, as it should.
Can you recommend a good model to clone for home use? ,even if I had to scale them down a bit.
I'm liking the idea.
I'm liking the idea.
The Altec model 19 is well loved for home use. It's not small though. How big a box can you stand?
Bigger the better!
I like the "big voice of theater" models. (A7 type, but I see you guys don't recomend them for home use.)
I like the "big voice of theater" models. (A7 type, but I see you guys don't recomend them for home use.)
Last edited:
Altec 19
Hi there: Altec model 19 is 30"wide, 39"tall, 21"deep and weigh 143 pounds each. Google shows some for sale, one example was $1600 usd. ...regards, Michael
Hi there: Altec model 19 is 30"wide, 39"tall, 21"deep and weigh 143 pounds each. Google shows some for sale, one example was $1600 usd. ...regards, Michael
Not sure what you mean. Done right, they can sound great. I happen to love the multi-cell horns but a lot of folks are happy with the 511 or 811 horn. That would keep it as an A7-500 or A7-800. Sometimes there were turned upside down and the horn placed in the vent area to save space.
Still big fellows, tho.
Still big fellows, tho.
Hi there: Altec A-7 is 30" wide, 40.5" tall*, 24"deep and the height is increased by mounting the HF horn exposed above. *HF horns are of various sizes. ...regards, Michael
Thanks Michael and Pano.
I will build them, so the main obstacle will be getting some horns.
I figured I could play around with different drivers.
I liked the idea of these, rather then traditional "big" speakers.
I need some more bottom end without "EQ"ing on my PC - big volume is the way to go.
I have the option to bi-amp them as well.
I've got some reading to do. The A9 looks interesting too.
I will build them, so the main obstacle will be getting some horns.
I figured I could play around with different drivers.
I liked the idea of these, rather then traditional "big" speakers.
I need some more bottom end without "EQ"ing on my PC - big volume is the way to go.
I have the option to bi-amp them as well.
I've got some reading to do. The A9 looks interesting too.
- Status
- Not open for further replies.