Thought I might share my ongoing nightmare with you all.
Save any who might fall into this black pit of endless bottomless dispair from my fate!!
The short version: Altec A-7 cabinets are built so badly by modern standards that they are almost worthless, imho! Bringing them up to a reasonable level of solidity of construction is as much or more work than building from scratch! True.
It is amazing that they were able to be thrown about on the road as much as these "venerable old warhorses" are/were, without just shattering and falling apart.
Well, actually they did - based on the angle bracket repairs to one of the two cabinets that fell into my unlucky lap!
Cheesy plywood, low grade, nails, insufficient glue and tiny almost worthless glue blocks between cabinet walls. That's an A-7 stock.
The walls are too thin and unstiff - they have to be stiffened.
The cabinet leaks.
The speaker mounting throat does not fit flush to the "horn".
The horn is made of thin, kerf'd plywood, and is unstiff and undamped.
Everything rings, and is undamped.
The corners of "roaded" boxes are shot and beaten.
The bottoms are so bad they need to be replaced.
The outside is beaten into submission, no repairs to the finish is possible.
The strips that hold the back cover are riddled with holes and since they are nailed and lightly glued to second rated, now delaminating plywood, are almost not connected to the box.
The quality of the wood used where wood was used is laughable - one box even had wood stips with bark still on it!
And on and on and on...
More to come...
_-_-bear
Save any who might fall into this black pit of endless bottomless dispair from my fate!!
The short version: Altec A-7 cabinets are built so badly by modern standards that they are almost worthless, imho! Bringing them up to a reasonable level of solidity of construction is as much or more work than building from scratch! True.
It is amazing that they were able to be thrown about on the road as much as these "venerable old warhorses" are/were, without just shattering and falling apart.
Well, actually they did - based on the angle bracket repairs to one of the two cabinets that fell into my unlucky lap!
Cheesy plywood, low grade, nails, insufficient glue and tiny almost worthless glue blocks between cabinet walls. That's an A-7 stock.
The walls are too thin and unstiff - they have to be stiffened.
The cabinet leaks.
The speaker mounting throat does not fit flush to the "horn".
The horn is made of thin, kerf'd plywood, and is unstiff and undamped.
Everything rings, and is undamped.
The corners of "roaded" boxes are shot and beaten.
The bottoms are so bad they need to be replaced.
The outside is beaten into submission, no repairs to the finish is possible.
The strips that hold the back cover are riddled with holes and since they are nailed and lightly glued to second rated, now delaminating plywood, are almost not connected to the box.
The quality of the wood used where wood was used is laughable - one box even had wood stips with bark still on it!
And on and on and on...
More to come...
_-_-bear
Howdy Bear, Did you ever consider that the whole A-7 sound people go nuts for is a direct result of there shoddy construction? Thin panels resonate adding acoustic energy to the room. It's not accurate but it may be part and parcel to that " dynamic vintage sound" people love so much. If you like that sound(not my cup of tea by the way) you might want to reproduce the cabinet using better quality construction yet keep the thin panels of the original. It's a dirty little secret that many of the classic speakers from the "golden age of audio" were slaped together like tree forts!
Bear,
Is this the first pair you have become intimate with? Between the cabinets humming and the horns ringing you'd think they wouldn't sell at all, let alone for thousands of dollars.
They remind me of the old E series Jags. Some people love them. I'm happen to one of them. The day the empty cabinets arrived from Seattle I just about peed myself because as a lad I had grown up idolizing them. Just goes to show you the effect something "so bad" can have on you.
After all is said and done, there's just something magical about that box.
Is this the first pair you have become intimate with? Between the cabinets humming and the horns ringing you'd think they wouldn't sell at all, let alone for thousands of dollars.
They remind me of the old E series Jags. Some people love them. I'm happen to one of them. The day the empty cabinets arrived from Seattle I just about peed myself because as a lad I had grown up idolizing them. Just goes to show you the effect something "so bad" can have on you.
After all is said and done, there's just something magical about that box.
Could have been worse. They could have used hot glue to put them together. The hot glue applications on most consumer speakers of that era would have had more secure bonds if the assemblers had used genuine authentic, hand picked snot. 
Uhhh, that IS hot glue in these old speakers yes?
I have four authentic original Altec A-7 cabinets and they are under built for sure. At least mine came from theater installs and were not beaten up. Because these throw a good ways and sound best 25-30+ feet out front where the phase clearly comes into alignment one does not hear the cabinet issues. I never found them to be listenable in the near field, as in a average living room.
Uhhh, that IS hot glue in these old speakers yes?
I have four authentic original Altec A-7 cabinets and they are under built for sure. At least mine came from theater installs and were not beaten up. Because these throw a good ways and sound best 25-30+ feet out front where the phase clearly comes into alignment one does not hear the cabinet issues. I never found them to be listenable in the near field, as in a average living room.
rcavictim said:Could have been worse. They could have used hot glue to put them together. The hot glue applications on most consumer speakers of that era would have had more secure bonds if the assemblers had used genuine authentic, hand picked snot.
Uhhh, that IS hot glue in these old speakers yes?
By "hot glue"', do you mean hot melt glue, or hide glue, which is melted in a heated pot for application?
Top notch musical instruments are still built with hide glue, and some believe that you can't get good tone from anything else. Maybe that was Altecs secret?
Hey Bear - I know what you mean!
Here is a pair I rebuilt about 20 years ago on Paris.
These are still the reference system at the Magazine "Revue du Son."
This pair was in pretty good shape, I think they had come out of a cinema. The work consisted of:
Results? Pure magic. Still my favorite speakers.
The bass is big, but has NO box sound. The only cabinets I've ever heard that don't. This goes a loooong way to making them sound like real music. And they do, they nail it. Plus they do all that 3D imaging stuff amazingly well - but that's the horns, I suppose.
The box design is a good one, a great one. But they were poorly made. As I understand it, many were built locally in the country they were sold in. Maybe some Altec guys can confirm that.
Older sound guys would look at me and chuckle when I told them my favorite speaker is an A7. But they never got to hear one like this.
Here is a pair I rebuilt about 20 years ago on Paris.
These are still the reference system at the Magazine "Revue du Son."
This pair was in pretty good shape, I think they had come out of a cinema. The work consisted of:
- Doubling up most of the walls. Done with 18 or 20mm Nantex marine plywood. The heaviest, densest, hardest wood I've ever seen! Extremely difficult to cut and drill. More like working with iron than wood. IIRC, the new panels were added on the inside, but I could be wrong.
- Cross bracing added inside, of course. Same wood.
- Tar added to the back of the kerfed horn. Some non-drying stuff that came in a can.
- Corners reinforced inside.
- Port size reduced.
- Wool felt used for damping
Results? Pure magic. Still my favorite speakers.
The bass is big, but has NO box sound. The only cabinets I've ever heard that don't. This goes a loooong way to making them sound like real music. And they do, they nail it. Plus they do all that 3D imaging stuff amazingly well - but that's the horns, I suppose.
The box design is a good one, a great one. But they were poorly made. As I understand it, many were built locally in the country they were sold in. Maybe some Altec guys can confirm that.
Older sound guys would look at me and chuckle when I told them my favorite speaker is an A7. But they never got to hear one like this.
Lousy,
Yes. I was referring to hot melt LDPE that is dispensed from an electrically heated gun, usually onto stone cold surfaces which cool it solid before the surfaces can wet. The pieces are pressed together making a poorly bonded joint which has a lump of frozen LDPE in it preventing the pieces to be tightly fitted together.
Yes. I was referring to hot melt LDPE that is dispensed from an electrically heated gun, usually onto stone cold surfaces which cool it solid before the surfaces can wet. The pieces are pressed together making a poorly bonded joint which has a lump of frozen LDPE in it preventing the pieces to be tightly fitted together.
Panomaniac,
Yeah, nice. I think I've seen pix of these before, and others like that in France... I have a few copies of Revue De Son here...
What did you put on the rear of the curved horn sections to stiffen them up? I haven't committed to anything yet, but by next weekend it will be done!
Cal and rcavictim, etc...
No this is not the first pair I have dealt with.
It is the first pair that I have been asked to rebuild and include in a system for the home! :_)
Used many and put drivers into many for PA use... imho they always sounded like ca-ca, but back in the day there were few if any other choices around! And it is amazing the abuse they put up with...
The cast aluminum horns are awful, imho.
The folks who persist in using them, I dunno about.
Around here we use <300Hz. horns for home application.
As I mentioned before, nothing you can do with a stock Altec driver will get you below 50Hz - and the stock "port" is "untuned" and lets so very much midbass through it is, well, scary. Needs real tuned ports and internal absorption badly.
My point is/was that by todays standards, nothing can be left as it was, except possibly the shape of the thing...
Those who use these things in the home are looking for "high efficiency" so that they can use wonderful sounding low power DHT tubes... that makes the old A-7 an obvious choice.
Which btw is partially how this project came to be.
My customer wanted a system like mine, without quite as much expense. Mine being Quadripole subs, 15" midbass, and horns from <300Hz. up, biamped. Tri-amped might even be better, but it is biamped. So the question was how to meet 300Hz horns in a single package?
A-7s looked like a way to go.
The cabs are available pretty inexpensively... as long as you don't consider the cost of bringing them up to snuff!!
Given that we're coming in at 300Hz. the "150Hz" front semi horn loading on the A-7 front will have just a slight effect - I measured it at ~3dB, and I use an alien technology derived super sharp xover that drops it like a stone at ~275Hz. Drops like a stone being on the order of -30db @300Hz. So meeting the horn is not difficult...
Given that I'm putting in a lower efficiency (than the usual Altec), wider bandwidth JBL driver, that in simulation does 30-32Hz flat and that we do not mind using a high power amp for the bottom end, the combination with the retuned (actually tuned), stiffened, damped cabinet with the horn on top should approximate my "reference" system nicely. And, exceed 99% of all commercial speakers in a fairly straightforward two peice system... one that can be biamped too.
But given the grief of the redo, it would have been likely faster and better to start from scratch built, even copying the A-7.
Of course, improving the design wouldn't be too difficult...
_-_-bear
Yeah, nice. I think I've seen pix of these before, and others like that in France... I have a few copies of Revue De Son here...
What did you put on the rear of the curved horn sections to stiffen them up? I haven't committed to anything yet, but by next weekend it will be done!
Cal and rcavictim, etc...
No this is not the first pair I have dealt with.
It is the first pair that I have been asked to rebuild and include in a system for the home! :_)
Used many and put drivers into many for PA use... imho they always sounded like ca-ca, but back in the day there were few if any other choices around! And it is amazing the abuse they put up with...
The cast aluminum horns are awful, imho.
The folks who persist in using them, I dunno about.
Around here we use <300Hz. horns for home application.
As I mentioned before, nothing you can do with a stock Altec driver will get you below 50Hz - and the stock "port" is "untuned" and lets so very much midbass through it is, well, scary. Needs real tuned ports and internal absorption badly.
My point is/was that by todays standards, nothing can be left as it was, except possibly the shape of the thing...
Those who use these things in the home are looking for "high efficiency" so that they can use wonderful sounding low power DHT tubes... that makes the old A-7 an obvious choice.
Which btw is partially how this project came to be.
My customer wanted a system like mine, without quite as much expense. Mine being Quadripole subs, 15" midbass, and horns from <300Hz. up, biamped. Tri-amped might even be better, but it is biamped. So the question was how to meet 300Hz horns in a single package?
A-7s looked like a way to go.
The cabs are available pretty inexpensively... as long as you don't consider the cost of bringing them up to snuff!!
Given that we're coming in at 300Hz. the "150Hz" front semi horn loading on the A-7 front will have just a slight effect - I measured it at ~3dB, and I use an alien technology derived super sharp xover that drops it like a stone at ~275Hz. Drops like a stone being on the order of -30db @300Hz. So meeting the horn is not difficult...
Given that I'm putting in a lower efficiency (than the usual Altec), wider bandwidth JBL driver, that in simulation does 30-32Hz flat and that we do not mind using a high power amp for the bottom end, the combination with the retuned (actually tuned), stiffened, damped cabinet with the horn on top should approximate my "reference" system nicely. And, exceed 99% of all commercial speakers in a fairly straightforward two peice system... one that can be biamped too.
But given the grief of the redo, it would have been likely faster and better to start from scratch built, even copying the A-7.
Of course, improving the design wouldn't be too difficult...
_-_-bear
Bear,
It sounds like you've dealt with the problem and actually improved the system as well. How about some pictures?
BTW; I just about fell over when I read Cal's posting, asking if you're familiar with A-7's.
To any that aren't familiar with Bear, he's a seasoned veteran. I used to enjoy his contributions on the old Bass List. While I didn't always agree with him (most of the time I did), his opinions aren't to be taken lightly as they're usually based on experience (lots).
Bear, as I haven't seen you posting here before, or perhaps I'm coming down with a bad case of "Old Timer's Disease", I hope to read more of your contributions.
Best Regards,
TerryO
It sounds like you've dealt with the problem and actually improved the system as well. How about some pictures?
BTW; I just about fell over when I read Cal's posting, asking if you're familiar with A-7's.
To any that aren't familiar with Bear, he's a seasoned veteran. I used to enjoy his contributions on the old Bass List. While I didn't always agree with him (most of the time I did), his opinions aren't to be taken lightly as they're usually based on experience (lots).
Bear, as I haven't seen you posting here before, or perhaps I'm coming down with a bad case of "Old Timer's Disease", I hope to read more of your contributions.
Best Regards,
TerryO
Hey guyz,
TerryO, I post here from time to time... not too much in this area, more in the tube, ESL and the Soylent State sections. And then not all that often, time is my enemy! No chance to deal with Audioasylum, too too too much going on to keep up with that place, and low S/N by comparison, imho. Been on since 2002...
What happened to the basslist? Hmmm... am I not subcribed to its successor? <scratches head>
Pictures? sure. Coming soon enough. They're NOT DONE yet!!
I'll be putting some pages up on my website about it, and will link 'em up here once I do. I promise. Along with the story and some results... which had best be good, or else!!
_-_-bear
TerryO, I post here from time to time... not too much in this area, more in the tube, ESL and the Soylent State sections. And then not all that often, time is my enemy! No chance to deal with Audioasylum, too too too much going on to keep up with that place, and low S/N by comparison, imho. Been on since 2002...
What happened to the basslist? Hmmm... am I not subcribed to its successor? <scratches head>
Pictures? sure. Coming soon enough. They're NOT DONE yet!!
I'll be putting some pages up on my website about it, and will link 'em up here once I do. I promise. Along with the story and some results... which had best be good, or else!!
_-_-bear
Hey Bear, yeah - building from scratch might be easier.
I hope to do so, some day.
The goop we used on the back of the horn was tar - and IIRC the brand was "Blackston" (English) was meant for sound deadening, such as in cars. It's a non hardening tar. There should be plenty of products like it on the market these days.
I put on a pretty thick coat, making sure to get it well into the kerfs.
Though I've hear many bass boxes that where bigger and better built, I've never heard one that I liked better than those "Gussied-up" A7. Certainly a lot of that has to do with the driver, tuning and damping, too.
I hope to do so, some day.
The goop we used on the back of the horn was tar - and IIRC the brand was "Blackston" (English) was meant for sound deadening, such as in cars. It's a non hardening tar. There should be plenty of products like it on the market these days.
I put on a pretty thick coat, making sure to get it well into the kerfs.
Though I've hear many bass boxes that where bigger and better built, I've never heard one that I liked better than those "Gussied-up" A7. Certainly a lot of that has to do with the driver, tuning and damping, too.
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