I don't know how it was born , but probably understand that you mean it was designed for cinema . And Yes I think it is . I heard them for the first time in the Koninklijk Theater Carré in Amsterdam and was so impressed that those "little" speakers could fill such a large theather .THANKS.
It make sense ...
does it was borne for sonorizing usa cinema??
mine friend has a room of 5,6 x 8,5 metres....
cheers
Your mates room is to small . Should be at least 12 meters long after the front of the speaker . ( Oh Oh I probably have to explain this to the critics here )
Cheers ,
Rens
To go lower all you need to do is close up the ports a bit. It's not a hard modification. And look - we are on DIY Audio forum!
Most of the Altec cases also are in need of some serious bracing, but the ports are the first thing to work on. That said, in the size room you friend has, and wanted just a subwoofer, there are better ways to go than an A7.
So, are you trying to get the VOT to go lower, or add a sub??
I was able to get the VOT to go lower, but had to use a different driver, and replace the open "reflex" area with a closed board that had actual tuned ports. There was some loss of reference sensitivity. Not that much, but some. This is a heretical approach.
It is critical to understand that the front loaded horn on the driver causes a massive tip up in the lower mids. The goal was to make the speaker system better in the *voice range* (the main thrust of the design) and to meet the sensitivity of the horn as best as possible. Another way to look at it is to see it as an attempt to maximize the SPL vs power input. Amps were typically 30-60watts when it was designed.
So, in doing a hi-fi implementation one has to deal with the lower mid horn tip up issue. That's part of the reason the bass sounds a bit light.
I was able to get the VOT to go lower, but had to use a different driver, and replace the open "reflex" area with a closed board that had actual tuned ports. There was some loss of reference sensitivity. Not that much, but some. This is a heretical approach.
It is critical to understand that the front loaded horn on the driver causes a massive tip up in the lower mids. The goal was to make the speaker system better in the *voice range* (the main thrust of the design) and to meet the sensitivity of the horn as best as possible. Another way to look at it is to see it as an attempt to maximize the SPL vs power input. Amps were typically 30-60watts when it was designed.
So, in doing a hi-fi implementation one has to deal with the lower mid horn tip up issue. That's part of the reason the bass sounds a bit light.
You can tell your friend - from me - that's a mistake.
He can make new, smaller ports by just replacing one board on the front. He can keep the original board if he ever wants to go back to stock. Internal bracing and damping can only help, not hurt - and it won't be seen.Have him look here - I built this pair in 1987 under the guidance of Mr. Hiraga.
MELAUDIA :: écoute Revue du Son - juin/juillet 2005
No ****! As soon as I saw that I had to go look in my speaker room to make sure I hadn't just forgot about it.
Funny thing is, I could just about dupilcate that with product on hand.
Pano, can you post the phase response with the amplitude response you posted earlier?
I notice that my A7 cabs have several phase rotations below 200 Hz. I suspect that below 200 Hz, most of the sound comes from the port. I haven't made any changes to the ports yet.
I find it to be quite uneven through the 100-200 Hz region and the sound lacks punch. Could be the room, but it is not the same with other speakers. I suspect it is either the A7 cab, or the drivers, which are old Alnico Altecs.
I notice that my A7 cabs have several phase rotations below 200 Hz. I suspect that below 200 Hz, most of the sound comes from the port. I haven't made any changes to the ports yet.
I find it to be quite uneven through the 100-200 Hz region and the sound lacks punch. Could be the room, but it is not the same with other speakers. I suspect it is either the A7 cab, or the drivers, which are old Alnico Altecs.
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