This is an excellent and most informative video. It's exactly what I wanted to know and have been researching. I found out I have the valuable diaphragm in 1 of mine. I am going to replace them with a more modern one and keep the old one safe. Thanks again. Edit: So the more modern and more available (relatively) 16 ohm diaphragms would be a correct replacement for a 288B with modified spade connectors and shorter screws?
I have a pair of New old stock 288,c that came from. The estate of a broadcast engineer , the red seal on the one screw is unbroken , does it devalue to break the seal to prove they are original phrams
Bones of the dinosaurs of sound, meant to fill larger theaters with fine memories to go with the excellent pictures of the time. We are in a comic book culture and burn-through masses of plastic imitations, replacing careful engineering with computer guesses and increasingly full landfills made from these mistakes. We'll have to jump off the planet and get more raw material, as we're running out of substantial, lasting solutions, due to short product life cycles. How many "speaker manufacturers" have come and gone, since the discoveries of the Bell Lab Boys?? Hmmm?
RCA PhotoPhone stuff never came with aluminum diaphragms. even the common MI-9584 series were 3" phenolic diapragms.Not much in the way of similarites to the Altec stuff.
That is most certainly true. There were a few exceptions, RCA made some Master Index listed compression drivers similar to Jensen Hypex in the 1940s using aluminum as well as some other small drivers. They also sold some smaller drivers, but those were probably made by Racon ....They begin again with aluminum again in the 1970s but those drivers were JBL design and production. RCA was so huge and prolific, it's almost impossible know all of the products they made (and if they were contracted or not!) Thank you very much for the comment and thank you for watching.
@@HiFiTown no prob,had a rather large collection of MI- theater stuff. Recent move so I decided to let it go. The theater stuff was all excellent design but with the parameters set by design group of an HF upper of 7Khz some of the items sought need help in the upper octaves to be considered HiFi. One exception I make is the MI-1428 with it's 4" phenol cone diaphragm as a midrange unit which is a "goose pimples" with female vocals in a good three way setup from about 300-5000 hz. As you suggested,anything alum was either subbed out or rebranded other manufacturers pieces. There are a pair of 30 ohm MI-9449 woofers around here somewhere but the rest is gone.
I don't see how it's possible for the GPAs to be constructed of the same materials exactly - - and I don't believe the coils could perform the same (GPA would be thicker) or former (GPA would be Kapton similar) and the aluminum it's self would be of a different grade and temper (causing different breakup patterns) . The materials are the not same due to design constraints, availability, manufacturing process (this has changed greatly over the past 60 years) requiring higher program wattage of this century's solid-state amplifier era. Sure, it's possible for different materials to perform similarly, but if weights or flexibility (rigidity) differ at all, the laws of physics would dictate for this, not to be likely in the least. Those who say the GPA diaphragms sound the same may be speaking subjectively - - But, if there are measurements and SPL charts, we could certainly take a look. When presented with test results, I would caution that such sensitive tests need to be done in careful A/B conditions, and only minor f, variations of rooms, mic placement or driver, magnet strength, (or hundreds of other minor parameters would cause the performance characteristics to change. When you can compare SPL charts to one another - - drivers usually perform grossly the same - - it's the Little Peaks, and dips that you have to watch out for. Somewhere hidden in those peaks and dips of the non-linear metal "breakup" - - the harshness of modern diaphragms will hide to get your ears.
They made those, certainly. I have seen many. The "Maestro" was not a logo they used for long. It appeared on products beginning around 1960 and kind of disappeared inside the decade. I have seen it on replacements as well. Take a look at the outer clamp ring and compare it to some in the video, that should give you an idea on it's age 😉
Hello, very rare now, need to check stock. You can email me, salesdesk@hifitown.com -- I will check to see what is available. 288C is more common, and also very nice sounding.
Early learned a lot from his dad, Walt Bender. If he says something about how something sounds, you can take it to the bank.
Thanks Bob. Great to hear from you and wishing you happy pursuits in all of audio!
This is an excellent and most informative video. It's exactly what I wanted to know and have been researching. I found out I have the valuable diaphragm in 1 of mine. I am going to replace them with a more modern one and keep the old one safe. Thanks again.
Edit: So the more modern and more available (relatively) 16 ohm diaphragms would be a correct replacement for a 288B with modified spade connectors and shorter screws?
Yes, I believe so. The threads are US, so adjust length as needed, using non-magnetic brass.
The 288B came in a 16 Ohm version too - I have a pair and can send you photos if you like
Ike Carumba Yes, they did, have seen many.
I have a pair of New old stock 288,c that came from. The estate of a broadcast engineer , the red seal on the one screw is unbroken , does it devalue to break the seal to prove they are original phrams
very precious 288c i wish i had it, it's second hand open it carefully to check
Bones of the dinosaurs of sound, meant to fill larger theaters with fine memories to go with the excellent pictures of the time. We are in a comic book culture and burn-through masses of plastic imitations, replacing careful engineering with computer guesses and increasingly full landfills made from these mistakes. We'll have to jump off the planet and get more raw material, as we're running out of substantial, lasting solutions, due to short product life cycles. How many "speaker manufacturers" have come and gone, since the discoveries of the Bell Lab Boys?? Hmmm?
RCA PhotoPhone stuff never came with aluminum diaphragms. even the common MI-9584 series were 3" phenolic diapragms.Not much in the way of similarites to the Altec stuff.
That is most certainly true. There were a few exceptions, RCA made some Master Index listed compression drivers similar to Jensen Hypex in the 1940s using aluminum as well as some other small drivers. They also sold some smaller drivers, but those were probably made by Racon ....They begin again with aluminum again in the 1970s but those drivers were JBL design and production. RCA was so huge and prolific, it's almost impossible know all of the products they made (and if they were contracted or not!)
Thank you very much for the comment and thank you for watching.
@@HiFiTown no prob,had a rather large collection of MI- theater stuff. Recent move so I decided to let it go. The theater stuff was all excellent design but with the parameters set by design group of an HF upper of 7Khz some of the items sought need help in the upper octaves to be considered HiFi. One exception I make is the MI-1428 with it's 4" phenol cone diaphragm as a midrange unit which is a "goose pimples" with female vocals in a good three way setup from about 300-5000 hz. As you suggested,anything alum was either subbed out or rebranded other manufacturers pieces. There are a pair of 30 ohm MI-9449 woofers around here somewhere but the rest is gone.
How can I sell a pair
I want to buy 288B or 288 hoollywood do you sell it? please !
How different is GPA 288 16ohm diaphragm? Many people agreed that there is no difference in sound or measurement..
I don't see how it's possible for the GPAs to be constructed of the same materials exactly - - and I don't believe the coils could perform the same (GPA would be thicker) or former (GPA would be Kapton similar) and the aluminum it's self would be of a different grade and temper (causing different breakup patterns) . The materials are the not same due to design constraints, availability, manufacturing process (this has changed greatly over the past 60 years) requiring higher program wattage of this century's solid-state amplifier era.
Sure, it's possible for different materials to perform similarly, but if weights or flexibility (rigidity) differ at all, the laws of physics would dictate for this, not to be likely in the least.
Those who say the GPA diaphragms sound the same may be speaking subjectively - - But, if there are measurements and SPL charts, we could certainly take a look.
When presented with test results, I would caution that such sensitive tests need to be done in careful A/B conditions, and only minor f, variations of rooms, mic placement or driver, magnet strength, (or hundreds of other minor parameters would cause the performance characteristics to change.
When you can compare SPL charts to one another - - drivers usually perform grossly the same - - it's the Little Peaks, and dips that you have to watch out for.
Somewhere hidden in those peaks and dips of the non-linear metal "breakup" - - the harshness of modern diaphragms will hide to get your ears.
I have a pair of the 288c and the diaphragm is stamped with the altec meastro logo its the only one I've seem any info would be appreciated
They made those, certainly. I have seen many. The "Maestro" was not a logo they used for long. It appeared on products beginning around 1960 and kind of disappeared inside the decade. I have seen it on replacements as well. Take a look at the outer clamp ring and compare it to some in the video, that should give you an idea on it's age 😉
@@HiFiTown i have 3 complete 1005b with throats and the 288c drivers
I'm looking to sell them
If your interested let me know
tuyệt vời quá bạn
I want to buy 288B or 288 hoollywood do you sell it? please
Hello, very rare now, need to check stock. You can email me, salesdesk@hifitown.com -- I will check to see what is available. 288C is more common, and also very nice sounding.