Greetings all,
I have been thinking about rebuilding the original Unity with the improvements disclosed in the Synergy patent, and while doing some further reading, I have discovered Chris' (Cask05) approach towards MEH. Since I have found at least some of his arguments persuasive, I have been contemplating to try his approach.
I recalled that I have a pair of Altec 288C albeit without diaphragms, and since I know that some people on this forum are Altec affectionados, I decided to solicit opinion about suitability of the driver for such a project.
1. Are any of the aftermarket diaphragms worth it, or is the best option to buy from Great Planes Audio?
2. I understand that there is no Be diaphragm for the Altec, but I was wondering if any such diaphragm would have proper diameter and radius to be adapted to fit?
3. Since I have no information about the driver's history, how do I ascertain the condition of the AlNiCo magnet? Or would it be preferable to send it to Great Planes Audio for re-magnetization?
4. What would be a frequency range (including compensation) to run the driver without strain given appropriate horn/wave-guide?
Regarding the horn/waveguide, I am lucky not be restrained by WAF. However, since the K-402 used by Chris is not readily available, is there a ready-made alternative or something that could be modified, e.g., by extending the contour to appropriate size? Even if the alternative would not have the right entry diameter, I can make or have made an adapter.
Lastly, if it would appear from your experiences, that the either the Altec and/or horn/wave-guide is not suitable, given the Altec's positive reviews, what would be a good horn/wave-guide to try? I was quite enamored with my friends Yuichi Arai A290 horn, but I also read that the TAD TH-4003 is quite an improvement. Although I understand that there used to be plans published on the Internet I was not able to find them so if anyone has them and would be willing to share, I would appreciate it.
Kindest regards,
M
I have been thinking about rebuilding the original Unity with the improvements disclosed in the Synergy patent, and while doing some further reading, I have discovered Chris' (Cask05) approach towards MEH. Since I have found at least some of his arguments persuasive, I have been contemplating to try his approach.
I recalled that I have a pair of Altec 288C albeit without diaphragms, and since I know that some people on this forum are Altec affectionados, I decided to solicit opinion about suitability of the driver for such a project.
1. Are any of the aftermarket diaphragms worth it, or is the best option to buy from Great Planes Audio?
2. I understand that there is no Be diaphragm for the Altec, but I was wondering if any such diaphragm would have proper diameter and radius to be adapted to fit?
3. Since I have no information about the driver's history, how do I ascertain the condition of the AlNiCo magnet? Or would it be preferable to send it to Great Planes Audio for re-magnetization?
4. What would be a frequency range (including compensation) to run the driver without strain given appropriate horn/wave-guide?
Regarding the horn/waveguide, I am lucky not be restrained by WAF. However, since the K-402 used by Chris is not readily available, is there a ready-made alternative or something that could be modified, e.g., by extending the contour to appropriate size? Even if the alternative would not have the right entry diameter, I can make or have made an adapter.
Lastly, if it would appear from your experiences, that the either the Altec and/or horn/wave-guide is not suitable, given the Altec's positive reviews, what would be a good horn/wave-guide to try? I was quite enamored with my friends Yuichi Arai A290 horn, but I also read that the TAD TH-4003 is quite an improvement. Although I understand that there used to be plans published on the Internet I was not able to find them so if anyone has them and would be willing to share, I would appreciate it.
Kindest regards,
M
Colour me stupid. What is MEH?
affectionados. I like it
I had my 288's redone with an 8Ω aluminum diaphragm by GPA and yes, you will want it re-magnetized. There are these kind of places around the globe that can handle this as it's a common driver from years gone by so location may be your decider.
New diaphragms need an adapter kit so make sure they know that before sending them off.
They used to mount the 288 to a 300Hz horn but I would think 500 and up is a good bet for your high pass. As far as horns go, everyone has different tastes so I won't try and help there. Lots of smart people here can give better advice than me.
affectionados. I like it
I had my 288's redone with an 8Ω aluminum diaphragm by GPA and yes, you will want it re-magnetized. There are these kind of places around the globe that can handle this as it's a common driver from years gone by so location may be your decider.
New diaphragms need an adapter kit so make sure they know that before sending them off.
They used to mount the 288 to a 300Hz horn but I would think 500 and up is a good bet for your high pass. As far as horns go, everyone has different tastes so I won't try and help there. Lots of smart people here can give better advice than me.
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Hi Cal,
thank you for the reply. MEH stands for "Multiple Entry Horn", used by some to distinguish from the usually used Unity/Synergy horn architecture created by Tom Danley.
I do understand that different people have different tastes, maybe a better term would be list of drivers with 1.4 inch throats that might work because as I understand it, some horns/wave-guides do not work well with the old style drivers.
Kindest regards,
M
thank you for the reply. MEH stands for "Multiple Entry Horn", used by some to distinguish from the usually used Unity/Synergy horn architecture created by Tom Danley.
I do understand that different people have different tastes, maybe a better term would be list of drivers with 1.4 inch throats that might work because as I understand it, some horns/wave-guides do not work well with the old style drivers.
Kindest regards,
M
If you want to make your own horn/waveguide and have a table saw (and time to make a saw sled and all the cuts), you can use my spreadsheet for that. Not as smooth a curve as a molded horn like the K402, but works pretty well (and you can make it as large as you want).
http://libinst.com/SynergyCalc/Synergy%20Calc%20V5.pdf
http://libinst.com/SynergyCalc/Synergy%20Calc%20V5.pdf
"M"
One can sort through POOH's HLCM thread and find scads of excellent info on mating Altec 288's to various horns.
The following pics are of POOH's Altec 288G's mated to 3 different horns.
- This 288G was fitted with a brand new GPA diaphragm.
One can see that the 288 dies after about 13K ( but is good to about 500hz depending on the loading of the horn ).
I listen through Altec 288-8K's / EH500 radials ( I have for about 15 years now ) and don't plan on changing any time soon.
I run a Fostex tweeter ( once in a while ) when I think I need a bit more UHF ( though I can't hear over 13K ).
Your ancient 288C's would need to be remagged ( as well as have new diaphragms properly fitted ) to be playable.
One can sort through POOH's HLCM thread and find scads of excellent info on mating Altec 288's to various horns.
The following pics are of POOH's Altec 288G's mated to 3 different horns.
- This 288G was fitted with a brand new GPA diaphragm.
One can see that the 288 dies after about 13K ( but is good to about 500hz depending on the loading of the horn ).
POOH said:
I listen through Altec 288-8K's / EH500 radials ( I have for about 15 years now ) and don't plan on changing any time soon.
I run a Fostex tweeter ( once in a while ) when I think I need a bit more UHF ( though I can't hear over 13K ).
Your ancient 288C's would need to be remagged ( as well as have new diaphragms properly fitted ) to be playable.
Other than the obvious vintage horns designed for the 288 [311-60 or 90 best bet] and short of DIY, cinema sound horns are your best bet with [probably] custom made 1.4" - 2" 'rubber throat' adapters, EQ'd to 'taste'.
Don't forget to add some form of damped end correction to the bells to damp down reflections back to the throat.
Still are at their website: Woodcraft horn
GM
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