Can you remove the horn from the 515GHP and actually do this? Did you ever do the experiment?Originally Posted by Phil-G
515 ghps that i took out of the 816VIs were plain LF drivers. the duplex drivers i put into the 816VIs were out of a pair of 9864s. the horn is not permanently mounted to the driver. the front brackets hold i in place. the 9864 is made to be biamped. when i tried them i had 2 amps one with the treble up and bass down. and the other bass up treble down. considering that,,, it sounded fairly good out in my back yard.
Sonic Barbarian
Is there a diaphragm/cd with the horn? How does it even work?515 ghps that i took out of the 816VIs were plain LF drivers. the duplex drivers i put into the 816VIs were out of a pair of 9864s. the horn is not permanently mounted to the driver. the front brackets hold i in place. the 9864 is made to be biamped. when i tried them i had 2 amps one with the treble up and bass down. and the other bass up treble down. considering that,,, it sounded fairly good out in my back yard.
just like 604/5s. they just use one magnet
Sonic Barbarian
They're built on what Altec termed "The Engine". Both HF and LF sections share a single magnet and structure much like a Tannoy dual concentric. The HF section is large format based on the 288/299. The GPA 212-8A duplex is built on the same principle.
The 604/5 uses 2 entirely separate magnets and structures mechanically attached to each other.
If you open the image in full resolution the cutaway drawing shows the engine in great detail.
http://www.lansingheritage.org/image...9864/page1.jpg
Not all vegetables make good leaders.
Well, I drove to Evansville today and bought them from a very nice guy. They are in the back of my SUV.
Cabinets were a little rough but the drivers worked. I got all of the brackets with them.
The challenge now is to determine what to do next. The obvious choice would be to biamp them using an active crossovers. I understand Altec used to offer one, as well as the equalization module. Does anyone of the forum know what the equalization module does? The type of filters used (order, alignment etc.?).
When I listened to the speakers (Without crossovers) today, the bass was sloppy and bloated. What can be done to improve that? Put the drivers into a 828 cabinet and port the 515-8GHP in a similar fashion as the 515-8G?
Looking for good suggestions.
Last edited by kwingylee; October 7th, 2019 at 08:34 AM.
Props to kwingylee for taking the plunge. Cool.
Well, pp 6 of Index of /images/altec/specs/pro-systems/9864
...mentions the 9607A plug in module.
I'd speculate it'd be the same 16pin DIM as would fit into the 1631A crossover, and probably thus that is what they were referring to.
There is one on reverb right now. Very similar is the EV XEQ-2. I'd say they were the same but have had neither - and IIRC when I looked into them the XO slopes were different - but I am a bit foggy on that.
Presumably the 9607A just sets the XO to 1000hz as they recomend - OR - it's the CD horn EQ.
one thread on the topic:
searching frequency plug-in modules for Altec 1631A or EV XEQ-2 dividing network
...but before buying anything to 'build your own from the manual instructions' , do check that the manual has the instructions. I don't think I ever found them.
I have a 9605A which I've now forgotten anything about, but it's sitting here. I may remember more tomorrow. :-)
I was collecting and tinkering with the octal plug-in XO's which fit the 9442, 9444 etc. amps.
In hindsight, I'd have gone to the dbx driverack sooner and skipped the tinkering - but then you may find yourself building/buying ganged attenuators to sit between it and the power amps, as vol controls.
1631A manual with module building instructions in second manual
ALTEC LANSING 1631A SIGNAL PROCESSING MANUAL Pdf Download.
Your neighbors called. They like your music.
Thanks gearfreak:
I am not really interested in getting the Altec 1631a, their associated modules and the built. I have a number of Electrovoice Telex ISP-100 digital crossovers that I can used. The manual indicates that the 3rd order Butterworth is the recommended alignment. You could very well be right about the CD horn type compensation, I think it will be a good place to start until I get REW running on one of my laptops so I can do portable measurements to aid in determining the proper equalization needed.
The instructions for building the 1KHz and CD horn equalization modules are in the 1631A manual section 4.8 and part 2.... if you have the 1631A and the empty modules for building them.
- - - Updated - - -
Thanks Old Guy
Last edited by kwingylee; October 7th, 2019 at 11:05 PM.
Yup, I was using the octals for the 24db slopes, kinda passed over the 1631a/XEQ-2. What I could not find then - and still cannot - is the CD Horn EQ recipe. I don't see it there in 4.8. No worries though, have moved on from them too.
So how are the engines coming along?
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