CD Horn EQ Modules

[cclark65]

I have finally aquired the modules I need to install on my 9444 amps that will enable the CD Horn EQ to be resident on the amps since my crossover doesn't have it.

I have 2 flat modules, and 2 modules labeled 9602. Upon opening them, they are just a set of resistors from what it appears.

I am looking for information to convert these to a different horn/driver combination. Specifically the 9605 and 9607 for running the 906 drivers on MRII594 and eventually MRII564 horns (When I get a few more...anybody got some laying around for sale or trade?! I have 4 now, looking for 4 more eventually )

I have the manuals and stuff for the 1632 equalizer that tells me what module to use for what combination, but I haven't got the information to convert them over.

[cclark65]

Let me make that a little clearer.

I have some of the 15595A modules. I will put them on the amps pretty much only to use the horn eq.

1 of them has a flat dip module inside, 2 of them have 9602 modules.

I want to convert the dip modules to 9605 for now, but 9607 in the future when I get different horns going.

If I can bypass the internal crossover point, then I'll do that also.

Does anybody know if the crossover at 315 will cause a problem when I have it crossed over at 1200 before the input of the amp?

Thanks!

PS - I am way happy to see the board back online!

[cclark65]

ok, so I think I might have had a stupid moment a when I first looked at the manual for the 1632 crossover. It does list how to make the modules for what I want. Sorry for posting that I needed the information when I had it right in front of me, but just didn't read it thorougly enough. The chart is on the same page as the low frequency submodule talk, and I assumed it was for them. Turns out the chart is for the CD Horn EQ on the next page!

[cclark65]

I just love this conversation with myself, so I might as well continue it :-)

I have the required resistors to make the CD Horn EQ modules that I need for my drivers and horns.

However, I don't want the crossover part at all, is there a way to just bypass the crossover and only use the EQ module?

I'll continue to research it and if I find it out, I'll post it here. However, if somebody else knows, it would be much appreciated!

[cclark65]

ok, I finally got the resistors in and converted the modules to the correct format for my horns.

Now I have plugged one of them into my Anniversary Series 9442 amp that I use for my horns.

I put a scope on the input and output of the amp to check for differences. Lo and behold, the input and output are now out of phase. Not by 180, but almost. If it were a perfect 180, then I would just invert the input and be done. However, there is also noise on the output of the amp also, were before I had a clean sine save in time with each other, now I have inverted sine waves with noise on the output!?

I haven't even hooked it up to a speaker yet, but according to the scope, it's not going to be nice :-(

I post video's of the scope here if anybody is interested in checking them out. They are barely over 1 meg, so download isn't horrible. Just 5 second clips of the waveform. I adjusted the scope so that you could see the tails of each form also.

http://www.acsnet.com/~cclark/altec

Can anybody give me any clues as to what's happening here?

Thanks!

[Todd W. White]

Hi Charles,

You know, I never used those CD Horn EQ modules in all of the Altec systems I designed and/installed, and that's a LOT of 1631's and Anniversary Series amplifiers!

When they came out, we contractors wanted to know "Why?"

Altec's response was that this was a response to the acoustical consultant crowd, who would not believe that the Altec Mantaray's and driver combinations didn't have all of the problems inherent in the JBL and EV stuff (even though they DON'T).

So, the consultants wanted CD Horn EQ, they GOT CD Horn EQ.

It was, IMHO, a marketing decision - I never thought they helped the sound: when I tried them the first few times, they sounded AWFUL, so I chunked 'em.

[cclark65]

I have never really thought I needed them either, and lots of people compliment on the sound all the time, but I have read and researched, and Altec made them, so I figured I should at least see what all the talk is about.

I value your opinion greatly, and I am sure I'll think the same way, but I have driven myself so far into this project and so much research, I have to at least get it finished, even if I do end up not using it.

My next step is to find a 1200 (or in that range) module and try it out without my other crossover. It's wierd that if I run just the crossover module, I get no distortion, and if I run just the outboard crossover, I get no distortion, but when I run them in series in order to put the horn eq inline, it distorts. I am guessing it's a phase anomaly of some sort by going through both crossovers. The first one is at 1200, and the module I have is 315. I figured that the 315 wouldn't even be an issue since the signal is over 1200 already before it gets there, but evidently I am wrong...now I need to find out why. I wish I was one of those people that didn't care to figure it out, but it'll bug me till I do get it.

I did hook it up to a driver since the last post, and I can definitely hear what I am seeing on the waveform. (I purposely made the waveform move like that to make it easy to see the phase shifting)