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Quantum 2 hybrid project

I was told some models had the rear firing emit and some did not. It would be very easy to add anytime structurally. The problem is adding it to the 3 front's and wiring it out of phase without dropping the resistance too low, and adding an on/off switch if you didn't like it. Which turning it off changes the resistance and crossover point of the 3 fronts. If anybody has the technical knowledge of how I could do it, please let me know and I'll add it now. I have the crossover plans my software designed for the front 3 emit's if that helps.
 
wwiztab said:
I was told some models had the rear firing emit and some did not. It would be very easy to add anytime structurally. The problem is adding it to the 3 front's and wiring it out of phase without dropping the resistance too low, and adding an on/off switch if you didn't like it. Which turning it off changes the resistance and crossover point of the 3 fronts. If anybody has the technical knowledge of how I could do it, please let me know and I'll add it now. I have the crossover plans my software designed for the front 3 emit's if that helps.
Click to expand...

Why not just wire in a level pot instead of an on/off switch? That way no affect on the three front EMITs.

Tweeters to the inside, for sure. I've tried it both ways. The hi-hat shouldn't sound like it's coming right from the right speaker or, even worse, outboard of it. It should be located some place in the sound stage between the right speaker and dead center. I've had the ribbons to the outside on my Maggie MG-III's and preferred that, but that's only because they put off so much rear wave information they can pull it off. Front firing EMITs to the outside might image, but they won't populate the sound stage correctly.

- Michael
 
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So, the same type of pot like Infinity uses on everything, with the resistor?

Would I be able to keep the current x-over design for the 3 front's then wire in the back out of phase in parallel with it's own crossover? That would drop the impedance though right?

I'll have to wire it up and hook it up with the software again to verify impedance.
 
Finally had some time to start the finishing process. Not done yet, but it's a start. I have lots of time off the next three weeks so, I should have these babies singing by the new year.
 

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Couldn't help it, had to set the drivers in just to look. Crossover work to complete, then mounting the drivers, then finally listening. I'll make the grilles sometime, not in a hurry though on those. I did add a Kappa K Emit to the back also.
 

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Busy summer and just got done moving. I will have some time soon to work on the crosovers for the tweeters and poly domes. I will be visiting PS Audio soon and hopefully talking to Paul. I'd like to see if he might talk to Arnie about these and maybe help me out with getting the crossovers right the first time. Then I'll ask Paul if he'd be willing to test them out in listening room 2. Maybe it's a long shot but it never hurts to ask. I'd like to sell them when they are completed and move on to building a set of modified QLS - 1's.
 
There is only one thing I can see with this GREAT speaker project, that has me wondering a bit...

You put the EMITs spaced apart, so that the total length of the three from top to bottom might be more like the original Quantum 2s. Okay, makes sense in a way, given the aims of the design, but thinking of how sound waves propagate and cancel, and how line-array speakers work, wouldn't it have been better to have bunched the three EMITs closer together, even if the total length of the EMIT array would be shortened?

Of course, the EMITs in the original Quantums were themselves longer, and butted up against each other (as closely as Infinity could get them). I'm certain that was deliberate, and was done to create a "line array" effect that would act like a single ribbon, without "lobing" and consequent wave cancellations.

Or did you do some kind of calculation/measurement, that said they'd be okay at this particular spacing?

Don't take this as a criticism. There may well be great wisdom in your decision, and I'm "all ears" to learn something here. But personally, I would have moved the EMITs together, barring a calculation that says your spacing would work as well. Am I missing something?
 
I am hoping to ask that question to the creator of Infinity in the very near future. I am planning a visit to PS Audio in Boulder and Paul McGowan is in contact with Arnie Nudell often. Maybe Paul would do me a favor and ask him to help me with the crossovers and ask your question. I can modify and stack the emits if necessary. I could add an 1/8" or 1/4" piece of cherry and reconfigure the emits and polydomes.
 
Arkay said:
There is only one thing I can see with this GREAT speaker project, that has me wondering a bit...

You put the EMITs spaced apart, so that the total length of the three from top to bottom might be more like the original Quantum 2s. Okay, makes sense in a way, given the aims of the design, but thinking of how sound waves propagate and cancel, and how line-array speakers work, wouldn't it have been better to have bunched the three EMITs closer together, even if the total length of the EMIT array would be shortened?

Of course, the EMITs in the original Quantums were themselves longer, and butted up against each other (as closely as Infinity could get them). I'm certain that was deliberate, and was done to create a "line array" effect that would act like a single ribbon, without "lobing" and consequent wave cancellations.

Or did you do some kind of calculation/measurement, that said they'd be okay at this particular spacing?

Don't take this as a criticism. There may well be great wisdom in your decision, and I'm "all ears" to learn something here. But personally, I would have moved the EMITs together, barring a calculation that says your spacing would work as well. Am I missing something?
Click to expand...

So I was able to get this question answered from Paul McGowan. He remembers Arnie saying that the Emits needed to be as close together as they could get. Looks like I will need to modify a little, which won't be a big deal. I'm glad you asked the question Arkay, thank you very much.
 
Cabinets are sitting in my shop. I will have to modify the cabinets for sure to get EMITS closer together. Right now I'm starting the process of building my house. I'm going to be the general contractor on it and hopefully will have it done by Christmas 2015. Guess what's driving the basement floor plan? Yep, a listening room to sit and enjoy those when I'm all done (among hopefully many other vintage Infinity models).
 
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