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Chorus ii - Replacing passive radiator


Monkeybuddy

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@moray james - would love your input regarding this topic.

 

I asked the Klipsch rep about using the passives from another speaker i.e. Forte, but he didnt really give me a clear answer and it seemed as if he were leaning towards 'No'.  I'll research this possibility a bit more, but perhaps someone else has already?

 

It was also suggested to me that i could simply remove the magnet from the Woofer (the one i removed from the passive radiator location) , and use that as the passive.  Is this feasible?

 

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42 minutes ago, Monkeybuddy said:

It was also suggested to me that i could simply remove the magnet from the Woofer (the one i removed from the passive radiator location) , and use that as the passive.  Is this feasible?

 

In theory, yes, but I do not believe that the Eminence 7308 woofers you would be modifying have the proper outer suspension to provide enough compliance (travel).

Ideally, you would need something with a neoprene (or similar material) rolled rubber surround like the Chorus II radiators shown in the post by wvu80.

 

Then there is the issue of tuning the cone with weight(s) to provide the proper resonance frequency.  You may need to add a plywood plug to the center tube on which you could bolt washers for weight (no more than an ounce or two)...typically starting low and working your way up.

 

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57 minutes ago, Monkeybuddy said:

It was also suggested to me that i could simply remove the magnet from the Woofer (the one i removed from the passive radiator location) , and use that as the passive.  Is this feasible?

 

No - that doesn't work. The suspension of the passive radiator is much softer than the suspension of the active driver. This is how you tune the resonant frequency. The suspension of an active driver is way too stiff (and not hard to model actually).

 

I would sooner use the KD-15 passive from the Forte III, but I think the risk is a design that is tuned too low and too narrow. Do you think you could get Klipsch to share the T/S parameters of the KD-15? Without that, we can't know how well it'd work in the Chorus II cabinet.

 

If simply speakers has the correct recone kit, then you could use the recone kit with the existing driver frame and take off the magnet. That would probably be the second cheapest route.

 

Btw, I checked my notes. The port holes were 3" in diameter and 0.75" deep (the thickness of the MDF). A passive radiator and normal port provide the same acoustic function. If you have the ability to cut circles, then this will by far be the easiest solution - and it's completely reversible should you decide to change your mind. Just use the same screws that were holding the passive radiator in place.

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1 hour ago, DrWho said:

No - that doesn't work. The suspension of the passive radiator is much softer than the suspension of the active driver. This is how you tune the resonant frequency. The suspension of an active driver is way too stiff (and not hard to model actually).

 

I would sooner use the KD-15 passive from the Forte III, but I think the risk is a design that is tuned too low and too narrow. Do you think you could get Klipsch to share the T/S parameters of the KD-15? Without that, we can't know how well it'd work in the Chorus II cabinet.

 

If simply speakers has the correct recone kit, then you could use the recone kit with the existing driver frame and take off the magnet. That would probably be the second cheapest route.

 

Btw, I checked my notes. The port holes were 3" in diameter and 0.75" deep (the thickness of the MDF). A passive radiator and normal port provide the same acoustic function. If you have the ability to cut circles, then this will by far be the easiest solution - and it's completely reversible should you decide to change your mind. Just use the same screws that were holding the passive radiator in place.

 

I'll look into specs for the KD-15 and report back.

 

Another thought:

 

The metal cage of the woofer and passive i removed look very similar, if not exactly the same.  Any thoughts about removing the magnet and using a recone kit  like the one in this link:

https://www.simplyspeakers.com/klipsch-speaker-passive-radiator-recone-kit-rk-klpkd15.html

 

Just realized this question was addressed in the previous post :)

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42 minutes ago, DrWho said:

No - that doesn't work. The suspension of the passive radiator is much softer than the suspension of the active driver. This is how you tune the resonant frequency. The suspension of an active driver is way too stiff (and not hard to model actually).

 

I would sooner use the KD-15 passive from the Forte III, but I think the risk is a design that is tuned too low and too narrow. Do you think you could get Klipsch to share the T/S parameters of the KD-15? Without that, we can't know how well it'd work in the Chorus II cabinet.

 

If simply speakers has the correct recone kit, then you could use the recone kit with the existing driver frame and take off the magnet. That would probably be the second cheapest route.

 

Btw, I checked my notes. The port holes were 3" in diameter and 0.75" deep (the thickness of the MDF). A passive radiator and normal port provide the same acoustic function. If you have the ability to cut circles, then this will by far be the easiest solution - and it's completely reversible should you decide to change your mind. Just use the same screws that were holding the passive radiator in place.

You don't need the parameters. All you need is me saying that the drone in the III will work in the ii. That's all. 

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2 hours ago, Monkeybuddy said:

I asked the Klipsch rep about using the passives from another speaker i.e. Forte, but he didnt really give me a clear answer and it seemed as if he were leaning towards 'No'.  I'll research this possibility a bit more, but perhaps someone else has already?

 

22 minutes ago, Chief bonehead said:

All you need is me saying that the drone in the III will work in the ii. That's all. 

There you go.

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4 hours ago, Chief bonehead said:

You don't need the parameters. All you need is me saying that the drone in the III will work in the ii. That's all. 

 

2 hours ago, DizRotus said:

@Monkeybuddy you might not realize that @Chief bonehead is Roy Delgado, an engineer at Klipsch.  If he says it will work, it will work.

 

The confidence in his reply alone sold me, but that is very reassuring to know - thank you.

 

I'm going to call to see how much they are.  Im guessing $100+ for each, not sure if they have a recone kit.  I may end up getting the Simply Speakers Recone Kit at $40/ea, removing the magnet and reconing both.  But perhaps there is something to be said about using Klipsch parts vs 3rd party?

 

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4 hours ago, DrWho said:

If you have the ability to cut circles, then this will by far be the easiest solution - and it's completely reversible should you decide to change your mind. Just use the same screws that were holding the passive radiator in place.

He wouldn't even need a router, you can buy 3" hole saws.  That would be an inexpensive, easy and elegant solution.

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6 hours ago, Monkeybuddy said:

UPDATE:

 

Spoke with a Klipsch representative who informed me they no longer carry this part/ KD-16.  He recommended a place called Simply Speakers, but it doesnt seem that they have the whole assembly - just a recone kit.  

 

I guess I'll be posting a "WTB" ad here soon...  Not sure if finding another drop-in 15" passive radiator is plausible.

Keep your eyes on eBay. Lots of Klipsch speaker elements come up for sale. I just looked and although there are none up for sale now, the situation changes daily. Be patient.

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6 hours ago, DrWho said:

 

Btw, I checked my notes. The port holes were 3" in diameter and 0.75" deep (the thickness of the MDF). A passive radiator and normal port provide the same acoustic function. If you have the ability to cut circles, then this will by far be the easiest solution - and it's completely reversible should you decide to change your mind. Just use the same screws that were holding the passive radiator in place.

 

  @Chief bonehead or anyone else who has knowledge of this - I am curious about what your opinions are regarding fabricating ports vs. passive radiators in the Chorus iis.  I think I am going to give this a shot..

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Someone else here did this to Chorus ll's besides Dr. Who..... can't think of his name. He had Chorus ll's and LaScala's that he fixed up.....did a nice job, too.

Sent from my SM-G950U using Tapatalk

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30 minutes ago, Monkeybuddy said:

 

  @Chief bonehead or anyone else who has knowledge of this - I am curious about what your opinions are regarding fabricating ports vs. passive radiators in the Chorus iis.  I think I am going to give this a shot..

If you make ports you'll end up with Chorus i's for better or worse

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43 minutes ago, SWL said:

Someone else here did this to Chorus ll's besides Dr. Who..... can't think of his name. He had Chorus ll's and LaScala's that he fixed up.....did a nice job, too.

There are several threads on porting the Ch2's.  I was thinking @Deang made some comments or offered specifics but I can't find the thread now, it was from 2013 or thereabouts.

 

For the cost of a couple of four buck 3" ports from PE if it were me I'd give it a shot as opposed to putting $200 into $200 speakers.  You could even use a variable length port to tune the bass to your taste.

https://www.parts-express.com/precision-port-psp-3ofh-3-outside-flare-for-port-tube--268-368

 

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6 hours ago, wvu80 said:

 if it were me I'd give it a shot as opposed to putting $200 into $200 speakers.  

 

I guess it would really depend on what the future plan is with these speakers. If there is ever a possibility that these might go up for sale any time in the future $200 in passives could really add to the value of these speakers, turning a $200 pair into a $600+ pair so it would be money well spent plus they would sound as intended from Klipsch. I could see using the block off plates as a temp solution but I would keep an eye out for the real thing or just bite the bullet and buy new from Klipsch, these are an investment and should be treated as such my .02 anyway.

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Got to agree, I have a pair of chorus II's and I's in my present set up. The I's have 7 inch ports and bumped a coupls notch's on bass knob. Sounds good but II's are just as tight with a little more punch. Not saying a tuned port could not sound good but still would not be an original sounding II. Got to think resell value would go down with a port. .2cents

 

 

 

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10 hours ago, Monkeybuddy said:

 

 

The confidence in his reply alone sold me, but that is very reassuring to know - thank you.

 

I'm going to call to see how much they are.  Im guessing $100+ for each, not sure if they have a recone kit.  I may end up getting the Simply Speakers Recone Kit at $40/ea, removing the magnet and reconing both.  But perhaps there is something to be said about using Klipsch parts vs 3rd party?

 

Have not used simple speakers but have hear good and bad about them. Maybe someone here has some real world experience with them. They may be a good choice but sometimes trying to save a few bucks costs more in the long run. 

 

If you get a know quality speaker right away you should have years of trouble free listening. .02

 

 

 

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2 hours ago, Ljk said:

Have not used simple speakers but have hear good and bad about them. Maybe someone here has some real world experience with them. They may be a good choice but sometimes trying to save a few bucks costs more in the long run. 

I've used them several times.  Always a good experience.

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17 hours ago, Chief bonehead said:

You don't need the parameters. All you need is me saying that the drone in the III will work in the ii. That's all. 

Saweet!

 

You should let your parts team know that....otherwise I wouldn't have cut my Chorus II cabinets apart. Although I am enjoying my 2-way setup quite a bit.

 

Unfortunately I didn't grab photos of the ports....just myself covered in the sawdust from all my free-hand routing, haha.

 

 

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