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Help with compression driver replacement on RF7 ii


gago1101

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Does anyone know how or if it is easy to take out the compression drivers on Klpisch RF7 ii's. I am trying to figure out if it will be easy or too hard to replace them.
thanks in advance

Fairly new RF7 II speakers and you would like to change the drivers? Do you know how to redo the crossover? What are you trying to gain?

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I have removed the crossovers altogether and am using an active crossover. The speakers and its 1.75" compression drivers are fine. The only thing is that I feel I am missing something in the 800-1khz zone. Not sure if it is the nature of the driver or the hump it creates at around 2khz. I is hard to see from the room response that I get below. My goal is to replace the driver with something like Fostex 1400 so I can lower the crossover point to around 650Hz instead of about 1khz that I have now.

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On the mechanical side. I can't tell from the German review's pictures whether the structure wil allow for use of another driver, screw-on or bolt on. But the review says good things about the speaker. I used a translator.

You'd have to take a close look at the horn yourself, of course. it might require taking the assembly out of the box.

It's good that you can measure things. But from the graph, I don't see much of a hump -- per the Igor quip by our buddy.

If there is a hump, I think that the room response is not accurate enough to conclude it comes from the driver, or the horn, or the box. If you take the box outside and run the test you can learn more. But even then,it could be from panel and edge effects of the box.

I see that you are running the crossover (electronic?) at 1000 Hz while Klipsch sets it at 1200 Hz. That is not too much of a difference.

However, the goal of getting the midrange horn to work down to 650 Hz seems to me to be unrealistic. Horns, even the type used in the RF will load a driver down to some effective Fc. Klipsch must have designed the crossover freq to match the Fc of the horn. Therefore, even if the Fostex has a potential output down to 650 Hz, the horn is not going to absorb it ("loading") and pass it through.

Even if this "midrange down to 650" could work, you'd have to play with the crossover in the bass box to cut it off at 650.

If you want to play with the hump, it might best be done with some sort of equalizer..

WMcD

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However, the goal of getting the midrange horn to work down to 650 Hz seems to me to be unrealistic. Horns, even the type used in the RF will load a driver down to some effective Fc. Klipsch must have designed the crossover freq to match the Fc of the horn. Therefore, even if the Fostex has a potential output down to 650 Hz, the horn is not going to absorb it ("loading") and pass it through.

Even if this "midrange down to 650" could work, you'd have to play with the crossover in the bass box to cut it off at 650.

WMcD

I bet you are right with the horn cut off. What is the model of horn used on the RF7-II. Likely not able to get down under 800hz.

On a side note, the graphs from the article are interesting - http://www.avsforum.com/t/1412510/klipsch-rf7-ii-measurements

Larger horn, lower crossover point or less rolloff on the woofers, and some additional volume in the cabinet would possibly smooth things out more. Wouldn't sound as crisp then which is likely what Klipsch was going for.

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Does the entire bezel or portion of the bezel (motor board) come off? On the driver itself, there is a shield 'can' that is hot glued to the driver, a heat gun will melt the adhesive so you can get the can off, then it's a pretty simple matter of disassembling the magnet structure, removing the old coil/ diaphram, INSPECTING AND CLEANING the voice coil gap, and reassembling with new diaphragm.

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  • 2 weeks later...

I am not trying to change the driver based on an aberration on the graph. I am merely trying to blame the bad midrange sound that I can hear to the aberration or possibly to woofer rolloff. It may just be the quality of the sound that the driver makes rather than anything else. Hence, my idea of replacing the compression driver.

The mids sound harsh, congested and lost in between the bass and the highs. It is much better with the separate amplification and electronic crossovers, but still not good. My side by side comparison is with my cheap JBL L890 speakers, which sound significantly better in the mids, clearer and more open.

The Klpisch p39f has almost the same size horn with just a larger throat. It goes down to 500hz, so I am hoping the horn will allow for the 650hz range.

I have not ventures to take the drivers out, but will be doing it soon.

Thanks for the replies!

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I was actually able to take it apart. The front frame is there to hide the screws.The driver is connected using 3 screws exactly spaced as the Fostex D1400 drive that I am looking to get. I am still trying to decide wether to pull the trigger on the Fostex $1.2K/pr or go berserk and get the TAD td-2001 drivers $3K for the pair. Will let everyone know when I get either one and install.

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  • 4 weeks later...

Just to update my original post.

I finally ended up getting a much cheaper option than Fostex or TAD, I got the Radian 475PB-8 1" Aluminum Horn Driver ($360/pr) to replace the original Klipsch K-701-G drivers found in my RF-7 ii speakers.

The removal and the replacement of the drivers was really easy, took about 20 minutes. As I had the horns out, I also ended up painting the horns gold/bronze to match the woofers and the Fostex tweeters (see attached).

First, Radians are about 50% bigger than the Klipsch in size and probably twice as heavy.

You can find the frequency responses attached to the post. There is not much difference, possibly slightly flatter response with the Radians. Also, it seems the Klpisch actually goes slightly lower down to 800hz compared to the Radians (see before & after freq responses below)

Now the sound. I am very pleased with the change. I think the vocals sound significantly more clearer and open, it is almost like a night and day change. I do not feel the congestion and harshness any more. Interestingly, the freq response cannot explain the difference in sound that I am hearing. I also spend a lot of time trying to get the speakers time aligned. After lots of impulse measurements and delay adjustments, I finally have them aligned perfectly and it sounds sublime. I can say my current setup easily bests the Mcintosh mc601 / B&W 800D combo in Magnolia by miles. Can't be happier

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