robotc

Your crossover looks great. I am really interested to hear how you find the sound from the new version. The resonance at 200Hz was definitely due to the rubber feet. At that frequency the whole enclosure was vibrating strongly. I am not sure if it would be audible when listening to music because the peak was so narrow. Removing the rubber feet went a fair way to reducing the resonance. I can post the measurements if you are interested. Are you making any measurements of your speakers? Robert

I haven't visited the forum for a while and just found your post. The only resonance that showed on the impedance plot was around 200Hz. I did a bit of investigation and found that this was the resonance of the whole enclosure vibrating on the rubber feet. I braced and damped the enclosures but I couldn't see any differences in the before and after impedance plots. However the changes made a big difference subjectively. The tweeter attenuation on the plot I posted was 10dB. This gave the flattest measured response but I felt subjectively this was too much Robert

RF3 Impedance

You're right. Klipsch have removed the specs from the Aus site and replaced them with the pictures and general description from the US site. Why have Klipsch done this??? What's the point??

CORRECTION TO CIRCUIT I was hoping this wouldn't happen but it did The polarity of the tweeter was incorrectly marked on the schematic. Here is the correct version klipsch RF3 mod.xover revised.pdf

The resistance is not critical. I modeled the crossover with the total resistance of the 1.0mH inductor plus resistor as 8.2R but an ohm difference either way shouldn't make much difference. The series LCR is there to level out the tweeter impedance at resonance. The load is 4ohms across the whole frequency range. Robert

I did some testing of foam in the horn of my RF3 speakers a while back. The results I got might not apply to the horns you are modding but the results might interest you. I decided not to use foam inside the horn because I thought it might affect the geometry too much. Instead I stuck felt on the surface covering about half the depth of the horn. I also stuck a strip of open cell foam around the outside of the mouth. The effect on the frequency response is shown in the attached graphs. The measurements are at 80cm with no crossover attached. I didn't like the effect on the sound produced by the felt but I have stuck with the foam around the horn mouth. Robert

Finally here is my crossover design for the RF3. I think I will start a new topic sometime and explain more about what I have done to arrive at this circuit. But for now here it is for anyone who wants to try it. The effect of the notch filter on the woofer is easily heard if you disconnect the tweeter and play music through the woofers only with and without the notch filter. The tweeter crossover was altered to account for the removal of the treble output of the woofers by the notch filter. I have not settled on the amount of attenuation of the tweeter. At the moment I think 6dB is about right. Robert Edit: The schematic had the polarity of the tweeter incorrectly marked. See later post for revised version

Hi Guys I haven't forgotten you. I'm back home and will post the xover in a couple of hours time . A few things to check- I want to make sure I post the correct version Robert

I have just noticed that the US Klipsch web site no longer lists the detailed specs of discontinued models. There is just a brief description and pictures and then a link to the current models. If anyone is looking for specs, the Australian Klipsch web site currently has the more detailed specs available. Just type the model in the search box on the home page Robert

Yes it is open cell foam.The Peavey horn looks like the horn is molded so the foam sits flush with the inside surface and wraps around the mouth edge. I tried felt inside the RF3 horn because i figured thick foam inside would change the horn dimension but to me it didn't sound right. A foam strip around the mouth did improve the sound. Robert

I tried inside the horn (see photo of a Peavey horn) but I didn't like what it did to the sound. I ended up with a strip around the edge of the horn on the outside sounding the best to me - but the effect was not dramatic. Robert

One mod you might like to try is placing some foam around the mouth of the horn just on its outer edge. I ended up using 10mm open cell sealing strip. The foam seems to level out the response above 5kHz. I found the effect on the level is measurable. In my opinion the effect on the sound is not massive but it does make it a little clearer and more focused. There is an interesting article about this by Jeff Poth called Foaming at the mouth You might want to try some foam on your horns (its cheap) and see if you can hear a difference. Robert

Sorry I cant help you with the RC-3 and RS-3 crossovers. I bought my speakers with an RC-3 center but I sold it because I only listen to 2 channel music. I'm not into home theater so the changes I made have been for music not movies. Robert

I have never heard a pair of RF7's but I would guess they are better speakers. I paid around $400 for my RF3's about ten years ago. At the moment in Australia I could buy a new pair of RF7's for US$7400 (discounted!!) or a good second hand pair for around US$5000. I can upgrade my speakers with new parts for a fraction of that.