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Forte II K-53 distortion in quiet passages


Unity_coupled

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I was having an issue with distortion (more like a "fuzz") from the mid horns that was audible during quiet music/low harmonic content (especially Chopin nocturnes) in both of my fortes and thought it was possible they had been over exerted at one time, so I ordered a replacement set of diaphragms from Bob Crites.  I went along with the guide and installation seemed to go fine, but the distortion still persists in both mids.  The pole piece didn't appear off-center and I was very careful to not let the coil contact the magnet assembly.  Has anybody else encountered this problem?  Is there any chance the titanium diaphragms would fix this?

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send your networks to Bob Crites he will install all new capacitors and he will find and correct your problem. In my opinion the Klipsch Ti mid diaphragm is the best that there is for this driver you can purchase them from Simply Speakers and Bob can install the Klipsch filter section that they use with them or you can run them with out it and see what you think. I have installed a good number of ti mid diaphragms and never used the filter and would not. Just so you know I have two sets of Heresy3 with the ti diaphragms and the filter section mentioned so I do know what they sound like. Your call on the filters but if you do want them Bob is your man. Best regards Moray James.

Edited by moray james
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What device are you using to play music, are you streaming?  I have also heard Chopin pieces distorting at times at low volume but only while streaming content off of Pandora and the like and found that quite odd.    While other piano music even when played quite loudly, never does.  It could be the recording itself,  the poor quality of streaming or some other issue that has nothing to do with the quality of your speakers.  One test you can preform is to listen to the recording on headphones and see if you still hear the distortion.  If you hear it through the phones too, you will know it is not the speakers.

Edited by shiva
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The source media for the Chopin was a 24 bit 88.2khz FLAC, PCM into my Anthem AV receiver.  Other sources and music have it too.  The distortion is not present through headphones or other speakers that I connect. 

 

I pulled the diaphragms and measured around the gaps with my calipers.  I might've spoken too soon...One pole piece is off center by about .007" and the other by about .005.  Could that be the source of my problem?  I'm tempted to get the titanium drivers (with the magnets) if they're still available.

Edited by invalidbuffalo
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If you are going to replace diaphragms buy them from Bob & not Simply Speakers.

Bob has a phenolic diaphragm mid which I like better than the stock Klipsch phenolic mid but not near as much as the ti mid which as far as I know is only available from Simply Speakers. Bob does have a ti tweeter diaphragm and I have to say that I like it better than the stock Klipsch ti tweeter diaphragm. If I am in error about this and Bob does now have a ti mid diaphragm I apologize for any error, please let me know if this is the case.

Edited by moray james
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Sorry, but late to the party here :)

 

I am curious as to how long you have had your Forte'IIs?

 

Is this a new purchase, and did it show up just as soon as you hooked up the speakers or?

 

How are you amplifying those head phones?

 

I am also curious as to if these are new speakers to your system, what were you running before?

 

I only ask all of this as these speakers are definitely capable of picking up low level distortion coming from an amplifier. Although this usually presents more as a hiss coming from the tweeters than from your mids.

 

If this is a new purchase for you, I would also then recommend having the cross overs gone through as well.

 

Good Luck! :)

 

Roger

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See my responses below...

 

Sorry, but late to the party here :)

 

I am curious as to how long you have had your Forte'IIs?

 

>>Three months

 

Is this a new purchase, and did it show up just as soon as you hooked up the speakers or?

 

>>I didn't notice it at first but I started detecting it as familiarized myself with the speakers and listened to more music through them...I still don't hear it 80% of the time...you hear it the most with solo piano.

 

How are you amplifying those head phones?

 

>>I plug into the receiver's headphone jack which connects to the amplifier output through a voltage divider

 

I am also curious as to if these are new speakers to your system, what were you running before?

 

>>Was running VOTT A7's before...no distortion

 

I only ask all of this as these speakers are definitely capable of picking up low level distortion coming from an amplifier. Although this usually presents more as a hiss coming from the tweeters than from your mids.

 

>>I've taken the troubleshooting steps and concluded the distortion is definitely coming from the mid driver

 

If this is a new purchase for you, I would also then recommend having the cross overs gone through as well.

 

>>The speakers have Bob Crites' full Forte II crossovers so I doubt it's that, but I don't have another 16 ohm mid driver handy to test.

 

Good Luck! :)

 

Roger

 

Can anyone comment on the pole piece centering, and whether or not it's within tolerance?

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If you are going to replace diaphragms buy them from Bob & not Simply Speakers.

Bob has a phenolic diaphragm mid which I like better than the stock Klipsch phenolic mid but not near as much as the ti mid which as far as I know is only available from Simply Speakers. Bob does have a ti tweeter diaphragm and I have to say that I like it better than the stock Klipsch ti tweeter diaphragm. If I am in error about this and Bob does now have a ti mid diaphragm I apologize for any error, please let me know if this is the case.

 

 

I would not trust any new diaphragms from Simply Speakers in my gear.

 

Aftermarket recone kit or surrounds maybe but diaphragms a no in my book.

 

I normally prefer Phenolic diaphragms myself anyways but to each their own.

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Does klipsch still have the titanium drivers or diaphragms available directly?  How would I go about ordering a set?  I've heard it's not as easy as just calling them up...

 

I'm seeing reports from others that the diaphragm from Simply speakers is an authentic part...but I hesitate to spend more money since I just bought ones from Bob, and I'm not convinced the diaphragms are the issue. 

 

Is there anything preventing me from nudging the structure so the gap is more uniform besides magnetism (is the magnet structure glued together)?

Edited by invalidbuffalo
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If you are going to replace diaphragms buy them from Bob & not Simply Speakers.

Bob has a phenolic diaphragm mid which I like better than the stock Klipsch phenolic mid but not near as much as the ti mid which as far as I know is only available from Simply Speakers. Bob does have a ti tweeter diaphragm and I have to say that I like it better than the stock Klipsch ti tweeter diaphragm. If I am in error about this and Bob does now have a ti mid diaphragm I apologize for any error, please let me know if this is the case.

 

I would not trust any new diaphragms from Simply Speakers in my gear.

 

Aftermarket recone kit or surrounds maybe but diaphragms a no in my book.

 

I normally prefer Phenolic diaphragms myself anyways but to each their own.

Jason: the ti mid diaphragms from Simply Speakers are NOT after market products they are genuine Klipsch Factory parts available through Simply Speakers they are the only ti mid available for this driver in all of its numbered confusing name version. I don't want any mistakes about this to cause unnecessary confusion. I am sure that you would agree.

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After a night of adjusting settings, a couple of gear swaps and much more listening, I've determined the source of the distortion to be the room correction dsp of my MRX 310.  Reducing the max correction frequency in the ARC software to 300hz seems to mitigate it.  I probably didn't hear it in my other speakers because the fortes are the most revealing.

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  • 11 months later...

I'm back with an update:  Just to preface, both fortes currently have Bob's phelonic mid diaphragms, Ti tweeter diaphragms, and his full forte II crossovers.

 

With the acquisition of a UMIK-1 and REW I'm finally able to shed more light on the problem with some objective measurements.  For testing I played a 1khz sine wave on my computer through the optical port with 24/192 sample rate.  The spectrum below was captured at the front right amplifier output of my AVR through a voltage divider connected to my audio interface.  The signal as decoded and amplified by the receiver is effectively free of harmonic distortion.

direct out.jpg

 

And here's the same signal recorded from the right-side Forte with the UMIK placed on-axis 2 inches away from the mouth of the mid horn.  Harmonics!

speaker.jpg

 

Similar thing in the left speaker:

leftspkr.jpg

Is that amount of harmonic distortion in the K-53 normal?  Would a titanium diaphragm have less?

 

 

To verify the mic itself wasn't introducing distortion I pointed it at one of my studio monitors...  Not a perfect test but I'm willing to bet the mic (brand new) reads accurately.

monitors.jpg

 

 

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