Klipschguy

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I have a tone generator app on my iPhone that will produce audio spectrum frequencies; it is useful for identifying room resonances, bad speakers drivers, et cetera. I use a free app called Sonic. A word of caution: Be careful with cranking the individual frequencies of the audio spectrum as it can damage your system. Ex: cranking 20,000Hz trying to hear it can fry your tweeter (“It was only 146dB, but I can hear it!!), or cranking 20Hz trying crack the foundation of your house can damage the woofer. Moderate levels and common sense are recommend.

From your description, there is a good chance you have a bad diaphragm either in the tweeter (K77) or the midrange driver (K55V). Play the distorted passage with your ear beside the midrange and alternately, the tweeter to determine the offending driver. (Piano music is usually good for revealing a bad midrange horn diaphragm.) The original drivers can be repaired.

Thanks, Jim. Those attenuators look like they would work well.

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Peter speaks the truth.

Yes. My apologies for not being more clear. (Funny, the “Old School” in me tends to assume everyone is running their Heritage with a more traditional 2 channel preamp/amp combination.)

Thank you, Babadono! That is exactly what I need.

Yes. The sub will crank right up without the mains. There just does not seem to be enough voltage to drive the sub because the KHorns are so sensitive/efficient. What is the best way to add gain to the sub?

I would recommend taking the other screw to a local hardware store, confirm the thread (you can try various hex nuts until you find the one that fits), measure the length of the threads to get your machine screw length, and then buy the screw from that store if they have it, or look online to find the exact screw you need.

Well my subwoofer’s plate amplifier has an internal crossover (actually, a pretty good one), so there is really no need to tap into the woofer leg of the Khorn’s network because the sub only allows the low frequencies to pass to the driver any way. Also, a Khorn’s woofer leg crosses over at 400Hz (around the middle of the piano), so the frequency range would not be appropriate for a subwoofer which should really operate at frequencies about 80Hz and below. However, you do give me an idea for a potential solution: I could make a resistor box that brings down the amplifier’s speaker output to any potential “line level” desired. Thank you for your thoughtful replies. Respectfully, Andy

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Ok. Thank you for the replies. I can probably adjust the input sensitivity/gain by soldering in some different resistors. Now to find a wiring diagram…

The sub is running off a level input from the preamp, 2 channel setup. The volume is maxed on the sub, hence the need for more gain.

I have an M&K sub with a Khorn setup. The Khorns are so sensitive, the sub does not have enough gain to properly match the line level for an appropriate mains-to-sub balance. There are some subs with adjustable input sensitivity; this sub is not one of them. Any recommendation or experience with changing the input sensitivity (besides “Buy a new sub.”? Maybe solder in some different resistors so volume control will have enough gain?