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One speaker louder than the other


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I have a pair of Cornwalls for my side effects and a pair for rear effects in my 7.1 HT. While setting the volume levels both automatically via my processor and manually using a sound meter, one of the cornwalls is louder than the rest. I have run several tests and found the following. The problem is with one specific speaker regardless of room positioning. All three drivers work fine. All three drivers are identical to the ones in the opposite speaker. Amps are the same etc.

Could this be a problem with the crossover? The differance is minimal, and not noticeable audibly. But, on the meter and on the processor microphone, they resgister -3 dB for one (identical to the two rear effects) and -6 dB for the problem child. These settings on my system will yield "reference" settings for the HT.

Any ideas would be appreciated.

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Is it an old style with the screw type terminal block. If so, check with an ohm meter. If more that 4 ohms DC the ring terminal on the inside back of the cabinet needs replacing. Otherwise I would suspect the 4uF midrange cap.

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Is it an old style with the screw type terminal block. If so, check with an ohm meter. If more that 4 ohms DC the ring terminal on the inside back of the cabinet needs replacing. Otherwise I would suspect the 4uF midrange cap.

Yes, it is the old style terminal block. I will check the terminal.

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It may be of aid in troubleshooting to note the following.

The test tones used in HT are usually limited in bandwidth and usually to the midrange. There may be a warble tone or band limited noise.

This means that perhaps only the midrange horn is being fed with the test signal and therefore the issue might restricted to the midrange.

It is impossible to say for sure because if you have an amp or wiring issue upstream of the speaker unit, it is going to affect all the drivers, including the midrange.

Gil

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Gil:

The problem is with the speaker itself. As a test I have moved it around the room and connected it as rear effects and the other side of the side effects. The problem follows the speaker eventhough it is using a different amp and wiring every time.

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I wrote about wiring and the amp somewhat for the sake of completeness and for the consideration of future generations. Smile.

The problem could arise from the components of the crossover or the driver itself. I'm still thinking the test signal is in the range of the midrange driver but we await your findings on that.

Do you have the ability to test at individual freqs?

Also, is it possible that someone has altered the internals of the speakers? Did you buy them used, are they new to you? etc. Do they both use the same drivers and crossovers? What are the serial numbers? You will probably have to open them up to determine answers to many of these questions.

Tell us all more.

Gil

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Gil:

I purchased them used about a year ago and had not set them up until recently. I first found that they had two different tweeters, which were both dead. I swapped them out for Bob's CT-125's in order to match my front and center CT-125's.

It was during the final calibration that I got those odd readings for that pair. The other pair of Cornwalls are identical. I will have to open them up again and take note of the internal components more carefully.

Right now I need to get an ohm meter that can measure around the 6 ohm range. I only have a 1Kohm multimeter.

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Again I'm guessing on the midrange. It could be that a previous owner put in a different driver.

I'd check the wiring for tightness and also polarity of connection. If something is out of phase (wiring to woofer or to the mid) you could get a different output.

Best,

Gil

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Well, here are the results of some testing. The serials on these are 17S223 and 17S224.

Both show 4.3 ohms at the exterior terminal as well as the input terminal on the crossover itself. Both mid range drivers show 10.5 ohms. Both woofers show 4.0 ohms. Tweets are the same since I just installed a new set of CT-125's.

The crossovers are visually identical, Klipsch original Type B. I checked the connections and will try measurements again.

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have you tried swapping out crossovers between the suspect one and one of the good ones to confirm the bad xover theory....

a note...if it is a bad xover componet .....when repaired...possibility exists that the fixed speaker will sond different due to have newer xover parts than the others....cycle will only end when the changes to one are done to all.

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