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Discussion Starter · #1 ·
I am trying to run a pair of 4ohm speakers in a 6-16ohm rated system. I know impedence mismatch can be an issue, but I don't know if that is what the problem is here.

The speakers play fine, but on a random basis the left speaker cuts out and the volume drops really low on the left speaker only. The right side continues to play at normal volume.

Here's what I've done to diagnose the problem:

1. Replaced the speaker with the exact same model.

Result? Sound still cuts out intermittently.

2. Replaced speaker wire and checked connections.

Result? Sound still cuts out intermittently.

3. Replaced receiver with another 8ohm-rated model (unfortunately I don't have a 4ohm amp to try)

Result? Sound still cuts out intermittently.

So, at this point, having swapped out both the speaker and recevier, I can only think of two explanations for the sound randomly cutting out:

1. The impedence mismatch-- the speakers play fine at times, but when impedence of the signal becomes too extreme, the speaker cuts out and the volume drops. However, from what I've read online about amplifier protection circuits, I thought that the receiver would just shut down if if overtaxed. Not continue to play at a reduced volume on one channel.

or

2. I have two speakers with faulty crossovers or tweeters.

Does the symptom of intermittent volume drops seem consistent with the impedence mismatch? Before I shell out the money for a 4ohm-stable amp or receiver, I need to be sure the impedence thing is the problem. Any advice would be most helpful!


Thanks.
 

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If you replaced the speaker and it's still a problem, IMO you need an amp or receiver rated for a 4 ohm load. Or replace the speakers with 6-8 ohm speakers.
 

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A power amp of sufficient power will solve the problem if the problem is power. If it is something else you still will have the problem.

For grins, as a troubleshooting exercise switch (at the back of the receiver) the left and right speakers. if the problem is in the receiver, the right speaker should go out. If it continues to be the left speaker, I would suspect a wiring problem.

Frankly, I cannot think of a reason a nondefective receiver would always have problems in the left, and never the right, unless something else is wrong. Like an intermittent short. But I surely don't know it all.
 

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I am trying to run a pair of 4ohm speakers in a 6-16ohm rated system. I know impedence mismatch can be an issue, but I don't know if that is what the problem is here.

The speakers play fine, but on a random basis the left speaker cuts out and the volume drops really low on the left speaker only. The right side continues to play at normal volume.

Here's what I've done to diagnose the problem:

1. Replaced the speaker with the exact same model.

Result? Sound still cuts out intermittently.

2. Replaced speaker wire and checked connections.

Result? Sound still cuts out intermittently.

3. Replaced receiver with another 8ohm-rated model (unfortunately I don't have a 4ohm amp to try)

Result? Sound still cuts out intermittently.

So, at this point, having swapped out both the speaker and recevier, I can only think of two explanations for the sound randomly cutting out:

1. The impedence mismatch-- the speakers play fine at times, but when impedence of the signal becomes too extreme, the speaker cuts out and the volume drops. However, from what I've read online about amplifier protection circuits, I thought that the receiver would just shut down if if overtaxed. Not continue to play at a reduced volume on one channel.

or

2. I have two speakers with faulty crossovers or tweeters.

Does the symptom of intermittent volume drops seem consistent with the impedence mismatch? Before I shell out the money for a 4ohm-stable amp or receiver, I need to be sure the impedence thing is the problem. Any advice would be most helpful!


Thanks.
It sure would be good to know what your equipment is and how hard you're driving it. That would really, really help if you want anyone to guess the reason for the problem.

If you're driving it hard, that's the cause, along with the fact that your amp wasn't designed to see a 4 Ohm speaker. Also, the speakers may dip below 3 Ohms which makes the amp work harder, may overheat and that might activate the protection circuit but again, we can't know this.

How many speakers do you have? If you have four of the same, wire them in series and try it- if it still cuts out, the amp has a problem.

Do you see the lights flicker or dim on loud passages? That might indicate an electrical problem.
 

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Discussion Starter · #7 ·
Thanks for the input everyone. Since some of you asked about the hardware, I am using an Onkyo NR-525 AVR with BG Radia PD-6LCRi in-wall speakers. The speakers have been custom-fitted into columns that flank my projector screen, so replacing them with a different brand is not possible. I have three of the BG Radias, one for the right, center and left fronts. All my testing so far has been done in stereo (not surround mode) with the bass going to an attached, powered sub (Rythmik Audio LV12). I have not hooked up the center channel speaker yet.

What I find bizzare is that I hooked two different receivers up to the speakers, an experienced the same issue. Hooked up a different CD player, different speaker wires, and still i get the drop outs. Tried replacing the left speaker with the "virgin" center channel one, and still got the sound dropouts.
 

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Those speakers are rated at 4ohm. The 525 isn't made to drive 4ohm speakers. You can try any combo you wish but until you get an AVR rated for 4ohm loads you will continue to experience problems. The reason why one channel drops more than the other is because it may well have some defect that causes it to shut down sooner than the other.
 

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While I agree that it's by far best to use amplification that is specified to handle a four ohm load, if (and we just don't know) the OP uses say 10 watts max per channel for peaks (not impossible at all for folks who listen at 15 or 20 dB below reference) then the amps' "inadequacy" will never become relevant. Not enough power to really challenge the amps even at four ohms. And if (as may well be possible) the left channel amp is defective, that's not a power problem, it's a defective amp problem. It can happen with any equipment. I remember in my higher end fascination days wandering into one of the local stores (Arcam, Musical Fidelity, other Brit brands as well as US-made equipment) and listening to a stereo receiver I had a particular interest in. Had significant distortion kind of laying underneath the main sound. LIke a really bad 70's transistor guitar amp. Honestly, the salesperson did not hear it until I pointed it out to him. A few days later he confirmed it was a bad amp module, and was getting fixed. Point being, even relatively expensive equipment can be faulty "out of the box" and luckily for consumers most significant problems show themselves quite quickly, so we can return or at least take advantage of even the stingiest warranties to get it right.

If the receiver is defective, and the defect is causing the problem, suggesting it is a power problem is, ummmmm, silly. Get the device replaced or fixed if you can. Switching the speakers will help identify whether that's the problem. Maybe there's a couple of strands of speaker wire inside that wall at the speaker connection or at the back of the receiver that are flying loose and creating a little short circuit, resulting in shutdown when power requirements get high enough. That's not a power problem, it's a minor wiring error and fixing the wiring error is (a) cheaper and (b) more likely to actually fix the problem than any hardware acquisition.
 

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you could try further testing using your "spare speaker". Hook it up in series with the speaker in question and see what happens. BUT you didn't answer the question about what power / sound levels are you playing at. If you are pushing things then the rcvr maybe be "responding" poorly to the low impedance and power push. You didn't mention what the other rcvr was that you tried with the same results.
 

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Puzzling!

When dealing with intermittent issues it can be frustrating.

Since you indicate you have already swapped out the entire system one piece at a time and the problem persists, I recommend an exorcist.

Probably you got confused somewhere in your experimentation. Either that or you are using two identical receivers with the same program material played too loud for the amp to handle and it is cutting out on the left channel because it has signal content that interacts with the amp/speaker combo.

Nah, you just got confused.:)

I recommend a good night's sleep after the exorcism and try again when you are refreshed. You will isolate it eventually.
 

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You don't mention what volume level you're using. The AVR shouldn't have any problems at moderate TV listening levels, but anything higher (eg. movie listening levels) would cause the AVR to have issues which in that case, upgrading to a model with main zone pre-outs and purchasing a 200W+ external amp or an AVR which is 4-ohm stable is your best bet. :)
 
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