PSS, your speakers are fine. Subbing a diff amp is the right next step.

I hope so......what do think about the earlier post about a possible issue with a bad HDMI on cable box? I'm trying to see if the homeowner was watching cable each time it went into protection......

Denons don't like 4 ohms. Your speakers are 6, which means they will dorp down below 4 ohms depending upon the frequencies...

Go with a ballsier amp - Yamaha's are pretty stable.

Mr. Stanley:

Grrrrr. Haven't you been reading, or just don't believe it?

The "nominal" impedance of a loudspeaker is the lowest point of impedance in the audio spectrum above the woofer resonance, rounded off to 4, 6, 8, 16, and a few other really rare values, unless the crossover is made in a way that dumps signal to ground through an inductor or capacitor and thus brings the impedance lower. Such a speaker would be some tweaky supposedly high-performance thing, like a tower where the woofer only goes up to about a hundred Hertz, or some other thing where the "designer" designed instead of engineered due to lack of knowledge.

The word "nominal" is related to the words "name" and "noun." All it means "this is what we call it." Check ANY PLACE you see the word "nominal" and you'll see it does not define an exact value but rather an approximate or expected value.

This "shorting to ground" thing is not an issue once you're above about 200 Hz anyway because the amount of power going out of the amp from there on up is NOT going to put it into protection, unless you're trying to kill the audience with SPL.

That said, I think many of you know my opinion of Denon (Matt was ready to "beat me up in the parking lot" about it at one time). Get Yamaha.

EDIT BEFORE POSTING: I WAS WRONG.

What I described above is what we did at Marantz when there was Loudspeaker Engineering, with deserved capital letters, around 1980. (I was just the assistant and learning every day, NOT the Engineer.) The truth is much worse. For instance here's the impedance curve of a supposed 8 ohm speaker. Go to the source page and read it for some enlightenment, such as I just got. It's at [Link: churchsoundcheck.com].



The next one, from another site, is a REAL GOOD education about impedance versus frequency, but being educational in nature it goes along exactly with what I described above from my days at Marantz.

Notice that DC resistance is the measurement at the far left, at Zero Hz, because DC is Zero Hertz.* That section of the curve labeled "impedance changes here due to motion of diaphragm" can be modified to have a less pronounced peak; a port does that and the various physical factors involved affect just what the changes are. Basically, the port introduces a smaller peak at a lower frequency and reduces the woofer's main resonance impedance.

Note also that this educational graph behaves exactly as I described things up above, but the first curve I showed is a real world example of impedance Hell.

Whatever:




*I make the point that DC is Zero Hz to try to pound into people who use a DC Ohmmeter to measure impedance that they CANNOT measure impedance with DC, only resistance.

Why did PSS go back to the thread title, add "STILL HAVING AN ISSUE," then put two question marks on it like we should know if he's having an issue? Doesn't he know?  Or maybe that's the proof that he's having an issue!

You tested it out for hours. It worked fine for you. The customer called on a Saturday night.
My guess: The customer is abusive with the volume - he's turning volume up to max and leaving it there. I run into these people every now & then; sound can be like nails on a chalkboard at x10 (make your ears bleed) and they will be just sitting there listening to it like nothing is wrong. Might even comment it sounds good to them. Some people have severe mental issues.
Do you use the 'max volume' feature in the AVRs? Every installer/dealer should but you didn't mention it yet - although someone earlier did already ask this.

The HDMI thing is interesting. Swapping to the Pioneer might fix it or swapping the cable box.

The load the speakers are putting on the Denon could also be the problem. Again, swapping to the Pioneer might fix it.

Could be the Denon was just a POS. And putting in the Pioneer will fix it.

Without an impedance meter, you can't fully checkout the speakers (xover and all). But your ohm meter is a good place to start. You tested the speaker leads but you didn't say: Did you test from earth ground to each of the speaker leads. Very important, could show a pinch/shorted wire in the walls somewhere.
 

I thought someone mentioned that, but yeah, EACH of the speaker leads should be tested to earth ground when disconnected from the amp and from the speakers. Resistance should be infinite.

Want to measure the impedance? Get a 1k ohm resistor. Get an audio generator, preferably one you can sweep. Get an amp that will output 10 volts DEAD FLAT across the audio spectrum (that would be 12.5 watts if fed to 8 ohms). Connect the resistor to the hot of the amp output. Connect the speaker from the other end of the resistor to ground. Now...

10 volts out of the amp provides a voltage drop of 10 x 1/1000 = 0.010 V or ten millivolts for each ohm of the resistor. An 8 ohm speaker in series with the resistor raises that resistance (by less than 1%) so the formula becomes 10 x 1/1008, and almost exactly .08 volts will be across the speaker. 8 ohms gives you real close to 80 millivolts. So at this point you need an AC meter that responds flat across the audio spectrum and can measure down to, say, 1 millivolt. Not difficult but expensive. A scope can be used if you know how to read RMS from a sine wave.

Sweep the audio oscillator and look at the voltage across the speaker. As the speaker's impedance rises, the accuracy will diminish, but it will always easily be within about 5% for the speakers we use.

did not see this throughout the thread..........take a nine volt battery and touch the speaker lead, if it pops the speaker....speaker good, if it sparks at the battery, speaker bad...................simple caca..........

oldest trick in the book.......

just saying.....

RR

There are so many things wrong with what you just replied.

1) The battery will always spark. Depending on the contact area when you first apply the wire, freshness on the battery, and speaker's DC resistance; it could be a big spark or little one. Has nothing to do if a speaker is bad or not.

2) Just because the speaker pops, does not mean it's good. It just means it can make noise. Speaker could easily still be f'd!
Plus, depending on the speaker and xover. You may not get a pop at all, you just charged a capacitor. Shorting the wires together might give a pop (might). Again depending on the circuit.

The only things the 9volt battery thing is good for:
Tells you real quick & dirty if there is a speaker connected to the other end of the wire. Also might tell you if a high pass xover is inline (the popping or not of 9 volt and shorting the wires after).
And can tell you absolute polarity by seeing if the cone move in or out (in: you have + on - terminal. Out: you have + on + terminal).

in your opinion......
works for me

None of what I said was an opinion, it is based on fact.
 

And you just indicated the way to find out if a speaker has a capacitor in series, to block the lowest frequencies- if you get no pop or an extremely weak pop when the battery is connected to the speaker wires, it could be open, or it could have a cap. Make sure the area is extremely quiet and touch the wires together- if you hear a faint click, the cap has discharged and this is repeatable- connect the battery, connect the leads- it will produce a faint click in both cases.

However, it's not necessary to use a 9V battery- a AAA works just as well and a battery holder with test leads is very easy to find.

I don't remember seeing it, but if the speaker wiring was hidden, I would reference each speaker wire to the rest. The DC resistance of each speaker should have been measured before starting.

Connect one lead from the meter to the Left + wire and touch the other probe to each speaker's positive wire. If you see ANY connectivity, you have a problem- if it shows close to zero Ohms, it's shorted to that wire and if it shows the load from a speaker, the negative wire is in contact.

Repeat, with the meter's lead connected to each of the other + leads, after each of the others has been tested.

If nothing is found, measure from each + to the closest electrical ground. Since many receivers and other AV equipment has no ground pin, using the case isn't the best choice. Connect to the flange of a receptacle, instead.

We all see complaints about drywall installers screwing through our wires, but I don't see much mentioned about thorough testing for this problem when an amp shows a problem.

Sure, a battery is a quick and easy way to test for continuity and speaker operation, but it doesn't indicate anything WRT how well it will work. It would still pop if the speaker was at 1 Ohm. The difference is that the spark would be larger and the pop would be quieter.

Rhea's test is a very good one and it is very informative. Brad's comments are accurate, but that just means that Rhea's test is not all-inclusive; it does not mean Rhea's tests are not informative. Basically, the less you know about what you're doing, the more complicated the testing needs to be. Rhea's tests work for him in separating dead speakers and dead shorted speakers from the rest of the universe. That's A LOT of information considering how simple his procedure is!


That's what I said. Now, skipping a paragraph,


This test falls short here, because it does not specify measuring the resistance of the - wires to ground.

That might seem ridiculous because it's only the hot that can get you in trouble if it's connected to ground or shorted to something else, right? NO. The - wire can get you in trouble if it's shorted to an electrical ground that has some current running past it and, as a result, has a voltage above zero. Any such voltage indicates a ground loop, and that voltage might be being fed into the chassis of the amp via the power amp ground, which could cause distortion, noise, or smoke.

When you're troubleshooting, measure everything to everything! As in the case of Brad's addenda above, not every one of these measurements will tell you anything. But don't stop halfway. I was working with a beginner the other day; all four speakers of a system seemed to be working; we IDed their locations and labeled wires, using, yes, an AA battery; once we had located three he thought we were done. Again, no. I put the battery on the fourth wire pair and verified that it worked at that level.

Don't assume that, if you can test four things, finding three testing good means the fourth will test good.


Rhea's test divides the universe between those speakers that give zero results and those that give some results, which is A LOT of information if you have no information. It's still a good test, but if he's not listening to how loud the POP is, he'll become misinformed.

This entire thread is filled with quick answers, and all of us, once we think about it, know there's more to it than any one of these answers. I don't think any of these responses deserve any criticism at all, particularly in a world where the entire list of things to do will be criticized as a post that's "too long."

It doesn't fall short because it's not necessary to specify measuring from negative to ground- if any continuity is seen between + and ground, a problem exists and the speaker load would be seen on the meter. This assumes the speaker wires were disconnected from the amplifier, as they MUST be, in order for the tests to be valid.

When you're troubleshooting, measure everything to everything! As in the case of Brad's addenda above, not every one of these measurements will tell you anything. But don't stop halfway. I was working with a beginner the other day; all four speakers of a system seemed to be working; we IDed their locations and labeled wires, using, yes, an AA battery; once we had located three he thought we were done. Again, no. I put the battery on the fourth wire pair and verified that it worked at that level.

Don't assume that, if you can test four things, finding three testing good means the fourth will test good.

Rhea's test divides the universe between those speakers that give zero results and those that give some results, which is A LOT of information if you have no information. It's still a good test, but if he's not listening to how loud the POP is, he'll become misinformed.

"That might seem ridiculous because it's only the hot that can get you in trouble if it's connected to ground or shorted to something else, right?  NO.  The - wire can get you in trouble if it's shorted to an electrical ground that has some current running past it and, as a result, has a voltage above zero.  Any such voltage indicates a ground loop, and that voltage might be being fed into the chassis of the amp via  the power amp ground, which could cause distortion, noise, or smoke."

Absolutely- ANY connection to ground, or any other wire that wasn't intended, can and will cause problems.

This entire thread is filled with quick answers, and all of us, once we think about it, know there's more to it than any one of these answers. I don't think any of these responses deserve any criticism at all, particularly in a world where the entire list of things to do will be criticized as a post that's "too long."

There are lots of ways to test for this, but whatever method is used, it must be definitive.

Last year, I posted about a Denon receiver that had blown amplifier channels, which prompted a service call. When I pulled the receiver out of the cabinet, most of the HDMI cables, all of the digital audio cables and one of the antenna wires had been disconnected, as well as a couple of their Bose Acoustimass Sat/Sub speaker wires. One of the speaker cables had been disconnected at the speaker and the wires were touching. She asked if I would be charging for the work and sending it in for service. Damn right! If someone goes in and yanks most of the cables out in their attempt to connect an AppleTV, I'm not going to eat that! I should have told them that the AVR has an HDMI port on the front, but when I asked if she wanted me to connect it, she said they could do it. This was months before the service call, but I guess being cheap trumped doing it right.

The DC resistance measured was in the 5 Ohm range. I had installed a pair of in-ceiling speakers to replace the old ones, so the fronts were where the problem may have existed, if the shorted speaker wires hadn't caused the actual problem. How four channels would blow because of that, I don't know but I suspect someone tried to connect speakers in all kinds of configurations with the unit powered up. When I connected a known good speaker to all channels, most didn't produce sound.

Anyway, when I got the call from the service center, the tech said that most AVRs use very similar amplifier circuits and devices, adding that none of them really like 4 Ohm loads, but some will tolerate this better than others. She repeated the comments about using 8 Ohm speakers and included a sheet that included this.

This is the only Denon I have shipped for an amplifier problem and I have rarely seen an amplifier that blew when A) the speaker wires were in good condition, B) the speakers didn't have some kind of problem and/or C), the user didn't crank it to WOT. THAT's the reason I limit the volume control on ALL receiver installations when that's an option. Having checked literally thousands of receiver/integrated amp/power amp/speaker service pieces, it's no stretch of the imagination to think that it has been abused. OTOH, we saw a lot of these pieces come in with no apparent problem and it turned out that the speaker wires had been crushed by furniture, chewed by an animal, had a screw, or too much insulation had been stripped off and wire strands were causing a short.

LOOK AT EVERYTHING!!!!!!!!

FWIW, I built my speakers and the phase curve isn't particularly smooth and it's definitely not flat. The Denon receivers I have used with these have never shown any kind of problem and I do crank it, at times. Never shuts down, never blew a channel. OTOH, I can see my speaker cables but before I moved my equipment, the ones I used were buried but before connecting anything to the speaker terminals, I made sure I had no shorts. Denon isn't crap, nor is most of the stuff out there. It might be a heat problem from being enclosed, it could be from abuse.

We don't have enough information.