What could be wrong with my receiver, regarding phase ?

[rijnton]

Today I noticed a very strange problem with my receiver, although it may exist already a long time, maybe even since buying the receiver.
Because I sincerely hope that one of the experts here can give me some help or advice I registered here.
I am absolutely sure that the wiring from my B&W P4 speakers to my Yamaha RX-V757 is correct, because I double-checked and double-checked again, but the sound is out of phase. I can hear it with a phase test signal and with a mono radio signal as well. The latter is diffuse.
I reset the receiver to factory defaults and ran the setup again. I did not get a warning about being out of phase.
Still the mono sound is diffuse and the test signal reports being out of phase.
I did the test with the following configurations:
1) Test cd in stand-alone cd player to multichannel inputs receiver and to cd inputs. Both report out of phase.
2) Test cd in cd player of pc, connected to multichannel receiver: out of phase
Strange thing is however that when I play the test cd in my pc with digital connection to receiver, it is o.k. and not reporting out of phase.
Because when using the analog inputs the sound is wrong ,with the speakers correctly (at least theoratically) connected, I changed the connectors of 1 speaker. So on one of the speakers + on - and - on +. Everything sounds o.k. now including the test signal, except when using the digital connection. When I ran the setup I now get an out of phase warning.
To summarize: when speakers are correctly connected I get no out of phase warning but the sound is out of phase and when wrong connected, an out of phase warning but sound is fine.
It looks like something wrong inside the receiver but what could it be ?

 

[DD66000]

Any chance of trying another receiver? Is that receiver still under warranty?

It would seem that the analog inputs are wired reverse of the coax. So its either take the receiver in for a check, warranty or not, or just have to switch the speaker wires on the one speaker to match the input used.

Just another thought, did you check to make sure the reverse/normal stereo switch, if there is one, is in the normal position and not reverse stereo?

 

[Pyrrho]

Today I noticed a very strange problem with my receiver, although it may exist already a long time, maybe even since buying the receiver.
Because I sincerely hope that one of the experts here can give me some help or advice I registered here.
I am absolutely sure that the wiring from my B&W P4 speakers to my Yamaha RX-V757 is correct, because I double-checked and double-checked again, but the sound is out of phase. I can hear it with a phase test signal and with a mono radio signal as well. The latter is diffuse.
I reset the receiver to factory defaults and ran the setup again. I did not get a warning about being out of phase.
Still the mono sound is diffuse and the test signal reports being out of phase.
I did the test with the following configurations:
1) Test cd in stand-alone cd player to multichannel inputs receiver and to cd inputs. Both report out of phase.
2) Test cd in cd player of pc, connected to multichannel receiver: out of phase
Strange thing is however that when I play the test cd in my pc with digital connection to receiver, it is o.k. and not reporting out of phase.
Because when using the analog inputs the sound is wrong ,with the speakers correctly (at least theoratically) connected, I changed the connectors of 1 speaker. So on one of the speakers + on - and - on +. Everything sounds o.k. now including the test signal, except when using the digital connection. When I ran the setup I now get an out of phase warning.
To summarize: when speakers are correctly connected I get no out of phase warning but the sound is out of phase and when wrong connected, an out of phase warning but sound is fine.
It looks like something wrong inside the receiver but what could it be ?

Assuming that you are making no mistakes in your judgement about phase, it sounds like they got a couple of wires crossed in the preamp in the analog section, possibly going from one circuit board to another. Basically, you seem to be reporting a problem with phase with analog inputs, but not a problem when no analog input is used. So they probably accidentally hooked a pair of wires to each other's place. If it is still under warranty, I would try to get them to fix it. If it isn't under warranty, you don't need to fix it if you can use only digital inputs. If you are "handy" and it is no longer in warranty, you could take a peak inside to see if you can figure out which wires got crossed, but for most people, they should leave the cover on it and find a service center to fix it. I would talk to Yamaha, even if the warranty is expired, because if you are right, it would seem to be a manufacturing defect, and you might be able to persuade them to fix it for you for free anyway. If I am right about the problem, it would be a cheap and easy fix, once the mistake is located inside.

 

[TLS Guy]

Today I noticed a very strange problem with my receiver, although it may exist already a long time, maybe even since buying the receiver.
Because I sincerely hope that one of the experts here can give me some help or advice I registered here.
I am absolutely sure that the wiring from my B&W P4 speakers to my Yamaha RX-V757 is correct, because I double-checked and double-checked again, but the sound is out of phase. I can hear it with a phase test signal and with a mono radio signal as well. The latter is diffuse.
I reset the receiver to factory defaults and ran the setup again. I did not get a warning about being out of phase.
Still the mono sound is diffuse and the test signal reports being out of phase.
I did the test with the following configurations:
1) Test cd in stand-alone cd player to multichannel inputs receiver and to cd inputs. Both report out of phase.
2) Test cd in cd player of pc, connected to multichannel receiver: out of phase
Strange thing is however that when I play the test cd in my pc with digital connection to receiver, it is o.k. and not reporting out of phase.
Because when using the analog inputs the sound is wrong ,with the speakers correctly (at least theoratically) connected, I changed the connectors of 1 speaker. So on one of the speakers + on - and - on +. Everything sounds o.k. now including the test signal, except when using the digital connection. When I ran the setup I now get an out of phase warning.
To summarize: when speakers are correctly connected I get no out of phase warning but the sound is out of phase and when wrong connected, an out of phase warning but sound is fine.
It looks like something wrong inside the receiver but what could it be ?

That is a really strange fault! Do you have a volume control on your CD player, or any other player. If you do connect it to the pre ins on the receiver and see if it is out of phase or not.

The best way to really know what is happening is to use an oscilloscope. That will tell you the phasing between channels right away. Put a test tone through the analog circuits and see the phase at the speaker terminals and pre outs. Do this for analog and digital signals, and inject a signal to the pre ins for good measure. This will tell you what is going on right away.

This is a very strange fault and I have a hard visualizing how it could happen as receivers like that do not use balanced circuits. The signal the whole time is between live and the ground plane, and I can not see where there would be an opportunity to reverse phase in the preamp section. There might be in the output section, but that would not explain your observations.

See if you can have a tech perform what I have outlined.

Just to satisfy my curiosity, please check the phase of your speakers with a battery. Connect leads to each speaker input. Take the grills off the speakers. Now take a 1.5 volt battery. Connect the -ve terminal to -ve battery, and then touch the positive battery with the +ve speaker cable. Every time you touch the wire to +ve the woofer cone should move forward if the speaker is correctly phased.

 

[rijnton]

Thanks for the replies.
@DD66000: Unfortunately there is no warranty anymore. The receiver is already 3 years old. There is no reverse stereo swich on it.
@Pyrrho:I also checked with test signals found on the web. The in-phase is diffuse and not to localize, the out-of phase is exacly centered. That is when I have connected the speakers correctly + to + and - to -. I already took of the cover but the parts to take a look at are not easily accessible.
@TLS Guy: I have no volume control on my cd player and unfortunately I don't have an oscilloscope. I checked both speakers with a 1,5 V battery and the woofers move in the same direction so it is not the speaker's wiring.

Of course I could use the digital connections (and I did that actually until recently which is probably the reason that I didn't hear the problem earlier) but since I bought a rather good sound card (Xonar D2/PM), I want to use the analog to multichannel now, also for HD Audio.
Or I can leave it as it is now, that is with one speaker reversed. The phase testing is o.k. but I wonder if the sound quality is also optimized. I mean, supposed there IS an internal defect, would the sound quality improve when it was solved ?

 

[TLS Guy]

Thanks for the replies.
@DD66000: Unfortunately there is no warranty anymore. The receiver is already 3 years old. There is no reverse stereo swich on it.
@Pyrrho:I also checked with test signals found on the web. The in-phase is diffuse and not to localize, the out-of phase is exacly centered. That is when I have connected the speakers correctly + to + and - to -. I already took of the cover but the parts to take a look at are not easily accessible.
@TLS Guy: I have no volume control on my cd player and unfortunately I don't have an oscilloscope. I checked both speakers with a 1,5 V battery and the woofers move in the same direction so it is not the speaker's wiring.

Of course I could use the digital connections (and I did that actually until recently which is probably the reason that I didn't hear the problem earlier) but since I bought a rather good sound card (Xonar D2/PM), I want to use the analog to multichannel now, also for HD Audio.
Or I can leave it as it is now, that is with one speaker reversed. The phase testing is o.k. but I wonder if the sound quality is also optimized. I mean, supposed there IS an internal defect, would the sound quality improve when it was solved ?

Your last point is the real issue. It is most unlikely this fault is due to reversed wiring. More likely there is a component network causing phase shift. You can not assume that the phase angle between channels is 180 degrees. That is why seeing what is happening with a scope is so important.

I would see if you can find a local tech who can proceed along the lines I suggested, then you will know. Alternatively you could get a good older scope on eBay and check things out yourself.

The other option is to send that receiver to the recycling center. Without further tests I agree there is a huge level of uncertainty about what the situation actually is.

 

[rijnton]

Thanks again TLS Guy.
At first an update: I ran the Yamaha setup again and although it didn't solve anything (with reversed wiring on 1 speaker out of phase warning but phase test signal o.k.), I now don't have a difference between analog and digital connections. In other words: Having the speaker wiring theoretically wrong (on 1 speaker + to - and getting an out of phase warning from Yamaha setup), running a phase test signal it sounds o.k. (in-phase signal centered and out-of phase diffuse) on analog and digital as well.
Being not so technical I don't exactly understand your first paragraph. Do you mean that there is a reasonable chance that sound quality IS degraded ?
B.t.w., do you suggest with your last paragraph to dump the receiver and buy a new one ? I was already thinking of that and buy the new Yamaha RX-V863.

 

[Pyrrho]

Thanks again TLS Guy.
At first an update: I ran the Yamaha setup again and although it didn't solve anything (with reversed wiring on 1 speaker out of phase warning but phase test signal o.k.), I now don't have a difference between analog and digital connections. In other words: Having the speaker wiring theoretically wrong (on 1 speaker + to - and getting an out of phase warning from Yamaha setup), running a phase test signal it sounds o.k. (in-phase signal centered and out-of phase diffuse) on analog and digital as well.
Being not so technical I don't exactly understand your first paragraph. Do you mean that there is a reasonable chance that sound quality IS degraded ?
B.t.w., do you suggest with your last paragraph to dump the receiver and buy a new one ? I was already thinking of that and buy the new Yamaha RX-V863.

That does not make sense. If you reverse the polarity of one speaker, it should change the phase for all inputs. So if the analog and digital inputs were not in phase with each other before, they should still not be in phase with each other now. You might want to start over again, with a different phase test.

 

[TLS Guy]

Thanks again TLS Guy.
At first an update: I ran the Yamaha setup again and although it didn't solve anything (with reversed wiring on 1 speaker out of phase warning but phase test signal o.k.), I now don't have a difference between analog and digital connections. In other words: Having the speaker wiring theoretically wrong (on 1 speaker + to - and getting an out of phase warning from Yamaha setup), running a phase test signal it sounds o.k. (in-phase signal centered and out-of phase diffuse) on analog and digital as well.
Being not so technical I don't exactly understand your first paragraph. Do you mean that there is a reasonable chance that sound quality IS degraded ?
B.t.w., do you suggest with your last paragraph to dump the receiver and buy a new one ? I was already thinking of that and buy the new Yamaha RX-V863.

I think we may be getting somewhere now.

I have been on the B & W site, but can not find the order for the crossover.

However with many crossovers, especially common second order ones, and sometimes with others as well, the best frequency response in the crossover region is achieved with the tweeter polarity reversed. The crapo Yamaha auto set up system can not make sense of this common situation. If your speakers have reverse tweeter polarity, and many do, then you can NOT use the auto set up. You have to set everything manually and leave auto set up off always.

It seems to me this is by far and away the most likely reason for you your problem.

Turn off all auto set ups. Then play a good recording of a mono speaking voice and see which polarity to your speakers firmly centers the image and report back.

 

[rijnton]

Meanwhile I did a complete reset and a manual setup (level, distance etc.).
From the manual however I gathered that the auto setup doesn't make any changes with regards to phase. It only checks whether polarity is correct and gives a warning when not . The settings that are made (after confirming by pressing Select) are size, distance, equalizing and level.
I dont have a recording with mono voice, but used the signals found at:
eminent-tech.com
and for my standalone cd player a Dolby Surround test cd with in-phase and out-of-phase signals.
In both cases, and now analog and digital as well, the in-phase signals are only firmly centered when the connections on one speaker are reversed: + to - of receiver and - to + of receiver. So soundwise the phase is only correct when the wiring is not. It is also clearly to be heard when I switch the tuner to mono.

 

[TLS Guy]

Meanwhile I did a complete reset and a manual setup (level, distance etc.).
From the manual however I gathered that the auto setup doesn't make any changes with regards to phase. It only checks whether polarity is correct and gives a warning when not . The settings that are made (after confirming by pressing Select) are size, distance, equalizing and level.
I dont have a recording with mono voice, but used the signals found at:
eminent-tech.com
and for my standalone cd player a Dolby Surround test cd with in-phase and out-of-phase signals.
In both cases, and now analog and digital as well, the in-phase signals are only firmly centered when the connections on one speaker are reversed: + to - of receiver and - to + of receiver. So soundwise the phase is only correct when the wiring is not. It is also clearly to be heard when I switch the tuner to mono.

Then there is something wrong with that receiver. Only a scope can tell you the degree of shift. You can not assume it is 180 degrees, or constant with frequency. It should not cost much to have someone measure this. If the phase shift between channels is 180 degrees and constant with frequency, you can just reverse one speaker connection and forget about it.

If the phase shift is not 180 degrees, and not constant with frequency, then you will have to weigh the cost of possible repair against replacement.

I think it unlikely the phase shift will be 180 degrees and constant with frequency, and I highly doubt the fix will be as simple as reversing a couple of wires.

I suspect some component in one channel is introducing a phase shift for some unknown reason.

 

[rijnton]

I think I will gave Yamaha (Holland, where I live), a call on monday and ask what they can do.
Do you happen to know what might cause such problems, assuming that it was not already present when I bought the receiver ?
I ask because I first bought a Theatron Agrippa sound card, to replace an older Creative X-Fi. The Theatron however didn't function well and I could return it and exchange it for the Xonar. The salesman examined the Theatron and told me that one of the components was bent, which probably caused the problem with the sound. What I mean is, could a problem with a soundcard cause problems in the receiver by means of faulty signals or whatsoever ?

 

[TLS Guy]

I think I will gave Yamaha (Holland, where I live), a call on monday and ask what they can do.
Do you happen to know what might cause such problems, assuming that it was not already present when I bought the receiver ?
I ask because I first bought a Theatron Agrippa sound card, to replace an older Creative X-Fi. The Theatron however didn't function well and I could return it and exchange it for the Xonar. The salesman examined the Theatron and told me that one of the components was bent, which probably caused the problem with the sound. What I mean is, could a problem with a soundcard cause problems in the receiver by means of faulty signals or whatsoever ?

I don't think you can assume this fault was present when you bought the receiver, although it might have been.

I don't think the sound card caused the problem. I can't really speculate what the problem might be, this is a most unusual fault. An educated guess might be a feedback circuit round an op amp IC chip in the preamp of the receiver that has changed its time constant, possibly due to a failing cap. However that is pure speculation. Going round the unit with a scope should lead to the general area of the problem pretty quickly. However finding the exact component, or components might be more tricky.

Getting access to test points and working within the crammed in electronics of a modern receiver, is probably not fun at all. If the problem is in the preamp section, it will likely be easier and cheaper to replace that board.

I would see if you can get a tech to run a signal though it and check the phasing between channels with frequency. If the phase angle is 180 degrees at all audio frequencies, then you have a simple cheap fix. Just leave one speaker connection reversed. If you are not that lucky then you have a problem that will cost you money in terms of replacement or repair.

 

[rijnton]

Thanks again for your elaborate help TLS Guy.
Unfortunately I dont know a tech in my neighborhood with a suitable scope. ( I first thought of my neighbor and he has a scope but he told me it is an old, single, one not suited for this job).
Perhaps Yamaha Holland will do it. They are not so far from where I live. I will give them a call and drive to them if they will do it.

 

[highfigh]

Today I noticed a very strange problem with my receiver, although it may exist already a long time, maybe even since buying the receiver.
Because I sincerely hope that one of the experts here can give me some help or advice I registered here.
I am absolutely sure that the wiring from my B&W P4 speakers to my Yamaha RX-V757 is correct, because I double-checked and double-checked again, but the sound is out of phase. I can hear it with a phase test signal and with a mono radio signal as well. The latter is diffuse.
I reset the receiver to factory defaults and ran the setup again. I did not get a warning about being out of phase.
Still the mono sound is diffuse and the test signal reports being out of phase.
I did the test with the following configurations:
1) Test cd in stand-alone cd player to multichannel inputs receiver and to cd inputs. Both report out of phase.
2) Test cd in cd player of pc, connected to multichannel receiver: out of phase
Strange thing is however that when I play the test cd in my pc with digital connection to receiver, it is o.k. and not reporting out of phase.
Because when using the analog inputs the sound is wrong ,with the speakers correctly (at least theoratically) connected, I changed the connectors of 1 speaker. So on one of the speakers + on - and - on +. Everything sounds o.k. now including the test signal, except when using the digital connection. When I ran the setup I now get an out of phase warning.
To summarize: when speakers are correctly connected I get no out of phase warning but the sound is out of phase and when wrong connected, an out of phase warning but sound is fine.
It looks like something wrong inside the receiver but what could it be ?

Regardless of the reputation of the speaker manufacturer, drivers can be shipped to them with the voice coil improperly installed. Do a phase check for each speaker, then check the speaker cables, then re-check the way the cables attach to the receiver.

 

[TLS Guy]

Regardless of the reputation of the speaker manufacturer, drivers can be shipped to them with the voice coil improperly installed. Do a phase check for each speaker, then check the speaker cables, then re-check the way the cables attach to the receiver.

The OP says he has already done a speaker phase check with a battery, and checked and checked his wiring. That strangely does not seem to be the problem.

 

[rijnton]

To be absolutely sure I did a re-check with a 1,5V battery. Yesterday I used an AA battery and although I saw a movement of the woofer it was very slight. Now I used a higher capacity 1,5 mono cell and the movement was much better detectable. Anyhow with - to - and + to + both speakers had a forward movement of the woofer. So the speakers must be o.k.
Btw, on second thought I think it must have started to occur a few months ago. Until a few months ago it stroke me that one of the FM stations that I listen to sounded rather "bassy" (is that the right word ?), probably bad equalizing (?). But the last few months that wasn't the case anymore. Now that I have reversed the wiring of 1 speakers and sound-wise it is more or less in phase again, that station sounds "bassy" again.

 

[DD66000]

Regardless of the reputation of the speaker manufacturer, drivers can be shipped to them with the voice coil improperly installed. Do a phase check for each speaker, then check the speaker cables, then re-check the way the cables attach to the receiver.

The op doesn't have a phase problem when using a digital input, only analog, so therefore, it can't be the speakers, it has to be in the amp.

 

[rijnton]

Maybe it was a bit confusing. In my first post I said that it was only the analog input, but later I reported that it was the digital input as well. Probably I didn't test it correctly the first time.
Nevertheless the speakers are o.k. , according to my testing with a battery.

 

[mtrycrafts]

Maybe it was a bit confusing. In my first post I said that it was only the analog input, but later I reported that it was the digital input as well. Probably I didn't test it correctly the first time.
Nevertheless the speakers are o.k. , according to my testing with a battery.

Did you check all the drivers in the speakers or just the bass driver? If one of the mids or tweeter are out of phase, that could also cause you the issues.
It is just strange that this would start in the receiver's midlife; oh, a mid life crises?

By the way, is the digital and analog inputs are from the same source? Try it with a FM station in mono mode? Does the speaker wires have easy to identify + and - leads on them?