What dictates a system's phase?

[WullieD20]

Maybe sounds like a strange question, but I've been doing this 'hi-fi' thing for quite a while now and I'm a bit stumped with this particular anomaly!

I have always connected a system up as normal with red to red and black to black in the case pf the speakers (and ensuring that all other interconnects were connected appropriately as required), the system always performed perfectly after setting everything up.

I also own an old Shure system test record that I haven't put to use for many years, as generally everything operates perfectly and I would normally hear obvious problems. However, having recently built a plinth for a friend's Garrard 401 and also constructed the tonearm interconnect, I set about testing all aspects fully. "Ah, I know. I'll put the old Shure test record on and ensure everything is in order". Only to find my system was playing 'out of phase' (according to the disc)! Swapping the leads to one speaker not only sorted the problem, but brought the system into focus and raised the question as to how this can happen when everything is connected properly? I have to comment at this point that when playing music in the 'out of phase condition' everything appeared to sound okay with distinct separation between left and right channels and a perfectly believable sound stage.

Suspecting something internal could be a problem with the amps or the speakers, I set about changing the speakers and testing again - same result! I then changed the amp and got exactly the same result.

So where in my system is there a problem that causes the system to play 'out of phase' when all the connections are connected appropriately, regardless of speakers or power amp(s)? Very strange? Or otherwise?

Any contributions to resolving this situation would be most gratefully recieved. Cheers

Gordon.

[Filterlab]

Is the tonearm/cartridge wired correctly?

[WullieD20]

Is the tonearm/cartridge wired correctly?

Yep. Been tried with three separate TTs.

In the middle of stripping the whole system down now and doing a spring clean on all connections from mains right through interconnects and speaker cables. (Probably long overdue anyway!).

[Filterlab]

Looking for the obvious stuff here...

Is the red/black termination on the end of one of the cables incorrectly attributed?

Have you tried different speaker cable? Different interconnects?

[walpurgis]

If you've done everything right and the system sounds fine, why worry. I certainly wouldn't assume that test records are 'right'.

(if you had Tannoys and did the battery test, some of them would leave you flummoxed, as the cone moves backwards when connected to positive)

[Filterlab]

If it sounds ok ‘out of phase’ then what validity does the content of the record have?

[WullieD20]

If you've done everything right and the system sounds fine, why worry. I certainly wouldn't assume that test records are 'right'.

(if you had Tannoys and did the battery test, some of them would leave you flummoxed, as the cone moves backwards when connected to positive)

That's exactly what my son suggested. And I think I got to the stage that I'd listened to it so often with different components and different cables, I'm beginning to doubt my own hearing! I'll wait till I get the system re-assembled and get another pair of ears to evaluate.....


If it sounds ok ‘out of phase’ then what validity does the content of the record have?

Would probably agree...... see above. I'll push the doubts aside until I get the system re-built. Strange how you can get a paranoid when something happens that is not familiar.

Thanks for the suggestions.

[Firebottle]

In the 'in phase' mode is the sound focused right in the middle?
Then in the 'out of phase' mode is the sound a bit spread out and not pin point focused in the middle?

That should be reasonably easy to differentiate. Assuming the cartridge is wired correctly, it sounds as if it is if you have tried 3 decks, then it could be that one of the speakers is actually connected out of phase in the speaker.
Alternatively one of the outputs in the amplifier is connected out of phase, though I think this pretty unlikely.

[Filterlab]

Would probably agree...... see above. I'll push the doubts aside until I get the system re-built. Strange how you can get a paranoid when something happens that is not familiar.

Thanks for the suggestions.

Always trust your ears over measurements. :)

[Pharos]

You can check various portions of the signal path using tone, maybe 1kHz tone put into L and R inputs simultaneously, and with your speakers next to each other, listen from a distance.
If they are in phase they add, but out of phase considerable cancellation will occur. You can also use hum, (carefully), to achieve the same thing.

[WullieD20]

In the 'in phase' mode is the sound focused right in the middle?
Then in the 'out of phase' mode is the sound a bit spread out and not pin point focused in the middle?

That should be reasonably easy to differentiate. Assuming the cartridge is wired correctly, it sounds as if it is if you have tried 3 decks, then it could be that one of the speakers is actually connected out of phase in the speaker.
Alternatively one of the outputs in the amplifier is connected out of phase, though I think this pretty unlikely.

My original suspicions exactly, despite having the system untouched (altered in any way) for quite some time now.

I did a lot of research into the speaker internal wiring, but virtually excluded that before attempting to open them up. It was also going to be very unlikely with the Ear Yoshino 509 power amps.

Having now stripped the whole system apart (no mean feat!) and cleaned, checked and refitted everything I now am beginning to question my sanity!!!! :scratch:

The obvious distinction between in and out of phase with the Shure test record has now disappeared without discovering anything specific wrong (and sounding exactly as it should)! All connections are as they should be (red/red and black/black etc etc) and the system is back to normal and has come to life with fresh vigour.

Having tried all I knew, as described in the original post, and all the suggestions above, I am somewhat confused although extremely happy to have eliminated something that appeared to be clearly wrong. So, no answers that conclude the thread apart from my own ears and some unusual mistrust of a test record.

Thanks to everyone for their input and suggestions, much appreciated,

Cheers,

Gordon.

[Pharos]

Since it now measures correctly, there is no error on the test record, the variable has been corrected with what you have done, but it must be annoying not to know what has happened.