Speaker Phase.

[walpurgis]

Does it matter if your speakers are connected in phase, i.e., positive lead to positive terminal? After all, some manufacturers deliberately wire their speakers 180 degrees out of phase. Test a pair of older Tannoys and the chances are that you will find they are not wired positive to positive terminal. Just use a small low voltage battery across the terminals with + to +. The bass cone should move slightly forwards, if in phase.

[Reffc]

Does it matter if your speakers are connected in phase, i.e., positive lead to positive terminal? After all, some manufacturers deliberately wire their speakers 180 degrees out of phase. Test a pair of older Tannoys and the chances are that you will find they are not wired positive to positive terminal. Just use a small low voltage battery across the terminals with + to +. The bass cone should move slightly forwards, if in phase.

Not true with Tannoy DC's where if "correctly" phased, the bass cone should move inwards, the reasons are given below:

Some Tannoys are not wired in phase between input and output of the crossovers due to the crossover employed. 2nd order crossovers induce 180 degrees of phase shift between input and output.

As I understand it for a simple Butterworth-aligned 2nd order networks, the stop-band phase shift of a woofer is -180 degrees and that of the tweeter is +180 degrees (both 2nd order). At the crossover point, the phase shifts are -90 and +90 respectively. That's why with 2nd order networks, you invert the phase of the tweeter, because the woofer is at -90, the tweeter is at +90 and the difference is 180 degrees, or complete cancellation. Either that or the bass unit phase is inverted. The Tannoy HF section is 2nd order for HPD/LZ drivers. For the LZ/HPD I think that the tweeter is connected with positive polarity (ie in phase which is certainly how I've built my crossovers). The way the 4-pin connector is wired means that if connecting a small 1.5v battery across the input terminals to the crossovers, the bass unit moves inwards (ie 180 degrees out of phase) and the tweeter is at zero degrees. It looks like what Tannoy have done is to invert the woofer with respect to the tweeter to account for the 2nd order network.

Swapping polarity at the speaker inputs won't of course affect the absolute phase relationship between tweeter and woofer. However, both speakers must obviously be the same.

To hear if there's any real difference in SQ, you could invert input polarity ( some amps have a phase inversion facility) but bear in mind that it will only make a positive difference (pun intended) if the recording itself is phase inverted. I think that some were were for some odd reason, hence the facility on some amps.

[Rare Bird]

I remember an article in 'Hi Fi For Pleasure' mag donkies years ago regarding using a Quad '303' wired out of phase!

[icehockeyboy]

Fwiw, once when I had my PMC's tweeter upgraded, I inadvertently somehow wired them out of phase, and was astonished, not at the lack of bass or other aspects associated with wiring incorrectly, but with an amazing holographic effect, and instruments seemingly coming from behind me!

Sadly that went when I wired them in phase.

[anthonyTD]

In simple terms,
The two drivers are connected out of phase in an effort to maintain a flat frequency response at the cross-over point!
As far as over-all phase is concerned, some people prefer the speakers connected the opposite way around ie; positive from amp connected to negative of speaker [on both speakers obviously] i think a lot [IMHO] will depend on the room environment and the absolute polarity of the equipment being used for a preference either way, the only way to know for sure which is right for you, is to try it.:)
A...

[Reffc]

In simple terms,
The two drivers are connected out of phase in an effort to maintain a flat frequency response at the cross-over point!
As far as over-all phase is concerned, some people prefer the speakers connected the opposite way around ie; positive from amp connected to negative of speaker [on both speakers obviously] i think a lot [IMHO] will depend on the room environment and the absolute polarity of the equipment being used for a preference either way, the only way to know for sure which is right for you, is to try it.:)
A...

True, but I think it also depends on the recording too. There was an article in one of the mags a while back on phase inverted recordings (ie as in why they were done this way) but I haven't got a clue how many there are out there like that so as you say, some people prefer overall phase reversed. Personally, I hear little difference doing this in most cases.

[YNWaN]

Some amplifier topologies inherently invert absolute phase.

As Paul (Reffc) states, second order crossovers invert the phase and it is common to find that this has been accounted for by reversing the phase of one of the drive units.

Absolute phase is not (or very rarely) accounted for in the recording process and it is common with multi-tracked recordings to find some instruments recorded in positive and some in negative phase relative to each other.

Some claim that absolute phase is important (some manufacturers even produce electronics with phase inverting switches) - but much of the actual scientific evidence suggests that the ear cannot hear absolute phase.

[Mr Kipling]

Years ago it was suggested to wire one channel out of phase with a cartrdge and reverse the speaker connections of that channel. Bit less of a drain on the power supply.

[Jonboy]

I had a pair of Kef 105.3 that I replaced the tweeters on to the latest spec , when I tried them they sounded awfull so natually check all my wiring over and over again still to no avail so I put them away I happened to come across the wiring diagram one and noticed that the tweeters are actually wired out of phase so stripped them apart and saw that I had natually wired them in phase, a quick swap around and hey prestow they were singing again

[YNWaN]

Jon, that is a common mistake. Both pairs of Yamaha NS-1000M's that I stripped had their drivers wired wrongly, for the very reason you describe. Logic would suggest that the positive wire goes to the positive connector - but often this is not the case with crossovers (2nd order any way). It would be possible to include this on the crossover board, but I've not seen it done this way - instead manufacturers just reverse the wire connections at the actual drive unit. This is fine as long as you have either made careful note of exactly which wire goes where or are familiar with the crossover design/layout (which many are not).

[Mr Kipling]

My Meridian 207 allows the phase to be switched and when I've tried it most of the time the difference is next to nothing with normal being slightly more focused. There is the odd track that does sound better focused when reversed. I've heard greater differences from cables and did often wonder why Meridian chose to offer the facility.

[YNWaN]

They wanted to include a feature (at the time) that would appeal to the American market - that's it.