wiring speakers out of phase

[vinyljunky]

adrian from audioflair has recommended i wire the speaker cable out of phase on my speakers red to black black to red he says this works well with the croft amp
who am i to argue he sold me the croft amp he has always given me good advice any one done this to good affect also could this damage my speakers i am trying
this now i cannot make my mind up about the sonic difference

[Rothchild]

It won't do any damage, all the same electons just moving in the opposite direction.

As I understand from previous conversations here Croft amps are phase inverting (ie they output with the signal polarity inverted from the input) so swapping the output to the speakers will simply correct this 'design choice'. What it boils down to is maintaining the absolute polarity of the system (whereby the idea is that a positive pressure wave, coming from a kick drum for instance, which makes the microphone capsule move backwards is ultimately translated to an outward extension of your speaker cone and thus creating the 'same' positive pressure field as the being in front of the kick drum. If your amp inverts the polarity then that signal will be expressed as the cone moving back rather than forward (generating a negative pressure field) so whilst it will still sound like a kick drum it won't be an accurate representation of the signal on the source.

I'm sure someone can explain it better than me but that's about the nuts and bolts of it.

[Ali Tait]

If you swap both speaker leads, your speakers are still in phase (relative to each other).

[vinyljunky]

did not realise the croft was phase inverting it makes sense to reverse the polarity of the cables he must think that a more realistic sound is achieve this way.who am i to argue with glen croft.

[MartinT]

If you swap both speaker leads, your speakers are still in phase (relative to each other).

As Ali says, don't get inverse phase (as you're doing) confused with out of phase, where one speaker is reversed and the stereo image is destroyed.

[The Black Adder]

I thought Croft inverted the phase on his pre-amps too.... Sure I read that on here somewhere therefore if you are using a croft pre and a none croft power amp the speaker outputs should be inverted.

[Ali Tait]

Except some recordings invert phase... :D

[The Black Adder]

lol.. yes, it all seems pointless in some ways. Recordings should state if they were mastered in inverted phase...lol

[hifi_dave]

It gets worse as some mics might be in phase and some out - apparently.

When ever I've played around with absolute phase reversal, it is barely audible if at all and often just sounds a tiny bit 'different' - not better or worse.

[anthonyTD]

When you understand how many Phase inversions the original signal goes through from mic, to mixing desk, to amplification etc,and all the diffrent gain stages in each, you realize that an absolute in phase recording is as rare as a four leaf clover!
As others have said, the most important thing is to make sure both speakers are wired the same, and experiment with them both either way round, some rooms react more positively with them one way around than the other, however, it will be down to the over-all system and room environment, and to some extent' individual preference as a whole' as to whether which way round is right or wrong.:)
A...

[DSJR]

Some systems are sensitive to this, although most passive speakers are all over the place anyway. I've heard modern Croft stuff (pre and power) wired properly as labelled on the rear and that's how I'd use it myself. One of the simpler 25 preamps on its own may be a different matter.

Don't bother your head with it is my recommendation - hiding to a neurotic nothing in my experiences doing this ;)

[YNWaN]

Except some recordings invert phase... :D

Yes, and multi-track recordings often pay no attention to absolute phase so it is common to find some instruments recorded in reverse phase compared to others.

[Barry]

I wrestled with absolute phase in the first part of my post: http://theartofsound.net/forum/showthread.php?11839-Absolute-phase-and-integrated-cartridge-arms. Subsequent replies confirmed what has been mentioned, that with the use of multi-microphone and multi-tracking, absolute phase is lost. Strangely, the Americans seem be sensitive to the phenomenon.

[Mr Kipling]

The Meridian 207 cd player lets you switch it. The results can vary from track to track simply due what others have already stated in that phase of individual instruments can be all over place. The (small) differences I've noticed have been in terms of focus and leading edges.

[Marco]

I thought Croft inverted the phase on his pre-amps too.... Sure I read that on here somewhere therefore if you are using a croft pre and a none croft power amp the speaker outputs should be inverted.

Hi Joe,

That's absolutely correct. It makes a big difference to the performance of the older Croft preamps, such as you and I use. The main reasoning behind phase inverting is that it cuts out a whole gain stage in the circuit, which is normally required with amps that don't invert the phase, so a shorter signal path is obtained, and subsequently greater fidelity.

Therefore, any system that contains a Croft preamp, should have the polarity of the speaker cables reversed, either at the amp or speaker end :)

Marco.

[hifi_dave]

Croft power-amps also reverse the phase.

[Marco]

Yup, so if you use a Croft power amp, then reverse the polarity of the cables at the speaker end. All of this only matters of course if you can hear the difference :)

Marco.

[kininigin]

Yup, so if you use a Croft power amp, then reverse the polarity of the cables at the speaker end. All of this only matters of course if you can hear the difference :)

Marco.

Or you use active speakers and so have no cables to reverse the polarity ;)

[Mr Kipling]

lol.. yes, it all seems pointless in some ways. Recordings should state if they were mastered in inverted phase...lol

Hey! Joe!

Where you going with that gun in you hand? . . .

Ba-Doom. . . Ba-Da-Ba-Da-Doom. . .

[Covenant]

What do you know, a free tweak that works!

[Rothchild]

I would contest as to whether absolute phase (or polarity to be correct) is 'lost' certainly it might not always be understood and probably is a relatively low priority to most engineers recording complex, multimic, multitrack records that aren't in the 'authentic documentary' style. Indeed, part of the art of multimic recording is the compromise of phase issues (not all the mics are the same distance from the source so the wave arrives at the mic at a different phase (phase being a time based phenomena)) which nudges concerns about absolute polarity down the line somewhat.

Inverting polarity is a regular thing to do on certain instruments, if you're tracking a snare with top and bottom then it's correct to invert the polarity of one of the mics because with them pointing each other with the instrument inbetween their diaphrams are moving in opposite directions so the summed signal will have a degree of cancellation, inverting the polarity is the solution this is not 'losing' phase but maintaining it IMO.

Anyway as most agree it's of trivial difference, some people find the effect more pronounced than others but it's free and easy to try, if you don't like it you can switch back and if you do, winner!

[vinyljunky]

whatever the science since reversing the polarity i have noticed a lot more detail and a wider soundstage particularly with vinyl but also with cd i'm a believer as the monkeys would say

[Marco]

Regardless if anyone can hear a difference or not with reversing polarity, the reason below is surely a sound one for incorporating it into an amplifier design in the first place:


The main reasoning behind phase inverting is that it cuts out a whole gain stage in the circuit, which is normally required with amps that don't invert the phase, so a shorter signal path is obtained, and subsequently greater fidelity.


This was pointed out to me recently by Nick (lurcher). Therefore, one can appreciate why Glenn chooses to adopt this procedure in the Croft amps.

In my system, where only a phase-inverting Croft preamp resides, the sound is quite different (markedly inferior) if I don't reverse the polarity of my speaker cables. The effect is NOT a subtle one, and it applies with all recordings.

Marco.

[MartinT]

My old JBL L100-T speakers were inverse phase. I always reversed the speaker cables when running them, and they sounded better that way to my ears (the rest of my system preserved phase).

Speaker phase is easily checked with a 1.5V battery across the terminals - positive to red should result in the bass driver coming out of the speaker. If it goes in, it is wired inverse phase.

[Covenant]

I know Glen Croft is not the most loquacious of gentlemen but does he mention the inverted phase anywhere?

[Marco]

Hi Jerry,

Not to my knowledge, as I don't even think an instruction manual is provided with new Croft equipment. However, you can take it as read that ALL Croft gear is phase-inverting.

Paul Hynes also does the same with his MC head amp.

Marco.

[anthonyTD]

If you inspect the schematics of most amplifiers and pre-amplifiers, you will notice that many have the signal coming out inverted with respect to the signal going in, this is determined by the amount of gain stages, and the way that each gain stage is used and connected to the next, and so on.
However, most manufacturers pay no attention to this, and feel no need to inform the end user, after -all there have been so many phase changes in the recording process of the original signal' that in theory it should only make a difference to the end user, their system, and their particular environment etc,ie; if they feel their system sounds better with their speakers connected one way around to the other. Then of course you have the issue of the speakers themselves, ie; a lot of them have the high frequency units configured out of phase with the main mid and bass units etc, etc, and that opens up another can of worms.
At the end of day, try it, if its an improvement, leave it, if not, reverse it back.:)
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