Out-Of-Phase Speakers

[highfigh]

The sound wave is going the wrong way so I would say that is less efficient. So if you wire all your speakers out of phase there would be no difference since there would be no phase cancellation?

As long as the room has reflective surfaces, two or more speakers are sending some common information and you can't be at exactly the same distance from both sound sources, phase cancellations will always exist. If you have used an RTA and saw a deep dip in the response and couldn't EQ it out, it was due to a phase cancellation. Could be from the mic placement, could be from a crossover (12dB/octave reverses the phase of the driver it feeds), a driver could be mis-wired/mis-labeled but it is from a phase cancellation. If there are many dips like this, it's usually because the room has multiple reflections.

 

[mulester7]

could be from a crossover (12dB/octave reverses the phase of the driver it feeds)

.....HighFigh, could you take that further?....not being negative at all....I'm curious how you get that.....

 

[mulester7]

If you put them out of phase both speakers it will simulate sound coming behind you. Its pretty neat actually. I did this in the day when I used my Lafayette and Marrantz receivers. Canceled the lows out, but if you put another pair in phase what neat stuff happens!

.....this is the most encouraging thing posted yet....Joe has experienced what I'm going to propose.....

 

[Votrax]

I understand that a positve impulse should make the speakers move out but have you ever measured the output from speakers with an RTA or SPL meter? It doesn't show a difference unless it's only one speaker or driver and phase cancellations are occurring.

I didn't say they will sound the same. In fact, I have posted in more than one thread that it sounds different but the acoustical energy is the same. I have reversed the polarity of my speaker wires on every system I have owned, in every place I have lived. in some rooms, it sounds better, some worse, but the difference has always been audible.

I agree

 

[mulester7]

I didn't say they will sound the same. In fact, I have posted in more than one thread that it sounds different but the acoustical energy is the same. I have reversed the polarity of my speaker wires on every system I have owned, in every place I have lived. in some rooms, it sounds better, some worse, but the difference has always been audible.

.....I just saw a vision of Glory.....

 

[Alex2507]

.....I just saw a vision of Glory.....

A makes sense answer that agrees with your perceptions ... you must be very proud.

 

[mulester7]

A makes sense answer that agrees with your perceptions ... you must be very proud.

.....Alex, I didn't like that other post so I killed it....I am quite proud of HighFigh as being one who experiments with what they have, seeking the best sound obtainable....now, that's better....ya'll are probably sick of me trying to be funny....this is a good thread if you care about the sound-quality of your Home Theater....I think what I'm doing stands to improve any 5.0 or 4.0 system.....

 

[Alex2507]

The deleted post was funny. I don't think I would be able to tell you which way I like better due to a lack of being able to compare the difference quickly enough. I suppose that I could compare my mains in 2 channel stereo mode with banana connectors but even then I use bass management to cross to a couple of subs in mono and then would I run those in 180 degree phase shift and then take measurements ...

... you people are trying to ruin me!

Runs from computer ...

 

[mulester7]

Runs from computer ...

.....Chases Alex waving a banana.....

 

[mulester7]

.....I'm not trying to draw this thing out, or make it some kind of drama....I've been waiting on a reading to be taken, and it doesn't really matter to me if it's taken or not....here's what I'm doing and calling it.....

.....I'm cross-wiring my surrounds out-of-phase, and using bridged amp channels to push them....I'm using bridged channels from a Mac MC58, which has 8 channels rated 30 at 8, a multi-channel....but, specs of the 58 say 100 watts at 8 when two of the channels are bridged....why didn't it give a rating at 4?....don't kid yourself, nothing magic is happening....the 8 ohm speakers are still getting hit with 4 ohm bullets, but the bridged-effort can't be rated 4-ohm stable, because of small amp-sections....anyhow, the impedance-change of the bullets will change the impedance of what's cast from the 8 ohm elements of the speakers....I've already established the only place I want an impedance-change is coming from the indirect, and this certainly fits the bill and personal requirements.....

.....yes, I have my surrounds cross-wired out-of-phase with bridged amp channels pushing them....the surrounds are being tastefully applied on everything, and I love the result....I didn't need more watts at all....I needed a change of impedance, and authority given to the effects of cross-wiring.....

.....I hear a speaker go more efficient when it's cross-wired out-of-phase....measurements taken even yet, may bring that theory down hard, but I'll just be thinking, ok, my theories are blown out of the water, but I guess I'll just keep listening this way because I love it's realism.....

.....one needs two 2-channel amps that will bridge, or a multi-channel amp where 2 sections will bridge....I'm thinking about that smallest Behringer as what would be good to have a couple of.....

.....this would be best applied using front mains, center, and surrounds of the same line, and you really need separate gains on the amps to achieve balance from the surrounds.....

.....the surrounds end-up volumed roughly the same spl-levels as before, and a little less than before is probably where you'll settle....marvelous effect on the front soundstage....running bridged channels to the surrounds without cross-wiring the speaker brings crispy authority to the front soundstage, but running bridged channels "and" cross-wiring, brings crispy honey poured all over the front soundstage, and the realism-change on the front soundstage is staggering.....must hear to understand.....

.....my speakers up front honestly have seemed to go up in value as per sound-quality, imo....in my Daughter's and ex's opinions also....they hear fine, know stereo stuff well, especially my Daughter, and both said they heard a big difference once they got used to hearing the surrounds, as I turned them on and off at the multi-channel amp.....

.....if interested, rig it up, set the levels of the surrounds as best you can honoring the front soundstage as before, and go to your listening position....a willing wife can then fine-tune the surrounds as you sit in your spot, and she can turn the surrounds' amps off for you to hear what you'll probably not want anymore.....

.....that's it, nothing magic....just an application of a different impedance from the indirect, and it sounds awfully good to me....I went through a larger spill in a thread somewhere else about this concept, and no one posted as having tried it at all, or even posted to the concept, as to what it would bring in their opinon....oh well.....

.....important words....tastefully applied....whew, sorry about the length....anyone making it this far, thanks....no proof.....

 

[mulester7]

I went through a larger spill in a thread somewhere else about this concept, and no one posted as having tried it at all, or even posted to the concept, as to what it would bring in their opinon....oh well.....

.....I mean nooooothing....(cricket).....

 

[mulester7]

.....most of us get stressed at times....that's why I keep this one in my favorites list....this Guy has hypnotized me with his singing all his career....I guess singing is ok at an audio-site?.....

http://www.youtube.com/watch?v=YcuLZxyhOoI

 

[Alex2507]

....I guess singing is ok at an audio-site?.....

At this audio site it's encouraged. My mind must be shot though. At first I though, 'Garth Brooks is white'. Then I thought, 'this doesn't sound like a drinking song'.

Over in Musical Goodness they have a couple of threads that you might enjoy:

http://forums.audioholics.com/forums/showthread.php?t=6616

and

http://forums.audioholics.com/forums/showthread.php?t=52328

Your level of enthusiasm has by far eclipsed my own involvement and experience with audio. I'm getting lost in the whole bridged 4 ohm bullet thing but if I were you I would be PM'ing PENG. He's an electrical engineer with a real handle on amp technology.

Now for the comments I can make from my level of involvement. I thought that impedance was a characteristic of the speaker. When applied to an amplifier as a setting, I thought it was an ampere limiting function. See? I can't really hold an interesting or informed conversation on this topic but I am keeping an eye on you and this thread to see what shakes out.

 

[Midcow2]

sub frequencies-- phasing more important

As said before 8ohms is 8 ohms whether in phase or not.

But a couple of other things, remember the impedance varies with frequency due to inductive and capacitance in additon to resistance, so 8 ohms is only an average of nominal impedance.

However, more important about phase is wavelength. If the wavelength is very short as in high frequencies, then even with "golden" ears you will not be able to discern any difference. Where the phasing becomes important is with the lower subwooofer frequency. That is why subwoofer placement, "walking the sub" is so important.

Good Luck,

MidCow2

 

[Alex2507]

That is why subwoofer placementis so important.

The placement of Ronnie's 3 subs with their 6 drivers is of importance to the next county.

 

[highfigh]

However, more important about phase is wavelength. If the wavelength is very short as in high frequencies, then even with "golden" ears you will not be able to discern any difference. Where the phasing becomes important is with the lower subwooofer frequency. That is why subwoofer placement, "walking the sub" is so important.

Good Luck,

MidCow2

The last sentence is the reason I wonder why amplified subwoofers only have a phase switch, which reverses the woofer's polarity, instead of a control that allows the phase to vary. The latter makes time alignment much easier.

 

[ee4hire]

As mentioned above, 8 ohms is 8 ohms. This is the DC impedance of the speaker and will be the same which ever polarity you hook up the ohm meter. Just to be back up my statement with a measurement, I put my DMM on my Polk RT-800i (two way speaker, one tweeter, two low range speakers) and confirmed the same DC impedance both ways. The good thing about this is that you can't damage your amplifier by connecting "backwards", the amp will have the same DC load either way. Remember, the signal to the speaker is AC, so if the DC impedance were polarity dependent, I think the results might be strange with the different current that would result on each phase of the signal, i.e. if the positive excursions drew more current than the negative excursions.

If we talk about AC impedance, which will vary with frequency, then there is no polarity, so the question is moot.

Now, having said all that, this doesn't necessarily mean that the speakers will sound the same with either polarity connection. I think the differences will be very subtle, but it is possible there will be differences. One reason could be if any polarized components are used in the crossover networks, not likely, but possible. Also, circuits tend to be built with grounds as planes or shields, so connecting the active signal to the such a ground in the circuit could have unexpected effects. There could be other things that make differences in each particular crossover network or speaker. I expect that the differences would beyond what my ear could distinguish, but I'm sure there are those who could.

Since I don't know what is in my speaker without ripping it apart, I always connect my speakers with the "correct" polarity, but if you want to experiment on your own, you shouldn't need to worry about damage to your amp when you try it.

 

[Midcow2]

Actually ...

As mentioned above, 8 ohms is 8 ohms. This is the DC impedance of the speaker and will be the same which ever polarity you hook up the ohm meter. Just to be back up my statement with a measurement, I put my DMM on my Polk RT-800i (two way speaker, one tweeter, two low range speakers) and confirmed the same DC impedance both ways. The good thing about this is that you can't damage your amplifier by connecting "backwards", the amp will have the same DC load either way. Remember, the signal to the speaker is AC, so if the DC impedance were polarity dependent, I think the results might be strange with the different current that would result on each phase of the signal, i.e. if the positive excursions drew more current than the negative excursions.

If we talk about AC impedance, which will vary with frequency, then there is no polarity, so the question is moot.

Now, having said all that, this doesn't necessarily mean that the speakers will sound the same with either polarity connection. I think the differences will be very subtle, but it is possible there will be differences. One reason could be if any polarized components are used in the crossover networks, not likely, but possible. Also, circuits tend to be built with grounds as planes or shields, so connecting the active signal to the such a ground in the circuit could have unexpected effects. There could be other things that make differences in each particular crossover network or speaker. I expect that the differences would beyond what my ear could distinguish, but I'm sure there are those who could.

Since I don't know what is in my speaker without ripping it apart, I always connect my speakers with the "correct" polarity, but if you want to experiment on your own, you shouldn't need to worry about damage to your amp when you try it.

Just a little clarification:

Resistance is the pure DC part of impedance in your terms. Impedance is the hypotenuese of either inductance or capcitance and resistance:

It is also the reason there is a power factor and that KVA is typically a higher value that the actual power.

Actually it does make a difference. Polarity is typically 180 phasing ( a full wave period is the same as the number of degrees in a circle 360 or 2 Pie radians. Two sounds exactly 180 degress out of phase add to zero (see figure following). That is how noise cancellation takes place.

Look at the latest Totota Crown cancellation system.
http://www.engadget.com/2008/09/08/noise-cancelling-toyota-crown-zeroes-out-sounds-at-head-height/

Later,

MidCow2

 

[mulester7]

Now, having said all that, this doesn't necessarily mean that the speakers will sound the same with either polarity connection. I think the differences will be very subtle, but it is possible there will be differences.

.....thanks for the response, EE4Hire, and I assure you, the difference is much more than just subtle....I said earlier this phrase would be said again....must hear to understand.....

.....I don't expect anyone to go out and purchase two 2-channel amps just to try this as times are tough, but surely, some Guys here have a 5.0, 5.1, or 5.2 system, and a couple of two channel amps that will bridge not being used.....

.....Craigsub, you used to have stereo equipment filling a couple of floors of your house, maybe you could try this?.....

 

[mulester7]

Actually it does make a difference. Polarity is typically 180 phasing ( a full wave period is the same as the number of degrees in a circle 360 or 2 Pie radians. Two sounds exactly 180 degrees out of phase add to zero (see figure following). That is how noise cancellation takes place.

.....Midcow, killer post with lots to look at, but I'm not talking phase-control for bass-seperates....I really appreciate all responses, but, once again, must hear to understand.....

.....my front soundstage has 2 or 5 times more realism than before, but how do you measure that?.....