I wanted to ask

[aviv]

If I have all of my speaker cables from my amp to my speakers in the correct + and - then is it still possible to get phase problems.

Im totally confused, I believe I am in a sticky phase rut of doom...

I have my Denon amp into the JBL speakers, when I sit dead in the centre of the speakers the bass seems to be non existant but when I move to either side of the speakers the bass becomes dominant.

Im pretty sure this is a phase issue but :S what the...

So my question still stands, are there phase problems if all of the speaker cables are inserted correctly ( + and - )

Thanks

Aviv

[suprstar]

I'm no expert on this, but a few q's to think about: If you switch the +- on one speaker, does it sound better? Could it be that your room isn't good acoustically, and you have a huge null or void or something at your mix position? Are you sure your phase probs arent caused by your mic'ing techniques?

[aviv]

lol nah dude, im not listening to my recordings im talking basics.

My last set of speakers where the KEF Q series bookshelfs and they were great. These JBL's i have now are even nicer but i just wanted to know if having the cables the wrong sides which either blow my gear(assuming its carrying current) or provide phase problems.

thanks anyway g
Aviv

[SouthSIDE Glen]

Originally Posted by aviv

If I have all of my speaker cables from my amp to my speakers in the correct + and - then is it still possible to get phase problems.

Im totally confused, I believe I am in a sticky phase rut of doom...

I have my Denon amp into the JBL speakers, when I sit dead in the centre of the speakers the bass seems to be non existant but when I move to either side of the speakers the bass becomes dominant.

Im pretty sure this is a phase issue but :S what the...

So my question still stands, are there phase problems if all of the speaker cables are inserted correctly ( + and - )

Thanks

Aviv

That sound more like the bass modality of your room, that at your listening position there is a bass null where your bass frequencies are cancelling each other out.

Bass traps in the corners will help with that. Possibly a new configuration in your room where your listening position is moved could help as well, (but only after taming your modes with some treatment.)

G.

[aviv]

I understand where your coming from but my last speakers proved no problems in this field at all.
Il find out tomorow after i buy some new cables to make sure its all wired correctly.
Thanks G
Aviv

[NYMorningstar]

What you are talking about is polarity (+ or _ ) which is basically the direction the electrons are flowing. If you have them reversed that would result in being 180 degrees out of phase which could be your problem or as others suggested it could be the room.

[dementedchord]

if you were careful with setting up the speakers and we're listening to say a cd... and your hearing this ... it's a room problem... the likelyhood of 1 of the interconnects to the cd somehow being wired wrong on one is basicly nil... and the odds that the amp is inverting onw channel and not the other is still lower...

[aviv]

Originally Posted by NYMorningstar

What you are talking about is polarity (+ or _ ) which is basically the direction the electrons are flowing. If you have them reversed that would result in being 180 degrees out of phase which could be your problem or as others suggested it could be the room.

I think you hit it on the head,(I presume) i mean ive had some awesome speakers in here and for me not to notice a null seems slightly odd. I mean i sit in the same spot.
So nothing will happen if i mess around with the cables in the sense that my gear wont start a forest fire? because they are carrying electrons as you said.
cheers
Aviv

[SouthSIDE Glen]

Originally Posted by aviv

I think you hit it on the head,(I presume) i mean ive had some awesome speakers in here and for me not to notice a null seems slightly odd. I mean i sit in the same spot.
So nothing will happen if i mess around with the cables in the sense that my gear wont start a forest fire? because they are carrying electrons as you said.
cheers
Aviv

You don't - or shouldn't - just "mess around". Speaker wire is ALWAYS coded in one way or another to let you know which conductor is which. Even cheap-ass zip cord or lamp cord from Radio Shack is either color-coded by the color of the metal (pure coppor-color braid vs. mixed copper and silver braid) or by one side of the insulation being smooth and the other being ridged.

If you're using 1/4" or XLR cables, then remove the outer shell and look at the insulation colors of the wires inside and make sure they line up the same on both ends. If not, then it's an easy fix to re-solder them. If they are RCA cables, then your wire is probably not the problem, but the only way to know would be to replace them both.

You could be switching polarity somewhere else along the line too. Make sure it's not switched in any of your DAW racks or in any of the other cables in your signal path.

I still suspect your room.

G.

[aviv]

im using speaker cable because the speakers arent powered. I can see where your coming from G but its the fact that ive used the KEF's in here and the bass was crystal so i have a real suspision its the polarity, BUT
il tell you guys tomorow seeming as you have all enlightened me plenty on this fine night,
i shall report!

Thanks
Aviv

[whjr15]

Originally Posted by aviv

when I sit dead in the centre of the speakers the bass seems to be non existant but when I move to either side of the speakers the bass becomes dominant.


Aviv

That right there should tell you that its not the wiring. If wiring was the problem from the start, how would the bass just magically appear when you moved to the side?

[pipelineaudio]

Originally Posted by whjr15

That right there should tell you that its not the wiring. If wiring was the problem from the start, how would the bass just magically appear when you moved to the side?

It often will

In the time it took for him to post this, he could have flipped one of the cables to see.

If its a real strong in your face null as you rock your body from side to side, its hard to imagine it being the room, it sounds like speaker polarity.

If its not that drastic, then chances are good that it could be the room

[chazba]

Maybe one of the boxes is wired backwards...hmmm...let me guess. Were they made in China? You can check polarity by touching a 9V batt acress the spkr wires (after disconnecting from the amp) Watch the spkr cone. Test one , then the other > If the batt connection is the same for both, they should move in the same direction. If they don't....


chazba

[kubeek]

Originally Posted by chazba

Maybe one of the boxes is wired backwards...hmmm...let me guess. Were they made in China? You can check polarity by touching a 9V batt acress the spkr wires (after disconnecting from the amp) Watch the spkr cone. Test one , then the other > If the batt connection is the same for both, they should move in the same direction. If they don't....


chazba

9v is quite a lot voltage for expensive speakers, esp with fresh battery! Don´t do it!

1.5v is more than enough.

[dementedchord]

Originally Posted by kubeek

9v is quite a lot voltage for expensive speakers, esp with fresh battery! Don´t do it!

1.5v is more than enough.

bullshit.... 1.5 is enough granted... but 9V wont kill anything... ya gotta remember that alot of amps can swing up to+/- 60V even for cheap ass home stereos... and you dont leave it on long anyhow... ya just pop it and watch that they move the same direction...

[kubeek]

60 volts peak into 4 ohm speakers is 450W (225W into 8ohm). Definitely not a home stereo.

The 9v battery, when you leave it connected for any longer than just sratching the terminals can produce cca 25W into 4ohm. That is more than enough to burn some voicecoils, because speakers are not designed for DC.

[NL5]

Originally Posted by aviv

but its the fact that ive used the KEF's in here and the bass was crystal

You are listening from the exact same position, right? Where were the woofer in relation to the floor and ceiling? Where are they now?

You have modal problems in your room. I can 100% guarantee that. Is that 100% of your problem? Maybe.

[aviv]

well would you have guessed!
it was a phase issue. I bought some decent speaker cables, ensured the polarity was correct and there we go. It all came together.

I mean no doubt i would love some bass traps in my room for a few of the corners but that wasn't the main problem that i could clearly hear. It was freaking me out because I knew these JBL's where rather good and what I was hearing could not be correct.

But luckily its all come together. Thanks for all your advice but im glad i learnt that pase issues are dangerous, ensure that you know about them before you plough through with your adventures in home recording and such.


Thanks

Aviv

[pipelineaudio]

20 points for me


I have seen more than once, speaker cables bought at the same time, from the same manufacturer, same model, with varying polarities

But now, like the other guys said, go the rest of the way and get the room acoustics as good as you can afford.

It won't be as obvious an "aha" at first but it WILL be to your finished mixes

[SouthSIDE Glen]

The question I have is if it were a polarity reversal, why were only the bass frequencies affected?

G.

[kubeek]

Because those cancel at wider part of the "center" than higher frequencies?

[SouthSIDE Glen]

Originally Posted by kubeek

Because those cancel at wider part of the "center" than higher frequencies?

I can see what your saying, but here's a couple of sample numbers:

1kHz equals ~13 inches full wavelength
2kHz = ~7 inches wavelength
5kHz - ~3 inches wavelength

Even if we assume that at least a 75% phase shift were required to have audible levels of attenuation, we're talking a "center" that's 3.25" wide at 1kHz, 1.75" wide at 2kHz, and .75" wide at 5kHz. All quite large enough to notice, though perhaps only on one ear at a time. Perhaps more important and evident would be that there will be just the opposite - coincident peak modes - just a half wavelength away for very definite apparent comb filtering at those frequencies.

I'm not saying that it wasn't a polarity issue, it apparently was. I'm just saying (I guess?) that we must have been given a incomplete description of the symptoms, because just a loss of bass wouldn't seem to indicate a polarity problem.

G.

[aviv]

Originally Posted by SouthSIDE Glen

I can see what your saying, but here's a couple of sample numbers:

1kHz equals ~13 inches full wavelength
2kHz = ~7 inches wavelength
5kHz - ~3 inches wavelength

Even if we assume that at least a 75% phase shift were required to have audible levels of attenuation, we're talking a "center" that's 3.25" wide at 1kHz, 1.75" wide at 2kHz, and .75" wide at 5kHz. All quite large enough to notice, though perhaps only on one ear at a time. Perhaps more important and evident would be that there will be just the opposite - coincident peak modes - just a half wavelength away for very definite apparent comb filtering at those frequencies.

I'm not saying that it wasn't a polarity issue, it apparently was. I'm just saying (I guess?) that we must have been given a incomplete description of the symptoms, because just a loss of bass wouldn't seem to indicate a polarity problem.

G.

Maybe i wasnt being as specific as possible, the speakers where outputing bass but where i sat and because of the phase of the polarity they just seemed to have cancelled each other out.
I cant do the scientific calculations but I could tell it didnt sound right then
P.S good speakers, sounding ace now!

[dementedchord]

Originally Posted by kubeek

60 volts peak into 4 ohm speakers is 450W (225W into 8ohm). Definitely not a home stereo.

The 9v battery, when you leave it connected for any longer than just sratching the terminals can produce cca 25W into 4ohm. That is more than enough to burn some voicecoils, because speakers are not designed for DC.

go look at some schemos of generic amps and get back to me... +/-60V is low for most amps...

[kubeek]

Originally Posted by dementedchord

go look at some schemos of generic amps and get back to me... +/-60V is low for most amps...

There is a big difference between rail voltage and possible swing of output.
You need to add some voltage drop over c-e due to high currents, rails sagging (a lot with small power supply caps and undersized transformers in cheap amps, and it is most obvious at very low frequencies), and balancing resistors and you end up at about 10 maybe 15 volts less under full load.

So a loaded "cheap ass stereo" will swing to cca +/- 45V. That is a lot more realistic, because you end up with 125W@8ohm and usually 1.5 times more at 4ohm and instead of theoretical double power, because of transformer current limitations.

I made a few amplifiers, including my 500W amp for bass guitar so I can say I know what they are capable of.