Blues

I want to check whether my front speakers are in phase but don't want the hassle of removing the door cards. It's a MY00 turbo wagon and unless I'm missing something obvious there seems no easy way to check. Can you tell just by listening as I get a 'slightly louder' volume when I switch one set of cables. Maybe my imagination tho ... 5 1/4 Kennys are in the door going to a Rockford 2 chn amp.

Hope all that kinda made some sense,

Blues.

nom

Put something on with loads of bass (turn the bass up too if unclear when checked), turn up to a reasonable volume & then play left (or right) only followed by both channels, preferably with your head between the two seats (makes it easier to tell). There should be relatively more bass with both driven than just one. Much easier to tell with mono sound than stereo, if you can get hold of a mono recording somehow...
If they are out of phase it should be pretty obvious.

TBMeech

You could turn it up until the speakers distort, if one distorts faster than the other then you know there is a problem, are your gain settings on the amp at the same level?

Blues

Ta for the replys.

The gain settings on the amp are a equal as I can get. Installed on the back of the back seat facing down so not too easy to adjust or see what its set on !!! Just a bit unhappy to unscrew from the seat at the mo but it may come to that. Not too happy with the install to be fair ... get the feeling I could have done better and that some statement for me to make !

So if I get it right there should be more bass playing when in phase?

What I tend to do tho is run them on a -3 to -4 bass level so in that case does it matter about phasing???

Confused now.

Blues.

TBMeech

Ok, have you got the amp running full range or hi pass?

If i am not mistaken (dont hold me to that!) phasing is usually between 0 and 180, it tends to only be used for subs, as sometimes they come out of 'phase' when running them, i would imagine what's happening is you got one speaker thats louder than the other, if thats the case dont forget the amp is more efficeint than a head unit, so will sound louder, it will sound louder on the drivers side to you as the speaker is closer to your ear than say the passenger side, i would personally test the distortion, then check the gain, if you got a Rocky punch amp the gain controls are a mare as you need a teeny screwdriver to adjust them, plus there are no markings

Blues

Cheers for the ideas. May have to wait 4 the weekend to have a bit of a play arounf in the daylight. I also don't like doing this sort of thing at home or work where people can see / hear what you have.

Will post when I have more info.

Blues.

globbits

Blues

If you can see the speaker cones, then you're in luck. Disconnect the wires from the amp. Get someone to watch one of the cones, while you connect an AA battery across the wires for the speaker, +'ve to +'ve, -'ve to -'ve. Make a note of which way the cone moves.

Do the same for the other speaker. If the cones don't move the same way, one of them is phased backwards

Oh, and if they don't move at all, try a bigger battery. You can use a 9V PP3 battery, but only touch it onto the terminals quickly - long application of the DC current will damage the speaker.

Happy phasing!

stevencotton

Is that safe? I'd have thought any amount of DC wouldn't do any speaker any good, same as an amp that's clipping isn't it?

Steve.

nom

Sort of like clipping... well, like it enough in the 'bad' way.

It should be easy enough to tell with just listening. The phase change would only be 180 degrees here which makes it easier, and it does make a difference to the whole frequency response - it's just easiest to tell with the bass as it's the most obvious cancelation (bass waves are bigger!). I'd adjust the frequency response to flat or even extra bass, just to check, then turn it back to where it usually is afterwards.
Why is it so low? Is this preference, or 'cos there's distortion? I just ask as it's unusual to run with bass negative!

Blues

I run the bass low mainly to stop disportion at higher levels. Not too sure I've ended up with the best speakers (dealer recommended) as my old Rockys were soooo much better with the bass. Larger size obviously helped (6 1/2 to 5 1/4). Vocals are fine tho and I get enough bass from the sub not to worry about it too much. I didn't fancy fitting them myself and don't want the hassle / expense of changing now. You live and learn ...

Blues.

nom

Sub? Ah, OK, extra complication: disconnect the sub while checking the phase. If you hadn't already! Sub should be the last thing to set up, as frequently amps have the polarity wrong on the sub-out anyway (either that or the speaker is). Anyway, last!

driver

If the right and left fronts are wired out of phase relative to each other, adjusting the balance control to the right or left speaker only will increase the bass output. One side should be rewored to fix this. Put in a bass heavy disc and try it. If however the bass level drops when you move to the right or left, the speakers are correctly wired.

If you are not getting enough bass output from the fronts, you may wish to check the seals (gaskets) around the frames of the speakers. If you have large openings there, that can cause cancellation and reduce the bass output. Output from the backside of the speaker is 180 degrees out of phase with the output from the frontside of the speaker. When the 2 outputs meet, you get a reduction in bass.

If you are highpassing the front signal via a crossover in the amplifier or headunit (HU), you may have it set too high. Try lowering it until you get more bass output but not so much that you bottom or distort the speaker output when playing heavy bass like techno.

Lastly, if you are using a subwoofer, try reversing the + & - connections from the amplifier to it. This may increase your bass output as now the subwoofer is acoustically in phase with the fronts vs. electrically in phase.

Good luck!

driver

[Edited by driver - 1/27/2002 3:44:58 PM]

kryten

Of course 'in phase' may not equal 'sounds best'.

Unless you have a Mclaren F1, the path length differences will add complications. I've often found it beneficial to put one of the mids out of phase!

The only way to do it is to listen and make notes (on some bits of music you know well). Then reverse phase to one speaker and listen again. Keep going until you run out of speakers.

Then do it again but with the sub connected and then reverse connections to the sub.

An RTA may help, but you'll still need to listen. No one else can tell you what sounds best to YOUR ears!!

Adam M

I completely agree with kryten.

I dont understand everyones desire with phasing to make sure all is ok. The only difference here is the shape of the soundfield caused by the intereference of two sound sources ( the mids in this case) the frequency of the tweeters is too high the changes in the sound field to be detectable by movement of our heads.

The acoustics of the car are so terrible that reflections and vibrations are going to destroy the point source model, and so the only way you will know what is better again as kryten says is to listen and see what you prefer. Its only going to shift the field in space and you may find your ears sit in a sweet spot now whereas they didnt before the change. In the process your passengers may hate the change.

Make sure you decide who you are setting it up for and listen to the changes from the seat they sit in, which I hope would be the drivers seat!

nom

I'm not sure that the mids/woofers should be out of phase though - the tweeters, yes, but I think I've only ever heard one 'car' when there was a different phase for one pair to the next (and that was front/rear) for woofers. Subs are different 'cos of being in a different chamber, though. Tweeters are different as, well, the frequency they handle...