4430/4435 Phase problems

[leif]

A while ago I had an audiophie friend over. He litstened to my system, and after a while he said that he think it is not playing in phase. We swithced cables on one of the speakers. And it was actually hard to hear if there were a difference. That should not be so, right? When I set up my 4 pa speakers earlier this year, they were wrong connected, and that was very obvious from the very first second of listening.
I mentioned this to Baldrick, that used to own a pair of 4435, and he said the same phenomene happend in his home. How come this happens? It should be very very very easy to hear if they were out of phase, right? Like there were almost no bass... When I switch, I can not say if it is right or wrong actually. Any ideas?

Leif

[Thom]

Did you do your test in mono? Presuming that you only have two channels, do you have an apparent center channel hooked either way?

[Robh3606]

4430/4435 Phase problems

That seems odd have you tried using a Phase track on a stereo set-up disk?? You may want to try another pair of speakers to see what's up.

Rob

[Andyoz]

Do you get the same effect if you move the speakers to another location in the room?

[grumpy]

... It should be very very very easy to hear if they were out of phase, right? Like there were almost no bass... When I switch, I can not say if it is right or wrong actually. Any ideas?
Leif

Hi Leif,

The bass cancellation should be more pronounced if you put them next to each other.

Using a mono signal (FM interstation noise works), there should be a place you can sit
with the horns at ear level that the "image" will collapse to a midpoint between the
speakers when they are in-phase, and sound "phasey" when out of phase (sometimes
sounding like beyond the space between the speakers). If this isn't fairly obvious in sound,
perhaps the units are mis-wired (one horn or one bass driver) making it impossible to
get the units in-phase.

I can try this at home (with 4430's -specifically-) later today to verify what I've done
with many other systems...

-grumpy

[toddalin]

Maybe its not the bass that's out of phase. Maybe it's the horn.

The phasing of the horn can be somewhat ambiguitous. When I phase my horns, I look at the greater increase in overall volume near the crossover point. But regardless of how I wire the horns, some frequencies are quieter one way than the other. That is, even when the horns are wired to produce the greater overall volume, some frequencies are still quietier than when the horn is wired the opposite way. Maybe your friend is sensitive to this.

[grumpy]

OK... did the in-phase/out-of-phase comparison using 4430's using
FM noise in mono and switching the speaker leads at the rear of one
speaker, then back.

While not as day/night as when doing this using a test CD (transition is
much quicker, and your head doesn't move much), and perhaps not
as obvious as other speaker systems, the effect is still quite noticeable.

When in phase, I noticed that changing the listening position (side to side
slightly) just made the image shift from center to the closer speaker.
When out of phase, the image shifted back and forth several times as I
moved my head from one side of "nominal" to the other,
as well as simply being not as centered as the in-phase case... the sound
appeared to be coming from two speakers, not from a phantom image.
I hope this description helps somewhat.

I currently have the 4430's and listening position set up as a roughly 12'
(4m) equilateral triangle, with some toe-in of each speaker.

-grumpy

[leif]

I pulled the speakers so they were standing side by side one inch from each other. The bass was still there, and I changed the cables on one of the terminals on the amp, and the bass dissappeared.
So why it dont happen that way when they are standing in normal listening position is a mystery to me.
Room problems? The room is large with large walls without too much on them to damp reflections. And also a large wooden floor that is vibrating when playing loud is probably also some of the reason... I dunno.

[Mr. Widget]

I pulled the speakers so they were standing side by side one inch from each other. The bass was still there, and I changed the cables on one of the terminals on the amp, and the bass dissappeared.

As it should do...

So why it dont happen that way when they are standing in normal listening position is a mystery to me.
Room problems? .

Problem may be the wrong word... bad speaker/listening position is likely your concern. You will need to experiment with placement.


Widget

[Ian Mackenzie]

You might want to check the internal phase continuity of the compression driver. As I recall all drivers should be wired in phase with these systems.

Typically, with a precisely symmetrical loudspeaker positions and some toe in "the image" on a loudspeaker phase test cd will sound like the voices coming off the walls out of phase and holographic in the centre in phase.

Some Pink Floyd is actually recorded out of phase and you get the same effect. The reason its so pronounced is the good power response on the horn.