3 way active system "hole in a center" imaging problem ... help

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Hi members

Finally thanks for those who helped out for my 3way speaker height placement problem.

I have another problem to look into now ... having problem of imaging problem "hole in the center" issue. The chair is my listening position. My listening position seems having destructive interference problem. in other words the sound at the listening position is subdued. If i only listen to one of the speakers either the left ones they sounded much better. My previous speakers which were 2ways close to the monitor always provide better imaging due to they sit much closer to the monitor.

I've readed about ESP's stereo width controller ... where the author states this might happen if the speaker were placed either too far or close apart. Mine to the left and right is 2.5feet and 2feet facing the monitor. speakers were placed in a toe in manner facing my listening area. tweeter height was corrected to ear level as suggested

Now i am facing problem that i cannot place the speakers closer due to space limitations (desk is very long).

please help ... opinions and suggestions appreciated ...
 

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Hi,
Your desk may create ugly reflections(and thus comb filtering) in the a 1,5k/4k range. If your loudspeakers doesn't face the same conditions for loading it may play a role too.
But from my experience a 'hole' in the center image is a symptom of one of your mid with inverted polarity.
I would check connections first.
 
Make the surfaces surrounding the speakers and affecting the reflections symmetrical. One speaker is next to a wall while the other speaker has a PC next to it, that's not symmetrical. Imaging depends on timing and phase of high frequencies, they have short wavelength and therefore very vulnerable to reflections. Reflections from the wall and the PC are too close in time to the direct sound from the speakers, which ruins the directional cues.

Try putting the PC down on the floor to get it away from the high freq drivers. If there is no wall next to the right speaker, then you have to kill the wall reflection of the left speaker with absorption panel to make it symmetrical.
Good luck
 
No 1 check the Polarity.
No 2 recheck the polarity
If you are worried about the corner loading then temporarily relocate the speakers to check.
If anything has reversed the phase on any of the drivers then you will never get it to sound right! Don't waste your's or anybody else's time until you are sure they are correct.:)
 
About 10 years ago, I bought a mint Sony/MCA broadcasting console from a closing studio for almost nothing. The studio owner said the console sounds horrible and no one wants to use it for more than 10 years. Well, I found that it was because about a half of the patch bay polarity (hot and cold) was wrongly connected.

Check polarity first. :)
 
Put the speakers right next to each other. Connect one amp channel to both speakers in parallel.
Play something at a nice level for your face a foot away from the drivers dead center.
Head at woof level, you should hear the bass dead nuts between the drivers. Repeat with mids and highs.

If all center exactly, relative polarity is correct, if not you know where to look.

Jn
Ah, just noticed active. Play a mono signal then. Balance is not a real problem, adjust levels for a centered image.
 
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:up:

Nice you identified and solved the issue!
I must say not everybody does identify that kind of phase issue, i ve heard system in so called 'professional' environnement which had same problem and nobody seems to care about (experience more or less similar from Plasnu's example).
The comment from Xoc1 should not be taken as harsh sounding cause for professional (he is one) it is very obvious that this kind of issue come 99% from miswiring.
This is much less obvious for someone with less experience.
Anyway now you experienced it you'll recognise it each time you'll encounter. It drive me crazy when i am at a liveact ( it happen more often than never...) and experience this, it's difficult to explain the engineer you identified a problem which he have not...
 
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"Wrong polarity" in one driver of a 2-or 3-way speaker is not always easy to solve. One should measure each speaker's response and check impulse/step. It depends on crossover, which way is the intended polarity - it might be reversed, usually the mid in a 3-way!

I am familiar with this issue too! I have "corrected" some speaker wirings before I understood the complexity...
 
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ya it is my first biggest venture into triamp sytem ... previously was on biamp system till i get bored finally gave in to try something new ... but being lazy due to the need for building the enclouse ... so happen to have a friend of mine want to scrap this pair of speaker due to their original drivers were damaged and internal passive crossover were burned ... at the plus side of no need to build an enclosure from scratch but i still have to enlarge the hole for my new midrange and recut terminals for active 3 ways ...

FYI these drivers were not the original ones for these enclosure ...

Below the photos can be seen from the first to the last one ... the original drivers ... terminal add on for triamping (below is the original terminal) ... cutouts modified for new drivers ... modified system
 

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