Re: Speaker imaging problem - Out of Phase ?? - Franco

Speaker Asylum

General speaker questions for audio and home theater.

Re: Speaker imaging problem - Out of Phase ??

In Reply to: Re: Speaker imaging problem/me too posted by Susan on January 31, 2001 at 08:33:51:

Hi,
It seems me possible you have some out of phase on the loudspeakers.
Pay attention to the operations taking care of any risk of damage of equipment or shock hazard, thus made any operation switching off the power to the system BEFORE to made any attempt to operate on the loudpspeaker cables; switch on the system only AFTER you have securely fastened the connections to the terminals and everithing is made safe as original ... Otherwise do nothing!! ask for expert personnel!!
Check the connection betwen the amplifier exit terminals and the speakers input terminals; red and black termination or + and - sign identify the amplifier exit polarity, check that the red (or +) pole is connected to the red (or +) terminal on each loudspeaker, the black (or -) should be connected, obviously to the other couple of terminals.
Note if you are bi or tri-wired (you will have two or three separate couples of terminal on loudspeakers each one having a separate cable running to the amplifier terminals) check the polarity of each connection with the same rule.
If it is all right check the soundstage now, probably your problem is solved.
Otherwise it is possible to suspect that inside one of the loudspeakers there is a reversed connection on a driver.
To check if the woofer are in phase simply connect a 1,5 Volt battery (respecting the polarity from battery to cable and loudspeaker terminal ++ / --) to the loudspeaker cable on one cabinet (disconnected from the amplifier side).
When connect the battery look to the woofer cone, it will move in one direction (normally toward the room and not toward the box); make the test on the other loudspeaker respecting the same polarities and look if the cone move in the same direction, if it is true the woofer are in phase otherwise the cabinet wiring to the woofer with the wrong cone movement (toward the box) should be reversed into the cabinet at the woofer driver connections or on the cable exit from the crossover circuit.
After the test you will have the amplifier to loudspeaker cables the woofers in phase, thus the mid-bass area should have a sound rich and complete, it may remain problem on mid-treble area, most important for the formation of the stereo imagin.
Tweeter or midrange on three way systems cannot tested in the same way as woofer!.
The test can be made only with a mono source (i.e. My disc from Sheffield lab has good testing tracks for this purpose as some Chesky) otherwise use the signal from a tuner switched in mono. Inspect the system in the following way:
Move the balance fully in one direction and accurately listen the sound, then quicly and fully rotate it in the opposite direction checking if there is an audible difference between the righ and left speakers sound.
The loudspeaker having the best tonal balance and full sound will be your reference.
Switch off the system and on the other loudspeaker (the worst sounding) reverse the wires on the tweeter driver after having unscrew it from the cabinet (may be difficult on some arrangement, I cant help on this!); reassembly the tweeter on the cabinet and repeat the previous test; is it everything okay ?
If you have a tree way system the same test and polarity reversal may be necessary to be made also on midrange BEFORE to test the tweeter.
Now moving the balance from left to right and vice versa the sound should be the same otherwise:
A driver may be damaged
A crossover may be damaged
A component of the amplification chain may need some fix.
If something is not clear or you have doubt send me separate email, I will try to give you more help!
Bye
Franco

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Follow Ups Full Thread

Topic - Speaker imaging problem..help. - kclck 18:11:17 01/30/01 (5)

Re: Speaker imaging problem..help. - RBP 18:41:03 01/30/01 (4)

Re: Speaker imaging problem/me too - Susan 08:33:51 01/31/01 (3)

to the post-er that emailed me earlier today...please re-email your suggestions... - Susan 18:47:18 01/31/01 (0)

Re: Speaker imaging problem - Out of Phase ?? - Franco 01/31/0118:25:33 01/31/01 (1)

Re: Speaker imaging problem - Out of Phase ?? - Susan 18:43:41 01/31/01 (0)

Follow Ups

Re: Speaker imaging problem - Out of Phase ?? - Franco 01/31/0118:25:33 01/31/01 (1)

Re: Speaker imaging problem - Out of Phase ?? - Susan 18:43:41 01/31/01 (0)

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