Multi-Subs Not Moving in Sync with Each Other

[audioholic 5,000+ posts]

Me get over it? You seem to be forgetting who keeps bringing it back up.

 

[DDDD 10+ year member]

Technically if you have a 6th order low pass filter with 8 subs you have 11 inductors, 8 of which create extremely strong magnetic fields. With the 8 subs even the slightest tolerances in impedance (+/- 5%) could yield slight phase shifts that would be exacerbated by the extremely strong magnetic fields setup by each driver within close proximity.

That, or there's some much simpler explanation.

 

[james33440 10+ year member]

Technically if you have a 6th order low pass filter with 8 subs you have 11 inductors, 8 of which create extremely strong magnetic fields. With the 8 subs even the slightest tolerances in impedance (+/- 5%) could yield slight phase shifts that would be exacerbated by the extremely strong magnetic fields setup by each driver within close proximity.
That, or there's some much simpler explanation.

So, let's assume that this technical answer is the reason for the appearance of different excursions. Would this result in any harm to the subs?

 

[Berry47 10+ year member]

Have you ever thought that it might be your eyes????

 

[helotaxi 5,000+ posts]

Technically if you have a 6th order low pass filter with 8 subs you have 11 inductors, 8 of which create extremely strong magnetic fields. With the 8 subs even the slightest tolerances in impedance (+/- 5%) could yield slight phase shifts that would be exacerbated by the extremely strong magnetic fields setup by each driver within close proximity.
That, or there's some much simpler explanation.

IF you are using a 6th order passive filter with a large bank of subs then you are a moron. Also, who uses a 48 dB per octave passive filter? Nice try at wowing the folks but, no.

The nice thing about series/parallel wiring combinations is that the coils of the subs tend to cancel out each others slight irregularities. Also, I cannot imagine a voice-coil getting through any type of QC process with a 5% deviation from the desired spec. That much of a difference in Le would totally wreck the T/S parameters of the sub. Next, crosstalk between two speakers in close proximity is not a factor. The magnet assembly of the speakers sees to that. You may get a distortion of the field of the fixed magnet assemblies but it should not have much of an effect on the field in the voicecoil gap and should not affect the field generated by the coil.

The best explanation is illusion. If it was a phasing problem, you probably would have over-stroked the two out of phase by now and blown them because they would effectively be unloaded and the enclosure would be horribly oversized and mistuned as well.

 

[DFW40 10+ year member]

I found this on the JL tutorial site:

Also, could a voicecoil be blown?

"Please note that when wiring multiple drivers, whether DVC drivers or their SVC brethren, it is recommended that series connections between drivers be avoided at all costs. This does not include series connections made between voice coils on the same driver. "