My friend and fellow ESL builder Richard, who also has an ESL web page, explains the polarity issue pretty well in this excerpt from his web site:
ESL Polarity
In a hybrid ESL, the panel and woofer polarities must match to play together, in phase. When out-of-phase, the woofer and panel sound waves combine destructively; resulting in reduced volume and a dip in the frequency response. Conversely, when the woofer and panel are in phase, their respective sound waves combine constructively, resulting in full volume and frequency response. This being so, we can use the resulting volume effects to audibly check the phasing.
To check the panel/woofer phasing in my speakers, I used a test tone matching the crossover frequency, and then determined correct phasing by swapping the (-/+) woofer connections and comparing the volumes, as described below.
With woofer and ESL panel on left and right channels of same amp, and crossover frequency set at 200Hz, correct phasing was determined as follows:
1) Downloaded 200Hz tone and imported it into Itunes.
2) With test tone playing and left channel (woofer) defeated, used
preamp volume control to set panel volume to normal listening
level. (preamp volume control to remain as set for remaining
steps)
3) With test tone playing and right channel (panel) defeated, and
using the gain control on the crossover, set woofer volume to
about the same level as the panel.
4) With test tone playing and both channels enabled, observed
their combined volume.
5) Swapped the [+/-] woofer connections to reverse phasing, then
To check the panel/woofer phasing in my speakers, I used a test tone matching the crossover frequency, and then determined correct phasing by swapping the (-/+) woofer connections and comparing the volumes, as described below.
With woofer and ESL panel on left and right channels of same amp, and crossover frequency set at 200Hz, correct phasing was determined as follows:
1) Downloaded 200Hz tone and imported it into Itunes.
2) With test tone playing and left channel (woofer) defeated, used
preamp volume control to set panel volume to normal listening
level. (preamp volume control to remain as set for remaining
steps)
3) With test tone playing and right channel (panel) defeated, and
using the gain control on the crossover, set woofer volume to
about the same level as the panel.
4) With test tone playing and both channels enabled, observed
their combined volume.
5) Swapped the [+/-] woofer connections to reverse phasing, then
compared the resulting volume to the previous volume.
After swapping the woofer connections the volume dropped
significantly, which indicated the panel and woofer were then
out-of-phase. Swapping the woofer connections a second time
restored the higher volume; indicating the panel and woofer were
then back in-phase.
6) Repeated steps 1-5 for the other speaker.
After swapping the woofer connections the volume dropped
significantly, which indicated the panel and woofer were then
out-of-phase. Swapping the woofer connections a second time
restored the higher volume; indicating the panel and woofer were
then back in-phase.
6) Repeated steps 1-5 for the other speaker.
