SDA bandwidth on 1B
Schurkey
Posts: 2,104
Should the 1B have any SDA-signal that produces music at the tweeters?
I thought that the SDA effect was bandwidth-limited to the midwoofers and NOT also the tweeters on the 1B; and I can stare at the 1B schematic all day long and not understand how SDA signal is getting to my tweeters. I expected DEAD SILENCE from the tweeters even though the SDA signal drives the midwoofers.
Results are the same no matter which speaker I disconnect the + cable from. That speaker will have active mid-woofers and tweeters when powered by ONLY the SDA cable. Of course, the volume is pretty low in comparison to the other speaker, as its only the SDA-Reverse Phase-Voodoo signal.
I did not perform this test before re-working the crossovers; so I don't know how "stock" 1Bs would react to having one + speaker cable disconnected. My concern is that perhaps I soldered a capacitor or resistor out-of-position--or--there was an existing defect in my crossovers that I did not fix when I re-capped them.
I've always thought the treble on my 1Bs was lacking; Lord knows I've had other various and sundry problems with the speakers over the years. At this point--I think they sound at LEAST "as good", if not better than ever before. Even so, if there is out-of-phase SDA signal improperly getting to the tweeters, one result would be to cancel out some of the music signal and reduce the treble volume.
Test Conditions: Speakers connected properly to the common-ground amplifier and to each other by the OEM blade/blade cable. Play music. Remove either (but not both at the same time) + speaker cable. The speaker without a + signal is then driven by ONLY the SDA cable; and the circuit back to the amp is completed through the - speaker cable.
I thought that the SDA effect was bandwidth-limited to the midwoofers and NOT also the tweeters on the 1B; and I can stare at the 1B schematic all day long and not understand how SDA signal is getting to my tweeters. I expected DEAD SILENCE from the tweeters even though the SDA signal drives the midwoofers.
Results are the same no matter which speaker I disconnect the + cable from. That speaker will have active mid-woofers and tweeters when powered by ONLY the SDA cable. Of course, the volume is pretty low in comparison to the other speaker, as its only the SDA-Reverse Phase-Voodoo signal.
I did not perform this test before re-working the crossovers; so I don't know how "stock" 1Bs would react to having one + speaker cable disconnected. My concern is that perhaps I soldered a capacitor or resistor out-of-position--or--there was an existing defect in my crossovers that I did not fix when I re-capped them.
I've always thought the treble on my 1Bs was lacking; Lord knows I've had other various and sundry problems with the speakers over the years. At this point--I think they sound at LEAST "as good", if not better than ever before. Even so, if there is out-of-phase SDA signal improperly getting to the tweeters, one result would be to cancel out some of the music signal and reduce the treble volume.