Sub Not auto activating

xandra

PROBLEM:
1. Sub sometimes - particularly/only? with 2 channel sources (dd2, stereo) &/or sources without an LFE specific channel, rarely activates. Sometimes it does but only after several minutes.

I Often need to play a moment or 2 of something with .1 track, or with super strong bass to get it going.
Once on, the sub seems to function properly (I can feel vibration on rubber surround - on the same source that failed to activate it initially).

Have tested with 2 different subwoofer cables (Monoprice 6', Signal 12') - this had no effect. Source component doesn't matter.

SPECS & SETUP should they matter.
This is with a Denon 3808ci AVR with a KEF PSW 2500 sub.
Denon settings-
Crossover set to 80Hz (including the 2 channel specific setting)
Sub is set to LFE & Main, 120Hz.
KEF: powered downfiring sub, with slope setting to 24, 50% volume, Phase at 0.

RELEVANT???
I tend to keep denon's gain setting for sub channel pretty low by most peoples standard.
I have my seperate Amp set trigger by audio signal (rather than 12 volt, to avoid spike) so often, sound doesn't come on till a second or so after playing begins.
further, I have Amp set to filter out stuff below 20Hz (to protect speakers while playing unprocessed analog input)



Equally concerning: It Seems like speakers still continue to play these low frequencies... (thus duplicating sub output - UGH)

tugboat

I ran into the samething with my PSW650. I would have to up the volume or wait for a loud bass passage for it to turn on, but then it would turn off after a few minutes once the volume was turned back down. To fix the problem, I set it in my Denon to run about 8db hotter than it needed to be, but then used the volume dial on the sub itself to set the proper db level. Now the sub gets a stronger signal from the sub output of the Denon and kicks on amost immediately and stays on as it should.

Might be worth a try on your end.

dubradio

Xandra,

The Auto turn-on function on many subwoofers require a certain voltage to be seen to click into action. Many times if the sub pre-out is being used with 2 channel sources the voltage becomes dependent on the volume of the reciever. So at lower volumes the voltage is lower and the sub still thinks there is no signal. This becomes especially problematic in recievers where you are running your front speakers as "Large" .

xandra

BINGO -- You're both right. That worked.
Now I just need to fiddle with things to get desired balance. (+ next time I run Audysses - I'll probably set sub to about 1/4 gain instead of 1/2 and have IT do the work)
Oh well, Seems the rest of the world likes louder and bassier

THANK YOU, THANK YOU

What a great forum.