Originally Posted by notpierce
have a few qs about my fairly recently acquired Rythmik LV12R sub which i was hoping y'all could help me with.
1) played "war of the worlds" scene (where the aliens come out of the ground) to try out the sub & saw the led light at the back of the Rythmik LV12R subwoofer blinking few times. the subwoofer gain was at 5 notches above 12 o'clock (approx 1 o'clock) & the avr's volume at around 14 (have run audyssey with the sub at 12 o'clock which returned a trim for the sub of -5). playing around with the gain and avr volume find that the blinking in that scene starts occuring at about 3 notches above 12 o'clock & avr volume at 15+. if i turned down the gain/avr volume a little then it only blinked once (when the first ray is shot). I've read here that it's a sign of the limiter kicking in, but what does that mean? that the sub could get damaged? should i turn down the gain? what are the possible effects of keeping the gain at such a level that it clips occasionally as such demanding scenes are few.
2) in my setup i found that there's a big difference in the sub being at 12 o'clock where it sounds ok but like a regular sub & at say 2 o'clock where you really feel & enjoy it. is that ok or indicative of any issue? would it be ok to keep it at 2 o'clock if there is no audible distortion?
3) is it ok to flip the Bass extension switch/LPF slope setting while the sub is on & media is playing?
4) sometimes when i skip scenes in a movie there is a slight pop sound from the sub. i also have a klipsch rw12 sub connected & there is no such pop from it. what could that be due to?
5) in one of the pleasant (& unexpected) effects of having the LV12 - the aforementioned klipsch sub before the rythmik came in would rumble & make some creaking sounds in demanding scenes but now when i have both the subs on the klipsch has stopped making those noises. how does the rythmik stop another sub from doing that?
6) is it better to run audyssey with just the LV12R running or both subs on?
7) if i read the quick guide right, for movies Bass extension switch should be LOW & LPF to 12db & for music it should be HIGH-24db? so for what media should the Bass extension switch be on MID?
1) limiter kicks in when the sub is expected to play louder than it can and that is based on the combined effect of the master volume, sw level in AVR, and sub gain knob position. The conventional advice is to set the sw level in AVR at -6dB or lower after adding whatever boost you want and they add more via gain knob if necessary.
(However, you would want to start with a sub gain knob position that results in Audyssey setting the sub level around -10dB to -11dB or so, to allow you to turn up the sw level without exceeding -6dB or so. Then add via gain knob if you need more bass.)
Of course, because the sub can only play so loud, especially the smallest ported Rythmik, scenes with strong bass especially under 30Hz can trip the limiter if you are adding too much bass boost and/or simply have master volume too high. I would find a balance of MV, sw level and gain knob that results in the limiter not engaging at all or only slightly on the most demanding scenes. That will help protect the sub from amp clipping and driver over-excursion.
Brian has mentioned turning things down even just 1-2dB can stop the limiter from kicking in.
2) This is normal, especially with well designed subs like Rythmiks... they only draw attention to themselves when needed. If you want to know the sub is playing at all times you will likely be running things quite hot (ample bass boost).
However, you should respect the limits of the sub (or get more/bigger subs and/or more optimal placement, integration, EQ, etc.)
That means limiter should rarely if ever kick in and the sub amp should not get hot to the touch during long, intense listening sessions. You want to make sure that there is some headroom above your listening levels so that the sub is not constantly being pushed to its limits or beyond.
3) I would switch off the sub before adjusting LPF slope otherwise a loud pop occurs. Adjusting Bass Extension/Damping can be done with sub on, but I would pause or mute audio to be safe. I think if using Line In, crossover knob at max and 12dB LPF slope should be ideal for music and movies. Mid bass extension/damping on the LV12R is the best compromise IMO. High gives up too extension and Low is too boomy for best music SQ to me.
For the rest)
Running duals (properly gain matched and time/polarity aligned) will put less stress on each sub vs. single sub... however, I would use 2 of the same sub for best results and run both through Audyssey.