ok, here we go again. I've read through quite a few other posts on this topic but couldn't quite find what I was looking for.

Receiver is about a 10 year old Nakamichi AV300. Has a single RCA output for the sub.

For about the first 5 or 6 years I had it, everything was fine. Then the subwoofer (plugged in via RCA to the LFE output) started popping when the receiver was turned on or off (sub was set to auto function).

Changed to a different sub, same noise. Changed RCA cable, same noise. Changed to the speaker level connection on the sub (Receiver>Sub>Mains) and the pop is gone.

I'm guessing the noise is probably the result of some ground fault somewhere in the receiver and the LFE output. Who knows how much to fix - probably not worth it considering the age of the receiver.

Anybody have an educated guess if this is damaging to the sub at all? The pop does seem related to receiver volume, so I try to remember to turn it down all the way before powering on/off. I've seen a few posts indicating that some subwoofer popping is normal - if it is that's fine, but obviously something is weird here because it didn't always happen.

rmp

Or you could just keep the sub off until after you've turned your receiver on. Turn on the receiver and then the sub.

My recently retired Mirage BPS 400 (good piece) has been popping for ten years in the middle of movies when called to action. Irritating? Yes. Devastating? No.

Have you changed your main speakers in the last 4 years that you didn't post this problem? The pop may have been there the whole time and you couldn't hear it.

Sub pop is common and you didn't tell us what sub you have.

I have two subs right now - neither one is very expensive, but when I last tried LFE, the popping effect (louder when powering off?) was the same with both.

A very old Yamaha YST 150 (with some mid 90's JBL 3-ways) and a newer Polk Audio (little puny 50W 8" number that came with a HTIB-ish setup). I was running the Yamaha when the problem first started. Had to temporarily use the polks after we moved, but those are long gone. I used the Yamaha sub with this setup for 3-4 years without issue, then all of a sudden the popping appeared.

I've been running the speaker level wiring scheme on the sub for a couple of years now, but with my new NHT M5 speakers (L,C,R) I'm seriously considering purchase of a new sub to match them (Hsu STF-2 or similar). New sub has to go in the back of the room, and it will be much easier to run a single coax back to it (from the LFE) than an out and back speaker wire run.

I have not tried the LFE output since my new speakers arrived.

This isn't a huge deal, but if bugs me enough to try chasing it down. The Nakamichi receiver will be replaced within the next year (for one with HDMI capability) but otherwise seems to work perfectly.

Hooked the sub back up via RCA/LFE last night. If the receiver is already on and I turn the sub on, it doesn't pop. If I turn the sub off (unplug it) - no popping.

When it does pop: switching audio modes on the receiver, and powering off the receiver. Even with receiver volume turned all the way down, pop is still there, same intensity. When powering on the receiver, the pop is much quieter.

rmp