Recently i switched AVRs, went from Onkyo 646 to Denon x4700h, the results are mixed considering the price of Denon but oh well, life goes on.
In any case, everything was "fine" with Onkyo, didnt really notice anything out of the ordinary. Switched to Denon and when running Audyssey i noticed that the sub level was fluctuating kinda a lot (dont remember it being this way before). Onkyo is in service for 8 years, sub 2.5, and i tinkered a lot, my memory on how things were might not be correct.
So, the problem, on Audyssey SW lvl matching screen lets say the measurement is "centered" around 75 dB it will constantly jump up and down in a span of about 5 dB (72-77 constantly) and then it would go even further at times going down to 70 then back to 80. No clear pattern is observed but it looks like it does a big spike after a dip. It really isnt constant enough to draw conclusions. The spikes are easily felt next to being measured, the windows rattle just a bit when it happens.
Tried different cable, SW2 output on Denon, checked electrical socket with a checker, reports good ground and everything, ran SW signal from REW (thru Denon), unpacked old Onkyo and tried its level signal on SW. It is about the same, it fluctuates kinda a lot. I dont remember it being this way, sure sub will fluctuate the most during test signals but i remember it being around 1 dB for speakers and 3 dB for sub, dont remember sub dipping and spiking +- 10 dB. Watched some calibration process videos online and their subs are more in line with 3 dB fluctuation, didnt see any major spikes like mine.
Then i proceeded to do a near field measurement on the sub trying to avoid the room as much as possible and thats wheen i noticed theres a very slight hiss (rumble more exact) coming from the sub. Its doing so even without a signal cable plugged in. The rumble is present as long as the sub is active (its a SVS PB1000, it has standby) no matter the signal cable, when it hits standby the rumble stops. It is very low, i never noticed it before, you really have to put your ear to the cloth grille, 1 ft away and i cant hear it. Dont remember ever hearing it in 2.5 years with the sub. It doesnt react on volume at the back of the sub, cranked all the way up or down, the rumble stays the same level. The auto standby engages as expected, it isnt influenced by the rumble.
In normal conditions, music, movies, games, i dont really see an issue. Theres a slight out of place LFE explosion from time to time but that seems to be down to the rips/masters since they are reproducible exactly every time. When i hear something like that i rewind the scene couple of times to see if its constant and it always is.
Objectively, i cannot say when the "issue" started, it really isnt apparent in real content. Im not sure if the rumble (hiss) is connected to the spikes and dips during calibration or was it there since forever just not noticed. I do know that i did fumble a bit when changing AVR, i didnt turn off the sub on the hard switch before unplugging the signal cable on AVR side. AVR was on standby (electricity plugged in, video passthru not enabled, no ARC, CEC or anything, red LED). The sub was also plugged in but it might have been on active standby (blue led) or passive standby (red led), cant remember. It sure wasnt hard switched off and it was plugged in. When i pulled the RCA cable on AVR side there was a "pop" from the sub, not too loud but enough to startle me a bit. Sub volume was at ~45% on the dial.
Any help before i take the sub to service would be apreciated. I understand the hiss (rumble) is most likely down to electrical grid not being pristine but i didnt notice it before, neither have i noticed the dips/spikes, could it all be connected? Did i fry something with that cable fumble? There were no changes on electrical side of things, no breakers changed, outlets, etc.
TL;DR Sub fluctuates a lot during test tones, has a slight hiss even without signal cable that isnt influenced by the volume knob. Otherwise works "fine".
In any case, everything was "fine" with Onkyo, didnt really notice anything out of the ordinary. Switched to Denon and when running Audyssey i noticed that the sub level was fluctuating kinda a lot (dont remember it being this way before). Onkyo is in service for 8 years, sub 2.5, and i tinkered a lot, my memory on how things were might not be correct.
So, the problem, on Audyssey SW lvl matching screen lets say the measurement is "centered" around 75 dB it will constantly jump up and down in a span of about 5 dB (72-77 constantly) and then it would go even further at times going down to 70 then back to 80. No clear pattern is observed but it looks like it does a big spike after a dip. It really isnt constant enough to draw conclusions. The spikes are easily felt next to being measured, the windows rattle just a bit when it happens.
Tried different cable, SW2 output on Denon, checked electrical socket with a checker, reports good ground and everything, ran SW signal from REW (thru Denon), unpacked old Onkyo and tried its level signal on SW. It is about the same, it fluctuates kinda a lot. I dont remember it being this way, sure sub will fluctuate the most during test signals but i remember it being around 1 dB for speakers and 3 dB for sub, dont remember sub dipping and spiking +- 10 dB. Watched some calibration process videos online and their subs are more in line with 3 dB fluctuation, didnt see any major spikes like mine.
Then i proceeded to do a near field measurement on the sub trying to avoid the room as much as possible and thats wheen i noticed theres a very slight hiss (rumble more exact) coming from the sub. Its doing so even without a signal cable plugged in. The rumble is present as long as the sub is active (its a SVS PB1000, it has standby) no matter the signal cable, when it hits standby the rumble stops. It is very low, i never noticed it before, you really have to put your ear to the cloth grille, 1 ft away and i cant hear it. Dont remember ever hearing it in 2.5 years with the sub. It doesnt react on volume at the back of the sub, cranked all the way up or down, the rumble stays the same level. The auto standby engages as expected, it isnt influenced by the rumble.
In normal conditions, music, movies, games, i dont really see an issue. Theres a slight out of place LFE explosion from time to time but that seems to be down to the rips/masters since they are reproducible exactly every time. When i hear something like that i rewind the scene couple of times to see if its constant and it always is.
Objectively, i cannot say when the "issue" started, it really isnt apparent in real content. Im not sure if the rumble (hiss) is connected to the spikes and dips during calibration or was it there since forever just not noticed. I do know that i did fumble a bit when changing AVR, i didnt turn off the sub on the hard switch before unplugging the signal cable on AVR side. AVR was on standby (electricity plugged in, video passthru not enabled, no ARC, CEC or anything, red LED). The sub was also plugged in but it might have been on active standby (blue led) or passive standby (red led), cant remember. It sure wasnt hard switched off and it was plugged in. When i pulled the RCA cable on AVR side there was a "pop" from the sub, not too loud but enough to startle me a bit. Sub volume was at ~45% on the dial.
Any help before i take the sub to service would be apreciated. I understand the hiss (rumble) is most likely down to electrical grid not being pristine but i didnt notice it before, neither have i noticed the dips/spikes, could it all be connected? Did i fry something with that cable fumble? There were no changes on electrical side of things, no breakers changed, outlets, etc.
TL;DR Sub fluctuates a lot during test tones, has a slight hiss even without signal cable that isnt influenced by the volume knob. Otherwise works "fine".
Last edited: