Lfe or lfe main denon x2500 and powered sub?


Active Member
I’m not quite getting what I need to have my system set to for sub channel

At the moment, I have small front 3 channels and 2 rears and a powered sub and a denon x2500h receiver.

My audio settings on the amp are to not do anything with any input that the receivers picks up as 5.1, but if it detects dolby 2.0 or pcm, it will apply Dolby surround to this signal, this way I am always getting sound via the centre speaker as the difference going from Dolby 2.0 in stereo to 5.1 using centre is apparent.

Problem is, when running Dolby 2.0 or pcm material, there never seems to be enough low end signal to kick the subwoofer in, or there is a bit, and then it go’s off, then comes back on again so I hear the sub switching on and off.

My sub setting is set to ‘LFE only’ on the receiver, should I set it to ‘LFE and Main’, and if so, will this affect the Dolby 5.1 signals I receive and mess up the discrete lfe signal on 5.1 material?


It could mess it up and cause boomy bass because you will be getting a bass signal from both sub and connected speaker. There is an option on the audio buttons for stereo that will employ the sub.
Stereo music is a weak point of most AVRs. Depending on the size, physical size, you could try Pure Direct and listen to how the speakers perform.

Switching the sound mode​

Press MOVIE, MUSIC or GAME to display a list of the sound modes that can be selected. Each time you press MOVIE, MUSIC or GAME, the sound mode changes.
While the list is displayed, you can also use
to select a sound mode.
Try out various sound modes and enjoy sound mode in your favorite mode.
Bracket Open
Bracket Close
When MOVIE is pressed
GUI Surround X2200


Active Member
Thanks, it’s those movie options I’m using to convert Dolby and pcm to Dolby surround. If I keep the 2 channel stuff as stereo then everything including voice etc comes out of the left and right speakers, which is a pain when you then switch to a different channel with 5.1 signal and all the speakers work properly.


Active Member
just been reading another thread where someone had a similar issue with different hardware, and they had improvements by increasing the sub level in the av receiver and then lowering the actual level dial on the sub itself - in essence feeding the sub more signal.

Also read that some people don't activate the 'auto off' feature on their subs as sometimes either.


I'm a little lost as to what you want to achieve. Do you want the stereo, music I presume, to be played as intended but with the sub picking up the bass duties. Or do you want to play a stereo signal upmixed to use all channels connected. The stereo option will allow the sub to be used. I would suggest you turn off the auto function on your sub and with music subs need to underpin the music as much as presenting the deep bass.

You will be getting a PCM signal from any CDs played.


Active Member
sorry, probably not explaining myself very well.

all this is based around audio from tv/sky/netflix etc,

if I watch something on either of these sources encoded in 5.1, then everything works as expected, sub plays properly etc.

if I then go and watch something on sky like food network or something that broadcasts in stereo, or bbc one in dolby 2.0, the receiver pics these up as stereo sources and outputs them to the front 2 speakers

I then have set the receiver to upmix this stereo content to dolby surround, to make switching between a PCM/stereo tv channel, to a 5.1 encoded channel less apparent, its distracting when you switch channels, and sometimes the sound comes out of the centre (true 5.1 broadcast) and then out of only left and right on other channels - and this works ok, but the sub level always seems so low on the upmixed stereo compared to a discrete 5.1 signal

I checked the settings on the receiver just, and the sub level was set to -7, and the gain dial on the sub set to about 10 o'clock, so just under half (starts at 7 o'clock then goes till it gets to 5 o'clock) so I have increased this to zero in the receiver, and turned down the gain on the sub to just under 9 o'clock and will see how I get on?


if I then go and watch something on sky like food network or something that broadcasts in stereo, or bbc one in dolby 2.0, the receiver pics these up as stereo sources and outputs them to the front 2 speakers
If you engage Dolby Surround then that will upmix all stereo Dolby signals to 5.1 or to how many speakers you have connected. This should happen with all Dolby stereo signals. Scroll through the options on the movie button on the remote. If you select Dolby Audio Dolby Surround then that will upmix and will remember that setting for next time it receives a Dolby stereo signal. You will see DD + DDS in the fascia display, I'm going by the display on my model, the 2500 may differ slightly.

Not all stereo outputs from some channels are Dolby, some are just PCM stereo especially SD channels. The same also happens with the iPlayer.
cheers, that's what I have done where I mention "set the receiver to upmix this stereo content to dolby surround"

Its just when this mode is engaged with 2.0 or PCM tv programmes, I get this sub level issue
Just leave the sub switched on.

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