Subwoofer gain and bass control on amp

willhub · 21 Jul 2019 at 11:04

So I've done a shuffle around in my room and the position I could have sworn my subwoofer was weak in is now optimal for where I can position it resulting in reducing bass by -2 to -4db on the amp.

However, depending on the source, sometimes leaving it on default 0db is best whilst some sources need at least -10db to avoid shaking the room down.

What i want to know is that by leaving the subwoofer gain as is and changing the bass volume on the amp, will I be losing out on quality or certain frequencies?

Thanks

hornetstinger · 21 Jul 2019 at 17:23

Setting -10 means your sub volume dial is too high. Perhaps for room nodes so one scene is boomy another bass shy?

willhub · 21 Jul 2019 at 17:39

hornetstinger said:
Setting -10 means your sub volume dial is too high. Perhaps for room nodes so one scene is boomy another bass shy?

Some are really loud some shy on bass, so if I adjust gain lower then I guess itd be the same outcome?

hornetstinger · 21 Jul 2019 at 17:52

But I'm talking about your sub level out being too high possiy clipping the amp signal

willhub · 21 Jul 2019 at 17:56

hornetstinger said:
But I'm talking about your sub level out being too high possiy clipping the amp signal

Are you referring to the level on the amp?

There is only 2 levels no? Subwoofer gain (On the sub) and bass level on the amp. I usually have the bass level -4, evidently I could lower the gain so I can put the bass back to 0 but some tracks would then require me to raise the bass level on the amp.

lucid · 21 Jul 2019 at 20:00

It doesn't matter if you change the level on the sub or via the amp, you've still got an awfully large amount that you're changing the whole system by when there's a 10dB difference between sources.

Did you mean sources?

DTS routinely recorded the LFE track 10dB, but that's an audio signal difference rather than a source equipment difference.

There can be a difference in the overall signal level between sources. A lot of AV amps have a source level trim feature to help even things out. Unless it's very obviously louder or quieter, it can be tricky to assess the level based on what's happening with all the channels combined when playing normal program material. A lot rides on the sound mix of the program content. For example, movies will generally have a more active LFE channel than say a TV news- or quiz- program, but you'll get two distinctly different impressions of the LFE playing the movie Saving Private Ryan compared to the the movie Sense and Sensibility despite both being played from the same source device. There are sound meter apps for smart phones that use an averaging reading over several minutes that can help.

I think the problem could be related to the volume level which is exciting some room modes once the volume gets above a certain level. Equalising the volume levels between the source devices will probably help.

willhub · 21 Jul 2019 at 21:26

Perhaps I need a better amp? Have a CEOL Piccolo DRA N4 at the moment

lucid · 22 Jul 2019 at 07:01

I was thinking you have an AV receiver, but your system is 2 channel music. Forget what I said about LFE and source-matching.

How are you making the assessment that the sub position is now optimal? What has changed in the room to make it that the same position previously was a bad choice, but now it is good?

willhub · 22 Jul 2019 at 08:05

lucid said:
I was thinking you have an AV receiver, but your system is 2 channel music. Forget what I said about LFE and source-matching.

How are you making the assessment that the sub position is now optimal? What has changed in the room to make it that the same position previously was a bad choice, but now it is good?

Well it's probably not optimal for that room but as far as where I can position it it's optimal. I slapped the sub on the chair where I sit when watching tv and walked around the room, I find the level is much better when I stood to the left of the TV and when I moved the sub there it indeed was. You don't want to turn it up as loud to hear bass.

Before where it was you'd turn the bass up so you could hear it properly then go to the kitchen and it was thunderous, that's gone now.

lucid · 22 Jul 2019 at 09:37

willhub said:
Well it's probably not optimal for that room but as far as where I can position it it's optimal. I slapped the sub on the chair where I sit when watching tv and walked around the room, I find the level is much better when I stood to the left of the TV and when I moved the sub there it indeed was. You don't want to turn it up as loud to hear bass.

Before where it was you'd turn the bass up so you could hear it properly then go to the kitchen and it was thunderous, that's gone now.

The loudness in the kitchen; that's a good demonstration of room modes in action. The dimensions of any domestic-sized enclosed space will produce places where bass frequencies peak and other places where some frequencies seem to disappear.

When doing the walk-around-the-room thing were you always standing, or did you have a listen when crouched down too? I mention it because room height creates its own set of peaks and troughs too. There can be a difference in sound when standing compared to sitting.

willhub · 22 Jul 2019 at 11:17

lucid said:
The loudness in the kitchen; that's a good demonstration of room modes in action. The dimensions of any domestic-sized enclosed space will produce places where bass frequencies peak and other places where some frequencies seem to disappear.

When doing the walk-around-the-room thing were you always standing, or did you have a listen when crouched down too? I mention it because room height creates its own set of peaks and troughs too. There can be a difference in sound when standing compared to sitting.

I didn't sit down admittedly. The current position most certainly isn't optimal for the room, the most optimal place would likely be on the wall that is neighbour facing so no go.

The current location produces the most bass out of any location I can put it. Just the getting all sound sources equal with bass is a nightmare.

I also have the sub on sorbothane hemispheres which did make bass a bit more punchy.

In current location the best bass is where seated for tv, at computer desk and outside on the balcony, the prime spots of the flat.

Definitely need a house rather than a crummy flat here in media city with creaky floorboards.