2nd sub to help the void in the room?

[tommyboy81]

So sadly its happening because of where I sit in the room. I can't move my seat any further back due to the bed. "Bedroom setup"

After a peak at 45Hz it slopes downs 15/20dbs at 60Hz and stays that way until 72Hz then slopes back up 15dbs.

Example: 45Hz- 81dbs
60Hz 64dbs

When running REQ, if I move the mic back a foot a lot of the void goes away. But...because of that the void will try to start in the 110Hz range

Will a 2nd sub help at all with any of this? I feel like it will make it worse.

[oddbox83]

I believe that's what a 2nd sub in a different location to the first is for. Not to pump up the bass, but to even out peaks and nulls.

I'd like to know more on this myself from those who know more, as sub placement in my main viewing room is problematic. I can't have thudding bass because of the neighbours and wonder if a 2nd sub would give me better bass without more bass. Maybe I could even have less volume from the subs if the bass performance was consistent rather than a single sub having to fight the room at it's current calibrated setting?

[gotmule]

Adding a 2nd sub is a good way to correct challenges with room modes. Dr Floyd Toole, who has written a few books on sound, was one of the first big proponents of this. There are a lot of technical aspects in his explanation, but here is a link to help explain why this is an effective approach.

I have been using multiple subs for close to 20 yrs, and am a firm believer.

https://www.audioholics.com/room-aco...-multi-sub-sfm

[tommyboy81]

I wasn't sure it would do that knowing that when I put the sub on the other side it still has the same void and make it worse. Especially if its at the same Hz.

[tommyboy81]

On my back wall I have a couple of GIK 244 bass traps and 1 GIK Moster trap. Took the 244s down and that made an improvement to that area. But did create a sharp null at 90Hz

I didn't completely take the 244s out the room, just put them up front. Wanna try them out of the room. Wondering what will happen if a take the Monster trap out. And also what the higher frequencies will be like because of it.

[hometheatergeek]

Hi Tommy,
What I would first recommend is to manually change the subwoofer distance in the AVR. You stated the dip goes away if you move the mic back a foot so add a foot in the distance setting and re-measure. Continue to manually adjust to where you get a flatter response. Audyssey sometimes gets this wrong. Basically what is happening is the sub is not in phase with the front channels.

[gotmule]

Originally Posted by hometheatergeek

Hi Tommy,
What I would first recommend is to manually change the subwoofer distance in the AVR. You stated the dip goes away if you move the mic back a foot so add a foot in the distance setting and re-measure. Continue to manually adjust to where you get a flatter response. Audyssey sometimes gets this wrong. Basically what is happening is the sub is not in phase with the front channels.

Might be worth a shot, but adjusting distance impacts time alignment and not phase alignment, as they are two separate things. Adjusting distance usually does not impact phase of the sub in the AVR. If the sub has a manual phase adjustment, it might be worth experimenting that way as well, then run Audyssey.

https://www.prosoundweb.com/time-phase-alignment/

https://www.avsforum.com/forum/113-s...-distance.html

[hometheatergeek]

Originally Posted by gotmule

Might be worth a shot, but adjusting distance impacts time alignment and not phase alignment, as they are two separate things. Adjusting distance usually does not impact phase of the sub in the AVR. If the sub has a manual phase adjustment, it might be worth experimenting that way as well, then run Audyssey.

https://www.prosoundweb.com/time-phase-alignment/

https://www.avsforum.com/forum/113-s...-distance.html

Ok maybe I used the wrong wording but if there is a dip around the crossover point i.e. 80Hz then the subs have an incorrected "audio vs physical distance" setting in the AVR. I have 4 subs placed asymmetrical in my room all set at 0°. In order to get the bass sounding like it is coming from the main L/R speakers I had to adjust the distance AFTER running Audyssey.

[tommyboy81]

right now I have the sub distance at 17.5 feet. The calibration thing thats on this AVR put it at 7 or 8 feet? Speakers are 6.5ft and everything was all out of whack. It had the speakers at 50hz crossover too

Different phases of course give me different distance settings. usually I get decent numbers at 18ft, 22ft, 28ft and 29.5ft. And graphs mostly look the same.

That big void is actually 2 dips I guess that prevents the middle part from going up. I call it vampire teeth by the way it looks.

upped dip at 90 I got fixed a little but caused a dip at 95-100 and a dip 150. No matter the crossover that dip is the dip is there Seems like raising that trouble
section up some causes another to go down.

And no matter what that 80hz peak is still there. At least its not boomy on the sweeps

[tommyboy81]

To give a little update. After moving the back acoustic panels, moving sub here and there which made the graph better but I found out why I was getting the void.

Finally geting the 60 to 70hz range to where it needs to be I find out I get some serious bass reflection in the front right side of the room. Acoustic panels in the area doesn't do anything.

Should I try placing my bluray disc bookshelf in that corner? Would that help?