Nasty room mode with near field speaker in the corner. Is there anything I can do?

[oohlou]

What can I do to improve the performance of a near field speaker when it is in the corner of the room?

I am in my office most of the day everyday. My office serves many purposes: actual office for work, pinball room, PC game room, listening room, and chill area for 1-3 people.

The room used to be setup like this:

(the hatch pattern boxes are the speakers) The audio quality was great. Those extra 2 chairs were often in the way though and here was barely enough space for VR.

So, I recently moved the furniture. It is now setup like this:

For everything but audio this is the superior setup. The extra chairs feel less in the way, much more room for VR, and the room feels much less crammed. The problem is that sound quality just isn't nearly as good.

I'm using JBL LSR305 through a miniDSP SHD (I also have a Rythmik L12 sub under the pinball machines). I have the JBLs up on blocks on the desk to get them to ear height. The upper bass is getting massacred by a room mode (?) in the 100 to 250Hz range. The exact frequency changes depending on where I put my microphone but is always there. Dirac and some manual DSP filters don't seem to help much or I am doing it wrong. It seems I'm sitting too close to the speaker which is too close to the corner. Is there anything I can do to fix the sound without rearranging the room? I like to fix it with existing equipment but I'm willing to try different speakers (such as one with front ports?) if there is reason to believe it will significantly help.

 

[RayDunzl]

Do you hear it, or just find it visually unacceptable on a chart?

 

[oohlou]

That graph was a measurement right at the speaker with me manually playing around with REW and Equalizer APO to try and get a flat graph.

However DIRAC's measurement is what made me start to focus on that dip as the problem:

Yes, I can definitely hear something wrong. Quite likely there is more to it than just this one room mode but for sure I can say the speakers don't sound nearly as good in this position than they did in the previous position. I don't have a good audio vocabulary to describe the deficiencies accuracy. However, I was able to find an old measurement to show how much better they were in the other position.

So this is single point listening positions measurements. Red is DIRAC on, Blue is DIRAC off, teal is an old measurement from when the speakers were in the other spot. (I think the old measurement is the average of few measurements so it isn't apples to apples comparison but even when I average multiple positions those big dips don't go away)

 

[oohlou]

I am happy to report I had a major breakthrough. I did a few things which greatly increased the quality of sound. Still maybe not as good as it was in the other room position but substantially better.

- I plugged the port on the left speaker in the corner
- I inverted my subwoofer channel
- I ran a few sweeps moving my subwoofer around ultimately moving my sub away from the front right corner a few feet to the left
- I was running DIRAC wrong. I was staying in my chair during the test which for some measurements put my head between the speaker and the microphone. This time I would quickly get out of the way (it seems strange they don't have a delay function on the measurements).

The difference is big. I wouldn't say the blue line sounded "bad" but you know once you get used to listening to really great audio quality when you listen to okay audio quality it just doesn't hit the spot.

Blue is where I was earlier today. Red is my happy place!

 

[Hipper]

I don't think you will ever get a balanced sound like you had in your first set up without adding some sort of room treatment. This is because the left speaker will produce side wall reflections that will be added to the direct sound, whilst on the right there are no reflections, hence the sound from the left will be louder. Whilst this applies mostly to frequencies above around 250Hz it will impact the sound you hear at your chair considerably.

You could perhaps balance the sound using Dirac - is that possible? Alternatively put some material that can absorb down to at least 250Hz immediately next to the speaker. It only needs to be the height of the speaker and at a guess one foot long. The alternative is to put something solid, like a thick piece of wood or a mirror, in a similar position by the right speaker to get the same sort of reflections.

As far as your bass goes, looking at your latest graph, it's possible that the dip at around 160Hz may not be heard as it is quite narrow, whereas the wider dip at 82Hz may be heard. You can get test tones that you can listen too to hear if these really do have a sonic impact:

https://realtraps.com/test-cd.htm

Frankly, if you were really happy with the sound at the first arrangement I would return to that and put up with, or find another solution to, the chair positions. The sounds at the other chairs may also benefit, if that is a consideration.