Help: Speaker/Room Issues with Suckout 150hz to 50ish hz

[jmdesignz2]

Ran REW with 10 repeats and found Speaker/Room Issues with Suckout 150hz to 50ish hz

Stack is Macbook pro>USB> Topping DX5 II>Topping A70 Pro>Buckeye NCX500 mono blocks>BMR Tower Speakers

Room diagram/speaker position and REW plot below

These speakers are supposed to be a flat response in-room
Why would there be such a huge suckout? Looks like more than 30dB?

L shaped Room is 12 x 21 ft open at the top and bottom with the BMR stack on the long side of the L.
There is a stack of foam and foam tubes in the top apex of the L of this room (corner right of the speakers)
Large foam filled couch at the base of the L (left of speakers) and another on the right side of the vertical (seating positions).

 

[jmdesignz2]

Ok. So I moved these 44” into the room and the suck outs reduced to about 4-5dB

I’ll have to figure out something better though lol

 

[MarkS]

Can you move the speakers (and the listening position) to the left or the right? Nulls tend to congregate in the center of any rectangular room, so being off-center can help. Similarly, can you move the listening position closer to the back wall?

 

[jmdesignz2]

Speakers are off center, more towards the right side of the room. The right channel is 7ft 6in away from the right wall.

Listening position is already right at the back wall on a couch.

The right side corner(front wall) has a small doorway/short hall opening across from it
The left side corner (front wall) has a very wide opening- about 10ft that leads to the large foyer/dining area.

Idea for using Six rockwool acoustic panels. Each 6" thick and 2 x 4 ft dimension

I am thinking the corner to treat would be the right side with a 6" thick floor to ceiling bass trap panel place diagonally across the corner. Then place 6" thick panels 4ft high in a V shape behind each speaker with each speaker inside the V

 

[Flaesh]

such a huge suckout?

Strange and terrible.

Is there a subwoofer or not?

 

[jmdesignz2]

made and installed 6" thick 2x4 ft panels behind each speaker, moved speakers to 35" from front wall. Installed floor to ceilling bass trap in front right corner

here are before and after REW scans (without any sub)
interesting that the Phase has also gotten much smoother

 

[LevityProject]

Nice! I believe you've discovered something important about room acoustics. Thank you for posting your journey

Some thoughts (which can be debated ... this is just what I think might level up the experiment): The treatment behind the speakers and bass traps seems like it's dealt with the room null. You are now getting more direct sound from the speakers.

What are the speakers??

Ironically, if you now move the speakers closer to the wall, you might find that the lack of sub bass between 60-100hz will improve. If you notice a change, measure it to be sure. The next improvements toward your goal may come with this:

• Try the speakers closer to the front wall (not farther)
• Measure one speaker at a time (critical ... if you measure two speakers, you are measuring an array).
• Measuring a single speaker can give you a core baseline to jump from.
• If you listen to check/reference in Stereo, pick music that sounds amazing in mono.

You’re doing the right kind of work. Keep going slowly, changing only one thing at a time, and do audible checks with each round. The graphs can confirm what your ears are telling you, but don't take the graphs as absolute truth - but instead as a ballpark and as showing you something, whether it's a reality of the room, the speaker or your measurement rig. As long as you are at least using a decent measurement microphone and a recommended DAC, you'll be sneaking out of the realm of confirmation bias

There are still plenty of gotchas in speaker and room measurements, but I love that you are doing this. Bravo, friend!

 

[audio_tony]

One side of my lounge has a 20ft drywall which creates dips from ~150 to 300Hz. The wall is apparently resonating at a specific range of frequencies.

I have been advised to add mass (the wall is hollow - not even filled with insulation).

OP, is there a drywall in your listening room?

 

[LevityProject]

One side of my lounge has a 20ft drywall which creates dips from ~150 to 300Hz. The wall is apparently resonating at a specific range of frequencies.

I have been advised to add mass (the wall is hollow - not even filled with insulation).

OP, is there a drywall in your listening room?

That’s rough to have no insulation behind the wall. But the irony is that fixing the problem of resonance created by the space between wallls doesn't mean ripping out all the drywall and putting insulation everywhere.

When insulation (such as Roxul) is exposed in panels or placed in corners of a room (even if it is wrapped in fabric), it can absorb sound energy and reduce echoes, instead of letting sound bounce around the room. In corners, it helps tighten up bass and reduce how strongly room modes show up.

Insulation hidden behind sealed walls mostly helps with temperature and sound leaking between rooms, but it doesn’t do much for echoes or clarity inside the room itself. It may help a bit in that the resonance of the wall can be reduced, but there are more economical ways to achieve that goal ...

 

[audio_tony]

Insulation hidden behind sealed walls mostly helps with temperature and sound leaking between rooms, but it doesn’t do much for echoes or clarity inside the room itself. It may help a bit in that the resonance of the wall can be reduced, but there are more economical ways to achieve that goal ...

The plan is to try 3 or 4 of those heavy sound deadening panels one can buy. They look ok too.

I think that adding mass to the wall might (in part) solve the problem, but at the same time I sense it might create issues elsewhere in the audio band!

 

[jmdesignz2]

One side of my lounge has a 20ft drywall which creates dips from ~150 to 300Hz. The wall is apparently resonating at a specific range of frequencies.

I have been advised to add mass (the wall is hollow - not even filled with insulation).

OP, is there a drywall in your listening room?

The wall closest to the speakers is thick concrete block with a layer of drywall

 

[audio_tony]

The wall closest to the speakers is thick concrete block with a layer of drywall

That shouldn't be a problem then. I wish mine was brick!!