Are you talking about a room the shape of a square? Why would you sit so close to the center to begin with? Also sitting in the center doesn't automatically result in a lack of low frequencies.

As long as the room is rectangular then the answer is yes, there are different ways to make up the difference ( you could always sit further behind the center like in a media/movie space and still be able to hear the bass with a multisub setup and digital management). You will definitely treatment on the backwall though.

I was talking about small rectangular rooms. In small rooms, because of monitor speaker cabinet depth and front wall bass trap depth, the listening position is often close to the center. Sitting at the back of the room is often not possible either if you want to install the monitors at +/-30 degrees (room width is too small); so in this configuration the listening position is still close to the center.
To sum up, in most small rooms it is difficult to be far enough from the center, and decently deep bass traps (30-60 cm depending on the wall) make this situation even worse.

So it's good to know the use of subwoofers can also help when placement cannot be ideal.

How small are we talking about? And what cabinet are you describing?
Because a room the size you are describing would be too small even for necessary treatment depth.

A multisubwoofer setup ( at least 4 subs or more) with digital management and minimum phase EQ can definitely work wonders in smoothing out the bass response and decay, but you still need some treatment in the space. Also if the room is tiny, using 4 or more subs will not be possible because of the depth of the subs alone. Also if you need to drive the modes in the corners, there can't be a door in the corner obviously.

If you look a few posts back, you can see what kind of bass I’m getting in a small room, listening position in the center

For example my room is 450x305x235 cm before treatment. Bass traps are 50 cm deep on the front wall, 30 cm deep on the sides and ceiling, and 60 cm deep on the rear wall (all surfaces are fully covered except the floor, and there are also slats).
K+H O300 monitors at 30 degrees result in tweeters that are 44 cm from the front bass trap (94 cm from the front wall). The listening position is 159 cm from the front wall, so about 64 cm from the center of the room.
When putting the measurement microphone closer to the front wall, the low frequencies increase in level, but the ideal position (for bass) is too close to the monitors.

As a test, I can try to use old 5" compact monitors as satellites and the K+H O300 as "subwoofers" (on the floor, with the driver facing the front wall), with whatever software DSP processing (crossovers, all pass filters, delays). Compared to the current setup, it allows to sit 22 cm further from the center. If it works well, then I can get more adapted monitors.
Otherwise, there is not much to do for improving this room I'm afraid.

Thanks
It really demonstrates how all small rooms are very different and unpredictable. In my room, no matter with or without acoustic treatment, for any speakers position and listening position, it was never possible to have enough low frequencies (and that's with speakers that do have a good low frequency response). It is better with full acoustic treatment and current placement, but still somehow bass-light (when mixing, I have to take this in account, which is a shame because the whole point of good speakers and acoustic treatment is to 100% trust what you hear)

Yeah, I hear you. My speakers position are pretty much in the corners of the room and my listening position is a bit more forward than the 87% rule, so my stereo field may a bit exaggerated or my phantom center may be off, but I like the way it sounds.

The biggest setback for my room acoustically was the floor to ceiling modes/floor to ceiling bounce. The treat man I have helped with that I think. A bit of a dip at 220 and a massive dip at 500hz

If your bass level is rising closer to the front well then in your case its not a bad thing right? If its the modal pressure that is boosting the response, then the peaks can be fixed with minimum phase EQ to smooth them out. As long as you don't setup 25% from the front wall you should be ok.

But with 50 cm of treatment on the entire wall you are still getting peaks in the first and second Length modes? Is the room made out of concrete or a dense material? Is it the correct flow resistivity?



The issue is if you need to drive the modes, your subs have to be able to increase the level (for example if they are in a null) and if your subs (K+H 0300) aren't up to it they can and will distort. Not all subs are created the same. That is why with 4 of them is recommended and they don't have to work as hard. If you are not careful you could drive the K+H 0300 pass the point they are designed to work optimally.

Unfortunately the ideal position (for bass) is so close to the front bass trap and the speakers that it is not practical at least with the monitors I have. Maybe with shallower, less wide monitors (not even sure; but I will try with my former 5" compact monitors)

Yes, and actually even the simulators tell it. It is only porous absorption, so there are better solutions (including mixed porous / pressure traps, etc).
But it is not really a problem because they are attenuated a lot.
Biggest problem is the listening position that results in too much general bass roll-off, second problem is the floor interference (the latter can be fixed even with one subwoofer, the former I am not sure in this room but will try).

It is made out of bricks, covered by plasterboard spaced randomly depending on the wall (except on the ceiling) -- something highly asymmetrical with a +/-30 dB frequency response and very aggressive sounding mid frequencies before treatment.

Yes (3000 Pa*s/m2 for 50 and 60 cm traps, 5000 Pa*s/m2 for 30 cm traps)


Sure, but this is just a test really, and yes I will do it at low level because the O300 are not meant to be used as subwoofers and they are not really loud anyway. If the results are good, then I will consider getting real subwoofers (or perhaps build some, but I have no experience about this), maybe some small satellites that would allow to sit closer to the front wall, and maybe a hardware bass management / room EQ processor. But this is a lot of money so I must be sure it really improves things, hence this quick and dirty test with the speakers I have here.

Ah bricks and plasterboard. Makes sense.
For porous treatment in small concrete rooms, I remember reading Phillip Newell saying he recommended 36" of treatment everywhere except the floor for small rooms.

I would still test if its better to push the monitors as close to the treatment as possible. In order to tilt bass response.