Mattress against the wall - MDAT attached

#1

Hi guys!

I'm just getting started here, in a small apartment, with a mattress leaning up against the wall behind my listening position. I am a video editor but I've always been passionate about audio. Even in the car, I've changed all door speakers, added a woofer, installed two amps and a DSP and tried to tune by ear. But now I purchased a PRM1 and would like to take a more structured data based approach to both the car and the computer room this post is about.

No idea how to read the graphs yet but I am about to start studying them and learning as much as I can on my own. I did follow the guide and generated the attached file. I do spend quite a bit of time at work as a automation controls technologist, analyzing fast sample rate signals in industrial machinery so I am hoping that will help my learning curve here. I am however curious to know what you are seeing about this space at a quick glance, and is the mattress helping or is it making things worse? What should I do first?

Thanks for your time!
Bogdan

full set.mdat: (12.56 MiB) Downloaded 94 times

full set.mdat: (12.56 MiB) Downloaded 94 times

#2

a full size mattress which is filled (not simply springs) can absorb quite a lot of LF energy.

overall - with the sub - the response is decent +/- 8db with 1/3 smoothing and if you don't have the first reflection points covered top and sides, then you'll want to add those. the desk (the 1.5ms reflection) is likely your desk but the longer reflections are down about -20db so the mattress is doing its job. you should look at corners (wall-wall and wall-ceiling) as places to increase LF absorption as you have a lot of energy still to reduce.

#3

gullfo wrote:Source of the post a full size mattress which is filled (not simply springs) can absorb quite a lot of LF energy.

overall - with the sub - the response is decent +/- 8db with 1/3 smoothing and if you don't have the first reflection points covered top and sides, then you'll want to add those. the desk (the 1.5ms reflection) is likely your desk but the longer reflections are down about -20db so the mattress is doing its job. you should look at corners (wall-wall and wall-ceiling) as places to increase LF absorption as you have a lot of energy still to reduce.

Thank you for your time and analysis. I will work towards deducing these things from the plots on my own as well.

A few questions:

1. I have my subwoofer phase inverted currently, does the data support this is the optimal setting for my environment?
2. Are you able to tell if my crossover point is ideal or if there are any adjustments I should make ?
3. Is there anything I could do with Equalizer APO at this point to improve sound? A few hours after I posted my measurements last night I got some news that will require this room to be repurposed within the year unfortunately (and fortunately), so I may have to fall short on what is sensible of doing in terms of acoustic treatment.

#4

not sure what your level of acoustics treatment is besides the mattress, but if temporary, then more wall and ceiling mounted absorbers which are little more than picture hooks or some small brackets to mount.

overall the response is consistent across the spectrum so whatever the settings are they are a good fit. could you do more? sure, taking off the smoothing, there are a few points with higher energy that could be backed off with EQ - re-checking around to the room to see if there is any drastic change impact any other listening positions like a couch etc).

#5

Thank you for your feedback! There is no acoustic treatment besides the mattress which already happened to be here and was about to be moved away, when I thought, let's see what it does for the sound. The room is however very small, and there is a lot of stuff in here. I will look into more absorption but it looks like you are suggesting bass traps for the corners, and some regular absorption for walls and ceiling.

#6

#7

Could bass traps ever be used to return some bass to the already set up listening area, or that's not how it works?

#8

typically the listening seating is some form of couch - which is a bass trap :-)

and the modal distribution in a room doesn't usually favor that location if the primary listening position is the front of the room. as far as improving the LF response in the back of the room - an addition subwoofer tuned to that location (and not interfering with the front critical listening placement) could be an option.

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