There have been some good suggestions here. I recommend you become familiar and comfortable with REW. It is a positive step in the right direction. Also free and really useful is HolmImpulse I am using Omnimic from Parts Express but is not free, about $300, because it also allows me to measure Thiele/Small parameters. This provides tone bursts and measures room response in a second.
I have found the ability to read CSD plots (waterfall) very useful when adding acoustic treatments. Not only in how the frequency is altered but more importantly how the decay time is shortened. An untreated room has sound bouncing around with early and later reflections, confusing the information leading to smear and congestion, ruining soundstage and imaging.
All rooms suffer from this and taming these long decays makes a such a difference that unless you have heard it, is difficult to conceptualise. You have a room with reasonable dimensions that can be sorted out. No need to be overly concerned with a low ceiling unless you use a trampoline to keep fit!
A statement you made earlier about matching speaker to room or room to speaker is, I feel, not the way to approach this. There is a scientific target to strive for with room treatments and measurement is the only way to achieve this. Some of the advice offered here is well intentioned but misleading. EQ can not sort out overly long decay nor dips in the response. If you increase the power into a dip/null it will just cancel with the same power, leaving the problematic dip there but sapping the amplifier's power and driving it towards clipping. Taming the peaks by reducing power will flatten the response, but the sound is still taking to long to decay.
People often suggest drapes and wall to wall carpeting. They often do more harm than good. These are narrow-band absorbers, where what is required is broad-band absorbers. Take wall to wall carpet. It is thin with no air gap so it becomes a high-Q narrow-band absorber, and because there is a lot of it those freqs. are mostly lost. A nice thick rug in the listening area is fine. To sort out the floor to ceiling reflections consider the idea below. Absorption is needed on either the front or back wall or on both. The third axis to consider is the two side walls but in your case they are far away and not so troublesome. Dispersion/ diffusion would work well here. Drapes can help and also blend in nicely with the decor but a single thin drape will not do much. Use a 2 or 3 rail set up with thick material. The multirail provides a lot more material and, importantly, spaces the layers at different distances from the wall, broadening its freq. of absorption.
You mentioned a blanket positioned on the ceiling. If you replaced this with a proper broad-band absorber about 4ft X 8ft X4" thick and filled with OC73 or equivalent, you would hear an immediate improvement and see it on the response plots. There are many DIY articles for building these and bass traps on the net. Check out super-chunk bass traps. Simple and cheap if you are at all handy. Bass traps are the true stars when treating a room. Can't really have too many.
Sound propagates in different ways depending on frequency. below the Schroeder freq. it is modal, transitioning to a reverberant field above that. When low freq's are present in a room, there is combining, some constructive and some destructive resulting in peaks and nulls. If its a full null then that is information missing and as previously mentioned EQ can't get it back. But bass traps can. They will smooth out the response, which again can be seen and heard.
It may have occurred to you that how do you know when to stop with treatment. It is not guesswork and there are tables that will give you a target to aim for. The aim is to achieve a reduction in decay time across the full freq. spectrum. In your size room it will be about 400ms. where the sound is required to decay by 60dB. Known as T60. This is great fun to do. As you introduce some bass traps you will notice on the waterfall plots that some previously missing information (nulls and partial nulls) is now starting to return and that some problematic peaks are being tamed. The audible result defies credulity.
One last thing, Take no notice of Kenjit, I think his lobotomy went wrong.
I have found the ability to read CSD plots (waterfall) very useful when adding acoustic treatments. Not only in how the frequency is altered but more importantly how the decay time is shortened. An untreated room has sound bouncing around with early and later reflections, confusing the information leading to smear and congestion, ruining soundstage and imaging.
All rooms suffer from this and taming these long decays makes a such a difference that unless you have heard it, is difficult to conceptualise. You have a room with reasonable dimensions that can be sorted out. No need to be overly concerned with a low ceiling unless you use a trampoline to keep fit!
A statement you made earlier about matching speaker to room or room to speaker is, I feel, not the way to approach this. There is a scientific target to strive for with room treatments and measurement is the only way to achieve this. Some of the advice offered here is well intentioned but misleading. EQ can not sort out overly long decay nor dips in the response. If you increase the power into a dip/null it will just cancel with the same power, leaving the problematic dip there but sapping the amplifier's power and driving it towards clipping. Taming the peaks by reducing power will flatten the response, but the sound is still taking to long to decay.
People often suggest drapes and wall to wall carpeting. They often do more harm than good. These are narrow-band absorbers, where what is required is broad-band absorbers. Take wall to wall carpet. It is thin with no air gap so it becomes a high-Q narrow-band absorber, and because there is a lot of it those freqs. are mostly lost. A nice thick rug in the listening area is fine. To sort out the floor to ceiling reflections consider the idea below. Absorption is needed on either the front or back wall or on both. The third axis to consider is the two side walls but in your case they are far away and not so troublesome. Dispersion/ diffusion would work well here. Drapes can help and also blend in nicely with the decor but a single thin drape will not do much. Use a 2 or 3 rail set up with thick material. The multirail provides a lot more material and, importantly, spaces the layers at different distances from the wall, broadening its freq. of absorption.
You mentioned a blanket positioned on the ceiling. If you replaced this with a proper broad-band absorber about 4ft X 8ft X4" thick and filled with OC73 or equivalent, you would hear an immediate improvement and see it on the response plots. There are many DIY articles for building these and bass traps on the net. Check out super-chunk bass traps. Simple and cheap if you are at all handy. Bass traps are the true stars when treating a room. Can't really have too many.
Sound propagates in different ways depending on frequency. below the Schroeder freq. it is modal, transitioning to a reverberant field above that. When low freq's are present in a room, there is combining, some constructive and some destructive resulting in peaks and nulls. If its a full null then that is information missing and as previously mentioned EQ can't get it back. But bass traps can. They will smooth out the response, which again can be seen and heard.
It may have occurred to you that how do you know when to stop with treatment. It is not guesswork and there are tables that will give you a target to aim for. The aim is to achieve a reduction in decay time across the full freq. spectrum. In your size room it will be about 400ms. where the sound is required to decay by 60dB. Known as T60. This is great fun to do. As you introduce some bass traps you will notice on the waterfall plots that some previously missing information (nulls and partial nulls) is now starting to return and that some problematic peaks are being tamed. The audible result defies credulity.
One last thing, Take no notice of Kenjit, I think his lobotomy went wrong.