Requesting Information on How to Use REW Measurements to Determine if My Room Requires Acoustic Treatments

The RT60 graph can help show frequency bands where the decay times are long and may benefit from treatment. For advice on which treatments and where to place them the treatment manufacturers can help, some will look at your measurement data.

Below is a ‘waterfall’ chart generated by REW.
It is a 3-axis chart that shows frequency, SPL and decay.

For the purposes of gaining insight into your concern about treatments, you would mostly be concerned with the last one, decay.

Too much decay can be mitigated in a variety of ways. I will let you read up on that if interested. But one of the leading ways to treat long or extended decay is with room treatments. Treatments can absorb soundwaves which converts them to heat. As such, they do not reflect back into the room. This has the desired effect of lessening sound waves bouncing around the room (also known as echo)

The longer the sound bounces around, the greater the decay

Below is a chart of my HT. Sorry, my before image is not available to me currently. But this is how it stands today. Note the third axis or ‘depth’ of the chart. That axis is time. As a general guideline, you don’t want anything greater than 300-400 ms (milliseconds)

As you can see, my HT is ok above 40 hz. Decay times are around 300 ms. Below 40 hz I have a very poor bass profile with decay times exceeding 500 ms.

This is not entirely unusual as managing, or treating, bass frequencies is notoriously difficult. Plus, I have my bass turned up so loud it’s crazy.

I highly recommend saving off different charts before you start your treatment journey (RT60, waterfall, etc). Then you can document in an objective way how you have improved your sound signature.

But anyway, here it is. I hope this helps.

re low frequency mitigation, acoustic fields dot com have the best solution I've seen, and they provide DIY plans if you want to go that route. I'm prevented from posting a link but it's easy to find on the website (they occasionally have discount offers which I tried to post)

To apply this device one needs its characteristics. First of all - absorption capacity by frequency. The main disadvantage of such a devices - low efficiency and wide band range, if you try to apply this to low frequencies issues. One more inconvenience - you will have to find the best place for this device(s) position in the room. If your room is small, then it may be a problem. In case your room has a simple shape - like a shoebox, for instance, you better to use REW for simulation, but it's necessary to consider perturbations, which take a places inside the room - furniture, doors and windows. Besides, you need to know the noise frequency distribution in your room too.