Room Analysis-How?

The best source of info and help is the Room EQ Wizard help forums. 

Erik +1

Go to YouTube and search for "tutorial room eq wizard"

I have found YouTube videos by Home Theater Gurus to be helpful. They are home theater centric but the principles are the same.

This should be a good series to follow as the principles apply to home speaker use the same way just different targetting parameters:

Video 1 - https://youtu.be/dmz-vmb2UQI?feature=shared

Video 2 - https://www.youtube.com/watch?v=F-T_lZ3KJjU

You’d need a calibrated mic like a UMIK-1/UMIK-2, a laptop and Room EQ Wizard @rjduncan 

 

You can reach out to the maker of the videos here - Work With Me | Vespers

I hired Nyal Mellor of Acoustic Frontiers for help with room acoustics. He specifically performs room analysis, giving a breakdown in paper and in conversation. He is excellent and professional. Price is very reasonable. We did remotely using REW. He gave me the parameters for measurement, and I uploaded the files to google drive.  

I also recommend reading Master Handbook of Acoustics, which is an easy read, to better understand some useful concepts. 

 

Just for fun, walk around your room and clap your hands. You're listening for any echos. This occurs when two flat walls face each other. If heard, hang a large beach towel on one of the walls (foam panel from Guitar Center, etc. is better).

Repeat process until all echos fixed. 

For $20, download AudioTools for frequency analysis, play a source of pink noise, understand and measure Reverberation time 60. This will put you in the ball park. 
Further assistance can be had through GIK acoustics and will walk you through measurements, hoping to tune your efforts with their products. 

Second the recommendation on The Master Handbook.

Lots of people trust Mitch

https://accuratesound.ca/

lots of people say that the DIY approach will be disappointing as apparently it needs a lot of experience to get it right...

@rjduncan 

Not an expert acoustician, but an engineer and I love math!

If you like what you have, blueprint what you have: seat location in the room, speaker locations, speaker to seat measurement, tweeter to tweeter measurement, L<W< H of room, etc.

There are sometimes conflicting items to juggle but I suggest getting the speakers placed in the room per one of many techniques available. I used 3 of them and they all gave me the same locations within inches. Vandersteen has a well written guide that mimics the videos above. It will give you front wall and side wall locations.

Then, your seat relative to the speakers is important and it can cause some confusion, but the 83% value is a ROT, not a hard law. Tweeter to tweeter distance divided by the tweeter to ear distance at 83% is a good indicator you are headed in the right direction.

Then measure to see where your seat is and another ROT is your seat should be 62% back from the front wall. This helps to avoid peaks or nulls which based on the room length is always going to be mathematically at halfway, quarter of the distance, etc. This 63% does not guarantee magic. At that point if your speakers are pretty close to both approaches, you are looking good.

As mentioned above, do you have any smearing in the treble or echoes going on? Are you using any first reflections absorbers or diffusers? Smearing is often treble gone wild and bouncing all around and can be distracting. You like your sound so perhaps it is under control.

You are curious about your room response but it is a Pandora's box once you start on that path. We typically cannot make the room response flat, but can make it flatter. Not sure where I heard it, maybe from a speaker designer, but a + - 5 db room response is deemed to be pretty good from 20 to 20khz. Most of the problems will be bass related and bass trapping can have a very nice impact on that end as well as draw the midrange into compliance as well.

It only takes 20 seconds to run REW if you have the key components like the mic and a preamp and soundcard. The setup is critical in the REW software and once you get it, then you can always reuse those key controls. The REW start up guide will list some gear like the mic and preamp and cabling to hook up to your stereo preamp to send the signal out for the room mic to pick up. A cheap tripod is handy, and put the mic almost vertical in your chair where your ears are normally and go for it.

Also, try AMROC's site and punch in your room dimensions and you will see all your room modes as you slide your cursor up the piano keys. Remember, the room is like Mother Nature, it always wins and we have to do the best we can to deal with it. Compare your seat locations with some of the room modes driven by the length, width, and height and you can quickly see where you may be dealing with some monster problems and have unknowingly accustomed yourself to those.

I hope you get REW running someday but remember it will look very ugly and can be like staring at a mountain to climb but knowing what is going on and how to treat your room will give huge benefits. Check out my TN 2023 system. I just reworked the bass trapping again and added ceiling treatments and while the response did not show major changes, it sounds even better and makes me weep.

Then the cycle starts over and you crave better gear again! ha

OP,

As others have posted above, REW is all you need. It takes practice and time to understand its power. It's free and all you need is the UMIK (amazon)

At first, it's a pain to understand but after a while you will get used to it and will learn its features you need to tune your room,

I did that "tuning" my room and after months of learning my room, REW told me where the issues are. I consulted companies like ATS for solutions. I got what they recommended and did another REW analysis. problem solved. After my ears got used to the new room treatment, I heard major improvements, like better tighter bass, no more echoes/reverbs and importantly, I heard space between the instruments and vocals are clear and I can hear more into the music. Yes the room is so important that no matter how good your gear is, the Room acoustics can make or break the final sound.

I was so impressed that I suggested that to another audiophile friend of mine who claimed his room is good enough. After running REW, he found out that his room is messed up. Well months later he showed me what improments he made using REW and boy was it worth all the hard work. 

Understanding how REW works is a pain, but you need to know it. It is the essence of what you hear. NOW, if you don't have time for this, use a consultant and pay their skills.

In the end, Room acoustics is serious stuff. 

Lots of thoughtful and helpful feedback here. Thanks to everyone who has posted here thus far. 

@rjduncan - great question and one that involves a lot of learning.

EDUCATION: I'd suggest reading Dr Toole's book "Sound Reproduction" which is about acoustics and psychoacoustic stuff.  A base of knowledge and common sense will take you far.

TOOLS: While others here have recommended REW, I found that it has a steeper learning curve than OmniMic from Dayton Audio and which I prefer to use.  I also prefer it's graphical user interface but both tools should give you the same measurement results. 

While REW/OmniMic come with lots of different measurement charts, my analytical background has me importing the OmniMic measurements into Microsoft Excel spreadsheet for further data manipulation and additional calculations and added Charts.  For example, decibels are logarithmic values that should not be added or divided or multiplied together, so they need to be converted into linear energy first, then perform your arithmetic on them, and finally convert the result back to decibels; this is needed for frequency response and early reflections analysis primarily.  While subtracting a log value from another log value is fine (e.g. take the difference between L and R speakers to quantify their loudness variance across the frequencies), you'll need linear energy values for creating averages or sums such as to calculate "Error Rates" which represents the distance the measured frequency response for a channel is from your Target curve.  Another area of applying linear energy is with Energy Time Curve data for early reflections of 0-10ms which impacts tonal balance and imaging strength with the goal of having acoustical energy symmetry from 1st order and other reflections especially important in unsymmetrical shaped rooms.  More can be found in this article I wrote here:  https://pmamagazine.org/early-reflections-101-the-first-10-milliseconds-that-make-or-break-stereo-imaging/  Please excuse the shameless plug.

WORKFLOW SEQUENCE:  Acoustically Treating a Room - Is there a Work Flow that works best?

Many of us spend a lot of time (and money!) curating the perfect stereo or home theatre setup — reading reviews, visiting shops, asking trusted audiophile friends. Eventually, we piece together a system that should sound amazing…but then we bring it home, and it doesn’t sound as good as it did in the store.  The problem might not be your gear — it might be your room.

Acoustics play a huge role in how your system sounds. In fact, many pros say the room contributes about 50% of the final sound quality. That’s massive. So we start exploring acoustic treatments. Maybe we try a few DIY absorption panels, or maybe we're lucky enough to have a dedicated room where WAF isn't a factor and we can really experiment.

But here's the big question:
Is there a “right” order for treating a room?
Yes — and following a proper sequence makes a big difference.

Over the years, I’ve refined this workflow for both my room and my clients’.

 

• Early Reflections (0–10ms)
  Start with the floor, ceiling, sidewalls, front and rear walls — focusing on first-order reflections. These reflections arrive just after the direct sound and have the biggest impact on imaging and tonal balance.

• Bass Decay
  Use bass traps to reduce overly long decay times. Why? Bloated bass can mask midrange detail, so this step is crucial for clarity.

• Mid/High Decay Times
  Add diffusion and/or reflectors to maintain liveliness. Over-absorbing these frequencies can leave the room sounding dull and lifeless. You want a balance — not an anechoic chamber.

• Frequency Response EQ (the very last step)
  Once the room’s reflections and decay are under control, then (and only then) consider gentle EQ. Aim for each channel to be within ±3dB across the range. Doing EQ first often masks deeper acoustic issues — it’s like painting over a cracked wall.

Most people start with EQ… but trust me, it’s better saved for last.

Here are 2 articles I wrote about taking and deciphering measurements:
https://pmamagazine.org/analyzing-a-stereos-frequency-response-and-decay-times/

https://pmamagazine.org/deciphering-stereos-acoustical-measurements-and-taking-corrective-actions/

Hope this helps . . .

@rjduncan - at the risk of appearing verbose given my long post above, I thought the following testing might be of interest to you.
~~~~
I wanted to evaluate how music sounds using 3 different EQ correction scenarios. This wasn’t an advanced scientific experiment—just a practical comparison for my ears.

Test Scenarios

· Measurements taken using 1/6th smoothing: 6 PEQ filters per channel below 500 Hz, optimized by OmniMic.

· Measurements taken using 1/12th smoothing: 6 PEQ filters per channel below 500 Hz, optimized by OmniMic.

· Measurements taken using 1/24th smoothing: 6 PEQ filters per channel below 500 Hz, comparing OmniMic’s settings to Kevin’s (my own) manual PEQ settings.

Listening Impressions

Here’s what I heard:

· 1/6th smoothing and EQ: The sound was dull, less engaging, and lacked dynamics.

· 1/12th smoothing and EQ: The sound was wonderful—dynamic, clear, and highly detailed.

· 1/24th smoothing and EQ: The sound was slightly more refined and polished than 1/12th, but possibly a touch less dynamic and engaging.
 

A Common Baseline for Comparison

To compare the results more fairly, I applied EQ corrections and then smoothed the 1/12th and 1/24th measurements to 1/6th smoothing—the “lowest common denominator.” Even at this level of smoothing, the results ranked as follows:

· 1/24th smoothing was the best on paper.

· 1/12th smoothing was a close second.

· 1/6th smoothing was noticeably worse.

EQ Adjustments: Cuts and Boosts

I also tallied the total cuts/boosts across the 12 PEQ filters:

· 1/6th smoothing: Total of 20.9 dB (average cut/boost: 1.9 dB).

· 1/12th smoothing: Total of 57 dB (average cut/boost: 4.4 dB).

· 1/24th smoothing: Total of 48.5 dB (average cut/boost: 4.0 dB).

This tells me that:

· 1/6th smoothing oversimplifies the data, hiding peaks and nulls. The result? Smaller EQ adjustments that are insufficient and leave the sound quality lacking.

· 1/24th smoothing reveals far more detail, including larger peaks and nulls, leading to more aggressive EQ adjustments.

Key Points

· Too much smoothing (like 1/6th) masks real issues in the frequency response, causing under-correction and dull sound.

· Too little smoothing (like 1/24th) exposes a lot of detail, which can require higher amounts of EQ. While it refines the sound, it may sacrifice some engagement and dynamics.

· 1/12th smoothing strikes the best balance—it exposes enough detail for meaningful corrections while preserving clarity, dynamics, and musicality - it was my "Goldilocks zone."

Final Thoughts

In my experience, what measures best doesn’t always sound best. For my ears, 1/12th smoothing and its corresponding EQ settings hit the sweet spot. It produced the most enjoyable and balanced sound without overdoing the corrections.

Thanks to everyone that chimed in on this thread.  My wife was out of town this weekend which gave me the opportunity to spend a lot of time on Saturday and Sunday becoming a novice, yet capable user of REW and analyzing my room.  I also bought the Master Handbookf of Acoustics and began to read.  I've already learned a ton!  My analysis this weekend led me to make meaningful changes to my main speaker positions and primary listening spots.  I made sub woofer adjustments in the crossovers and volumes.  I experimented with moving certain furniture around.  I had a large null in the 200-230HZ range in the beginning that I've now worked to an acceptable level.  And then after all the adjustments I applied my ears and tweaked a little more.  My room, which was impressively pretty good before I even started this analysis (dumb luck I suppose, perhaps helped by a wife with good furniture/decoration taste and placement!) sounds better than ever!  This will be iterative over time.  I'm guessing I'll experiment with panels, diffusers and traps as time goes on.  Who knows.  But this was fun, my room is better today and I'm thankful to those of you who posted to encourage and guide my endeavors in acoustical analysis!

@rjduncan   Fantastic!! It is amazing how we may have settled into what we thought was good sound, only to discover it can get better with minimal effort!

Keep us posted.