RoomPhase – a room acoustics planning tool I've been developing. Looking for serious technical feedback

[RoomPhase]

Hello all,

I should probably start with what I'm not.

I'm not new to ASR but I've been a reader rather than a contributer. I'm not an acoustics engineer, mathematician or software developer. I'm a home cinema/audio enthusiast with a reasonable working knowledge of REW, Dirac and room acoustics, but there are plenty of people on this forum who know vastly more about these subjects than I do.

I've also used AI to help me develop the software, including the coding and implementation of a lot of the underlying maths.

I'm saying that upfront because I'm not here to present myself as an expert. Quite the opposite: one reason I'm posting on ASR is that I'd like people who really understand this stuff to challenge what I've built.

The project is called RoomPhase.

I originally started it for myself because I found there was a gap between understanding that I had an acoustic problem and knowing what I should actually do about it.

REW is extraordinarily powerful, but for someone who isn't an acoustic engineer it can still leave you looking at a measurement thinking: OK, I can see the problem – now what?

RoomPhase is intended to sit around that process rather than replace it.

One of my priorities from the start was that RoomPhase should also be an educational tool. A big part of this project for me has been learning the terminology and understanding what the measurements and calculations actually mean, rather than just being given a result. So wherever possible I’ve tried to make RoomPhase explain what it is showing, why it matters, what the relevant acoustic terms mean, and what the limits of the calculation or measurement are. My hope is that someone can use it not just to improve a room, but to gradually understand the acoustics behind the decisions they’re making.

You enter the physical room, speakers, subwoofers, listening positions, displays, furniture and acoustic treatment. It then combines room geometry, acoustic modelling and eventually real REW measurements to help investigate what's happening and, importantly, explain possible changes.

At the moment it includes things such as:

• 2D/3D room modelling with speaker, subwoofer and listening-position placement
• axial and tangential room-mode analysis
• frequency investigation
• first-reflection analysis
• speaker and subwoofer placement analysis
• seating/listening-position analysis
• acoustic-treatment planning
• crossover, phase, polarity and delay investigation
• REW integration
• comparison of predicted behaviour with measured behaviour
• guided recommendations rather than simply displaying graphs

A major design principle is that it shouldn't just say "move the sub here" or "add 3.6 ms delay".

It should explain why, show the evidence behind the recommendation, state the assumptions being made and, where the evidence isn't strong enough, say so.

I'm also trying hard to avoid pretending that a rectangular-room mathematical model is the real room. Prediction and measurement need to be treated as different things, and recommendations based on measurements should carry more weight than an idealised model.

For multiple subs I'm particularly interested in measurement consistency, timing references, phase interaction and properly recording the actual gain/delay/polarity/filter state under which each measurement was taken.

Longer term I'm also looking at how RoomPhase could work alongside specialist tools such as MSO rather than attempting to reinvent them.

This is still under development and I'm not asking anyone to buy anything. I'm trying to find the weak points before I get anywhere near that stage. Some areas are more mature than others and I’m still tightening the measurement workflows, validation rules and explanations. I’m deliberately showing it before I consider it finished because I’d rather have knowledgeable people challenge the methodology now than discover later that I’ve built confidence around a bad assumption.

That's really why I'm posting here.

I'd be very interested in feedback from experienced REW users, acoustics people and anyone who has spent far too many evenings moving subwoofers around a room.

In particular:

What would RoomPhase have to check, explain or show you before you'd trust it enough to actually move a sub, change a delay, alter a crossover or put acoustic treatment somewhere based on its recommendation?

And perhaps even more importantly:

What assumptions, calculations or failure modes would make you distrust it immediately?

I'm perfectly happy to be told that something is wrong. If you think a calculation, assumption or methodology doesn't stand up, I'd much rather find that out now.

I'll add some screenshots below rather than turn this first post into an enormous wall of text.

A few screen shots attached to show the current approach. Some views are predictive, some measurement-based, and RoomPhase tries to make that distinction explicit rather than blending the two.

• Room Editor.jpg
  RoomPhase builds a simplified geometric model of the actual room, including features such as the bay window and chimney breast. The model is used for modal, reflection and treatment calculations, but it is not treated as a substitute for measurement.
• Bass.jpg
  Bass analysis combines room dimensions, seat positions and subwoofer positions to show predicted modal behaviour across the listening area. The intention is to help narrow down sensible positions before validating them with REW.
• Measurements3.jpg
  This compares RoomPhase’s simplified room-model prediction against an imported REW sweep. The curves are shape-normalised rather than absolute-SPL matched. The 62% figure is a partial correlation indicator, not a claim that the room has been predicted with 62% accuracy. Individual predicted room modes are also checked against measured energy around the expected frequencies.
• reflections.jpg
  This view calculates geometric reflection paths and their arrival times relative to the direct sound. It identifies where reflections are likely to originate, but their actual strength or audibility still needs measurement. RoomPhase deliberately separates geometry from measured acoustic significance.
• Room Editor2.jpg
  RoomPhase estimates reverberation and absorption from the room geometry, surfaces, furnishings and treatment entered by the user. These are planning estimates. Where REW decay data exists, measured behaviour takes precedence.

 

[Keith_W]

Hi Daniel, good to see you here. I suggested you make a thread on ASR when I saw your post on Facebook

One thing you forgot: a link to download and try your software.

 

[RoomPhase]

Hi Keith,

Thanks. It’s not quite yet ready for beta testing. Right now I’m just asking for feedback on the questions in my post.

Daniel.

Hi Daniel, good to see you here. I suggested you make a thread on ASR when I saw your post on Facebook

One thing you forgot: a link to download and try your software.

 

[Keith_W]

As I understand it, your software is a room simulator which cross-checks its predictions against actual REW measurements. It can then identify flaws in the measurement, and make remedial suggestions.

The problem with all these predictive calculators is that the input parameters must match actual room parameters exactly. Part of the onus is on the user to take note of microphone position, microphone height, speaker position, etc. and put it into the calculator. That is out of your control, and from my experience of looking at a lot of measurements on ASR, it's not something I would trust the general user to be able to do. Many of these guys can't even read my book and follow simple instructions about how to take measurements. I guarantee they will screw it up and then blame it all on you. It would be even worse if you charged them for the software, then they would expect you to solve a problem that they themselves created.

The other part of the onus is on you to allow the user to input every room feature: concave or convex walls, openings, sloped ceilings, windows, non-parallel walls, etc. A good number of people here put their computers on their study desks, which means that elevation from the desk, computer monitors, and other nearby objects become important. Some rooms can be very complex, e.g. my current room has an opening to the dining room / kitchen and to a stairwell.

And lastly, you will need to account for the varying directivity characteristics of loudspeakers. Conventional, cardioid, dipole, or omni.

Anyway it sounds like you are writing an intriguing tool that would help a lot of people. Personally I would find it too hard which is why I just tell people to use their brains

 

[Bhavik Patel]

Many of these guys can't even read my book and follow simple instructions about how to take measurements.

Which book you are referring? Can you share it again. Sorry I am new to ASR.

 

[RoomPhase]

Thanks Keith, that’s really helpful feedback.

You’re right that the predictions will only be useful if the room and microphone details are entered correctly. That’s one of the things I need to be very careful about, because users could easily enter something incorrectly and then blame the software.

I also agree that real rooms can be much more complicated than a simple box, with openings, different wall types, sloped ceilings, furniture and different speaker designs.

At the same time, I need to be careful not to turn RoomPhase into a full architectural design tool. I’d rather focus on modelling the room features that actually make an acoustic difference, and keep the process as simple as possible.

I’m still developing RoomPhase, so I don’t want to pretend all of this is solved yet. My aim is to guide users through the measurements, make the assumptions clear, show how confident the prediction is, and compare it with real REW measurements.

Thanks again — this is exactly the kind of feedback I need.

 

[hast]

Which book you are referring? Can you share it again. Sorry I am new to ASR.

https://www.audiosciencereview.com/...eting-measurements-with-rew-free-ebook.66771/ - in his "signature"

 

[Bhavik Patel]

https://www.audiosciencereview.com/...eting-measurements-with-rew-free-ebook.66771/ - in his "signature"

Thanks for sharing

 

[RoomPhase]

A short RoomPhase development update.

A lot has changed since I first posted about the project, and over the last few days the focus has increasingly shifted from building features to trying to prove that the foundations underneath them are sound.

That distinction matters.

One of the things I’m particularly conscious of, having used AI extensively during development, is that code which looks plausible and produces plausible-looking graphs is not sufficient evidence that the acoustic model is correct.

So we’ve started a much broader technical assurance pass.

For example, the loudspeaker geometry has been consolidated around a canonical physical model covering cabinet dimensions, mounting reference, acoustic source/reference position, orientation, toe-in and vertical placement. One concern I specifically wanted checked was whether RoomPhase could draw a speaker in one position while performing the acoustic calculations from a subtly different position.

The initial audit found that particular problem was not present, which was encouraging, but the exercise has also highlighted areas of duplicated calculation logic and other things that need consolidation and more numerical testing.

The intention now is to apply the same principle much more widely:

model → analytical test → implementation test → measurement validation

That includes room modes, reflections, phase and delay, bass prediction, treatment logic, scoring/confidence and eventually the interpretation of REW measurements.

The REW workflow itself is also being tightened considerably.

For the initial beta, RoomPhase won’t rely on a live REW API connection. Users will upload measurement data instead.

The harder part isn’t importing a frequency-response graph. It’s deciding whether two measurements are genuinely comparable before RoomPhase starts drawing conclusions from them.

So the workflow needs to understand things such as measurement identity, timing reference, sweep conditions, microphone/setup changes and system state including gain, delay and polarity.

I also want it to distinguish between:

Improved
Unchanged within measurement repeatability
Worsened
Not comparable

rather than manufacturing a result when the measurements don’t justify one.

There has been quite a bit of UI work as well. Seating, displays/projector screens and more realistic room geometry are being incorporated into the Room Editor, while I’m trying hard to keep the workflow understandable for someone who knows REW and basic room acoustics without requiring them to think like an acoustics engineer.

Some of the questions raised here - mixed wall construction, open-baffle speakers, the modelling approach itself, multi-sub optimisation and, particularly, what evidence RoomPhase would need to present before someone trusted one of its recommendations — have been very useful. They’re exposing assumptions I want challenged before the beta rather than afterwards.

We’re now getting reasonably close to that beta.

The beta will initially run online, because central deployment makes rapid fixes and updates much more practical.

I haven’t, however, decided that this should necessarily be the permanent delivery model.

I’d therefore be interested in the preference of people who might actually use software like this.

A — SaaS

Software as a Service: log into RoomPhase through a browser and use the application online. No installation, and updates happen centrally, but the application depends to some extent on the online service.

B — Local browser-based

The application runs locally on your computer and uses the browser for its UI. Projects and potentially the acoustic calculations remain on the local machine rather than requiring an online service.

C — Installable application

A conventional Windows/macOS desktop application.

Assuming the acoustic features were identical, which would you actually prefer — A, B or C?

I’m also interested in the reasons, particularly privacy, reliability, offline use, updates, performance or simply whether you dislike software that requires a subscription/login.

There is still plenty to validate, and I’m deliberately resisting the temptation to call something “finished” because the UI works.

But RoomPhase is starting to reach the point where external testing will be far more useful than continuing to develop it entirely in isolation.

 

[RoomPhase]

Quick RoomPhase update — with a slightly bruised ego.

I’ve spent some time today looking properly at Home Theatre Maestro (HTM), which some of you may already know about. I hadn’t appreciated quite how far along it was.

Annoyingly, it’s very impressive.

I say “annoyingly” because I’ve been working on RoomPhase in a similar general area, and HTM already covers a lot of the ground I thought was still relatively open: room modelling, speaker placement, REW/Audyssey import, prediction vs measurement, treatment planning, reports and a very smooth real-time 3D interface. It also has a very capable free version.

So I’m going to do the sensible thing rather than pretend I haven’t seen it.

I’m going to pause, hide in a dark room for a while, mutter quietly, and think properly about where RoomPhase should go next.

My instinct is that RoomPhase probably shouldn’t try to become another broad home cinema design suite. HTM already looks strong there. The more interesting direction may be narrower: helping REW users understand what their measurements actually mean, what can and can’t be fixed, and what practical change to try next in a real, compromised room.

That may be a better fit anyway, because that was one of the reasons I started building RoomPhase in the first place.

So this is not me abandoning it. It’s me taking a breath and avoiding the classic mistake of building something just because I’ve already started.

If anyone here has used HTM properly, especially with real REW measurements, I’d be interested in your views. Where does it work well? Where does it still leave you unsure what to do next? And is there still a useful place for a more guided measurement-interpretation tool alongside REW?

 

[Vuki]

In early 2000s ELAC made CARA room acoustics software. It offered room acoustics analysis, speaker & lp optimization etc. Great software.