HTM (Home Theater Maestro) : room-acoustics modelling tool

[Paffi]

- Speaker Placement, 7.1.4: Auto Placement puts LS and RS not at the same position - LS is placed totally different way behind the listening spot
- Saving & Restoring: restoring doesn´t work
- Screen Placement: there are issues placing the screen in front of the speakers. Adjusting distance to wall adjusts the speakers as well, when you reach or want to overstep the distance of the front speakers to the wall, so that the screen is not before the speakers. Recommendation of screen dimensions varies somehow and is not always consistent, as well as the calculation of the SBIR frequency. This part of the tool (seats & screen) seems somehow buggy. Why are there two options for screen sides / angles with recommendations (smpte, thx, recommended), at "seats" and at "screen" with not corresponding values? In my case there are recommendation at "seats" and recommendation at "screen", It´s confusing for me.

 

[patoulol]

- Speaker Placement, 7.1.4: Auto Placement puts LS and RS not at the same position - LS is placed totally different way behind the listening spot
- Saving & Restoring: restoring doesn´t work
- Screen Placement: there are issues placing the screen in front of the speakers. Adjusting distance to wall adjusts the speakers as well, when you reach or want to overstep the distance of the front speakers to the wall, so that the screen is not before the speakers. Recommendation of screen dimensions varies somehow and is not always consistent, as well as the calculation of the SBIR frequency. This part of the tool (seats & screen) seems somehow buggy. Why are there two options for screen sides / angles with recommendations (smpte, thx, recommended), at "seats" and at "screen" with not corresponding values? In my case there are recommendation at "seats" and recommendation at "screen", It´s confusing for me.

Thanks a lot for taking the time to really push the tool and write all this up. A 7.1.4 with real edge cases is exactly the kind of testing that helps us improve HTM.

Let me go through your points.

Speaker placement, 7.1.4
LS and RS should definitely be mirrored. LS being placed much further behind the listening position isn’t expected. Rather than trying to guess what’s happening, we’d really like to look at your actual project. If you go to Settings → About → Contact Support, you can tick the option to attach the project. Or you can export the .htmp file from Settings → Data and send it to [email protected]. With the project, we should be able to see exactly what’s happening.

Saving & restoring
That shouldn’t happen either. If you can send us the project, and ideally let us know what you did before trying to restore it, we can reproduce it with your data and investigate it properly. Save and restore is obviously an important part of the workflow, so we want to make sure it behaves reliably.

Screen placement
Some of what you’re seeing is intentional. With an acoustically transparent screen, the front speakers are supposed to remain behind the screen. That’s why, when you move the screen backwards, HTM moves the speakers with it rather than allowing the screen to end up in front of them.

The SBIR frequency changing as the speakers move is also expected, since it is directly related to the speaker-to-wall distance.

For the screen dimensions and the Seats vs Screen recommendations, I understand why this feels confusing. They are intended to approach the same geometry from two different perspectives. “Seats” looks at the viewing angle from the listening position, while “Screen” works from a target viewing angle towards the corresponding screen size.

The SMPTE, THX and recommended values are therefore not meant to be two independent recommendations, but the way they are currently presented could make that relationship clearer. We’ll review this part of the interface and make the relationship between the two views more explicit.

If you can send us the project file, it would be really useful for checking the placement and restore issues on exactly the setup where you’re seeing them.

And thanks again for taking the time to test HTM this thoroughly. This kind of feedback is genuinely valuable for us.

 

[Paffi]

I will send you the file in the next days. Thank you for this tool - I'm comparing it to a setup made with extensive (and I mean extensive xD) use of claude opus, feeded with different setup guides (dolby, trinnov, one4all) as a basis. It's fun to experiment.

Screen placement
Some of what you’re seeing is intentional. With an acoustically transparent screen, the front speakers are supposed to remain behind the screen. That’s why, when you move the screen backwards, HTM moves the speakers with it rather than allowing the screen to end up in front of them.

Yes, I meant it the other way around. Trying to pull the screen closer to the listening spot, before the speaker, is quite hard. When I try to enter a distance further away from the wall, than the speakers - to place the screen before the speakers - it moves the speakers as well. Somehow, accidentially by clicking around in the menus, I got it before the speakers, but then lost it again...

The SBIR frequency changing as the speakers move is also expected, since it is directly related to the speaker-to-wall distance.

I meant, that the SBIR at some point didn't change at all. Somewhere >1 meter distance to the wall, while stile working for narrower distances, but stopped calculating for greater distances. Seemed buggy, because in the beginning it was working.


Did you think of adding active bass absorption? I use psi avaas, but could only find passive absorption.

 

[patoulol]

I will send you the file in the next days. Thank you for this tool - I'm comparing it to a setup made with extensive (and I mean extensive xD) use of claude opus, feeded with different setup guides (dolby, trinnov, one4all) as a basis. It's fun to experiment.


Yes, I meant it the other way around. Trying to pull the screen closer to the listening spot, before the speaker, is quite hard. When I try to enter a distance further away from the wall, than the speakers - to place the screen before the speakers - it moves the speakers as well. Somehow, accidentially by clicking around in the menus, I got it before the speakers, but then lost it again...


I meant, that the SBIR at some point didn't change at all. Somewhere >1 meter distance to the wall, while stile working for narrower distances, but stopped calculating for greater distances. Seemed buggy, because in the beginning it was working.


Did you think of adding active bass absorption? I use psi avaas, but could only find passive absorption.

Great, thanks. The project file will be exactly what we need to get to the bottom of the surround placement and restore issue.
No rush at all, whenever you have a minute:

Settings → About → Contact Support, then tick “attach my project”.

And yes, comparing HTM with a setup built using Claude Opus and fed with the Dolby, Trinnov and One4All guides is actually a pretty fun benchmark. Let us know how the two approaches compare

Regarding SBIR, what you saw isn’t really the maths stopping, but a deliberate cutoff. HTM stops showing the front wall SBIR null once the speaker is far enough from the wall that the null moves down into the deep bass. Past around 1 m, the effect is already significantly reduced, with the null below roughly 86 Hz. Beyond 2 m, we stop displaying it because at that point the dip is below roughly 40 Hz and behaves more like a room mode issue than boundary interference

It’s a defensible choice, but you’re right that from the user’s perspective it just looks like the calculation has stopped. We’ll make that clearer, and we’re also looking at extending the range for setups like yours where the screen and speakers are positioned well into the room

Regarding placing the screen in front of the speakers, with an acoustically transparent screen the front speakers are normally supposed to remain behind the screen. That’s why HTM keeps them behind the screen and moves them with it rather than allowing the screen to cross in front of them

That behaviour is intentional for an acoustically transparent screen, but we understand that it becomes frustrating when you want to place the screen in front of speakers whose position is fixed. We’re looking at a cleaner way to handle that case

As for active bass absorption, such as AVAA, that’s an interesting idea. HTM is deliberately a predictive tool based on modelling and measurement imports. It doesn’t drive or process any audio signal. However, modelling the effect of an active bass absorber alongside passive bass traps is something we can consider for a future version

No promises on timing yet, but it’s definitely noted

 

[patoulol]

Here’s a testimonial from Nicolas, a mastering engineer who used HTM while redesigning his monitoring setup and optimizing his studio acoustics.

Testimonials · Home Theater Maestro

HTM users explain how the software helped them design their private cinema, predictions in hand.

hometheatermaestro.fr

He used HTM to model the room, evaluate treatment options and identify first-reflection points without over-treating the space. The RT60 prediction also helped him anticipate the effect of the planned treatment.

Interestingly, HTM predicted an SBIR issue around 160 Hz, which he later found in his actual REW measurements and corrected with DSP.

For him, the ability to compare HTM’s predictions with real-world REW measurements was one of the most useful aspects of the software.

“Beyond simulation, HTM brings a real working methodology.”
— Nicolas, mastering engineer

 

[DTSman]

Hello,

Next HTM release will include big imrpovements of the 3D rendering. For instance catalogue for speakers, seat, sofas, ambient light and many other features.

Coming soon

 

[patoulol]

Home Theater Maestro 2.0.0 is now available.

https://hometheatermaestro.fr/?s=asr

This is our biggest update so far:

- A rebuilt 3D view, with materials, shadows and a person at the listening position
- Ambient lighting: LED strips, starry sky, spots and wall lights, to see the room as it will look during a screening
- Cut views by height or depth, and an automatic 360° tour of the room
- and many other features

The Standard level remains free, with no time limit, to design your room. HTM Pro adds full acoustic prediction, treatment planning, EQ and detailed video calibration.
Available on Windows (also on the Microsoft Store), macOS, Linux and Android


.

 

[Imakeller]

This is getting really good. Thanks for the continued improvements. Is the HTM Pro version available to the USA yet?

 

[DTSman]

A full walkthrough of HTM 2.0.0, for those who asked what a complete design looks like: an attic home cinema built from scratch. Roof frame, 19 speakers in 11.4.4 mounted on the beams, acoustic treatment, leds... The video is chaptered, so you can jump straight to the speakers or the treatment part.

The app: hometheatermaestro.fr

 

[DTSman]

This is getting really good. Thanks for the continued improvements. Is the HTM Pro version available to the USA yet?

thanks for the interest. US availability is in the works, but it will likely take a few more weeks before we decide to open it. We will update this thread as soon as it's live.

 

[DTSman]

New small video:

 

[DTSman]

New tutorial video

A full walkthrough of a polygonal attic room built in HTM. Please be indulgent with my french accent