Is there a Room Sim out that output a whole impulse so can see RT60 Clarity or REW can easy output a impulse ?

[user44455555]

I see in REW the room sim can generate a FR. But there can not see RT60 or clarity values. I think have such a room is usefull because then can see, what happen in small rooms with a "perfect speaker". for example you can add your room size and depend on room treatment you can add damping values. then can see if the measures match what the room sim tell with simular placing. And if the bass range you measure with clarity or RT60 T30 is noticable more worse in your measure(in compare to mid and high frequency) than in your calculation is a big sign that your speaker itself have worse case resonances, which get more influence in small rooms than in large rooms

 

[John Mulcahy]

Cabinet resonances are very short duration and have very low amplitude, they make no measurable contribution to RT60. Ported speakers have a port resonance (that's the purpose of the port).

 

[user44455555]

Cabinet resonances are very short duration and have very low amplitude, they make no measurable contribution to RT60. Ported speakers have a port resonance (that's the purpose of the port).

thats theory but nobody test for case resonances in bass range good enough. on audio science is only show a 4 ms waterfall. this is focal alpha 65 evo https://www.audiosciencereview.com/...cal-alpha-65-evo-review-studio-monitor.28832/ for the JBL 104 is no waterfall . there can not good compare speakers with that 4 ms waterfall.

another theory can be maybe speaker case itself do reflections in the room which make decay in bass worse. but i test on diffrent distance and room positions, the speakers always have resonance on near same FR
. I also test the focal with close port also worse resonances ~ 200 hz

I also test what happen when i measure the left focal and have a d3v which do nothing on right speaker stand. results can see here. FR near same but for example model fit at 52 hz when on both stative is focal is much worser. 6.3 . when measure focal on left stative and on right stative is d3v(play nothing), model fit is 2.7.
it is not much diffrence in t60m except at 60 hz. the d3v is btw worser in decay at 60 hz maybe because of 2 passive woofer. but the most important for mud is the 200 hz resonance. this let many music sound very worse and play a sine tone at this frequency on focal also sound very worse and mud and diffuse(can not locate where it comes). with my small speakers no problem

you can tell what you think, i am open to criticism if i measure wrong and what i should measure more ?. should i measure all speakers from back or side in nearfield to see if there diffrences in room interaction between speakers ?

I have upload the measures too. when i replace the focal with the d3v on right stand, i do nothing change on stative speaker or room position. other measures i do that are delay more than 20 min between measure are not exact same microphone position. I have a marker on desktop for middle and put the microphone so it is on middle when i look from top and it is position where the desktop plate begin. thats 5 cm before hearing position, but i can locate the position better for better repeat quality.

this is when on left and right stative is focal alpha 65 evo and left is measure, right do nothing play

this is when measure the focal on left and the focal on right is replace with a d3v in this measure . the right speakers do nothing play. it is only to test if the case of speaker have much or less influence .

 

[ddude003]

I guess I don't understand the fixation on RT60 when most rooms fit into the "small domestic" room category... Are you measuring a theater or a large hall???

 

[user44455555]

I guess I don't understand the fixation on RT60 when most rooms fit into the "small domestic" room category... Are you measuring a theater or a large hall???

decay time happen on all rooms. so to see really diffrences there should be also a simulation that can calc reverb for small rooms IR. there are some reverbs in which you can add room size and it can calc the reverb. such a impulse you can load into REW and see rt 60 values. but i did not find a reverb that allow sound source placement and microphone placement. maybe there is some ?

today i ask the AI. it suggest and write this explain

Most consumer and studio loudspeakers have a mechanical and electrical decay time (driver ringing, enclosure resonances, port resonances) that is significantly longer than the actual acoustic decay of a damped small room. When audio experts try to measure a small room, they are often unknowingly measuring the decay of the speaker itself, leading to the false conclusion that "the room decay is erratic and unmeasurable."
To prove this, we can isolate the variables using geometric room acoustics simulation. If we use the Allen & Berkley Image Source Method (which is implemented in toolkits like pyroomacoustics), we can input exact room dimensions (Width, Height, Depth) and precise 3D X/Y/Z coordinates for an omnidirectional source and receiver.
What the simulation shows:

1. With an Ideal Source (Delta Function): The simulator calculates the geometric reflections and energy dissipation over time. Even in a tiny room, the impulse response (RIR) shows a distinct, mathematically clean decay curve. It is perfectly measurable because the source stops radiating energy instantly (0 ms decay).
2. With a Real-World Source: If we convolve that perfect room impulse response with the actual impulse response of a real-world loudspeaker (which includes its independent decay/ringing), the speaker's own resonance completely masks the early room decay.

Because a simulation allows us to use an ideal, zero-resonance source, it proves that the room's physical energy decay is absolutely real and measurable. The limitation we face in the real world is hardware-based, not physics-based.
With modern DSP, we could theoretically inverse-filter the loudspeaker's own decay to reveal the true underlying room decay. Would it be possible to implement a feature or look into a method within REW that helps separate or window out the known transducer decay from the room's response at low frequencies?

edit and this library can also calculate non rectangle rooms the google AI tell
The takeaway for our decay discussion:
By using a Python library like pyroomacoustics in Ray Tracing mode, we can generate a highly accurate Room Impulse Response (RIR) for literally any room shape—including L-rooms and attic spaces.
When you export this simulated impulse response into a .wav file and load it into REW, it will show you the mathematically true decay time of that specific geometry. Because the simulation uses an idealized, zero-resonance impulse source, the resulting T30 or EDT curves will be clean and linear.
This will serve as the ultimate proof: complex rooms and small spaces do have a structurally cohesive, predictable decay rate. The messy, erratic decay curves we see in real-world measurements are a byproduct of real-world speaker transducers (like cabinet resonances or passive radiators ringing), not an inherent unmeasurability of the room itself.

 

[John Mulcahy]

That's nonsense, artificially intelligent but genuinely ignorant. RT60 is inappropriate in environments and at frequencies where there isn't a diffuse field. That's because the definition of the RT60 decay rests on the assumption of a diffuse field, which leads to uniform logarithmic decays which allow the linear fits to the Schroeder integral for the T20, T30 etc. decay measures. Those decays remain uniform across octave bands in a diffuse field so can provide meaningful results. In smaller spaces or in coupled spaces that assumption no longer holds. In the small space situation the modal density is so low that the decay is dominated by the behaviour of the individual modal resonances. It is easy to see them, that's what the waterfall shows and what the RT60 decay graph shows when used with a high frequency resolution.

Your assumption that panel resonances are a factor is wrong, even the flimsiest enclosures are not physically capable of supporting low frequency resonances.

Simulators that accept a room volume use Sabine's formula to estimate RT60 based on the surface absorptions, that formula also assumes a diffuse field. REW's room simulator already solves the wave equation for the entered data and produces the correct result.

 

[user44455555]

Your assumption that panel resonances are a factor is wrong, even the flimsiest enclosures are not physically capable of supporting low frequency resonances.

but wy every of my speakers bring much diffrent decay results in compare to other speakers ?. If a room have a more diffuse field or modal resonances is technical . Only what want know how, the decay is on hearing position. and here the biggest speaker focal, sound always worse .decay time at 200-300 hz is much longer as with other speakers.

the EDT of the 2 large speakers are kali LP6 and focal alpha 64 evo are over 600 ms. the JBL 104 have only 300 ms. I get repeatable such results also on other speaker and microphone positions. so what can be the reason you think ?

the mdat is attach. in previous files i have only m2 17 of my room add. but it is 34 in m3. I dont know for what the number is, it seem change nothing in results. I only use 3 speakers so it it is easier to see. the whoole mdat is attach

only the T20 look not so much diffrent. but here too the smallest speaker (JBL 104) is the best. it have very roundet case in compare to other

 

[John Mulcahy]

but wy every of my speakers bring much diffrent decay results in compare to other speakers ?

Because they have different frequency responses, different driver heights, different port positions and different port tunings so they excite the room's resonances differently.

If a room have a more diffuse field or modal resonances is technical

No, it is not. If you don't have a diffuse field small differences in how the room is driven can cause large differences in decay because how each individual mode is excited has a very storng influence.

the EDT of the 2 large speakers are kali LP6 and focal alpha 64 evo are over 600 ms. the JBL 104 have only 300 ms.

Those figures are completely meaningless, EDT is not valid for the room size and frequencies you are looking at. That's why the figures are in italics.

In-room decay times are not a meaningful way to compare loudspeakers. Why do you think anechoic chambers are used for speaker measurement, or systems like Klippel's that can eliminate room contributions and produce pseudo-anechoic results?