how can spinorama csv data show with zoom possible to see diffrences in bass range better ?

[Curvature]

There are multiple reasons for the bass response to not be 100% omni polar. First is there is no truly omni polar loudspeaker. However, you also need to be aware of the spinorama measurement precisions, which affect the measurement numbers too.

For example, the determination of the acoustic center of the loudspeaker is only approximate. The driver is not a point (and it is not even flat), so its acoustic center is not well defined. The ANSI/CTA-2034 standard allows for a 5 cm shift of the vertical spin axis, with its offset to the true acoustic center being unknown.

View attachment 290235

Let's see how much a 5 cm shift of the spin axis will affect the results.

In far field, the sound pressure is proportional to 1/r, i.e. p(r) = k/r. At 1 m, if we have a perfectly aligned measurement, p(r=1) = k. If the spin axis is offset by 0.05 m, p(r=1.05) = k/(1.05).

The ratio of the measurements is: p(r=1)/p(r=1.05) = 1.05. In dB, it is 20 log10(1.05) = 0.42 dB. Therefore, within the CTA-2034 spin axis positioning tolerance, we can already expect a 0.42 dB shift without considering other sources of error.

In reality, since we don't know where the true acoustic center is, the offset can be more than 5 cm. Adding to it the other measurement errors, comparing to directivity numbers to less than 1 dB is highly problematic.

Below is my simulation of a simple front firing boxed loudspeaker at 75 Hz. (The simulation is 2D, and represents the radiation pattern of a line source.) From this simulation the acoustic center is actually in front and outside of the speaker cabinet.

View attachment 290236

I really appreciate your explanation and simulation. The LF directivity has been explored in this article as well.

 

[Curvature]

speaker + room is one system is right. so i can influence the sound with less directivity of the speaker or damp the room more. its logical when a speaker do less energy send to side direction it is better. theory say there is no diffrence in bass. but when the air of the bass move more in front (because case do less resonate maybe) and measures show there are diffrences. in test when level of reverb reduce 0.5 db can hear good

that the magnepan have a very small bass directivity is maybe because it have no case that can resonate.

You are incorrect about bass behaviour. Fundamentally incorrect. Please read some books. It is easy to use a microphone, but very hard to interpret the results.

 

[bennybbbx]

You are incorrect about bass behaviour. Fundamentally incorrect. Please read some books. It is easy to use a microphone, but very hard to interpret the results.

the spinorama data of Amirs measure have many measure points and is nearfield. The magnepan have the 2-3 db less output power on side and back on 82 hz on many frequency and angle can be sure this give less bass reverb. more values of the magnepan LRS

82 hz 77.49 db 74.06 db -3.43 db
160 hz 79.416 db 75.64 db -3.77 db
307 hz 85.716 db 81.7458 db -3.97 db

i know the room have much influence and i read books all correct and carefull and i understand and notice clear, that the reduced energy level from side can reduce room modes for bass transients mostly and have positive influence with less reverb on bass https://www.audiosciencereview.com/forum/index.php?threads/magnepan-lrs-speaker-review.16068/

please look at this magnepan test. in this test there is also a curve for the room reflections in the Near Flied SPL Response digramm. it is on bass much lower. because i see no other tests that have room reflections display, i can not compare. maybe there are more test ? . i know from my measure in bass is room reflections always much higher as on 300 hz. a bad sounding range in music is range 80-300 hz. this is much reduce in the favourite test songs to test hifi speakers btw. so let speakers sound nicer and more good sound

 

[bennybbbx]

I really appreciate your explanation and simulation. The LF directivity has been explored in this article as well.

intresting test but this is a theoretic example with a continues noise and have less to do with music. Should better test with real music transients . thats always the problem in hifi world. speaker developers ike when test their speakers with continues measure signal. thjis let look them better. but to see real world quality of speaker you need also test it with bursts. real music in bass have transients. and only if a continues signal happen over some cycles the room modes reach full strength. there is how the kick transient look https://www.idrumtune.com/12-kick-drum-tuning/ If the speaker output more on right and left then for sure because of room the kick does not sound so tight as it is in

 

[Curvature]

intresting test but this is a theoretic example with a continues noise and have less to do with music. Should better test with real music transients . thats always the problem in hifi world. speaker developers ike when test their speakers with continues measure signal. thjis let look them better. but to see real world quality of speaker you need also test it with bursts. real music in bass have transients. and only if a continues signal happen over some cycles the room modes reach full strength. there is how the kick transient look https://www.idrumtune.com/12-kick-drum-tuning/ If the speaker output more on right and left then for sure because of room the kick does not sound so tight as it is in

You are mistaken. The article has nothing to do with hifi (the context is PA) and there would have been no point in testing transients or music. The article was showing behaviour of LF in large rooms and psychoacoustic effects of directivity above 100Hz for subwoofers (as well as how to go around plotting that more usefully on graphs).

the spinorama data of Amirs measure have many measure points and is nearfield. The magnepan have the 2-3 db less output power on side and back on 82 hz on many frequency and angle can be sure this give less bass reverb. more values of the magnepan LRS

82 hz 77.49 db 74.06 db -3.43 db
160 hz 79.416 db 75.64 db -3.77 db
307 hz 85.716 db 81.7458 db -3.97 db

i know the room have much influence and i read books all correct and carefull and i understand and notice clear, that the reduced energy level from side can reduce room modes for bass transients mostly and have positive influence with less reverb on bass https://www.audiosciencereview.com/forum/index.php?threads/magnepan-lrs-speaker-review.16068/

please look at this magnepan test. in this test there is also a curve for the room reflections in the Near Flied SPL Response digramm. it is on bass much lower. because i see no other tests that have room reflections display, i can not compare. maybe there are more test ? . i know from my measure in bass is room reflections always much higher as on 300 hz. a bad sounding range in music is range 80-300 hz. this is much reduce in the favourite test songs to test hifi speakers btw. so let speakers sound nicer and more good sound

I'll explain what I can and then it's up to you to return to the books. Because it's plain that you do not understand enough.

1. Magnepan directivity: The Magnepan is a dipole speaker. The LRS specifically has two long panel drivers going from top to bottom, one responsible for LF and MF, then other for HF. There is no explicit baffle other than what those panels present and a very thin frame. Sound is radiated forwards toward the listener and backward, away from the listener. However, this forward/backward radiation wraps around the speaker and you see that as cancellation on the sides, which becomes progressively stronger the lower the frequency and the longer the wavelength. There is some evidence that dipole bass is more uniform in rooms than monopole bass, but in the end the problems are such that dipole represents marginal gains, if any. You can't switch a monopole sub with a dipole sub and expect all response problems to be fixed.
2. Amir's reviews: The graph you mean is this one. This graph appears once in a while when it is important to show the error vs. frequency of the Klippel NFS. Amir says explicitly that it's a comparison of computed vs. measured response. For the Magnepan LRS, the HF show a lot of error because the radiating panels above a certain frequency do not move uniformly across their entire surface (they complexly "break up" into multiple radiating areas). The room reflections are there to show the strength of direct vs. reflected sound for the NFS calculation. He measures speakers in a large garage and then moves them to his living room to actually listen. You cannot compare that graph to your room results.
3. "Sound" is generally 20Hz to 20kHz. However neither your hearing nor speakers nor rooms treat all the frequencies the same. Like speakers, your ear system is multiway, separated into different channels depending on frequency. You can group those channels roughly and say that above ~1.5kHz you are mostly sensitive to SPL, while below that you are mostly sensitive to time. The lower in frequency, the more time is required by your ear to lock onto the phase of the incoming soundwave. So at LF you will tolerate much more ringing than at MF or HF before finding it sounds wrong or obtrusive.
4. In acoustics there are small rooms and large rooms. The definition depends on frequency. Small rooms have dimensions smaller than LF wavelengths (<17m for wall length or ceiling height) and large rooms have dimensions larger than LF wavelengths (>17m). Large rooms have some "bass reverb" because there's enough distance for LF to travel, hit a wall and travel back, like an echo. Small rooms have no "bass reverb".
5. In small rooms, you have three regions: modal (LF), transitional (MF), statistical (HF). The Schroeder frequency refers to sound behavior, and marks the divide between the modal and statistical regions. The definition is a little loose, so the best way to think about it is that, around the frequency whose wavelength matches your room dimensions, that's the Schroeder frequency and the rough beginning of the transitional region for that room.
6. The HF response is dominated by the speaker. The speaker is in control. The response is can be predicted by directivity plots (or the composite PIR) above around 500Hz-1kHz.
7. The MF show a very complex and relatively unpredictable response that is sensitive to where you place the speakers relative to the walls, floor and ceiling, and where you sit and listen. This is the nonminimum phase region of the room.
8. The LF is dominated by the room. The speaker has limited influence on the response. This is because LF response can be mapped to room dimensions and materials. All materials pass some sound, reflect some sound, absorb some sound and flex with sound. Even brick. Every point in your room has a different response in the LF because of the very different size of wavelengths and their bounces. See here and here. The response can predicted by looking at the size and materials of your room, independent of the speaker.

There is another long explanation for how absorbers work that I've given before. Foam, fibreglass, denim are porous absorbers with severely limited effect below 200Hz. This is due to velocity vs. pressure gradients in rooms. That 80-300Hz region that you have problems with is roughly in the transitional region. People often refer to it as Speaker Boundary Interference Response (SBIR). It can be fixed with LF panel based absorbers like (1), (2), (3), (4) or this Helmholtz based absorber. SBIR cannot be fixed by changing speakers.

 

[bennybbbx]

You are mistaken. The article has nothing to do with hifi (the context is PA) and there would have been no point in testing transients or music.

bass is often percussive so testing of percusive signals in room is also important. also it seem brain can hear a low bass with only a half wave of it. in a tight kick drum the first half wave reach 0 db. the second half wave reach -12 or less db. see in above link .

1. Amir's reviews: The graph you mean is this one. This graph appears once in a while when it is important to show the error vs. frequency of the Klippel NFS. Amir says explicitly that it's a comparison of computed vs. measured response. For the Magnepan LRS, the HF show a lot of error because the radiating panels above a certain frequency do not move uniformly across their entire surface (they complexly "break up" into multiple radiating areas). The room reflections are there to show the strength of direct vs. reflected sound for the NFS calculation. He measures speakers in a large garage and then moves them to his living room to actually listen. You cannot compare that graph to your room results.

sure, i can not compare the graph with my measure. but because it is near field measure when i put a speaker with lower output at 90 degree in my room it also do lower output in general. maybe on some frequency it do more . because speakers have mostly bassreflex and if rear port or front port give also diffrences.

i have written before it is to compare the speakers. The magnepan is only a example with lots diffrent directivity. there can also enough diffrences see between other speakers at 80 hz.

1. In acoustics there are small rooms and large rooms. The definition depends on frequency. Small rooms have dimensions smaller than LF wavelengths (<17m for wall length or ceiling height) and large rooms have dimensions larger than LF wavelengths (>17m). Large rooms have some "bass reverb" because there's enough distance for LF to travel, hit a wall and travel back, like an echo. Small rooms have no "bass reverb".

I write about 80 hz this is wavelength 4.3 meter and later 160 hz . this is 2.15 meter . in this range a speaker with less directivity i think is usefull

1. In small rooms, you have three regions: modal (LF), transitional (MF), statistical (HF). The Schroeder frequency refers to sound behavior, and marks the divide between the modal and statistical regions. The definition is a little loose, so the best way to think about it is that, around the frequency whose wavelength matches your room dimensions, that's the Schroeder frequency and the rough beginning of the transitional region for that room.

it depend from speaker distance how much reverb influence. sure on large distance to speaker room sound is more influence as direct sound. in nearfield it is less.

see this table of direct sound dominance. https://www.genelec.com/correct-monitors

in hifi science all is simplified to a theoretic situation. but in real world music there are transients and the direct sound dominance is diffrent depend on speaker distance

 

[Curvature]

bass is often percussive so testing of percusive signals in room is also important. also it seem brain can hear a low bass with only a half wave of it. in a tight kick drum the first half wave reach 0 db. the second half wave reach -12 or less db. see in above link .



sure, i can not compare the graph with my measure. but because it is near field measure when i put a speaker with lower output at 90 degree in my room it also do lower output in general. maybe on some frequency it do more . because speakers have mostly bassreflex and if rear port or front port give also diffrences.

i have written before it is to compare the speakers. The magnepan is only a example with lots diffrent directivity. there can also enough diffrences see between other speakers at 80 hz.



I write about 80 hz this is wavelength 4.3 meter and later 160 hz . this is 2.15 meter . in this range a speaker with less directivity i think is usefull




it depend from speaker distance how much reverb influence. sure on large distance to speaker room sound is more influence as direct sound. in nearfield it is less.

see this table of direct sound dominance. https://www.genelec.com/correct-monitors

in hifi science all is simplified to a theoretic situation. but in real world music there are transients and the direct sound dominance is diffrent depend on speaker distance

So... I'm done. You clearly don't understand and haven't "read the books".

 

[bennybbbx]

So... I'm done. You clearly don't understand and haven't "read the books".

in the books did not stand that the directivity in bass of a speaker have no influence. you have written that

There is some evidence that dipole bass is more uniform in rooms than monopole bass, but in the end the problems are such that dipole represents marginal gains, if any.

you also write that gains are possible. as long there are no good test it is just believing. and when can see in spinorama 80 hz and lower too and compare good, then verybody can test and compare speaker in his room
the magnepan is worse because for higher freq so a large system is not usefull. also below 50 hz is a very fast drop in level. slow drop in level can brain compare. in Amirs testsong the basedrum have 35 hz levels. sure that it on a speaker with 50 hz sharp hipass sound strange.

 

[bennybbbx]

So... I'm done. You clearly don't understand and haven't "read the books".

have you read that ?

Dipole vs Monopole woofer

A dipolar source in a regular, sparsely decorated rectangular room excites mostly length modes and not width and height modes which are in the null plane of the source’s polar pattern, when the source axis is parallel to the length direction. [18]

he later write

No meaningful conclusions could be drawn from the steady-state room transfer functions about performance differences between dipolar and monopolar radiation.

but this conclusion is based on the things he tests. also a subwoofer only output lower bass as 160 hz

and his last words

The investigation showed that measurable and audible quality differences exist between monopolar and dipolar woofers due to differences in their respective interactions with the room. The degree of these differences is difficult to predict and will depend upon the specifics of a room and the placement of woofer and listener. However, the dipolar source can be expected to interact less strongly with the room and will, therefore, on average convey greater detail and resolution of complex low frequency material.

and a speaker with a rear bass port or a rear passive membrane can also give some advanatage because it work a little as a dipol

 

[dfuller]

and a speaker with a rear bass port or a rear passive membrane can also give some advanatage because it work a little as a dipol

What? No. Not at all.

Your issues with low end being messy are down to your room (20cm panels are still operating as broadband absorbers, and are near as useless below about 200hz), listening position, and speaker placement. The 5cm panels you have are just straight up useless below about 700hz.

If you want to clean that up, you need to look at placement, and to some degree, pressure traps and EQ.

 

[bennybbbx]

What? No. Not at all.

Your issues with low end being messy are down to your room (20cm panels are still operating as broadband absorbers, and are near as useless below about 200hz), listening position, and speaker placement. The 5cm panels you have are just straight up useless below about 700hz.

there are lots diffrences in damping of material. basotect at 600 hz have a damping factor of more than 0.8 (1 is maximum damp) .0.8 is 80%. this you mean useless below 700 hz ????. at 160 hz 5 cm still have 0.2 or 20% . this is also good hearable. if you double it to 10 cm it have at 100 hz 0.2 https://plastics-rubber.basf.com/gl....html#accordion_v2-fc346a041f-item-b64aa4d213 you need click on Schallabsorption to see the values

If you want to clean that up, you need to look at placement, and to some degree, pressure traps and EQ.

problem is there are no specs of basstrap or such stuff. and as usual in hifi world most is overprced vapor. I decide for basotect because it have measurements and it look nice white . if i see usefull measure results of basstraps i can buy. but i dont want spend lots money and get hifi vapor that do same result as basotect . testers should not only test speakers also test basstraps and more because room influence is alao important. basotect is wihite or light gray so look not bad in room

 

[Curvature]

there are lots diffrences in damping of material. basotect at 600 hz have a damping factor of more than 0.8 (1 is maximum damp) .0.8 is 80%. this you mean useless below 700 hz ????. at 160 hz 5 cm still have 0.2 or 20% . this is also good hearable. if you double it to 10 cm it have at 100 hz 0.2 https://plastics-rubber.basf.com/gl....html#accordion_v2-fc346a041f-item-b64aa4d213 you need click on Schallabsorption to see the values

The absorption coefficient (α) assumes a diffuse, reverberant field and random incidence of sound. In small rooms there is no diffuse field because in the statistical region you have strongly correlated and directional reflections, and in the modal region you have modes rather than individual reflections, and a mix of these in the transitional region.

α is based on absorption in Sabines for a given surface area and volume. It can be higher than 1.0 in real measurements due to diffraction and additional absorption by the sides of the material, even though the equation only takes into account the front face. α does not refer to % absorbed.

Most testing facilities are not certified below 100-200Hz, but α is used anyway since there is no other widely accepted standard.

Basotect is a velocity absorber. There is an inverse relationship between velocity and pressure. The closer you get to the wall, the higher the pressure and the lower the velocity. So the lower the frequency you want to absorb, the less effective velocity absorbers become. This why it's suggested that LF treatment works best in corners, where pressure is maximum in a room.

Numbers are meaningless without context.

All the products I listed have lab testing done.

 

[bennybbbx]

The absorption coefficient (α) assumes a diffuse, reverberant field and random incidence of sound. In small rooms there is no diffuse field because in the statistical region you have strongly correlated and directional reflections, and in the modal region you have modes rather than individual reflections, and a mix of these in the transitional region.

α is based on absorption in Sabines for a given surface area and volume. It can be higher than 1.0 in real measurements due to diffraction and additional absorption by the sides of the material, even though the equation only takes into account the front face. α does not refer to % absorbed.

Most testing facilities are not certified below 100-200Hz, but α is used anyway since there is no other widely accepted standard.

Basotect is a velocity absorber. There is an inverse relationship between velocity and pressure. The closer you get to the wall, the higher the pressure and the lower the velocity.

can you post a link where this can read form science or physican ? . logic pyhsical sound is moving air . if the air have more pressure it can reach higher velocity.
pressure and velocity is the type of absorbers.
https://hexspa.com/velocity-vs-pressure/

Velocity absorbers tend to be broadband and work over a large range of frequencies whereas pressure absorbers usually work with a more narrow range. If you’re building a home studio, you need a lot of broadband velocity absorbers and probably no pressure, also known as resonant, absorbers.

Sound Pressure

Sound Pressure is the force of sound on a surface perpendicular to the propagation of sound.

www.engineeringtoolbox.com

Sound is usually measured with microphones responding proportionally to the sound pressure. The power in a sound wave goes as the square of the pressure. (Similarly, electrical power goes as the square of the voltage.) The log of the square of x is just 2 log x, so this introduces a factor of 2 when we convert to decibels for pressures.

Sound Pressure Level (decibels)​

Numbers are meaningless without context.

there should always remeber all is relative. and that basotect foam is much better for bass as other acoustic foam i have measure myself. but you can see values of expensive acoustic foam . there is 1 inch and 2 inch wedge foam https://www.prosoundweb.com/paramet...-method-of-acoustic-treatment-second-edition/

and here is the 2 inch foam . the values look good, it is more expensive a basotect. strange on this the absorb 1.1 at high freq. never trust the audio developers https://auralex.com/content/performance/2wedgenew.pdf

All the products I listed have lab testing done..

where you have listet products that are test ?

 

[bennybbbx]

The absorption coefficient (α) assumes a diffuse, reverberant field and random incidence of sound. In small rooms there is no diffuse field because in the statistical region you have strongly correlated and directional reflections, and in the modal region you have modes rather than individual reflections, and a mix of these in the transitional region.

basotect absorbation is measure with a standard certificate method
In a reverberation room according to the international standard DIN EN ISO 354 https://www.cmfacoustics.com.au/Basotect1.pdf

more as 1 is not possible. maybe just shift the top of the measure from others. it have 1.15 max. when subtract 0.15 from the 0.2 at 125 hz it get 0.05

 

[dfuller]

there are lots diffrences in damping of material. basotect at 600 hz have a damping factor of more than 0.8 (1 is maximum damp) .0.8 is 80%. this you mean useless below 700 hz ????. at 160 hz 5 cm still have 0.2 or 20% . this is also good hearable. if you double it to 10 cm it have at 100 hz 0.2 https://plastics-rubber.basf.com/gl....html#accordion_v2-fc346a041f-item-b64aa4d213 you need click on Schallabsorption to see the values

You misunderstood this. Again.

0.2 is generally bad. Like barely better than bare wall.

Further: velocity traps don't work well right on boundaries. That's just physics, there is little velocity at a boundary. You need to have them off the wall by a fair bit for them to be effective.

Pressure traps are most effective right up on a boundary as pressure builds there.

The reason your low midrange/upper bass region sounds wrong is because your reverb times are totally out of whack. You dumped all the high end and have done nothing about the low end.

Please go read Everest's book on acoustics.

 

[Curvature]

Everest's book on acoustics

Master Handbook of Acoustics, Seventh Edition. Ken C. Pohlmann, F. Alton Everest. 2021.

Also Toole's book.

Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms, Third Edition. Floyd E. Toole. 2017.

And this fundamental book on treatment.

Acoustic Absorbers and Diffusers: Theory, Design and Application, Third Edition. Trevor Cox, Peter D’Antonio. 2016.

 

[Curvature]

speaker with a rear bass port or a rear passive membrane can also give some advanatage because it work a little as a dipol

No. Ports are like another "way" in a speaker.

have you read that ?

Dipole vs Monopole woofer

Yes. I've seen other investigations too. In his case you have a sample of two rooms only. I wouldn't say the result was perfect either. The same problems remain with dipoles: no consistency from seat to seat, position dependent response, and modal excitation (although different modes). The speech modulation measurements don't have place in the investigation because the waveform analysis is highly level and frequency sensitive (so hard to interpret), and the "informational preservation" overall comes down to frequency response.

Toole's word on the matter: https://www.audiosciencereview.com/...-without-measurement.7127/page-13#post-166829

where you have listet products that are test ?

Speaker Boundary Interference Response (SBIR). It can be fixed with LF panel based absorbers like (1), (2), (3), (4) or this Helmholtz based absorber. SBIR cannot be fixed by changing speakers.

Click the links.

 

[bennybbbx]

0.2 is generally bad. Like barely better than bare wall.

you choose the bass value. for bass this is a good value. 20% less each reflection. in 5 reflection should 0 therotic if all is damped.

here you can read values of floor ,, walls at least for 500 hz. walls have much less at 500 hz below 0.1. basotect at 500 hz have too more than 0.8 . and it is logical when at higher freq it is more it is on lower freq too more

Common Absorption Coefficients for Acoustical Treatments - Commercial Acoustics®

List of Absorption Coefficients used to determine reverberation time.

commercial-acoustics.com

Further: velocity traps don't work well right on boundaries. That's just physics, there is little velocity at a boundary. You need to have them off the wall by a fair bit for them to be effective.

that seem not logic. . the information is in the air pressure. and doesnt matter where damp. audio move 340 m/sec so in a 3.4 meter room they are 50 times reflectet for rt 60 0.5 sec

see link about soundpressure i post in this post

how can spinorama csv data show with zoom possible to see diffrences in bass range better ?

There are multiple reasons for the bass response to not be 100% omni polar. First is there is no truly omni polar loudspeaker. However, you also need to be aware of the spinorama measurement precisions, which affect the measurement numbers too. For example, the determination of the acoustic...

www.audiosciencereview.com

Pressure traps are most effective right up on a boundary as pressure builds there.

but there are no measure values how much they damp at bass freq is of such stuff. The damping in bass is in rt 60 decay realy good. only what stay in is the 80 hz boom bass boost. problem is sound also bad when i reduce with eq and it soundalways to wide in mono in compare to headphones whan play a 80 hz sine. So i think better basstraps can not help. 10 cm basotect is great in corners but it reduce near nothing in the Bass FR

 

[bennybbbx]

No. Ports are like another "way" in a speaker.

Yes. I've seen other investigations too. In his case you have a sample of two rooms only. I wouldn't say the result was perfect either. The same problems remain with dipoles: no consistency from seat to seat, position dependent response, and modal excitation (although different modes).

sure he write it is not always better, and it is unknown when it is better, but at least when see the spinorama values with more damping, there can try a speaker in the room and look if it is better or not

The speech modulation measurements don't have place in the investigation because the waveform analysis is highly level and frequency sensitive (so hard to interpret), and the "informational preservation" overall comes down to frequency response.

Toole's word on the matter: https://www.audiosciencereview.com/...-without-measurement.7127/page-13#post-166829



Click the links.

ah this links you mean. 1. link did not work and this demotivate me to click other links. but now i look. this have high values. and whats the price of it ?. problem is this have no independent testers test. with the basotect it is for more than only acoustic treating. so there is not so much need to fake nice results .

 

[Curvature]

whats the price of it ?. problem is this have no independent testers test.

Do some research! The information is right there!