VituixCAD v2

[tktran]

This is wonderful wisdom.

The more I get into this hobby "I know that I know nothing”

When I observe and follow people who have been doing measurements AND listening for many years or decades, it’s clear that there is a lot learnt, but also lots to learn.

These days I prefer to listen to the subjectivist objectivists.

Roughly right. Problem is that everyone can and will make own subjective interpretation what is good relative level and shape of each response in spinorama because there is no "ideal" or "optimum". Just coarse guidelines specified by investigators with their experience (limited or not), studies, used products, listening environment and setup.



Hopefully authors on ASR would also have a bit better understanding.



Room acoustics and listening setup are usually more important than features of the speakers assuming that speakers are good. I'm keen to minimize problems in many features so naming of main roles is not easy or pleasant. Few basic items: smooth/flat response to reference axis, smooth power response with proper tilt, short excess GD down to bass range, compression spectrum compatible with music, total directivity compatible with room acoustics and desired listening setup/distance, low coloration/resonances at MF-HF, low non-linear distortion. In addition there are some features which are difficult to explain with measurements. For example horn with Ti compression driver. Problem for me is probably some toxic combination of compression spectrum, mechanical features of driver and shape and material of horn. Result is probably unacceptable for me no matter how perfect spinorama looks. So finally quality of drivers and other components evaluated subjectively by ears and brain could be more important than close to perfect spinorama.

[kimmosto]

However when setting virtual mic distance; the minimum is 2200 mm.

That limit was done to prevent crash with mic when rotated >= 90 deg. Large IEC baffle is close to IB to short distances, but you can download and install the latest build manually to see how close. I have modified the latest build of 2.0.74.2 to limit off-axis angles instead of axial distance.

2.0.74.2 (2021-06-27)

Diffraction
* Added 'Baffle changed. Do you want to save?' to form closing.
* Off-axis angles limited within -90...+90 deg if axial distance is shorter than distance from origin to farthest corner of the baffle.

Calculate T/S parameters
* Randomizes initial extended Z model values within quite wide range max. 19 times to get decent result at once.

[tktran]

I'm sorry it this is FAQ #438, but what would it take to see the changes in the frequency and phase response in real time as the drivers are moved around on the baffle, with the multi-way crossover in place?

[kimmosto]

^Simultaneous diffraction and crossover simulation is not possible. Recommended design procedure is that baffle/enclosure is designed and built before crossover simulation: Checklist for designing a loudspeaker in user manual. Target is to design excellent baffle and enclosure without including external variables such as crossover. Crossover is able to compensate some weaknesses in baffled multi-way, but primarily those weaknesses should be minimized beforehand to minimize need to fix them with crossover. So design driver+baffle first so that it has smooth axial, off-axis and DI spectrum, and DI supports estimated crossover frequencies to avoid DI bump at XO with phase matched LP/HP slopes.

[tktran]

So design driver+baffle first so that it has smooth axial, off-axis and DI spectrum, and DI supports estimated crossover frequencies to avoid DI bump at XO with phase matched LP/HP slopes.

This is the process I’ve been using. But suppose one doesn’t have measurements (no datasheet or driver TBA) how does one choose an optimal baffle dimension, exact driver placement and centre to centre distance without know the driver and intended crossover in advance?

Is there a universal ideal baffle? Or is it generally a trial and error or iterative process or is there some rules of thumb or technique? Or based on combination of aesthetic preferences big roundover or facetted edges and hope for the best?

eg. MT CTC distance- mid FR not available (OEM driver)
WMTMW; but maybe change mind later for WWMTM (for portability)
WMT vs W/MT (studio monitor)- what happens when you rotate the MT sub-baffle 90 degrees?

Is it impossible due to CPU(GPU) requirements or because of the way the program/routines are separated?

[kimmosto]

...big roundover or facetted edges and hope for the best?

That is the best policy so no need to hope anything. Simple simulators such as Diffraction tool can't simulate facets so use akabak or just build, measure and design XO. That's what I do.
Main purposes of diffaction tool are to simulate baffle step for near->far field conversion of LF radiator and estimate minimum edge rounding for HF radiator. Secondary task is to design placement of HF drivers if target is bad design such as not the smallest possible shoe box with sharp edges.

Rule of thumb for c-c is 1.2 x wave length at estimated XO frequency assuming phase matched XO. This could turn to iterative process if estimation of XO frequency fails radically. Usually it's not that difficult due to response and distortion limits of raw drivers.

[kimmosto]

Is it impossible due to CPU(GPU) requirements or because of the way the program/routines are separated?

We cannot simulate accurate axial and off-axis responses of actual drivers so no use to dream about simulation of whole system before purchasing components and building at least a prototype. Enclosure shapes with good diffraction features have been known for several decades (since H Olson). The first construction is not necessarily the best possible - but as already mentioned, XO filter is able to compensate some issues, and minor directivity issues cannot override significance of driver quality and compatibility with other drivers and acoustical concept.

[Mogens20]

Rule of thumb for c-c is 1.2 x wave length at estimated XO frequency assuming phase matched XO.

Hi Kimmo, Can you please provide detail about how this rule of thumb was calculated? Is there a published paper (AES?) containing the details?

Thank you for all your efforts to create this amazing software !

[kimmosto]

^Rule of thumb can be created e.g. by optimizing Y mm of drivers with desired parameters/assumptions. For example 1.20 x WL @XO is based on following conditions:
- target is to maintain directivity at XO range - not to increase intentionally with lobing.
- c-c is not possible to be less than 1/3 x WL @XO. That is possible for W+M and S+W so c-c can be 1/4 x WL @XO or less.
- c-c is for MT at ca. listening elevation.
- XO slopes are acoustical LR4; phase matched 4th order.
- c-c is optimized by minimizing error in predicted in-room response of CTA-2034-A. This includes both sound power response and early reflections response with the same weighting factor. Simulated radiators are omni.

Optimizing produces c-c = 165.4 mm = 1.2 x WL @XO:

[kimmosto]

This one has c-c about 1.14 x WL @XO. The first edges of facets are rounded ~R30 mm. Three prototypes were made with the same c-c but different tweeter. XO designed with VCAD. To production without a single change.

Taipuu Speakers Kero

[Mogens20]

Hi Kimmo,

Thank you for your detailed reply and examples. This is very helpful.

I read through CTA-2034A and found details about equipment, setup, measuring, processing, reporting and examples of data but not I did not find a target for predicted in-room response.

Is the CC<= 1.2 X WL @ XO ROT based on the Harman in-room response target?

[Mogens20]

When I try this at 100Hz with ref axis on upper driver, here is my result. My sim was the same as yours for 2500Hz and ref axis between drivers. This example is close to, for example, woofer at bottom of cabinet with mid at top of cabinet. Maybe I did something wrong. Your software makes is so easy to simulate these scenarios. It's great!

[kimmosto]

Is the CC<= 1.2 X WL @ XO ROT based on the Harman in-room response target?

No. Just error in predicted in-room response caused by vertical directivity of two drivers at XO range.

[kimmosto]

When I try this at 100Hz

Why 100 Hz? This was for MT i.e. mid and tweeter. Not for S+W or W+M.

My spec. was c-c = 1.2 x WL @XO. Should be at least 1.0 x WL because e.g. c-c = 0.5-0.7 x wave length is the worst case scenario causing massive power and ER dip at XO range with phase matched XO. Imitate my example exactly and then go down to 1500 Hz to stay XOs for M+T. That should be c-c = 1.2 x 344000 / 1500 = 275 mm. Reduce down to 1.0 x WL if 275 mm looks ridiculous.

[Mogens20]

No. Just error in predicted in-room response caused by vertical directivity of two drivers at XO range.

I was under the impression that the error is a function of the difference between the target and prediction.

The VituixCAD help file says "Optimizer adjusts selected filter parameters/component values to shape total axial response or listening window and power response or predicted in-room response, or driver's axial response or transfer function magnitude at driver terminals to target specified by user."

What in-room response target is being specified when the CC<= 1.2 X WL @ XO ROT is being confirmed?

[Mogens20]

Why 100 Hz? This was for MT i.e. mid and tweeter. Not for S+W or W+M.

My spec. was c-c = 1.2 x WL @XO. Should be at least 1.0 x WL because e.g. c-c = 0.5-0.7 x wave length is the worst case scenario causing massive power and ER dip at XO range with phase matched XO. Imitate my example exactly and then go down to 1500 Hz to stay XOs for M+T. That should be c-c = 1.2 x 344000 / 1500 = 275 mm. Reduce down to 1.0 x WL if 275 mm looks ridiculous.

Thank you for the clarification. My apologies for assuming this ROT was for any two drivers crossing over to each other.

[Efalegalo]

Maybe I did something wrong.!

[ATTACH=CONFIG]31340[/ATTACH]

Is your driver center to center distance really 4.116 m ---> meters? That would be an awfully tall speaker, no?

[kimmosto]

What in-room response target is being specified when the CC<= 1.2 X WL @ XO ROT is being confirmed?

Default frequency response (if no frd/txt files loaded) is flat omni to every direction so everything: on-axis, off-axis, predicted in-room, power, ER, DI and ERDI responses are flat with single driver and multiple co-axial drivers. Therefore target must be flat (=default) to minimize error due to vertical lobing of separate drivers.

[kimmosto]

My apologies for assuming this ROT was for any two drivers crossing over to each other.

Wave length matters - not the name of driver. c-c should be 1/4 wave length or less if possible when target is to maintain directivity over XO range. 1/4 WL is usually not possible at HF with separate non-coaxial drivers so proper strategy (1.2 x WL @XO) is needed to minimize problems in power response and early reflections response to maintain sound balance over XO range.

Different strategy is needed if we're creating = increasing directivity with multiple drivers for the same frequency range. For example with SWMTMWS, WWMTMWW, SWCWS etc. concepts. Then c-c of each driver pair could be 0.6 x WL at the middle it's frequency range to maximize vertical directivity between XO frequencies, and c-c between M and T could also be 0.6 x WL @XO frequency. Result is almost extreme vertical directivity at midrange. That requires e.g. horn or planar/ribbon tweeter to maintain sound balance between MF and HF.

[Mogens20]

Is your driver center to center distance really 4.116 m ---> meters? That would be an awfully tall speaker, no?

Very tall! :lol: I would never locate a woofer in that position or build such a cabinet. This number represents the limit using the C-C = 1.2 x WL @100Hz strictly to observe the effect on the off-axis frequency response.

[Reet]

At 100Hz directivity should be the least of your concerns.

[Nil L]

kimmosto hello. Questions about the electrical circuit. At what frequency should the elements of the electrical circuit be measured? At 1 kHz? For example, if the inductor is a first order filter, its operating frequency is about 100 Hz. And the 3.9 uF capacitor, which works with the tweeter, has an operating frequency of more than 1 kHz.

[kimmosto]

^At frequency of your LCR meter Closest to nominal frequency of destination circuit if frequency is selectable and decent accuracy achievable.

[kimmosto]

2.0.74.4 (2021-07-04)
Optimizer
* Added quasi 5th and 7th order Linkwitz-Riley HP/LP target slopes.

2.0.74.3 (2021-06-27)
Optimizer
* Added quasi 3rd order Linkwitz-Riley HP/LP target slopes.

Basic idea of quasi/odd order Linkwitz-Riley target slopes is to offer useful targets for phase matched odd order filters. In practice those three could be more valuable than any Butterworth or Bessel targets because phase matching at XO range is much more common than phase mismatch of 90 degrees or so. Phase match with odd order is not that difficult in practice also with IIR filters because acoustical centers of different drivers are usually not at the same distance from listening point. For example when acoustical center of woofer is further than tweeter's, delay of woofer could match phase at XO range so that acoustical LR3, LR5 or LR7 could produce close to flat magnitude sum towards listening point.

Technical details about quasi/odd order L-R targets as fc=1000 Hz

[Nil L]

^At frequency of your LCR meter

My LCR meter has 120Hz and 1000Hz for measurements. Then 3-7mH inductors should be measured at 100Hz(for XO 90-170 Hz)? And 0.3-0.5 mH at 1 kHz(for XO 3-4 kHz)?

[JonMarsh]

2.0.74.4 (2021-07-04)
Optimizer
* Added quasi 5th and 7th order Linkwitz-Riley HP/LP target slopes.

2.0.74.3 (2021-06-27)
Optimizer
* Added quasi 3rd order Linkwitz-Riley HP/LP target slopes.

Basic idea of quasi/odd order Linkwitz-Riley target slopes is to offer useful targets for phase matched odd order filters. In practice those three could be more valuable than any Butterworth or Bessel targets because phase matching at XO range is much more common than phase mismatch of 90 degrees or so. Phase match with odd order is not that difficult in practice also with IIR filters because acoustical centers of different drivers are usually not at the same distance from listening point. For example when acoustical center of woofer is further than tweeter's, delay of woofer could match phase at XO range so that acoustical LR3, LR5 or LR7 could produce close to flat magnitude sum towards listening point.

Technical details about quasi/odd order L-R targets as fc=1000 Hz

Exactly! This is what I used many years ago for the NatalieP, and more recently the Isiris and Wavecor Ardent. I didn't know then that anyone had conceptualized a quasi 3rd or 5th order LR crossover, but for a given frequency matching up with the phase shift from driver acoustic origin (like a 7" woofer versus a flush on the baffle tweeter, the time offset corrects the phase problem with the network.

[kimmosto]

I didn't know then that anyone had conceptualized a quasi 3rd or 5th order LR crossover

It's probably common that designer plays with passive network until phase match and magnitude sum are okay. I have done that too especially with passive speakers. Target slopes are not necessarily available/visible so difficult to know what acoustical orders actually are and are slopes symmetrical or not. Result matters so who cares about academic details.

I haven't found any "official" concept/paper for quasi/odd order L-R. Few individuals have calculated or iterated corner frequencies and Q factors producing flat magnitude sum assuming perfect phase match. Just like factors in VCAD. They are iterated with VituixCAD, and probably different than in LspCAD where factors are also hidden inside the program and not published in user manual.

[tktran]

2.0.74.4 (2021-07-04)
Optimizer
* Added quasi 5th and 7th order Linkwitz-Riley HP/LP target slopes.

2.0.74.3 (2021-06-27)
Optimizer
* Added quasi 3rd order Linkwitz-Riley HP/LP target slopes.

Basic idea of quasi/odd order Linkwitz-Riley target slopes is to offer useful targets for phase matched odd order filters. In practice those three could be more valuable than any Butterworth or Bessel targets because phase matching at XO range is much more common than phase mismatch of 90 degrees or so. Phase match with odd order is not that difficult in practice also with IIR filters because acoustical centers of different drivers are usually not at the same distance from listening point. For example when acoustical center of woofer is further than tweeter's, delay of woofer could match phase at XO range so that acoustical LR3, LR5 or LR7 could produce close to flat magnitude sum towards listening point.

Technical details about quasi/odd order L-R targets as fc=1000 Hz

My crossover theory is not up to scratch (yet); but is this similar to:

http://www.t-linespeakers.org/tech/filters/Jeff/index.html

Jeff calls it
Asymmetrical Quasi 4th Order Linkwitz — Riley Crossover

[kimmosto]

^Yes, low pass for woofer is acoustic 3rd order "L-R" + delay by Z offset, and high pass for tweeter is acoustic 4th order L-R. That has been very common approach for at least four decades. Almost all passive diy design I've seen and built since the beginning of 80s' has been like that. Any name was not needed back then. Just working approach.

[kimmosto]

Rev. 2.0.75.0 (2021-07-20)

Main
* Added calculation of predicted preference rating. File->View->Preference rating.

Optimizer
* Added maximizing of Preference rating.
Note! Second equation (10) is better for optimizer because includes flat target for on-axis response. First equation (9) could run responses to bunker if LF extension or smoothness or both improve by tilting axial.

Implementation is modified from Olive's patent application, and might not be final. I'm waiting few comments and answers from ASR/Olive and MZKM, but threshold to start communication with me could be quite high. I have severe difficulties to accept scoring with few amplitude response groups.
Existing model for predicting preference rating doesn't provide much new if designer knows how to balance on-axis or LW and PIR or SP.

[Reet]

Great, more acronyms to learn! At least there is plain english when you hover over the column titles.

Interesting Addition to the program. I'll have to read through the patent document, but I assume in simple terms that the rating is a value from 0 to 10 where 0 is very poor and 10 is very good? Usually I would measure a speaker without including port response as it doesn't affect the crossover design, but it looks like it will definitely affect the preference rating from LFX and LFQ variables. I would assume the math changes "with sub" are intended to remove the low frequency interaction from the equation?

[Reet]

Inclusion of these descriptions, either in the help file or in the hover tool tip would be helpful. One shouldn't have to study a patent to determine what the program is doing.

AAD - Absolute Average Deviation (dB) relative to mean level between 200-400 Hz
NBD - Average Narrow Band Deviation (dB) in each 1/2 octave band from 100Hz - 12kHz
SM - Smoothness (r^2) in amplitude response based on a linear regression line through 100Hz - 16kHz
SL - Slope of Best Fit linear regression line above (dB)
LFX - Low frequency extension (Hz) based on -6dB frequency point transformed to log10
LFQ - Absolute average deviation (dB) in bass response from LFX to 300Hz

suffixes:
ON - On-axis response
SP - Sound Power
PIR - predicted in-room response

[kimmosto]

^Yes, patent application is quite thick and difficult. I will add acronym table to avoid searching.

[kimmosto]

This text copied from ASR might provide some extra info:

Differences to patent application by Olive are listed in user manual. Both equations (9 and 10) visible in the patent are available for users.
* Equation 9 (which ASR uses) does not include requirement for on-axis tilt. Tilt can be almost anything so bad sound balance can produce high score if NBDs, LFX and SM_PIR are good. Negative tilt (of LW) produces higher LFX which could increase the problem with automatic iteration. Equation 9 is available for comparison to e.g. ASR, but cannot be recommended for design purposes.
* r^2 is sensitive to absolute value of slope. Certain (usually higher) slopes give higher correlation than slopes close to zero or infinite. r^2 as SM is replaced with scaled 'mean squared error to linear regression' in VituixCAD because equation 10 includes also SM_ON (and SM_SP). Equation 10 includes also AAD_ON so requirement for on-axis tilt is secured, but I prefer logical and stable variables anyway.
* NBD is calculated with "moving" smoothing of 1/2 oct with 6th order Butterworth BP slope because it's available and continuously symmetrical i.e. does not create any steps or variable weights within each band. I have not investigated how much difference this causes compared to calculation with fixed 1/2 oct bands.
* LFX and LFQ 'with sub' are set equal to But18 HP at 17.5 Hz limiting score to 10.0 with equation 9 (max with equation 10 is higher).
* Smoothing for NBD (and AAD) is 1/33 oct because VituixCAD already has internal 1/48 oct. scale. Measurements at home with time window are usually smoothed at mid-range so preference ratings are probably higher while XO simulation than for final speaker measured in large anechoic or with NFS.
* LFX calculation is able to select LW instead of SP for directive LF radiators such as dipoles and cardioids. SP alone is not universal enough for detecting -6 dB point relative to LW at mid...high.

[kimmosto]

Transferred from ASR:

As for use LW instead of SP for LFX of unique speakers; that seems good but will also have to be investigated with real in-room measurements. Take the Magnepan LRS for instance: ...

LW for sure has more bass than SP & ER & PIR, but which one is more accurate for showing bass at the listening position? Since bass is not omni, that means less energy in the room (but the Spinorama does not take into account boundary gain, which the LRS will have a lot of as the driver goes down to the floor).

For example Gradient Revolution having dipole bass has been available since 1993. It's good design measured few times in large anechoic of Aalto University in Helsinki, and numerous times in listening rooms all around. At my home too. Anechoic response does not have any lift at LF. On the contrary, it has shallow tilt down at LF - just like floor standing boxed with low woofer position must have in order to reduce need of EQ. So omni and dipole woofers play with the same rules with floor.
Close to same story with cardioid bass which is more immune to source position. It prefers flatter response (=more pressure) at LF because immediate boost by front wall and front corners is not available (typically for mid-bass).

So LW (or ON) instead of SP is correct method to calculate LFX (and LFQ) for directive LF radiators, and extra penalty of ca. 5 dB due to using of SP would be insane. Weighting of LFX and LFQ in calculation of preference rating could be a bit different story assuming that listening tests might be done mostly with conventional boxed speakers. Olive knows, but more universal equation with better correlation won't probably happen.

[kimmosto]

Rev. 2.0.75.1 (2021-07-22)

Main
* SM of predicted preference rating is calculated as r^2 with slope normalized to -1.0. This scales SM properly without using different function compared to Olive's patent application.

[JonMarsh]

The cumulative development you’ve put into VituiuxCAD, especially the last year, is just amazing to me!

Two thumbs, up, way up!

:T :T

[kimmosto]

Today I've tried to test and adjust NBD calculation. Simple average within 1/2 oct proposed in patent application seem to hide variations compared to smoothing with 6th order BP so my composition is still running in the latest build, and assumed official formulas are hidden. Smooth drivers give low NBD values (0.15-0.20) and PA compression drivers with resonances 2x higher.

[kimmosto]

Rev. 2.0.75.2 (2021-07-23)

Main
* NBD of predicted preference rating calculated according patent application for compatibility reasons despite of sensitivity to slope.

That does not make the first equation (9) more suitable and valid for optimizing. Results are just more compatible e.g. with speaker scores visible on ASR.

[kimmosto]

That does not make the first equation (9) more suitable and valid for optimizing. Results are just more compatible e.g. with speaker scores visible on ASR.

One example how equation 9 can make a mistake. Possibilities that optimizer creates very bad speaker exist.



I'm not sure is patent for method, and equations are just examples which may or may not have some purpose in real life. First wave in my shock was that some benchmark based on amplitude responses only exists, and few individuals have put quite much effort to calculate and publish results on ASR forum. Problem is that view to sound quality is very narrow and superficial. Just overall balance, coloration and some flexibility related to room acoustics is covered. No compression spectrum, timing, non-linearities, intermodulations, total directivity and support for other than conventional/main stream speakers. I wasn't able to tell politely enough that measurements and analyses they use are not comprehensive enough so finally I was banned ops: Second shock wave was that equation 9 (the one ASR members use) runs speaker to bunker with optimizer due to limited/wrong variables. Looks that equation wasn't meant to be taken seriously or common sense was lost for a while - no matter what statistics application told while minimizing variables.

So here we are. VituixCAD has new feature which is questionable. Use it if you dare

[Mogens20]

First wave in my shock was that some benchmark based on amplitude responses only exists, and few individuals have put quite much effort to calculate and publish results on ASR forum. Problem is that view to sound quality is very narrow and superficial. Just overall balance, coloration and some flexibility related to room acoustics is covered. No compression spectrum, timing, non-linearities, intermodulations, total directivity and support for other than conventional/main stream speakers. I wasn't able to tell politely enough that measurements and analyses they use are not comprehensive enough so finally I was banned ops:

Hi Kimmo, I laughed when I read your post about being banned at ASR and 100% agree with your thoughts. Amir likes to believe he is the most knowledgeable person in the audio community. Anyone who challenges his beliefs is not welcome at ASR. If he secretly believes the information or suggestion you communicated is useful, he may change his belief or implement the suggestion but with no discussion or acknowledgement of where this came from. Maybe because he wants his readers to believe it came from his "most knowledgeable" mind? I am not a fan of Amir. Being banned from ASR is nothing to lose sleep over ( not that I was suggesting you were )

Hope you keep up the great work on VituixCAD! :T

[Reet]

One example how equation 9 can make a mistake. Possibilities that optimizer creates very bad speaker exist.



I'm not sure is patent for method, and equations are just examples which may or may not have some purpose in real life. First wave in my shock was that some benchmark based on amplitude responses only exists, and few individuals have put quite much effort to calculate and publish results on ASR forum. Problem is that view to sound quality is very narrow and superficial. Just overall balance, coloration and some flexibility related to room acoustics is covered. No compression spectrum, timing, non-linearities, intermodulations, total directivity and support for other than conventional/main stream speakers. I wasn't able to tell politely enough that measurements and analyses they use are not comprehensive enough so finally I was banned ops: Second shock wave was that equation 9 (the one ASR members use) runs speaker to bunker with optimizer due to limited/wrong variables. Looks that equation wasn't meant to be taken seriously or common sense was lost for a while - no matter what statistics application told while minimizing variables.

So here we are. VituixCAD has new feature which is questionable. Use it if you dare

My thought would be to have the "questionable" equation as option 2, with the "preferrable" equation as option 1 and default selection for new projects.

[kimmosto]

^Yes, that would help to select preferred option for both optimizer and manual adjustments. Another improvement would be to add (optional) SL_ON and SL_LW with adequate weight to equation 9. Strictest action would be to force equation 10 while optimizing. Possible weakness is that equation 10 is not necessarily better than equation 9 boosted with SL.

[kimmosto]

Rev. 2.0.75.3 (2021-07-24)

Main, Preference rating
* Added -2.0*SL_ON checkbox. Target slope is 0.0.
* Added -2.0*SL_LW checkbox. Target slope is -0.3.

Main, Optimizer
* Added warning if both -2.0*SL_ON and -2.0*SL_LW are unchecked when Preference rating is maximized with equation 9.

This solves stability problem of equation 9.

[kimmosto]

Being banned from ASR is nothing to lose sleep over ( not that I was suggesting you were )

My wish was to quit ASR so that username is deleted, but that did not happen. Maybe XenForo has some technical issue related to existing posts, or ban is preferred to prevent interference in the future with new sign in. Anyway, I blamed Amir for almost "everything" including limited view to reality, dictation, filtering of audible/perceivable features proven by science and scores in master preview index, though he has just provided domain and embedded data calculated by other members.
Every audio forum has members who seem to be afraid of subjective observations and personal opinions - own and others', but ASR forum seem to have way too many to be tolerable, imo. Maybe they have profiled themselves as consumers who are being fooled by manufacturers and sellers, and few measured amplitude responses close to specs by Toole et al. is their protection shield. From my point of view (as DIYer, customer and designer of commercial) challenging of lazy/commercial science, experiments, theories and coincidences take technology and performance forward. Nothing happens if no one makes observations and have personal opinions.
So the problem is not just Amir.