Is Jay talking about Amir?

[Hemi-Demon]

Usually IMD can be predicted by just looking the speaker and counting number of ways, but some surprises exist so it's not smart move to skip. For example tweeters could leak pressure from woofer or mid to rear side of the surface causing significantly increased IMD. Conventional coaxial drivers are very bad in 2-way, but also coaxial compression driver in a horn could show quite high IMD also in 3-way.
Real objectivist does not guess and make assumptions (which is mother of all f*****s)



I don't do any official science so I can offer just subjective impressions from few decades. I agree that good timing is not always very perceivable and necessary though it's fundamental feature of sound: energy smoothing causes kinda dynamic distortion in addition to possible changes in timbre. Very dynamic speakers are strong enough with transients such as percussion, acoustic guitar and piano also without perfect timing, but situation gets worse if both fail. For example very simple and cheap Kef 2-way coaxial could produce significantly more dynamic piano hammer than 3-way studio monitor with steep IIR XO. Probability is the same with most of my own designs; close to 1.0 with 2-way and close to 0.0 with 4-way with steep IIR XO. Weaknesses locate to upper bass...low mid e.g. left hand keys of piano.
Personally I don't care very much about changes in timbre. Good spinorama is more important benchmark for that. Investigating audibility of changes in timbre might be more common in science than perceptibility of transient dynamics with whole body. Therefore I have some doubts that official science would help much in this. At least I've been on my own.

University study where one person and probably some gear from Genelec participated indicated that group delay of almost every multi-way with (steep enough) IIR XO is audible. Purist would read that more strictly that I, but it's good time to admit that it's audible. So it should be measured and published on ASR without unnecessary explanations. Significance is case dependent so I'm willing to ignore whole term especially if data is free and easily available.

Are you a speaker designer, and if so would you care to link to some of your creations? Also what is this forum that you keep referencing that details some of the data and grouped opinion you reference in your latest comments?

 

[Blaspheme]

He has said nothing specific or useful in half a dozen posts. Just complaints about this and that. The bar to add measurements is very tall. What absolutely doesn't work is stomping one's feet, threatening to quit, etc. Person needs to demonstrate proper research and strong reasoning. I asked him to provide a single in-room measurements on why EQ is not needed and he refused to provide. So no wonder that nothing else has been forthcoming on the other complaint list either.

Not my argument. I find his thought processes and observations interesting, but what you choose to publish wrt review format is something else. I was wondering why you at times appear to escalate conflict. See "take us hostage". Not a big deal, just a suggestion to do it less, if you can.

 

[More Dynamics Please]

Tough love appears to be the operating philosophy of ASR. As always some will agree with a forum's operating philosophy and some won't.

A kimmosto from Finland is a longtime member of the diyAudio forum and is the author VituixCAD loudspeaker simulation software which would seem to indicate a fair degree of audio technical knowledge.

 

[spacevector]

I feel that there's not many forums left for me anymore. Many...most of the big and significant speaker manufacturers are my clients. In addition, I can't say anything negative about the rest either no matter is it proven by science or just my subjective opinion based on listening impressions because I'm also designer of commercial speakers.
With that background I'm quite allergic to ASR forum where some part of the science is picked, scored and resistance to widen the view and investigations to less significant features exists though they are audible or perceivable for sure proven by science. Measured and published slice of the features could be the most significant, but it should be self evident that "the most significant" does not equal to "all significant" in audio scene. Limiting science to very basic studies and features such as amplitude response alone is not respectable imo. First step is to open mental lock that spinorama rules sound quality exclusively and preference rating is somehow legitimate (with correlation of 0.70 between the predicted and measured preference ratings / US patent...). No one knows all possible significant and measurable features so I'm not requiring "everything possible". Just couple of steps wider view to reality and requirements which should lead to wider range of investigations/measurements. Correlations can be searched later if someone has resources.

I know nothing about March Audio/Zaphodbeeblebrox cases, and not afraid about my designs and tools either. Should be quite widely known that my simulator might be the first one supporting optimising of speaker with spinorama and quasi 3D measurements, and design methods based on measurements and simulations.

Hey, are you the author of VituixCAD?

 

[Blaspheme]

Tough love appears to be the operating philosophy of ASR. As always some will agree with a forum's operating philosophy and some won't.

A kimmosto from Finland is a longtime member of the diyAudio forum and is the author VituixCAD loudspeaker simulation software which would seem to indicate a fair degree of audio technical knowledge.

Not so much tough love, more an unnecessary degree of flouncing.

Thanks for the background info, quite interesting.

 

[gsp1971]

You think 10% is (small) enough to curtail discussion? Crikey.

As Sean Olive said, "listening is still necessary but measurements get you 90% of the way there."
If measurements show a speaker is not good, little you can do (example below).
If measurements show a speaker is well engineered, let the discussions continue on how to best optimize it, equalize it, position it in the room
to achieve the best result.

Below are the measurements of my B&W MT-25 home cinema system. Between 4kHz and 7KhZ there is approximately a 15dB spread!
Please tell me, what actions can rectify the tweeter's performance?
Equalization? Speaker placement? Absorbers?

My point being, if measurements show a really messy speaker, cross it of your list and move on to something better.

Red line: On-axis
Brown line: 15o off-axis horizontal
Yellow line: 30o off-axis horizontal
Green / Blue lines: 7o off-axis down / up vertically

 

[gsp1971]

Tough love appears to be the operating philosophy of ASR. As always some will agree with a forum's operating philosophy and some won't.

A kimmosto from Finland is a longtime member of the diyAudio forum and is the author VituixCAD loudspeaker simulation software which would seem to indicate a fair degree of audio technical knowledge.

Couldn't he be just a really good software programmer, not necessarily a speaker design expert?

 

[Savi]

Couldn't he be just a really good software programmer, not necessarily a speaker design expert?

Unless I am mistaken, he is the one who design taipuu speaker (https://taipuuspeakers.fi/en/taipuu-speakers-dsp-active-speakers/).
I am not a expert and I am not able to judge the quality of its work but from my perspective its work (VituixCAD & taipuu) indicate that he has more knowlegde and experience in speaker design than 90% of the members here.

 

[gsp1971]

Unless I am mistaken, he is the one who design taipuu speaker (https://taipuuspeakers.fi/en/taipuu-speakers-dsp-active-speakers/).
I am not a expert and I am not able to judge the quality of its work but from my perspective its work (VituixCAD & taipuu) indicate that he has more knowlegde and experience in speaker design than 90% of the members here.

Well, in that case, he should have so much to contribute in a positive way.

I don't do any official science so I can offer just subjective impressions from few decades.
His words, post #164

 

[Blaspheme]

As Sean Olive said, "listening is still necessary but measurements get you 90% of the way there."
If measurements show a speaker is not good, little you can do (example below).
If measurements show a speaker is well engineered, let the discussions continue on how to best optimize it, equalize it, position it in the room
to achieve the best result.

Below are the measurements of my B&W MT-25 home cinema system. Between 4kHz and 7KhZ there is approximately a 15dB spread!
Please tell me, what actions can rectify the tweeter's performance?
Equalization? Speaker placement? Absorbers?

My point being, if measurements show a really messy speaker, cross it of your list and move on to something better.

View attachment 141454

Red line: On-axis
Brown line: 15o off-axis horizontal
Yellow line: 30o off-axis horizontal
Green / Blue lines: 7o off-axis down / up vertically

That's the 90%. But if 10% is undecided, then people will likely still argue until the end of time.

But I'd be rude to stop there, even though you didn't catch my meaning. Re your questions I'd say your system's design priority is to fit unobtrusively into a living room and not look overly technical (I've never bought such a system, but I wouldn't buy anything that looked cheap and technical either). If I'm interpreting the graph correctly, your 5 kHz treble gully is deepest at 7º down, so place the speakers lower than your ears. Response at 7º up looks ok there. Similar but not as deep at 30º off axis. It's a surround system, so your energy in the room is not so bad, even though not ideal. Most living rooms will absorb some treble, but these look like they may still be too bright, so reduce the overheated treble ≥ 6 kHz with tone control or (better) DSP. The latter would also address the lack of energy in the lower midrange without too much trouble as it's not deep. The more serious limitation of the system is likely limited dynamics, which you can't fix. How much that matters will depend on audio preferences. I'm assuming the sub isn't part of that graph, the bass peak around 150 Hz is too far up the frequency range to be satisfying.

 

[redshift]

Couldn't he be just a really good software programmer, not necessarily a speaker design expert?

I seriously doubt that he could write competent domain specific software if he didn’t know a thing or two about the subject matter. It just doesn’t happen that way.

The mind projection fallacy.

 

[gsp1971]

I'd say your system's design priority is to fit unobtrusively into a living room and not look overly technical

True, all home cinema satellites are designed for looks as well.

I'm assuming the sub isn't part of that graph, the bass peak around 150 Hz is too far up the frequency range to be satisfying.

Correct. The graph shows the performance of the M-1 satellite without the sub, which I have set to cross at 90Hz.

It's a surround system, so your energy in the room is not so bad, even though not ideal.

With age, I have grown out of home cinema, so I don't use it as a 5.1 system but as a 2.1 system.
When I had all 5 speakers playing music (using the 5ch stereo option in my receiver), the sheer loudness of the system masked any imperfections.
When I switched to 2 speakers, I have experimented with all sorts of placement, sitting lower / higher, pointing the speakers off-axis 10, 20, and 30 degrees, etc, but I never got them to sound right. Vocals sound subdued and veiled, in some recordings there is clear sibilance, while at others, wind instruments pierce your eardrums - not good for a jazz lover like me.
It is clearly a flawed speaker, designed as a lifestyle product targeted primarily to the movie rather than the music audience.

That's the 90%. Most living rooms will absorb some treble, but these look like they may still be too bright, so reduce the overheated treble ≥ 6 kHz with tone control or (better) DSP.

I don't know how to perform equalization or DSP. My audio system is in the living room and not near a computer. I guess I would probably have to buy something like a RME ADI-2 DAC which has that functionality built-in, but I would be paying for a DAC which I don't need.

Besides, the RME ADI-2 DAC costs about €900, and with that money I can simply buy a better pair of speakers.

 

[gsp1971]

I seriously doubt that he could write competent domain specific software if he didn’t know a thing or two about the subject matter. It just doesn’t happen that way.

The mind projection fallacy.

I feel that there's not many forums left for me anymore. Many...most of the big and significant speaker manufacturers are my clients. In addition, I can't say anything negative about the rest either no matter is it proven by science or just my subjective opinion based on listening impressions because I'm also designer of commercial speakers.
His words, post #184.
I stand corrected.

 

[Blaspheme]

True, all home cinema satellites are designed for looks as well.


Correct. The graph shows the performance of the M-1 satellite without the sub, which I have set to cross at 90Hz.


With age, I have grown out of home cinema, so I don't use it as a 5.1 system but as a 2.1 system.
When I had all 5 speakers playing music (using the 5ch stereo option in my receiver), the sheer loudness of the system masked any imperfections.
When I switched to 2 speakers, I have experimented with all sorts of placement, sitting lower / higher, pointing the speakers off-axis 10, 20, and 30 degrees, etc, but I never got them to sound right. Vocals sound subdued and veiled, in some recordings there is clear sibilance, while at others, wind instruments pierce your eardrums - not good for a jazz lover like me.
It is clearly a flawed speaker, designed as a lifestyle product targeted primarily to the movie rather than the music audience.


I don't know how to perform equalization or DSP. My audio system is in the living room and not near a computer. I guess I would probably have to buy something like a RME ADI-2 DAC which has that functionality built-in, but I would be paying for a DAC which I don't need.

Besides, the RME ADI-2 DAC costs about €900, and with that money I can simply buy a better pair of speakers.

Yes, if you are listening to them as 2.1 then their shortcomings will be more apparent. The overheated treble that you see on the FR graph is a likely contributor to sibilance and comparatively veiled midrange. We didn't consider distortion. You didn't mention your usual music source. EQ is handy if available via your source hardware/software (I do it from the computer, which doesn't help your case). DSP performs small miracles, but doesn't fix everything. The RME DAC is very capable but if you buy that you'll really be wanting better speakers (also less able to afford them)

 

[q3cpma]

You shouldn't. Multitone with speakers has nowhere near the value that it has with electronics. The problem here is that the frequency response of each speaker varies. This means the amplitude of each tone varies once it comes out of the speaker. This means that intermodulation between the tones varies and is completely frequency response dependent.

S&R posts the FR for comparison and measure the difference; basically measuring in %. It could be done post equalization, too, but that adds work.

Worse yet, the noise floor is high so the bottom of the graph where we see the nice "grass" in electronics is polluted big time as well.

So the peaks are bad, the floor is bad, and the intermodulation inaccurate due to the first factor. This means as a human you have no chance of looking at the results of multitone and make a quick judgement like you can with electronics that have flat frequency response and vanishingly low noise floor.

I'd say that you need a quite high level to beat the noise floor, indeed.

You have seen me post these measurements. I stopped because I could see no value in them and I know what they are doing! I played a ton with them to try to get them to make sense and they simply don't. Seeing how they add a bunch more work and take away time from reviewing something else, there is no sense in providing such data.

I don't know, you posted it for three 2-way models and noted a significant increase in midrange each time.

Where I agree with you is that if you were to do it again, it'd need some work to be standardized (cf S&R). A bit like the CSD spectrogram, where S&R's is very useful because it uses the same scales every time.

PS: EIA-426B is what S&R uses

 

[gsp1971]

You didn't mention your usual music source.

Source is Oppo BDP-105. Material is CD, SACD, and flac files through a USB drive.

DSP performs small miracles, but doesn't fix everything. The RME DAC is very capable but if you buy that you'll really be I wanting better speakers (also less able to afford them)

My plan is to buy better speakers. Shortlist is Focal Aria 906, KEF LS50 Meta, Revel M16, and Polk R200.
I will also be buying an NCore-based power amp, driven directly by the Oppo or (if funds permit) via a simple active pre-amp.

I understand that equalization can optimize speaker performance. But I will deal with that later once I have my system in place.

Thx for all the input.

 

[kimmosto]

Nothing is being ignored. Everything is considered... But at the end, have settled on the set you see because the rest don't make sense, don't correlate with what sounds good, aren't backed by science, etc.

For a while I thought this is not North Korea where dictator decides what data people need to see and what is important or just interesting for them. But of course you have every right to keep others deaf, idiots or minors under your guardianship. I can't tolerate such arrogance so hopefully someone with moderator rights is able to erase me if you can't.

Also demonstrate that you understand the underlying math that IMD is 100% correlated with distortion of two independent tones. Sum those with phase and you get IMD.

You are talking about single wide band systems such as amplifiers. That kind of simplified assumption is not whole truth with multiway loudspeakers having both mechanical and acoustical links between different ways/bands. Already mentioned few mechanisms such as cone of conventional hifi coaxial (Kef, Seas etc) which acts like wave guide vibrator causing IMD products at HF. That is completely different than result of non-linearities of individual radiators, and can be higher and more audible than harmonics - especially in 2-way applications. PA coaxials usually have some kind of wave guide for tweeter which isolates wavefront of tweeter from vibrating cone so sound clarity could be significantöy better than with hifi coaxial. Another already mentioned mechanism is pressure leak to rear side of the radiator. Leak biases operating point of the motor causing intermodulation products. This happens if designer assumes that tweeter is sealed while it's actually not (enough). This is not all.
Measurement as harmonics is also limited to bandwidth of output port/stage so you cannot measure non-linearities as harmonics in acoustical domain above ca. cone break-up freq. / 2 without multi-tone.

Ok. Your turn to demonstrate that you know at least something about this topic. No problem to accept that you can't make too much noise in the house with multi-tone measurements. Just be honest.

 

[Colonel7]

Someone may not suffer fools gladly because they are very smart or talented, but it is a terrible mistake to assume all others must be fools, especially in their area of expertise. It is a common failing in academia (I feel like I'm trapped at the mid-year toxic dept meeting). Everyone can learn more when things stay civil.

 

[redshift]

For a while I thought this is not North Korea where dictator decides what data people need to see and what is important or just interesting for them. But of course you every have right to keep others deaf, idiots or minors under your guardianship. I can't tolerate such arrogance so hopefully someone with moderator right is able to erase me if you can't.



You are talking about single wide band systems such as amplifiers. That kind of simplified assumption is not whole truth with multiway loudspeakers having both mechanical and acoustical links between different ways/bands. Already mentioned few mechanisms such as cone of conventional hifi coaxial (Kef, Seas etc) which acts like wave guide vibrator causing IMD products at HF. That is completely different than result of non-linearities of individual radiators, and can be higher and more audible than harmonics - especially in 2-way applications. PA coaxials usually have some kind of wave guide for tweeter which isolates wavefront of tweeter from vibrating cone so sound clarity could be significantöy better than with hifi coaxial. Another already mentioned mechanism is pressure leak to rear side of the radiator. Leak biases operating point of the motor causing intermodulation products. This happens if designer assumes that tweeter is sealed while it's actually not (enough). This is not all.
Measurement as harmonics is also limited to bandwidth of output port/stage so you cannot measure non-linearities as harmonics in acoustical domain above ca. cone break-up freq. / 2 without multi-tone.

Ok. Your turn to demonstrate that you know at least something about this topic. No problem to accept that you can't make too much noise in the house with multi-tone measurements. Just be honest.

Ok, let’s give the audience some context to how things work in the eastern region of Scandinavia. Remember to not mention the Swedes and ice hockey.

(Runs for cover)

 

[gsp1971]

Let’s see if we can define the framework.

Multiple choice:
a. I came to this forum to complain about the quality of the measurements (i.e. I believe they are not accurate)
b. I came to this forum to complain about the quantity of the measurements (i.e. I believe they are not enough)
c. I came to this forum to complain about the rules of the forum
d. I came to this forum to complain because no other forum will accept me
e. I came to this forum to show off my technical background by belittling others (by the way many people in here could do this in their area of expertise, but choose not to)
f. I am from Finland, a superior country with superior engineers
g. I came to this forum to contribute to the scientific discussions about speaker measurements and help others make better choices.
h. None of the above.

Please select one. Thx.