New mysterious Genelec monitors

[RobL]

Waveguides can only ever constrain radiation. They can never make it wider. What's done for tweeters to widen radiation in the HF is inserting a phase plug. At the crossover waveguides constrain the lower range of the tweeter so it does not destructively cancel with the higher range of the woofer.

Actually, @ctrl just showed in the Focal Solo 6 review how a flat, recessed waveguide will widen tweeter dispersion up to 9khz.

 

[Curvature]

Actually, @ctrl just showed in the Focal Solo 6 review how a flat, recessed waveguide will widen tweeter dispersion up to 9khz.

That's interesting. The basic technique still has to do with restriction, though, since a waveguide can't create more energy than there was initially.

 

[bogart]

Just think about it. He sits maybe ~3m away from the speakers so what’s the point of having 120+ dB speakers ?

Alignment of the equipment to how it's used is essential engineering practice. Even more - why take a room out of commission to add headroom that just isn't necessary? That's money lost (can't work in there) and money spent (new gear). Unless they're selling the old gear, then it's probably a cascade to another room, which means more downtime to re-configure... all this for no discernable benefit.

For perspective, I was at a (fantastic!!) concert last night hearing Between the Buried and Me. Using an iPhone with a decently usable SPL meter, I was getting 112-115 dB at the soundboard where I stood... and I was seriously glad to have earplugs in. 125 dB at 1m is 115 dB at 3m... these are unbelievable levels for working conditions.

 

[Blockader]

You misunderstand. In the graph what's shown is the response of a pressure microphone, which are used in specific scenarios (like closed box tests). The microphone we use for measurement are free field and do not have that kind of aberration. There's a difference in construction which accounts for the change in response. Pressure microphones are also more directionally sensitive than free field mics.


This is perfect CD, taken from Geddes' paper.

View attachment 295059

Another "more feasible" version of the same.

View attachment 295060

Here's his model on a great loudspeaker's polar pattern:

View attachment 295061

I think you're overstating the case when you talk about the "definition" of CD in terms of DI, same as you do for dipole or cardioid speakers "interacting with the room less" (dipoles excite pressure minima where monopoles excite maxima, while cardioid speakers have limited relevance in the modal region of small rooms). Same goes for this overstatement:

Unless there have been some kind of preference studies done that I'm unaware of, there are no separate target on axis curves for those speakers.

Almost none of this pertains to a "psychoacoustical perspective" about constant vs. rising DI you wrote about originally.

I don't know why you have shared Geddes' ideal constant directivity plots iwth me. Cardioid speakers basically interact with the room less because they excite room modes less, because they have narrower dispersion pattern in bass. They send less energy to side walls or generally to walls in low frequencies. Cardioid/Dipole speakers steady state response with constant CD and flat on-axis response is different than monopole forward firing speakers with constant CD and flat on-axis response because their DI is different. Are you suggesting me that a speaker with a DI of 4.8 from 80hz and 20khz should have flat on-axis just like speakers which have rising DI 0.0 to 6.0 from 200hz to 20khz? I don't know how can you be sure about that without having a research about it because they will have different in room responses. Yes, direct sound is dominant I know. Yet, in room response also matters.

I don't know what we are debating about at this point to be honest. Maybe, if you are willing to, prove me that having reflections that sound different than on-axis sound benefit anything in sound reproduction please.

 

[Blockader]

Waveguides can only ever constrain radiation. They can never make it wider. What's done for tweeters to widen radiation in the HF is inserting a phase plug. At the crossover waveguides constrain the lower range of the tweeter so it does not destructively cancel with the higher range of the woofer.

this is wrong, it is possible to get increased width from waveguides through adding diffractions. Basically waveguides are diffraction control units and diffractions can make the dispersion pattern wider.

 

[Curvature]

this is wrong, it is possible to get increased width from waveguides through adding diffractions. Basically waveguides are diffraction control units and diffractions can make the dispersion pattern wider.

Diffraction only happens with wavelengths larger than the pathlength and obstacle. Although otherwise that's a fair point.

 

[youngho]

this is wrong, it is possible to get increased width from waveguides through adding diffractions. Basically waveguides are diffraction control units and diffractions can make the dispersion pattern wider.

the Seas DXT tweeter

 

[Curvature]

I don't know why you have shared Geddes' ideal constant directivity plots iwth me. Cardioid speakers basically interact with the room less because they excite room modes less, because they have narrower dispersion pattern in bass. They send less energy to side walls or generally to walls in low frequencies. Cardioid/Dipole speakers steady state response with constant CD and flat on-axis response is different than monopole forward firing speakers with constant CD and flat on-axis response because their DI is different. Are you suggesting me that a speaker with a DI of 4.8 from 80hz and 20khz should have flat on-axis just like speakers which have rising DI 0.0 to 6.0 from 200hz to 20khz? I don't know how can you be sure about that without having a research about it because they will have different in room responses. Yes, direct sound is dominant I know. Yet, in room response also matters.

I don't know what we are debating about at this point to be honest. Maybe, if you are willing to, prove me that having reflections that sound different than on-axis sound benefit anything in sound reproduction please.

I quoted Geddes because you use him as a reference, so are likely inclined to take his work seriously, and because you stated: "Constant directivity does not really aim for on-axis flat response. Constant directivity is constant behavior of the frequency dependent off-axis/on-axis ratio.(both rising DI and flat constant DI fit to this definition)". CD is more of goal than a reality.

1. The Perfect CD graph speaks for itself: flat response over a certain coverage region with a sharp drop at a certain angle at all frequencies.
2. The more feasible CD graph shows similar coverage with more gradual attenuation at all frequencies.
3. And then the model speaker graph shows neither consistent attenuation nor frequency behaviour. Although it's certainly very smooth.

There's plenty of examples of speakers that achieve (3), and (3) looks like (2) in places. Many designers believe that flat DI after a certain point is so important that they are willing to have a sudden change in slope to achieve that (even several changes in slope with multiway speakers, like in the large Perlistens). We know that plenty of successful speakers implement this approach. Even Neumann speakers attempt CD in HF through waveguides.

This was after my initial question to you, when you said DI profiles had a psychoacoustic basis. You did not provide anything on this topic other than citing Toole and referencing Geddes. I have no problem with their research, but you are stretching their conclusions. As far as I know the psychoacoustical links they identified have not been fully explored. Certainly not explored enough to model the results of the preference research in terms of human auditory processing. That's my main interest.

My objection to your discussion of CD was that I don't believe that it was the basis for the speakers did well in the preference research. Many of them certainly had regions of CD-like behaviour, but CD was never set as a design goal other than in specific cases. Another misstatement you made was that we know the preferred design targets for non-monopole speakers. You provided no research to back that. I haven't seen preference research in that respect either.

I think you may have a habit of making stronger claims than you mean.

 

[Blockader]

I think you may have a habit of making stronger claims than you mean.

This is what I said before:

just a food for thought, do not take what I said too seriously.

If I go into the part where Toole talks about the precedence effect or fusion interval I can show you more evidence to support my claims. What is the point though? in ASR, we're not big fans of bringing fresh ideas. We don't really bring new ideas to the table and talk about possibilities based on past research. We don't like to take the findings of past research and apply them to areas that haven't been well covered. (right or wrong, exchanging ideas is what matters) We tend to avoid extrapolating research findings to areas that have not been thoroughly explored. What we like to think is that we know everything about dipole speakers, cardioid speakers, omnidirectional speakers, monopole speakers. They should all share same design characteristics regardless of their frequency dependent off-axis behavior. We solved everything. Long live science.

 

[Pearljam5000]

It would be interesting to hear them next to ultra hi end "audiophile" speakers
like KEF Blade , Wilson Chronosonic , Focal Utopia, B&W 801 D4" etc

 

[fpitas]

It would be interesting to hear them next to ultra hi end "audiophile" speakers
like KEF Blade , Wilson Chronosonic , Focal Utopia, B&W D4" etc

With the caveat that all the high-end speakers listed may not have an exemplary response. Some tracks might benefit from the unintentional re-mastering, some not.

 

[Curvature]

This is what I said before:

If I go into the part where Toole talks about the precedence effect or fusion interval I can show you more evidence to support my claims. What is the point though? in ASR, we're not big fans of bringing fresh ideas. We don't really bring new ideas to the table and talk about possibilities based on past research. We don't like to take the findings of past research and apply them to areas that haven't been well covered. (right or wrong, exchanging ideas is what matters) We tend to avoid extrapolating research findings to areas that have not been thoroughly explored. What we like to think is that we know everything about dipole speakers, cardioid speakers, omnidirectional speakers, monopole speakers. They should all share same design characteristics regardless of their frequency dependent off-axis behavior. We solved everything. Long live science.

You weren't "extrapolating"... you were writing about the topic as if the answers are already known, not as if you were presenting ideas.

If you like start a new thread and we can keep going.

 

[juliangst]

With the caveat that all the high-end speakers listed may not have an exemplary response. Some tracks might benefit from the unintentional re-mastering, some not.

Kef Blades are pretty much textbook perfect but they have a steeper slope than typical genelecs

 

[fpitas]

Kef Blades are pretty much textbook perfect but they have a steeper slope than typical genelecs

View attachment 295114

KEFs are nice, yes.

 

[Blockader]

You weren't "extrapolating"... you were writing about the topic as if the answers are already known, not as if you were presenting ideas.

If you like start a new thread and we can keep going.

I said do not take me seriously, I am just presenting a food for thought. What else can I do?

 

[Curvature]

Kef Blades are pretty much textbook perfect but they have a steeper slope than typical genelecs

View attachment 295114

Note that the KEF EIR slope changes at 2-3kHz while the Genelec's remains consistent.

 

[juliangst]

Note that the KEF EIR slope changes at 2-3kHz while the Genelec's remains consistent.

Not sure how representative the Kef measurement is. Yes they have a Spinorama now but the measurements for the Reference 1 Meta for example are a little different from Erin's measurments (dottet line is from Kef):

 

[Curvature]

Not sure how representative the Kef measurement is. Yes they have a Spinorama now but the measurements for the Reference 1 Meta for example are a little different from Erin's measurments (dottet line is from Kef):
View attachment 295119

It's hard to say. I don't think there will be enough divergence between KEF and EAC (or ASR measurements in other speakers) to affect large trends seen in composite curves like EIR unless there was significant or systematic error. The change in slope in the Blade 1 vs 8361 EIR you posted covered several octaves.

 

[Pearljam5000]

So which is better 8361 or KEF Blade ?

 

[Curvature]

I said do not take me seriously, I am just presenting a food for thought. What else can I do?

Anyway, you were giving us evidence based data on the benefits of having differences between on-axis/off-axis sound. What's up with that?

I think some of the issue here is that English isn't the first language for either of us.

I don't have issue with the general idea that on-axis response should be similar to off-axis. Where I see a problem is in CD attempts in real speakers, given what artefacts they cause in off-axis response (e.g., the change in slope at MF/HF). They do sound good, though. Way better than designs which allow directivity errors off-axis.

Unfortunately it's not clear what would be better. In general I don't think we are nearly at the end of directivity research. Monopole (cardioid included), dipole, and omnidirectional speakers often have such different radiation patterns (and there are few examples that have FR as equally controlled as in monopoles) that any meaningful discussion of their benefits is lost to FR error.

If there was a way to listen to a speaker with consistent on-axis but manipulable off-axis response, that would be a start.