GR Research LGK 2.0 Speaker Review (A Joke)

[Mark_A]

IMD measurements are not the answer to that. Certainly no "watts" number jumps out of that measurement, especially if it is a spectrum and not a number.

I never suggested that a watts measurement has anything to do with IM. I merely pointed out that the average consumer is constantly looking for more objective ways to evaluate speaker systems, partly because the industry has moved toward online purchases without listening tests in many cases. In such cases, they often erroneously latch onto published specifications, such as the power rating of a speaker system in watts, which has almost nothing to do with the sound quality or the SPL output of the speaker.

 

[thewas]

Also Klippel seems to offer a multitone distortion measurement which Erin and Nuyes recently use, for example

source: https://www.erinsaudiocorner.com/loudspeakers/wharfedale_linton_85/

source: https://gall.dcinside.com/mgallery/board/view/?id=speakers&no=255172&search_head=110&page=1

In my experience it has a better correlation to audibility than the HD measurements which can be seen for example also in how the MD gets lower at single driver when a high-pass filter is used while a HD measurement would stay the same:

Multitone Distortion​

The following tests are conducted at (4) approximate equivalent output volumes: 70/79/87/96dB @ 1 meter. The (4) voltages listed in the legend result in these SPL values.

The test was conducted in (3) manners:

1. Full bandwidth (20Hz to 20kHz)
2. 100Hz to 20kHz
3. 200Hz to 20kHz

The reason for the additional two measurements is because it is unfair to expect a small speaker to extend low in frequency. Applying these three tests will provide a good idea of the limitations if you were to want to run the speaker full range vs using it with a HPF. However, note: the 2nd and 3rd test low frequency limits are a “brick wall” and don’t quite emulate a standard filter of 12 or 24dB/octave. But… it’s close enough.

For information on how to read the below data, watch this video:

1. Full bandwidth (20Hz to 20kHz)

1. 100Hz to 20kHz

1. 200Hz to 20kHz

Direct Comparison (96dB @ 1m)

Source: https://www.erinsaudiocorner.com/loudspeakers/parts_express_copperhead/

I recently asked @JohnPM from REW if he can implement some similar test and visualisation in REW and he said he is looking into it.

 

[amirm]

In my experience it has a better correlation to audibility than the HD measurements which can be seen for example also in how the MD gets lower at single driver when a high-pass filter is used while a HD measurement would stay the same:

It doesn't though. With a single tone, we can easily perform psychoacoustic modeling of audibility. With dual tone, you are on your own. Modeling that masking effect becomes much harder. Add more tones and you really have no idea what is going on. There is no metric to apply to those graphs either. How do you compare one shape of graphs to another???

 

[thewas]

It doesn't though.

It does, there is a reason why Klippel offers them and Prof. Goertz does and show them, also see the advantage I showed above with a wide band driver when its high passed, we hear rather the MD at -10 or -20 dB than HD at -30 or -40.

For example, the HD plot gives the impression that above 400 Hz the distortions are not very audible which is actually true for a single tone like a sine sweep since they are lower than 3% and actually mainly 2nd order, 3rd oder which is more audible is less than 1%:

As you know from your review with the similar LGK such loudspeaker sounds extremely distorted though at the same level when playing music which has also at the same time a bass part, which can be seen at the multitone distortions which are at approximately 33%! (red curve):

Also as hearing experience tells with such small loudspeaker when they are sufficiently highpassed the audible distortion drops significantly which can be seen also by the more than 10dB drop above.

With a single tone, we can easily perform psychoacoustic modeling of audibility. With dual tone, you are on your own. Modeling that masking effect becomes much harder. Add more tones and you really have no idea what is going on.

There are different issues, also I haven't seen any posted psychoacoustic evaluation at the typical HD plots shown?

Also it is not that I see no use in the HD plots, but they tell different things and I would rather have both complementing the distortion view of a loudspeaker. Neumann has some nice examples at pages 15-16 https://en-de.neumann.com/product_files/7950/download which show the significant multitone distortion difference of loudspeakers when the number of ways/drivers are increased, although the harmonic distortion measurements of all are low.

There is no metric to apply to those graphs either. How do you compare one shape of graphs to another???

Like you compare HD plots, the higher the distortions are the more probable it is to hear them, same goes for the frequency regions where distortion is more audible.

 

[amirm]

There are different issues, also I haven't seen any posted psychoacoustic evaluation at the typical HD plots shown?

??? I do that routinely in my comments about the graph.

 

[amirm]

For example, the HD plot gives the impression that above 400 Hz the distortions are not very audible which is actually true for a single tone like a sine sweep since they are lower than 3% and actually mainly 2nd order, 3rd oder which is more audible is less than 1%:

That graph is no good because it is not showing you the ratio like you are using with IMD. For most cases, relative THD is far more important because it is responsive to frequency response variations.

 

[amirm]

As you know from your review with the similar LGK such loudspeaker sounds extremely distorted though at the same level when playing music which has also at the same time a bass part, which can be seen at the multitone distortions which are at approximately 33%! (red curve):

You don't need an IMD graph to tell you there was plenty of distortion with the LGK:

Notice my comments on the left graph. I am explaining audibility based on perceptual model which you can't do with IMD.

 

[Ilkless]

And the Soundkraft you tested shows that a widebander can do a massive ton better! So this is squarely on Danny, not necessarily the format of design.

 

[thewas]

??? I do that routinely in my comments about the graph.

I mean a psychoacoustic model based metric not your listening impressions.

That graph is no good because it is not showing you the ratio like you are using with IMD. For most cases, relative THD is far more important because it is responsive to frequency response variations.

The MD plots I posted above show also the relativ to fundamental distortions, here again:

 

[amirm]

I mean a psychoacoustic model based metric not your listening impressions.

That is exactly what I answered. And gave example of this very LGK speaker in the next post.

 

[amirm]

The MD plots I posted above show also the relativ to fundamental distortions, here again:

I know. But you compared it to an HD graph that wasn't. You can't make that comparison. You have to use relative distortion in both cases.

 

[amirm]

The MD plots I posted above show also the relativ to fundamental distortions, here again:

And what does that graph tell you? That it produces more distortion at 20 kHz than it does at 50 Hz in real life with music??? It ain't so....

 

[thewas]

I know. But you compared it to an HD graph that wasn't. You can't make that comparison. You have to use relative distortion in both cases.

I also showed relative HD?

You don't need an IMD graph to tell you there was plenty of distortion with the LGK:

Notice my comments on the left graph. I am explaining audibility based on perceptual model which you can't do with IMD.

You explain what you think happens which is wrong though, at normal listening to music with simultaneous bass not the approx. 1% 2nd harmonic distortion is what you hear but the multitone distortion which is magnitudes higher.

And what does that graph tell you? That it produces more distortion at 20 kHz than it does at 50 Hz in real life with music??? It ain't so....

How do you know? As you know from your listening tests of the LGK such loudspeakers have horrible "crackling" at large multitone levels sounds which have also a high upper frequency content.

 

[Mark_A]

You don't need an IMD graph to tell you there was plenty of distortion with the LGK:

Notice my comments on the left graph. I am explaining audibility based on perceptual model which you can't do with IMD.

I don't think it is fair to expect a speaker system that has only one 3" driver to play at 86 dB without distortion.

 

[tvih]

I don't think it is fair to expect a speaker system that has only one 3" driver to play at 86 dB without distortion.

Probably shouldn't market it as a giant killer, then

 

[tomtoo]

I don't think it is fair to expect a speaker system that has only one 3" driver to play at 86 dB without distortion.

See if you think its a good desktop speaker for the price, buy it. But let others decide that its regarding the price, a poor desktop speaker. Or do you have some arguments that are interesting to listen too?

 

[YSC]

I don't think it is fair to expect a speaker system that has only one 3" driver to play at 86 dB without distortion.

then don't say it's a giant Killer which it outdo those over it's size class... it's like calling a Mazda MX5 (miata) as a ferrari killer... it maybe good for it's size class, but not giant killer

 

[mhardy6647]

but, but, but... it's a little giant killer -- I guess that means it kills little giants, oxymoronic though that may be.

 

[amirm]

I don't think it is fair to expect a speaker system that has only one 3" driver to play at 86 dB without distortion.

It is more than fair. That is just 1 or two watts of power. Company itself shows driver response at 84 dBSPL:

And even brags about it on the website: "The LGK 2.0 uses a small 3″ wide-band driver providing a smooth response from to 80Hz to 20KHz and at an impressive 84dB."

If it is impressive at 84 dB, you think it should go to pieces at 86 dBSPL???

Remember, I have tested 250 speakers that passed this test. Company advertises that this speaker competes or "kills" many of them. It clearly does not if it can't handle 86 dBSPL. That they selected a small driver with just 1 mm of excursion is their problem, not mine or the customer who buys this.

 

[Mark_A]

If it is impressive at 84 dB, you think it should go to pieces at 86 dBSPL???

Remember, I have tested 250 speakers that passed this test. Company advertises that this speaker competes or "kills" many of them. It clearly does not if it can't handle 86 dBSPL. That they selected a small driver with just 1 mm of excursion is their problem, not mine or the customer who buys this.

It is certainly possible that a speaker that functions ok at 84 dB could go to pieces at 86 db. It's not a a matter of "should."

I think it is perfectly fine to point out that it went to pieces at 86 dB, but I think it would have been best to test it at a lower dB levels, such as it might be used in a real world application of that speaker. In the real world, such as that system being used as a computer speaker, the listening distance may be only be one half meter or less. My computer speakers cannot play at 86 dB at one meter without distortion.

Personally, I think he should have tried designing a system with 2 or 3 those full range 3" drivers (without a crossover, but apparently with a notch filter. Obviously the impedance of the individual drivers would have to be adjusted to run them in parallel.