GR Research LGK 2.0 Speaker Review (A Joke)

[ROOSKIE]

Yes, this is part of the problem... The driver's Fs is around 120hz, so that is useless because lacking any bass. But the cabinet is a Bass Reflex design using the sub tuning trick in order to boost somewhat the bass. In this case the cabinet is tuned around 80hz (the minimum between impedance peaks), and the result is an insane peak above 100hz ( which also interacts with the passive Eq netwoork...). This insane BR tuning is what causes distortion because cone movement cannot be under control as a sane BR design would allow. But this would also mean sacrifice bass, tuning the BR at 120Hz or above.

2db over a less than 50hrz wide zone is not even remotely an insane bass peak and has little effect on the drivers excursion there.

The issue is that the driver is small and it takes a lot of movement to generate anything under 125hrz and substantial displacement to get something like 70-80hrz kick drums or electronica beats. The port is tuned to 80hrz and as such the unit is subjected to a significant and a constant quantity of content below the tuning frequency. There is a ton of stuff in music at 60-80hrz.
Content below the port tune is bad for most every ported design but often at 30-40-50hrz or even 60hrz tunings there is little content below to cause extreme distortions and usually it happens fast enough one thinks it is just the way it sounds on the recording (until you hear it without all that sub port junk and overexcusion IMD/doplar) and some designs are crafted to roll off faster below fb or smartly use DSP to either alter a myriad of things keeping the driver in check longer (often at the expense of something else though).

This driver should be High Passed at 100-120hrz and used for quite farfield or perhaps pretty lively nearfield. I would still keep the ported enclosure to allow for a better blending with the sub. A sealed version of this speaker would be possible but have absolutely no bass and need to be crossed more like 150-180hrz.

Total waste of speaker based on price.

Now maybe a need to test these just to see...
$159 pair no filter https://www.madisoundspeakerstore.com/full-range-speaker-kits/markaudio-tozzi-one-kit-pair/
$120 pair includes 2 filter options https://www.parts-express.com/Copperhead-Desktop-Full-Range-Speaker-Kit-Pair-300-7180

 

[amirm]

Try adding smoothing to your plot and it will look radically similar. You're comparing apples with oranges...

You didn't bother reading the next sentence in the review???

"I have circled some of the reasons the two graphs look different. Danny is using improper and heavy filtering (1/3 octave) for his measurements. This gets rid of the myriad of variations you see in my graph. He also uses gated response to get rid of room reflections which in the process removes any resolution below a few hundred Hertz. This is why his graph starts at 200 Hz rather than 20 Hz."

Do read before shooting from the hip in the future.

 

[amirm]

So the issue isn't just that there is no standard, but also that the test itself produces unreliable results? That's frustrating. If you were to tackle this, how would you approach it? I've seen Erin's IMD graphs in his driver measurements, often for bass and larger diameter woofers.

Results are reliable but just not comparable. As an R&D tool, it works if you stay with the same design/frequency response and optimize distortion. Doesn't work for reviewing when every speaker is different. A driver is also different since the signal won't be split between it and other speakers.

And no, I don't know yet how to solve it. I spent a lot of time on it in the past but could not get anywhere. I will have to think about a way to get there....

 

[hardisj]

I am not an expert on speaker design but for a driver like this I was under the impression that you are supposed to cross them over before resonance to avoid problems as things become unstable at the resonant frequency. The resonant frequency of this driver is 120 Hz which is right where things get crazy. The published impedance data shows the strong peak at 120 Hz and some phase changes as well and it not that much different than what Amir measured. To me it looks more like the design is broken rather than anything mechanically wrong with the speaker.

I've been measuring drive units and speakers for well over a decade now and have run into every possible oddity one can. I'm telling you, I have never, ever seen a speaker that exhibits the resonance issues this one does at the impedance peaks. The closest I have seen is when a speaker is mounted to a flat panel and that panel is resonating in sync with the drive unit itself.

But, let's say you are correct about 120Hz Fs of the driver wrt the apparent issue in the impedance of the speaker (driver+enclosure). What about the other impedance issues we see below this? They don't past the sanity check for the Fs as the issue. For that matter, go look at the impedance data for every ported speaker so far that has been measured. There are a number of them that use extended shelf designs where the port tuning is below the Fs of the driver. For example, Kef R3, Monolith Encore T6. Those don't show these issues. And that's with 1/20th-octave "smoothing" applied and a 0.73Hz resolution sweep.

So, I stand firmly by my analysis that something is amiss here. And if I had to place money on it, I'd say it's the enclosure/build. I'm leaning toward turbulence in the port but it could well be that the enclosure is not built to snuff. Or, hey, maybe it's those damned little "tube connectors". Things that make you go "hmmm".

(Oh, FWIW, impedance resonances are usually more noticeable when the signal voltage is low and/or there is little/no averaging. Therefore, based on actual experience, I'd wager it's nothing to do with the drive level)

Whether or not it ultimately impacts the overall performance of the speaker remains to be seen. However, it's a red flag, nonetheless and I’d be interested in knowing the cause.

 

[mhardy6647]

At $250-$300 I have a feeling those might be snake oil.

Heaven forefend!
Indeed -- the minor shortcomings (mere anomalies, in the great scheme of things) observed by @amirm in his testing would certainly be mitigated fully and completely with just a few hundred dollars' worth of simple components -- a mere handful (of cash or componentry)! I suspect that even his wife, were she listening out in the kitchen, would be shocked, shocked by the jaw-dropping improvement in performance.

 

[Newman]

it’s the Dayton PS95

It’s not. The surround of the GR is not inverted, the outer ring with the mounting holes looks different.

I also reckon it is the PS95, or one that has a ‘shite mod upgrade’ by GR. Too many physical similarities, plus same Fs 120Hz, plus same claimed Xmax 2.5mm….

[edit] OTOH something like this is also a candidate… https://www.aliexpress.com/item/32921600959.html

…especially if GR put in a bulk order for it with no whizzer cone, or even removed it themselves in another ‘shite mod upgrade’.

 

[Soniclife]

So, I stand firmly by my analysis that something is amiss here. And if I had to place money on it, I'd say it's the enclosure/build. I'm leaning toward turbulence in the port but it could well be that the enclosure is not built to snuff. Or, hey, maybe it's those damned little "tube connectors". Things that make you go "hmmm".

If there is a pair is it worth measuring the other one?

 

[amirm]

I've been measuring drive units and speakers for well over a decade now and have run into every possible oddity one can. I'm telling you, I have never, ever seen a speaker that exhibits the resonance issues this one does at the impedance peaks.

I have seen it a number of times in my setup. What resolution is your impedance measurements? Here is the same measurement but at lower resolution:

All the kinks are gone now.

 

[dbaudio]

This whole riff around the "tube connectors" is nonsense. Just draw a link budget diagram and insert relevant resistance parameters at each point in the bonding diagram.
"Tube connectors" get you nothing and possibly (likely) less than nothing other than having spent way too much snaky cash.

 

[Bruce Morgen]

This whole riff around the "tube connectors" is nonsense.

That's just the tip of a very big iceberg of "nonsense" Mr. Richie constantly promotes on U-Toob.

 

[hardisj]

I have seen it a number of times in my setup. What resolution is your impedance measurements?

I said 1/20th above in the same quote you pulled the above from:

Those don't show these issues. And that's with 1/20th-octave "smoothing" applied

I use 1/20th to purposely match that of the FR I am providing.

Here is the same measurement but at lower resolution:

All the kinks are gone now.

So, what is the usual impedance resolution you provide then? Are you saying this is at a higher resolution than you normally provide? Surely not (I am hoping you will clarify this before others run wild with the open implication).

With that said, where are examples of others behaving this poorly at the impedance peaks where you use the same smoothing as you did in your OP for this speaker? I've yet to see any. I know I don't have any of my own even when using 1/20th smoothing for impedance. Other than a drive unit on a flat baffle or maybe some in-wall speakers where the issue is not the fault of the actual speaker itself but rather the mounting.

Again, the results we see here are not typical and I am curious as to what is causing them. Is this an issue with the kit or the build? Is that answerable by you at this point? Might be worth investigating further. Especially if you choose to make a video for this one.

 

[Newman]

I said 1/20th above in the same quote you pulled the above from

Are you suggesting that Amir should “read before shooting from the hip in the future”? LOL

 

[amirm]

Are you saying this is at a higher resolution than you normally provide?

No. It is the same. I just lowered just now it to show that at lower resolution you can't see them.

 

[hardisj]

No. It is the same. I just lowered just now it to show that at lower resolution you can't see them.

Understood. I figured you had ran it the same as you had for all others. So, the question still stands... wth(eck) is going on with this speaker for it to be showing those attributes?...

 

[amirm]

Hard to imagine anything is wrong with it given the frequency response.

 

[hardisj]

Hard to imagine anything is wrong with it given the frequency response.

I disagree. But I've already given all my reasons why. If you don't feel like exploring it further because you find it unnecessary then that's perfectly fine. You've got enough to do I'm sure. Just wanted to bring it to everyone's attention, though, that something is indeed weird about those results.

I'll leave the matter be from here.

 

[amirm]

I use 1/20th to purposely match that of the FR I am providing.

This insufficient by the way with respect to knowing what the resolution of your graphs are. That octave setting is the display resolution, NOT the underlying measurement resolution. If the latter is low, it doesn't matter how high you set the display resolution.

 

[Rick Sykora]

If there is a pair is it worth measuring the other one?

I have the parts for the second one, but unclear why would get any different results from my test rig than the one Amir has. As mentioned earlier here and in the build thread, my impedance measurement did not exhibit any of the jaggedness of Amir's original one.

As has been pointed out by Amir and others, there are other significant indicators that the speaker is representative of GR's design. If Amir feels further investigation is warranted, am here to support him and ASR.

For the record, I think it is worth mentioning that behind the scenes, the LGK 2.0 is mainly the work of Danny's assistant.

 

[amirm]

FYI this is another example of glitches in low frequency impedance graph:

 

[amirm]

As has been pointed out by Amir and others, there are other significant indicators that the speaker is representative of GR's design. If Amir feels further investigation is warranted, am here to support him and ASR.

It really is not warranted. The two of us have already incurred significant expense and effort with this project/testing. There is no reason to believe anything better to go through all of this again. Company had the opportunity to send me a sample and refused. If they don't care, then that is it.