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Build of GR-Research LGK 2.0 Speaker

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Rick Sykora

Rick Sykora

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I feel bad for anyone that buys this without the knowledge and tools to fix the short comings of this kit. And, iconically, if you have the needed tools and knowledge then you probably don’t need an all in one kit. This is the type of first time project that can turn people off of DIY.

At around $300 the lack of any instructions and round overs as well as the overall fit and finish is ridiculous.

He is showing the $450 finished cabinet picture for the kit listing instead of the flatpack picture that he should be showing, that has to be a huge letdown for buyers.
It would only take a few minutes to rough out some semi-decent build instructions; I guess he was too busy posing for the giant pictures of himself that are all over the site.
compare the pre-roundover picture above with what is shown for the kit on his site.
View attachment 203271

Yes, while documentation is not GR’s forte, given all the other nagging issues, seems this one was rushed out the door. Still they are very responsive via phone or email.

Will post my measurements and brief listening summary and pack it up for Amir to do a full review. :)
 
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Rick Sykora

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Let's start with a basic impedance measurement...

1651252076292.png


If you compared to the one posted on the GR site, the impedance is very closely matched (certainly within tolerances).

A slight blip around 360 Hz may be a small resonance, but will see what the frequency response reveals...
 

ta240

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.....Still they are very responsive via phone or email.....

That is a nice thing, especially in modern times. Although, having had experience in a past life with diy type products and customers I can say that an hour or so spent putting together some form of instructions would likely save them countless hours of customer support. Being proactive can pay off in more ways too; back then, my greatest fear, that kept me awake at night, was always the unhappy customers that didn't complain and instead just went elsewhere next time.
 
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Rick Sykora

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Now let’s look at frequency response. So, for the first round, here is a gated (and 1/3 octave smoothed for comparison to GR's posted one)...
1651259622071.png


Without knowing and matching all conditions for GR's measurements, it looks pretty close. At 360 Hz, my gated measurements are low res. So for resonances, need to look elsewhere. Other conditions for my measurements were (1m, 80 dB, 4 ms gate). Notably this means I did not measure at the usual 2.83v/1m, so cannot use above for sensitivity.

Another place to look is near-field response for the driver and port...

1651331829453.png

So purple trace is port and aqua is driver (unsmoothed). Given this is a ported full-range driver, I expected worse. The response around 400 Hz does not indicate major resonances. The port output between 1-3 kHz is not pretty and explains why GR discarded the front port in favor of a rear one.

As Amir will review fully, only did some spot listening while on the test stand. Bass extension was pretty good, but power handling is limited. I easily bottomed out the woofer with some Peter Gabriel tunes. As for tonal balance, the midrange seems off to me (notably in comparison to other speakers I own). Will readily admit I may biased by the measurements though!

For the record, all issues I discovered during this build were shared with GR-Research. Until they resolve all of them (not clear as yet), would not recommend this kit for a beginner. Even once all the issues I noted are addressed, there are better values to be had IME.
 
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TheBatsEar

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If you still have them, would you mind bypassing the filter network and fix what you can using a MiniDSP?

That would add context to my suspicion that a MiniDSP might be able to improve the situation some over the passive filter:

Thanks for taking the time out of your day to build this one, you are scholar and a hero to the forum :cool:
 
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Rick Sykora

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If you still have them, would you mind bypassing the filter network and fix what you can using a MiniDSP?

That would add context to my suspicion that a MiniDSP might be able to improve the situation some over the passive filter:

Thanks for taking the time out of your day to build this one, you are scholar and a hero to the forum

Thanks for the kind words!

As for applying a minidsp, would be a bit too much work on this unit. Have some plans for the second set of parts, so might be able to do at some point later. IMO, active filtering will not fix the power handling and is not likely to change the directivity much, so potential improvements are limited by the design.
 

Smitty2k1

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Now let’s look at frequency response. So, for the first round, here is a gated (and 1/3 octave smoothed for comparison to GR's posted one)...
View attachment 203412

Without knowing and matching all conditions for GR's measurements, it looks pretty close. At 360 Hz, my gated measurements are low res. So for resonances, need to look elsewhere. Other conditions for my measurements were (1m, 80 dB, 4 ms gate). Notably this means I did not measure at the usual 2.83v/1m, so cannot use above for sensitivity.

Another place to look is near-field response for the driver and port...

View attachment 203564
So purple trace is port and aqua is driver (unsmoothed). Given this is a ported full-range driver, I expected worse. The response around 400 Hz does not indicate major resonances. The port output between 1-3 kHz is not pretty and explains why GR discarded the front port in favor of a rear one.

As Amir will review fully, only did some spot listening while on the test stand. Bass extension was pretty good, but power handling is limited. I easily bottomed out the woofer with some Peter Gabriel tunes. As for tonal balance, the midrange seems off to me (notably in comparison to other speakers I own). Will readily admit I may biased by the measurements though!

For the record, all issues I discovered during this build were shared with GR-Research. Until they resolve all of them (not clear as yet), would not recommend this kit for a beginner. Even once all the issues I noted are addressed, there are better values to be had IME.
Thank you! Would be interested in what other smallish desktop passive or powered speakers you would recommend.
 

BDWoody

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Thanks for taking the time out of your day to build this one, you are scholar and a hero to the forum :cool:

+1

Really appreciate the work.
 

ta240

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...there are better values to be had IME.

That does seem like a lot of money for what it is. There are a vast variety of speaker kits at and below that price range and for the ones without flat packs, if you have a router to finish the front of this then you likely have a saw to cut your own 'kit'.

Danny seems to have moved into the realm of the online world where he has enough of a following that he can get away with charging this kind of price for a product as poorly packaged as this and regardless of performance. Many people will buy it and like it, simply because of who he represents to them. Maybe pair it with an amp camp amp.... oh no he didn't!
I still have a hard time getting my mind around the fact that now people actively search out sales people to hear their pitches online. Where people once went into stereo shops and kept a bit of apprehension at what the salesman told them; they now decide the salesman is their friend and an educator in their journey and don't question anything they say.
 

voodooless

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As for applying a minidsp, would be a bit too much work on this unit. Have some plans for the second set of parts, so might be able to do at some point later.
Just a measurement of the raw driver in the box would go a long way. Others might give some EQ a go.

All in all pretty nicely done and good writeup!
 

abdo123

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Just a measurement of the raw driver in the box would go a long way. Others might give some EQ a go.

All in all pretty nicely done and good writeup!
Since the crossover filters are known and it's one driver. One might easily take Amir's Spin of the whole thing and reverse engineer it to the raw response.
 

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D!sco

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I feel lucky getting my speedsters before the four softballs worth of magnets drove the price through the roof. I should really send them to @amirm….
 
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Rick Sykora

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While good stuff in speaker recommendations, this is a build thread.

Created a thread for Small DIY speaker recommendations. Will be moving the non-LGK posts there so others can more readily find topic-specific content.

Please use the appropriate thread. Thanks!
 

Wolf

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Sorry, Rick, just answered a question someone had. My apologies...
 

ROOSKIE

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Sorry if I cluttered this, I will say personally just my 2 cents but I think it makes sense to have some info here about other designs so if someone is here now they can easily get started.
Of course there needs to be line somewhere or it will get crazy and thrashed so I do understand that.
Anyway thanks for doing the hard work on the build and post.
Excited to see the Klipple test.
 

Verdinut

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High QTS is usually for huge sealed, free air or passive open baffle.
In this case the qts is higher at .628 but not high. (Over .9 )
It seems suited as a vented box overall but the darn thing is just so small.

Anyway if it was in a sealed box optimized for a .7q it would be 3-4 times vas in size( 3-4l)and likely have zero meaningful bass as it would start rolling off pretty high.

A Qts higher than 0.50 is not suited for a vented box. If you used the BassBox software, you would have found out. Also, for a ported design and for best LF performance, the driver should have a Qts between 0.38 and 0.45.

A good book which explains the functioning of loudspeakers, and describes how to build good cabinets etc, is this book but it is very technical:
"Loudspeaker Design Cookbook 7th Edition" by Vance Dickason. You can get in from Amazon.
 

ROOSKIE

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A Qts higher than 0.50 is not suited for a vented box. If you used the BassBox software, you would have found out. Also, for a ported design and for best LF performance, the driver should have a Qts between 0.38 and 0.45.

A good book which explains the functioning of loudspeakers, and describes how to build good cabinets etc, is this book but it is very technical:
"Loudspeaker Design Cookbook 7th Edition" by Vance Dickason. You can get in from Amazon.
It is port appropriate because the fs is higher.
It is a relationship between the two.
With higher fs drivers(90-120) higher QTS/QES(.5-.9) is good for ported boxes.
Over .9 would change things a bit but that would be a very unique driver.
Model this driver yourself.

With a higher fs driver you are tuning the port to support what is the upperbass/midbass and not the lower bass region. Therefore the desired QTS/QES parameters are different from when tuning for the tradition bass zone.
In a driver where the fs is lower and the natural response already covers the midbass you would get a peak or boom there, not so in a driver like this where the natural response is severely rolled off in the midbass and needs support.
Also the driver has a high fs so even tuning for midbass you are tuning well below fs.
If this driver was in a small sealed box it would have no bass at all and barely any lower midbass. Completely unsuitable response in this use case.
 
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Rick Sykora

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Sorry, Rick, just answered a question someone had. My apologies...
Sorry if I cluttered this, I will say personally just my 2 cents but I think it makes sense to have some info here about other designs so if someone is here now they can easily get started.
Of course there needs to be line somewhere or it will get crazy and thrashed so I do understand that.
Anyway thanks for doing the hard work on the build and post.
Excited to see the Klipple test.

Np, my fault. Once I started, knew others would likely pile on. So am just as guilty.

After seeing this happen more than a few times now, good to give the question its own home.
 
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