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GR Research X-LS Encore Kit Speaker Review

amirm

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#1
This is a review and detailed measurements of the GR Research X-LS Encore DIY Kit speaker. It was kindly put together by member @Rick Sykora. You can see his build thread here: https://www.audiosciencereview.com/forum/index.php?threads/build-of-gr-research-x-ls-encore.14312/

The bare kit without cabinet costs US $249. Unfortunately they do not sell the cabinet parts so you have to source that elsewhere or build it yourself as Rick did. As supplied, this is one heavy, dense bookshelf speaker due to use of thick MDF for cabinet construction:

X-LS Encore Kit DIY Speaker Review.jpg


The back panel shows the somewhat utilitarian binding posts and the port:

X-LS Encore Kit DIY Speaker Bookshelf 2-way Back Panel  Review.jpg


This is also quite a deep speaker so don't think about using it on the desktop. I evaluated it as a hi-fi speaker in far field.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

I used over 800 measurement point which was sufficient to compute the sound field of the speaker. Measurement axis is the tweeter center.

Temperature was 78 degrees. Measurement location is at sea level so you compute the pressure.

Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications.

Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

X-LS Encore Kit DIY Speaker 2-way bookshelf spinorama CEA-2034 frequency response measurements.png


As noted on the graph, the on-axis (black) and listening window (dashed green) are mostly flat which is what we like to see in a speaker. This means it won't emphasize or de-emphasize some notes at the expense of others. Now, where you draw the line is tricky because there is a hump at 100 Hz or so. I usually opt to use 200 Hz as the reference point and there, we see extra low bass, some weakness in upper bass and some peaking at higher frequencies.

There seems to be little attempt to splice the tweeter and woofer response so that their radiation width match. As a result, the woofer keeps getting directional up to about 2 kHz but when the tweeter starts to take over, the width expands suddenly. This usually screws up the off-axis sound of the speaker but in this case, they important reflections tend to balance out:

X-LS Encore Kit DIY Speaker 2-way bookshelf spinorama CEA-2034 Early Reflections frequency res...png


So what showers your walls will be tonally close to the direct sound you hear from the speaker which is a good thing.

Putting the two together we get the tonality that you may hear in your room:
X-LS Encore Kit DIY Speaker 2-way bookshelf spinorama CEA-2034 Predicted In-room frequency res...png


Generally smooth and correct but with some ups and downs that could use tweaking. There is extra bass which mostly people will probably like but be mindful of it activating room modes more and cause booming sound (without EQ).

Impedance doesn't dip too low which should make it more amplifier friendly:
X-LS Encore Kit DIY Speaker 2-way bookshelf impedance and phase measurements.png


There is a slight kink in the response around 200 to 300 Hz which indicates some kind of resonance. It may be what we also see in the "waterfall" graph:

X-LS Encore Kit DIY Speaker 2-way bookshelf CSD Waterfall measurements.png


If these are due to the cabinet construction, then what you get in your build can be different. GR research measurements for example don't show the resonance around 1 kHz. This could be due to lack of resolution or proper testing on their part, or different cabinet. As always note that this measurement can be manipulated to show no problem or as much as you want!

Speaker Radiation Pattern
Ideally a speaker radiates sound in a predictable manner relative to direct sound. Due to directivity errors, we don't have that here:

X-LS Encore Kit DIY Speaker 2-way bookshelf Beamwidth measurements.png


If you follow the red line that shows when the response is down -6 dB relative to on-axis, the graph goes up and down a lot. So there is no uniformity which means how you toe in the speaker and the shape/reflectivity of your room can change the sound of this speaker fair bit. Your subjective results then may not match mine or the measurements.

In 3-D we see the same thing:

X-LS Encore Kit DIY Speaker 2-way bookshelf Horizontal Directivity measurements.png


Notice how the red region changes its width.

Vertically most 2-way speakers are bad but that doesn't seem to be a major issue in subjective listening:

X-LS Encore Kit DIY Speaker 2-way bookshelf Vertical Directivity measurements.png


You have more leeway with having the tweeter axis be below your ear height than above. If you go too far, you land in the non-red region meaning there is a lot of deficiency in that frequency region so you want to avoid that.

Speaker Distortion Measurements
I am only going to show Klippel distortion measurements and not Audio Precision in the hopes of having a life beyond reviewing speakers. :)

X-LS Encore Kit DIY Speaker 2-way bookshelf THD percent distortion measurements.png


At 86 dB SPL @ 1 meter, distortion is pretty much under control. Turn up the levels 10 dB though and the bass distortion naturally goes through the roof and the tweeter gets unhappy as well. But overall it is not too bad:
X-LS Encore Kit DIY Speaker 2-way bookshelf THD distortion measurements.png


As noted, and as I could hear during testing, the very low frequencies are severely distorted and don't sound anything like proper low notes so best to filter them out if you can.

EDIT: Forgot to post the individual driver responses:
X-LS Encore Kit DIY Speaker 2-way bookshelf Woofer Port Tweeter Frequency Response near-field ...png



Subjective Speaker Listening Tests
Out of the box, the XLS Encore sounded good. Yes there was a bit of exaggeration in bass which most of the time gave a warm impression to the sound (good). But there were occasional sharpness that would interfere (especially on female vocals). And there was a bit of muddiness/distortion. So I dug out the EQ tools and used the measurements to make a few corrections:

X-LS Encore Kit DIY Speaker 2-way bookshelf Roon EQ Correction.png


I first added Band 3 which gave the speaker a bit more air and clarity in upper bass.

Getting rid of bass distortion was hard as my standard filters would take away good bass (some of the distortion helps with sensation of bass). I eventually landed on the gradual filter as shown which nicely improved note separation and muddiness that was there before it. You would have to experiment in your room since that heavily impacts what is there.

Once there, I still could hear the occasional sharpness that would stand out depending on activation (i.e. content). I put in a dip where the peak was in on-axis around 7.2 khz and that tamed but did not fully remove it. More effort would be needed than me eyeballing it. :)

Once there, this was a very nice speaker and I started to listen to track after track with enjoyment. One of my delightful tracks is from Mary Coughlan's After the Fall album:

Mary Coughlan.jpg


I can only find this horribly recorded live version of it:


The X-LS Encore could play very loud even in mono configuration (how I test). It also managed to play the Dunwell's Animal track with its deep bass.

Conclusions
The GR Research X-LS Encore DIY KIT build as I tested shows very good performance which with a bit of EQ, rose up to near excellent. Yes there are some technical errors in directivity but otherwise, good attempt has been made to produce near neutral presentation which is what we strive for.

I am happy to recommend the GR Research DIY Kit (sans all the voodoo tweaks he offers).

Much thanks to Rick for building this speaker and sending it to me. I hope you use his services if you don't want to build it yourself.

-----------
As always, questions, comments, recommendations, etc. are welcome.

My handyman quit on me again after pulling weeds for a while and now I have to go do the rest. Did that yesterday and got so much dust and pollen in my nose that I have been sneezing non-stop. All because I can't afford to hire a more expensive and reliable worker! If you value my health, comfort and prettiness of our yard, I suggest you donate what you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

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TimW

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#5
Pretty great for a two way without a waveguide. I would bet money that the occassional sharpness Amir hear's is from the off-axis bump in the 2-4 kHz region.
 

napilopez

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#6
Good stuff! Looks like a neat speaker for a first build. Directivity also probably a bit better than it looks from the beamwidth, which I assume is normalized to the on-axis. There is some diffractions which gets resolved promptly off-axis, as shown in the listening window and @MZKM's graphs. Seems like 20 degrees off axis (no toe in) might be best as it's flattest and most similar to the wider angles.

Glad to see good performance, as I'd only really know GR Research for the more esoteric bits.
 

MZKM

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#7
the tweeter gets unhappy as well.
I saw that he states this is the Peerless T26SG, I tried looking it up and it turns out that it's made by Peerless of India, which is an offshoot of Peerless and their model name is "TL26SG". Too bad about the distortion, as the directivity is decently wide and measured performance (trying to ignore that baffle diffraction) looks pretty good. I do not know if the company is still in business as I can't find a working website, I did find another website selling them for ~$40/pair (Danny is ~$50/each), but no US shipping (many countries and US territories, but not the 50 states).
 

Rick Sykora

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#9
Thanks Amir. Like the ruler!

My listening experience was comparable. Sometimes I liked the bass, but other times seemed a bit boomy. I am just doing a quick check, so no attempt to eq. was made.

The resonance around 300 Hz was not quite as pronounced on the impedance measure as it is in the CSD chart. The 1200 Hz one appears to be a pipe resonance as I mentioned in the build thread. Can take a closer look when I complete the second speaker. :)
 
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Tks

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#11
Just thought of something that I don't know why I didn't think of prior. Why does no one 3D print cabinets? Especially big companies that can use simulations to verify internal designs especially...?
 
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amirm

amirm

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Thread Starter #13
Just thought of something that I don't know why I didn't think of prior. Why does no one 3D print cabinets? Especially big companies that can use simulations to verify internal designs especially...?
Besides the expense (it will take a long time to print and use a lot of material), it will be hard to finish. And may not have structural rigidity you need in a speaker.
 
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#14
I know Danny can be a bit polarizing, but I built his AV/3 towers about 15 years ago as my first DIY project and I still think they sound darn good today. His kits are good options for beginners, and some of his higher end open baffle kits do include a flat pack as an option.
 

Zvu

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#15
@amirm Shame we don't get to see individual measurements of the port and drivers as well as imd. I think it is important, especially with two way speakers since port resonances are almost always the problem as is imd. That shelf of delayed energy at 500Hz (resonance) visible on the waterfall plot could be port influence.
 

Tks

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#16
Besides the expense (it will take a long time to print and use a lot of material), it will be hard to finish. And may not have structural rigidity you need in a speaker.
What? Car parts are 3D printed. I wasn't thinking about 3D printing DIY polymers as your material. As for finishing, this is a problem how for companies charging thousands for speakers?
 
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amirm

amirm

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Thread Starter #17
@amirm Shame we don't get to see individual measurements of the port and drivers as well as imd.
Oh, sorry, I did measure the individual drivers:

 

Rick Sykora

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#18
What were your costs to built the pair? Like $80?
Probably a bit less as I used dampening material I had on hand, but there can be quite a bit of variability. The MDF was about $20 for me. Depending on how fancy you get with dampening, could add another $100 for GR's No Rez. I used open cell foam and it is about $15 for a sheet. Add a bit more for some poly fill ($7-$15). Need some glue and the Liquid Nails for the bracing. If you piecemeal the order, need a bit to cover shipping.

Unless I missed something, my estimate is about $60 as built.
 

Rick Sykora

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#19
Preference Rating
SCORE: 5.4
SCORE w/ sub: 7.6


Sensitivity: 84.4dB
Frequency response: +/-4.5dB 80Hz-20kHz
Decent score. :)

Sensitivity falls short of the webpage claim of 87 dB (or not, see Amir's comment later). I did not notice as I think the bit of boosted bass tuning makes it seem louder than the measurement would indicate. Not as surprised that the bass extension is not as low as claimed though.
 
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jtwrace

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#20
Probably a bit less as I used dampening material I had on hand, but there can be quite a bit of variability. The MDF was about $20 for me. Depending on how fancy you get with dampening, could add another $100 for GR's No Rez. I used open cell foam and it is about $15 for a sheet. Add a bit more for some poly fill ($7-$15). Need some glue and the Liquid Nails for the bracing. If you piecemeal the order, need a bit to cover shipping.

Unless I missed something, my estimate is about $60 as built.
You didn't use the No Rez?
 

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