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:
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The back panel shows the somewhat utilitarian binding posts and the port:
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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:
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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:
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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:
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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:
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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:
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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:
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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:
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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:
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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.
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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:
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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:
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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:
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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:
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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.
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As always, questions, comments, recommendations, etc. are welcome.
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