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Ascend Sierra Luna Mini-Monitor Review

amirm

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This is a review and detailed measurements of the Ascend Sierra Luna small bookshelf 2-way speaker. It was kindly sent in by a member. The Luna costs US $588 each or US $1,148 for a pair.

The Luna is one of the smallest speakers I have measured:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker Review.jpg


Despite its small size, it is a very dense and heavy speaker. As you see it is front ported.

The back panel shows nicely machined in provisions for wall mounting which should come in handy for home theater Atmos (height) speakers and such:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker back panel binding posts hanger Review.jpg


The label says it is designed, engineered, and assembled in US. Does it mean it is manufactured fully in US? Or do they get the boxes from overseas and put the parts in it in US?

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 performed over 800 measurement which resulted in error rate of less than 1% throughout the range.

Temperature was 61 degrees F. 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. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.

Reference axis was the tweeter center.

Ascend Sierra Luna 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:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker Spinorama CTA-2034 frequency response...png


OK, this is a very jarring response. A woofer doesn't dance up and down so sharply by itself in a few hundred hertz? Fortunately I measure each driver at point blank and this tells us the problem:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker driver responses.png


See the port response in orange? It peaks (resonates) so much that its response actually exceeds that of the woofer creating those two "horns." It continues to mess up the woofer response even past that.

Strange to see the woofer response flattening post crossover point. Maybe it was also resonating? Regardless, if that was pulled down more , the combined response with tweeter would have been better.

Back to the spinorama, note that the efficiency to a few hundred hertz is only 80 dB or so. Indeed, I had to boost the signal by 6 dB compared to average of what I use for most speakers to get to 86 dBSPL output. Better have a lot of amplifier power. Don't be fooled by the small size of this speaker.

Early window response shows the same problems we see on-axis since port response is more or less omnidirectional:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker Spinorama CTA-2034 early reflections ...png


Combined we get what dominates the on-axis:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker Spinorama CTA-2034 predicted in-room ...png


Impedance is good bit higher than what is typical for 2-way speakers:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker impedance and phase measurements.png


Resonaces are visible by the way in kinks in the impedance graph (little ripples).

Distortion is naturally high at levels exceeding 86 dBSPL but I was surprised the speaker did not bottom out:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker relative distortion THD vs frequency ...png


Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker distortion THD vs frequency measureme...png


A highlight is the horizontal beamwidth:
Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker horizontal beamwidth measurements.png


Because the woofer is not much larger than the tweeter, their beamwidths blend together much better than in larger configurations.

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker horizontal Directivity measurements.png


Vertically is a mess as it typically is:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker Vertical Directivity measurements.png


Makes sure your ears are more or less at the height of the tweeter.

Ascend Sierra Luna Speaker Listening Tests
I tell you, marketing guys are right that the first impressions of a bright speaker are positive. Such was the case during the first few seconds: "oh listen to the details!" This changed though after a minute or so to: "man this is bright!" The sound was lispy as well but not super annoying. Just bright. So I pulled out the EQ:

Ascend Sierra LUNA REFERENCE RIBBON MINI-MONITOR Speaker Correction Filters.png


Despite the aggressive shelving filters I put in for high frequencies, the outcome was still a bit too bright but much more manageable.

Fixing the two port created resonances only made a subtle difference -- certainly less than what jumps out in the frequency response graph. A more accurate EQ may generate better outcome though than my eyeballing.

On a positive front, this speaker can handle a ton of power and get quite loud! Lack of bass response means that the little woofer does not bottom out -- not easily anyway. I was pretty impressed by this and should make the speaker more suitable for home theater applications.

Conclusions
Despite being very small, the Luna seems well built. Alas, poor port response wreaks havoc on the bass response. And elevated tweeter response makes the overall response too bright. Directivity is generally good so EQ seems to work well. Power handling is excellent due to not attempting to change the laws of physics and generate more bass than it is capable of.

As a perfectionist of course I want to see near ruler flat on-axis response at these prices. We don't have that here so score should be way down. I am not going to absolute bottom though as I hate distortion and lack of power handling in small speakers which the Luan does not suffer from.

Overall, I can't recommend the Ascend Sierra Luna but put it out there for people to optimize it with EQ to get respectable sound.

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

We are fortunate to live in a place where wild chanterelle mushrooms grow abundantly. My wife bought a basket recently:

Wild Chanterelle.jpg


Made a Chinese vegetarian stir-fry using our garden peppers and they were delectable! There is a farm near us where they would actually pick them but they had a ton of pine needles in them which made a pain to clean. The above were almost free of them which was great.

As always appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Attachments

  • Ascend Sierra Luna Spinorama.zip
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GimeDsp

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Thanks Amir!
I am not a fan of ribbons unless they are in a 3 way and limited to playing lower down.
It seems amazing that similar looking speakers to these can measure so much better. At least it looks good :)

With a front port and hanging brackets, I am wondering if the goal for these is rear surround speakers.

Here is the info from their website

"The Luna’s versatility is unmatched, crossed at 80Hz and used with a sub, they make terrific main's sounding nearly identical to our Sierra-2. The Luna’s are the perfect surround speaker with any of our ribbon speakers as fronts, or for someone seeking the ultimate desktop monitor. Using the integrated mounting hardware, the Luna’s become the perfect on-wall speaker. "

"crossed at 80Hz and used with a sub, they make terrific main's sounding nearly identical to our Sierra-2.
You would need to use an AVR's dsp and also need a ton of power?

"The Luna’s are the perfect surround speaker with any of our ribbon speakers as fronts"
This seems like the most likely fit. Would a mid range AVR have enough power for these to handle surround channel duty?

"Or for someone seeking the ultimate desktop monitor"
You would need a subwoofer and good DSP just to get close.
 
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GimeDsp

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I think your EQ didn't do much because of all the missing low end energy.
 

PeteL

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Thanks Amir!
I am not a fan of ribbons unless they are in a 3 way and limited to playing lower down.
It seems amazing that similar looking speakers to these can measure so much better. At least it looks good :)

With a front port and hanging brackets, I am wondering if the goal for these is rear surround speakers.

Here is the info from their website

"The Luna’s versatility is unmatched, crossed at 80Hz and used with a sub, they make terrific main's sounding nearly identical to our Sierra-2. The Luna’s are the perfect surround speaker with any of our ribbon speakers as fronts, or for someone seeking the ultimate desktop monitor. Using the integrated mounting hardware, the Luna’s become the perfect on-wall speaker. "

"crossed at 80Hz and used with a sub, they make terrific main's sounding nearly identical to our Sierra-2.
You would need to use an AVR's dsp and also need a ton of power?

"The Luna’s are the perfect surround speaker with any of our ribbon speakers as fronts"
This seems like the most likely fit. Would a mid range AVR have enough power for these to handle surround channel duty?

"Or for someone seeking the ultimate desktop monitor"
You would need a subwoofer and good DSP just to get close.
Well technically, they are naturally « crossed » around 80 Hz, so yeah, I’m not saying that they don’t benefit from DSP, but you can, and probably should, use a sub, and this would work even without a AVR. dpending of the setup
 

GimeDsp

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Well technically, they are naturally « crossed » around 80 Hz, so yeah, I’m not saying that they don’t benefit from DSP, but you can, and probably should, use a sub, and this would work even without a AVR. dpending of the setup
I've heard about some old sound study telphone companies did that showed if you are missing low end you can limit high/mid frequencies and a voice will still sound full, balanced and "normal". I wonder how that translates to music.
 

RayDunzl

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I've heard about some old sound study telphone companies did that showed if you are missing low end you can limit high/mid frequencies and a voice will still sound full, balanced and "normal". I wonder how that translates to music.

Set your low cutoff at 300Hz and your high cut at 3.4kHz to see...

That was the bandwidth for your old land line.

It occurpied a 64kbit channel, circuit switched (that channel and its bandwidth was all yours end to end), but was generally restricted to 56kbits/s to be compatible with T1 trunks.

With compression and a weak signal, a cell phone might drop as low as 5.15kbit/s, per this older article.

https://spectrum.ieee.org/telecom/wireless/why-mobile-voice-quality-still-stinksand-how-to-fix-it
 
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RMW_NJ

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I have a pair of these. I use them for rear surrounds in my home theater. The size is nice and they are extremely well built. They are also nice to look at, and made in the USA. With that being said, when I did test them out as mains I also found them to be quite bright. $1148 is a lot to spend on surround speakers, and if I had to do it again I probably wouldn’t.
 

GimeDsp

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I have a pair of these. I use them for rear surrounds in my home theater. The size is nice and they are extremely well built. They are also nice to look at, and made in the USA. With that being said, when I did test them out as mains I also found them to be quite bright. $1148 is a lot to spend on surround speakers, and if I had to do it again I probably wouldn’t.
At least it isn't a $5,000 rca cable.
 

napilopez

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Thanks Amir!

The directivity seems mostly controlled which is good. What's most peculiar and unfortunate about this is how dramatically different the lower half of the response is from the one on ascend's website.

1604210087893.png


Note how there are blips at 400, 800, and 1.2kHZ, but they are much smaller in amplitude.

I doubt ascend is actively trying to decieve anyone. My guess is a combination of smoothing and the low resolution in the lower midrange of quasi-anechoic measurements yielded a much prettier looking graph. And as Amir noted, I often find these lower midrange issues are less audible than they originally appear.

But goes to show the important of having measurements from different sources. Extensive measurements in isolation aren't quite enough.
 
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MZKM

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Preference Rating
SCORE: 1.3
SCORE w/ sub: 4.3

Sensitivity: 80.9dB (spec: 83dB)
Frequency response: +/-5.4dB 60Hz-20kHz ; +/-4.7dB 80Hz-20kHz


Spin graph now follows standard x:y axis ratio (1:1000 Hz = 50dB), done also in part due to Amir's post asking us to reduce image file sizes, datasheets will continue to use the "wide" format I have been using.
Spinorama (12).png
Horizontal Directivity (1).png
Horizontal Directivity Normalized (5).png
Vertical Directivity (1).png
Vertical Directivity Normalized (5).png
chart - 2020-11-01T124754.260.png



All graphs/data

What's most peculiar and unfortunate about this is how dramatically different the lower half of the response is from the one on ascend's website.
Comparison:

New Project (2).png
 
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MZKM

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Thanks Amir!

The directivity seems mostly controlled which is good. What's most peculiar and unfortunate about this is how dramatically different the lower half of the response is from the one on ascend's website.

View attachment 90599

Note how there are blips at 400, 800, and 1.2kHZ, but they are much smaller in amplitude.

I doubt ascend is actively trying to decieve anyone. My guess is a combination of smoothing and the low resolution in the lower midrange of quasi-anechoic measurements yielded a much prettier looking graph. And as Amir noted, I often find these lower midrange issues are less audible than they originally appear.

But goes to show the important of having measurements from different sources. Extensive measurements in isolation aren't quite enough.
Their website claims that each pair sold is matched to +/-1dB and each speaker comes with their unique frequency response measurement chart. Would be nice if the owner of these could find that and post it, if they still have it.
 

CDMC

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Those are bad measurements. So far Ascend has not lived up to the hype. I seriously considered a pair of these, I am glad I never purchased them.
 

MZKM

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Those are bad measurements. So far Ascend has not lived up to the hype. I seriously considered a pair of these, I am glad I never purchased them.
The 2EX has decent measurements, amazing for them to publish the Spinorama. Would love to see a Spin of the ~$2900 towers w/RAAL.

EDIT: Noticed the 2EX Spin uses a 60dB window, whereas the standard calls for 50dB, so it looks a bit more linear.

______

The label says it is designed, engineered, and assembled in US. Does it mean it is manufactured fully in US? Or do they get the boxes from overseas and put the parts in it in US?

From their site:
stunningly beautiful FEA and advanced 3d CAD designed Made-In-The-USA layered bamboo cabinet

I have no clue, but I would have assumed using FEA would have shown the port issues (turbulent air flow?).
 
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Ricardojoa

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It looks like front ported issue similar to salk wow.
Is gonna be hard to believe Dave will throw something like this out if he is aware of the issue.
Maybe the problem lies with the type of equipment used to design the speakers.

Can you do a measure with the port sealed to see if the issue persist?
 

YSC

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Seems the ribbon tweeters are usually not as behaved as a dome, I wonders are there ribbon that shows superior performance compared to a dome
 

BN1

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Hmm, I have these on my consideration list for next upgrade but now ... ??? On one hand, the brightness might be a blessing for my old, damaged hearing but on the other hand they seem not to have the SQ for my primary speakers. Looks like AA should take a page from Elac and bring out a 2.0 Luna with some improvements.
 
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