Ascend Sierra Luna Duo Center/Main Speaker Review

[CDMC]

I went out to lunch with a friend yesterday, I got a burrito. I loved the first bite and hated the last bite. Our senses react differently all the time.
Just like Amir says speakers with hyped up treble can sound good and sell in the stores/demos but at home, after a while you get tired of them, fatigued.

Taco Bell? I swear most fast food has a 30-60 second window where it remains edible. Chick fil-a is the exception, you get a full two minutes.

 

[GimeDsp]

This is a speaker designed to be used with its ports open so that is how I tested it. It is not like it comes with any kind of plugs (which would be hard to do with rectangular ports). Bass response will also suffer. The near-field measurements have already shown the problem anyway. We don't need to spend an entire day re-measuring a speaker like this that in grand scheme of things, is not common.

Let's remember that external services charge $1000 to $1,500 for a measurement like I do. That is the opportunity cost when you ask me to keep measuring the same speaker rather than moving to another one.

It's taking all my self control to not bug Amir about what I sent in and about what I know is coming down the pike. But if everybody bugged him he couldn't get anything tested or any food cooked.

 

[GimeDsp]

Why would it matter? Unless someone purchased sight unheard and had no idea about it in the first place. Loudspeakers are the only component that allows for subjective sonic taste (other than fringe stuff like record players and cartridges). Either you like it, or you don't. Or you have mixed thoughts over it. If you like it, then how can a measurement change that? Possibly one would like something better that measured closer to 'the ideal'-- I guess one could argue that. But the only way with loudspeakers is to live with them in your living room for a couple of weeks, get used to the sound, and then make a determination.

The problem anymore is that there are fewer and fewer local dealers with a selection for in-store comparison, and then allow in-home trials for a week or two. Typically, at least today and for many brands, one must buy something mail order, have it shipped to them, and if they want their money back they must pay return freight, which with loudspeakers can be a sizable expense.

If you are looking for a small two-way 'monitor' speaker it's usually easier, because most 'guitar stores' have a dozen brands you can go listen to, take home and audition. For 'high end' type home loudspeakers it's difficult.

The problem as I see it is dealing with these smaller 'boutique' makers. My guess is that no one has any idea what they sound like before they purchase. Most audiofools at least have a general idea what a B&W, JBL, Klipsch, Polk, or other established manufacturer's speakers sound like. You get into Ascend Lunar Module territory and how would you even begin to know?

Here is why it matters for these speakers.
They are marketed for

Front mains
If used with auto correction or DSP via AVR some of the issues may be coved up. If used in a bad room then room issues may mask bad performance

Desktop
If used on a desk then comb filtering from the desk and a single listening postion may mask the issues of poor listening window.

Rear surrounds
Lack of full range, musical content will hide poor performance if they are placed here to begin with.

So you can see that you may ONLY realize and hear the bad perfomance quickly if they are set up as front mains, in a room with a high level of direct sound vs reflected. How many people are going to ge these, then try them in all different places?

 

[GimeDsp]

Taco Bell? I swear most fast food has a 30-60 second window where it remains edible. Chick fil-a is the exception, you get a full two minutes.

Just a local place that's been around for 30 years.

 

[GimeDsp]

The problem I see here is that Ascend's measurements do not correspond to the product delivered. As several speakers designers have pointed out the issues that both Lunas have don't require specialized equipment to discover, they are readily apparent with normal measurements. This leaves two possibilities on the part of Ascend either 1) they are so incompetent they don't have any clue how to measure basic speaker performance, or 2) they fudged their results to make their product look good. Given Dave's year of updates and claims of multiple design revisions and prototype custom drivers, either he was just weaving a tale and not actually designing and measuring the speakers, or 2) knew of the issues and played with the measurements Ascend posted to make them look better. Both possibilities are misleading.

It seems to me that if you are a small manufacture and you are selling your speakers based on objective measurements the path forward in the future is going to be to pay the $1,000 to 1,500 to have your final product tested by an independent third party. While not cheap, even for a small manufacture it provides verifiable results for comparison.

With a supportive base I am sure they can crowdfound final testing-BUT they may think it makes them look bad.
Or they can cut Amir in and bribe him with a lifetime supply Pink Panthers.
Either way, AA is in a tough spot here.

 

[CDMC]

With a supportive base I am sure they can crowdfound final testing-BUT they may think it makes them look bad.
Or they can cut Amir in and bribe him with a lifetime supply Pink Panthers.
Either way, AA is in a tough spot here.

They are. I have to commend them and their members on their forum in taking a measured approach to looking over why the results are different.

 

[Robbo99999]

Oh my lord, another Halloween speaker!!

 

[tktran303]

IME, 600Hz is usually of the upper limit, depending on the size, aiming and distance of mic from DUT (which makes aiming less of a concern as you are >> away from the DUT).

If I measure a port in the nearfield or via ground plane, then how does one visualises all those resonances out past 700Hz or 1KHz?

 

[richard12511]

The problem I see here is that Ascend's measurements do not correspond to the product delivered. As several speakers designers have pointed out the issues that both Lunas have don't require specialized equipment to discover, they are readily apparent with normal measurements. This leaves two possibilities on the part of Ascend either 1) they are so incompetent they don't have any clue how to measure basic speaker performance, or 2) they fudged their results to make their product look good. Given Dave's year of updates and claims of multiple design revisions and prototype custom drivers, either he was just weaving a tale and not actually designing and measuring the speakers, or 2) knew of the issues and played with the measurements Ascend posted to make them look better. Both possibilities are misleading.

He mentioned in his post on the Ascend forums that he was aware of the port issues during design, but their measurements didn't show them to be as big of a problem as shown here.

"we use tried and true MLSSA systems, so there may be differences as to how port output is summed in the near field, resolution differences, or the NFS system might be sending a lot of low frequency information to the speaker at a high amplitude – thus exciting port resonances to a higher degree"

It seems to me that if you are a small manufacture and you are selling your speakers based on objective measurements the path forward in the future is going to be to pay the $1,000 to 1,500 to have your final product tested by an independent third party. While not cheap, even for a small manufacture it provides verifiable results for comparison.

Or buy a Klippel NFS, as that would allow you to freely measure prototypes and ideas to see how well they work. I wonder how much $100,000 is to a company like Ascend? Genuine question. Personally, I'd be more likely to buy from a company if I knew they had an NFS.

 

[hardisj]

If I measure a port in the nearfield or via ground plane, then how does one visualises all those resonances out past 700Hz or 1KHz?

In my case it is different because I use the ground plane to provide a reference measurement to Klippel's ISC module which then allows me to use indoor measurements and build a room correction curve to remove room effects.

But, for most people what you'll have to do is get the absolute best window you can in the free-field measurement. I'd shoot for at least 200Hz resolution. Obviously, the higher, the better. Combine that with the ground plane measurement up to the highest frequency you can from the GP measurement. You can still use the GP to eyeball things and if your aiming and conditions are good enough then maybe you can get accurate response even higher in frequency. But IME that's really only the case for smaller speakers. Once you go larger you have issues with getting the mirror image and aiming which effects the response in the upper midrange and beyond.

Start with the free field response first. Get it as reflection free as possible. That will help you better determine just how high in frequency you can go for your GP measurements and still retain accuracy. Make sure to have your speaker flat on the ground (not on a turntable, as this will alter the response >400Hz) and tilted as necessary to get the axis aligned with the microphone (i.e., the tweeter aimed at the mic). Also make sure to use a hard surface with plenty of area around you. A parking lot helps. Grass will kill the accuracy above 400-600Hz as well based on my experiments. It's really trial and error with some give and take. But you should be able to get very good measurements with (relatively) high resolution with time and patience.

 

[amirm]

Psychoacoustics. Perhaps there was expectation bias or placebo helping you to enjoy it before you knew it measured terribly. Ascend is an ID company that sells many speakers based on the fact that they publish superb looking measurements. I could definitely see where expectation bias(based on the published measurements) could trick one's brain into enjoying a sound that they don't actually enjoy based on pressure waves alone. Once that placebo is removed(by ASR), the sub-optimal pressure waves take over the brain's impression.

I think another explanation is people learning what is good sound, and what is bad. To the extent one buys into the description of a speaker from a company or other vocal promoters, then realizing with measurements that the sound is not good and then focusing on those deficiencies and realizing the same, is a good thing. We all try to learn every day what it means to get better gear. But getting our ears trained this way is super difficult. Measurements provide a training tool just like a digital camera does by showing you an imagine immediately so you realize if you took a good or bad picture.

 

[hardisj]

I think another explanation is people learning what is good sound, and what is bad.

Bingo.

I catch flack for some of my reviews when I say something is a poor performer. The most common retort is "it sounds good to me". That usually equates to "ignorance is bliss".

 

[amirm]

Or buy a Klippel NFS, as that would allow you to freely measure prototypes and ideas to see how well they work. I wonder how much $100,000 is to a company like Ascend? Genuine question. Personally, I'd be more likely to buy from a company if I knew they had an NFS.

We don't know their sales volume nor profit margin so very hard to answer. The other thing is the value of measurements to their sales. Seems like their customers care more than average so that is likely a good motivation.

I do know this: if I were designing speakers, the Klippel NFS would be a gift from heaven! The amount of optimization you can do is incredible. Every few hours you could get another snapshot. You can also learn so much more about acoustics by modifying and iterating.

And it is not just performance but cost. You could have clear data to decide which factors matter the most, and what don't.

Our testing has led to a number of companies buying Audio Precision analysers. Prior to that, they would bulk at $28K price of that but not now. They much rather optimize the design themselves than waiting for me to test and find them!

 

[ctrl]

If I measure a port in the nearfield or via ground plane, then how does one visualises all those resonances out past 700Hz or 1KHz?

Described it a few posts ago.
The resulting overall frequency response is only valid up to about 300-400Hz (in most cases, above this frequency the FR is influenced by chassis shape, size, edge diffraction, ...), but this method is sufficient to approximately determine the effects of BR-port resonances.

More details on how to get the overall frequency response, see Arta-Handbook page 127.

 

[detlev24]

[...] Or buy a Klippel NFS, as that would allow you to freely measure prototypes and ideas to see how well they work. [...]

While it is a great tool that would save a lot a time due to its automatism; a Klippel NFS is certainly not required to build superb loudspeakers.

REW can measure and display wall reflections and their intensity, as it is quite easy to predict where they come from (by a mathematical approach or simpler, by using a mirror). qSpin etc. - not a problem!

Even the entire bass region can be measured reasonably well without investing a lot of money, as Data-Bass and others show consistently.

I guess what makes a noticeable difference is the philosophical approach a manufacturer follows and hence, how much time and effort is invested in the pure science of building, or at least aiming for, "flawless" products.

 

[DuncanTodd]

Putting aside the design flaws indicated on this review, one of the things I like about the speakers reviews here, is the subjective hearing tests. It leaves aside the amplitude response "bench racing" and focuses on real life use, listening to something. I've seen several reviews with both aspects contradicting each other to some degree at least.

 

[tktran303]

Described it a few posts ago.
but this method is sufficient to approximately determine the effects of BR-port resonances.

This is what I think I’m understanding, or misunderstanding.

Is measuring a rear firing port or PR, and getting its “approximate FR up to 1-2KHz”, at a resolution that’s not high enough, to determine how it contributes, or affects. with it’s out of phase behaviour, to the frontal hemisphere response of the woofer?

Amir NFS results seems to show all the warts in the region of the port/PR and the woofer, that I don’t see from the usual near field/far field merged or blended response when speakers are typically designed without an anechoic chamber

 

[MZKM]

I think another explanation is people learning what is good sound, and what is bad.

I remember when Beats first started selling headphones (2008?) and my grandfather gifted me the Beats Tour IEM ($150 I think; and back when they partnered with Monster cables) for my birthday, I remember having friends try them out and their surprised faces when they heard that bass (everyone back then just had those free Apple Earbuds or the even cheaper Android equivalent, no IEMs). However, then I actually got some “audiophile” IEMs and that changed everything.

So yeah, better than what the average person has, but in the niche crowd that is audiophiles, it isn’t even considered for purchase.

 

[GimeDsp]

There are MANY methods they could use to get a good look at what the low end and port are doing. Take your pick, there are MANY they could do without any extra $$$ investment in gear.

 

[hardisj]

Here's a visualization of what I mean when I say the quasi-anechoic method often results in a resolution not suitable to show resonances in the midrange (and below). This is the Buchardt S400 I measured. Amir measured the same model (not the exact same speaker) and his results also showed this high-Q peak/dip around 500Hz.

In red is the response when I set the IR time to filter out anything beyond 4ms, which gets me down to about 250Hz. This is pretty typical of most measurements not performed in an anechoic chamber.

In black is the full anechoic response generated using Klippel's ISC module paired with a ground-plane reference measurement and my indoors measurement.

As you will see, the red line does not come close to showing the high-Q anomalies in the midrange. They are there. The resolution is just too low for the points to fill in and you are instead left with a smoothed over response compared to the anechoic.