Ascend Sierra-1 V2 Speaker Review

[hutt132]

I have the Sierra-2EX V2 pair and they've been my end game speakers. Would love to see them measured here one day.

 

[Beave]

Are you trolling, or did you just misunderstood my post ? I wrote that measurements are only a part of the equation and then you reply in slightly different words that "different people have different tastes and that rooms and personal preferences play a big role". I am guessing English is not your first language ? If it was, you would know that you literary confirmed what I wrote to begin with. Have a great Easter holiday

LOL

 

[Bruce Morgen]

I don't see anything to fault here. People needing high output and low distortion in the bass/midbass region should obviously consider larger monitors, or take advantage of the displacement and sensitivity benefits of towers.

Yeah, I see some of its major competitors around the $1k/pair price point being the better active monitors in that range, because it's hard to imagine a better passive two-way on that sort of budget, especially if one already owns a suitable amp that can deliver adequate "juice" -- which is a non-trivial consideration on account of its relatively high impedance and low sensitivity.

 

[Beave]

Yeah, I see some of its major competitors around the $1k/pair price point being the better active monitors in that range, because it's hard to imagine a better passive two-way on that sort of budget, especially if one already owns a suitable amp that can deliver adequate "juice" -- which is a non-trivial consideration on account of its relatively high impedance and low sensitivity.

Am I misreading,, or are you implying the high impedance is a problem?

 

[jhaider]

Your assumption on the design goal for this speaker is wrong. As discussed in detail on our forum with its release, the goal of this speaker was as even and as neutral a sound power response as we could achieve. As you know, sound power represents the total radiation of the speaker and, in my professional opinion, best represents a speaker’s overall neutrality.

Well...let’s put a pin in that until the the end of this post (and pls fix the misleading math fallacies described therein).

Regardless, everything I wrote above is equally applicable to sound power as PIR.

Can you cite to published preference research that backs up this position, or is it mere assertion? If memory serves, the business rationale for the studies that led to the "Olive score" was to prove Consumer Reports wrong for ranking speakers based on sound power - a ranking that disfavored speakers consistently preferred in subjective blind listening tests.

I do know of one study that tends to contradict your above-stated position, and is consistent with my general experience as well as Amir's subjective listening impressions of your loudspeaker as relayed in the OP here: the Olive "curve drawing" study cited in Sound Reproduction (3rd ed, section 5.7.3, at 140 on the Kindle version) wherein trained listeners' impressions of the tonality of a set of loudspeakers most closely tracked their on-axis and listening window average frequency response and not the sound power.

To accomplish this, it meant precisely matching the directivity of the woofer and tweeter at crossover.

Neither Amir's measurements nor the comprehensive measurements you publish on your website (props for doing that, BTW - wish every manufacturer was so conscientious) support the claims of directivity matching you make throughout the quoted post. Rather, the measurements show a telltale dispersion disruption in the horizontal beamwidth in the midwoofer-tweeter transition region - narrowing through the top of the woofer's passband followed by excess energy as the tweeter comes in..

Doing so without a waveguide on the tweeter is an extremely difficult task, but it is possible as these measurements clearly indicate. It was also our goal to offer wider horizontal dispersion, something a waveguide limits.

The issue here is your speakers do in fact employ a waveguide. The issue is generally never waveguide vs. no waveguide (unless one device being discussed has naked drivers suspended by their wires), but rather the dimensions and geometry of the waveguide employed. Your chosen waveguide just happens to be the most basic possible geometry - a flat plane with 90 degree corners.

That notwithstanding, the above-quoted language is obsolete thinking. See, e.g. https://purifi-audio.com/blog/tech-notes-1/spk16-reference-design-12


If you claim the subject speaker has wide dispersion (which it does, over a limited bandwidth, followed by significantly narrowing over top two octaves) - what do you call this?

I call it “a tweeter loaded into a waveguide.”

Let’s compare the sound power response and ERDI of the S1V2 with the Revel M105, which takes full advantage of a waveguide. Which sound power response is the more linear in the crossover region? Which ERDI has less directivity error?

I'm not interested in playing the compare x to y commercial finished product game. Please re-read the last line of my previous post. We’ve already established that one can degrade the key metric of on axis/listening window response in the crossover transition region so as to balance out the excess off-axis energy.

(And before anyone complains about hypocrisy re my earlier paragraph, that's a measurement of a prototype tweeter/phase plug/waveguide unit by Purifi, a raw driver and amp module supplier, not a commercial finished product, such as e.g. a Grimani or B&O speaker.)

You mention tinkering to achieve the textbook PIR. How exactly?

By degrading the on axis response / listening window to compensate for dispersion disruptions, i.e. game the averages by balancing the overall energy in the room to be even even though none of the individual components are exemplary. Just as you did here.

The textbook PIR was not and was never the goal, it is the direct result of an incredible amount of R&D to get a textbook sound power response, which translates to ideal overall neutrality.

If true, you may want to recalibrate your marketing. Run a search on this page for "sound power:" https://ascendacoustics.com/collect...ducts/sierra-1-v2-pair?variant=41419225038902

0 hits.

Yet the page closes with this section (emph. added):

"*Note: Our exclusive Off-Axis Estimated In-Room Response measurement is a critical performance metric. It is an accurate comparison of the differences a listener should expect to hear sitting at different off-axis angles from the speaker; on-axis, +/- 10 degrees horizontally, +/- 20 degrees horizontally and +/- 30 degrees horizontally.

This is a modern and more accurate prediction of in-room speaker performance at different listening angles compared to a simple off-axis measurement graph. This measurement graph accounts for both direct sound and indirect sound and requires thousands of individual off-axis measurements that are then processed through complex algorithms to derive the results. In comparison, an off-axis measurement is just a single response measurement that does not account for the actual directivity of the speaker and is not representative of what we actually hear.

This measurement clearly shows the remarkable off-axis response of the Sierra-1 V2. There is less than 1/2dB of deviation between the different off-axis positions and this is based on accepted science determining what the listener will hear from this speaker in a typical listening environment."

N.B. You should wordsmith that final paragraph because it's inaccurate and misleading as written. An average says nothing about the distribution of the underlying values making up that average.

 

[Bruce Morgen]

Am I misreading,, or are you implying the high impedance is a problem?

Read a few of Amir's amp reviews -- virtually every one reveals that amp power goes significantly up as load impedance goes down. This means one has to make sure the amp under consideration can deliver sufficient power in the context of the load impedance, and if it can't provide enough power to reach ones intended/preferred SPL -- which is where the speaker's "relatively low sensitivity" is another factor -- then it's not a good match for your use case and thus "a problem."

Make sense now?

 

[Beave]

Read a few of Amir's amp reviews -- virtually every one reveals that amp power goes significantly up as load impedance goes down. This means one has to make sure the amp under consideration can deliver sufficient power in the context of the load impedance, and if it can't provide enough power to reach ones intended/preferred SPL -- which is where the speaker's "relatively low sensitivity" is another factor -- then it's not a good match for your use case and thus "a problem."

Make sense now?

No, actually it doesn't. You seem to be implying that low impedance in a speaker is a good thing because many (or most) amps can supply more power into low impedance loads. But that thinking is exactly backwards. Lower impedance loads suck more current from the amp. They *require* more power for the same volume level. That's a bad thing, not a good thing. A higher impedance means less current is sucked from the amplifier, meaning less power is needed (assuming voltage sensitivity is the same).

If you have two 81dB/2.83V/1m sensitivity speakers, and one is a perfect 4 Ohm load (flat with no reactance), and the other is a perfect 8 Ohm load (flat with no reactance), then they both are going to output the same volume for a given voltage output from your amp. But the 4 Ohm speaker is going to require twice the current, meaning it needs twice the power to produce the same output. That means it makes the amp work a lot harder. That's the opposite of what you want.

 

[Bruce Morgen]

No, actually it doesn't. You seem to be implying that low impedance in a speaker is a good thing because many (or most) amps can supply more power into low impedance loads. But that thinking is exactly backwards. Lower impedance loads suck more current from the amp. They *require* more power for the same volume level. That's a bad thing, not a good thing. A higher impedance means less current is sucked from the amplifier, meaning less power is needed (assuming voltage sensitivity is the same).

If you have two 81dB/2.83V/1m sensitivity speakers, and one is a perfect 4 Ohm load (flat with no reactance), and the other is a perfect 8 Ohm load (flat with no reactance), then they both are going to output the same volume for a given voltage output from your amp. But the 4 Ohm speaker is going to require twice the current, meaning it needs twice the power to produce the same output. That means it makes the amp work a lot harder. That's the opposite of what you want.

The hypothetical comparison of two speakers that perform identically aside from nominal impedance isn't relevant here and neither is how hard an amp has to work at long as it operates within its ratings. We're talking about an actual speaker and deciding whether a particular amp is up to driving it to the desired/preferred SPL. Relatively high nominal impedance isn't problematic per se -- unless the amp in question can't provide the needed power at that impedance, even if it could provide more enough power for that hypothetical otherwise-identical speaker with half that impedance. Nominal speaker impedance is neither a good nor a bad thing, but it must be considered when selecting an amp. IOW, your word *require* applies AFAICT.

 

[Beave]

I'm afraid I'm not explaining it well enough. My example is quite relevant, if you understand my point. When selecting an amp for speakers, one is concerned about low sensitivity (like these), because they will require a lot of voltage to get loud; and one is also concerned about low impedance, because they will require a lot of current to get loud. One is not concerned with high impedance.

A low sensitivity (db/2.83V) speaker is a concern because it will require a large voltage swing from the amp to play loud. An amp could run into voltage clipping in that scenario if it isn't sufficiently capable.

A low impedance for a speaker is a concern because it means any amp driving it will be taxed with outputting a lot of current, thus stressing the amplifier (heating up the output transistors and taxing the power supply stores).

Maybe somebody else here can explain this better than I am doing?

added: Amps are (usually) *voltage* amplifiers. They are provided a voltage by the source, and they amplify that voltage to power the speakers.

 

[aarons915]

I'm afraid I'm not explaining it well enough. My examples is quite relevant, if you understand my point. When selecting an amp for speakers, one is concerned about low sensitivity (like these), because they will require a lot of voltage to get loud; and one is also concerned about low impedance, because they will require a lot of current to get loud. One is not concerned with high impedance.

A low sensitivity (db/2.83V) speaker is a concern because it will require a large voltage swing from the amp to play loud. An amp could run into voltage clipping in that scenario if it isn't sufficiently capable.

A low impedance for a speaker is a concern because it means any amp driving it will be taxed with outputting a lot of current, thus stressing the amplifier (heating up the output transistors and taxing the power supply stores).

Maybe somebody else here can explain this better than I am doing?

added: Amps are (usually) *voltage* amplifiers. They are provided a voltage by the source, and they amplify that voltage to power the speakers.

I think a simple way of saying it is that the higher the impedance the fewer the watts are required since amps are constant voltage devices. I don't think it even matters for the vast majority of people since we really don't listen that loud.

 

[dtaylo1066]

Seems like 1K of goodness to me.

 

[MaxBuck]

Really wonderful speaker, especially for the price. Ascend deserves mucho kudos for this effort. They have some good people, obviously.

 

[dzerig]

It would be useful to have data for the use with a subwoofer and cutting off the frequency response at say 80 hz and 120 hz to see how it helps at 96 db.

 

[Beave]

It would be useful to have data for the use with a subwoofer and cutting off the frequency response at say 80 hz and 120 hz to see how it helps at 96 db.

Amir doesn't do multitone distortion, only harmonic distortion. Erin did the measurements you are looking for (well, at least the 80Hz cutoff).

 

[Bruce Morgen]

I'm afraid I'm not explaining it well enough. My examples is quite relevant, if you understand my point. When selecting an amp for speakers, one is concerned about low sensitivity (like these), because they will require a lot of voltage to get loud; and one is also concerned about low impedance, because they will require a lot of current to get loud. One is not concerned with high impedance.

A low sensitivity (db/2.83V) speaker is a concern because it will require a large voltage swing from the amp to play loud. An amp could run into voltage clipping in that scenario if it isn't sufficiently capable.

A low impedance for a speaker is a concern because it means any amp driving it will be taxed with outputting a lot of current, thus stressing the amplifier (heating up the output transistors and taxing the power supply stores).

Maybe somebody else here can explain this better than I am doing?

added: Amps are (usually) *voltage* amplifiers. They are provided a voltage by the source, and they amplify that voltage to power the speakers.

WTF would anyone be concerned about "taxing" gear as long as it's operating within its specs? If such "taxing" breaks the gear or wears it out before its time, then it's flawed gear. Period.

Let me simplify the issue from an amp buyer's point of view: an 8 ohm low-sensitivity speaker has been determined to require 80 watts to reach the desired SPL and the amp under consideration is rated at 100 watts into 4 ohms, but only 60 watts into 8 ohms. Should the buyer choose that particular amp for that speaker or move on to an amp that has a 100+ watt rating at 8 ohms? Is it perhaps misguided to use wattage numbers to make such a decision because something else is what really matters? Perhaps I have disastrously oversimplified this decision making process, but I have a hunch it's what most non-technical folks do: they determine the wattage a speaker requires for the desired SPL, and then choose an amp rated to deliver that wattage or more at the speaker's impedance. I'm sure folks would appreciate a more suitable amp selection procedure -- any and all recommendations welcome!

 

[Beave]

Actually, yes, it's a bit of a problem with amplifier measurement and specification. Everything is given in watts, and customers think in terms of watts. It can be misleading. What is really happening is that the amp is producing voltage at its output terminals, and the load impedance of the speaker determines the current being drawn. The wattage being output is a secondary characteristic - determined by the voltage and current. It would be much easier if amps were spec'd and tested in terms of how much voltage they can produce into different loads before clipping. But for decades, it has all been about watts, for both speaker specs and for amplifier specs. So it's probably a pipe dream to think it's going to change.

Speakers are sometimes quoted at how loud they are for a given wattage, but it's much more precise to spec them based on how loud they are for a given voltage.

As for concern about "taxing" gear, it matters. More current leads to more heat. Heat builds up and leads to the amp shutting itself down when its thermal detectors are tripped. Or the transistors and caps themselves have a reduced lifespan because of the heat.

Yea, those things are well known by designers and accounted for. That's how you end up with giant heatsinks in amplifiers. And sometimes fans. And those giant heatsinks can be quite expensive. And the giant caps in the power supply are costly too, and they are needed for amps (well, except class D) that can provide a lot of current.

 

[Bruce Morgen]

Actually, yes, it's a bit of a problem with amplifier measurement and specification. Everything is given in watts, and customers think in terms of watts. It can be misleading. What is really happening is that the amp is producing voltage at its output terminals, and the load impedance of the speaker determines the current being drawn. The wattage being output is a secondary characteristic - determined by the voltage and current. It would be much easier if amps were spec'd and tested in terms of how much voltage they can produce into different loads before clipping. But for decades, it has all been about watts, for both speaker specs and for amplifier specs. So it's probably a pipe dream to think it's going to change.

Speakers are sometimes quoted at how loud they are for a given wattage, but it's much more precise to spec them based on how loud they are for a given voltage.

As for concern about "taxing" gear, it matters. More current leads to more heat. Heat builds up and leads to the amp shutting itself down when its thermal detectors are tripped. Or the transistors and caps themselves have a reduced lifespan because of the heat.

Yea, those things are well known by designers and accounted for. That's how you end up with giant heatsinks in amplifiers. And sometimes fans. And those giant heatsinks can be quite expensive. And the giant caps in the power supply are costly too, and they are needed for amps (well, except class D) that can provide a lot of current.

All the amplification in my system is Class D, so nothing "giant" is involved and I can safely ignore any "taxing" effect. In fact, the passive speakers I use for ambience/surround effect are rated at 8 ohms, so I really have no skin in this game.

I'm going to take a chance and guess that you agree that the amp selection procedure I described would be adequate in the vast majority of use cases, so my original comment still comprises good advice: get an amp rated at least for the wattage your speaker requires for the SPL desired given that speaker's nominal impedance. Everything you've stated is clearly correct, including the fact that "it's probably a pipe dream to think it's going to change" -- so folks have to work with what we can readily get from spec sheets and/or measurements: wattage, SPL, sensitivity, and load impedance.

 

[Karmacoma]

At that price it looks like a winner.
Kudos to Ascend Acoustics!

 

[JakeK]

WTF would anyone be concerned about "taxing" gear as long as it's operating within its specs?

OK. I'm going to try.

The amplifier supplies voltage and current. The ideal is that the voltage at the speaker terminals is a perfect copy of the shape of input signal to the amp but at proportionally higher voltages, regardless of current (amps).

What is taxing about low impedance in a speaker is that lowering impedance or resistance increases current for the same voltage and draws more power. Why is that a problem? Higher current means that the resistances and impedances within all the components in the amp will draw more power as well and cause the voltage to reduce or droop at the speaker. Every component in the chain will draw some power and drop some voltage in proportion the amount of current. This changes or distorts the shape of the sound signal at the speaker.

Ideally the amp will have a vanishingly small internal impedance or resistance compared to the speaker impedance meaning that the amplified voltage at the speaker would be perfect, but this is not possible. Amplifier designs do various things to combat this problem by having reserves that can provide large amounts of current and power at the precise instant of demand but nothing is perfect.

Low impedance in a speaker is bad for amplifiers in other words and will increase distortion. This is true even if the current and power draw is within the capability or specs of the amp.

Higher impedance in the speaker means less distortion of the signal or voltage in the amplifier. That's physics. I hope this helps!

 

[Endibol]

This is a review, listening tests, EQ and detailed measurements of the Ascend Acoustics Sierra-1 V2 bookshelf speaker. It is on kind loan from a member and costs US $998 for a pair ($948 on sale).
View attachment 359703
The finish is nice enough. The cabinet feels quite heavy for its size and especially in the front indicating beefy low frequency woofer. I do wish the grill was magnetic though rather than plastic tabs that are more delicate. I did my testing without it and would have been nice to not see those holes.

Back panel put a big smile on my face:
View attachment 359704
See the "NFS Optimized" tag! A couple of years ago I tested an Ascend speaker and found the performance wanting. Needless to say, the company owner/designer, Dave, was not happy. But instead of taking his anger on me, he reached out to Klippel to learn more about the Near-field Scanner I had used to test his speaker. He quickly ordered one and started to revamp his speaker designs. We have seen an example of this in electronics area and benefits it brings to the company and its buyers. Such is happening here in speaker design.

It was with nervous fingers and ears that I went into this testing. Yes, there is another set of measurements out there but my testing differs enough to merit testing a user purchased sample. So here we go.

FYI, I ran the measurements by Dave (company designer) last night and they correlate very well with their internal measurements. There is a tiny bit of deviation in bass well below response of the speaker which is not material. And at any rate, I measured the speaker at 59 degrees F which tens to damp bass response a bit.

If you are not familiar with the measurements you are about to see, I highly recommend you watch my video on understanding speaker measurements:

Ascend Sierra-1 V2 Speaker Measurements
Let's start with our speaker frequency response measurements as usual:

View attachment 359706
On axis response is quite good with only small variations here and there which my higher resolution scan brings out more than other measurements. We see a couple of small resonances below 1000 Hz (see below for cause). And a dip around 3 kHz. But really, these are very minor. What is very remarkable is the early window response in dashed blue. It is so smooth and nice after 900 Hz. We can see that in detail in early window response:
View attachment 359708
This is what you get with closed loop measurements and excellent engineering folks! All the reflections so nicely sum together, likely better than any speaker I have measured! This means the speaker will be very room friendly and easy to place. To wit, putting everything together we get an excellent predicted in-room response:
View attachment 359709
Amazing that this is achieved in a passive speaker without DSP!

Close-in measurements of the port and driver show resonances very well suppressed:
View attachment 359710
Putting on our hyper scrutiny hat, we do see minor contributions from the port resonances in on-axis response. But as judgements go against countless other bookshelf speakers, this is excellent showing.

Sensitivity of the speaker is low side to get that deeper, flat extended response and that brings out issues with the woofer not being able to handle high SPL very gracefully:
View attachment 359711
View attachment 359712

But keep that thought when I evaluate this in listening tests.

I showed this tri-power sweep in the last speaker review and folks liked it so I repeated it here. Alas, 102 dBSPL was causing the speaker to nearly blow its mind so it is well outside of its design envelop:
View attachment 359713
The difference between 86 and 96 is too minor to be of concern.

Horizontal directivity is fairly well control especially considering that we don't have a deep waveguide:
View attachment 359715
The lack of waveguide is what allows the wider directivity which again, I will evaluate in listening tests.

View attachment 359716

Vertical directivity has the typical issues we see in non-coaxial designs so nothing of specific worry here:
View attachment 359717


Impedance is unusually high in this day and age, making the speaker an easier drive although lack of sensitivity means you still need lot of power on tap:
View attachment 359714

Here is our waterfall and step responses:
View attachment 359718
View attachment 359719

Ascend Sierra-1 V2 Listening Tests and Equalization
As I noted at the outset, I was a bit nervous about going into this aspect of the listening test. Would I like a speaker that is fully optimized with NFS in listening tests? Would I be biased to like it regardless? I always start with my female tracks and here, the response left no room for complaining. Sound was balanced with no aspect of the speaker standing out until a bass note activated a room mode which I corrected with my usual 105 Hz filter. I then listened some more. Am I liking this sound? Answer was, that it was pleasant but not exciting. Measurements showed that speaker was optimized for off-axis and PIR more than on-axis. Let's see what happens when we reverse this situation and flatten on-axis:
View attachment 359720
I started with Band 2, filling that small bass dip. That very nicely brought female vocals forward. That encouraged me to then pull down the two port resonances. Yes, the filter strength is very low but it was enough to change the character of the upper bass. Once all the filters were in place, I performed AB tests and boy, I really, really liked the results with this EQ. We are talking about subtle differences but the sound was more open and clarity was improved.

What was really nice was the spatial qualities of the speaker. Its wide directivity meant it projected a large halo around the single speaker I was listening to. This, combined with the tiny tweaks above made for stunning presentation at times. Some of my reference tracks sounded so good that my jaw fell on the floor!

I was expecting to hear distortion at elevated volumes but this did not materialize. Even at elevated playback levels where I could see the woofer moving back and forth, I could not detect any degradation.

The problem area with respect to distortion is in deep sub-bass region. Most bookshelves won't bother to play this range. The Sierra-1 V2 doesn't shy away and attempts to play them at full amplitude resulting in fair amount of distortion. Fortunately this only shows up in my "speaker killer" tracks. On all others, even deep bass was reproduced exceptionally well.

Conclusions
When I was offered this speaker for review at first I thought, well it was measured and tested elsewhere so maybe I need to pass. I am glad I did not and performed the review. We got to test a random production sample and managed to extract some other insights about the speaker. In a nutshell, the design is heavily optimized for off-axis and predicted in-room response which makes the speaker very room friendly and is critical in listener preference studies. The on-axis response which while excellent in this product class, shows a bit of variations. My informal testing shows that slight corrections to response yields subjective improvements in listening. Whether this translates to others or not, I can't say.

The high level picture is that company has made an incredible investment in instrumentation and optimization of its product and it shows. Likely ton of effort has gone into scan after scan to produce some of the best measurements I have seen. Having a Klippel NFS is one thing. Putting up with multi-hour scans for every test iteration is another.

It is my pleasure to add the Ascend Acoustics Sierra-1 V2 speaker to my recommended list.

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

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@amirm Nice review again! Thank you.

I started with Band 2, filling that small bass dip.

Don’t you mean, filling that small dip around 3 kHz?