YG Acoustics Sonja 1.3 loudspeaker Measurements

Sidebar 3: Measurements

Because of the YGA Sonja 1.3's bulk and mass, I performed the farfield measurements, using DRA Labs' MLSSA system and a calibrated DPA 4006 microphone, only on the Sonja 1.1 module. For the nearfield and spatially averaged room responses of all three modules, I used an Earthworks QTC-40 microphone. The Sonja's voltage sensitivity is specified as 88dB/2.83V/m. However, my estimate was significantly less than that, at 85dB(B)/2.83V/m. The Sonja 1.3 needs a big amplifier to reach the appropriately high SPLs of which it is capable.

The 1.3's electrical impedance is specified as 4 ohms, with a minimum value of 3 ohms. Fig.1 show the measured impedance. It ranges between 3 and 6 ohms most of the time, with slightly greater values in the bass and in the upper midrange. However, not only does the magnitude remain between 3 and 4 ohms throughout the midrange, with a minimum magnitude of 2.73 ohms at 281Hz, but the electrical phase angle is significantly inductive in the midrange, with a combination of 3.8 ohms and +45° phase angle at 814Hz. This speaker needs to be used with an amplifier capable of delivering both amps and volts in quantity—I suspect that the hardness I noted at sustained SPLs above 100dB was simply due to the amplifiers clipping into the demanding impedance. Fig.2 shows the impedance and electrical phase of the Sonja 1.1 module alone. As the input signal is high-pass filtered with a series array of capacitors, this results in the Sonja 1.1 becoming a highly capacitive load in the upper bass and below. Yes, the speaker's output is rolling off by the time you reach the combination of 4.2 ohms and –60° at 70Hz, but music has a lot of energy in this region. The Sonja 1.1 is thus an even more difficult load than the Sonja 1.3, and needs to be used with an amplifier capable of delivering large currents without flinching.1

713YGS13fig01.jpg

Fig.1 YGA Sonja 1.3, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

713YGS13fig02.jpg

Fig.2 YGA Sonja 1.1, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

The traces in figs. 1 and 2 are free from the small discontinuities that would indicate the presence of enclosure resonances; investigating the vibrational behavior of the Sonja 1.1's cabinet with a plastic-tape accelerometer, I found nothing untoward, other than a very mild mode at 815Hz (not shown). However, the 1.2 and 1.3 cabinets emitted faint, metallic-sounding bonks when tapped, and with pink noise I could hear faint whistles from the woofer enclosures when I listened with a stethoscope. The accelerometer revealed the 1.2 cabinet to have relatively strong resonances at 580 and 795Hz, the 1.3 cabinet at 560 and 795Hz (fig.3). Although these frequencies are well above the passbands of the 1.2 and 1.3 woofer enclosures—you would not, therefore, expect them to be excited with music playing—I could faintly hear the midrange resonances when I used a stethoscope to listen to the woofer enclosures while the speaker played pink noise. This is presumably due to the very tight mechanical coupling between the three enclosures. YGA's Yoav Geva does say that these panel vibrations above the woofer crossover frequency are due to the speakers being sited on a nonrigid floor, which hinders efficient draining of the vibrations to ground.

713YGS13fig03.jpg

Fig.3 YGA Sonja 1.3, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of 1.3 woofer unit side panel (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

Turning to the YGA's frequency response, the Sonja 1.1's acoustic crossover in the farfield is shown in fig.4. The two midrange units (red trace) offer a superbly flat output in their passband, handing over to the tweeter (blue trace) just below 2kHz. The tweeter's output is basically flat, but with some small peaks and dips evident. (A response graph supplied me by YGA, taken in the NRC's anechoic chamber in Ottawa, was identical in this respect.) The acoustic filter slopes appear to be close to fourth-order low-pass for the midrange drivers, third-order high-pass for the tweeter. The midrange units roll out below 100Hz, reaching –6dB at 65Hz, as specified.

713YGS13fig04.jpg

Fig.4 YGA Sonja 1.1, acoustic crossover on HF axis at 50", corrected for microphone response, with summed nearfield responses of midrange units (red) plotted below 400Hz.

Fig.5 shows how the Sonja 1.1's individual responses sum in the farfield, averaged across a 30° horizontal window centered on the tweeter axis (blue trace), to which is added the combined response of the Sonja 1.2 and 1.3 modules (red trace). Despite their different enclosure shapes, the 1.2 and 1.3 behaved identically; the summed nearfield outputs of the 1.2 and 1.3 roll off below 30Hz and above 50Hz. With the spatial averaging evening out the tweeter's behavior in its passband, the Sonja 1.1 offers an astonishingly flat farfield response.

713YGS13fig05.jpg

Fig.5 YGA Sonja 1.3, anechoic response on HF axis at 50", averaged across 30° horizontal window and corrected for microphone response (blue), with nearfield responses of Sonja 1.1 module (blue) and the sum of the 1.2 and 1.3 modules (red) plotted below 400 and 200Hz, respectively.

Whether or not a flat on-axis response corresponds to a neutral balance in-room depends on the speaker's radiation pattern. The Sonja 1.1's lateral dispersion, normalized to the tweeter-axis response, is shown in fig.6. Other than in the top octave, the YGA's output generally drops smoothly and evenly to its sides, but there is a slight off-axis flare evident at 5.5kHz. However, this is mainly due to a small suckout in the on-axis response filling in to the sides. In the vertical plane (fig.7, plotted across the full ±45° window rather than the ±15° I sometimes use for large, cumbersome speakers), the vertical dispersion is disturbed by a lack of energy developing more than 10° above and below the tweeter axis. This will be due to destructive interference between the spaced midrange units, and confirms my listening impression that the Sonja's tweeter needs to be aimed at the listening position.

713YGS13fig06.jpg

Fig.6 YGA Sonja 1.1, lateral response family at 50", normalized to response on HF axis, from back to front: differences in response 90–5° off axis, reference response, differences in response 5–90° off axis.

713YGS13fig07.jpg

Fig.7 YGA Sonja 1.1, vertical response family at 50", normalized to response on HF axis, from back to front: differences in response 45–5° above axis, reference response, differences in response 5–45° below axis.

The red trace in fig.8 shows the Sonja 1.3s' spatially averaged response in my listening room, with the response of the Vandersteen Treos I reviewed in March shown in blue. (Both traces were generated by averaging 20 1/6-octave–smoothed spectra, taken for the left and right speakers individually using SMUGSoftware's FuzzMeasure 3.0 program and a 96kHz sample rate, in a vertical rectangular grid 36" wide by 18" high and centered on the positions of my ears. This eliminates the room acoustic's effects, and integrates the direct sound of the speakers with the in-room energy to give a curve that I have found correlates reasonably well with a speaker's perceived tonal balance.) Both speakers benefit from the 32Hz diagonal mode in my room, but whereas the Treos rolled off below that mode, the Sonja 1.3s extended at full level to well below 20Hz. There is still a lack of energy between 70 and 120Hz, which leaves the YGAs' lows sounding slightly disconnected from their midrange, but the upper-frequency regions are generally even. Compared with the Vandersteens, which are no slouches in the treble, the YGAs have a slight excess of energy in-room between 5 and 15kHz, which may well correlate with the somewhat analytic-sounding balance.

713YGS13fig08.jpg

Fig.8 YGA Sonja 1.3, spatially averaged, 1/6-octave response in JA's listening room (red); and of Vandersteen Treo (blue).

Turning to the time domain, the Sonja 1.1's step response on the tweeter axis (fig.9) indicates that the tweeter and midrange units are all connected in positive acoustic polarity. The decay of the tweeter's step smoothly blends with the start of the midrange step, correlating with the excellent frequency-domain integration of their outputs seen in fig.4. The two woofers' step responses (not shown) confirm that these, too, are connected in positive acoustic polarity. The Sonja 1.1's cumulative spectral-decay plot on the tweeter axis (fig.10) is superbly clean.

713YGS13fig09.jpg

Fig.9 YGA Sonja 1.1, step response on HF axis at 50" (5ms time window, 30kHz bandwidth).

713YGS13fig10.jpg

Fig.10 YGA Sonja 1.1, cumulative spectral-decay plot on MF axis at 50" (0.15ms risetime).

Finally, I very rarely examine a speaker's distortion because of the difficulty of doing so with absolute accuracy outside of an anechoic chamber. (Ambient noise and the room's acoustics are both interfering variables.) Out of curiosity, however, I did look at the Sonja 1.1's linearity. This is a low-distortion speaker. A 500Hz tone at a high continuous SPL of 95dB at 24" generated just 0.1% of third harmonic (fig.11), while the distortion harmonics were even lower than that with a 1kHz tone at the same SPL (fig.12). In this graph, the second and fourth harmonics are the highest in level, at –66dB each (0.05%). With a stimulus higher in frequency, the tweeter produced about 0.2% of second harmonic at this same high SPL.

713YGS13fig11.jpg

Fig.11 YGA Sonja 1.1, spectrum of output on HF axis at 24", 500Hz at 95dB SPL (10dB/vertical div., linear frequency scale).

713YGS13fig12.jpg

Fig.12 YGA Sonja 1.1, spectrum of output on HF axis at 24", 1kHz at 95dB SPL (10dB/vertical div., linear frequency scale).

The YGA Sonja 1.3 offered the excellent measured performance you should expect at its price.— John Atkinson



Footnote 1: The 1.1 is also available without the high-pass filter.
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COMMENTS
carlosgallardo's picture

I'd like to read a comparison between the Sonja and the Magicos Q5 and Q7, or Willson Alexandria

 

Bulsara's picture

It's a bargain ... stupid !

Lofty's picture

John,
after the YGA guys left  - why didn't you install your usual cabling? It surprises me you didn't revert to your constant , then install the K-S cables and report the difference?

As you might say, "color me puzzled?"

John Atkinson's picture

To respond to these points, with speakers as large as the YG Sonja 1.3, Wilson Alexandria XLF, and Magico Q7 or Q5, the logistical problems doing side-by-side comparisons are immense. For example, I have a basement listening room and I don't see how I could get either the Wilsons or either of the Magicos in that room? If I remember correctly, each Magico Q7 weighs 700 lbs. (The YGs each split into three modules, which made the task manageable - just.)

But you can find our reviews of the XLF and Q5 at http://www.stereophile.com/content/wilson-audio-specialties-alexandria-xlf-loudspeaker and http://www.stereophile.com/floorloudspeakers/magico_q5_loudspeaker/index.html .

Regarding the lack of cable comparisons in my Sonja review, I ran out of time. However, I still have the Kubala-Sosna cables and will publish some comparisons, using different speaker, later in the year.

Regarding the sarcastic comment that the YG speaker is a "bargain," I feel that while the Sonja 1.3 is very expensive, it is indeed fairly priced given the bill of materials,  the cost of skilled labor, and the use of capital-intensive equipment (the cost of which has to be amortized over a relatively limited production run), to make it. Remember also that with a speaker this bulky and heavy, even the cost of shipping a pair to the dealer is expensive and that cost has to be built into the retail price.

I am reminded of a story told me by YG's Yoav Geva. He was contacted by a would-be customer who complained about a YG speaker's price and who estimated that there was around $200 worth of raw aluminum stock in that speaker.

"Send me a check for $200 and I'll send you the raw aluminum so you can build your own speaker!" responded Mr. Geva :-)

John Atkinson

Editor, Stereophile

GeorgeHolland's picture

Bulsara, yes it is stupid to say it's a bargain.

Lofty, Mr Atkinson doesn't test cables just allows subjective reviews.

Mr Atkinson, "I feel that while the Sonja 1.3 is very expensive, it is indeed fairly priced given the bill of materials,  the cost of skilled labor, and the use of capital-intensive equipment (the cost of which has to be amortized over a relatively limited production run), to make it"................"Having seen YGA's capital-intensive operation, I am surprised not only that the Sonja 1.3 doesn't cost more than it does, but also that it costs slightly less than the company's earlier flagship model."

Well I'll keep that in mind next time I have a complete house built from scratch. I think I'd get much more for the money than just a pair of speakers. Good luck to them selling enough of these to recoup their investment plus make a profit. Not many very wealthy people are going to buy these.

For $108,000  you can buy all the electronic, audio, computer, wood working equipment to build your own speakers and have plenty left over for a good sized down payment on that house. Plus you have the satisfaction of learning how to make those speakers and can make more and more for your family and friends. People do this all the time. Check out the DIY audio and speaker forums. Plenty of already tried and true speaker plans on there.

John Atkinson's picture

GeorgeHolland wrote:
For $108,000  you can buy all the electronic, audio, computer, wood working equipment to build your own speakers and have plenty left over for a good sized down payment on that house.

Not if you want to emulate the YG speakers. The 5-axis CNC machines used to mill all the speaker parts cost, if I remember correctly, several hundred thousand dollars each. And then there is the positive air pressure machine room, the swarf and scrap collection machines, the salaries of the skilled operators, and the cost of the milling tools, themselves. Let alone rent, cost of capital, worker health insurance and benefits, etc. And while aluminum is relatively easy to machine, the mineral-loaded phenolic resin material used by Wilson wears out several tools, at a couple of hundred dollars a time, for each enclosure.

It is all too easy for an armchair critic to poke scorn at companies like YG and Wilson. But the enterpreneurs behind these companies have done something the armchair critic has never done, which is to put at risk their ability to feed their families in order to realize their dreams.

No-one forces you to buy speakers like thiese, Mr. Holland, but you have to respect what their manufacturers are trying to achieve.

John Atkinson

Editor, Stereophile

GeorgeHolland's picture

Who wants to emulate the YG? There are plenty of designs out there just as good or better.  Look at Mr Linkowitz  http://www.linkwitzlab.com/   or John K's http://www.musicanddesign.com/naomain.html  others are also out there.

You don't have to spend obscene amounts like on a YG or Wilson to have fantastic sound.

Those impedance and phase numbers for the YG aren't exactly astounding by any means, you would think for the money that they would have tidied up the problems there and also the panel vibrations are not worthy of the price paid.

"But the enterpreneurs behind these companies have done something the armchair critic has never done, which is to put at risk their ability to feed their families in order to realize their dreams"

Oh stop it I might cry. Poor little Wilson has it rough I can tell.

"No-one forces you to buy speakers like thiese, Mr. Holland, but you have to respect what their manufacturers are trying to achieve."

Their achievement is to charge as much as possible and hope the rich buy it.

ChrisS's picture

Your links don't work.

JohnnyR's picture

  Too lazy to copy and paste the links themselves into their browser

 

http://www.linkwitzlab.com

http://www.musicanddesign.com/naomain.html

[Edit by John Atkinson]

[Additional edit by John Atkinson]

Regadude's picture

The speakers in those links don't look impressive. But, I will reserve judgement because I HAVE NEVER HEARD THEM. 

A person would be silly to denigrate a product they have never seen and heard in person...

GeorgeHolland's picture

Oh that's right you can't.wink

Both of those speakers are very well known and admired in the audio community of course they aren't silly expenisve so they don't have the snob appeal like Wilson or YG does,

JohnnyR's picture

will be able to pick out what is and what isn't good about a product soley based upon the measurements, layout and other appearances. [flame deleted by John Atkinson]

corrective_unconscious's picture

Hope those manufacturers are better with audio design than they are with graphic design or even information graphics, because those are some primitive repositories. Irksome.

(Just for the record I'm quite sure it's possible to obtain superlative speakers for under 10k or 15k...even semi mass produced ones via brick and mortar audio shops.)

GeorgeHolland's picture

getting across the information. They are more of an info site than trying to sell something. If you want glitz then look elsewhere.

xsipower's picture

First just let me say WOW!! Nice speakers (no I am not being sarcastic). I would love to have a pair of these in my living room.

I will have to agree with Mr. Atkinson on his assessment of why these speakers cost what they do. Given that these speakers are not really considered “mass produced”, but made in small quantity I can understand the cost. Machining is very expensive and not a cheap way of making metal parts. It is a slow process and requires expensive machines that must be maintained and staffed by well-paid labor. The benefit of machining is its flexibility and precision. As they say – time is money.

 If they were truly made in high quantity, most manufactures would shift to casting or other forming methods which can save a lot of money because it is fast and does not require as expensive machines. That kind of work is usually farmed out to “third world” or “developing countries”.  Of course some finish machining would be required, but nowhere near as much as with billet machining.

I know that there is a lot of animosity toward the high end audio industry for their prices. Some of it I would say has foundation, but not all of it. People need to understand that many of these companies are small businesses that sell only in the hundreds, some if that. We get used to the mass produced “Made with slave labor” prices from Best Buy and the like. The business model for the smaller companies is totally different. They need to have on staff not only the founders and lower waged assembly people, but engineers and technicians who are expensive. Plus pay for insurance, rent, taxes, utilities, etc. Then there are the materials and subcontractors and expensive capital equipment. They must also spend their own money on trade shows and advertisements. They are not a non-profit organization.

I am an engineer myself; and have spent some 25 years in research and development. Developing products is expensive. While developing a product, you are making no money on it. It eats away at your cash like no tomorrow. By the time let say a high end amplifier goes from concept to production, a year can be spent.  It first needs to be designed on paper and simulated on computers. Then it must be bread boarded, then prototyped – maybe two or three iterations. Then it must be designed for manufacturing. That can add up to hundreds of thousands of dollars if not more. That investment must be recouped with hopefully some profit. Some can make stuff in a garage and be cheap and good, but once you move out from a garage your expenses balloon.

Yes we can look at it from an armchair DIY point of view, but that is way too simplistic and disrespects the effort it takes to make a well-designed product that can be reliably reproduced in quantity. We need to be careful when making judgments on high end items.

ChrisS's picture

Georgie,

Are you amongst the many un-wealthy who are also not going to buy these speakers?

carlosgallardo's picture

Thank you for making it clear for all of us.

I understand your logistical problems, my intention was not to complain but having more information from a reviewer like you that got the opportunity to listen to all of them, and at the same time have an respectable oppinion.

MVBC's picture

"YGA's Sonja 1.3 is that rare beast: a true full-range loudspeaker capable of playing at realistic sound-pressure levels"

And

"Sensitivity: 88dB/2.83V/m"

Good one!laugh

GeorgeHolland's picture

Mr Atkinson's words: "The Sonja's voltage sensitivity is specified as 88dB/2.83V/m. However, my estimate was significantly less than that, at 85dB(B)/2.83V/m"

So takes even twice more the power for the same loudness. If 1 watt = 85 dB then 32 watts = 100 dB and above 100dB it made the amp clip? Yep really worth every penny.

"This speaker needs to be used with an amplifier capable of delivering both amps and volts in quantity—I suspect that the hardness I noted at sustained SPLs above 100dB was simply due to the amplifiers clipping into the demanding impedance."

So lets say you spend another $50,000 on an amp capable of driving these. Nice.

ChrisS's picture

If Georgie can't find it at Wal Mart, Georgie ain't buyin'....

MVBC's picture

Nope, that is not his point: it means it'll take me 130 watts to get to 120dB on my JBL pro drivers system while you'll need 2,000 watts with these $100k fancy speakers driving mickey mouse drivers with very expensive diaphragms... To call these being able to reproduce realistic levels is a farce.

harishcs's picture

Even assuming that YG is not being unreasonable about the selling price, the question is whether all that elaborate machining,etc is necessary for achieving state of the art sound ?  

 

 

 

 

JohnnyR's picture

The answer is NO

[Off-topic text deleted by John Atkinson] Magico uses aluminum structures in their $20,000 speakers but is it worth the cost?  You can throw endless amounts of money into making things appear "better" and look impressive but I'd rather have a set of speakers that come with an actual frequency response graph included and it's not that hard to do so yet who does? It would prove that quality control is constant with not just the sample loaned to Atkinson but also the pair you yourself bought.

ChrisS's picture

Having truth and fact defined for you by Uncle Joseph for so many years, Comrade JRusskie, no wonder you trust a piece of paper with a graph over your own hearing.

JohnnyR's picture

Yet you seemed to have overlooked that fact. Atkinson takes frequency graphs, do you trust him? Floyd Toole trusts graphs, that's how the speaker industry found out what consumers liked the best. A speaker that has flat frequency rersponse. Too bad some designers overlook the importance of a benign impedance that doesn't tax the abilities of the amp.Do you trust anything other than your willingness to open mouth and insert foot?

ChrisS's picture

And they all trust their hearing too!

John Atkinson's picture

JohnnyR wrote:
I'd rather have a set of speakers that come with an actual frequency response graph included and it's not that hard to do so yet who does?It would prove that quality control is constant with not just the sample loaned to Atkinson but also the pair you yourself bought.

For production QA on finished speakers, YG uses MLSSA with the speaker suspended high in the air to give an anechoic time window of 13ms. But as I said in the review but you seem to have overlooked, YG did send me the response of what I understood to be the finalized protoype sample of the Sonja 1.3, measured in the NRC's anechoic chamber in Ottawa. And as I also wrote in the review, my measurement of the farfield response of my sample of the Sonja was almost identical in the midrange and above to YG's NRC measurement of the prototype. YG therefore does have very effective quality control and your insinuation is incorrect.

John Atkinson

Editor, Stereophile

JohnnyR's picture

Isn't the same as the production run in many cases plus you got a cherry picked set of speakers or do you believe that it was just a randon set the shipping clerk chose to send you? You seemed to have overlooked that I said  "but also the pair you yourself bought." so my point is still valid. Will YG send out frequency specs for every speaker?

John Atkinson's picture

JohnnyR wrote:
Isn't the same as the production run in many cases...

Again you misunderstand what you read. The sample measured in the NRC chamber was the final protoype, ie, the reference sample of the design. All Sonja 1.3s are measured as the final step of the production process and their response compared to that of the reference measured under identical conditions. The close tolerance of that QA process is confirmed by the fact that my measured response of a production sample was essentially the same as that of the reference sample, even given the fact the former was measured with a swept sinewave in the NRC chamber and I used a quasi-anechoic MLS technique.

I am sure there are companies that have poor or inconsistent QA. YG Acoustics is not one of them. It's time for you to stop beating this dead horse.

John Atkinson

Editor, Stereophile

GeorgeHolland's picture

So in other words, they don't supply a print out of the frequency response of the actual speakers you buy.

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