Sigberg Audio SBS.1 Active Speakers
Analog: RCA, XLR balanced (in/through)
Digital: Optical, Coaxial/SPDIF (in/through), AES (in/through)
Sigberg Audio is a newer company that launched in early 2020 and specializes in high-end loudspeakers with a markedly different design philosophy. Their loudspeaker systems are geared toward the two-channel crowd yet promote a design that necessitates subwoofers. Historically, two-channel purists shunned subwoofers as if they were the bubonic plague. Sigberg Audio’s sole loudspeaker (as of this writing), the SBS.1, doesn’t even attempt deep bass and leaves that range entirely to subs. There is certainly merit to this idea in that it allows the loudspeaker to focus on the frequency range that doesn’t require a large enclosure or massive excursion ability. In other words, it frees up the loudspeaker to go for a wide dynamic range without the need for a large enclosure that lower bass output would demand.
Sigberg Audio also deviates from traditional hi-fi loudspeakers by making their speakers self-powered, so no amplifier is needed. Not only is it self-powered, but it also has digital inputs, so the user doesn’t even really need a preamplifier or DAC; all they need is something with a volume control. If the source player has volume control, such as a PC, they can hook the speakers up directly to the source. Furthermore, no outboard equalization is needed since the SBS.1s have a built-in 9-band parametric equalizer. Audiophiles traditionally like to have their electronics to be as segregated as possible, but Sigberg has taken the opposite tack and has consolidated much of the electronics onboard the speakers. The SBS.1s can be used like typical powered speakers as well and are likely to do so, but the choice is there to skip some of the outboard electronics if desired for a minimal setup.
For review today, we have the Sigberg Audio’s SBS.1 speakers. They are an upscale bookshelf loudspeaker and priced as such at over $6.5k/pair (pricing in pinned on the Norwegian Krone so other currencies will fluctuate, but the pricing should hover around $6.5k to $7k/pair USD). But for this cost, shipping is included as well as all taxes and import fees.
Update 12/12/22: The latest pricing is $5,170/pair which is a nice discount.
The questions we will ask in this review for such an unusual speaker are: what do these medium-sized bookshelf speakers do to justify that kind of price? What situation are they best suited for? And how well do Sigberg’s unusual design theories pan out in practical use? Let’s now dig in to find out…
The SBS.1 arrived in a double-layered cardboard box and tucked in some stiff foam stand-off pieces. The packing should be adequate for normal shipping practices, but I do think that something of this price point might benefit from thicker foam pieces just in case of an abnormally rough shipping transit.
Once out of the box, the SBS.1 speakers present themselves as sleek black units with a fine satin black finish. The edges and corners have a slight rounding and the cabinet shape has a slight backward lean that combines to give them a streamlined look that is a definite improvement over the standard oblong box that most speakers use. The driver cones have a glossy sheen that stands out as the aesthetic focus of the SBS.1 from an industrial design standpoint. There is a small Sigberg logo at the bottom front of the speaker to help save it from being too minimalist. The included grilles hide the entire front of the speaker and do make them look a bit drab, but some people loathe the appearance of drivers, so manufacturers must supply grilles. Overall, these speakers look quite nice without being flashy, and I would call them elegantly restrained. They would not be out of place in a luxurious decor, and their simple, sleek styling would enable them to fit in almost any type of interior design.
As mentioned before, the SBS.1 speakers are active bookshelf speakers that are intended to be used with a subwoofer. They are a 2.5-way sealed design that uses a coaxial driver. Let’s get into the details by starting with the drivers. The tweeter is a 1” silk dome embedded in midwoofer ,which is used as a waveguide. There are two midwoofers; one of which is used in the coaxial driver and one standalone midwoofer mounted below it. Coaxial designs have the advantage of having the tweeter always be in phase with the midrange driver. One of the advantages of coaxial designs is that the acoustic center of the woofer and tweeter remains the same irrespective of where you are in relation to the speaker – above, below, left, right, or center of the driver. That means the drivers are not only time-aligned on-axis, they are time-aligned at any off-axis angle as well. With a typical speaker where the tweeter is above the woofer, that is not true. When the speaker is time-aligned on tweeter axis, standing above or below the speaker will place you closer to the tweeter or woofer respectively, so the woofer and tweeter are no longer time-aligned as the sound from the tweeter will arrive first. This affects the phase matching between the drivers and causes peaks and dips in the response.
Since the upper midwoofer shares the same bass range as the lower woofer, the SBS.1 should be much more of an acoustic “point source” speaker than typical. Most loudspeakers try to emulate a point source location from the tweeter’s position. This is often done with mixed success. The success of this approach is key toward getting all of the drivers to add up to a coherent, unified sound. The SBS.1 takes this very seriously, with the coaxial driver blending in with the midwoofer with no timing difference caused by distance difference, since there is no distance difference. The midwoofer’s shared frequency ranges also assists here because there is no crossover transition where they could cause conflicts at any angle. The 600hz low-pass filter on the lower woofer will enable both woofers to act as a single point of acoustic emission since the center-to-center spacing of the drivers, which is about 6.5 inches, is much less than the upper-end wavelength of the low-pass filter which is 22.6 inches.
As was mentioned before, the midwoofers do not attempt deep bass at all, and the low end of the response window for the SBS.1 is 90Hz (+/-2dB). This brings advantages and disadvantages. The obvious disadvantage is the speaker needs a subwoofer in order not to sound thin due to lack of deep bass. That is a reasonable compromise because if you can afford these speakers you can certainly afford a subwoofer or two. There are two big advantages of this design choice both of which are directly related to that unyielding maxim of loudspeaker design, “Hoffman’s Iron Law,” which essentially states that you can have two of the following three attributes but never all three: smaller size, deeper bass, or wider dynamic range. Most speakers trade each of those attributes to varying degrees, but the SBS.1 goes in hard for small size and dynamic range at the expense of deep bass. This means that these speakers should be able to get very loud, and of course, that they are very reasonably sized. Their specs suggest that they should get extremely loud for their size, but we will see for ourselves in the ‘listening sessions’ segment.
The midwoofers use coated paper cones which can be a good material to reach higher frequencies without severe breakup modes. The cones are attached to the driver frame with a double-roll surround. Double-roll surrounds can often be used to trade excursion for sensitivity, and that makes sense in this design which is going for dynamic range over low-frequency extension. The midwoofers use some beefy 4” diameter and ¾” thick ferrite magnets. That is fairly heavy-duty for 5.5” midwoofers, and it feels weighty (although what really counts is the actual magnetic field strength in the voice coil gap rather than the magnet size). The midwoofers also use a copper shorting ring to reduce distortion products. The woofers are rated for 120-watt power handling (by the AES 2-1984 standard) and so make a good match for the onboard amplifiers.
Sigberg uses a sealed cabinet which is another sensible design choice for a loudspeaker that is intended to be used with a subwoofer. Loudspeakers with ports can often have rapidly shifting phase responses around the port-tuning frequency range, and that can make it difficult to get in acoustic phase with the subwoofer. Sealed speakers tend to have a predictable phase response that is much easier to integrate with subs. The cabinet has a 4-degree tilt, and this is for more than just looks; Sigberg says this was done to provide slightly more high-frequency energy into the room since the on-axis angle is tilted slightly away from the listener. The paneling is made from ⅝” thick MDF. Each driver has its own sealed compartment, and the amplifier is in a sealed compartment as well, so the internal bracing network is very substantial with solid panels sectioning the SBS.1 internally. Given that it is already a smallish speaker, that ought to make the enclosure extremely rigid and inert. The driver compartments are lined on all sides with a composite felt material that is a much better damping substance that the usual polyfill. The premium build quality adds up to a hefty little speaker here at 21 lbs. each.
As powered speakers, the SBS.1s use some of the highest performing electronics available. Each speaker uses three Hypex nCore amplifiers. These are state-of-the-art class-D amps, which are some of the lowest distortion and lowest noise amps around. In fact, these are the lowest noise active speakers I have encountered to date. They are dead quiet unless you place your ear right up against the tweeter where there is a very faint hiss. Each midwoofer gets 125 watts RMS and the tweeter gets 100 watts RMS for a system total of an astounding 350 watts RMS per speaker. That is a lot of power for such a small loudspeaker, and it should have a tremendous amount of dynamic range for its size, especially considering that the drivers are rated to handle that much power. The SBS.1 uses an active crossover, of course, and the crossover slopes are not traditional ones. The tweeter/midwoofer crossover frequency is 2.5kHz and the high and low pass filters start with a gradual 1st order slope but become a sharper 2nd order slope as the filter progresses. Being a 2.5-way speaker, the coaxial midwoofer shares the bass range with the lower woofer, but the lower woofer gets high-passed at 600Hz. Sigberg tells me that this unusual mixed order filter structure was done to improve the phase response.
The SBS.1 has a variety of connectivity to accommodate most system types. On the analog input side, there is a balanced XLR input and through, as well as unbalanced RCA left and right inputs. On the digital side, there is an AES input and through, a S/PDIF input and output, as well as a TOSLINK input. For the digital inputs, there is a selector that lets you designate the speaker to playback the left, right, or both channels, although the speaker pair come preconfigured for left and right channels, so it shouldn’t be necessary to make that selection unless you want to double-check it. Many digital sources only offer a single S/PDIF or TOSLINK output, and in those cases, the user will need to get a splitter to divide the signal into two streams. Digital audio signal splitters can be inexpensive, but they are small and widely available, so that shouldn’t present a problem.
The SBS.1 amplifier has three preset response curves to choose from: Preset 1 provides a flat response, Preset 2 gives the treble a slight elevation to compensate for grille use, and Preset 3 shelves the treble by a few dB for those who prefer a warmer sound. Users also have the option of tailoring the response to their own taste because the SBS.1 comes with a 9-band parametric equalizer when they download the DSP software provided by Sigberg’s website. Users will need to hook up the SBS.1 to a PC with Windows 7 or higher using the provided USB cable to access the equalizer, but the equalizer was easy to use. I would recommend most users to just stick with the provided presets for the best sound unless they really know what they were doing with an equalizer. The Hypex software package also allows the user to adjust other parameters such as gain settings, standby settings, LED brightness, and a few other options.
The SBS.1 speakers have an active limiter so they can be played loud without worrying about overdriving the woofers. In my own listening, the amp was somewhat warm to the touch at idle but never became hot even after higher-level listening. Sigberg tells me that there are built-in thermal sensors that will lower the maximum output by 6dB if they detect excessive heat, but that has never happened in any of their testing. That is not surprising considering the enormous efficiency of class-D amplifiers where much less energy is lost as heat compared to class-A/B designs.
In my 24’ by 13’ (approximately) listening room, I set up the speakers with a few feet of stand-off distances between the back wall and sidewall and equal distance between speakers and my listening position. I experimented with toe-in angles and ended up preferring the user manual’s recommended angle of the speakers facing straight ahead in a parallel direction. The listening distance from the speakers was about 8 feet. The subwoofer in use was the Sigberg Audio 10D.
For an example of the SBS.1’s performance with orchestral content, I choose “Symphony No.5” by Christopher Rouse. This wildly dynamic recording that I found in 24bit/96kHz hi-res on Qobuz is released by the Naxos label and was performed by the Nashville Symphony under the direction of Giancarlo Guerrero. Rouse was a celebrated American composer whose style fell under the designation ‘neo-romanticism’ and has a distinctly American signature. Symphony No.5 is an energetic and emotional piece that runs through a variety of moods and gives every instrument a chance to shine. In fact, this 2020 release won the Grammy for “Best Classical Contemporary Composition,” although sadly that occurred only a year after Rouse’s passing. This world premiere recording was given the excellent recording quality that the Naxos label is known for.
The precision of the soundstage of the SBS.1 speakers was the first thing I noticed. It was easy to tell through these speakers that the recording was done with the microphone over the performing group. That doesn’t break the concert hall illusion, although it doesn’t have the acoustic ambiance of a distant listening position. Orchestral sections were easily defined in the soundstage with much of the brass on the right side and much of the woodwinds on the left. The different strings were localizable as well, with violins and violas more toward the left and cellos and bass to the right. The effect was one of listening at the center of a close row in seating. All the instruments sounded natural in timbre, and there was no spectral tilt that I could discern. Dynamic range was quite surprising considering the size of the speakers, although this wasn’t a shock to me since I already knew the capability of the internal components. Someone who wasn’t already familiar with the design of the speaker would surely find their ability to tackle the peaks of the crescendos to be quite astounding. The depth and the breadth of the presentation by the loudspeakers left me nothing to complain about. With the inclusion of the subwoofer, it all sounded very much like what would be expected of a large full-range tower speaker.
For something with an emphasis on a sole vocalist, I found a striking new release titled “Lysbærer” by Nanna Barslev, again on Qobuz. Barslev hails from Denmark and stays close to her roots by creating Nordic folk music, although this is far too eclectic to categorize as just ‘folk’ music. There is an atmospheric and cinematic quality to it, but it would be too emotionally charged to be labeled ‘new age’ music. Think Enya but with war paint. This terrifically produced, hi-res recording is Barslev’s first album, and I have no doubt it will propel her to greater heights. Hopefully, any forthcoming music by her will maintain the artistry that she exhibits here in “Lysbærer.”
The album opens with an ethereal choral effect that sweeps across the soundstage, and the width of the soundstage seemingly exceeded the span of the speakers’ placement. When the song’s verse hits, Nanna’s voice holds an anchored position squarely in the center of the soundstage. The imaging was extremely well-defined. Nanna was flanked by a harp and hurdy-gurdy playing (for those who don’t know, the hurdy-gurdy is a medieval string instrument that always sounds sorrowful- you have likely heard it in many movies set in the middle ages). The percussion including the bass drum was sharply expressed, and the transient behavior left nothing to be desired. Nanna’s voice was gorgeously rendered and sounded full and natural. Studio effects sometimes lent her a dreamlike quality such as in the intro for track 7, “Jagtmarker,” a gradually-building passage that the SBS.1 speakers gave a monumental sensation contrary to their moderate size. That story is true for much of this album; the SBS.1 speakers were able to sound much bigger than they look. Of course, that size disparity between looks and sound is due in large part to the subwoofer, but the soundstage and dynamics were the speakers’ doing. “Lysbærer” sounded great on the SBS.1 speakers; other speakers might offer a different presentation of this album, but not necessarily a better one.
For an audio experience like no other, I listened to “Doctor Belief” by Creme Rinse. Creme Rinse is a Japanese artist who threads all kinds of audio samples taken from a variety of media and strings them over original music and sonic atmospheres to form a science fiction narrative that stretches over the length of the album. As an audio collage used to create a cyberpunk setting, there is a wide assortment of sounds used to keep things interesting. There is an eclectic mix of music as well, although much of it is electro in keeping with the futuristic theme of the album. Throughout the album, a story is ‘suggested’ that a criminal mastermind named Doctor Belief escapes a space prison and inhabits people’s minds to compel them toward actions that create chaos throughout the solar system. For those who are curious, the album can be had at the recording label Seikomart’s Bandcamp page. This bizarre pastiche of sound effects and music certainly wouldn’t be to everyone’s tastes, but it has an imaginative sound mix that would show off the abilities of a high-end sound system.
Sound effects and spoken word samples were given a crisp reproduction by the SBS.1 speakers and were still perfectly clear even amongst Creme Rinse’s at-times busy sonic mixture. The soundstage, bizarre as it is in an album like this, came through with a dizzying effect. The soundstage would rapidly shift like a quickly edited movie and would require the listener to reorient themselves for every ‘cut,’ but the SBS.1 speakers were able to make it clear where these transitions were. The music could pound through the speakers when asked for, but they could also delicately reproduce the more relaxed and ambient medleys when they came along. Indeed, they could give my room an utterly club-like sensation at some moments, notwithstanding the sub’s contributions. Again, the system sounded much larger than it actually was. This sound mix is quite heavy in the use of bass, and, of course, the subwoofer carries some of that weight, but most bass in both music and movie bass is largely mid and upper bass, so the main speakers must be capable in that range as well. I am happy to report that the SBS.1 was easily able to keep up with the Sigberg Audio 10D subwoofer in delivering a strong, punchy bass. My guess is that this music was created using headphones primarily and that it will primarily be consumed by headphone users, but it sure is a kick to hear with such a high-fidelity sound system that Sigberg Audio has provided.
To see what the SBS.1 loudspeakers could do at a loud level, I threw on Malux’s “Motive” on the Vision Recording label. This six-track EP is just one drum’n’bass banger after another. This is loud and aggressive electronic music and was intended to be listened at higher levels. Incessant percussion, growling lead synths, and bombastic bass are the stuff that this music is made of. “Motive” is more than just repetitive dance music, however. There is inventiveness in many of the sounds as well as a variation in the compositions here that make it fun to listen to even if you aren’t out for a night of clubbing. If music is going to make you go deaf, you might as well have fun while doing so.
Given the design of the SBS.1 speakers, I guessed that they would have an ample amount of headroom, and I was not disappointed. The snares had a visceral snap, the lead synths screamed uninhibitedly, and the razor-sharp sizzle of the hats showed that the tweeter had no trouble keeping up with the midwoofers. Likewise, the midbass of the midwoofers had no trouble keeping up with the subwoofer. The system could easily get louder than I am comfortable with, and my tolerance for loud music is likely a bit higher than average. I did not get a sense that the system was being pushed into distortion, and everything sounded clear as a bell. I am not sure if I reached the dynamic limits of the speakers, but I sure as hell reached the dynamic limits of my ears. I enjoyed listening to “Motive” on the SBS.1 speakers, but at such elevated levels, I was also relieved that it was over. The designer tells me that the speaker is heavily protected by electronic limiters and to go ahead and let them rip because they can’t damage themselves. That being the case, I would say if you are looking for something that can withstand irresponsible use of the volume knob such as at a party where the alcoholic beverages are flowing freely, these look to be a great choice; just try to put the speakers in a location where drinks will not spill on their fine satin finish.
One movie that I decided to watch using the SBS.1 speakers was the latest adaptation of “Death on the Nile.” I figured that an Agatha Christie whodunit with an all-star cast would be a good demonstration of a sound system’s dialogue intelligibility if there ever was one, but more than that, I generally enjoy Agatha Christie stories, so this was something I was looking forward to. A major movie like this one should have the best sound engineering that money can buy along with a top-shelf original music score, so it should stand as a good all-around test of a loudspeaker’s ability with film content.
“Death on the Nile” proved to have a flashier sound mix than I expected due to the heavily stylized direction, and the SBS.1 speakers were able to relay the bombastic tone that the movie was going for. I would have thought an Agatha Christie whodunit would be a bit more restrained, but I guess the story and characters are not thought to be enough to keep an audience’s attention nowadays. None of that can be held against the SBS.1 speakers which did an admirable job of bringing about the intended sound of this movie. Dialogue intelligibility was very good, and I had no problem understanding anything said by the characters, not even Kenneth Branagh’s over-the-top Hercule Poirot (most French people who have spent that much time in the English-speaking world do not have such heavy accents). Patrick Doyle’s elegant music score stands out as a highlight of this sound mix, and the SBS.1 speakers rendered it with a properly cinematic depth and scale. They proved that even smaller speakers could deliver a big-screen experience. I have had much larger speakers in my home theater, and these two little speakers plus their diminutive subwoofer partner didn’t leave anything to be desired as far as the sonic experience went. There are few speakers of their size that I could be enthusiastic about as a pairing for my 125” screen projection system but watching “Death on the Nile” with this system proved that I could enthusiastically, live with it.
For a sound mix with more emphasis on action, I watched 2021’s “Free Guy” starring Ryan Reynolds. In this big-budget action-comedy, Reynolds plays a non-player character in an open-world free-for-all game similar to “Grand Theft Auto” series. To his shock, he becomes aware of the lowly nature of his existence but then learns to use his plight to his advantage. While I had not yet seen “Free Guy,” the premise sounded fun and should set the stage for a fantastical sound mix that could be a great demonstration of the SBS.1’s ability to render big-screen action.
I watched “Free Guy” at a fairly loud level, and the SBS.1 gave a clean, dynamic presentation. I enjoyed the movie and felt that the SBS.1 speakers acquitted themselves beautifully for this lively and energetic sound mix. Effects, music, and dialog were well-positioned in the soundstage of the mix using just two channels, and I didn’t miss the center channel or surround channels at all. Of course, a phantom center works pretty well when the listener is seated at an equidistant location but not really anywhere else, so listeners with a wider seating area would want to use a physical center speaker. One interesting aspect of the SBS.1 is that you could turn it on its side for a horizontal orientation, and the design suggests it would work just as well on its side as upright, so if you needed a lower profile center, the SBS.1 could do that as well as any other center speaker design. By the same token, if you needed lower profile left and right speakers, you could use the SBS.1s on their side and it shouldn’t give up a thing in terms of sound quality. That is just one of the added benefits of its strong point source design. While I did not miss the center and surround channels watching “Free Guy” on a pair of SBS.1 speakers and the 10D sub, I do have to wonder how much the experience would be elevated if I had an entire surround sound system comprised of SBS.1s. It would be pricey, but I imagine that would have to sound tremendous.
James Larson is Audioholics' primary loudspeaker and subwoofer reviewer on account of his deep knowledge of loudspeaker functioning and performance and also his overall enthusiasm toward moving the state of audio science forward.
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