d&b audiotechnik SL-Series Large- Format Line Array

by Vince Lepore
in Road Tests
d&b audiotechnik’s new GSL line array comes in 80- and 120-degree dispersion versions.
d&b audiotechnik’s new GSL line array comes in 80- and 120-degree dispersion versions.

Twelve years after debuting its J series, d&b audiotechnik introduces its new SL-Series flagship line array, which builds upon J’s strengths and propels the company into the future. In January, I traveled to Germany for a close-up, hands-on look at this next-generation, large-format speaker system. And with the company’s new Soundscape object-based immersive audio system, 2018 is shaping up to be an impressive year for d&b.

Figure 1: “X-ray” style view inside the GSL enclosure

‡‡         The SL-Series

There are four loudspeakers that make up the GSL-System, of which the GSL8 and GSL12 form the core. Both are 4-way boxes that are identical aside from their horizontal dispersion pattern. Like J8’s and J12’s before them, the GSL8 is an 80° box and the GSL12 is its 120° equivalent used for near- or mid-field applications. Inside the GSL cabinets, the low frequency section consists of dual forward-facing 14-inch drivers and two side-firing 10-inch drivers, both utilizing a bass reflex design (See Fig. 1). The mid-frequency section consists of a single horn-loaded 10-inch cone driver; the high-frequency section consists of three 1.4-inch exit drivers housing 3.4-inch voice coil diaphragms.

The complementary subwoofers are offered in two versions, the SL-SUB (shown here) has flying hardware, while the SL-GSUB is intended for ground-stacking.

‡‡         The Lowdown

Low-frequency reproduction is handled by the SL-SUB or SL-GSUB. The only difference between the two? The SL-SUB has rigging hardware while the SL-GSUB is meant to be ground-stacked. Both subwoofers consist of two forward-facing 21-inch woofers and a single, rear-facing 21-inch driver that results in a cardioid pattern. One of d&b’s primary design goals for the SL subs was to create a single enclosure that matched the combined response of a J-SUB and a J-INFRA. Overall, they succeeded in achieving that goal, reducing the number of subwoofer cabinets needed and simplifying a d&b subwoofer deployment.

‡‡         Amplification

Having looked closely at the inner workings and driver arrangement of the GSL8 and GSL12, one could reasonably assume that these 4-way cabinets would require four channels of amplification and associated DSP. However, in true d&b fashion, the GSL’s are powered by only two amp channels, making them incredibly efficient in terms of amplifier power and signal processing. You might think the SL would require an entirely new amplifier platform. Fortunately for existing d&b owners, the entire SL family (including subs) are powered by the D80 amplifier, so an entire 12-box hang of GSL’s can run on just six D80s housed in the 6 x D80 Touring rack. For the SL subs, one amp channel is devoted to powering the dual forward-facing 21’s, while the second channel powers the rear-radiating 21.”

New flying hardware simplifies setups.

‡‡         The Listening Tests

I headed to Stuttgart’s 15,000-seat Hanns-Martin-Schleyer-Halle to preview the SL-Series in its natural habitat. I was thankful for the opportunity to preview the system in an arena rather than a highly-controlled listening environment. The first listening test consisted of a ground-stacked set of four GSL’s next to a ground-stacked set of four J’s.

We switched back and forth between the GSL and J systems, focusing mainly on what was coming off the rear of the cabinets. The difference between the two was nothing short of stunning. As with most modern loudspeakers, the J’s had a good deal of low-mid energy firing off the back of the boxes. The GSL’s — on the other hand — had a very controlled dispersion, even behind the box. Thanks to the side-firing 10-inch drivers (which couple in the front but cancel in the rear), d&b was able to achieve pattern control over the elusive low midrange, making the GSL’s cardioid throughout their entire operating range. It is an impressive feat of loudspeaker engineering and a major differentiator between J’s and GSL’s. While the GSL’s are significantly quieter in the rear of the box, it is also worth noting that they have substantially more headroom in the LF and HF bands, making them extremely powerful for large events with high SPL requirements.

Our second set of listening tests focused on a single 12-deep hang of GSL’s. This afforded the opportunity to walk the arena and get a sense of the sonic character of the system. The hang was surprisingly consistent from the front to the back of the room, thanks in part to d&b’s ArrayProcessing technology, which applies a combination of IIR and FIR filters to achieve a target frequency response across the listening area.

In addition to walking the room front to back, I was eager to walk off-axis of the system because of the cardioid nature of the array. What I found was very interesting. As I walked off-axis into what would be the outfill zone, I heard something different than what I typically experience. With most systems, the tonal balance changes dramatically off-axis, as the high frequencies fall off more quickly than the mids and lows. In the case of the GSL’s, the tonal shift was not as noticeable, and walking off-axis sounded more like a straight level reduction.

Having recognized this, I was certain that the transition between the main hang and the outfill hang was going to be improved. Sure enough, once the outfill hang was turned on, the transition between the two was minimal. Certainly, there are still variances and comb filtering effects between the two hangs and there is no way to completely eliminate those, but the GSL’s cardioid pattern helped minimize the impact of the transition.

As we continued listening through a bunch of different styles of music, I found myself asking “Are the subs on?” The GSL’s produced a lot of low-end, and the system was playing tricks on me. In fact, the subs had not even been turned on, so we had yet to hear the full extent of the system. Once the SL subs were added in with the GSL’s, the true power of the system was revealed. Listening to the system at very loud volumes to see how it would perform as it reached limiting was quite impressive. The system remained stable and maintained incredible clarity, even at a very high SPL.

A 12-box hang of GSL enclosures

‡‡         Rigging and Transport

SL is a fully packaged system, and as such, comes equipped with all the appropriate transport and rigging hardware. While it is outside of the scope of this article to cover all the bits and pieces, the most interesting development is d&b’s new compression rigging method. In addition to the traditional tension rigging, where splay angles between cabinets are set with pins and the system is curved while being flown, the compression method lets the system be flown completely straight and compressed into its final shape once in the air. The compression method uses either an additional chain hoist or a manual winch to compress the array to pre-defined angles. The benefits of the compression method are many, but the main benefit is that the array flies straight. The footprint required to fly a large array is reduced dramatically, as is the physical labor required. While the tension method is still an option for GSL’s, I expect most companies will opt for the compression method.

‡‡         Final Thoughts

In the time I spent listening to the SL-Series, I found it to be a natural evolution, an incremental but important improvement over existing d&b technology. The system sounds fantastic, but let’s face it, most high-end manufacturers make excellent sounding systems in 2018. What sets SL apart is the cardioid directivity, the increased headroom, the ArrayProcessing algorithms, improved rigging options and the d&b workflow tools that surround it.

A sound system is only as good as the tools used to design and deploy it. And d&b audiotechnik has the history, the support and the tools to manufacture a system of this caliber and equip users to deploy it properly. It will be exciting to experience what engineers are able to do with SL-Series systems over the coming years.

A 15,000-seat arena provided a real-life listening environment.

At a Glance

Like the J-Series…But Different

The new d&b GSL8 and GSL12, like the J8 and J12, have 80° and 120° horizontal dispersion, and the same D80 amps powering the J Series can be used for the GSL8, GSL12 and companion SL-SUB/SL-GSUB subwoofers. But a key difference could be heard in a listening test. The GSL’s are significantly quieter in the rear of the box. When set up as arrays, a walk-around also reveals fewer changes in tonal balance as one moves into the outfill zone. The GSL8 and GSL12 also provide ample low-end, even when the SL-SUB/SL-GSUBs aren’t on.

d&b SL Series

PROS: Cardioid directivity, increased headroom, ArrayProcessing algorithms, improved rigging options, d&b workflow tools, ability to be powered efficiently by existing D80 amps.

CONS: None



  • 80° Horizontal Dispersion


  • 120° Horizontal Dispersion


  • Designed to be flown


  • For ground-stacked setups

Manufacturer: d&b audiotechnik

More Info: www.sl-series.com