QSC K Series

A sturdy steel grille covers the front of the speaker and there is a layer of black acoustic foam behind this, so the driver components appear to be well protected against physical damage or the occasional moisture-related mishap. The enclosure itself is made from moulded ABS, although it initially looks and feels more like traditional texture-painted ply. The overall impression with the K8 is of a well-made, strong little cabinet, and the slightly concave shape of the front gives a good deal of rigidity to the grille, with almost no chance of the front being dented inwards.

The K8 has a generous, single, top-mounted handle, which is both comfortable and secure (although this box is so small and light that it probably wouldn’t matter if it didn’t even have one), and the bottom panel accommodates a Euro-standard 35mm pole socket, which can be adjusted to achieve different coverage angles. Behind the grille are an eight-inch cone driver and a 1.75-inch diaphragm compression driver mounted on a conical horn structure. The K8 has a 105-degree all-round dispersion, which works well in the sort of smaller-scale applications you’d tend to be using this setup for. It’s not designed to throw immense SPL to the far end of a football stadium, but I found the output to be even and well balanced, and I wouldn’t argue with the published figures.

My favourite thing about active speakers is that all these finer points are sorted out by the designers and all I have to do, within reason, is shove in an XLR and turn the music up. Apart from the basic control and protection functions, the clever processing that goes on inside these speakers can be what sets one make/model apart from another. The K8 contains a couple of QSC’s own tricks called DEEP (a specialised application of the in-built driver excursion limiting feature) and Intrinsic Correction, which, as I understand it, applies specific signal correction based on the individual characteristics of the drivers and waveguides used (in other words, it customises the amp’s performance to exactly match the driver/enclosure setup).

In terms of connections and controls, the K8 is straightforward enough, but there are two input channels available, which can be mixed, and there are direct outs for both channels, plus a mixed output. Channel ‘A’ can accept either line- or microphone-level signals and is equipped with one of those combined jack/XLR sockets that is so useful for portable live work, and a direct linked output appears on an XLR just below it. The channel input sensitivity is adjusted by a large rotary control, which is partly recessed and therefore well protected by the panel surface, and the post-control signal feeds the amp section and is also sent to the line out connector. I’ve grown to appreciate these mic/line inputs on active speakers because for simple applications (solo/duets, school fêtes and the like), a mic can be plugged straight in with no additional gear needed.

What you also get with the K8 is a second input. Channel ‘B’ doesn’t have a mic preamp, but it does have a combi jack, same as channel ‘A’, and is also furnished with a pair of unbalanced RCA phono inputs for connecting replay sources, which will mix (summed to mono, of course) with whatever’s plugged into the balanced input. The ‘B’ channel’s output is also fed to the internal amps and the line output, and the whole arrangement offers useful setup options for linking multiple speakers together, or for sending a mixed signal to a remote system or monitor.

The LF and HF response can be shaped to suit the application by way of two little slide switches. LF response can be good old ‘Norm’ or it can be set to ‘Ext Sub’, which introduces a 100Hz high-pass filter when the K8 is used with a subwoofer. There is also another setting, which brings DEEP into play for extended bass response to partly compensate where there is no sub. The HF response can be set to ‘Flat’ or ‘Vocal Boost’, which is intended for announcements or any application where spoken material needs to cut through and music fidelity is not so important. I had a quick listen to the K8s on their own, at not much more than background music level, and I liked the way the DEEP circuit filled out the bottom end without sounding boom-y or muddy. The Vocal Boost setting also does just what it says and adds a degree of clarity, which would be a useful option in a simple speech-only setup if there were no external mixer involved.

The most instantly noticeable thing about the KSub is just how easy it is to move around and manhandle. For a powerful active sub, it’s incredibly light at a bit under 34kg, and it has a very secure, comfortable handle on each end (that’s actually top and bottom if it’s standing upright), so it’s ever so easy to lift up and carry. Four large swivel wheels are mounted on the rear, and it’s a breeze to push around.

In terms of performance, the KSub is rated as having a 48Hz to 134Hz response to the -6dB points, with a maximum SPL of 130dB at one metre. The enclosure is constructed from birch ply and has a good-quality textured paint finish, which feels very hard and didn’t exhibit any scratches or marks after a pub garden gig and a couple of trips in the van without the benefit of any protective covers. The front of the KSub is mainly a solid panel, so there’s no need for a grille, and like the K8, it has a solid feel and an air of quality construction.

The KSub’s control panel is similar in layout to the K8 version, in that it has ‘A’ and ‘B’ inputs, each with a direct link output, but the two (combi XLR/jack) inputs are always summed together and the summed signal is then controlled by the sensitivity knob on its way to the amp section. Like the full-range units, the KSub can operate in DEEP mode if extra lows are required, and a polarity invert switch is also provided for improving bass output under certain speaker placement conditions — for example, if the sub has to be located some distance from the mid/high speaker, or where two subs are placed apart with one further back than the other. The front panel LED has the same display options as for the K8. And, of course, the sub benefits from the same DSP protection and enhancements as the rest of the range.

The marquee didn’t have a floor, so the subs were sitting on the grass. A couple of my patent plastic spacers soon had them level and secure, and we screwed in the mounting poles, ready for the K8s. At this point, it became clear that the poles supplied with the system were far too short, as with the subs on the ground the K8s were around face height and I wanted them about a foot higher. Luckily, the additional ‘van trivia’ had included my pair of adjustable screw-base poles, so we were able to achieve a good operating position with the top cabs above head height. I much prefer the screw-in pole bases to the 35mm drop-in type, which are often either too tight or too sloppy and seem to vary between manufacturer. The poles attached very firmly to the subs, and with only the little K8s on them (12.2kg apiece), everything stayed safely in place.

The K8 mounting sockets are an adjustable type and the speaker angle can be tilted down by 7.5 degrees when the cabinet is in place on the pole or stand. This small change in angle can make quite a difference in some venues, and the QSC mounting system is a much neater way of doing this than using external metal adaptors.

Connecting up the K Series speakers took only a few minutes. I ran separate feeds to the left and right ‘stacks’ and connected them into the ‘A’ inputs of the KSubs, set to flat EQ, each with a link to the K8 above, using the Ext Sub setting. I ended up running the sound in mono anyway, so I could have saved a bit of time and wire by linking across using the K8’s direct output, but we were ready to power it all up and I was keen to have a listen. When trying out speakers for the first time, I always play the same recorded tracks, just to see how they grab me, and so I spent the next 20 minutes listening to the sort of material that tells me how much I like the system.

The K8s and KSubs were impressive right from the start, and although I couldn’t check out the coverage, I could appreciate the clarity and power, which this compact rig obviously has in abundance. The British summer weather was truly appalling, so we stayed in the marquee with three sides down and I had a great time seeing how loud I could play the main theme from The Abyss, which has a big dynamic and tonal range and is a good test of what the rig will do when driven on or near the limiters with sustained notes. Almost anything can sound OK with punchy drums and a well-produced track, but some of my test CDs are uncompressed live recordings, and if I can hear deep thunderous timps and basses and clear, clean orchestral brass soaring over the top without squashing, I reckon I’m listening to a decent system.

The K Series performed beautifully all day, and we had a number of complimentary remarks about the sound from performers and audience. I didn’t have any trouble in getting everything I wanted from the system, and I never felt I had to fight it or compromise on anything. I suppose a marquee is a pretty good place to run live sound — much better than your average village hall (sorry, community centre) — but it was nevertheless an easy ride on the desk and we didn’t exactly keep everything to a Sunday afternoon level. We had the whole backline and kit miked up, and everything from five-part country harmonies to electric fiddles and some younger synth-heavy acts to deal with.

Although before hearing them I initially wondered whether a pair of eight-inchers would really be able to deliver with this gig, I have to say that they balance really well with the KSubs, and I like the scalability of the system. I could well imagine using anything from a single K8 for public address to a pair of them for background/party music, moving up to one or two KSubs for a full-blown gig like the aforementioned marquee job.

For a bigger venue, I’d love to try out the larger K10 or K12 full-range speakers, perhaps with an additional pair of KSubs to provide a really big bottom end. But for smaller venues, the K8-plus-KSub combination is a cracking little system and should find many friends in the portable live sound world.  0