Kombo Audio Kombo

With battery operation and wireless connectivity built in, could the Kombo be the ultimate ‘go anywhere’ PA?

I wrote about the Yamaha StagePas 200 battery‑powered portable PA/busking speaker back in SOS May 2023, and began my review with an assertion that there aren’t many such backline products around. So I should have known that I’d almost immediately happen upon another one, the Kombo, which is the subject of this review.

The Kombo is the product of a Danish startup company called Kombo Audio, and while it is primarily aimed at the same kind of applications as the previously mentioned Yamaha product, it introduces a few unusual twists of its own — the main one being that it’s specifically designed for wireless connection to its instrument and mic inputs.

To enable this, the Kombo ships with two wireless transmitter belt packs (one with an instrument input and one with a mic input), and two receiver modules. These attach to magnetic ports located either side of the rear of the Kombo cabinet itself, and electrically connect automatically. Extra transmitters and modules can be purchased to enable up to four wireless inputs to be used, and the Kombo also offers three conventional wired inputs (one mic, one instrument, one line) so, in theory, a seven‑piece band could busk with a single Kombo. There’s more: because the Kombo also provides a Bluetooth audio connection, that seven‑piece could also play with backing tracks streamed wirelessly from a smartphone.

...the Kombo ships with two wireless transmitter belt packs (one with an instrument input and one with a mic input), and two receiver modules.

The Box

The Kombo is usefully compact in dimensions and feels very solidly put together. All the enclosure edges and corners are coated in a matte‑black rubberised bumper finish, and its front grille is black‑painted, perforated steel. I can see the Kombo surviving with no trouble at all the rigours of a life of busking or in makeshift gig or rehearsal spaces. The slightly inset side, rear and end panels of the enclosure are finished in a contrasting grey leather effect, and it all makes for a unique and quirky appearance. A generous carry handle is inset in each enclosure end panel and, while my review sample lacked this detail, future production will, I’m told, replace the bottom carry handle with a pole‑mount hole.

One slight downside of the Kombo’s impressive build quality is weight. At 13kg the Kombo is not an insignificant lift, and certainly not something you’d want to carry a long distance from the car park to the town‑centre busking site. It is, however, perfectly proportioned to fit on a small sack‑truck style trolley. And I guess I’d rather have a busking amp that’s built to last than it be a few kilograms lighter.

One element of the Kombo that contributes to its weight is, of course, the battery. A lithium‑ion device, this is supplied uninstalled and has to be inserted in a rear‑panel recess where it connects to a multi‑pin terminal block and is held in place by a Velcro strap. The Kombo can’t be used without its battery installed. Battery charging is achieved through a mains power supply that connects to the Kombo rear panel using a 24V DC connector. Kombo Audio claim a 20‑hour battery life, which ought to be adequate for even the most profitable of busking spots. The Kombo wireless receivers and transmitters are also powered by rechargeable batteries, and can be charged, two at a time with a supplied splitter cable, from the USB Type‑A charger output on the Kombo rear panel. The receivers and transmitters are fitted with micro‑USB charging inputs.

When I first came across the Kombo I imagined that Bluetooth might be employed for its wireless connection from transmitter to receiver. I was completely wrong because, in fact, Kombo Audio have developed a proprietary dual‑band (5.2GHz and 5.8GHz), eight‑channel wireless protocol for the Kombo that they say offers 30m maximum range and transmits uncompressed audio. The wireless protocol also, say Kombo Audio, results in just 7ms latency, although the Kombo’s internal DSP potentially adds another 3ms, for a total of 10ms. It’s perfectly workable latency for live performance. One useful possibility that the Kombo wireless protocol enables is the connection of individual transmitters to two receivers. This means that either stereo sound or simply extra volume can be had by adding a second amp/speaker unit.

Behind its front grille, the Kombo sports a single 200mm coaxial driver comprising a paper‑diaphragm bass/mid element and a compression tweeter. The coaxial arrangement of the two elements helps ensure both phase alignment and consistent dispersion. The bass/midrange driver is reflex loaded in the enclosure by twin front‑mounted ports. An Infineon Technologies Merus Class‑D amplifier module provides 160 Watts for the bass/midrange driver and 40 Watts for the tweeter. Kombo Audio claim a 60Hz‑20kHz (±3dB) frequency response and a maximum continuous output level of 110dB SPL at 1m. These aren’t specs that are going to blow the roof off a stadium, but for the intended small‑scale gig, rehearsal or busking application they’re perfectly adequate.

Wireless For Sound

The two transmitters and receiver packs supplied, and available as additional extras, with the Kombo are not the same. One, known as a KAM (Kombo Audio Microphone), provides a female XLR connector and a phantom power selector button on its transmitter body. The other, the KAS (Kombo Audio Strings), is intended for guitars and other instrument‑level signals and provides a high‑impedance jack input and a feedback suppression button (which simply flips the polarity) on its transmitter body. Both KAM and KAS transmitters also incorporate a belt clip, an on/off button, a wireless channel selector and a battery level indicator.

The Kombo ships with two wireless transmitter/receiver pairs: one designed for mics, with an XLR input, and one designed for instruments (pictured), with a high‑impedance jack socket.

The KAM and KAS receiver elements are also different. The KAM receiver offers a range of adjustment parameters, selected sequentially by pressing left and right buttons. These are volume, FX1 (compression), FX2 (reverb), high EQ, mid EQ and low EQ. The KAS receiver offers the same set of named parameters, selected in the same way, but the behaviour of FX1 and FX2 is modified by an extra slide switch, with Acoustic, Guitar Amp and Bass Amp options. In Acoustic mode, FX1 offers Reverb and FX2 Tone Warmth; in Guitar Amp mode, FX1 offers Drive and FX2 offers Reverb; in Bass Amp mode, FX1 offers Drive and FX2 offers Compression.

In both the KAM and the KAS, the level of a selected parameter is adjusted by turning the outer rim of the receiver module. A circular array of LEDs illuminates sequentially to indicate the parameter level, and a group of parameter settings can be saved by pressing the right parameter button so that selection returns to the first parameter. I found the whole process a little counterintuitive at first, but once understanding and memory kicked in it became second nature.

In Use

In terms of their subjective quality and character, the effects offered by Kombo fall, to my ears, into the ‘uncomplicated but effective and instantly usable’ category. They’re unlikely to win awards, and you probably won’t be using the Kombo as a recording amp (never say never, though), but dialling in a touch of reverb on voice, a smattering of drive on guitar or a dose of compression on bass does exactly what’s likely to be appropriate in the context. It’s easily possible to get usable and satisfying sounds very quickly, and that’s really the whole point.

The microphone transmitters in action.

The wireless receivers attach and connect magnetically to the back and sides of the speaker. Up to four can be installed at a time.Part of the satisfaction of the sounds available from the Kombo is a result of its fundamentally well‑sorted electro‑acoustics. Apart from a slight nasal tendency, which primarily results I think from an inherent upper‑mid tonal emphasis, the Kombo displays a pleasingly natural character on voices and guitars, and plays a good level of high‑frequency detail without much evidence of compression‑driver harshness as it gets louder. The other side of the midband coin is, of course, that voices will cut through. Basic vocal intelligibility from the Kombo is very good. The Kombo does struggle a little with loud bass fundamentals, but that’s to be expected considering its compact dimensions and relatively small bass driver, and anyway, impressing with epic bass is not really what the Kombo is about.

Apart from mentioning that they exist, I’ve not so far covered the Kombo’s three wired inputs, but that’s partly because there’s not a great deal to say. The inputs comprise two unbalanced jacks and one balanced XLR socket, each with an associated gain knob, located on the rear panel. The wired inputs have no effects or EQ facilities, which perhaps is a shortcoming, especially for the mic input where you might want the wired vocal input to share the same reverb as the wireless mic input. The line and instrument inputs I could see being used with upstream effects, so perhaps the lack of anything integral to the Kombo is not that big a deal. While I’m on the subject of the rear panel, there’s also a main volume control to be found there, along with a Bluetooth connection indicator and a ‘Mute Everything!’ panic button.

Measuring Up

I fired‑up FuzzMeasure to investigate a few of the acoustic characteristics of the Kombo. Without hiring a big empty space (or spending £100k on sophisticated analysis kit), it’s not possible to accurately measure the anechoic frequency response of a full‑range loudspeaker, but even doing some simple in‑room measurements can reveal useful information. So, to that end, Diagram 1 shows the smoothed, close‑mic axial frequency response of the Kombo with a 30‑degree off‑axis curve overlaid. The interesting thing about this is not the somewhat lumpy response curve (that’s partly the result of reflections in the room) but the relatively small difference between the on‑ and off‑axis responses. This suggests that the Kombo has usefully wide dispersion, and considering its intended role, that’s a good thing.

Diagram 1: The Kombo’s frequency response, measured on‑ and off‑axis (red and blue traces, respectively).

Diagram 2 shows the effects of the KAS (‘string’) transmitter/receiver EQ. The ‘flat’ curve is in red, with bass, mid and high at maximum and minimum in blue and green respectively. The curves reveal the expected results, although it’s also interesting just how much gain the LF EQ applies at maximum boost (14dB at 60Hz), which can result in the Kombo audibly struggling somewhat with noticeable levels of distortion and port noise. I’d employ the LF EQ with restraint.

Diagram 2: The Kombo’s EQ, set to flat (orange trace), and with all three bands at maximum cut (green) and boost (blue).

Finally, Diagram 3 illustrates a quick check of the total in/out latency through the KAM transmitter/receiver. The two events in the impulse response show a timing reference of the recording interface output (a Focusrite Dante interface sharing a network) at 20.5ms, and the Kombo output arriving just before 31ms. The ‘flight time’ of the acoustic energy leaving the Kombo speaker and arriving at the microphone will also be embedded in the measured 10.2ms, so Kombo Audio’s claim of 10ms latency seems justified.

Diagram 3: A measurement of the Kombo’s total in‑to‑out latency.

I grew to admire and like the Kombo very much while it was in my possession.

I grew to admire and like the Kombo very much while it was in my possession. It’s a smartly designed and engineered product that provides an effective and innovative solution to a fundamental need. I can’t see many gigging, busking or rehearsing musicians not taking to it straight away. It sounds good, plays suitably loud with great clarity, has great versatility, and the wireless features work well once you have your head around how they’re set up and configured. It’s a very impressive and engagingly quirky first product for Kombo Audio.