Kali Audio SM-5

Kali Audio’s latest three‑way speakers look unassuming, but represent a big step up in performance.

Back in SOS June 2021 I reviewed the Kali Audio IN‑5. It was the company’s first active three‑way monitor, and featured their dual‑coincident driver technology, in which a tweeter is located at the apex of the midrange driver diaphragm. The IN‑5 driver complement was completed by a relatively small 120mm‑diameter bass unit, and the whole system was housed within a modest, easily accommodated enclosure for nearfield use.

If you’re wondering why I’m recalling the IN‑5, it’s because the subject of this review, Kali Audio’s new Santa Monica SM‑5 active monitor, looks at first glance to be very similar. Its cabinet is of similar dimensions and the driver array, in headline terms, is the same. But despite the apparent similarities, and though it still qualifies as an ‘affordable monitor’, the SM‑5 is a fair bit more expensive than the IN‑5. So what differentiates them? The short answer, say Kali Audio, is that there’s considerably more expensive electronic and acoustic engineering integrated within the SM‑5, and that it consequently aspires to a significantly higher level of performance. The longer answer is... the rest of this review.

Business At The Back

I’m going to start around the back of the SM‑5’s black‑painted and substantially tree‑derived enclosure, where there’s a balanced XLR analogue input, an AES3 digital input and output (unusually, on BNC sockets) and an RJ45 network socket that enables connection to Kali Audio’s new Kali Control Panel application. This comes in macOS and Windows flavours and I’ll describe it a little further down.

The SM‑5 features both analogue and digital audio inputs, and a network port to allow the DSP to be controlled using the Kali Control Panel app.Downstream of the SM‑5’s inputs there’s analogue‑to‑digital conversion on the analogue inputs, followed by a DSP module that provides both the EQ functionality accessed through Kali Control Panel and the crossover filtering required to integrate the drivers. And following the crossover, the SM‑5’s amplification comprises Class‑D modules that provide a total of 225 Watts shared among the drivers. While the Kali Control Panel application offers the most comprehensive configuration options, the monitor can also be set up to a basic level using a rear‑panel rotary encoder that provides access to input sensitivity, and a DIP switch array that enables selection of some preset LF boundary and HF level trim options.

I don’t usually write about a monitor’s top and bottom panels, but those of the SM‑5 feature arrays of four M5 tapped inserts intended to provide bracket attachment points. Kali Audio clearly envisage the SM‑5 finding its way into Atmos monitoring systems, so they’ve done what they can to make ceiling, wall or frame mounting of SM‑5s a reasonably practical proposition. Atmos studio installation is becoming a factor in the design of nearfield monitors, and manufacturers that don’t integrate some appropriate bracket mounting points risk being left behind the curve.

Sound On Surround

On the front panel are the previously mentioned composite midrange driver and tweeter, the bass driver, and a letterbox‑style reflex port that blends into the lower circumference of the bass driver. Starting with the dual‑coincident mid/tweeter unit, one of the great benefits of the three‑way electro‑acoustic architecture is that bass and midrange drivers can be optimised for their specific roles rather than having to cover both. Bass/midrange drivers are fundamentally compromised at low frequencies because they have to reach up to the midrange, and (this will come as no surprise) fundamentally compromised at mid frequencies because they have to reach down to the bass. The relief from that compromise is immediately apparent in the SM‑5 midrange driver, because it has only a very small surround.

The roles of the surround in a bass/mid driver are to enable significant diaphragm excursion at low frequencies, while simultaneously dissipating the vibrational energy that propagates outward in the diaphragm at higher frequencies. It’s a tough job, and designers of bass/mid drivers probably spend a good proportion of their careers trying to find surround materials and geometries that can handle both roles without compromise. One of the most fruitful ways of optimising a midrange driver surround is to all but dispense with it. There’s typically no need for a midrange diaphragm to move very far, so the only role for the surround is the energy‑dissipation one, and that’s more about material characteristics than it is about generous geometry. So the surround on the SM‑5 midrange driver is no more than a few millimetres wide and actually, at first glance, it appears as if there’s no surround at all, because it’s so tightly integrated with the blend between the diaphragm and its waveguide.

Guiding Light

The mid driver’s roll surround is very thin, which minimises diffraction.Yes, you read that correctly, the midrange driver has a waveguide. In fact, the waveguide works for both the midrange driver and its concentrically mounted tweeter and, again, it’s the tiny midrange surround that makes that possible. One of the issues you see with tweeters concentrically mounted within bass/midrange drivers is that the necessarily large roll surround causes significant diffraction of the tweeter radiation. The midrange diaphragm works as an effective waveguide for the tweeter right up until the point where the surround happens, and that undoes all the good work. Take the surround away, though, and you can have a continuous waveguide for both drivers. That’s what the SM‑5 does. It’s a really neat example of electro‑acoustic engineering.

Before I move on, I’ll note that the midrange driver diaphragm, rather than being fashioned from a high‑tech wonder material, is made from paper. Even in the modern world of graphene composites, paper is still very hard to beat as a speaker diaphragm material — its particular combination of light weight, stiffness and ease of manufacture is genuinely hard to find elsewhere.

Highs & Lows

The SM‑5 tweeter is a 25mm aluminium‑dome device that, Kali say, employs a geometry designed to reduce the ultrasonic high‑Q resonance that’s often a characteristic of such tweeters. The measurement data I took showed no evidence of any high‑Q resonance below the 20kHz cutoff; there does appear to be an unexpected sharp dip at around 18kHz, but it looks benign as there’s no evidence that it’s a resonance feature (and there’s really not much music going on at 18kHz anyway). I’ll describe my measurements more fully further down the page.

The bass driver, like the midrange driver, sports a paper diaphragm and, as it’s optimised for low frequencies, incorporates a generous rubber roll surround. The driver appears to be of conventional manufacture, other than its dust cap being glued to the end of the voice‑coil former rather than to the diaphragm. This assembly quirk has become a bit of a Kali signature and it’s one I quite like for its logical engineering common sense. Kali say that the bass driver motor system incorporates a Faraday ring and non‑magnetic pole‑piece cap to reduce magnetic flux and inductance modulation. These are good things to have, and I’d expect the SM‑5 to demonstrate good distortion numbers as a result.

Kali Control Panel

Once installed (which is slightly finicky because it requires specific installation permission on macOS), the Kali Control Panel application quickly found the pair of SM‑5s I’d connected via their RJ45 sockets to my studio network switch. Kali Control Panel looks and feels slightly less sophisticated than other similar applications such as PMC’s SoundAlign, but the necessary functionality is all present.

Like the monitors themselves, Kali Control Panel is designed with multi‑channel monitoring in mind, and to that end it can accommodate Atmos systems up to 9.1.6, or custom formats with even larger numbers of monitors. Each monitor that the application discovers on the network is assigned a location by dragging it from the Discover list to the listening space alongside. Speakers can also be renamed and identified courtesy of a flashing front‑panel indicator, and multiple monitoring systems can be stored and recalled as presets. Each monitor can also be assigned an EQ, delay and level trim.

Once a monitor is assigned, the Control Panel’s eight‑band EQ functionality becomes available. Each band offers peak, first‑ and second‑order high‑pass and low‑pass, and high‑ and low‑shelf filtering, with frequency, level and Q controls. EQ curves can be created by grabbing and sliding the frequency ‘handles’ or defined through numerical entry of frequency, level and Q. It all works very smoothly. If a speaker remains connected to Control Panel over the network, EQ changes happen on the fly, but EQs can also be saved and uploaded to the speaker either over the network or by storing them on a USB memory stick. The SM‑5’s front panel incorporates a USB socket for EQ uploads.

Screen 1: The Kali Control Panel software lets you apply EQ according to personal preference and to correct for room acoustics.

The EQ is useful both as a means to mould the sound of the SM‑5 towards personal preferences and for room optimisation. Room frequency response data captured with, for example, FuzzMeasure (www.rodetest.com) or Room EQ Wizard (www.roomeqwizard.com) can inform the Control Panel EQ settings to compensate for unhelpful trends and specific studio acoustic issues. Without wishing to spoil my subjective feeling about the sound of the SM‑5, I found when listening that a little boost around 150Hz was useful, and at the same time I used the EQ to compensate for a couple of known low‑frequency modes in my studio room. Screen 1 illustrates the curve I came up with, and Diagram 1 shows its effect on the in‑room frequency response of one channel at the listening position. The red curve is pre‑EQ and the blue curve is post‑EQ. Given more time, I’m sure I would have refined the EQ further, and maybe added a few more filter instances.

Diagram 1: The in‑room response of the SM‑5, with EQ bypassed (red trace), and with the EQ settings from Screen 1 applied (blue).

Measurements

Diagram 2: A quasi‑anechoic measurement of the SM‑5’s on‑axis frequency response (red trace) and distortion, measured at 1m at 80dB SPL. Second‑harmonic distortion is shown in green, third‑harmonic distortion in blue.

As usual, I took some quasi‑anechoic (using a ground plane technique with a 2m mic distance) measurements of the SM‑5. Diagram 2 shows the axial frequency response and distortion, measured at 80dB SPL at 1m. The response is nicely linear with no major flaws (apart from the previously mentioned and probably not that significant suck‑out at 18kHz) and the distortion is generally very low, pretty much bouncing along the measurement noise floor. Diagram 3 is a repeat of Diagram 2 but with the SM‑5 working much harder at 90dB SPL. The distortion rises as expected but is still very well controlled. The distortion performance of the SM‑5 is generally very impressive.

Diagram 3: As Diagram 2, but at 90dB SPL. The distortion rises accordingly, but is still well controlled, and impressively low for a ported monitor.

Diagram 4 shows how the frequency response varies with mic position: 20 degrees off‑axis horizontally and ±10 degrees vertically (with the speaker in portrait orientation). The result, a very tight bunch of curves, is excellent and illustrates one of the huge advantages of dual‑coincident drivers: consistency of dispersion.

Diagram 4: Comparing the on‑axis frequency response (red trace) with measurements taken 20 degrees to the side (blue), 10 degrees above (yellow), and 10 degrees below axis (purple).

Finally, Diagram 5 illustrates the results of placing a measuring mic very close to the bass driver and the port exit respectively, and then driving the monitor both gently (equivalent to 80dB SPL at 1m) and quite hard (90dB SPL at 1m). Looking at the driver first (the red and green curves, which are normalised), there’s very little difference between 80dB and 90dB. This is as it should be, apart from a little thermal compression between about 90Hz and 250Hz, and a reduction in the depth of the dip at the port tuning frequency on the 90dB curve. The reason for that dip difference can be seen in the port close mic curves, again for 80dB (blue) and 90dB (orange). At 90dB the port airflow has begun to become turbulent, so the port output drops relatively by a couple of dB: the port Q reduces as the monitor works harder, so the port makes less of a contribution to the output.

Diagram 5: Close‑mic measurements of the bass driver, with the speaker playing at 80dB SPL (green trace) and 90dB SPL (red trace) at 1m. Close‑mic measurements of the port are shown in blue (80dB SPL) and green (90dB SPL). The results are normalised, and show impressively consistent port behaviour at different SPLs, with minimal organ‑pipe resonance.

Now, I should emphasise that this kind of port compression effect is generally a characteristic of reflex loading, and all such monitors will ultimately display it to some degree (all ports run out of laminar airflow capability at some point). So this is all more educational observation than criticism. Furthermore, the port response curves illustrate an element of the SM‑5 port performance that demands great praise: its lack of any significant midrange organ‑pipe resonance above the 45Hz tuning frequency. That’s a definite win.

It has the resolving power of significantly more expensive monitors — and a slightly NS10‑like way of making midrange details explicitly audible.

Listening In

I initially found listening to the SM‑5 to be a slightly mixed experience. Genuinely exceptional (striking, even) detail, clarity and stereo image focus and resolution was accompanied by a tonal balance that seemed somewhat light on lower midrange. Voices lacked an element of warmth and body, and, with my bass player hat on, I wanted to hear a bit more neck pickup. Electric basses sounded ‘all bridge pickup’. In addition, the SM‑5 to my ears possesses a hint of ‘cuppy’ coloration in the midrange that I particularly noticed on naturally recorded voices. It’s not a deal breaker, and on much material perhaps wouldn’t really be significant at all, but once you hear such things you can’t unhear them. This was the point at which I began to use the Kali Control Panel EQ, and adding a little energy around 150Hz not only nudged the overall balance to somewhere much nearer my liking (and I think more usefully neutral in translation terms), it also masked significantly the coloration I’d heard. Once the balance was more to my liking, I was much less conscious of the coloration and could appreciate the SM‑5’s exceptional reproduction of mix detail. It has the resolving power of significantly more expensive monitors — and a slightly NS10‑like way of making midrange details explicitly audible. There’s also a highly satisfying coherence to the entire SM‑5 midrange and high‑frequency experience, and speaking of high frequencies, I wasn’t particularly aware of anything missing at 18kHz. It’s tempting, of course, to ascribe the subjective coherence of the SM‑5 to the integrated nature of its dual‑coincident driver. So tempting, in fact, that that is exactly what I’m going to do. My feeling is that the consistent dispersion and synchronised timing of midrange and high‑frequency output — fundamental characteristics of a well‑designed dual‑coincident driver — pay great dividends.

The more I listened, the more I came to appreciate the SM‑5 in the midrange and high end, but I liked its efforts at low frequencies right from the start. It sounds as if the designers made a conscious choice not to be too greedy with low‑frequency bandwidth extension (possibly because the bass driver is relatively modest of diaphragm area), and that’s a laudable decision, I think. I’d much rather have accurate and informative bass with slightly limited bandwidth than massively extended bass that’s light on actual subjective insight. The SM‑5 is notably lacking in the pitch, timing and dynamic uncertainty that can sometimes trouble reflex‑loaded monitors. It will probably never shake the walls with bass, but it will most likely enable a decent low‑frequency mix to be built — and that’s way more important.

I was unsure of what to expect when I first unpacked the SM‑5s. Conceptually, they seemed rather too close to the IN‑5s. How much better could they be? Well, acoustic memory is not always entirely reliable, but I don’t remember the IN‑5s leaving as great an impression as the SM‑5s have. The SM‑5 is not entirely free of quirks (what monitor is?) but it is hugely likeable and could easily earn its keep in a wide variety of studio and mix contexts — all the way up to professional Atmos mix studios. It is a great example of relatively cost‑effective contemporary electro‑acoustic design and engineering, and Kali Audio ought to be very proud.

Information

£3398 per pair including VAT.

sales@kaliaudio.com

www.kaliaudio.com

$3398 per pair.

sales@kaliaudio.com

www.kaliaudio.com

When you purchase via links on our site, SOS may earn an affiliate commission. More info...