In this, on-test article, we test the Kali Audio IN8, an ultra-affordable, dual-concentric, 3-way monitor. A combination which is so unusual it may be unique. However, while it may not have any direct competition, is it any good? We investigate.
Two-way or three-way? The advantages of a three-way format are easy to appreciate, a driver that performs well at low frequencies is rather different to one which operates well up in the midrange and a design that uses a bass-midrange driver usually involves bringing the crossover frequency down into the 1-2KHz range, right where a lot of crucial information sits. Introducing a third, midrange driver allows the bass driver to do bass, the tweeter to, err tweet, and the middle of the midrange can be kept clear of the crossover.
Unfortunately, things aren’t quite that simple. A three-way design is more complex and there is far more to get right. Anyone who has ever dealt with three sets of variables will appreciate that it’s a lot more than 50% more complicated than two, so when designing an inexpensive monitor, three-way is not the route to an easy life.
Two-way is very much the order of the day when designing a competitively priced monitor and when we tested the Kali LP6 we found an extraordinarily good value, two-way monitor. The IN8 are priced at $399 each and considering the nearest equivalent design we can think of is ten times this price (more on this later) the IN8 is rather on its own.
Construction
The IN8 shares similar construction as the LP series, using wrapped MDF and a plastic baffle. The cabinet construction is a little on the light side but fit and finish are both excellent, the porting is to the front and shares the same Low Noise design as the LP series.
The rear panel has XLR, TRS and RCA analogue inputs, with accompanying attenuator, an IEC AC socket, power switch and a row of dipswitches with preset filters to compensate for various room placements and voicing options. The setting for these switches is illustrated by some nice, clear diagrams on the rear panel. So far, so self-explanatory,
Amplifiers And Drivers
These active speakers are driven by a trio of class D amplifiers 60W for the LF and two 40W amps for the MF and HF drivers. The crossover frequencies are at 330Hz and 3KHz leaving almost a full decade of the information centred around 1KHz to the midrange driver.
The drivers themselves are a coated paper 8” bass driver and a dual concentric arrangement of 4” midrange and soft dome tweeter and it is this dual concentric complement of drivers, which makes this monitor so unusual and so interesting.
Dual Concentric Designs
Most of us are aware that having audio being reproduced by multiple drivers from multiple points in space causes time of arrival differences resulting in comb-filtering effects. A single driver behaves more like a point source and doesn’t suffer from these effects but covering the full spectrum at a reasonable level isn’t really possible. Mounting an HF driver in the centre of a larger bass/mid driver offers a practical way to get a full range point source monitor.
Tannoy are of course the most famous name associated with dual concentric monitors, in their case mounting a horn loaded tweeter in the centre of a large bass/mid driver. Presonus’ Sceptres are an example of another take where a horn is mounted in front of the bass/mid driver but the arrangement presented by Kali is a soft dome tweeter mounted in the centre of the midrange driver, inside the voice coil of the midrange driver.
One of the benefits of a dual concentric design is the elimination of the time of arrival differences between drivers in different points in space. This should result in a wider sweet spot. That’s may well be true but I’m very much of the opinion that the room affects imaging more that the monitor does. One thing it does mean is that the IN8 can be used in landscape orientation.
The physics of this dual concentric arrangement is seductive but it’s not without issues. In this arrangement, the cone of the bass/mid driver is also the waveguide of the coaxially mounted HF driver. At short wavelengths, small discontinuities in the typically smooth surface of a waveguide cause diffractions and re-radiation. A second issue is that of doppler shift causing modulation of the HF driver’s output.
Doppler Shift And Modulation
This doppler modulation is an interesting case as it is inherent to the design of a two-way dual concentric driver. If the waveguide of the HF driver is moving backwards and forwards as the tweeter’s output propagates across it, it will cause a pitch modulation. For example, if you were to play a 10K tone and a 40Hz tone simultaneously from a 2-way dual concentric driver the 10K tone would be heard to have a 40Hz vibrato applied to it! This issue becomes more pronounced as lower frequencies are reproduced.
This is where the wisdom of this three-way design of the IN8 becomes apparent. While the issues introduced by diffraction caused by discontinuities around the HF driver in a dual concentric format are difficult to remove entirely, the doppler modulation caused by the deep bass issue can be avoided by using a 3-way design. With all the bass information below around 330Hz being handled by the 8” bass driver, the modulation issues can be solved. While it’s true that the midrange driver will still move and potentially modulate the HF, with all being frequencies being above 330Hz the issue is effectively gone.
Returning to my earlier mysterious reference to the only other monitor being quite like the IN8 being one which costs ten times as much. The monitors to which I was referring are Genelec’s The Ones. These are, of course, very high-end monitors and I’m not suggesting that they are similar in performance but they are the only other design I’m aware of which uses this three-way approach to remove bass frequency modulation.
How Do They Sound?
However clever the design, it all counts for little if the monitors don’t sound good. How do they sound? I’ll deal with the negative first. The amps are noisy. Used at their recommended maximum listening distance of 2.8m you’re still likely to hear the noise when not passing audio. It’s not obnoxious or even distracting but it is there. If you’re asking what the catch is then this is it. That being said, as soon as you pass audio you’re not going to notice it, apart from in the quietest of pauses. If you want to study reverb tails or the effects of different dither settings then these might not be the best choice but if you’re mixing music it’s not going to be a problem.
Apart from this, it’s all embarrassingly good. As 3-way monitors in ported cabinets I ran these up against my Neumann KH310s, a much more expensive, 3-way monitor, which uses a sealed box cabinet. The bass performance is a little more extended and lacks the tightness of the characteristically dry bass of the KH310 but performance-wise it’s different but I’d be happy working with either monitor. The top-end performance is rather more different. The IN8 sounding noticeably brighter but with a slight timbral shift at the bottom of the top end around 6KHz and a little more fulness in the lower midrange, which always suggests cabinet artefacts to me, though I can’t confirm where this slight (and it is slight) congestion comes from.
It’s rare for me to still have an example of a related model I’ve already tested but in this case I still have the LP6s I tested in June and because I can, I set them up for comparison with the IN8. The results were interesting and my overriding impression was just how good the LP6 is. The mid-forward character of the LP6 I commented on in the test is even more striking when compared to the more restrained IN8. The LP6 was a little “shouty” by comparison but still made a very acceptable noise. The flatter, more extended response of the IN8 was clearly better but I have to confess they came across as a little flat compared to the attention-grabbing LP6. Mind you, we want our monitors to be flat so…
In Conclusion
All in all the IN8 is a very attractive proposition. it doesn’t have the no-brainer appeal of the LP6. Cheap is a simple message, which everyone understands. For a 3-way design, it pretty much stands alone, even seen purely as an inexpensive dual concentric design it doesn’t have much competition at this price but as both, it stands alone.
It sounds good, is eminently useable in a small to medium-sized studio and as long as some slightly noisy electronics aren’t going to be a problem for you you should definitely check them out. Whatever else is on your shortlist of 3-way monitors had better be good as they will definitely cost more than these do.
Specifications
Amp Class: D
Power Config: Tri-Amped
LF Power: 60 W
Mid-Range Power: 40 W
HF Power: 40 W
Total Power: 140 W
LF Driver: 8-Inch Poly-Coated Paper
Mid-Range Driver: 4-Inch Optimized Profile Poly-Coated Paper
HF Driver: 1-Inch Textile Dome
Freq. Response (-10 dB): 37 Hz - 25 kHz
Freq. Range (±3 dB): 45 Hz - 21 kHz
LF to Mid-Range Crossover: 330 Hz
Mid-Range to HF Crossover: 3000 Hz
Recommended Listening Distance: 1 - 2.8 Meters
Max SPL: 114 dB