Designer Russell Kaufmann describes the £5,950 Red 120Se as like a BMW M3/M5 variant of the standard Red 120 (£3,950). Above the Red 120 in the range is the £5,250 Red 150 and the Se variant of that is priced at £7,450. Below those are the Red 100 and Red 50 (£2,450 and £1,850).
If you don’t know Russell K, it’s a British company, founded in 2014 by Russell Kaufmann, who has been involved in the hi-fi industry for many years, starting out working in retail at KJ Leisuresound in London’s Wigmore Street and then moving on to work for such prestigious companies as B&W, Wharfedale, Monitor Audio and Morel.
Kaufmann tells me that this experience gave him an insight into what to do in terms of loudspeaker design, but also what not to do and during his time at KJ he got to listen to many prototype speakers manufacturers would bring in for assessment.
Kaufmann has his own thinking on loudspeaker design and there are some interesting facets to the design of the Red 120Se worth dwelling on.
In terms of what extra you get over the five-yearold Red 120, the woofers remain the same, but the Se gets a new tweeter: it retains the same soft dome but has an extra magnet and a metal faceplate instead of the original plastic one, which is said to provide more information and perform better on complex source material. The crossover has also been adjusted slightly to a lower 1.8kHz to better match the revised tweeter.
Kaufmann tells me that he firmly believes in a simple crossover, and his philosophy is to have only one component, and no resistors, in the signal path. The other components in the network go to ground. The one 3.3uF capacitor in the signal path has another one tenth its value in parallel, which Kaufmann says lowers the crossover frequency while enabling the crossover to have a faster rise time because of its smaller value.
Kaufmann also shies away from using air-cored or ferrite-cored inductors in his crossovers, believing >

> that the downside of air cores is that they need more turns of wire and as such have much higher DC resistance (DCR), which he says ‘wrecks’ the damping
factor of an amplifier.
He also feels ferrite cores saturate and distort very quickly and, worse still, ‘act like a radio transmitter’, pushing an ‘astronomical’ amount of energy back into the other components in the crossover. His answer is to use Enclosed Field Iron Core Inductors, which he tells me have very low DCR, high power handling and don’t pollute the crossover with radiated energy.
In the Red 120Se, he uses two of them, one in the positive signal path and a second in the negative return path. He says this creates a balanced circuit and although there are no measured benefits, he has noticed an improvement in “bass tunefulness”.

Internal baffles

As for the cabinets, these are 16mm MDF with a 19mm front baffle, and three internal baffles dividing the cabinet, with multiple holes drilled in them.
These baffles, says Kaufmann, minimise the effects of ‘wavelengths’ travelling the length of the cabinet.
There’s also a second internal reflex port, responsible for the main tuning of the system. The output vents into a small cavity and exits through the external port. This is said to enable the much longer port needed to tune to 21Hz without the effects of port resonances, as they are lost within the lower cavity.
Internally, the cabinets are not lined with foam or stuffed with BAF wadding, as Kaufmann has found such damping tends to store energy and results in the speaker sounding more constrained. He realised that removing it could result in the cabinet ‘sounding like a wardrobe’, but those internal braces, he says, help solve that problem. Another interesting aspect of his design philosophy is that, after considering any technical parameters that may be relevant, he always listens his tweeter and woofers individually, outside the >>>

>>> box, on a full-range signal. He has rejected many drive units on the basis of how they sound during this test. He demonstrated the technique to me and I must admit it was most interesting. He says that this prevents him from ending up with a flawed drive unit that then needs to have those flaws corrected with a needlessly complex crossover. So he prefers to listen to the drivers first, choose the best-sounding, and then keep the crossover simple.
So much for the technicalities – would the Red 120Se live up to the promise it showed at the Daventry show?
To put them to the test, I hooked them up to a system consisting of an Audio Note Cobra integrated amplifier (25W push-pull pentode), with the music provided by that company’s TT3 turntable with Arm2/Io1 cartridge through an S9 transformer
into an M2 RIAA phono stage, supplemented by a CD5.1x CD player.
In my room, I have the luxury of a solid brick rear wall and corners for the speakers. After moving them around, further away from and nearer the walls, I ended up with the best sound and balance with them 28cm from the rear wall and 35cm from the side walls, slightly toed in. The plinths are provided with substantial locking spikes and so giving them with a solid footing was not difficult, and for those who need help, Russell K provides a very useful set-up guide.

Weighty, yet tuneful

The first track I tried was guitarist Peter White’s superb version of ‘I Can See Clearly Now’ from his brilliant Groovin’ CD. Here, the Red 120Se speakers conveyed his guitar with great articulacy, bite and presence, revealing the subtleties and mastery of his technique. Percussion was detailed and delicate and the bass line that really gives the track its lilting rhythm was well captured – weighty, yet tuneful.
Onto the TT3 went the Build Me Up from Bones LP from Sarah Jarosz. Playing the title track, the Red 120Se gave her vocals great expressiveness, emotion and naturalness with every push and breath nicely handled without any undue harshness, while subtle detail on her mandolin and the violin and cello backing was beautifully and coherently presented. Everything was nicely balanced, detailed and tuneful.
Next LP up was Bop City from Ben Sidran. On ‘It Didn’t All Come True’, Sidran’s vocals were open, articulate and full of emotion and nuance, and when he hit a piano note hard, you could hear it, with the drumkit also conveyed with excellent dynamics and impact, and without any splashiness or harshness. In particular, Eddie Gomez’s bass line also really moved, underpinning the impetus of the entire track. >>

>> Then on to Saxophonic, from one of my favourite sax players, Dave Koz. On Honey Dipped, Koz’s sax had great presence, body and intelligibility without being harsh or overbearing, with Rick Braun’s trumpet also nicely separated in the mix. Percussion from Lenny Castro was handled with all due dynamics and delicacy and the rhythmic ebb and flow and impetus of this funky track was handled with aplomb by the Red 120Se. It made me want to get up and dance!
Let’s finish with one of my favourite Bruce Springsteen tracks, ‘Racing in the Streets’ from his Darkness on the Edge of Town LP – a brooding, moody song packed with emotion. On the Red 120Se, his voice was open, clean and packed with emotion. The piano had great body and dynamics and the drumkit, too, had power and yet great detail and finesse – and when that great, powerful bass line joined in, you really felt its power and weight.

An excellent performance.

The Red 120Se is my first acquaintance with a Russell K speaker but I’ll be keeping my eye on the brand in the future. The Red 120Se was detailed, clean, well balanced, tuneful and able to convey the subtleties in vocals and how instruments are played, and the rhythmic twists and turns, that are the essence of the musical experience.