August 4th. Apparently separate group feedback had elicited more animosity about color-coded status indicators since one of its members is actually colorblind. Very good-naturedly, Pál took it all in stride and adapted. "After the Technicolor fiasco I decided to give our customers a luxury IMAX experience for their optical feedback. This makes the small LCD display obsolete so I won't waste time on writing code for it. In exchange you'll get this big gorgeous 3-digit white LCD display which will connect via 6-way ribbon to the controller board."

The GB2 project was nearing the final straights, checkered flags in sight. Having now three digits to work with, Pál quickly came up with intuitive abbreviations for the core settings: H_L [normal xover mode of HP+LP], 2HP [stereo high pass only], LHP [left high pass only], RHP [right high pass only], 2LP [stereo low pass only], LLP [left low pass only], RLP [right low pass only], PH0 [0° sub phase], PH1 [180° sub phase], 6db [boost], A__ [A side filter settings], __B [B side filter settings]. "No need for longer ticker-tape text. The larger white digits offer very good legibility even across 5-6 meters. Of course during normal listening the display will go blank and only reawaken during adjustments like phase, boost and mute over the gorgeous black remote. With the bespoke laser engraving, that will be unique. It'll also be an option for the higher-end icOn versions to upgrade the small Apple wand. Once THE icOn bows, it'll have its own desktop remote with built-in 960×540 4.7" e-paper display with 16 gray levels, separate encoders for high speed, fine adjustment and other smart features. For GB2, the dot between the 2nd and 3rd digit will be the 'on' indicator. In the forthcoming icOn 5, that becomes the decimal point for the new 0.5dB attenuation steps."

In early September, I learnt of another maker working on a sub xover. "The sum of its outputs always gives a flat response pure in phase. So 2nd, 3rd or 4th-order slopes are all possible. If for example you feed my filter a square wave on top of the crossover frequency, the sum of the outputs will always be a square wave. To your question whether such a filter could be variable, the answer is yes. However, the more orders, the more variable resistors we need. For example if we use a 4th-order approach, we need eight variable resistors. The disadvantage I find here is that we must then meet our goal with digital potentiometers or four ladder DACs. To keep it simple and discrete, I would like to go for a fixed 4th-order filter at 80Hz or use modular resistor boards for a specific frequency." This reiterates why the GB2's flexibility is rare. What had Pál in store for his first tradeshow in the UK?

"In October I'll introduce four new products but unfortunately not yet the new THE icON with nanocrystal-core 'variable' Finemet autoformer for something like a tilt control with remote but no passive or active additions in the signal path. That needs much more R&D because everything will differ from the current 4Pro platform. Hopefully I can show it in Bristol next February. This October I'll show something unique for high-end loudspeakers with DSP crossovers – an 8-channel 4Pro with four pairs of autoformers together with my own Linkwitz LX521 4-ways with analogue active and DSP crossover and a dozen of my own acoustic panels for room treatment. icOn 5 will bow with its 168 x 0.5dB steps, a beautiful white display and 8 pairs of RCA sockets; the icOn 4 Zen with 48 steps, same Slagleformer but no optical encoder or CNC'd faceplate for half the price of a 4Pro in limited quantities and for a limited time; and the latest Gradient Box with remote-controlled volume and balance between sub and mains. I'm now waiting for the new PCB for that."

By September 5th, I'd asked Martin Gateley for his experience with the GB2. "I really like what I hear. Integration of mains/sub is seamless. On my Vox monitors I settled on a 100Hz low pass and 90Hz high pass. The 10Hz overlap gives me slightly smoother integration. I had one dealer recently mention that for him too the 3A has a minor suck-out in the upper bass which would correlate. Both 90/90 and 100/100 work well but I suspect this is very space related. In my room it's similar for the Libération where I prefer a 70LP/60HP setting. 40/40 also works but integration isn't as good and 60/40 gets too heavy. I was surprised by how much 10Hz can affect the room at these lower frequencies." This was lovely feedback for the utility of asymmetrical settings I'd never yet tried.

By September 23rd, "GB 2.5 isn't too far from a working prototype. My latest idea to handle the very different setup process and daily usage is an enclosure flip-flop. For setup the switches really should be in the top position but for normal listening, it's better if they're at the bottom. A small tilt switch will read the position of the box and rotate the display 180° as needed. The final enclosure will be 220mm long and due to the XLR sockets, height will mirror that of the balanced icOn 4Pro and 5."

… to be continued when this project completes…