Just to KIH it following my prior 99-part Keeping It Honest column for darko.audio, my ultimate upstairs Quantum install would run 60Hz high-passed, ports blocked. Though on paper our sealed Dynaudio subwoofer from their Pro range adds only ~10 cycles, its position in the room sidesteps a narrow-band mode. Now running Quantum sealed tightens up its lower range. High-passing the Satori adds dynamic expressiveness. Making these comments is predicated upon being set up for 2.1 stereo so owning the needed hardware. I'm not promoting it to prospective Quantum buyers. Relative to bandwidth, a sub adds precious little indeed. Integrating one seamlessly requires my extra box of outboard active precision crossover. To the previous page I'm simply adding that were I to order Quantum for our upstairs, I'd ask for a sealed version to lose the port. I'd give up about an octave's worth of reach for best time-domain integration with my preferred mains + sub setup. With that KIH'd up, let's take the show to the main floor to map how Quantum and IQ compare when everything else is exactly the same.

This signal path is very similar to upstairs, with the main difference being the 27" iMac-centric streaming front end for local and cloud files with Audirvana Studio as the signal-routing and GUI interface engine. The upstairs Soundaware USB bridge becomes a Singxer SU-6, the DAC a Cen.Grand DSDAC 1.0 Deluxe. The Lifesaver Audio Gradient Box 2 crossover is the same, the Kinki Studio EX-B7 are the mono equivalents of the upstairs stereo amp. Because the 2 x 15" cardioid sound|kaos sub is passive, here a pair of Gold Note PA-10 Evo bridged to mono handle sub 100Hz bass amplification. As it turned out, my upstairs prognostications about Quantum/IQ offsets were spot-on.

Whilst staging no smaller per se—no sorting coordinates shifted—Quantum didn't pack IQ's special 'it' factor which Anglicized French calls ne sais quoi. It's a certain hard-to-express quality which is nonetheless most real. I shall call it the tacitness of audible space. Think of how a really hot very dry summer's day can render air visible when it begins to flicker off boiling tarmac. Subtract the flickering et voilà: awareness of air/space as an ever-present substance that's all around/between the images. That was the primary distinction whose enabler just had to be IQ's far wider dipole dispersion. It had two side effects. One, IQ's dynamic scaling was grander. It literally moved more air even if half of it aims backward rather than stuffs into a box. Two, if you can cancel all porno/political subtext, IQ played it more deep throat. On big vocals doing big things, IQ projected more full-throttle gush. By contrast, Quantum's throat and vocal chords didn't seem as relaxed or wide open. This too I attributed to box-less open-backed driver un-loading versus box loading. Because for these sessions I ran Quantum high-passed exactly as IQ to eliminate all sub-100Hz room shifts, this really was the extent of difference. I'll just add that another aspect of the dipole/box bandwidth changes had Quantum's general gestalt slightly darker than IQ's greater top-down energization.

In high-passed mode, I stuffed Quantum's port with a pair of tightly 'screwed in' wool socks.

For a suitably large room, the upshot is crystal. If you already listen to IQ, you've bagged Qualio's whale. Leave it alone. If your room is smaller, you could very well come down to a sudden death vs. eternal life decision. Be it for cosmetic, sonic or both reasons, wherever IQ is overkill—too imposing of width, too bassy of response—Quantum slips right in. If you don't rate IQ's spatial I-don't-know-what wrinkle as its primary attraction, Quantum gets you there nearly all the way. If you rate Quantum's slightly darker demeanour higher, you could well prefer it. Just remember the basic 'soundstaging = setup' equation. If you want superlative depth layering, learn from how the pros at Boenicke, Børresen & Raidho set up at shows. Wall hugging is not in that picture. It's why my layouts account for necessary front-wall clearance. Depth isn't built into a speaker. It's created by our setup. And yes, crossover phase shift and cabinet flex certainly influence general soundstage focus and clarity but the primary liberator or prison warden of soundstaging is 'free-space' clearance or lack thereof. It's super basic.