Smaller is better? I now wondered for sonics. Quantum obviously shortens its dipole radiation where IQ runs its Satori to below 600Hz. I don't know how much of that dispersion is fundamental to IQ's sound. We can't turn it off. I know that what smaller woofers give up in low-end power they often make up for in perceived speed across their upper bandwidth. Since I knee-cap IQ with a 100Hz/4th-order high pass to dovetail over to a dual 15" cardioid sub; and do likewise in the upstairs system at 60Hz with a traditional sub – I anticipated that the smaller Norex woofer might hold aces. In full-range mode I actually must stuff IQ's port with the provided bung because in my 6×8 room with open door, its bass alignment is otherwise too fat and rides the lower room mode.

I also wondered how running Mundorf's dipole AMT across more bandwidth than IQ's virtual 'super-tweeter' coverage would behave. My old Meadowlark boss had crowned a dipole AMT his favourite HF transducer for Meadowlark v2 until he discovered SB's beryllium dome. So I was well prepared to concede that Quantum won't just slip into places closed to IQ. It might possibly pack certain aural advantages. Added to costing less, could that turn tables and become the go-to Qualiofied choice? Seeing how I absolutely adore our IQ, those were heady thoughts; but for prospective shoppers very happy.

Quantum's zebra stripes sit at 4kHz/3rd-order for the AMT which adds an extra octave of coverage over the IQ's; and again 600Hz/2nd-order for the woofer. The Satori runs 2nd-order on the top and once more stays busy higher up than it would with a conventional ~2kHz filter. "As before we use all Mundorf capacitors and Jantzen inductors, with a wax coil on the midrange and an air core on the tweeter." We recognize how with our arbitrary bandwidth segregation into discrete bands, Quantum still uses a classic midrange for most the 2.5-5kHz range we call lower treble and for that tweety job rather more cone surface than a 1" dome.

With Isoacoustics Gaia footers as delivered. 

That plus an AMT's 4:1 velocity advantage promise greater-than-usual treble dynamics aka a IQ rerun. On paper then Quantum's key difference seemed to be its far narrower dipole dispersion. This had me wonder about more box talk. A dipole like the IQ's Satori doesn't see close-proximity cabinet boundaries with their inevitable internal reflections; nor the restorative force of captive air compressing like a spring. Would any of it factor in audibly suggestive ways or remain purely speculative so irrelevant? It's been my observation and confirmed by Qualio that the IQ's best performance does want a stiff solid-state amp whose superior damping adds stoppage control to the open-backed midrange. On that score Quantum might be happier with high-impedance valve amps of lower damping?

We already saw how Quantum's height with tweeter barely exceeded that of my usual MonAcoustics SuperMono Mini on its recommended Q Acoustics stand. We also saw how Quantum's width didn't exceed the stand's plinth. It's why, once in situ, Quantum looked perfectly appropriate for this smaller room. Replace the satin black paint with a veneer approximating the wooden parquet floor and these boxes would 'fade in or out' even more.

Here we see the system as I see it from the seat. A white FiiO R7 transport with 1TB SD card and touch screen is within easy reach of the chair. It dispatches USB-C to a Soundaware D300Ref USB bridge. That forwards reclocked and dejittered AES/EBU to a Sonnet Pasithea DAC with remote-controlled true variable gain. Next comes a Lifesaver Audio Gradient Box 2 smart active crossover, a Kinki Studio EX-B7 amp on the high-passed speakers, a 2 x 9½" force-cancelling Dynaudio sub on the low pass, forward placement compensating its 2.5ms DSP latency. With one remote command, the active crossover bypasses to send full-range signal to the speakers for instant from-the-seat A/B between with/out sub assist.

It's a simple but carefully curated system with special attention paid to resonance control via Hifistay and sound|kaos solutions and AC power delivery via Akiko, Furutech and LessLoss bits 'n' bobs. For today's purposes I obviously focus on Quantum in full-range mode since that's how the vast majority of prospective owners will—and should want to—use it. Actually, will want to is the operative term. That's because…