Frequently Asked Questions
What type of DAC does the system use?
The system is optimized for digital sources and the analog stage is part of the DSP hardware. The standard DSP device uses an AKM AK4440 multichannel DAC chipset, with 24-bit, 96 kHz resolution. There are eight analog outputs on RCA plugs with 2v RMS output level.
What is the sensitivity of the speakers?
There’s not a simple answer to this question, when speaking of an active system. Sensitivity varies quite a bit across the sound spectrum, but the digital processing compensates by reducing output voltage where sensitivity is higher and boosting voltage where sensitivity is lower.
The important thing is to use an appropriate size amplifier. We use an amp with a rated 125 watts into 8 ohms, 190 watts into 4 ohms. This has proven to work very well.
Is the amplification built into the speakers?
No, the amp and DSP are both outboard. You can locate them together with source components in an equipment rack. Six amp channels are needed, and we use a 7-channel home theater amplifier for demo setups. 50-200 watts per channel recommended.
How is the system hooked up?
Hookup is different from a typical passive speaker system. First you need six interconnect cables between the amp and the DSP unit. A preamp can control source selection and go ahead of the DSP if desired. Or simply connect a digital source directly to the DSP. Using an audio/video receiver is possible, but the built-in amplification would not be usable with the IAQ speakers.
There is also a special type of speaker cable needed to connect the speakers to the amplifier. Custom speaker cables are included with the system.
Analog sources would require a preamp that can output a digital signal to the DSP. Please contact us for guidance.
Can you explain the unique shape?
Believe it or not, this is a form-follows-function design. Design process begins with assumptions, concepts, ideas and sketches, then moves onto prototypes and testing, followed by redesign. Features that don’t work get revised, and features that are needed get added. Whatever works can stay for the next generation.
One unsuccessful prototype several years ago led to a major breakthrough. At the time, the speaker design was relatively wide, and had a rectangular shape as seen from the front. Along the sides there were sidewalls that angled back. The sidewalls added strength, and enough depth to allow a grille to cover the drivers at the back. The last version in this series of prototypes was wider than the previous, and was the first to include a rear facing tweeter.
What stood out was how bad it sounded from the back, and how it had less dipole magic from the front, compared to narrower baffles tested earlier. People sometimes say that the major benefit of a dipole is avoiding box coloration, because you always hear the box. But another truth less well known is that with a dipole, you always hear the back. An ideal dipole needs to sound nearly the same from the back.
The breakthrough that resulted was to separate the cabinet into a larger lower cabinet for bass, plus a smaller top module for the midrange and tweeter. The top baffle ended up just 1″ thick, with a minimum of material separating the front and back sides of the sound. Where wavelengths are shorter, the speaker is smaller, ideally not more than a wavelength wide. This is the core principal for a minimalist open baffle design. The ultimate dipole speaker gets out of the way of the sound, and achieves greater transparency than any other type of speaker design.
Several generations followed before the IAQ found its iconic sculptural shape. Originally the lower cabinet was very boxy. Measuring the polar response with a turntable (rotating the speaker to measure the sound at different angles) revealed comb filtering from reflections off the lower cabinet. This affected the midrange frequencies. The solution was to rotate the woofer cabinet 45°, making shoulders that slope down away from the top baffle.
That led to the trans-lam construction, which makes this geometry possible. Wide bevels slice away material to streamline the cabinet, again to minimize upper frequencies reflecting off the lower cabinet.
Lastly, the shape evolved further while drafting shop drawings for CNC machining. CNC is needed to cut parts from panels of raw material. Each part got a series of tweaks until all the parts nested closely together, making efficient use of material and machine time.
And of course, no design is ever truly “final”.
What are the crossover frequencies?
Without a subwoofer the system is 3-way, crossing at 300 Hz and 2.1 kHz. With a subwoofer the system is 4-way, crossing at 50 Hz, 300 Hz and 2.1 kHz.
The DSP controller has presets for switching a subwoofer in or out, so when you want the subwoofer the speakers go down to 50 Hz while the sub takes over below that. Even with a sub connected, you can run the speakers full range by choosing a preset that mutes the sub and runs the speakers down to 20 Hz.