When you look at the mighty IRSV and its self-amplified subwoofer system you might think it's not a great speaker to judge bass performance of the main power amp.
You would be wrong. Few systems I have owned have been so revealing of bass performance than the IRSV.
Bass performance begins well before the lowest notes of the system. The slam, impact, and transient quickness we hear are the result of the system's performance starting at about 150Hz. There, if the phase angle varies, or the signal hesitates, our perceptual hearing tells us there's something wrong in the lowest bass regions. Which is why we can tell differences in power amplifiers on full range systems augmented with powered subwoofers.
If you doubt that fact, listen to the subwoofers without the main speakers. All you'll hear are dull and sloppy thuds.
It is the amplifier driving the main speakers that provide the snap of a stand-up bass, or the kick of a drum. And the lowest notes? Those too. If the amp doesn't produce unfettered subterranean bass you'll hear that weakness in the same way.
You don't need to watch the race to predict the winner between a tortoise and hare.
It's obvious by the time they get to the starting line.
