Sonos Amp for Low Impedance Speakers

  • 21 February 2019
  • 2 replies
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I recently ordered a set of Focal Aria 936 speakers to run with my new Sonos Amp. Before ordering, I verified that the speakers are nominally 8 ohms. However, I now see that they actually dip to 2.8 ohms during some playback. See here -

https://www.stereophile.com/content/focal-aria-936-loudspeaker-measurements

This is slightly concerning as Sonos in other threads has stated that the Amp is only stable with 4 ohms loads. My question is will this transient 2.8 ohm dip cause issues with the Amp's protection circuit? Obviously, even a speaker which is rated at 4 ohms (and thus within Amp's approved specifications) may sometimes dip below that depending on the source material, so I hope this dip for the Focals will not be an issue.

For what its worth, I called customer service and received little guidance. They said that any dip below 4 ohms would immediately cause shutdown (which is hopefully not the case), but that any dip below 4 ohms while the speakers are not playing would be fine (which makes no sense, so I'm hoping the rep didn't fully understand the issue).

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Maybe add a high efficiency impedance matching unit to bump that up a bit?
They said that any dip below 4 ohms would immediately cause shutdown (which is hopefully not the case), but that any dip below 4 ohms while the speakers are not playing would be fine (which makes no sense, so I'm hoping the rep didn't fully understand the issue).
Lol. The second part is a silly statement so it must cast a doubt on the first part.
All speakers drop impedances when faced with music passages that demand high current to play at high sound levels; the better designed ones do not dip as low as others.
Seeing that the speakers are quite efficient with a close to 90dB sensitivity, I do not think you will have any trouble unless you play bass heavy music loud for long durations. Use the period in which returns are allowed to see if things stay ok in extended listening sessions - if they do not, change either the amp or the speaker.
The impedance matching unit will restrict current draw and consequently volume levels, so I don't suggest that as a long term solution.