Question

Sonos Connect Amp

  • 28 December 2016
  • 3 replies
  • 398 views

I already own several Sonos products (Play 5s, 1s, and Sub) and have been very pleased with the performance. I have two sets of decent Polk Audio speakers just collecting dust in my basement. I was thinking about purchasing a connect amp to use with the speakers. The set I am most interesting in using is a pair of Polk Monitor 70 II Tower Speakers. They are rated between 20-275W. My question is if a connect amp would have enough power to get decent sound out of the speakers. I had previously used them with Pioneer Elite VSX-32 receiver with a peak of 110W per channel. Does anyone have any experience with the Connect Amp with speakers similar to this?

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3 replies

Connect Amp has a spec of 55 wpc into 8 and 110 wpc into 4 ohms. So it depends on the power draw of the Polk speakers, particularly if they draw more power via dropping their impedance to below 4 ohms at any time. If their actual impedance always stays at 4 ohms or above, Connect Amp will serve them well.
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Besides Kumar's comment about the impedance of the speaker, the other part is the sensitivity/efficiency of the speaker (dB/watt) and distance/loudness you want.

On this site they list the sensitivity of the Polk Monitor 70 Series II speakers at 90dB. Unless there's something weird going on that should mean 90dB per Watt measured at 1 meter distance. (That's the usual standard.) And that is a reasonable value for a fairly efficient speaker. BTW, it's listed as nominally 8 ohms impedance.

http://www.blu-ray.com/Polk-Audio-Monitor-70-Series-II/161287/

Over here there's a calculator for amplifier power required for target loudness (dB) values at different distances from the speaker. It's the 3rd calculator from the top. So for example, if you wanted to listen at 90dB SPL from 3 meters away, that scales to 18W, and a Connect Amp would be fine. The farther away and louder you want to hear the speakers, the more power will be required.

http://www.crownaudio.com/en/tools/calculators

Oh, and a chart like this will give you some points of reference for dB levels. 90dB is pretty loud, but some like it louder :D

http://www.gcaudio.com/resources/howtos/loudness.html
For almost all domestic purposes, based on the specs mentioned just above, the Connect Amp will do fine. Remember that it has a volume control architecture that isn't fashionable these days: at 50% on the volume slider, it delivers just approx 50% of the total power. As it should, but to give a false impression of being powerful, most modern amps deliver close to 80% power at the 50% mark on the volume control. In practice, this only means that the Connect Amp volume control may have to be set at levels that seem excessive for the required sound levels, compared to many other amps.