Sinks Connect Amp & In wall volume controls

  • 11 August 2018
  • 6 replies
  • 1620 views

I have 1 Sonos connect amp, 6 in ceiling speakers, and 3 osd vms100 in Wall volume controls (controlling 2 speakers in each room)(https://www.outdoorspeakerdepot.com/vmimmaslvoco.html).

Is this set up ok? I have yet to connect it all together. I do not want more than 1 Sonos as I specifically want same source in all 3 rooms. Thanks!

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6 replies

Sonos doesn't recommend connecting more than 2 pair of speakers directly to a connect:amp. I would think about adding a speaker selector to that setup to help with impendence matching and to make the wiring a little easier.

And honestly, you may find the connect:amp doesn't quite have enough power to drive all 6 speakers. For backgroud music and light listening, probably fine. Otherwise, you may want to look into getting a Connect + a more powerful 3rd party amp.
In wall volume controls have the impedance matching feature....that’s why I’m wondering if it would work the way it is now.
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As long as the final system appears to be more than 4 Ohms to the Sonos Connect Amp it will work.

The description you linked to is really weak but it looks like they would do the job. Going by the 5th picture they look to be transformer based which is good and saves more power for making sound than resistor based ones.

Impedance matching for 2, 4 or 8 pairs of speakers and can be used as non-impedance matching if leaving default on jumper setting at 1X.


The chart a few pages in here is much better.

https://sep.yimg.com/ty/cdn/yhst-5323690727015/volume-control-quick-tips.pdf?t=1533860922&
If the speakers are 8 Ohms you can use the 2x setting. 4 Ohm speakers should use the 4x setting.
Isn’t it 4x for 8 ohms since I’m connecting 3 pairs of speakers ??
The "1x" setting passes the speaker's actual impedance through to the amplifier. Two sets of 8-Ohm speakers will present a 4-Ohm load to the amplifier when connected directly to the amplifier. CONNECT:AMP will directly support this without any controls. If a control is used for both sets of 8-Ohm speakers, in "2x" mode the impedance presented to the amplifier will be 8-Ohms. For three sets of speakers the calculation is a bit more complicated. "2x" converts each pair to 16-Ohms. Three 16-Ohm speakers in parallel results in a 5.33-Ohm load presented to the amplifier. This is fine for CONNECT:AMP.

It would not be wrong to use "4x" in your installation, but this will limit the maximum volume somewhat.

Note that speaker impedance varies with frequency. That "8-Ohm" spec is really a value judgement by someone. Some speakers are notorious for having a low point, usually at a bass frequency, that is much lower than the spec. In this case a seemingly docile 8-Ohm spec'd speaker might turn into a 2-Ohm monster for a certain bass note. And, unfortunately, some 8-Ohm speakers would be more honestly spec'd at 6-Ohms.

My recommendation is to start with the "2x" setting. CONNECT:AMP is a hard to damage, robust unit -- it can take care of itself. If CONNECT:AMP shuts down after a loud bass note, use "4x".

There is no hard rule relating goodness of sound with a speaker's impedance spec.