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Connect:AMP and 4 speakers. Safe?

  • 17 February 2018
  • 10 replies
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Hi everybody

I would like to hear about experiences from connecting 4 speakers to a Connect:AMP. Both good and bad!
I’m building a new house and are able to wire exactly as I’d like.
I would like to connect 4 B&W M-1 8-Ohm speakers to my Connect:AMP. According to Sonos this is doable, https://sonos.custhelp.com/app/answers/detail/a_id/269/kw/connect:Amp%202%20pairs%20of%20speakers?&_ga=2.142373233.2117714235.1518856759-457690909.1481985784#4_speakers , but my local hifi-pusher says it’s gonna blow the speakers with 70% certainty... I’m a little reluctant to connect 4 speakers then... Or is my hifi-pusher playing it safe or not a hifi-pusher at all :8

All replies with thanks in advance!
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Best answer by Kumar 18 February 2018, 07:48

The maximum clean power available per speaker is reduced because the power drawn by the speakers is increased by doubling the number of speakers. The amp does its best to supply this demanded power that the speakers are trying to suck out from it, and can go into clipping and/or overheating if it lacks protection circuitry, that the Connect Amp does have. The 70% is just a number, but in principle, the man is correct. Sustained clipping can destroy speakers. More speakers are damaged due to an underpowered amp that clips than from an overpowered amp that gives them all the power they try to draw from it.

The other problem is that the nominal 8 ohm spec usually does not inform of how the speaker impedance and therefore power draw changes across the sound frequency to be reproduced; there are 8 ohm speakers that stay at 8 ohms and there are 8 ohm speakers that drop impedance to 6, 4 or even 2 ohms. Four of the latter "8 Ohm" speakers may drive the Connect Amp to overload, triggering the protection circuitry.

It is however unlikely that the OP will have a problem of the amp or speakers blowing, because of how the Connect Amp is built with protection circuitry in it; if the power draw is more than what it can supply, it will shut down to protect the kit on both sides.

PS: a good idea would be install an impedance matching device between the amp and the speaker pairs. In addition to not letting the amp go into a self triggered shut down, the volume controls that are also available with these devices will allow each speaker pair to have its own volume control.
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10 replies

4 8 Ohm speakers will be fine.
Userlevel 7
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Your local hifi pusher might be a bit less of an expert that he is telling you he is.

If you double the number of speakers attached to an amplifier you roughly reduce the maximum power available to each speaker by half.

How in the world can half the power per speaker give you a 70 percent chance of blowing your speakers?
The maximum clean power available per speaker is reduced because the power drawn by the speakers is increased by doubling the number of speakers. The amp does its best to supply this demanded power that the speakers are trying to suck out from it, and can go into clipping and/or overheating if it lacks protection circuitry, that the Connect Amp does have. The 70% is just a number, but in principle, the man is correct. Sustained clipping can destroy speakers. More speakers are damaged due to an underpowered amp that clips than from an overpowered amp that gives them all the power they try to draw from it.

The other problem is that the nominal 8 ohm spec usually does not inform of how the speaker impedance and therefore power draw changes across the sound frequency to be reproduced; there are 8 ohm speakers that stay at 8 ohms and there are 8 ohm speakers that drop impedance to 6, 4 or even 2 ohms. Four of the latter "8 Ohm" speakers may drive the Connect Amp to overload, triggering the protection circuitry.

It is however unlikely that the OP will have a problem of the amp or speakers blowing, because of how the Connect Amp is built with protection circuitry in it; if the power draw is more than what it can supply, it will shut down to protect the kit on both sides.

PS: a good idea would be install an impedance matching device between the amp and the speaker pairs. In addition to not letting the amp go into a self triggered shut down, the volume controls that are also available with these devices will allow each speaker pair to have its own volume control.
I was wondering if i could connect two speaker wires to one terminal on my connect amp. i have a pair on tannoy dc2000 speakers and each of them has two terminals for LF and HF frequencies.
Userlevel 7
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If they are 8 Ohm speakers that should work fine. If 4 Ohm, probably not.
Hello guys,
I'd like to ask, if it is OK to connect a pair of 200W (maximal) outdoor speakers (the rock type) to one Connect:AMP. The speakers are TagaHarmony TRS–20 V.3 SANDSTONE - 8 ohm, 200W maximum. Will that be OK for the SONOS or would it be too much and I got to look for speakers with lower wattage?

Thank you in advance for your time!
Userlevel 7
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You don't give the most important number, the speaker's efficiency. That determines how loud an amplifier will drive them. A high number should be fine with the Connect Amp, lower efficiency and the extra power from a Sonos Amp might be a better choice.

The speaker's power rating is for the most power it can accept so the 200 watt speakers will happily accept the Connect Amp or Sonos Amp power output.
You don't give the most important number, the speaker's efficiency. That determines how loud an amplifier will drive them. A high number should be fine with the Connect Amp, lower efficiency and the extra power from a Sonos Amp might be a better choice.

The speaker's power rating is for the most power it can accept so the 200 watt speakers will happily accept the Connect Amp or Sonos Amp power output.



Hello Stanley and thank you for your quick answer. I'm copying all the information that is on the maker's site about the speaker.

Design Garden-Outdoor
2-way
Power handling 200W MAX 150W RMS
Frequency response 30Hz - 20kHz
Impedance 8ohm
Sensitivity 88dB
High-frequency driver 25 mm (1”), PEI
Bass-Midrange driver 203 mm (8”), polypropylene
Dimensions (H x W x D or Dia x D) 29 x 34 x 38 cm
Weight 5.8 kg / pc.

Sensitivity is what you were asking me about, correct? In that case it's 88dB which are about average if I'm not mistaken, right? I thought to put 4 pairs of these speakers on a Sonos Amp each, since it's more powerful than the Sonos Connect:Amp. I thought it should be ok with the Sonos Amp, but that will be available locally around end of February - start of March so I was thinking, if I have to execute the setup earlier, if Connect:Amp would be OK with the speakers too. Any help is absolutely appreciated! Thank you in advance!

Cordially,

Ivo
Userlevel 7
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At 88dB I'd think going to the Sonos Amp for the higher power would be a good idea.

Since they are 8 Ohm speakers you can only connect four (2 right, 2 left) to a Sonos Amp or Connect Amp.

At 88 dB I'd want to listen to a similar setup to see how loud it will play, even more so if you want to hook up more than 2 speakers in different areas and divide the power between them.

See here: http://myhometheater.homestead.com/splcalculator.html#anchor_13193

88 dB 55 W @10' = 101 dB
88 dB 125 W @10' = 105 dB or 108 with 4 speakers

If you need louder go with a Connect (not Amp) and add a hefty audio amplifier that will give you the sound levels and drive the number of speakers you want.
Hello again and thanks for the answer. I won't be having 4 speakers per Amp, the setup will be 4 Amp with 2 speakers each - 4 separated zones (4 small houses around a pool, but I'd like to have the option to play to all of them when needed, will be used separated mostly though or only one of them if people are in just one house at the moment - putting all 8 on one SONOS device isn't the needed solution here).
From your calculations I'd say the Amp with 105db with 2 speakers would be more than enough. I have other setups with 16 speakers and power amp + connect on another locations where it's just one house and more was needed but was used by one family.
Thanks again for all the help, it gave me the needed info to move on with the project.