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post #1 of 9 Old 09-16-2019, 03:50 PM - Thread Starter
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2 channel dumb question..

Take for example the Hardan Karmon 3770 or the Onkyo TX-8270. They are both 2 channel receivers but have 4 speaker outputs. Two speakers for the left and two for the right. If this is 100W RMS per channel, are the two speakers on the left sharing that 100W, and the two speakers on the right sharing a 100W, as well, resulting in only 50WRMS going to each of the 4 speakers? If so, it would send more power if I only used two speakers? Thanks!
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post #2 of 9 Old 09-16-2019, 04:04 PM
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There are only 2 amp channels, so if you connect four speakers to either one of those receivers you better make sure they are at least 8 ohm speakers. Connecting four 4 ohm speakers may cause harm to the receiver. There should be a caution note on the back of the receiver not to exceed the 8 ohm limit. If you have 4 ohm speakers then you can only use one set of speaker connections, i.e. two speakers. Since the amps deliver up to 100wpc you can't get more out of them than 100wpc.

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post #3 of 9 Old 09-16-2019, 05:37 PM
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Originally Posted by Knucklehead90 View Post
There are only 2 amp channels, so if you connect four speakers to either one of those receivers you better make sure they are at least 8 ohm speakers. Connecting four 4 ohm speakers may cause harm to the receiver. There should be a caution note on the back of the receiver not to exceed the 8 ohm limit. If you have 4 ohm speakers then you can only use one set of speaker connections, i.e. two speakers. Since the amps deliver up to 100wpc you can't get more out of them than 100wpc.
There is definitely one of those warnings on the back of the 8270:

It's a great receiver though, punches way above its price IMO.

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post #4 of 9 Old 09-17-2019, 02:35 PM - Thread Starter
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They are 8ohm speakers. I have 4 Technics SB-L95s. The Onkyo has 2 positive and 2 negative outputs for each the left and right channel for a total of 4 speakers that can be hooked up. For right now, lets just talk about the left side. If the left channel is 100watts RMS and I connect only one speaker, it gets 100RMS. But if I connect two speakers to the left are they both getting 100W or do they share the left channels 100W meaning they both are only getting 50W RMS on the left side. Or an easier way to ask this is... are ALL four outputs sending 100W to each of the 4 speakers? Didnt know if Im going to here a loss in volume/power by connecting all four speakers because it seemed like I did when I had an old Technics receiver.
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post #5 of 9 Old 09-17-2019, 02:51 PM
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Originally Posted by shawntmartin View Post
Take for example the Hardan Karmon 3770 or the Onkyo TX-8270. They are both 2 channel receivers but have 4 speaker outputs. Two speakers for the left and two for the right. If this is 100W RMS per channel, are the two speakers on the left sharing that 100W, and the two speakers on the right sharing a 100W, as well, resulting in only 50WRMS going to each of the 4 speakers? If so, it would send more power if I only used two speakers? Thanks!
I just looked at the specs for the harman kardon 3770 and it says 120w per channel, two channels driven @ 6-8ohms. So I would think it would be lower if you add another pair of speakers. I don't think it would be a 50/50 split though. Most receivers the power is diminished when you add more speakers unless you are dealing with higher end equipment. For example, NAD typically has a rating that says all channels driven.

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post #6 of 9 Old 09-17-2019, 02:56 PM - Thread Starter
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Gotcha. I was just wondering if it was a noticeable decrease then I would just sell two speakers and use that money for an extra floor sub since the Onkyo has 2 sub outputs.
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post #7 of 9 Old 09-19-2019, 04:41 PM
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Originally Posted by shawntmartin View Post
Gotcha. I was just wondering if it was a noticeable decrease then I would just sell two speakers and use that money for an extra floor sub since the Onkyo has 2 sub outputs.
Excellent idea.

It's a VIRTUAL channel unless stated otherwise.
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post #8 of 9 Old 10-02-2019, 11:14 PM
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I currently own the HK 3770. Your question isn't a dumb one. The answer is simple though- When using 1 left and right spkr (A or 1), you get 120 watts to each spkr. When you connect another left and right, (B or 2), and play them all at once, you will definitely notice a drop in volume from each spkr. It may not be a 50/50 split, but it's definitely noticeable.
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post #9 of 9 Old 10-21-2019, 09:15 AM
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Think of this in terms of Voltage and Current. Inside the amp, Speaker-A and Speaker-B are the same point. So, the Amp applies voltage as set by the signal and the Volume Control. The same Voltage is applied to both speakers. How much Current flows is based on the Impedance of each speaker.

Power = Voltage x Current


Amp Power Supplies have limits on how much current they can possible put out. So, that is the limiting factor. Also keep in mind that the more Current that flows, the hotter the amp gets.

Most amp are limited to total loads of 4 ohms to 16 ohms per channel. Two 8 ohms speakers connected in a standard configuration, equal 4 ohms. So that is pretty much the limit.

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