How bad are low impedence surround speakers for Denon 3802? (1 Viewer)

[Frank Chang]

I'm replacing a 10 year old surround AVR. Just ordered a Denon 3802. I was reading downloaded manual and it says impedence of surround speakers should be greater than 6 ohms. My 4 surround speakers (2 rear & 2 side) are 15 year old Canton Plus 4 ohm custom installed into the house.

The Denon manual stated that using lower impedence speakers (< 6 ohms) would cause damage and activate the protection circuit, if the speakers were played to loud too long. It did not specify if the amps or the speakers would be damaged, or what defined too loud for too long.

I doubt that I would play them too long or too loud. Could I add a 2-4 ohm resistor in series with each of the speaker leads (one per speaker) to increase the overall resistance seen by the amps, or should I just go for it and not worry. My previous surround AVR did not specify and has been running these speakers for over 10 years with no apparent problems.

Please respond if you have ideas, experience, or technical knowledge.

 

[Kyle_Y]

Not to worry. If you go to Denon's website, and go to the FAQ's, then it addresses the point of using 4ohm speakers. 4ohm speakers are not a problem for the Denon receivers, they will be able to handle them fine says Denon. I also have 4ohm speakers for my front speakers so I was concerned, but I will be buying a Denon receiver too.

 

[Frank Chang]

Thanks. Would there be an advantage to adding some more impedence to each speaker? The other issue is the max rating for the speakers is 70 watts and the 3802 puts out 110 watts into 8 ohms and alot more into 4 ohms. There is potential to fry the speakers if someone (ie. teenage kids) turns the volume up too high. Looks like you can adjust the gain to each speaker individually in the set up but that must be to match all 7 speakers to each other.

 

[Kwang Suh]

The other issue is the max rating for the speakers is 70 watts and the 3802 puts out 110 watts into 8 ohms and alot more into 4 ohms. There is potential to fry the speakers if someone (ie. teenage kids) turns the volume up too high.

Nope. Having your receiver have more power than your speakers need is actually a good thing, as it means that it's going to be very, very hard for the receiver to send a clipped signal to your speakers, which is the source of speaker problems. Also, 70 watts is extremely, extremely loud. Like, so loud that even your kids will have their ears bleeding with prolonged exposure.

 

[Carson E]

Frank...Remember the 110 watts mean nothing in a multi-channel mode.

A recent HT mag reviewed the 3801 and when in 5 or 6 channel mode the power rating dropped to something like 60 watts per channel. It would be nice if manufactures would rate their output with all channels driven.

I would think you would be fine.

Enjoy the 3802.

 

[Bryan Acevedo]

Carson - actually with 6 channels driven it was 85W, 5 channels driven it was 92W. I don't know where you got the 60W, but that is not true. And, in fact, Denon never claimed that the 3801 could produce 105W with all 7 channels driven - only people on this forum claim that for them. What they say, is that each channel is capable of 105 W, which is actually underrating them, since in the same test, one channel was capable of 140W before clipping. And in stereo mode, they got out 120W.

I wouldn't worry about the 4 ohm speakers, especially since they are surrounds. Surround speakers only get bursts of sound during a movie, so it would be extremely hard to actually overdrive a receiver during a movie based on the surround speakers. If you use 7 CH stereo, that may put a load on it, but only if you have it cranked extremely loud, for hours at a time. And if you have your speakers set to small (which I would recommend), the hardest part of the load (the part that actually dips to 2 ohms) will not be there, since it is the lower bass frequencies that require all the current. A tweeter no matter what it is rated at, just doesn't ever pull more than a few watts. If it did, you would have windows breaking! It is the woofers that pull all that power from the amps.

Bryan

 

[Frank Chang]

Thanks!

Why do you think they warn in the manual to use surround speakers greater than 6 ohms?

 

[Kwang Suh]

It's a warning. They're covering their asses.