• Hello and Welcome to HiFiVision.com - an online community for the home entertainment and tech enthusiasts!

    If you would like to ask a question, participate in a discussion and view attachments please Register yourself.

AVR impedance 4/6/8 ohm setting

Wharfedale Evo 4.2

spirovious

Well-Known Member
Joined
Apr 10, 2008
Messages
12,592
Points
113
Location
Mumbai
Hi,
Many new generation AV receivers has impedance selection option upto 4 ohms.
Some links say to keep it high even if manufacturer recommends.-
https://www.audioholics.com/audio-amplifier/impedance-selector-switch-1

What l observed with marantz atmos avr that when l kept 8 ohms impedance,Avr felt hot(top and sides too).
When kept 4ohm, it ran little cooler even though connected to 8ohm towers(which goes 4ohm as low).
If you ask me about sound qualittly,with 4 ohm settings, speakers sounded very well controlled and congestion free.But with 8 ohms settings ,soundstage was wider,but congested overall sound.
So what are your thoughts and findings.Which setting will be safer?
Please do share.
Cheers.
 

efernand1

Well-Known Member
Joined
Jul 6, 2012
Messages
5,513
Points
113
Location
Mumbai
For movies.....4 to 6 ohms works well.........8 ohms or more for music.....i use a SR6009 and kept all at 8 ohms (my speakers are 4-8 ohms). I am more into music and hence prefer 8ohms....
 

spirovious

Well-Known Member
Joined
Apr 10, 2008
Messages
12,592
Points
113
Location
Mumbai
When l change from 8 to 6 ohm,there is no click sound,but 6 to 4, avr make click sound.
I wonder,why avr cant auto shift impedance?
Most of the power amps support 4 ohm without need to change manually.
 

efernand1

Well-Known Member
Joined
Jul 6, 2012
Messages
5,513
Points
113
Location
Mumbai
When l change from 8 to 6 ohm,there is no click sound,but 6 to 4, avr make click sound.
I wonder,why avr cant auto shift impedance?
Most of the power amps support 4 ohm without need to change manually.

Power amps / stereo amps are built differently unlike the complex AVR which is built for specific processing etc...
 

tuff

Well-Known Member
Joined
Oct 26, 2014
Messages
2,019
Points
113
Location
Thane
I am guessing here, but i think if an AVr has options then it limits something along the lines of current so as not to send itself into clipping or shutting down. If it was built to drive 4 ohm load, i think it would not bother putting such a switch. Like "eco mode" in Yamaha receiver's.
 

spirovious

Well-Known Member
Joined
Apr 10, 2008
Messages
12,592
Points
113
Location
Mumbai
Yamaha rxv-667 had 6 and 8 ohm switch,but it could also handle 4 ohm dynamic load as per user manual.New rxv-685 can handle 2 ohm short term.
 

tuff

Well-Known Member
Joined
Oct 26, 2014
Messages
2,019
Points
113
Location
Thane
An ideal amplifier should double it's output, when dropping from 8ohms to 4 ohms and double again at 2 ohms. Receivers are never built as robust hence the desire to have separate power amps doing so. It all depends how the speaker are as far as current demand is concerned and how loud one likes to play . Safe bet is to stick with 6/8 ohm speakers if using a receiver.
Likes of Bryston are to look at or Vidar from Schiit audio. Crown XLS is also one.
 

sandeepmohan

Well-Known Member
Joined
May 17, 2009
Messages
656
Points
63
Location
Wellington
So what are your thoughts and findings.Which setting will be safer?.

The last time I had come across manually switchable impedance setting was on a old Rotel Power amplifier. Amplifier circuits detect impedance load and drive power accordingly. A bit surprised that a modern day AV receiver has such a control.

I would not switch impedance ratings other than what is specified behind the speaker, regardless to what it does to the sound. This needs to be matched.
 

spirovious

Well-Known Member
Joined
Apr 10, 2008
Messages
12,592
Points
113
Location
Mumbai
I would not switch impedance ratings other than what is specified behind the speaker, regardless to what it does to the sound. This needs to be matched.
Issue is most of 8 ohm speakers can go down 4ohm (minimum impedance).
Also found with 4 ohm setting,avr is generating less heat.Instead of switch ,it should have been automatically shift.
 

sandeepmohan

Well-Known Member
Joined
May 17, 2009
Messages
656
Points
63
Location
Wellington
Also found with 4 ohm setting,avr is generating less heat.Instead of switch ,it should have been automatically shift.

The amount of heat generated should not be the reason to choose a lower impedance setting. A certain amount of heat is expected. It is a amplifier after all. There are heat sinks to dissipate heat. Should be the least of your worries. What is more important is impedance matching. If the circuit can't auto detect and correct, then we have to.
 

tuff

Well-Known Member
Joined
Oct 26, 2014
Messages
2,019
Points
113
Location
Thane
Issue is most of 8 ohm speakers can go down 4ohm (minimum impedance).
Also found with 4 ohm setting,avr is generating less heat.Instead of switch ,it should have been automatically shift.
That means it's most likely limiting the current output. I have a Yamaha rxv477 that I used connected with Magnepan MC 1. It used to shut down if I increased volume. Replaced it with a Arcam power amplifier and haven't looked back.
 
Top