4ohms Axiom Driven by an Onkyo?

[klix58]

May be a silly question as I have read articles here on impedance but here goes, I have an Onkyo TXNR-905 which is currently driving Klipsch 8 ohm speakers, I am ready to go with the Axiom M80 and as they are rated at 4 ohms as opposed to the Klipsh? Any concerns I should have? Thanks to any reply.

 

[MinusTheBear]

This is what someone posted on a Axiom Audio Message Board:

As I've explained in previous posts, the AV receiver brands that Axiom has found able to drive the 4-ohm M80s without severe current limiting or shut-down are: Sherwood Newcastle (which we have bench-tested and which Axiom sells on-line); Denon, Harman/Kardon, B&K, Rotel, NAD, and McIntosh.

The AV receiver brands to avoid if you want to get the 4-ohm M80s are: Sony, Kenwood, Onkyo, JVC, and Yamaha (except for one or two models).

p.s. to my previous post: In my list of recommended AV receiver brands that will drive the M80s, I forgot to include Outlaw Audio.



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The quote above was from Alan Lofft from the following thread. Sorry no specific models but theses are at least the recommended and not recommended brands. For specific models it mostly depends on what features you want.


Personally if i had the cash i would match the M80's with a Emotiva Pre Processor and Emotiva Amplifier....

 

[satish536]

I believe the TX-NR905 is one of onkyos top end amplifier, i think it would be able to handle the load.

Later on down the line, if you feel your not satisfied with the sound, or you have shutdown issues etc, you can always get an Emotiva Amp and try it out with your speakers.

 

[j_garcia]

If it is only those two and you have a decent sub thereby allowing you to run the 80s with any kind of crossover, you shouldn't have any problems. If all of your speakers were 4 Ohm, I might worry, but just one pair shouldn't cause an issue.

 

[klix58]

So far thanks to the replies, I have also visited the Axiom Forums and no one has yet posted on this recieveronly lesser models.

 

[Davemcc]

The TX-NR905 is rated into 4 ohms and has a torroidal power supply. In fact, Onkyo gives a "dynamic" rating down to 3 ohms. It will be fine with the Axioms.

 

[hifihawaii]

4 ohm Axioms

Not many receivers rated for 4 ohm speakers. If you are going to play loud for extended periods of time, try a Rotel. Have Dynaudio Focus floorstanders and center with Magnapan wall mounted surrounds. HK AVR 635 would overheat after about 6 - 8 hours. Pretty good sound. HK engineer recommended using pre-amp outs and a power amplifier.

Then tried an Arcam AVR 300. Oh so sweet sound but this one overheated after about 6 hours. Dealer lent me a Rotel 1056 Receiver until I could find something I liked. This one pounded effortlessly for over 24 hours straight. Unit is pretty much hot to the touch after 5 minutes but never overheated. Good functionality, good sound. Ended up keeping the Rotel but added a Sunfire Theatre Grand 7 x 200 watt power amp.

Pretty sharp guy at Magnolia wouldn't even recommend his top of the line Denon or Pioneer Elite receivers for 4 ohm speakers.

 

[klix58]

Thanks Davemcc, when I speak to the knuckleheads at Onkyo all they do is reference the manual (as though I didn't get one, or have the ability to read)and recomend min. of 6 ohms. The web site shows the dynamic power though. Also I have read leave the setting in the reciever at 8 ohms and go or do you feel the 6 ohm setting may be better (safer)? I am still trying to get a grip on this. Thanks

 

[Davemcc]

On the website's spec page, the last entry also lists speaker impedance as 4-16 ohms. The ability to drive a 4 ohm load is a function of the amps ability to deliver enough current to the speakers. The power supply in the 905 should be easily capable of delivering enough current. Rotel only rates their receivers into 8 ohms, and even some of their separate amps. Rotel has a separate line of high current separate amps for driving low impedance loads.

Conventional wisdom on this site is to leave any impedance settings at 8 ohms, regardless of speaker impedance. The switch is only there for ratings purposes during testing.

 

[Seth=L]

One of the requirements for THX Ultra II is that the amplifier be able to drive loads of 4 ohms and slightly below. It would not have passed that certification if it wasn't capable of handling a 4 ohm load. The TX-NR905 should handle the load with no problems at all. Disregard the generalizations by the manufacturers. Trust in the certification (which is tough to get) and the tests that prove it. The TX-SR875 was able to drive 4 ohm loads with no problems as shown benchtests, the TX-NR905 should have an advantage over the TX-SR875.

 

[klix58]

You people are the Best! I have learned more and hence enjoyed more in reading here again Thanks.

 

[cerwinmad]

You people are the Best! I have learned more and hence enjoyed more in reading here again Thanks.

Hi, i have an Onkyo TX-SR503 and it states in the manual that the american version is suitable for speakers 6 ohms and higher, and all other versions (ie europe) are suitable for use with speakers between 4 ohms and 16 ohms. it doesnt say you cant use 4 ohm speakers, but warns after long durations it may get hot and thermal cut out until cool enough (american model). my unit has a setting that lets you choose between 4 ohm and 6 ohm. i live in New Zealand so presume i dont have american model!! lol

 

[3db]

Not many receivers rated for 4 ohm speakers. If you are going to play loud for extended periods of time, try a Rotel. Have Dynaudio Focus floorstanders and center with Magnapan wall mounted surrounds. HK AVR 635 would overheat after about 6 - 8 hours. Pretty good sound. HK engineer recommended using pre-amp outs and a power amplifier.

Then tried an Arcam AVR 300. Oh so sweet sound but this one overheated after about 6 hours. Dealer lent me a Rotel 1056 Receiver until I could find something I liked. This one pounded effortlessly for over 24 hours straight. Unit is pretty much hot to the touch after 5 minutes but never overheated. Good functionality, good sound. Ended up keeping the Rotel but added a Sunfire Theatre Grand 7 x 200 watt power amp.

Pretty sharp guy at Magnolia wouldn't even recommend his top of the line Denon or Pioneer Elite receivers for 4 ohm speakers.

accoring to Rotel, they don't recommend using 4 ohm speakers either. The tried and true NADs are 4ohm stable and even spec down to 2 ohms.

 

[Seth=L]

Hi, i have an Onkyo TX-SR503 and it states in the manual that the american version is suitable for speakers 6 ohms and higher, and all other versions (ie europe) are suitable for use with speakers between 4 ohms and 16 ohms. it doesnt say you cant use 4 ohm speakers, but warns after long durations it may get hot and thermal cut out until cool enough (american model). my unit has a setting that lets you choose between 4 ohm and 6 ohm. i live in New Zealand so presume i dont have american model!! lol

If you switch an Onkyo receiver to the 4 ohm position it actually limits it's output current. They do this to protect the receiver from getting to hot under a difficult load. The TX-SR805 and up are meant to drive 4 ohm load speakers.

 

[Joe Schmoe]

All of the Onkyo receivers I have seen are high-current and rated to drive 4 Ohm loads. This includes even their cheapest, entry-level models.

 

[Davemcc]

All of the Onkyo receivers I have seen are high-current and rated to drive 4 Ohm loads. This includes even their cheapest, entry-level models.

Not so. Look at the last line of the Amplifier Section specs of the TX-SR605, speaker impedance. It clearly shows the 605 is only rated from 6-16 ohms.

http://www.onkyousa.com/model.cfm?m=TX-SR605&class=Receiver&p=s

 

[Seth=L]

All of the Onkyo receivers I have seen are high-current and rated to drive 4 Ohm loads. This includes even their cheapest, entry-level models.

Ignore those peak ratings into 3 ohms, they mean nothing.

 

[Davemcc]

Ignore those peak ratings into 3 ohms, they mean nothing.

I guess it might be handy to show that the receiver could handle short frequency related impedance swings, but yeah, dynamic power is pretty much a useless spec.

 

[cerwinmad]

Not so. Look at the last line of the Amplifier Section specs of the TX-SR605, speaker impedance. It clearly shows the 605 is only rated from 6-16 ohms.

http://www.onkyousa.com/model.cfm?m=TX-SR605&class=Receiver&p=s

This is only the USA models, other regions are 4 ohm compatable, so my owners manual says.

 

[Davemcc]

This is only the USA models, other regions are 4 ohm compatable, so my owners manual says.

I suspect that's because the offshore models are the 220v versions. Unless the OP identifies himself as being from Europe, Japan or some other such offshore locale, that is simply mildly interesting trivia. A 220v offshore model isn't going to do much for somebody here in North America.