Axiom Home Page Forums General Discussion Stereo Ahh HA! Good news for the old girl

I have been back after a long break with no additions to my HT but I am again getting the itch to upgrade. I currently have a Yamaha RXV2700 which has been an excellent piece for my HT but I was worried how it would work with a 4 ohm load. I did test my infinity's paired to make a 4 ohm load and I did not have any problems. After all this time I have proof that the RXV2700 can handel a 4 ohm load even though Yamaha never put any 4 ohm ratings on anything. It appears that "Into 4 ohms, the RX-V2700 was able to deliver continuous power levels at a
whopping 272wpc x 1 and 230wpc x 2 with less than 0.1% THD + N." This was take from the following article http://www.yamaha.com/yamahavgn/Documents/YEC/AH_Yamaha_RXV2700.pdf writen by Audioholics I knwo it is not alot of power but I am no longer scared of the M80's LOL but would like more power .

Later Phil

Phil, "not alot of power"?? On the contrary, those numbers show that your 2700 could drive the M80s to well beyond safe(to your hearing)listening levels. Both that and your own test should give you confidence.

The nominal 4 ohm rating stated by manufacturers means nothing in and of itself. Like most things with this industry, standards are lacking or don't exist. There is no standards in place which manufacturers have to adhere to when measuring or publishing loudspeaker impedance. You can't assume that since one brand of speakers can handle the receiver another 4 ohm nominal rated speaker will too. One set of speakers could be rated at a nominal 4 ohm with impedance minimums at around 4 ohm. Another could be a much harder speaker to drive rated at 4 ohm and having multiple impedance minimum's below 4 ohms dipping in the 2 range in the lower frequencies.

You really have to look at the impedance or better yet impedance and phase vs frequency to get a good idea on how demanding the speaker will be and the interaction with a receiver/amp. Unfortunately these type of specifications are rarely published.

Education can go a long way because when consumers see 4 ohm rated speakers they naturally freak out, but what they should be really worried about is the impedance minimum's and where they are occurring. This is one area that could use a lot of work with setting proper standards in place on specifications for all manufacturers to adhere to. It might also help decrease some of the panic that ensues and allow consumers to make better and more informed purchasing decisions.

Those specs are similar to my 3808 and it has no problems running my M80s to over 100db, that is more than ample amounts of power for most listening conditions.

Yes I was just happy to find some information on the 4 ohm ratings, I do know that some 4 ohm speakers do dip down below that rating but as stated there is little information out there on this. Anyone know how low the M80's dip to or if they dip at all? I really guess that this means I do not have to purchase another toy for my HT in the lines of a secondary amp then if I get the M80's.

Would there be a benifit to even adding a Emotiva UPA 7 rated at 185w/4 ohms which is rated lower than the 2700 anyway? I could see adding a XPA-2 for 2 ch stereo at 500W/4ohms..correct?

My room is not overly large in at 2300 cubic feet so the M80's will be more than enough for that size rooom and I will not be able to have them running at mind bending levels in that samll of a space.

Thanks for the input
Phil

I would suggest you trying your Yamaha first and then see if you need something more. My guess: you probably won't.

I have an LPA-1 which is the precursor to the UPA-7. For channels 1-5, they're the same thing. I bought it because my old Pioneer Elite (VSX-43TX, 2002) really did have issues driving my M80V2's. At high volume, it would start to clip. It's quite audible. The LPA-1 does a fine job driving the M80's. I can turn it up as loud as my ears can stand without any audible nasties. I've had it for almost 3 years now, still works perfectly. So for me, there definitely was a benefit to adding the amp.

Give the Yamaha a thorough chance. Crank it up. If you get to a point where it's not loud enough for you and the sound quality starts to degrade (or the Yamaha shuts down), then go buy an amp. Personally, I'd go with the XPA-2 driving the M80's and let the Yamaha do the other channels. But that's just me.

Oh, and regarding the M80's impedance. There was a bit of a fracas a couple of years ago between Emotiva & Axiom (fans) over this very topic. A couple of our more well-known board members here had problems with some of Emotiva's high-end amps and their M80's (not sure if they were Ti's or V2's). If my memory serves, Emotiva and a few trollish posters claimed that the M80's crossover design was suspect and had a bad impedance dip down to near 2-ohms at low frequencies. Axiom supporters (I don't think Axiom directly) claimed that Emotiva wasn't telling the whole truth about their amps specs, since many mass-market AVR's and other amps had no trouble with M80's. A bit of tit-for-tat ensued, both here and over on Emo's discussion board. AFAIK, it all ended amicably with the affected persons getting full refunds.

But, IMHO, it's left a bit of bad blood between some Axiom and Emotiva supporters. At least, that's the impression I get from participating here and on Emotiva's forum.

It's a moot point now anyway. Axiom has made changes to the M80 crossover's since this happened (the V3, if not the V2). And Emotiva has discontinued the line of questionable amps (MPS-1).

What Bruno and Peter said