Axiom Home Page Forums General Discussion Advice from Axiom Owners M80 tweeter damage - may need a separate amplifier

Hi all, I recently took delivery of the Epic 80 5.1 home theater w/ EP600 subwoofer. If you want, feel free to read the long version of my story here. If not, skip to the words "SHORT VERSION" below.

Like many, the majority of my cartons arrived having taken significant damage due to mishandling with gashes and punctures abound. Luckily I could not find any cosmetic damage due to Axiom's well thought out packing strategy. DHL!%#!&*

Anyway, before ordering my speakers I talked to Brent at Axiom and told him I recently purchased an Onkyo 805. I also told him about the space I need to fill, which is 3,000 cubic feet directly in my listening area that has three walls with the entire right side wall opening to another 3,500 cubic feet, then secondarily opening to another 3,000 cubic feet.... in short, a lot of area. Basically, I live in side-to-side (or California) split home with the listening room on the lower level. The 805's setup screen has a speaker impedance setting of either 4 or 6 ohms. I'd done some reading here and at AVS, and Brent said I should be okay running the 805 provided I set Speaker Impedance to 4 ohms. I received my speakers the other day and have been playing around with placement ever since. During this time, I've been playing the system over 100db at length to get a feel for how things sounded in the secondary and tertiary rooms. I was listening to a Natalie Merchant CD this morning and began hearing some crackling/static distortion from my left M80. While isolating the tweeter causing the static, the same thing began happening with one (or both) tweeters in the other M80, then also a hint of it from my VP150 center.

I shut the whole system down and called Axiom. I spoke with J.C.(sp?) and told him the issues at hand. He said straight away that the 805 isn't going to be a good fit for the M80's and my cubic footage due to lack of power. He stated that switching the Speaker Impedance setting to 4 ohms cuts amp power to keep it from overheating, thereby compounding the power issue. He recommended that I look at a good quality 2 channel amp to run the M80's. I also noted that my speaker runs are in-wall 16 gauge runs, and he recommended I switch to the shortest run possible @ 12 gauge. J.C. was very kind and said to let Axiom know how many tweeters are damaged so they can send replacements. I am a bit confused about the conflicting recommendations from different Axiom folks about all the variables in my setup, but regardless I am very thankful for the top notch service in that they are offering to replace damaged drivers without batting an eye.

{are you still with me?}

My highest priority is to not damage my equipment as I intend to keep it for at least 8 years like I did my last home theatre. I can replace my 16 gauge in-wall runs with direct runs @ 12 gauge at virtually no cost. This, however still leaves me with the power issue, which is undoubtedly the biggest factor here. If that means using the 805 solely as a preamp, then so be it. J.C. said that, with the VP150 and my two QS8's being 6ohm, the 805 should be okay running those provided I set the Speaker Impedance setting back to 6 ohms. I do like to run my system at high volume for house parties and whatnot, so I don't want to ultimately underpower any other channels, and as I said I believe I may have already damaged my VP150.

SHORT VERSION

I have damaged the tweeters in my M80's, and possibly my VP150, while driving them at high volume using an Onkyo 805 receiver. Axiom is kind enough to replace any damaged tweeters, though at a minimum I will most likely need to run the M80's with a separate amplifier. I am debating whether to do so for the VP150 and two QS8's as well. I ultimately have ~8,000 cu/ft of area that I want to fill with sound, and the last thing I want to do is risk underpowering the speakers as I intend to stay with this home theatre gear for years to come. I've read other threads here and know various users run the gamut with amplifiers and the price range they've paid i.e. Outlaw, Rotel, Odyssey, Emotiva, etc.

What are your thoughts people? Stereo amp only? 5 channel integrated? Monoblocks all the way round? Another combo? Any advice is greatly appreciated.

Hello haylo 75,

JC is absolutely correct about not using the Onkyo 805 (or any Onkyo AV receiver) to drive the 4-ohm M80s and I regret that Brent suggested you could do so. As JC has advised you, the 805 will be fine driving the other channels (a 6-ohm load presents no problems for any AV receiver; it's as benign as an 8-ohm load) but you will need a separate 2-channel power amp for the M80s if you continue to use the Onkyo.

In Brent's defense, it's extremely misleading for Onkyo and some other manufacturers to suggest that their receivers will drive 4-ohm loads, THX "certified" or not. Moreover, the manufacturers (almost all of them) use the totally bogus "dynamic power output" spec to mislead consumers into thinking that an AV receiver will not only drive 4 ohms but even produce hundreds of watts into as low as 2-ohm impedances. The receivers will do so for a tiny fraction of a second, then shut down!

The only "dynamic" power output spec that has any meaning is "dynamic headroom" into 4 ohms, which is expressed in dB. That spec is seldom stated because the receiver's amplifier is rigorously stressed in that test.

Ever since I joined Axiom five years ago, I've been warning against using Onkyo AV models for the 4-ohm M80s (based on Axiom customer experience and lab tests by some magazines) as the Onkyos either go into severe current limiting when set to 4 ohms (producing perhaps 30 watts per channel or less), or they shut down.

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).

We do not have enough customer feedback on Marantz and Pioneer to make a recommendation. The one previous Pioneer with Mosfet output devices that would drive the M80s is no longer available.

Regards,

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.

Regards,

Alan,

Thank you for the fast reply and advice. The numbers game driven by the industry is lamentable at best. I am frankly astonished to see the ~30W number.

When it comes down to it, I'm not married to the Onkyo as I've two weeks left to return it. I have a number of HDMI devices so have been looking for something to do HDMI switching for me. Looks like I may be back to the drawing board from a source standpoint!

I'll be damned, I thought we only needed as little as a half a watt for the M80s at decent dbs

Well then my 30 should be more than sufficient!

I noticed you are running a Rotel amp - which model if you don't mind my asking?

I have the RB 1080, it is rated @ 330 into 4 ohm.

If you want to listen to music in other spaces, you really ought to install speakers in those spaces as opposed to blasting your amp in the main listening area. Look at some M3s as they've been getting rave reviews on these boards.

If you want to experiment with the Onkyo 6 and 8 Ohm settings, just turn your gain up slowly. If you see/hear any misbehaviour, turn it down.

By the way, how long are your speaker wire runs?

Are you sure that the 805 is getting adequate ventilation? But now that I think of it, even if it wasn't getting adequate ventilation, it should shut itself down gracefully.

This link says "The 805 is a THX Ultra2 Certified powerhouse designed to drive mid to higher-end home theatres, with speaker impedances from 8 down to 4 ohms - a feat that only a truly powerful receiver is capable of. Its power is rated at 130 watts per channel.". I of course don't believe everything I read & hear but Onkyo seems to be pretty sure of itself.

You could "trade in" or, sell the M80s.............Axiom's M60s, will play real loud, and clean, with almost ANY quality amp/AV receiver.

FYI, I just did some quick googling on the 805 and there are complaints of popping noises in the unit. Apparently the unit also runs very hot as others have reported here and the only way some have been able to avert shut-downs is by installing cooling fans. This doesn't sound good and maybe we should heed Alan's advice.

He just needs a real good amp to do the heavy work for him. It looks like the Onkyo unit just doesn't have the required power at his listening levels. Not everyone can make due with a typical 100 watt receiver.

Thanks for the feedback. I will look into the alternate room suggestion, and in the interim remain cognizant of the fact that I shouldn't worry about filling up so much area with sound from this 5.1 system. I picked up the 805 in part based on the 4 ohm claim, so I'm going to call them tomorrow and see what they say. Based on reports I've read both here and at other places regarding Onkyo's past performance with 4 ohm loads, I'm inclined to believe maybe they haven't quite mastered things with the 805 as much as they claim. I have 6" clearance above the 805 with an open back 8" from a wall and, at this time, an open front. There's typically a glass door on the front, but I've left it off while working with all my new equipment. The 805 does run hotter than I personally like, but this observation is pervasive amongst 805 owners who frequent the AVS forums, few of which AFAIK have had a shutdown due to thermal issues. I haven't had a shut down thus far either.

Unless I have an epiphany or Onkyo lets me in on some magical setting, I am looking hard at separate amplifiers and will most likely use the 805 as a pre-pro. I've read almost universal praise for the price / value quotient that Rotel provides, and I've been looking on and off at Outlaw for years. The Odyssey Khartago is interesting as well. I've located a local Rotel dealer, so I am going to pay them a visit tomorrow.

My wire runs are all in-wall 16-2 Liberty cable. I estimate the left M80 run at 25 feet and the right M80 run at 35. I picked up some 12 gauge wire after going to see The Bourne Ultimatum today... a pretty good action film, but there was too much shaky camerawork throughout. I don't mind a bit of it to mimic the first person feel, but it was pervasive and unsettling in this film. But I digress... The cable was real cheap stuff and I plan to replace it with better wire soon, but I couldn't help but at least shorten the wire runs and use a lower gauge today to see if it had any effect. I wired up the M80's (and my VP150 while I was at it) but I think the damage has been done to all four tweeters. I began hearing crackles and snaps at 65db measured from my main listening position. I did try your suggestion in toggling between the 4 and 6 ohm impedance settings in my receiver's setup menu, but both produced roughly the same results at low volume levels.

The only remaining issue as it pertains to long wire runs with higher gauge wire is my QS8's. I have the same Liberty 16-2 cable run through the ceiling and walls to the QS8's, which I estimate at 40-50 feet per run. There is unfortunately not an easy way to get around using these runs without making my listening room a mess of wires all over. If I had the opportunity to do it all over again, I'd have insisted on 12 gauge wire runs, but I had many other things on the plate when I was building my house.

The QS8's have thus far sounded great with no hiccups. I'm possibly being over concerned due to the M80 issue, but I thought I would ask the experts here if I should contemplate some way of getting heavier gauge wire to the QS8's.

Speaker wire table.

Haylo,

With your distances, you do not need to put yourself out by changing the cable gauge.

BTW, I hate that shaky camera work too. The same happened in Transformers. It feels to me like the director doesn't know how to really create tension and excitement so he hires convulsing cameramen to somehow compensate.

We'd appreciate hearing what Onkyo says about this. Let them know that my cheap, $350 Denon from three years ago that is rated at 90W/channel into 8 Ohms has no issue driving my M80s at over 200W/channel as you can see here.

Good luck!

Rick,

I know I've posted in the past about M80s v/s M60s,and made exaggerated boasts about M60s......but, this time I am serious..........the M80s are not best for everyone's HT/audio needs. To be fair, they do have amplification complications, IMO.
BUT, if one spends the proper time researching the 4 ohm characteristics of speakers, and amps, spend enough money on the one of the amps/receivers that WILL properly drive the M80s....they will be fine.

Larry

Hello Haylo

I have a pair of Thiel CS 3.6's which are also 4 ohm loads. I went with separates ... I picked up 3 Yamaha M80 2 channel amps and an Onkyo Integra M504. The Yammies are stable even with 2 ohm loads. I use one of the Yammie brutes for the Thiels. Never a problem. I use a separate processor - I picked the Integra DTC 9.4 but there are many great processors out there in the price range.

For spec junkies, the specs on the Yammie M80s are superb:

Continuous power at 8ohms 250 wpc THD 20Hz-20KHz 0.003%
4 ohms 330 wpc 0.07% THD
Damping factor 250
SNR 127 DB

A good used 2 channel amp can be a great buy and if you have the room, a breeze to drive your speakers.

Those sound like nice amps. I've been doing lots of separates research since beginning this thread, and increasingly, that is the conclusion I'm coming to in general. I'd really like to see what comes out on the processor market in the next few months to a year though before making a processor purchase. I'm contemplating returning my Onkyo 805 and going back to my 8 year old Onkyo TS-DS777 to use as a processor for the time being. It doesn't have near the options that the new 805 has, but I can live with that for awhile.

I recall an issue I had in car audio with pre-out voltage for some head units not supplying enough power for higher end amps. Nowadays a lot of the car amps, for instance my JL Audio models, have input sensitivity switches to deal with the sometimes wide variance in pre-out voltage. The pre-outs on my 777 are 1V / 470 ohms. I recall the Outlaw 7500 saying it wanted 1.4 ish volts input for full rated output. Is this a figure that's going to differ by a lot from amp to amp? As far as I can recall, I don't see input sensitivity options on any of these home theater amps.

Haylo,

if you are not really on a budget, I would recommend the new Axiom A1400-8 (8 channel amp) especially for your huge 8000cu.ft. room.

This amp will drive your speakers NO problem, and now since you are an Axiom owner, you may be able to phone into Axiom and get the pre-order price (which is now expired at the end of July). The amp has 1400 watts into 8 channels, fully digital and can dump the whole load into 1 channel if needed at any moment. I think the pre-order price was $2900 USD? I forget.

Hutzal,

I am getting the same feeling with my Onkyo 805 vs. the older 777. The 805 has a lot more DSP modes plus the PLIIx and DTS Neo variants, but when I use the modes that were also on my 777 I'm hard pressed to tell any difference.

I unhooked all my Axioms for the time being until I get my new A1400-8. I have been playing around with my old Infinity RS5's and the 805 receiver, and I am pretty sure that the front left channel is clipping at much too low a level (~65db at listening area). I tested two speakers I'm confident are in good operating condition and was able to replicate the issue with both speakers on the same source material. I don't have any equipment to test the amp directly, but I'm going to hook my 777 up just to make sure I'm not crazy.

Regardless, the 805 is most likely a few days away from being boxed back up and returned. I really like some of the features, but I'm thinking it's best to let HDMI 1.3 bake for awhile as I'd like to get a dedicated pre/pro for my next major purchase... of course in doing that the HDMI spec will be updated most likely twice before the companies that take their time with R&D get products to market; rinse and repeat.

Hay, you didn't describe how you determined that "clipping" was occurring, but if that's the case there's definitely a defect involved. 65dB is just about a normal conversational level and the speakers would be using less than a tenth of a watt at that level. Rather than different equipment, it may be wiser to correct the problem with what you have now.

You're right, the volume level was very quiet, which was quite disturbing. I was experiencing massive amounts of distortion, which I took to mean the amp was clipping. It's possible something else was wrong, though I have no equipment to test. Let me know if there is something else I can do in that regard.

I hooked up my 777 tonight and it's running along fine like it always did, so I guess you could say the problem is corrected with what I have now I don't have my M80's hooked up at this time though as the 777 isn't rated to handle a 4 ohm load.

Okay, if at that level there was massive distortion with the 805(regardless of whether it actually fell into the "clipping" category)then your sample of the 805 is pretty clearly defective and should be returned for a replacement unit. Just to check the M80s further, you might connect the 777 to them to verify that they're working well, as is almost certainly the case. The 777 should have no problem with them, at least at moderately high levels(it's THX Select certified), as should also be the case with an 805 in good condition.

As to your previous 805 vs 777 comment, yes there'd be no reason to expect that the 805 would sound better if just the basic amplification was being used, without the different processing in effect. The just slightly higher power capability wouldn't become an audible factor in most instances.

John,

Thanks for the tips. I will try the M80s tonight and see how they sound a normal volume levels on the 777. I am most likely going to return the 805 and save my money for a dedicated processor. There are other issues intrinsic to the model aside from the "real" problems I've discussed here. I don't relish the fact that it runs at a pretty high temperature, plus a ton of users are experiencing loud pops when switching amongst audio streams via HDMI. Initial research indicated this was an issue only when connected to a PS3, but I can replicate it with my Toshiba HD-XA2.

Hey guys,

Sorry I'm falling behind on the posts. I'm away from home visiting my very ill father (and dealing with poor medical management). JohnK is right. 65dB is very quiet and it sounds like there is something very wrong with your receiver.

Mojo,

Thanks for following up. I hope things with your father work out as well as possible.

I talked with Onkyo and they agreed with our collective assessment. I've since ordered an A1400-8 from Brent, so that will be coming (soon?). It's a brand new product and I know generally speaking how those things can go (i.e. my 805), but I have faith in Axiom. I'm going to return the 805 to CC as I do more research on a pre-pro. In the interim I'm back to using my 777, which is humming along just fine.

I appreciate everyone's help as I sort through this. I've been a member of a lot of forums over the years, and there is a lot to be said for the small, tightly knit communities like I see here.

I agree about this board. It's easily the best community I've found online.

And Mojo, I hope for the best for your father, too.

Haylo,

mdrew has been thru alot of AV recievers, and he has rated the RX-V661 in very high regard. I think it may serve as a good pre-pro. I know that my RX-V659 is awesome, although has no HDMI.

Thanks, I haven't looked at Yamaha too much in recent times, so getting into their current line will be fun.

I stopped by the Rotel dealer on the way home from work this evening. Turns out they are a big B&W, Vandersteen and Martin Logan dealer. I live in Missouri, so frankly I feel too many of the local dealers carry M-L. The manager demo'd their flagship room with the pretty nice sounding B&W 802D's hooked up to Classe gear. I am a fan of the kevlar cones... I have Focal PolyKevlar's in my car. The Classe gear was nice, but it sure looked overpriced to me.

I don't know anything about M80s.
but I enjoy Onkyo 900 with Westlake BBSM8 which has nominal 3.8ohm with min 2ohm. I just set Onkyo to 4ohm, no any problem even I turn vol gain to +10dB! before Westlake, I used Tannoy which is 8ohm.

my sp

doubt smallest Denon, say 1508, can drive M80s at 4ohm?

Quote:

---

JC is absolutely correct about not using the Onkyo 805 (or any Onkyo AV receiver) to drive the 4-ohm M80s and I regret that Brent suggested you could do so. As JC has advised you, the 805 will be fine driving the other channels (a 6-ohm load presents no problems for any AV receiver; it's as benign as an 8-ohm load) but you will need a separate 2-channel power amp for the M80s if you continue to use the Onkyo.

In Brent's defense, it's extremely misleading for Onkyo and some other manufacturers to suggest that their receivers will drive 4-ohm loads, THX "certified" or not. Moreover, the manufacturers (almost all of them) use the totally bogus "dynamic power output" spec to mislead consumers into thinking that an AV receiver will not only drive 4 ohms but even produce hundreds of watts into as low as 2-ohm impedances. The receivers will do so for a tiny fraction of a second, then shut down!

The only "dynamic" power output spec that has any meaning is "dynamic headroom" into 4 ohms, which is expressed in dB. That spec is seldom stated because the receiver's amplifier is rigorously stressed in that test.

Ever since I joined Axiom five years ago, I've been warning against using Onkyo AV models for the 4-ohm M80s (based on Axiom customer experience and lab tests by some magazines) as the Onkyos either go into severe current limiting when set to 4 ohms (producing perhaps 30 watts per channel or less), or they shut down.

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).

---

I've been out of pocket for the most part as of late. A lot has been going on on the home theatre front, mainly in getting things set up for my girlfriend's new condo. I found a great deal on some B&W speakers that I couldn't pass up. I picked up a pair of DSM602 S3's, a LCR600 S3 to be used as a center, and an ASW600 sub all at 40% off retail. They're powered by a Rotel RSX-1057 which I picked up at the same time. I've been playing around with both her speakers and mine, hooking both up to the Rotel receiver. I have to say, Rotel means business when it comes to their product. I'm very pleased with the sound quality, power and build quality. There are some features I'd like to see that aren't there, but I'll take the solid amplification I've experienced over a couple more codecs, etc. I currently have my Axioms hooked up and the Rotel is really driving them all very well. What a great receiver.

On a side note, I auditioned a 2 channel RMB-1080 amp for my M80's last weekend and it ran them cleanly and louder than I'd ever like to listen for an extended period. I nevertheless opted to purchase an Axiom A1400-8, which I hope is coming soon!

Have a good weekend, all!

The RB 1080 is a powerhouse of an amp and it does indeed drive the M80s without breaking much of a sweat. I have however got it to run pretty darn warm when cranked up pretty loud. I guess it should be expected with the db levels I sometime listen at.

wid - I was able to get the 1080 to run hot as well... listening at a steady 105dB with peaks well north of 110dB I felt like I'd been to a concert after that listening session. It would have probably run even hotter if I had it installed in my entertainment center... I was just running it with open air on all sides when I had it for the weekend.

What kind of levels are you talking?

It's been a while but I know for sure it was well over 100db, yes I measured it.

Hi Louis,

Yes, actually, the least expensive Denons and Sherwood Newcastles will drive the 4-ohm M80s within reasonable limits in terms of rated output power and room size.

You should know that when you set your Onkyo to the 4-ohm setting, you are actuating a current-limiting circuit that greatly lowers the voltage and current flow delivered to the output devices, thus limiting your Onkyo's power output to a fraction of its rated power.

That's why when you continue to increase the level, you risk clipping the amplifier or pushing it into excessive distortion because the voltage rails are "limited" by the 4-ohm setting.

I'm too a new owner of the Onkyo805 driving my M80. After several days of listening and reading this forum. It's scare me that it could damage my speaker. I about to return my 805 this weekend. I might try out the denon 2308.