M80ti: Problem with Harman / Kardon AVR520

Posted by: dougreding

M80ti: Problem with Harman / Kardon AVR520 - 10/09/02 12:37 AM

I just got a Harman / Kardon AVR520 receiver rated at 75 watts / channel. After hooking up my M80ti's and listening for a bit (awesome!) the receiver starts shutting down by putting itself into standby mode. The only possible explanation I can come up with is impedence problems, covered on the Harman / Kardon website:

"All Harman Kardon Audio/Video receivers can handle most 4 and 6 ohm speakers on the market today. However, there are some manufacturers' speakers that have a minimum impedance well below the 4 and 6 ohm nominal impedance. In this situation, the receiver will protect itself by going into standby mode. This will not damage the speakers or the electronics, but it is an indication that the speaker in question is not compatible with our receiver. Note: The continued use of the receiver with speakers that cause it to shut down can result in eventual failure of the receiver which is not covered by the warranty."

Is this what is going on here? I know the M80ti's are rated at 4 Ohms but I can find no other reason for this to happen. I know these speakers would probably love a separate amp, but this is a pretty beefy receiver and I wont be pleased if it is not sufficient, since I wasn't planning on buying any more equipment at present.

Thanks for any help,

Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/09/02 09:25 AM

Before you go any further, have you tried hooking up to a different set of speakers to see if there is a problem in the receiver itself?
Posted by: Bestboy4

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/09/02 10:46 AM


There has been some discussion on this at the Hometheaterforum web site. It seems that many H/K owners are tracing this shut-down problem to the H/K's finiky power supply. Apparently, H/K receivers can't handle an over unruly power coming from the wall. Appartments are the worst, but it can also happen in a single family house if you have too much on that curcit or if you have your drier, microwave, and blender goning at the same time can cause a power draw and give you noisy power in the entire house. It might be worth trying out a power conditioner or a current stablizer.

Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/09/02 11:49 AM

You make a good point here. While I have never heard of this being a problem with the HK units (but then again not having a HK I wouldn't be paying attention to this) If the HK has a finiky PS then certainly dirty power will play havoc with the unit. There are a number of good clean power sources available at reasonable prices so it may be worth trying. I have a unit on my system and I swear it improved the sound, not drastically and maybe it is even a phycological difference. I have not done any blind tests, and I wanted to add some power surge protection/filtering to protect my investment anyway. These units can't hurt your system and clean power should only make it better.
Posted by: dougreding

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/09/02 09:07 PM

"Before you go any further, have you tried hooking up to a different set of speakers to see if there is a problem in the receiver itself?"

Thanks for the reply - actually to be honest I don't have any other speakers. Before buying this receiver and the Epic 80 set I was just using my computer for music. I can borrow some small speakers however and test this out.


Posted by: dougreding

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/09/02 09:10 PM

"It might be worth trying out a power conditioner or a current stablizer."

Thanks for the suggestion; will a computer UPS work for testing purposes? Or would I need something specifically for audio equipment? Right now I have a Monster Cable power strip which supposedly provides "clean power", but it has no internal battery so I can't see how it could help if the receiver and other equipment is drawing too much current.

I have a computer UPS and am quite familiar with those - not familiar with solutions specific to audio equipment.


Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/09/02 09:34 PM

The Monster Cable power strip much like (although to a lesser extent) the larger units from Monster Cable and several other manufactures provide a source of filtered power, it does not provide any source of stable power. Using a UPS make much difference at this point. You could try it, but if you are already using one of these strips then I suspect that dirty power is not your problem. Even the most basic stage 1 or stage 2 filtering should clean up the power more then enough to rule that out. Look up your model on the Monster Cable web site www.monstercable.com to see what it's specs are. Make sure that it does have filtering and not just surge suppression. Have you tried other speakers? Does the problem still exist or is it gone when you change speakers. It maybe also that the problem only shows up when driving speakers with 4-6 ohm loads. You will need to check this out, if the unit is still new you may want to take it back and have them exchange it for another to test out.
Posted by: Marc_in_Ottawa

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/10/02 03:59 PM

Hi Doug,
I've sold lots of AVR520 with the M80TiSe with no problems yet. The AVR520 has a very robust power supply. The M80TiSe is an 'easy' four ohm load too.
I would suggest checking your speakerwire connections for short circuits at the speaker and amp ends. If one strand of wire is touching the opposite, the '520 will tolerate that at very low levels but as soon as you turn it up, then the protection circuit kicks in. Hopefully you find that's all it is and no servicing is required.
Posted by: dougreding

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/10/02 10:10 PM

Thanks Marc - actually I am using Monster Cable Z1's for the M80Ti's and these have plugs with no exposed wires as I'm sure you're aware. I've looked at the back of the AVR520 and speakers to make sure everything is OK and not reversed and it's fine. Also, I've now tried connecting this to a TrippLite UPS computer battery backup and the same problems occur. Turn it up past -16 give or take and it will go into standby after a few seconds up to a few minutes. Should I be calling Harmon / Kardon now?


Posted by: dougreding

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/10/02 10:20 PM

Hi John - I did indeed try a beefy TrippLite computer UPS on the battery jack which provides constant filtered power and had the same problem. My Monster Power strip is the HTS850. It does indeed have clean power as a feature, "Stage 1 Clean Power." I guess since the AVR520 has been going into standby while connected even to a UPS we're dealing with something else here.

As far as testing other speakers goes, the only ones I have now would likely be blown if I crank the AVR520 up to the point where it cuts out. Marc has sold this particular setup though and apparently he hasn't seen this unit have any trouble with the M80Ti's.

Is there anything else you (or any other forum members) suggest I might try or should I assume I have a bad receiver?


Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/10/02 11:18 PM

If you have followed Marc's suggestions and checked the connectors for any shorts and you have done everything to verify you have a good power source (which I see that you have) then I would say it issafe to assume that you are dealing with a problem in the unit. At this point like I said before, if it is new unit take it back and get them to either service it; or if it is brand new get them to replace it. Don't waste any more of your time.

Now that aside, when you the level would blow the other speakers. How loud are you taking about here. I would ask Marc to help you here as I am not familiar enough with your unit as to the volume levels you can drive this at. But any unit if it is being driven hard or starts to heat up too much will go into protection mode. How long does it take for this to happen?
Posted by: dougreding

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/10/02 11:53 PM

Many thanks for your assistance John. I would say that anything louder than -16 places the unit in danger of going into standby mode. More bass, or turning the bass up, makes it worse. As far as how long it takes - *usually* it is rather fast, within seconds of cranking it up past -16 db. I have listened to nearly an entire CD at this volume however without it kicking into standby, but this is rare. Generally the AVR520 does not have nearly enough time to even get warm before it goes into standby mode. I have not tried listening to it for extended periods at low levels however. I suspect that at lower levels it won't happen.

BTW I got the unit at BrandsMall.com for $630 shipped if this makes any difference. The service was good and the unit was shipped quickly but I've never dealt with them before on a problem item.

Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/11/02 12:06 AM

Doug, you very welcome

I think that unit should be happy playing all day at that volume setting. I was thinking you were going to come back saying somewhere in the plus. I think you should give them a call and they more then likely will exchange the unit. Given that this is new. If not then you would be looking at sending the unit too an authorized HK dealer to look at it under the products warranty.
Good Luck and I hope everything gets resolved for you quickly. I know how frustrating this can be.


Posted by: dougreding

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/11/02 12:10 AM

I'll be calling them tomorrow, and you're right it is indeed frustrating. This type of thing wouldn't bother me nearly as much on a $200 receiver. For me, defects become less and less acceptable as price goes up. I know one can never expect perfection but after a certain price point, anything less just fries me up.


Posted by: chesseroo

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/11/02 12:45 AM

I agree with you there Doug.
After a certain price point, one would expect some superb customer service and strongly performing equipment.
However, my 13 month old Maytag washer (just below their top of the line Neptune series) crapped out. It is just past the 1 year warranty for labour so it just cost me $110 for repairs (parts were free). Took nearly two weeks to get a guy to my house due to their tight schedule.
Do you know what its like to recycle your clothes for 2 weeks?
Ya, its frustrating.
By the by, the cable in my washer was 22 ga lamp cord.
Posted by: murphyman

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 10:10 AM

I have an onkyo receiver that was hooked to a pair of older 4ohm vegas and I could crank the hell out of them with no problems.picked up a pair of m-80's after being told by axiom my receiver would be abel to handel them no problem.......WRONG!turned up the volume to a moderate level and triped off the auto protect.a little bit of heavy bass and off went the protect.talked to the members of this board and got the same results,you should be o.k. check this,check that,it must be this,it must be that.wrong!the answer is quite simple,the m-80's are power hogs!you're receiver will not be able to handle the power consumption of the m-80's.the correct solution is to either pick up a 400 watt/channel power amp or sell the speakers.for some reason these members on this board and the company it's self keep steering unsuspecting consumers to to the m-80's telling them thers no reason you should'nt be able to power these speakers with you're a/v receiver.on the other hand I did pick up an outboard amp and I'm extremly pleased with the results because my m-80's now can finaly sing.
Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 10:59 AM


I think that your comments are a little out of line. The M80's are not power hogs, they are actually a very easy 4 ohm load for receivers to drive. You do not need 400w per channel to drive a speaker just because the rating says it can HANDLE 400 watts. A measure of how hard it is to drive a given speaker is reflected in the efficiency rating of the speaker such as 95db@1w/1m. the lower the number for example 85db@1w/1m the harder (more power it takes) to drive that speaker. The M80's are actually one of the easier 4ohm speakers to drive. You should really try to understand ratings and specs before you spout off. There are lots of people running these speakers on lesser amps with no problems, and on the same amp as Doug has with no problems. I have run these units off a Yamaha RXV995 a Denon 3802 and now off the Denon 5800. I have even tried them on an old Sansui G5700 just for the hell of it, that is not even rated for 4ohm speakers with no problems at any level.
Posted by: murphyman

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 12:07 PM

it seems that alot of people have no problem running their 80's off a 50 watt per channel receiver.I'll even bet you I can run them off a cheapo 25 watt receiver but whats the point of even buying these speakers if you can't get them to stand up!I bought the m-80's for power and sound.take a good look at them on axioms web page,six drivers and a power rating of 400 watts!these speakers are not for mellow listening and for small rooms there built for power.sure they sound good at low levels but my point is most a/v receivers can't handel these speakers.my 787 could'nt as for alot of other people on this board who seem to have the same problem.I feel the m'80's are an awesome speaker but this company in my opinion dose or has misrepresented these speakers to the customer on what kind of equipment you can use with them.I don't recall any posts saying my auto-protect keeps going off on my m40'm-50'or m-60's and their sensativity ratings are lower then the m-80's.I feel that I"m not out of line here and only stateing what I have experienced.I would recommend axiom speakers to any one but tell them you need some serious power to run the m-80's.
Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 12:24 PM


Your own argument defeats your point. Power handling is not a measure of what is required to drive the speakers. The 60 with less sensitivity require more power to equal the SPL of the 80's.
Posted by: murphyman

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 12:30 PM

try reading it again......the m-60's are less sensitive so they do require more power but they don't seem to be triping off peoples receivers because they don't draw more power from the amp..higher ohm rateing....
Posted by: chesseroo

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 12:54 PM

your post is rather inflammatory by essentially blaming the people on these forums for the obvious fault of the H/K receiver.
I don't believe the 4ohm M80s need massive amounts of power to get them to work properly. People have driven the m80s with receivers that had far less power specs and some were not even rated for 4ohm speakers (look around some other forums for this info or pose your question about it to Alan or Ian). If the H/K IS rated for 4ohms, then the fault lies with H/K, not Axiom.
It is quite apparent that the annoying protection circuitry of the H/K AVR520 is more sensitive than people realize. But how do you expect the forum posters to know that unless they actually owned this receiver? If they are giving someone advice about whether a receiver should be able to handle a certain set of speakers, the most information they have to provide advice comes from the spec sheets on the product.
There is no reason (after looking at the H/K tech specs) that the AVR520 should have any issues whatsoever.

Take up your beef with the person who sold you the H/K or Harmon Kardon the company. Don't get angry at the forum posters who understand the specs required and the specs given. It was all i had to use in deciding and committing to my first receiver purchase and i don't have any complaints. Mind you , i also bought a receiver that DOESN'T have protection circuitry. My last Technics system did and i realized i NEVER wanted to see that cr@p again!
Posted by: murphyman

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 01:17 PM

not just h/k but also onkyo and dennon I've see in posts that the m-80's were triping off the auto-protect and there was even one guy on this board who listened to me after trying the half dozen other suggestions and wrote back to say "YOU WERE RIGHT' but maybe you're on to something with looking for a receiver without the auto-protect....ever see an amp light up from pushing it to hard? It seems to me that alot of people on this board protect the m-80's from this topic when it is very clear to me that most a/v receivers of today don't do well with the m-80's.no big deal but people who do have problems with this issue seem to get more of the run around then help.its the power supply,the wall plug,you're cabels.etc.etc.etc.its simple trade up for a pair of m-60's or get more power. oh and sorry to hear about you're inflamation........
Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 02:25 PM

I think that you are over generalizing here, Even though many lower end receivers state that they are capable of driving 4 ohm loads the power supplies in them are just not up it. With many such amplifiers, you can drive a 4-ohm load safely, as long as you don't try to drive it too hard. If you drive a low-Z load to too high a volume, one of several things may happen: the amp may begin to "clip" (sounds very harsh and distorted, may damage the tweeters), or may overheat and shut itself down, or in the case of units without a protection circuit built in may overheat and burn up.
In your saying buy more power, you are overlooking the main problem that resides in the flaw of the receiver. I would challenge you to find anyone with the likes of the Denon 3802 the Yamaha RXV1000, or the one of the better Onkyo amps that has this problem. In your buying more power you have also bought yourself a much better power supply that can handle the 4 ohms at higher current levels. You DO NOT need all that power to make these speakers work. You do need a unit that can provide the current, I donít care if the amp is 600 watts if the transformer cannot deliver the required current for a 4 ohm load you will have problems. A 50watt high current amplifier will do just as good a job driving these speakers as any. The bottom line it was the receiver not the speakers that were your problem.

Posted by: murphyman

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 04:54 PM

my receiver is an onkyo 787 HIGH CURRENT a/v receiver.new it listed close to a grand and was supreceded by the 797 for prologicII. what is the weak link in this receiver?is this a lower end receiver?I have had several people on this board tell me I should not have any problems with this receiver and I should have more than enough power to use m-80's but the receiver says no way.I even talked to onkyo and they said it was the speakers and not the receiver.so if you can please tell me what the problem is exactly and what I can do to fix it other than an outboard amp.I'm sorry I ticked a few people off but I see this stuff go on alot on this board about this subject and I would have been prety upset if I paid serious bucks for a pair of speakers that did'nt work with my system after getting the go ahead from the company and members of this board.come to think of it thats exactly what happened.
Posted by: chesseroo

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 10:06 PM

Murphy, unfortunately i cannot directly compare your problem with the Onkyo 787 and the M80s however i can at least tell you about my setup and present experience.
My Onkyo 797 is normally hooked up to M60s but i have had a friend come over and test out his Kef's which are 4ohm rated. The 797 drives them without any problems and this is without having changed the setup options from 6ohm to 4ohm.
I really do believe that 787 should be up the challenge. But maybe it simply is not.
Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 10:16 PM

The weak link in the receiver is the power supply. And yes for 4 ohm loads that is a lower end receiver. Why don't you connect the M80's to your receiver, and hook them up so as to present them to your receiver as an 8 ohm load. Then see if you can get it to shut down?
Posted by: murphyman

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/12/02 11:41 PM

my 787 has no switch to go from 4 to 80ohm so no go there also it states the 787 is rated at 6 ohm.I have used other 4 ohm speakers with this receiver with no problems at all.what are some good 4 ohm load receivers that are comparable with the onkyo 787?and why is this a lower end receiver? same amp and power supply as the 797.who knows maybe Onkyo makes junk.as far as kef speakers go they may have a 4 ohm rateing but it's a diffrent speaker all together so you can't compare
Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/13/02 12:24 AM


Having a 4, 8 ohm switch would not help you in hooking up the speakers as an 8 ohm load. There are 2 ways you could do this.

1. use 4 ohm 15-20 watt resistor in line to make the amp see the load as 8 ohms, you will have to be careful with this as the resistor will eat up a lot of power which is dissipated as heat so it will get warm it may get very warm depending on how high you drive it. Also the resistor will change the response of the speaker but it is not sound you are testing.

2. Hook up the speakers in series; this will also present the load to the amp as 8 ohms.

I would not say that Onkyo makes junk they make some very fine products, but you also have to realize that the 787 is targeted at a certain market, and for the most part people who buy this receiver also will buy speakers within a given price range. And for the most part these speakers are 8 ohm. One of the areas that manufacturers cut costs, is in some of the most expensive components. Amplifiers capable of delivering high current for low impedances requires discrete output transistors to carry the current, large heat sinks to dissipate heat, big filter capacitors, and massive power supplies all of which are expensive components. To make the receiver in that price range some this is sacrificed.

When a speaker impedance rating is given the value stated is a nominal value a 4 ohm speaker could be anywhere from say 5.5 down to 3 ohms. For the most part it is the flagship receivers of these companies Denon, HK, Onkyo, that are capable of driving these loads without any problems. Any receiver that is THX Ultra Certified is supposed to be capable of driving speakers down to 2 ohm loads. The power supplies in these units have to be capable of delivering the high currents required to do this, so a 4ohm load is not much of a problem for them. To your model of receiver that 2 ohm load is like a dead short it will go into protection mode immediately. When you connect to a 4 ohm load the unit can drive this at low volumes, the minute you begin to push this the unit heats up and will very quickly into protection mode. I think that your confusion layís in the current vs power thinking you have. High current does not mean high power. You can have 400 watt amplifier that can drive 8 ohms very well but the unit does not have the capability to deliver enough current to drive a 4 ohm load. On the other side of this you can have 50 watt high current amp that will be happy to drive 4 ohms all day long if the power supply was designed to do so.

Posted by: murphyman

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/13/02 01:11 AM

so basicly you are saying that my 80's are drawing too much power from my thx select tx-ds787 receiver and setting off the auto protect.right?you also stated that my receiver is marketed for a cheaper or less performance speaker other than the m-80's,is this also correct.so for these reasons my onkyo cannot handle the m80's.this I all agree with and have stated in the past posts is what should be told to people right off the bat.in basic the m80's require more power than what my receiver can handle,a thousand dollar receiver can't handle these speakers? its not the power output required but the power consumption. so in you're opinion what would have been a better choice for this type of receiver and why?
Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/13/02 01:39 AM

No, again you are confusing power and current. Simply stated speakers do not draw power from a receiver. The speaker functions simply as a result of the voltage and current supplied to them. The 4 ohm load of the M80 requires your amp to deliver more current to them then does the 8 ohm load of the 60 for the same power. From what you are telling me is happening I would surmise that the Power Supply of this unit is not capable of delivering the current load required without overheating. I would say that looking at the specs on the Onkyo web site that this unit should be capable of running the 80ís without too much trouble, and looking at the published specs, my only concern is that it would run a bit hot with the 80's 4 ohm load. I feel that the problem lays with Onkyo not Axiom on this. If you can get the specs of the power supply from Onkyo you should be able to calculate roughly what this unit is really capable of. Obviously there are some short comings in the design of this unit, you cannot blame the speakers for this, nor can you expect that Axiom test their speakers on every receiver made. They like I do, would look at the specs given to them for the unit and from this deduce whether or not it should work with a given speaker.

Posted by: murphyman

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/13/02 10:28 AM

sorry I did'nt word everything proper.lets go one more time,MORE current is required from my amp when driving the m-80's to produce the same power as the m-60's.as LESS current is needed for the m-60's to create the same power as of the m-80's.so just because onkyo stamps high current on there stuff dosn't mean so. the funny thing is that the receiver would trip up without getting hot at all and if I wanted to I could almost trip the protect mode almost instantly. is it possable that the m-80's might be dipping down below the 4 ohm rateing?it all comes down to ohm's is the measurement of resistance,less resistance equals more current flow,equals more current demand from the amp.or should I say more current flow threw the amp's power supply?
Posted by: BBIBH

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/13/02 11:25 AM

Having followed this thread with great interest...I must comment on your recent post.

You are making several fundemental errors in judgement:
- low power equals low priced (this can be true, but there are many low powered amps that are expensive. They have, as others have tried to explain, rugged power supplies that can deliver high current. Please note, there is no "level" that must be reached before a mfg'er assigns the model "High Current". I have driven many of the Axiom lineup-yes including the 80's- with a 20 and 40 watt NADs) Also, high power does not mean high current OR high current does not always mean high power.

- all people who buy the 80s will want to attain concert hall volumes, simply because they have many drivers and are large in size: again, you also mention they sound nice at low levels. People who want quality sound would be listening at many volume levels, and not always LOUD.

Certainly, you are not out of line in mentioning what you have experienced, and it would be wrong of any board member to say so. But, you are stating that the company has "misrepresented these speakers to the customer on what kind of equipment you can use with them" - to quote your post. Can you point me to the claims of Axiom Audio/Colquhoun Audio Laboratories that they have made about your equipment? I ask, as I may have missed that.

The bottom line appears to be that this combination does not work for some, but has worked for others(if my memory of threads serves). If that is true, were does the problem lie?
Posted by: murphyman

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/13/02 12:33 PM

before I purchased my m-80's I did what so many others did on this board and asked a stupid question,will the 4 ohm load be a problem with my receiver?apparently this is a difficult question to answer because of the grey area where a/v receivers can and cannot perform.to all less experienced in audio we can get confused between power rateings and current,but all we know is it should work,we shell out the money,hook up the speakers and have a problem.then I see these people ask on this board and it's the same old stuff....try a power conditioner,try better cables,you have too much stuff hooked to the circuit.etc.etc.etc.and then now I hear the problem is not the speakers it's the manufacturer of the receiver.so here is the question at hand.I have a such and such receiver rated at 6 ohms bla bla bla...should I get the m-80's that I"m really intrested in or will I have a problem? I get you'll be fine with the m-80's,go ahead and send us you're money.In all honesty if I would have received an answer like you may have a problem because these speakers may not be compatiable with you're receiver try the m-60's instead,then I would have probably looked somewhere else for my speakers.but the company wants to sell speakers.afterall thats why there in buissness.then I state my opinion here on what I think is going on and get "I find you're post inflamitory,I have no problem running these speakers on anything.bla bla bla...the bright spot is that these speakers do sound awesome after I spent close to a grand on an amp but that was not the direction I wanted to go.serves me right not knowing my stuff about all the details of a/v receivers and speakers..o.k. everyone,let the flaming begin............
Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/13/02 03:10 PM

I understand you frustrations and can sympathize with them. We donít all have 4 or 5 grand to shell out on a companyís flagship receiver. We look at the specs try to form intelligent questions and get the opinions of others, and in most cases the opinions of others are based on the same information you have. Unless you run across somebody that has the same unit and has tried exactly what you are doing; you donít get a voice of experience. What you get is the opinion of a lot of users some very a lot of experience and others with limited experience that have similar products and have done this successfully or unsuccessfully whatever the case may be. As previously stated that if I or anybody else with some measure of experience looks at the specs for your unit, I would expect given the details that Onkyo have put down in their spec sheet that this unit should work with the 80ís and that the only problem I would expect to see is that the unit would run a little hot. If I had bought the speakers and then run into the problems you have I would begin by looking at all the variables that can affect my unit from working correctly. Remember this unit now has to work harder to drive these speakers then it would running an 8 ohm load. So these would include dirty power, wiring problems, speaker connectors that have strands shorting to the other binding posts, and also making calls to Onkyo. I think the flaming begins with your statements that Axiom deliberately miss leads customers just to sell speakers. Show me some proof of this, I cannot find any searching through the posts or the Faqs. When I look at this I find that the Onkyo specs could also be construed as miss leading. So who is really to blame here, the speaker maker for putting out 4 ohm speakers, Thier opinion of whether or not this should work is based on experience of others and the specs given by Onkyo, or is the receiver manufacturer to blame for not making the unit capable of driving 4 ohm speakers? They do not in their literature clainm to be able to run 4 ohm but they do for some reason given a power output rating for speakers down to 3 ohms; which I find a little amusing and given your experience miss-leading.
Posted by: alan

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/13/02 03:27 PM

Hi Murphyman,

I have posted on the boards in the past and generally steered questioners away from Onkyo receivers and 4-ohm loads, and I answer these questions daily in private emails (advice@axiomaudio.com) as well as taking phone calls on our toll-free line on Wednesdays and Sundays. I've also commented on the inadequacy of power supplies in multichannel receivers on these boards. For the most part, in the multichannel mode, these receivers are measured at one frequency (1 kHz), with one channel driven. The brochures and advertising literature do NOT specify this (no surprise there). And ignore advertising claims of "high current"; that phrase has been tossed around for years by ad copywriters and distributors who don't understand the basics of Ohm's Law and power supplies.

When some of the Onkyos are lab tested by Sound & Vision magazine, with all five or six channels running simultaneously into 8-ohm loads, the protection circuitry shuts down the outputs or severely limits the power output.

For example, the results of independent tests by Sound & Vision magazine (July/August 2002) of the Integra DTR-7.2 ($1,200) vs. the Denon 5803 ($4,300) and Yamaha RX-Z1($2,799) are very revealing of the Integra's current output limiting circuitry and its power-supply limitations.

The Integra is rated at 100 watts X 6 channels. In the bench tests, it produced 141 watts into 8 ohms with one channel driven. With five channels driven, its output sank to 54 watts per channel, and with 6 channels driven, it produced 38 watts per channel and shut down. And this was into 8-ohm loads! Think what would have happened with 4-ohm loads! Onkyo has current-limiting protection circuitry because its power supply isn't up to these admittedly very demanding bench tests. That's why they can sell it a fraction of the price of the Denon and the Yamaha.

(In the same tests, the Denon produced 118 watts per channel, the Yamaha, 109 watts with 7 and 6 channels driven, respectively. They did not shut down.)

As John Henderson has pointed out, the "nominal" impedance rating is a kind of average, usually erring on the side of caution. And one 4-ohm speaker may have quite a different impedance curve than another, and may touch 4 ohms at different frequencies.

You can look at the M80ti's impedance curve at audiovideoreviews.com. Click on the measurement symbol. The M80ti dips to 4 ohms between 40 and 50 Hz, rises, then remains at 4 or 5 ohms up to about 800 Hz, after which the impedance is much higher out to 20 kHz. It never goes below 4 ohms, but it's definitely a 4-ohm speaker, and it will draw more current at the frequencies where it's impedance hovers around 4 ohms.

All of John_Henderson's comments are very accurate, and I can only suggest that anyone thinking of getting 4-ohm speakers who prefers high sound levels, he should scrutinize independent test reports of multichannel receivers very carefully consider separate power amps over a receiver. So far as I'm aware, Sound&Vision is the only magazine that tests A/V receivers with all channels running simultaneously. And even there, the info is in a technical "sidebar" at the end of the report. So read the fine print.

Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/14/02 12:47 AM

Very Nicely stated Alan,

I must haved missed that S&V issue, I will have look it up later when I can keep my eyes open. I just got my 5800 back on Friday from having the boards and software upgraded to the 5803 revisions, so I would like to see what they have to say about the 5803. So far I am happy with the results of the upgrade.
Posted by: polara

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/14/02 07:21 AM

ill post this again
stereo power rates from s@v
my rxv1 is good-
Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/14/02 10:38 AM

The RXV1 is a nice unit,you should be very pleased with that receiver, and I have heard great things from people that own it. The RXV1 was one of the receivers that was in contention when I was researching what to but. The other unit that I was considering was the Marantz SR14EX. In the end for me Denon was what I went with.
Posted by: dougreding

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/14/02 05:14 PM

Very interesting to see what a thread this has become.

I have another question, back to the HK AVR520. What about testing the M80Ti's with the bridging bars removed and seeing if the 520 still goes into protection mode?

In the mean time, I have set up the M80Ti's in the receiver as "small" speakers, and have handed over the bass handling solely to the EP350 subwoofer. So far, this seems to be working OK. Still, I definitely want to resolve this and I guess if that means buying an amp, so be it.


Posted by: JohnK

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/14/02 08:08 PM

Doug, until you mentioned otherwise, I assumed that you were setting the speakers "small". With a sub as good as the EP350, I'd think that that is the preferable setting, even with the good deep bass of the M80s.

On the test you propose, I assume that you mean leaving only the upper terminals connected so that the M80 woofers won't be operating. That would be interesting and I'd guess that there would be no protection mode problem since the woofers would be completely out of the picture,instead of just rolled off under 80-90hz in the "small" setting.
Posted by: dougreding

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/16/02 03:58 PM

I guess I should have specified that, sorry. I had the speakers hooked up (without the sub) in "large" mode. I'm still pretty surprised that an HK AVR520 can't drive the M80's in large mode with no other speakers connected. However, with the EP350 hooked up and the M80Ti's in "small" mode, everything seems to be OK.

Since "small" mode cuts the frequencies below 90hz off, is that where I should set the EP350 crossover?

And you're right, the EP350 is quite a capable sub.

Posted by: jkohn

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/16/02 04:45 PM

In reply to:

Since "small" mode cuts the frequencies below 90hz off, is that where I should set the EP350 crossover?

First, the x-over doesn't cut-off, it rolls-off, so your speakers will still be getting a signal below 90hz, just not as much. Second, if you're using the receiver's x-over, you don't want to use the sub's x-over, so either turn it off if possible, or set it as high as possible to get it out of the way. You don't want both the sub and receiver x-overs active at 90hz.
Posted by: JohnK

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/16/02 05:33 PM

Doug, I agree with Jeff. To get the EP350 crossover as far out of the way as possible, the best procedure in general is to turn it to the 150hz max and leave it there.
Posted by: JohnK

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/16/02 05:51 PM

Doug, I should also add that I share your surprise at the problem. Marc reported here that he's sold many M80/520 combos with no problem, so he's certainly knowledgeable on the point. It may still be that something in the protection circuitry of your 520 sample is out of whack(to use a technical term)but maybe it's best to leave well enough alone.
Posted by: john_henderson

Re: M80ti: Problem with Harman / Kardon AVR520 - 10/16/02 06:09 PM

It would be interesting to find out if Marc has actually tried running them set to large or knows if any of the customers run them set on large, or have they by default just gone and set them to small without even trying it as Doug has?