Power Ratings in Modern AVR's

[Verdinut]

I've seen no setting whatsoever to set the receiver to various impedance. It was my understanding that the receiver just automatically detects the impedance and adjusts automatically as needed. I need to look at the manual on that one. Great point!

If your manual is written as that for my SR5010, you go to the Speaker Connection page.
At one point, it should tell you how to carry the settings for lower impedances but you should make sure it is set for 8 ohms.

 

[TLS Guy]

Yeah that's about the size of it. Nothing at all is telling me it's a speaker issue at this point.

I don't believe for a moment that changing your AVR will solve your problem. If you used the full power of any AVR on those speakers, those small drivers would be toast pronto. Very likely they are damaged from over driving

This thread had cast aspersion on the power rating of AVRs. Well I have news for you. The power rating of speakers is almost always wildly exaggerated, and I mean wildly.

I had a salutary experience today.

I had a suspicion my center channel had been loosing a little of its luster, with dialog just get harder to understand. Since I'm 70 I was thinking it might be my hearing. Everything was fine in two channel though.

So I got the test rig out and the top end of the center was down 5 to 6db.

So I removed the drivers. The tweeter of the SEAS coaxial that carries the top end from 2.9 KHz and up showed a DC resistance of 1.6 ohms, when it should have been 4.8 ohms. So I did a postmortem on the tweeter from the driver and sure enough the VC was markedly blackened. So it has some shorted turns in the VC coil.

SEAS rate the tweeter at 220 watts short term and 90 watts continuous. I can tell you that is fanciful for that coil by a big margin. I used a third order electric slope rather than the second order slope at 2.9 KHz recommended by SEAS to add an extra margin.

Luckily I had a spare driver on hand, so things are back up to snuff.

Parts are on the way to rebuild the driver, and I should have it repaired by week's end.

The speaker was driven by a Quad 909, 150 watts into 8 ohms and 250 watts into 4 ohms. The tweeter is 6 ohms. The tweeter us unlikely to have ever have been driven out of spec, but possible I suppose. I highly doubt it though. The coil was charred and the ferro fluid in the gap showed signs of over heating.

I can tell you that any receiver you could purchase is powerful enough to easily damage the speakers you have and fast.

Since you have got back into AV I suspect that that you have been playing your rig louder, and you may very well have damaged drivers especially the woofers which are most vulnerable.

So before going to the trouble of packing up that AVR check the DC resistances of all your voice coils against spec. There is a good chance you will get a nasty surprise.

 

[TLS Guy]

I've seen no setting whatsoever to set the receiver to various impedance. It was my understanding that the receiver just automatically detects the impedance and adjusts automatically as needed. I need to look at the manual on that one. Great point!

Some older receivers had an impedance switch to limit power into lower impedance loads.

The only amps that are required to have their impedance matched to load, are tube amps, and MAC power amps that have auto transformers between the power transistors and the speakers. I think the later is a terrible idea by the way.

Direct coupled solid state amps will increase current to the load as impedance drops. Some will become power limited. If an amp gets a low impedance load it is not happy with, it will go into protection or blow up and often both.

If you do change receivers get the Yamaha. Pioneer are now part of Onkyblow.

 

[Verdinut]

Some older receivers had an impedance switch to limit power into lower impedance loads.

The only amps that are required to have their impedance matched to load, are tube amps, and MAC power amps that have auto transformers between the power transistors and the speakers. I think the later is a terrible idea by the way.

Direct coupled solid state amps will increase current to the load as impedance drops. Some will become power limited. If an amp gets a low impedance load it is not happy with, it will go into protection or blow up and often both.

If you do change receivers get the Yamaha. Pioneer are now part of Onkyblow.

Marantz receivers still have a setting recommendation for 6 and 4 ohm loads.

I have an SR5010, and on the Speaker Connection page (Page 34 of the Owner's Manual), it indicates how to modify the setting.

I am driving 4 ohm speakers and, of course, I ignored their silly recommendation.

 

[TLS Guy]

Marantz receivers still have a setting recommendation for 6 and 4 ohm loads.

I have an SR5010, and on the Speaker Connection page (Page 34 of the Owner's Manual), it indicates how to modify the setting.

I am driving 4 ohm speakers and, of course, I ignored their silly recommendation.

Good because that is just a power limiter.

 

[Halon451]

I don't believe for a moment that changing your AVR will solve your problem. If you used the full power of any AVR on those speakers, those small drivers would be toast pronto. Very likely they are damaged from over driving

This thread had cast aspersion on the power rating of AVRs. Well I have news for you. The power rating of speakers is almost always wildly exaggerated, and I mean wildly.

I had a salutary experience today.

I had a suspicion my center channel had been loosing a little of its luster, with dialog just get harder to understand. Since I'm 70 I was thinking it might be my hearing. Everything was fine in two channel though.

So I got the test rig out and the top end of the center was down 5 to 6db.

So I removed the drivers. The tweeter of the SEAS coaxial that carries the top end from 2.9 KHz and up showed a DC resistance of 1.6 ohms, when it should have been 4.8 ohms. So I did a postmortem on the tweeter from the driver and sure enough the VC was markedly blackened. So it has some shorted turns in the VC coil.

SEAS rate the tweeter at 220 watts short term and 90 watts continuous. I can tell you that is fanciful for that coil by a big margin. I used a third order electric slope rather than the second order slope at 2.9 KHz recommended by SEAS to add an extra margin.

Luckily I had a spare driver on hand, so things are back up to snuff.

Parts are on the way to rebuild the driver, and I should have it repaired by week's end.

The speaker was driven by a Quad 909, 150 watts into 8 ohms and 250 watts into 4 ohms. The tweeter is 6 ohms. The tweeter us unlikely to have ever have been driven out of spec, but possible I suppose. I highly doubt it though. The coil was charred and the ferro fluid in the gap showed signs of over heating.

I can tell you that any receiver you could purchase is powerful enough to easily damage the speakers you have and fast.

Since you have got back into AV I suspect that that you have been playing your rig louder, and you may very well have damaged drivers especially the woofers which are most vulnerable.

So before going to the trouble of packing up that AVR check the DC resistances of all your voice coils against spec. There is a good chance you will get a nasty surprise.

TLS Guy everything you say here makes perfect sense, but there's one flaw in your reasoning. It's the fact that these speakers were perfectly fine one day, i bring home a new receiver and they're not working correctly. I would think the odds of all 5 speakers going bad in the very same day are pretty low. And even lower that it would happen to coincide exactly with a new AVR purchase. Granted they may definitely be a bit worn and maybe not quite as good as brand new but if you were able to hear what I hear you'd understand what I mean.

 

[Halon451]

I suspected the center initially because it's where a majority of the sound comes from. It wasn't until I did a close ear test on all in surround mode did I notice all we're doing the same thing. The two mains still perform very well in stereo mode. They have all the strength and clarity I know them to have.

 

[PENG]

People, 11 pages now so how about take a step back and recap. Let me do it in point form.

1) The OP has been getting "break up", "cracking" in the "higher frequency effect".

2) Up until last night, he said 2.1 stereo was fine, and thought the issue was with the center channel.

3) Then last night he did his "close ear test" and found all channels have this same issue.

4) Prior to 3), his spl meter showed that he listened to 80-85 dB when watching a movie.

5) Also prior to 3) he thought he could hear the distortions in the center channel even at 65-70 dB spl.

6) Was happy with his system until he upgraded his AVR from the Pioneer VSX-23 to the Marantz AVR-6011.

7) Based on specs and best available bench test data of similar units, the Marantz seems slightly more powerful.

First of all, logically speaking, is AVR the culprit, or something else (please read C after):

8) Since he has been saying 2.1 stereo was fine, actually sounded good, so is it possible that he's hearing the distortions when the source media is the sound tracks of movies?

9) If yes, then this need to be investigated, at least by process of elimination. If not, then his AVR, or speakers must have deteriorated during the past couple of days.

Now take a look of some facts and figures:

11) Pioneer VSX-23TH vs Marantz AVR-6011 - Both 110W, two channel driven, both appears to follow FTC rule in specifying their rated power outputs, the Pio's power consumption was listed at 400W, Marantz 650W, both uses class AB amp.

12) Speakers - The mains are same as the center, but in vertical orientation so they have 2X5.25 mid/woofers, rated impedance are 4 ohms according to S&V but 8 ohms according to Hometheaterhifi.
Hometheaterhifi actually provided their graph, you can see that the phase angle plot doesn't look bad either.

Speaker sensitivity: Mains and center - 87 dB (assume 2.83V), surrounds 85 dB.

Based on the graph from the Hometheaterhifi review, those speakers should not be considered hard to drive in small rooms.

Again, logically speaking, is power deficiency the cause?

13) If the speakers being hard to drive (which they are not) is the issue, he should have had the same issue before the AVR upgrade, so this probably cause can be eliminated.

14) If the AVR power output is the issue, again, he should have similar issue with the VSX-23TH, and the math shows that at 65-70 dB, he needs less than 1W, probably even when watching a 5.1 movie, yet he was still getting the distortion at that low spl.

15) AVR matching - The speakers are rated for 20W-120W, even if they are 4 ohm rated (we have conflicting source), there shouldn't be any issue especially he is in a small room and sits 9 ft from the mains, 5-6 ft only from the surrounds. SVS will have to confirm whether their speakers are 4 or 8 ohm nominal.

I think from the above information provided from the OP and online sources, we are left with a couple of scenarios.

A) The speakers, or some of them have deteriorated since the time he replaced the Pioneer AVR, for reasons we do not know. This seems highly unlikely.

B) The Marantz AVR is defective, a factory reset may solve setting related issue, including the impedance selection setting. It is a long shot, but no harm trying. It only takes seconds to do a reset.

C) The source media and the player - Is it possible that the AVR and speaker is just being truthful to what is fed to them? This can be proved easily by playing some know to be high quality audio in 5 channel stereo mode. If Halon is interest to try this, I suggest he put some high quality jazz and classical music on an USB and play it via the front USB port, just to rule out any electronic device external to the AVR.

D) Halon is now listening much more critical to his new AVR than he did to his old Pioneer. Close ear test is a very harsh one because from my experience, no speakers ever sound nice in this test. Go visit a high end dealer and put your ears tight against the tweeter on some $30,000 speakers and you will agree with me.

One thing for sure, those speakers are not hard to drive in a small room sitting 9 ft away even if they are 4 ohm rated. I don't know why people seem to think all 4 ohm speakers are hard to drive without considering room dimensions and sitting distance. The fact is, SVS rate them 20-120W so I am quite sure they are going to tell you the SR-6011 is more than adequate.

 

[Halon451]

PENG thanks so much for bringing it all into focus. I admit I'm even starting to feel a bit dizzy from all the research, trials, speculations, data, opinions, etc. I agree wholeheartedly with all of this. I certainly haven't ruled out an error on my part even in terms of critical listening now that I wasn't doing prior to the AVR upgrade. But I watch a lot of movies, I tend to think I would have noticed something was off if it were indeed the speakers going out. Also I did try playing source material from the BD player from my bedroom in the event the Xbox was the culprit. I certainly don't rely on audio from cable TV or even Netflix. I played sources I know to be of very good quality and mixed well. Movies I've watched plenty of times in my old system and always produced rich, dynanic and nuanced sound without any noticeable distortion at any SPL.

I'll try the multi-channel stereo test from USB. It's one I haven't done yet. Time to break out my Coltrane box set. It seems the AVR does far better pushing two channels but runs out of gas quickly when all channels are active.

I cannot reach the conclusion that my speakers are the problem here. It fails the common sense check in several ways and you have highlighted those quite well.

My thinking at this point is return it, get the Yamaha or the Pio and let that ultimately be the litmus test on whether it was the AVR or of I managed to strike that million to one odds scenario in which all my speakers went kaput at the same time. I have this option while my return window is open but it won't stay open much longer.

 

[Halon451]

Well, I'll do the whole system reset too.

I looked in the manual and could not find any info on manually setting impedance btw.. it just said use speakers of 4 - 16 ohm. So, I don't know, current sensing transformer in use here in lieu of manually setting that value? What if it detects those speakers impedance dips and keeps its output proportional to those lower Z values which may contribute to a loss of dynamics and power when running at non-peak levels? Or it doesn't respond fast enough to those changes in impedance and current draw.. is that any kind of reasonable speculation?

 

[PENG]

To be clear, I really don't know the root cause but I tried to list all of the probable ones. Give me a few minutes to figure out the impedance selection thing.

 

[Halon451]

To be clear, I really don't know the root cause but I tried to list all of the probable ones. Give me a few minutes to figure out the impedance selection thing.

Of course, lol. None of us know the root cause yet, otherwise this wouldn't be an 11-page thread.

 

[Halon451]

I was also reading the manual from my phone which is always a PITA. Easy to miss something in small print. Now that I'm at a real computer again I will look it back over at a more reasonable viewing size.

 

[Halon451]

And TLS Guy it's not my intention to simply bash Marantz or any other brand here. I'm just simply trying to seek a solution to a problem. I paid good money for this thing, I do expect it to perform as well as it can for that price. Marantz is a respectable brand. But defects happen. It may just be this particular model, it may just be my particular unit. Who knows? If it turns out conclusively that it's my speakers I'll accept that wholeheartedly and save up for replacements. But there are still things to test out before reaching that conclusion.

 

[Halon451]

So here's the answer to the impedance setting. I did miss this when reading it on my phone..


Carry out the following settings when using a speaker with an impedance of 4 – 6
Ω/ohms.
1. Press and hold the main unit’s ZONE2 SOURCE and STATUS at the same
time for at least 3 seconds.
“Video Format < PAL>” appears on the display.
2. Press DIMMER on the main unit twice.
“Sp.Imp. <8ohms>” appears on the display.
3. Press TUNER PRESET CH + or TUNER PRESET CH － on the main unit to
select the impedance.
6ohms: Select when the impedance for any of the connected speakers is
6 Ω/ohms.
4ohms: Select when the impedance for any of the connected speakers is
4 Ω/ohms.
4. Press the main unit’s STATUS to complete the setting.

It looks as if the unit defaults to 8 ohm and you have to do the above if you're running 4 or 6 ohm speakers. Mine are rated at 8 ohms, so I guess I'm a little confused by the transient impedance dips and what this means real-time, or even what is meant by the term nominal impedance. Also the graph above is only for the SBS-01, which are only on surround duty in my setup. Is there a similar graph for the SCS-01's which are my front three?

Should I try setting it to the 4 ohm setting?

 

[PENG]

It looks as if the unit defaults to 8 ohm and you have to do the above if you're running 4 or 6 ohm speakers. Mine are rated at 8 ohms, so I guess I'm a little confused by the transient impedance dips and what this means real-time, or even what is meant by the term nominal impedance. Also the graph above is only for the SBS-01, which are only on surround duty in my setup. Is there a similar graph for the SCS-01's which are my front three?

Should I try setting it to the 4 ohm setting?

No, leave it at the default 8 ohm setting in order to get the unit's rated output. Regardless of what you have previously set it to, if you do a factory reset it will be back to the default 8 ohm setting anyway.

If SVS follows IEC-60268-5, and I believe they do, nominal impedance is no more than 1.25 X the minimum impedance so to quality to be 8 ohm nominal, the minimum impedance will be 6.4 ohm or more.

Yes, that graph is for the SBS-01, but both S&V and Hometheaterhifi indicated that the impedance of the SCS-01, same as SCS-01(M) is similar to or a little higher than that of the SBS-01, so it is safe to assume the same curve for the most part.

I hope I answered your questions.

 

[TLS Guy]

No, those speakers are legitimately rated at 8 ohm. The impedance curve shows a minimum impedance of about 7 ohm,s with a maximum of 79 ohms. Most of the time the impedance is over 8 ohms. The negative phase angles coincide with the peaks of impedance pretty much. The speakers should be an easy drive.

As I said your receiver easily has enough power to make toast of those speakers.

If there is an issue with the Marantz, then that unit must be faulty. However it would pretty much have to be in the power supply is all the channels seem to be giving trouble.

My money is on speakers. If you have an old speaker around you don't want, take it apart and just look at the voice coil and how closely it is confined. Now just compare it to the power going to an incandescent light bulb and how hot even a 40 watt bulb gets. Then you understand that speakers only get away with it because most of the time we use very little power. If we don't you can see how quickly a voice coil is damaged. A 5" speaker takes very little power to start frying the insulation. Then the power output drops and the impedance drops which can damage amps

 

[Halon451]

No, leave it at the default 8 ohm setting in order to get the unit's rated output. Regardless of what you have previously set it to, if you do a factory reset it will be back to the default 8 ohm setting anyway.

If SVS follows IEC-60268-5, and I believe they do, nominal impedance is no more than 1.25 X the minimum impedance so to quality to be 8 ohm nominal, the minimum impedance will be 6.4 ohm or more.

Yes, that graph is for the SBS-01, but both S&V and Hometheaterhifi indicated that the impedance of the SCS-01, same as SCS-01(M) is similar to or a little higher than that of the SBS-01, so it is safe to assume the same curve for the most part.

I hope I answered your questions.

Yes, very much, thank you sir.

 

[Halon451]

Well then, where does this leave me. Factory reset, try to retest the sound, failing that, take it back to exchange it for something else, then if I still have problems, I will send TLS Guy a beer, lol.

 

[PENG]

Well then, where does this leave me. Factory reset, try to retest the sound, failing that, take it back to exchange it for something else, then if I still have problems, I will send TLS Guy a beer, lol.

If you are curious like me, you will continue to troubleshoot until the root cause(s) are identified but only if the return window allows. If you want to save time and/or are getting tired of this, return it and get a equivalent Yamaha. No point getting the Denon because they will be practically give you the same results, unless your Marantz is defective.

After that if you still have the problem then like you said send the guy a beer, along with the offending speakers. If he finds nothing wrong, then you may be the culprit.