Power Ratings

**Bam!** · 13 August 2004, 20:33 Friday

It`s quite simple......

A lot of companies "cheat" They have their wattage written in watts with only 2 channels driven and perfect conditions and so on.....

The truth of the matter is the Onkyo will NOT be 100 watts per channel.....

Rotel is one that is truthful...and then people think that they are underpowered `till they compare with other so called receivers that claim whatever power....

If you really want those speakers to sing....use the Pre Outs on the onkyo into an amp....then dynamics and authority...depth....clarity....soundstaging.....a ll the rest will slowly fall into place....

Basically what i am saying is while their will be sound and it might get loud....the true dynamic slam will not be there....

:P

Hope this helps!

**Glen B** · 13 August 2004, 21:46 Friday

Quit worrying. I have an Onkyo TX-DS696 receiver (100W x 5) in my HT system and with movies it plays as loud as I ever need without any signs of stress. This receiver replaced separates that consisted of a Harman-Kardon PA-5800 5-channel amp and Adcom GTP-555II preamp-surround processor. Unless your room is very large, the Onkyo TX-NR801 receiver you're interested in should suffice.

My systems: http://cgi.audioasylum.com/systems/88.html

**ThomasW** · 14 August 2004, 01:20 Saturday

The truth of the matter is the Onkyo will NOT be 100 watts per channel.....

I'll take issue with that comment. Actually Onkyo is one of the more truthful companies in this regard, and is certainly no less honest than Rotel.

The TX-NR801 has more than enough power to damage Matt's speakers if turned up. The speaker's have a max power rating of 100watts/RMS

Here an interesting review of a sister receiver from the 'Secrets' website
http://www.hometheaterhifi.com/volum...er-4-2003.html An interesting quote from the review

As for the power amplifiers, Onkyo quotes each channel as being 100 watts into 8 ohms, 20 to 20,000 Hz, with 0.08% THD, and they qualify that by saying any two channels driven. The decidedly large power supply is quoted by Onkyo as being about 1.1kVA and is coupled with 30,000µF of reserve. We'll talk about how it actually performs later in this article.

**Burke Strickland** · 14 August 2004, 05:11 Saturday

Topic One -- Amplifier Ratings:

First off, 200/7 = 28 may not seem like much, and it isn’t. But that isn’t the end of the story. Although the amplifier produced 100 watts per channel when it was tested with two channels driven according to the specification you cited, that does not mean that the total output for seven channels is necessarily limited to 200 watts total. In fact, the published specifications for the Onkyo TX-NR801 show 100 watts per channel at 8 ohms for all seven channels from 20 hz – 20,000 hz. In other words, it is nominally a 700 watt amplifier.

However, it is very seldom, if ever, that all seven channels would be driven to the maximum at the same time in real life listening, so it is not unusual for a manufacturer to run the test with fewer than all the channels driven at once. It may be (and I'm just speculating here) that, given the design of the power supply and associated circuitry, they can only achieve, say, 90 watts per channel with all seven channels driven simultaneously, so they may drive only two at a time for the test to show that each channel can actually reach the specified goal of 100 watts if called upon to do so.

At 6 ohms the wattage goes up to 130 watts per channel according to the manufacturer’s specifications Onkyo specs. They also claim dynamic headroom at 8 ohms will yield 130 watts per channels based on IHF Dynamic Headroom measurements. They appear to have made all of their amp specs using fairly widely accepted standard procedures.

OTOH, speaker wattage "ratings" are not subject to any kind of industry standard and are typically more a means of marketing differentiation between models in a given line than a true engineering measure of a speaker's operating limits. In typical listening at rational loudness levels driving a speaker of reasonable efficiency, an amp is putting out maybe one or two watts and only on peaks will it be called on for more than that, and only very briefly. Most speakers can handle that. :>)

More speakers are damaged by underpowered amps being driven to clipping due to the amp not being able to cope with the demands placed on it by the dynamics of the program material (and thus frying the speakers with waveforms they were not designed to handle) than by "overpowered" amps being turned up "too high" for a speaker "rated" for a lower wattage than the amp is capable of putting out.

Having plenty of amplifier "headroom" to handle the peaks without strain is preferable to having the amplifier "run out of steam" on the loud passages. So unless the drivers in the speakers are defective or already physically damaged, it is unlikely that in normal use the Onkyo receiver or the Rotel amps being discussed would "blow" your speakers.

Topic Two -- Selecting New Front Speakers:

Your strategy of moving the existing front main speakers to a surround position and replacing them with something more capable up front has a good precedent. That's exactly what I did in my system. :>) As it evolved, my goal was to provide a better two channel music listening experience (which is why I made a significant upgrade to the front main speakers) while also stepping up to a 7.1 configuration for movie soundtracks (and using the two former front speakers filled that requirement quite nicely).

As for recommendations for what your new front speakers should be, first question is "why do you want to replace your current front speakers?" Are there problems with clarity, tonal balance, ability to handle dynamic peaks, lack of convincing soundstage, etcetera? Are you looking for some speakers that will provide a more satisfying listening experience on two channel music or are you just tired of looking at the RT15is? :>) Or are you looking for something that might work better with the evolving THX/Dolby/DTS standards?

You might also want to consider getting a new center if the two new mains are not Polks that are voiced the same as the CS17Si. It is pretty important on movie soundtracks and for SACD/DVD-A that the front three speakers present a cohesive sound field.

Also what kind of budget do you have to work with on this? Knowing what you want to accomplish with the upgrade/change and what you are willing to spend will help in making reasonable suggestions for new speakers.

Burke

**Bam!** · 14 August 2004, 07:18 Saturday

Originally posted by ThomasW

I'll take issue with that comment. Actually Onkyo is one of the more truthful companies in this regard, and is certainly no less honest than Rotel.

The TX-NR801 has more than enough power to damage Matt's speakers if turned up. The speaker's have a max power rating of 100watts/RMS

Here an interesting review of a sister receiver from the 'Secrets' website
http://www.hometheaterhifi.com/volum...er-4-2003.html An interesting quote from the review

Hi Thomas!

While I wasn`t thinkin`anyone would take issue with that comment....I am talkin`from personal experience with Onkyo to Rotel......the supposed wattage of Onkyo was rated as the same as Rotel.......but the difference in insane between the two....

That`s all I meant.....

**Shane Martin** · 14 August 2004, 08:00 Saturday

First off, Ignore the power handling of your speakers. My friend feeds 350 watter per channel to his 8 year old Polks w/o a strain. More power is better than less power.

Second, Onkyo is just now announcing new receivers. The 801 will be replaced soon. Given the new features that are starting to be added, I'd wait(if you can). If you can't Then we can talk about what you need/want and how much you can afford.

Third, The Onkyo 901 was tested by S&V a while back and did not produce its rated power for all channels. It did produce 137 wpc for 2 channels though. I'll dig up the true numbers at a later date if need be.

**mj1856** · 14 August 2004, 17:30 Saturday

Thanks for the great advice so far. I'm still a bit confused though. Sorry for being such a newbie in this department.

So on one side of the argument, I'm not getting enough power to drive the spakers to their fullest potential.

On the other side, I could get too much power and damage my speakers. I'm assuming that could only happen if I turned the volume up very loud. I read in that review that you could set a max volume level. That could be the answer there.

So is the 901 a safe choice as well then? It's specs say 110W. I don't know about doing that since my speakers are rated at 100W. But perhaps that doesn't matter if they're not ever going to get that much power because of how it gets divided up?

Anything's going to be better than my current system. I did buy the Polk speakers myself, but a friend gave me his old receiver, so I've just been making due. It's a Kenwood VR-309. Specs here: http://tinyurl.com/47g58 The Onkyo is going to kick it's butt without a doubt.

My reason for the Onkyo 801/900/901 is that they've got great reviews, and I love the idea of the streaming internet radio and MP3 support. I haven't been able to tell much difference between the three models other than the wattage. I'd rather not get the latest model being released, but a good older model or even used would be fine.

As far as speakers go - Yes, I had also considered replacing the center. The CS175i is the lowest end of the Polk center channels. For fronts, I will probably go to floor-standing speakers. Perhaps the Polk R40's would work well? For the center, perhaps the CSi30? Chances are I'll being buying most of this off eBay, as my budget is about $1000-$1500 for receiver and front & speakers. I still want to get the most for my money though, so I'm open to suggestions.

As far as what I really want to get out of the new system - better 2-channel audio is part of it, and also just better overall movie experience. I want something that I can put in CD's for dailiy listening withough having to strain to hear the mid-range. And I also want that immersement you can only get from full surround sound. Like the plane crash scene in Cast Away - I've gotta hear that in it's fully glory.

Thanks for the help.
-Matt

**ThomasW** · 15 August 2004, 00:36 Sunday

Go for the highest power receiver you can afford.

Regarding speakers if you can afford the Polk LSi series get those. They use world class tweeter (Vifa XT-25, aka the ring radiator). The LSi9 for example is a great little speaker. As long as you use a sub you don't need large floorstanding mains. If these speakers aren't in your current budget, they're worth saving your money to get. They are in a different league from the other offerings from Polk.

**caleb** · 15 August 2004, 01:27 Sunday

Output v's speaker qualities

It is my experience that just looking at what your receiver puts out into 8 ohms is not enough.

Many speakers go down as low as 2 ohms depending on the frequency curve.

You must also look at the power output into 4 and then 2 ohms.

If you receiver has sufficient reserves it should approximately double it output into 4 ohms and then double again into 2 ohms.

This is also a good test of the amplifiers power.

**caleb** · 15 August 2004, 01:31 Sunday

Amp v/s speaker compatability

I agree 100% with your comment that the worst combination is a low power output rather than a higher one within reason.

When the amp clips, it is effectively sending a DC current to the speaker, and they are not designed to handle DC current.

So better a higher power amp so you don't get this effect.

**aud19** · 15 August 2004, 14:01 Sunday

Don't worry about overpowering your speakers with too big of an amp. If you are even close to playing at levels that would harm the speaker, one it would be rediculously loud, like "you wouldn't be able to be in the same room loud" and two, they would likely be distorting to a painful level. More power is almost always better as it allows your system to fully utilize it for dynamic peaks in music and movies.

If one of your main goals is to have better 2-channel I'd personally look at the recievers from Nad or Rotel. Both offer generally better power (although their rated power may be listed lower) with stronger power supply's and generally better construction and sound quality IMO. Rotel tends to be more neutral, Nad warmer... Both are more musical than the "mainstream" brands IMO.

As for internet radio... it's not that great quality. It might sound OK coming out of small PC speakers but amplified through decent equipment... most of it will sound pretty tinny etc. If you really want to stream audio from the internet or off of your PC, run some audio cables from your PC to your receiver or build a HTPC. There's also numerous wireless equipment solutions as well for just audio as well as video and data.

Jason

**Danbry39** · 15 August 2004, 15:56 Sunday

First off, no disrespect intended, but Onkyo doesn't rate their amps as fairly as Rotel. Here's a link to lab tests to verify this. The Onkyo 901, rated at 110 watts/channel actually is tested at 50 watts/channel with five channels driven simultaneously. The Rotel, rated at 100 watts per channel actually tests at 106 watts/channel under the same test conditions. Therefore, the Onkyo which has a published watts/channel rating above the Rotel, actually has less than half with five channels driven simultaneously.

That said, the additional power available on the Rotel will only result in a three decibel increase in the sound pressure level. This is very significantly less than a doubling of how loud you perceive the sound. Won't go into all the details, but actually raising the sound to what you hear as twice as loud wouldn't be achieved by moving from, let's say a 50 watt/channel amp to a 100 watt/channel amp. It would be more like moving from a 50 watt/channel amp to a 450 watt/channel amp.

Also, keep in mind that, at normal levels, most systems are using only a few watts per channel. When a speaker is rated at, for example, 90 decibels sensitivity, that means it only takes a single watt of power to drive that speaker to 90 decibels at one meter's distance. Of course, the further you move away from the speaker, the more juice you'll need to achieve this level.

What I'd do is check out the sensitivity and resistence of the speakers and make sure the Onkyo can handle the load. I'd also check out other receivers for preference.

As stated by Burke, you will rarely, if ever, encounter situations where all five channels draw on the amp at full power simultaneously.

As already noted, overpowering is better than underpowering. It is much more commonplace for speakers to be damaged by overdrawing on an underpowered amp causing distortion and clipping.

**Bam!** · 15 August 2004, 19:00 Sunday

Originally posted by Danbry39

First off, no disrespect intended, but Onkyo doesn't rate their amps as fairly as Rotel. Here's a link to lab tests to verify this. The Onkyo 901, rated at 110 watts/channel actually is tested at 50 watts/channel with five channels driven simultaneously. The Rotel, rated at 100 watts per channel actually tests at 106 watts/channel under the same test conditions. Therefore, the Onkyo which has a published watts/channel rating above the Rotel, actually has less than half with five channels driven simultaneously.

That said, the additional power available on the Rotel will only result in a three decibel increase in the sound pressure level. This is very significantly less than a doubling of how loud you perceive the sound. Won't go into all the details, but actually raising the sound to what you hear as twice as loud wouldn't be achieved by moving from, let's say a 50 watt/channel amp to a 100 watt/channel amp. It would be more like moving from a 50 watt/channel amp to a 450 watt/channel amp.

Also, keep in mind that, at normal levels, most systems are using only a few watts per channel. When a speaker is rated at, for example, 90 decibels sensitivity, that means it only takes a single watt of power to drive that speaker to 90 decibels at one meter's distance. Of course, the further you move away from the speaker, the more juice you'll need to achieve this level.

What I'd do is check out the sensitivity and resistence of the speakers and make sure the Onkyo can handle the load. I'd also check out other receivers for preference.

As stated by Burke, you will rarely, if ever, encounter situations where all five channels draw on the amp at full power simultaneously.

As already noted, overpowering is better than underpowering. It is much more commonplace for speakers to be damaged by overdrawing on an underpowered amp causing distortion and clipping.

:agree:

**mj1856** · 16 August 2004, 17:14 Monday

Originally posted by Danbry39

What I'd do is check out the sensitivity and resistence of the speakers and make sure the Onkyo can handle the load.

Well, my speakers are all rated at 100W, 89db, 8 ohm. I'm not sure how to compare that against the specs of the receivers.

I've started looking at other brands. Thanks for the link to that chart.

If anyone has any other recommendations on a cheap (under $600) 7.1 receiver, please let me know.

Thanks,
Matt

**Danbry39** · 16 August 2004, 17:18 Monday

The Onkyos mentioned will drive those speakers easily. If you end up getting the LSi's, I think they're 4 ohm speakers and will need an amp that can deliver that type of current, which those Onkyos are rated to do.

**mj1856** · 16 August 2004, 17:27 Monday

Oh, I should note that I stopped by a few retail stores to see what is out there.

Ultimate Electronics had a Denon model that looked ok, but the salesman was an idiot and couldn't tell me too much about it.

I also Stopped by Jerry's. They had knowledgeable staff, but not much selection in my price range. They recommended a Sony STR-DA3000ES for $1000. I found it online for about $600. Any opinions on this one?

I still want to go by Circut City and a few others. Chances are that I'll end up buying online, but still want to check them out.

Thanks,
Matt

**aud19** · 16 August 2004, 17:29 Monday

I've had good luck with Yamaha, HK and Denon though you'll likely run in to the same problem of overzealous power ratings with many "mainstream" companies. HK has a pretty good reputation for honest power ratings.

Basically with your 4ohm Polk's you want as good of amplification as you can afford. try to narrow it down to a few receivers and check the specs on each ones power supply. The bigger/better the power supply the more likely it will be able to supply adequate power. As mentioned the extra power mostly comes in to play at dynamic peaks. But HK's 75W is probably pretty comparable to say Onkyo's 100W etc so you can only use power ratings as a loose guide. At this price don't even worry about over powering your speakers, it won't happen.

Jason

**mj1856** · 16 August 2004, 18:00 Monday

Originally posted by Danbry39

If you end up getting the LSi's, I think they're 4 ohm speakers and will need an amp that can deliver that type of current, which those Onkyos are rated to do.

Originally posted by aud19

Basically with your 4ohm Polk's...

They LSi's are out of my price range. I'll likely be sticking with 8 ohm speakers. Probably the Polk R40 or R50 (150W, 90db, 8ohm). Unless someone has a better suggestion.

Thanks,
-Matt

**aud19** · 16 August 2004, 18:09 Monday

Still, even with 8ohm speakers, stick with a good power supply. It's usually the heavier machine

Jason

**Danbry39** · 16 August 2004, 20:31 Monday

As far as speakers, I'm a believer in on-line speaker companies for great value/sound quality. If you give a price range, I can point you in the direction of some great speakers such as Rockets, ACI's (my speakers), Ascend, Axioms, etc. depending on your tastes and asthetics as far as how you'd like them to look.

Jason is right about getting the best power supply you can...now. An alternative would be to get a receiver which has preouts so that, if needed in the future, you can add on a power amp to really make your speakers sing. When I had Klipsch speakers, which are very efficient, I still bought a power amp that delivers over 150 watts/channel. That way, when I bought my next set of speakers, rated at only 86 decibels sensitivity, I still had plenty of power in reserve.

Another receiver you might consider are the new Panasonics with the digital amps. You can get them online for under $400 easily. A new one is about to be released. These receivers have been drawing raves thus far, although I haven't personally auditioned one. Also, companies like Denon, Onkyo, and Harmon Kardon come out with new models quite frequently. When they do, sales of the old stuff can be quite dramatic...so always keep an eye open. When a friend was looking last May, we found a Harman Kardon 7200 for $786 or so when the previous MSRP was something to the tune of 2K (although I'm not sure if the msrp figure is quite right).

By the way, I gave my eldest daughter my old Onkyo receiver and bought her Polk speakers and it sounds very nice, but, again, the online only route can have a drastic impact on what you get for the money. No dealer/distributer costs, etc. Outstanding customer service too.

**ajpoe** · 19 August 2004, 11:33 Thursday

I have the Onkyo TX-SR800, the same model just a year older. I have a full Paradigm Studio v3 (60s & 470s) set up for HT. I purchased the Rotel 1075 and it was far more powerful than the TX-SR800 and I am very happy with the purchase. I'm just using the Onkyo as the processor for now and to run Zone 2. With the 1075 there is no stress whatsoever even at high volumes.

ajpoe

**mj1856** · 19 August 2004, 11:54 Thursday

Question - If I did go with an external amp, would I be okay with just getting a two-channel amp for the front mains and driving the center and surrounds off of the receiver?

I'm just curious if that frees up power for the surrounds by not having to drive the fronts. Multi-channel amps can get quite pricey, but I can find some good prices on two-channel.

What do you think, would this work? Or would it make them sound too different from eachother?

Thanks
-Matt

BTW - I've finally decided on speakers. Sticking with Polk Audio to match my system, I'm going for either R50's or RTi70's for the fronts, and either the CS245i or CSi30 for the center. Anyone know where I can get them cheap? Or used?

**David Meek** · 19 August 2004, 12:39 Thursday

Matt, lots of people do this. Trust me, you won't be the first.

As far as matching sonically, it'll be very tough to get a perfect match. So, it becomes an exercise of "is it close enough for me" and only you can answer that.

**ajpoe** · 19 August 2004, 14:26 Thursday

I'd say that if you were to get a 2 channel amp for mains and ran the surrounds and center off the Onkyo, it would free up some of the load on the receiver... but, the main thing here would be if you got a nice 2 channel amp like the Rotel 1070 (probably plenty for the polks) or 1080 it woud really sing for 2 channel music. If you're looking for used equipment, I've got good deals from both Audiogon and Audioweb.

ajpoe

**Paul H** · 19 August 2004, 20:58 Thursday

Originally posted by mj1856

Question - If I did go with an external amp, would I be okay with just getting a two-channel amp for the front mains and driving the center and surrounds off of the receiver?

I'm just curious if that frees up power for the surrounds by not having to drive the fronts. Multi-channel amps can get quite pricey, but I can find some good prices on two-channel.

What do you think, would this work? Or would it make them sound too different from eachother?

Thanks
-Matt

I just recently added a 2-channel amp to my receiver to power the two mains, and would heartily recommend it. Most all low and mid-fi receivers run their separate channels from shared power supplies (I know there are exceptions) and benefit from the 2-channel amp taking a major part of the power load. I can't say that I've noticed tonal matching being a problem at all, although I'm not nearly as picky about HT sound as 2-channel.

Paul

Power Ratings

Power Ratings

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