Axiom Home Page Forums General Discussion Home Theater Amp power comparison

Hello everyone,

I have a question related to comparing amps with different wpc ratings. Here's the scenario:

i have the following speakers:

fronts: M22
center: VP150
rears: M3
sub: EP125

my amp is integrated, it's a Denon 1602, rated at 70 wpc. Before purchasing it, I compared it to the Denon 1802, rated at 80 wpc. I personally did not notice any difference that was worth the price difference, but this was in the store and only on 2 channel audio, on Paradigm Monitor 7's.

I figure 10 watts won't really make a difference. However, how about 30 or 40 watts? would a 100 wpc, or 115 wpc amp make a noticeable difference? Will it really increase bass output? After listening to a lot of music and watching a lot of movies this weekend, I realized that at high volumes, the bass is lacking, and it starts to distort.

So, if anyone has done any comparisons of amps that have similar power to mine and to amps that have, say 100-125 wpc, I'd like to hear your comments and observations.

thanks!

If it's a Denon it's not losing power or causing the Distortion unless your full trottle on the amp.
It's the speakers

All seriuosness though,
I had a Denon 900 and a 1400 I have a HK 510 now only reason is somebody had a buzz in a HK65 I bought it still under warranty called you and after a few Phone calls they realized it was the Amp now I have a 510 as replacement but, if it wasn't for 5.1 I'd take my Denons back. it has the same power ratings as the 900 Denon but the Denon is louder at the same volume levels. Although I will not go over 1/2 volume so I cannot tell if the Denon loses power above this but after alot of reviews I it is one of the best integrateds.
As far as I'm concerned if you have to turn your amp up over 1/2 then you need a more powerful one. Especially if watching movies.

doretyp,

the amp pushes the speakers well, just not at very high volume levels. What I was asking was if anyone has compared an amp similar to 70wpc with an amp at about 115wpc at very high volumes, if it made any real difference, for instance, in more bass and capable of handling large blasts of sounds. This is called dynamic headroom, I believe.

Thanks for your input, though. I was thinking H K but the price is way too high for me. This Denon does sound very good.

Yeh well I'd spend my money on Denon over HK any day.
I believe and stand to be corrected on this although I am 95% sure I am right, Dynamic headroom would be if you are listening to your sound system at say 50% and there is a explosion the volume inceases drastically eveen though you are not turning up the dial it still pushes the wattage out. The head room part is that you have enough wattage there that the amp doess not distort when it it produces these levels.
I can see how if you turn up the volume until you get distortion but I do not think it has the same effect as a sudden burst of energy.
I beleive that a 70 wpc Denon will not clip as easily as say a 70wpc kenwood even though the wattage is the same I will bet the Kenwood will clip way beore the Denon. But hen the Denon is a high current quality and the Kenwood is well Kenwood.
Then again a 70wpc Carver Cinema Grand will ick volumes galore over the Denon but at $3000 more.
I know the Denon you have is alot better than most amps your gonna buy in the 70 - 120 watt area unless then of course you can buy a Sunfire
PS stay with the Denon over the HK in terms of attage the Denon900 I had was 70wpc and the HK 510 I have now the Denon is was louder at the same 50% level

Ravi, speaker sensitivities are typically rated in db of loudness when driven by 1 watt and a typical in room sensitivity would be about 90 db. When driven by more than 1 watt, a dbW figure is used to show increasing loudness. For example, 70W=18.45 dbW, 80W=19dbW, 100W=20dbW, 140W=21.45dbW. These figures are added to the loudness at 1 watt, e.g. at 70W output level is 108.45db, at 100W it's 110db. Therefore the difference in loudness between 70 and 100 watts is only 1.55db out of an almost deafening 110db level. Doubling the power to 140 watts results in an increase of only 3db. To double the loudness level requires an increase of 10db, which in this case would require 700 watts. The point is that the difference in volume capabilities among typical amps and receivers is quite small and shouldn't be a major factor in the purchasing decision.

Incidentally, the setting of the volume control necessary to achieve a certain degree of loudness has nothing to do with how powerful the amplifier is. It's entirely possible for a more powerful amp to require a 1 o'clock setting for the same volume that a less powerful amp gets at 11 o'clock.

JohnK

that was informative, though I knew that already
just to continue things, I wasn't really referring to its inability to make the speakers play loudly. I was more concerned about the distortion it would start to cause if the volume was turned up very high. For example, my amp goes -60 to +10. Say I am watching the Fast and the Furious at -15. It sounds great when they're talking or whatnot, but then when the cars are giving out a huge sound, the amp needs to push out a whole lot more watts, and it distorts a little. If I put the volume down, then the distortion stops. Therefore, it's not the source causing this. I was wondering if, say, the Denon 3802 which has something like 110 wpc would distort less at the same volume level of output in dB (not the position on the volume dial) than my 1602 at 70 wpc. And, if so, how much less would it distort.

As you know Ravi, the distortion at certain very high volume moments may be due to the speakers, the amp, or both. I recall that you've previously commented that you run all your speakers at"large". Have you experimented with setting them to "small" to see if the distorted moments improve? Lessening the load on the speakers is one of the advantages of the "small" setting.

If it's mostly the amp then it's possible that if the problem is in the narrow power range where the lower power amp is distorting badly yet the higher power amp wouldn't be,that more power would help. If possible, borrow a much higher powered amp to check this .

Ravi -

I believe you are correct when referring to "dynamic headroom" as the ability for the amp to product large increases in volume for relatively short bursts.

The reading that I have done suggests that the "dynamics" of dynamic headroom are different for home theater vs. music (usual argument is that home theater is the more demanding as it requires longer, sustained peaks).

As many reviewers point out, separate components are typically designed to a higher standard. That's why a 60W "separate" amp will outperform a 60W AV receiver. I suspect a large part of the increased performance of separates has to do with its ability to generate dynamic headroom without distortion.

So, to your question about distortion at sonic peaks in program source material: At the same volume level, I suspect that the difference between two AV receivers (one at 75W, one at 100W, for example) would be almost exclusivley explained by the amps' dynamic headroom.

Few manufacturers dare report dynamic headroom, and I have never seen a reviewer attempt a test to measure it (if indeed it can be "measured"). Yamaha is reporting it (see for example, http://www.yamaha.com/cgi-win/webcgi.exe/Specs/?gAVR00010RX-V730), but I have no basis to know if the spec they report is good or not (they claim 1.2dB of dynamic headroom at 8 ohms). This doesn't seem like much, but I suspect, given Yamaha's good reputation, many AV receivers would fail to achieve the same dB increase.

The other interesting number would be how long an amp could sustain its dynamic headroom spec.

I have tried it at small and it does reduce the distortion. However, I am not a fan of the way it sounds on small because my receiver cuts off at 80, whereas the M22's can play perfectly down to 50, and somewhat down to 40.

Cgilker

yes, I agree with that. I hear that Le Amp by nOrh, rated at 100wpc, sounds stronger than most regular integrateds. I just might buy those, or equivalents, when I have thousands of dollars lying around (yeah, right...) for an audio upgrade

Ravi, I'm a bit curious about your impression of the "small" setting, since, if anything, the performance at 40-80hz should be a bit better with the sub handling more of it. When you did that did you turn the crossover on the sub all the way up so as to minimize interference with the 80hz crossover on the receiver?

I always have the crossover set to the maximum so it doesn't interfere with the setting.

having two speakers set at small and a sub sounds just fine in terms of getting the whole range of sound, but I much prefer the soundstage and imaging of just two speakers, so to get as much bass as possible, i set them to large. For just two channel listening, I likely would have been better off with M60's or M80's, but they are way over my budget. Perhaps next year I will buy a pair of towers, move the M22's to the back, and sell my M3's.

Hi all,

Lots of good advice from JohnK about the relationship of perceived loudness levels and the huge increase in electrical watts required to cause a small subjective increase in loudness.

There is no universal standard for measuring dynamic headroom. When it is quoted or measured, it's in milliseconds (several thousandths of a second) which is sort of relevant, but it's better to try and judge an amp's output capabilities by the robustness of its power supply: How big are the storage capacitors, and the power transformer?

Look through the vent holes on the top for the round capacitors (usually near the transformer). If they're big and fat--the size of a normal soup can (unlikely in all but a few expensive receivers)--and the transfomer is large and heavy, you can assume the receiver's power supply is robust and able to supply sudden demands for output power (an explosion in a HT war move, for example). The capacitors store electrical energy. If they're puny, and an explosion in a movie comes along, the power supply may "sag" and be unable to meet the demands of the output stage, causing distortion.

You can even judge power-supply quality by the physical weight of the receiver (assuming the manufacturer didn't hide a brick inside to trick naive consumers...ha, ha).

It's too complex and long-winded to go into here, but I'm preparing an article on power output standards in multichannel HT receivers. Output for most brands is quoted, at best, in the stereo mode, with only two channels driven. When five channels are driven, the power output often is dramatically reduced, to a fraction of its stereo capabilities. And it's often quoted at just one frequency--1 kHz, rather than over the full frequency range of hearing (20 Hz - 20 kHz). All this is very misleading and confusing for consumers. Standards have sharply declined, partly because manufacturers are trying to jam five or more power amps onto one chassis and sell it at $500 or less while giving the impression that the receiver can output 5 channels at 80 or 100 watts per channel simultaneously. And it can't.

Well, that ought to stir things up....you'll read more when my separate web site, The AudioLofft Report, gets up and running.

Regards,

In reply to:

---

However, I am not a fan of the way it sounds on small because my receiver cuts off at 80, whereas the M22's can play perfectly down to 50, and somewhat down to 40.

---

Hmm, Axiom's specs say that the -3db point for the M22 is 60Hz, and that it's down 9db at 50Hz. I would think an 80Hz crossover would be just right. Keep in mind the crossover point is not a "brick-wall"; your M22 would still be getting some bass below 80hz, it will just be rolled off as you get lower. A common guideline is that a speaker should be capable of producing at least some bass a full octave below the crossover point (ie 40Hz). If you don't like the sound when using the crossover, it may mean that you need to better integrate/calibrate the sub for your system, or it could be that your sub produces too much distortion.

Hey Alan,

OK, can you give us an idea as to what the launch date is for THE AUDIOLOFFT REPORT? While I have your ear or eyes , what is your impression of the NAD T761?

Thanks,

CAV104

Jim,

I'm not Alan, but I wouldn't buy NAD over Denon.. NAD is overpriced, if you ask me. There's also the Outlaw 1050 out there, it's a 6.1, i'm sure you've heard of it.

If you have been reading about me thinking my Denon didn't sound too good at loud volumes, well.. I set all my speakers back to small, and fiddled with placement, as well as sub placement, and it sounds much better. I'm also using a pair of your cables aged for 13 months in an oak filled barrel with ginseng root and a goat tripe. They're absolutely EXQUISITE if you add a pinch of salt and a squirt of lemon from the south east of India.

For the second time today i agree with RAvi. NAD used to be quite good but now i find they are overpriced and running on reputation.
I looked at the Outlaws and was impressed but the Onkyo DS797 had me equally impressed, came highly recommended and i got it for an absolute steal from a recommended local vendor who did his buddy a favor and 'helped' me with the price.
You would never believe just how much those electronics get marked up upon resale!!

chesseroo

I'm glad you agree with me..

it's true, these audio electronics get marked up substantially, because poeple will buy them.

The Denon 1602 MSRP is 770$ CAN. The store where I buy my electronics (Dumoulin / Audiotronic) had it on sale for 648$. I went to one store, I tried talking the guy down, he laughed at me and said there's NO WAY they can make a profit and sell it 648, so he refused to lower his price.. Then I went to Dumoulin, and I talked the guy down to 539$!!! With it I bought their 5 year warranty with yearly checkups / cleaning, and with tax (which is murder in Quebec), the total was 699.99$
that's 70$ less than the MSRP. If I would have paid 770 plus 75$ for the extended warranty plus tax it would have cost 973$. And I bet they STILL made a good profit off me.

The Onkyo 797 has a US MSRP at $1000 which is of course about $1650 Cdn. THe best price i found in canada so far was $1899!!
I got the receiver for $1500 but i can't say where although he is an authorized dealer. He still made a bit of cash off me but i'm sure not alot.
I could have got one via ebay brand new for about $1650-1700 after tax and customs.
Even this whole cable issue. I talked to a guy about getting 12ga cable for a buck a foot and he sold me his 10ga for the same even though it was listed at $1.50.
Since when do people get 33% off the retail price when its not at Walmart?
Ya, serious markup. I can't imagine how people pay 8 bucks a foot for cable when it probly costs about ten cents a foot to make.
I guess it must be all that R&D cuz i know for sure i'm THRILLED with the Axiom price:performance:quality!!

Hello chesseroo & Ravi

Thanks for your input guys. Cheeseroo, what speakers are you driving with the Onkyo 797?

Thanks,

CAV104

Right now i'm using the M60s in Boston Cherry. Just got em a week ago.
I also wanted to audition the M22s so they are here as well, but going back.
In about a month i plan on rounding out the system with the QS8 surrounds, VP150 centre and EP350 sub.
In a week i'll be updating the Denon cd player to a Panasonic CV52 dvd or a Toshiba equivalent.

Hey chesseroo,

What is your impression of the 797 matched with the 60s?

Thanks,

CAV104