how much power

I do not have a good grip on amps. But i keep hearing about more power and more current !

I don't listen to music very loud... may be 75db at the most. The roomsize is 11 x 15. My speakers are Vienna Acoustics, Haydn Grand (4 ohm). Receiver is Denon 3311ci.

My question is really if i need need anything more than say 50 watts per channel ? Why ?

Vienna Acoustics recommends a minimum of 25 watts for this 89db sensitive speaker. You should be fine.
If you find the amp is clipping/distorting at higher volumes or the bass is loose sounding, you may benefit from an amp with more current, not necessarily more watts.

If you like what you hear you are fine.
I think one of the biggest misconceptions about power (especially when someone is just starting out in this hobby) is that going from 50 watts to 100 watts, while being twice the power will be twice the volume. NOT TRUE. The truth is, to achieve twice the volume you need "10" times the power. That means you need a jump from 50 to 500 watts to play twice as loud.

That was pretty much black and white. Where things get a little gray: Why do some 50 watt amps sound better/louder that some 100 watt amps? This is where the current, power supply, characteristics of a particular speaker, etc come into play. Example: Your speakers are rated at 4 ohm. That's an "average" the manufacturer has given it. It may be 2 ohms at some frequencies and 10 or more at others. Ahendler and I both use Magnepan 3.6's. They are rated at 4 ohms and 85 db but may actually be easier to drive than your Viennas at 89 db (don't know, haven't seen your impedance graph) due to the Maggies being very flat (impedance wise) with no dips demanding more current at a moments notice.

"My question is really if i need need anything more than say 50 watts per channel ? Why ?"

If it sounds like the music is straining, maybe more power would help. Could be the Denon is having a little trouble with the 4 ohm load and your speakers want more current than the Denon can supply easily.

Are you happy with the sound now? What you have going for you is the smaller size room and 75 db listening levels. If I was going to hazard a guess (and it's a hazard), If your speakers have some bad dips in their impedance combined with tough phase angles, you might get a more relaxed sound with an amp that can "easily" supply the current your speaker demands.

Go by how it sounds to "your" ears.

Something else to consider is that the Denon receiver is rated for
a minimum impedance of 6 ohms, and the speakers are 4 ohms.
I’m not sure if this would be a problem with just a pair of speakers,
but running a full surround system, I think it could be a problem.
esp. with your reasonably efficient speakers, it's the quality, not the quantity of power they're fed. the weak point of most avrs (incl. denon) is the amp section--one of the most significant night-and-day improvements i've made was bypassing the amps in my denon avr and using an external amp to power my front speakers. even a modest 60w adcom amp sounded much better than the (purported) 130w amp section of my denon.
If the amp is rated for 6Ohms minimum, than it will not have enough current for 4 Ohm speaker. Not only the output power is jeopardised because of mismatched impedance and lack of current, but also the remaining power is jeopardised by heat.
If OP gets half of rated power to the speaker, consider that as a best case scenario where the worst is fried amp even on moderate 75dB volumes.

Conserning Onemug's statement in general it's true that 50W and 100W will have a slight difference in SPL but in this particular case it's a substantial difference.

So Roxito,
You can have amp as low as 50Wpc, but it should be rated stable for 4Ohm load or preferably lower.
You just need better amp, not necessarily more powerful but probably higher current with more sophisticated power supply. Vienna are good speakers and deserve good amplification.
Impedance being fairly flat is only one key to Maggies being an 'easy' load.
Second is line source. They couple very 'efficiently' into a room and don't drop level as rapidly as 'box' speakers of conventional design. The difference is not subtle
Third is phase. They don't have any of the wacky reactive behavior of some speakers which are at higher sensitivity.

Than again. some amps while measuring well into a resistor, do poorly with some types of reactive that capacitive or inductive.

To properly characterize a speaker as good/bad from the electrical load aspect, you need the phase data as well. Look up ANY of the stereophile speaker tests and they'll have such data. Any speaker with a big dip in impedance AND a high phase angle will be 'red flagged'. The warning will include advice to 'get thee a good amp'.
What is the minimum amout of current an amp has to deliver, to be considered a 'high current' amp?
Rok2id, the amount of specified current isn't important. A stability to the certain load is. An amplifier that delivers 60W onto 4Ohms presumed to have sufficient current to drive 4Ohm speakers.

my amp is rated at 150 wpc and 45 amps per channel. my speakers are 88db 4 ohm. Is this a good match? Smallish room and modertae levels, so I have no complaints, just curious.
Unless there is some very ugly quirk in the impedance curve/phase profile of the Vienna speakers, I'd find it hard to believe that the Denon's 125 wpc amp section will not comfortably drive them to levels well north of 75 db in an 11 x 15 room. As to available current and stability into the load, I seriously doubt that you have an issue with either.

It is certainly true that SQ may vary from power amp to power amp. Designs differ and different amps each interact in their own way with any given speaker's load, but that's a different kettle of fish. You may well prefer a different amp, but I highly doubt that you NEED one to drive your speakers to your desired levels.

Whatever else may be going on here, this set-up does not appear remotely underpowered to me.

Roxito, good thread. I am currently researching the same scenario with my bedroom system, which consists of a Yamaha RX-V1800 receiver driving a set of Monitor Audio Silver 9i towers. The bedroom is the master, and not small, at 14 by 16 feet. I think the speakers are rated 6 ohm, but may drop lower than that. The 1800 is rated at 130wpc into two channels. But it seems that if I crank the volume even to what I would consider a moderate level, the sound gets "glassy", loses clarity, and generally gets somewhat unpleasant to listen to. Could be increased room reflections, but I think there is more to it than that. Could also be speaker cables, which are Goertz MI-2 Veracity.
I'm with you, just didn't want to get into all the advantages of Magnepans and answer the OP's question as to why "he" "may" need more than 50 watts. If I listened to the Left Brain crowd, I would have never tried a Cary 805 (50/70 watt SET) on my Maggies. That would have been a loss.
No problemo. I used a Kenwood integrated for a while...with MG-1s. This was quite a while ago.

As to 150 watts and 45 amps? That's about 3.3 volts. Clearly something doesn't add up.
My panels are fused at 4 amps for mid/tweet. Figure 8 amps full tilt for the whole enchilada. Why would I need 45 amps? My Ice amps have some wacky spec like that which is IMO, nearly meaningless.

I would suggest that some scheme like this....linked, is a good place to start in any chat about amplifier REAL power into REAL loads.
'As to 150 watts and 45 amps? That's about 3.3 volts. Clearly something doesn't add up.
My panels are fused at 4 amps for mid/tweet. Figure 8 amps full tilt for the whole enchilada. Why would I need 45 amps?'

Well what does it all mean? Some very reputable companies always list this spec. Parasound and Harman Kardon come to mind. The bigger HK list 100 amps and the parasounds 60 amps. I have read some gurus that say amps are not even important. So I guess it's an audiophile thingy, i.e No answer. BTW, the link and the cube graphs etc.... are very similar to the method used to test amps in the Audio Critic. Better be careful. :)
Personally, I guess I'd fall on the 'amps is red herring' side of the fence.
Pass is the only amp manufacturer who lists VOLTS and watts. I also suspect his amps are nearly stable enough to either weld or charge batteries.
Audio Critic? I'll go have a look.
One thing to consider is Safe Operating Range of any semiconductor device. A power transistor, even with bigtime heat sinking can only take so much.
This is a wiki about SOR and explains it better than I can. To raise the stakes, multipe devices are paralleled.

As near as I can figger', discussions like these really end up being about power supply.....mentioned or not.
Magfan, Rok2id,
45 amps is peak current that has nothing to do with operating continuous collector voltage of amplifier.
Continuous current would probably be in the range of 1...2 amps.
What is necessary for amplifier to deliver the same power onto the 4Ohm load vs. 8Ohms is to double the current and not on peak or transient bases but on continous.
Not all amps are capable to weld but there are some.
'What is necessary for amplifier to deliver the same power onto the 4Ohm load vs. 8Ohms is to double the current and not on peak or transient bases but on continous.'

Then, would it be accurate to say that a true 'high current' amp will double the current (continous) when the load is halved?
What, if anything, does this say about the quality of an amp? I am trying to decide between the Harman Kardon HK 990 and the Parasound New Classic 2250. The HK doubles, the Parasound does not, but it's watts per channel is greater into 4 & 8 than the HK. The parasound list 45 amps and the HK 100amps. From just this information, can any conclusions be drawn as to which is the better quality amp?
BTW, thanks for your answer.
whichever you prefer. I wouldn't let an amps amps decide anything for me.

Someone needs to tell me how an amp can peak 45 amps and NOT drag the powersupply down to a low voltage, regulation or not. Even if you dump a huge capacitor bank, you than must contend with 200 watt transistors above designed limits.

power is watts, = volts x amps

Unless we are going back to the days of IPP (instant peak power) a scheme whereby an amp with a door bell size transformer can be said to have 500 watts.

As for doubling up? This is 'the law' for panel speaker users, like myself. howver, I'd rather have an amp with 400 watts at 4 or 8 ohms than an amp which doubles up from 100watts @8.

I think NAD may be on to something with continuous ratings being the same across impedance, but an ever increasing dynamic power as impedance drops. No mention ever of 'amps'.

Are you familiar with the unique design of the HK 990?

The unit's preamp section offers the kind of DSP that you would usually find only in a multi-channel AVR or pre-pro. (It has ADC, DAC, digital bass management, digital room EQ, etc.) Personally, I think it's an incredibly good idea, but it's definitely not the usual "audiophile approved" approach. I'd love to endorse it, but unfortunately, it's well nigh impossible to find one to audition and I've never heard one. However, if you listen primarily to digital sources, this thing has unique capabilities among 2 channel amps.

My point is that, the HK 990's power amp section, while a highly regarded design (see below) isn't really what PRIMARILY distinguishes this unit from the Parasound (or anything else, really).

That power amp section itself follows the Matti Otala Citation design principles established decades ago. Many people (me included) like the sound of these amps very much. A lot has been written about this clever design and a quick Google search (try "citation amp" or "Matti Otala amp design") will probably be educational for you. In the end, however, the overall "sound" of the HK990 will be much more influenced by the DSP in the preamp section - if you use it.

Good Luck.

Martykl-- Magfan:

Thanks very much for all the good info.
It's not the amount of power but the quality of the power that matters.
You can find a lot of low watt amps that will better the sound of what you have.

It's been said, if the first few watts suck, why would you want more?

I find wattage highly over rated.

I went from 1000 watt mono blocks to a 2 watt amp and I never run out of power( 5 ohm, 90 db eff) or feel that it's underpowered.

There is as much sound in the room as before, and the bonus is that the sound improved with the lower watt amp.

I think your speakers are also not too power hungry, so don't limit your search to high power amps.
I used to drive Chevy Suburban, but now getting around with Toyota Camry. Camry in general is OK, however it will less-likely pull 25' Donzi on trailer.
I wouldn't try to pull much of anything with the Camry.
That's not what it's made for.

What I am talking about is that you only need brute force muscle amps if you are using speakers that demand such types of amplification.

For most moderate sized rooms and at normal listening levels, the first couple of watts(if they are good ones) are all you are using most of the time.

Lots of ink's been spilled on the need for massive amounts of reserve power for the times you need it, but really unless it's needed for sustained time frames(not instantaneous) you would be surprised by how few watts you are using to achieve decent sound levels.

It shouldn't be news to anyone that over the years most of the better sounding amps have been in the under 50 watt range,including a lot of the Pass designed class A amps.

I remember the 25 watt original Levinsons as being the poster boys of the 25 watters.

That was all the power you needed to drive the Quad 57's.

Using too much power was not good for the old Quads.

As long as you don't push a low wattage solid state amp into clipping,you should be fine with any of the better class A solid state designs.

Lower wattage PP tube amps around 35 watts have also been known to drive most speakers to adequate listening levels.

Not everyone needs high power amps to drive their speakers.
I don't.
My Ref 3A Grand Veenas sound great with a 2 watt DecWare Zen Select amp.
They also sounded no better or worse when I was using a pair of mono block power amps of a 1000 watts.

Like everything, you only need what you need, and most folks think they need too much.

I also know you don't bring a slingshot to a gun fight.

But each can be just as deadly when used in the right circumstances, ask Goliath.
While I might concur to your case Lacee,
I can't imagine swapping to 2...5W amp driving my Aerial 10T. Now they're driven with approx 700W of power in the medium size room with listening distance approx 5.5' and the same between speakers. I'm fairly satisfied with sound, but have to put some effort with acoustic treatments and probably switching to electronic crossover. The built-in one somewhat makes me think that it's not properly balanced.
Hi all ! I was part of thread not too long ago where everyone was adament I could not drive my Thiel 1.6's with my Cary v12 . It was pretty funny as nobody actually had the same amp and speakers but they were looking at the test data on the speakers . So the moral of the story never know until you try it .One other comment about amplifiers , in my experience the same amp model with the lower power rating usually sounds better .
Roxito why not ask people in the speaker forum who have your speaker what they are driving them with and if they may have tried other manufacturers as well;I do not think you should really be just looking at the specs and then buying;what you are trying to find is a proper match of amp to your speaker and maybe the 50 or 100 watt issue does not even come into play.
appreciate the responses.
Get a Kreel amp and you will have all the power you will need. You can never have to much power.
Good suggestion about Kreel:-)! I'd probably pick KSA250. It drives anything by any means!
I once believed the"you can never have too much power" credo. With exposure to the high quality low watt amps I discovered superior sound and better music reproduction(more natural and real i.e. less hifi or canned).
As long as there`s sufficient power for a given speakerload, the simpler less complex amps usually out perform. YMMV.
Speakers with a minimalist xover do not require very much power to sound good. Many of these exotic multi way speakers have very complex xovers that require mucho dinero amplifiers with enough current to power a small village due to the xovers gobbling up half the power before reaching the drivers. YMMV
By all means low-wattage amp can't reproduce real volumes of let's say acoustic upright bass even in the small room. High-efficiency low-wattage friendly speakers can't have sufficient bottom-end performance and lower efficiency full range speakers can't be driven by a few watts of power.
I agree with your 2nd point ( I clearly said amp has to match the speaker load demand-requirements).
Your first point I simply disagree with based on direct listening encounters over the years. A low power amp if matched with appropriate speaker(load and efficiency) will provide full and relistic bass(I know I`m not the only either).
If your experiences have been different no big deal I understand, but I know what I`ve heard. We`ll just have to agree to disagree that`s all.
Best Regards,
I'm running a dual transformer YBA amp which is 50 watts into my 86db Vandersteens, not a problem. I have a 200 watt Rotel and except for overall bass the YBA wins hands down. It's a small room and I listen to jazz mostly.
Sometimes there are exceptions to the audio rules.

My Ref 3A Grand Veena go down to 32 hz and my 2 watt SET amp delivers as much bass as my 1000 watt D amps did, and as much volume.

In fact I never have the Steelhead past 12 o'clock or the midway point.

The Grand Veena's crossovers (amp id directly linked to mid driver, tweeter, supper tweeter and woffers have crossover)are easy on my amp.

Here;s a ist of amps I auditioned in my system, before deciding what to purchase.
All amps drove the speakers well, didn't clip, and they all did the bass, to varying degress.

1961 Bell 18 watt tube push pull 4 6V6 tubes,
latest edition Mac 275,KT 88tubes, push pull,
Atmasphere S30-OTL,Grant Lumley -el34 push pull tube,
Art Audio Carissa, SET 845 tubes,
Pass labs Aleph 3-class A solid state
Red Draggon class D Leviathan mono blocks-1000 watts.

All the tube amps had a distinct sonic signature.
The Atmasphere and the Aleph had the best bass control.

The DecWare Zen Select-SET 2 watt, el 84 tube, was the purest of the lot, had no tube sonic signature, and did bass as well as any of the other amps.

I am more than pleased with the sound and dynamics this amp has driving my speakers.

After comparing it's sound with all the other amps, I found much to admire and nothing to fault,which should illustrate that you need to try amp/speaker combinations for yourself,and not rely on blanket audio statements and assumptions.

This is all the amp I need for my speakers and my taste in music runs from classical to jazz to rock.

There hasn't been a time on any type of music that I wished I had more power.

The only audio "truth" that I find applies, is that no amount of watts can improve the sound if the first few watts are not good.
Wonderful insight and true words of wisdom.Nothing beats real life experiences as examples.
Hi all ! Marakanetz : You obviously have not heard the Tekton Lore's with 10 or less wpc . Enough said .