Watts and what they can do

[Z3r0]

Hehe ok ok last post b4 i go and buy my receiver =/

I was reading an article and it says that 40wpc is just as good as 100wpc, to notice a difference in volume you would have to have 500wpc. Is this true? Because i was looking and some Hamaron & Kardon receivers and they only pump out 40wpc. I thought i would need a high wattage to power my large floorstanding speakers? Thx

[E-Stat]

Hehe ok ok last post b4 i go and buy my receiver =/

I was reading an article and it says that 40wpc is just as good as 100wpc, to notice a difference in volume you would have to have 500wpc. Is this true? Because i was looking and some Hamaron & Kardon receivers and they only pump out 40wpc. I thought i would need a high wattage to power my large floorstanding speakers? Thx
Here's the basic rule: you have to double power to get a 3 db increase in sound level that many consider the least significant audible difference. A tenfold increase in power, all things being equal, will double the apparent loudness. I say all things being equal because you must look carefully at how the power ratings are stated. Some manufacturers do not rate their amps to produce the same power at the frequency extremes. The load or impedance is another variable. Most solid state amps are capable of producing higher power at a lower impedance, say 4 ohms vs. 8 ohms. You need to compare apples to apples and sometimes that is not necessarily easy to do.


As for the size of your speakers, size doesn't matter - effficiency does. There are some very large and efficient horn loaded speakers available that work well on just a couple of watts.

rw

[gonefishin]

To add to what E-stat said. Watts are all really relative to what system and room they're in. How large of a room and how easy are the speakers to drive. 40 Watts will reach different volumes on speakers rated at 87db and rated at 105db.


It's just too tough to make an accurate statement with such generalization like that. It can just vary too much on the components of each system.

[Smokey]

To add to what E-stat and Gonefishing said, when comparing power capability of an amp, one also take into consideration its Dynamic Headroom (in dB), and THD (Total Harmonic distortion) rating as they are very much related.

For example, if you look at some of boomboxes out there, some of them are rated at 200-300 watts of power. But their THD rating is usually very high (in the neighborhood of 10%), and not much Dynamic Headroom to speak of.

[hershon]

Maybe someone can explain this to me (I put out a similar thread a few months ago)- if I play a CD in an apartment and the volume level is saying hypothetically set at 8 for a 500 watt system and I play the same CD on a 1000 watt system at 4 volume- thus the loudness is relatively the same level, what exactly would I notice differently playing say a rock CD or would I notice anything at all. I'm not concerned with how watts sound differently played in a huge hall or anything, just in a normal size apartment living room. Any insight would be appreciated.

[topspeed]

Maybe someone can explain this to me (I put out a similar thread a few months ago)- if I play a CD in an apartment and the volume level is saying hypothetically set at 8 for a 500 watt system and I play the same CD on a 1000 watt system at 4 volume- thus the loudness is relatively the same level, what exactly would I notice differently playing say a rock CD or would I notice anything at all. I'm not concerned with how watts sound differently played in a huge hall or anything, just in a normal size apartment living room. Any insight would be appreciated.
That's a tough one to answer Hershon, because a lot of it would depend on what your are driving. Using your example, chances are you wouldn't hear much of a difference merely because 500 watts is more than anybody, anywhere, driving anything will ever need in a domestic application. However, if we brought that down to say a 50 watt amp vs a 100 amp and connected them to say a Martin Logan Ascent i (w/ its 1.2 ohm dips), I think you could very well hear a difference on demanding material simply because the more powerful amp has more headroom. There wouldn't be as much evidence of strain. Naturally, the difference would become more readily apparent as you climb up in volume. I'm no engineer (too bad Skep left), but this would seem logical.

[E-Stat]

Maybe someone can explain this to me (I put out a similar thread a few months ago)- if I play a CD in an apartment and the volume level is saying hypothetically set at 8 for a 500 watt system and I play the same CD on a 1000 watt system at 4 volume- thus the loudness is relatively the same level, what exactly would I notice differently playing say a rock CD or would I notice anything at all. I'm not concerned with how watts sound differently played in a huge hall or anything, just in a normal size apartment living room. Any insight would be appreciated.
Consider that relative positions of volume controls, be they conventional knobs or digitally controlled ones, are largely irrelevant. This is due to different output voltages from sources and different input sensitivities with amplifiers.

In your example. so long as the lower powered amp playing the rock CD was not clipping, then I would say that there would be nothing to gain by using the higher powered amp, assuming they are of equivalent sonic quality. I have a pair of 500 watt amps in my primary system. On average, I would guess that rarely do I ever use more than 10 watts or so. It is only when I play highly dynamic material that the peaks require all I've got - and then some. This happens with some 12" 45 RPM Madonna singles from the 80s as well as a number of classical recordings.

rw

[kexodusc]

Yeah, Skep would have a page or two of opinion on this...but here's mine.

Hershon:
I have 2 Adcom power amps that are at least 95% identical as far as parts go, the only difference is one is rated at 60 watts/channel, the other is rated at 200 watts/channel.
When I hook them up to my Studio 40's and play a cd or dvd, I can't hear a difference in any tonal qualities or bass or anything like that at most volumes. When I really turn it up loud to volumes that are far too loud for inside my house, the 60 watt/channel GFA-535II starts to reach it's limits on musical peaks in volume, and the distortion alerts light up a bit. You can start to hear the sound quality deteriorate (clipping, etc) but it's hurting my ears and pissing off my fiancee at this point anyway. Those 60 watt Adcom's work great. I have some 40 watt Nad amps that do just as well in my opinion.

It becomes really apparent that I can drive the absolute hell out of my speakers with the 200 watt/channel Adcom GFA-555 II...they'll continue to put nice, clean well defined sound at rediculously loud levels, well past where the 535 stops, and the amp's distortion alerts are not being lit up at all. It doesn't appear to be "strained" or anything. The problem is my Studio 40's can really only handle up to 180 watts or something according to the specs, and even that I think is a stretch...I don't want to test that because I risk damaging them.

So 200 watts would give me room to go even louder than what I consider way too loud for my speakers. At this point, it is useless to me with those speakers. The GFA-535II has 4 or 5 dB of dynamic headroom and since I probably rarely use all 60 watts of it's power, I don't hear any sound problems at all.

Now, I have a pair of great souding speakers with VIFA drivers that I love way more than my Paradigm's, but their sensitivity is probably in the mid to high 80's, I'd say a good 3 to 5 dB lower than my Studio 40's. This means I probably require anywhere from 2 times to 4 times as much power to generate the same volume as my Studio 40's. This might present a problem for a 40 watt or 60 watt amp at higher volumes. I use a Rotel integrated amp that has 100 watt/channel and it goes way more than loud enough while still sounding good for my purposes. But that same 200 watt/channel amp can now only drive those speakers to the same volumes (approximately) as the 60 watt/channel amp can drive my other speakers. (Note: I've never done an actual test to prove this)

Hershon, as far as I can tell, if I use both Adcom amps to drive my speakers to the same volume, then they are both delivering pretty much the same number of watts to each channel. The fact that the 555 has 200 watts/channel is meaningless because it's only sending say 10 watts most of the time, the same as the 60 watt amp to achieve the same volume. The only advantage to the extra power I can tell, is when I continue to turn the volume up and it requires say, 70 watts/channel during peaks, or more...well, the 60 wpc amp has run out.

1 watt is pretty loud. Don't be sucked into spending huge bucks on power that you don't need. But make sure you get enough power!!! In home demos with your equipment is the best, easiest way to make this determination.

[Z3r0]

Srry i didnt get back to you quicker, i went to bed after i posted =/ ne way...

My rear speakers are 88db (operate from 15-150w)

My front speakers are 90db (operate from 10-250w)

http://www.circuitcity.com/detail.jsp?c=1&b=g&u=c&catoid=-8021&qp=0315331513152&oid=81873&m=0

Thats the one i was looking at, im going to my marantz local dealer today so ill c what they have as well.

[kexodusc]

BTW, Z3r0, H/K rates their receivers with all channels driven, and they typically have a bit more headroom than receivers like Yamaha, Marantz, Denon, etc...
That unit is a 45 wpc receiver, My old Marantz was rated at 85 wpc, but with all channels driven it couldn't even hit 45 wpc, so take that for what it's worth. Similarly, I'd be surprised if my new RX-V1400 Yamaha rated at 110 wpc could hit 60 wpc with all channels driven. There's plenty of power in those H/K receivers. Don't let the wpc specs influence your decision (too much).

[N. Abstentia]

Just adding on to the Adcom amps..remember that a receiver rated at 100 WPC could never ever even on it's best day even come close to a seperate 100 WPC amp (as long as it's of high quality..such as Adcom).

If you feel you need more power, buy a seperate amp and not a slightly larger receiver that 'appears' to produce more power. Fact is, it's still a reciever and the amp in it is compromised. Heavily.

[nightflier]

I used to own an old HK20 receiver, and I still kick myself for giving that one away. Just recently I found a great deal on the HK DPR1001 receiver, rated at just 50W, so I figured what the heck, let's see what HK has done lately. I have it set up with a 7-speaker Axiom setup and a SVS sub. The receiver replaces a much more powerfull Onkyo receiver.

While I was changing out receivers I had some time to play around with both and see what they could do. I even set up the Onkyo as a dedicated amp with the HK as a preamp. There are definitely some striking differences between the receivers, but the one thing I am certain of, is that the 50W per channel was more than enough for my surround setup. Onkyo makes an excellent receiver, but the HK is hands-down better. It is more efficient, more dynamic, and more powerfull. I'm not an expert, but it just sounds more detailed and airy, which I think is what the other posts mean by "headroom." I have been a fan of Onkyo for some time (just check my other posts), but the HK is a better value at a lower price. Some people don't like the remote, and it is a bit quirky, but that is a small thing compared the the value of this receiver. The HK 130 is also very well reviewed.

If you need more power, check out the HK 7200, because it is a couple of years old, you can get that model for a fraction of what you would pay for a comparable unit. It sells for around $500, if you can still find it. It has been replaced with the $2000 HK 7300, but there are just few differences.

Anyhow, that's my 2 cents.

[Woochifer]

Unless you're trying for rock concert levels in your living room, you'll rarely even come close to hitting the maximum wattage on that receiver. Most speakers will already be at the high end of most normal listening levels with only about ONE watt of output. With the speakers that you posted, you're looking at decibel readings in the mid-80s with one watt. That's already pretty loud, and going into the mid-90s only takes about 10 watts.

Rather than focus on quantity, just listen for any significant sonic differences between the amps. In all honesty, the sound quality differences between comparably priced receivers, especially in the entry levels, are subtle at best. You should look more at stuff like the build quality, user interface, connectivity, and features, because those vary a lot more between different models. The differences between speakers are far more obvious, so you should really key on that as the main variable in your system.