Confused about dB's, Sensitivity....

[F1]

Every increment of 3dB you need to double the power, so here goes
1W - 89dB (at 1 meter)
2W - 92dB
4W - 95dB
8W - 98dB
16W - 101dB
32W - 104dB
64W - 107dB
128W - 110dB

As already stated, you need to substract few dB if you listen farther away from the speaker. The wattage rating on the speaker is probably exagerated to compensate exagerate rating of common amplifier/receiver. If your speaker is rated at max 120W, it probably means that the speaker can handle a burst of around 110dB before it breaks.

[kexodusc]

Some Sony's aren't too bad. The problem most people have with Sony is their inconsistency across product lines. They've really started to cheapen some of their products lately too, but they don't market themselves as "high-end" really anyway. I've been burned a few times by some of their products but some aren't bad. I bought my mom and dad an older Sony STR DE635(I think) off e-bay to replace my older pro-logic Marantz...it really sings in stereo mode, 80 Watts/channel both channels driven, 20Hz-20kHz low THD and would go toe-to-toe with that Marantz easily....the power really dies once you drive all 5 channels, and the distortion rises but it's still more than loud enough for them and the distortion is more than tolerable for HT playback anyway. It does have cheap feel compared to my Marantz and Yamaha gear, the back is quite flimsy etc, but it works, was a steal for me and they're happy.
What really ticked me off is Sony decreased the dynamic range on it's replacement products to 40hz with more distortion. They lowered the price and addes some more DSP's and inputs. The power supplies appear to be cheaper too, but I think this line is made more for entry level HTIB setups now than larger speakers.
If you ever have a technical problem though, Sony's got some "issues" to say the least.

Joel2762: It's never easy matching speakers to amplifiers according to power ratings. Too many variables are often used to arrive at the desired numbers. I destroyed a set of old Wharfdales that were supposedly good up to 80 watts with a 35 watt Harmon Kardon amp way back. My own fault, but it was hard lesson that tought me not to always rely on specs. If you really feel the need to crank your system, don't just give it the juice, go up in small steps for a good 5-10 minutes at a time...if you notice any clipping or funny sounds cut back the juice immediately.

[Sir Terrence the Terrible]

Before we get locked into believing we don't really need that much power, you have to think in term of frequency versus power. If you are talking about 1khz as being the reference tone, then F1 power chart makes since. But as you plummet in frequency, in order to hear the same volume as the one attained at 1khz, the power must increase dramatically. 100 watts at 20hz doesn't produce nearly the same amplitude as 100 watts at 1khz.

At this point you now have to think of headroom. Especially with film soundtracks which can have extreme amplitudes swings(as much of you complain about so frequently) especially in the deep bass area(film soundtracks are the only audio genre to have very deep bass frequently and very loud). A full scale explosion may require ten to twenty time the power demand to reproduce the deep bass frequencies cleanly, with no compression or clipping.

I alway tell my clients don't think of getting just enough, you always need just a little more to play cleanly during peaks. Just enough during peaks will get you compression, just a little more will keep distortion down, clarity up, and compression out.

[kexodusc]

Sir Terrence, I agree with your points. However I would point out that most setups I've seen today can be classified in one of two situations:
1) The sytem includes a subwoofer which generally has it's own amplifier, reducing the need for power
2) The system includes main speakers which are very capable of reproducing low, extended bass frequencies - I would suggest this scenario often finds audiophiles with more expensive, better performing speakers, which almost certainly have a more powerful amplifier anyway.
Not to discount what you said, but I certainly wouldn't want to mislead people who are buying a home theater in a box system that that extra 200 bucks to get to 100 watts per channel is worthwhile when their small cube speakers will have difficulty with 80 watts.

It happens too often in my opinion, and let's face it, us men are generally impressed with "more" of just about anything, especially power. I can't really blame a salesperson for trying to earn a buck.
At the same time, having more power probably gives you more upgrading options, and from what I've seen, often means a better power supply, which isn't a bad thing.

[spacedeckman]

Numbers make the most convenient comparisons for audio products.
Numbers are typically the most useless for comparisons of audio products.

As soon as you start getting hung up on numbers when you buy audio products, that is when you start screwing up. You see, different companies see different things when they publish specifications. Some see a marketing opportunity, some see an opportunity to fudge a bit, and others try to convey something useful. Unless you know where the manufacturer is headed, you are chasing the wind.

Speaker sensitivity is a bit misleading as a concept to the uninitiated, but is a very common place for very respectable speaker companies to "fudge" a bit. A couple of dB between friends doesn't really hurt anything, but often you will find something on the lines of double that which is starting to make a difference. As Terrence brought up, that 1k thing kind of gets in the way too. As you go deeper, your power demands increase, but still, you can go a long ways on a handfull of watts, even if the hand was involved in an industrial accident and a finger or two is missing. Speaker power ratings? Give me a break. Take a 400 watt speaker. Hook it up to a 100 watt receiver. Crank it up. Toss the tweeter. What did that rating gain you? NOTHING. It can be useful with small speakers, or when you are employing big amplifiers at silly volumes for extended periods of time. Other than that...not very useful. How many people does the number help? A fraction of a percent. Speaker frequency response? The raw number is often bogus enough, but how many companies put the size of the "window". A speaker that is 30-20k +/- 20dB is sure to be a real "winner", so the +/-20dB "conveniently isn't listed. Impedance? Nominal is really cool...sort of (only a hint of sarcasm here) Many companies are really good with this, and with mainstream speakers it is getting to be much less of an issue. Most of these companies have really worked on "dummying down" impedance curves to work with the current generation of fairly crappy receivers.

Receivers? 100watts...sure...at 1k. What the heck kind of rating is that? I remember being disgusted with a Sony entry level piece 17-18 years ago that listed 40-20k. 1k is not only a whole lot worse, it is far more openly accepted by those who don't have a clue. I vote for a total ban, same for power ratings at 6 ohms. Panasonic has one that does both. 100watts/1k/6ohms/1%THD...think we may have some engineering problems here? What's wrong with calling it a 60 watt receiver, or even 50 and make it work? Idiots want 100 watts. MARKETING!!!! I've spent most of my audio existence with 50 watts or less, and I bought my first real system 24 years ago when I was in college. I still have the 20 watt receiver I bought back then. I've nearly doubled to 35 watts today. So what!!! I only wish it was possible to go back to the days when it was okay to make a 40 watt receiver that could actually drive a real world speaker load and make some bass. The world was a better place then. Quality over quantity, because quantity is a bunch of crap. While you are at it, make sure your video switching isn't goofing up your video quality, and the things you paid for actually do what you expected. You are most often much better served with a smaller receiver from a reputable "upscale" company than a "big" one from a mass market company.

So Joel, the more time you spend fretting about numbers, is less time you spend listening to your system. Don't sweat the Sony. Sony is all about learning curve. If you like audio, you've already made that mistake and you will be ready to move on in the future. For now, it works, and enjoy it. A better piece lies ahead. If you are perfectly happy with it, please be so, and don't worry about the numbers stuff. If you are hanging out here, you have already started a journey that could bring you places you never imagined. This is all about fun. But, this was a good question because the more you know, the more fun you will have in the future...and the more you will understand how much more there is to learn. Also, beware those who know everything, they are too dumb or closed minded to realize there is always a ton of stuff we don't understand. Discovery is one of the best things about audio. And, thanks for letting me vent. I feel better now.

[Sir Terrence the Terrible]

Sir Terrence, I agree with your points. However I would point out that most setups I've seen today can be classified in one of two situations:
1) The sytem includes a subwoofer which generally has it's own amplifier, reducing the need for power
2) The system includes main speakers which are very capable of reproducing low, extended bass frequencies - I would suggest this scenario often finds audiophiles with more expensive, better performing speakers, which almost certainly have a more powerful amplifier anyway.
Not to discount what you said, but I certainly wouldn't want to mislead people who are buying a home theater in a box system that that extra 200 bucks to get to 100 watts per channel is worthwhile when their small cube speakers will have difficulty with 80 watts.

It happens too often in my opinion, and let's face it, us men are generally impressed with "more" of just about anything, especially power. I can't really blame a salesperson for trying to earn a buck.
At the same time, having more power probably gives you more upgrading options, and from what I've seen, often means a better power supply, which isn't a bad thing.

Kex,

My point was not to get our fellow hometheaterans(is there such a word?) to run out and buy a amp that is 200watts+5 for a subsat system. My point is to simply illustrate that because of the fletcher munson curve we have to consider looking at how many watts are required by FREQUENCY, and not just by some arbitrary numbers, or by what is reproducing the bass(whether its mains or a sub)

There is a reason why most sub amps wattages lie in between the 125-250 watt range and above. That is because the power requirements for bass frequencies are so much more than for treble frequencies because of our hearing insenstivities at the freguency extremes.
So whether you use a sub, or have full frequency mains, you still need substantial power for clean low bass reproduction. If you look at it this way, then asking a cube that struggles with 80 watts to be used with a 100watt amp is unecessary. You know the cube won't be able to reproduce deep bass anyway!!

I am not for power just for the sake of power. I am for power where it is needed. No use in having a Porsche if you only drive it on city streets, right?

[joel2762]

Hey everyone. Thanks for all the comments. I belive my Sony drives 40Hz-20Khz with 0.09% THD...It sounds good enough for now. It's only a small room, it does fine in here. I can't drive it to clipping because i'd go deaf! It's a great system anyhow. Might not be the audiophile gear but it sounds great! It does sound a little clearer in 2CH mode rather than DPLII. But it still sounds good. I crank it lots of the time but never into distortion. I don't think it can be played that loud in this room anyway but sometimes the bass can get distorted at high levels but that's just waht happens! Thanks for all the help I learned a lot!

[joel2762]

As spacedeckman mentioned about the video swithcing goofing it up. It only has composite switching, but when I got it, I knew I wasn't going to use the internal switching anyway. I have my DVD player hooked directly to my tv using S-Vid, hopefully going to change that to Component soon. I use the reciever switching for my VCR and the A/V cord from a digital camera.