Confused about dB's, Sensitivity....

[joel2762]

Thanks alot, I get it now. That's pretty interesting though because you'd think you'd need more than a watt to drive speakers loud. But I guess that's not true! My reciever manual states that the volume control increases by 1 dB each step. I listen to it around 45-50 depending on the level of the recording pretty much everyday. I don't crank it to dangerous levels, it'[s only a small room but every now and then on the weekend might put it a little louder for a little while. I just like bass, before I had my subwoofer, I could not achieve the bass I wanted from my speakers without having it too loud. Now I have a sub it all blends in.

[kexodusc]

This was a really good thread, I don't think this question gets asked enough, especially by newer audio enthusiasts or people looking to build their first systems.
I get people asking me all the time and I hear it at places like BestBuy and Sears, "is it worth that extra hundred bucks to get that extra 10-20 watts?"
They perceive the difference between 80 watt and 100 watt receivers as a factor of 20%...You wouldn't believe how many people drop 100-200 bucks extra here thinking they need it.
I always tell them that unless there's some other features that they absolutely need or like on the receiver, if everything else is equal, they've got better places to spend that 100-200 bucks on than going to 100 watts per channel. Geez, I love it when newbies look at Harmon Kardon receivers with 35 or 45 watts/channel and think "rip-off", then proceed to buy the 120 watt/channel Kenwoods.

Why would you drop 200 bucks for more power that isn't going to make a big impact and you don't really need?
Some brands are really bad, they up the power by 5 watts, add 1 more a/v connection, a DSP or two, and charge 150 bucks more for the receiver.

[magictooth]

Hi!

I thought that I should post a slightly contrarian point of view. While I agree with everything that the above posters have said, you should be aware that the extra watts are not absolutely wasted.

For the most part you have a desired listening level - say 75 dB. However, the one thing that the other posters haven't mentioned is the dynamic range that most movies have. You may like listening to conversation at 75 dB, but there will be times when you get a spike in volume level such as in an explosion or even something simple like a heated argument. At those times, you want to have the extra power available to fully express the dynamics in the soundtrack.

[kexodusc]

Hi!

I thought that I should post a slightly contrarian point of view. While I agree with everything that the above posters have said, you should be aware that the extra watts are not absolutely wasted.

For the most part you have a desired listening level - say 75 dB. However, the one thing that the other posters haven't mentioned is the dynamic range that most movies have. You may like listening to conversation at 75 dB, but there will be times when you get a spike in volume level such as in an explosion or even something simple like a heated argument. At those times, you want to have the extra power available to fully express the dynamics in the soundtrack.

That's a good point magictooth, and I agree with your logic, I'm just not convinced that a 5 or even 10 watt per channel difference will be of much value once you get over the 40 watt range for spikes in volume in most "moderate" sized home theater or stereo setups.
I'm only basing this on my past experience with 2 of my Marantz receivers...I ugraded to an extra 15 watts per channel from 90 to 105, and didn't notice a difference at all in performance or anything, and was kind of disappointed that I dropped money on the extra power after I realized I rarely ever come anywhere close to using it's full potential. I could be wrong because I never compared the receivers back and forth playing the same movie against each other, I was just expecting the extra power to improve sound quality or really shake the house.

[joel2762]

I see now, so the extra power really doesn't matter that much in most cases. My Sony is 100 watts per channel. I know that it's not really that powerful but it does job and plays loud enough for me. I noticed with the old Realistic reciever we used to have before upgrading to surround, it sounded more like. Powerful. Like real power. But the Sony's still good all the same. It's cool though, I never would have thought that speakers could go that loud with 1 watt! But one thing that's confusing me...If my speakers say 15-120 watts, how can they go to nearly dangerous levels with only a watt. What's going on that i'm not getting...

[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.