Watt nonsense!

[toddalin]

The speakers and all ancillary equipment used was state of the art in 1987.

Doesn't matter. Different speakers will react differently to different amps. And the speakers were not selected as state of the art but rather a medium efficiency load that was thought to apeal to the select crowd. An ESS AMT, horn, or ... may have shown totally different results because they place different demands on the amp. Back when this test was done, nobody even thought about EPDR (which can be well under 2 ohms) and its effect on amps and the frequency band.

If you read the technical amplifier tests in Stereophile you'll find that they run frequency curves both into a steady load (e.g., 8 ohms) and a simulated speaker load. The simulated speaker load is NEVER flat and its degree of variation varies with the architecture of the amplifier and its output impedience. And every speaker is going to have a different load/phasing across its frequency band so will interact a bit differently with every amp.

 

[ernieb1536]

I don't believe that, I really don't care what magazine said what unless you have some sort of hearing problems that you cant determine a difference in the sound between 12 totally different amps, now you may not be able to pick out which amp is which but certainly anyone with halfway decent hearing should be able to hear a difference. Just because someone wrote something in a magazine or online does not make it so.

Have a sta2080 and a sta2290 realistic recievers one 80wpc the other 90wpc on the same speaker the sta2080 has better midrange and is more musical the sta2290 sounds good but not as musical bass is also better on the sta2080 the sta2290 has a wider sound stage on fm both same manufactor similar power but different sound signatures

 

[chef free]

HELLO AND WELCOME!

Here's what I think:
1. To make the music sound twice as loud, you need to raise the volume about 10db, which requires a quadrupling of watts.
2. I used big power amps, 400 watts per, because my speakers are very low sensitivity, about 81dB. More sensitive speakers will play louder with less watts.
3. Yes, some sources have greater output. The overall loudness won't be greater however because there is a limit to total output.
4. I don't know about Pioneer's engineering but I do know I never had a receiver that could be turned about 1/3-1/2 volume with regular inputs.
(Since we are talking about receivers, we're talking about pre amps, some have different output levels)
5. Headroom allows for quick moments of power for big crescendos. It seems to control the woofers better to use high power amps too.

 

[Snow]

Have a sta2080 and a sta2290 realistic recievers one 80wpc the other 90wpc on the same speaker the sta2080 has better midrange and is more musical the sta2290 sounds good but not as musical bass is also better on the sta2080 the sta2290 has a wider sound stage on fm both same manufactor similar power but different sound signatures

That is my point is that some people at least can differences in different amp and receivers even though yours only has 10 WPC of difference between the two. For those that think all amps sound the same research Bob Carver.

Regards Snow

 

[HidetheHiFi]

Several folks in this thread have given good input on this already. Maybe a short "cheat sheet" will help as you read their responses.

First, here are two key things to keep in mind:

• A change of 3db is a "noticeable change", not a huge change.
• A 3 dB increase requires double the power from the amp.

And- your Celestions have a sensitivity rating of 90 db, which means that they produce 90db of " loud" from 1 watt, measured one meter from the speaker.

With that, we can make a table like this to see how loud things can go at various wattage:

1 watt = 90 db
2 watts = 93
4 watts = 96
8 watts = 99
16 watts = 102
32 watts = 105
64 watts = 108
128 watts = 111
and so on...

At the levels I normally listen to, my amp loafs along at less than 1 watt. But there can be sudden peaks from drum strikes or orchestral crescendos that ask the amp to quickly deliver WAY more than one watt. When that happens, the extra watts (aka headroom) from a larger amp come into play.

Hope that's not a re-hash of things you already knew! When I was trying to figure out how large an amp I needed, basic stuff like this helped me figure out roughly where I needed to be as a starting point.

That's extremely useful, thank you, was not aware of the watt doubling per 3db rule - very handy! Does it still hold true for highly sensitive speakers, like Klipsch Forte etc? If they only need, say, 1 watt to play at 99 decibels, then they only need 8 watts to play at 108db, whereas the Ditton 25s would need 64 watts?

 

[HidetheHiFi]

You're entirely fixated too much on raw wattage numbers which is only one side of the SPL (sound pressure level) equation. Just as important, if not more so, is loudspeaker sensitivity. For example a loudspeaker with 110 dB sensitivity will play just as loudly (at maximum) driven by 1 watt amplifier as an 80 dB sensitivity speaker driven by a 1,000 watt amplifier. Now that doesn't take into account the very different sonic characteristics that are likely to exist between two such speaker designs, ie: the lower sensitivity model will probably have superior low frequency response while the mids on the high sens model will be more pronounced, in essence more "volume" in that part of the frequency spectrum.

Secondly, when amplifiers are operated within their output limits for clean power (ie at low distortion), there is no reason one should sound any "louder" than the other assuming they're both operating properly. The loudspeaker has no way of knowing, nor responding any differently whether, say a 10 watt signal is being supplied by a 20 watt amplifier than 10 watts being supplied by a 1,000 watt model. It is when you feed the speaker more power than the lower power amplifier is capable of - only then would the higher powered unit make any difference in loudness.

Yes, very valid point, I accept I did not factor in speaker sensitivity, but I'm aware that has a big, perhaps greater impact on SPL than amp output, but apart from horn speakers I'm guessing the majority of "normal" speakers are between 85db/w/m and 95db/w/m and so my big old Celestions are around the middle of the road

 

[HidetheHiFi]

O.K. Let's try this step by step.
Point No1. - (and probably the most important) - Remember that high fidelity sound reproduction is more about quality then quantity - you are not running a PA system in your living room. Refer back to the old adage - the most important watt is the first one.

You power ration of 10:1 is probably about right. How loud a system goes is as much about the efficiency of the loudspeakers as the maximum output power of an amplifier. Input sensitivity will also play a major part in this as will amplifier gain factor You will see an output power rating in watts and an input sensitivity in millivolts (mV). Low efficiency loudspeakers require far more input power to produce the same audible sound level as a high efficiency loudspeaker. Again you 10:1 ratio applies.
example:
Amplifier A - Input sensitivity 250mV for full output of 50watts.into an 8 ohm load.
Amplifier B - Input sensitivity 500mV for full output of 100 watts into an 8 ohm load.

I you feed both these machines with a 200mV signal, amp A will probably produce about 40watts, amp B will probably produce about the same. look at the relationship between input sensitivity and output power in each case.

CD players do tend to have a higher output than most other sources. There is no advantage in trying to increase the output of other devices. They are what they are and largely you have to live wit this.

Headroom. You run a hi-fi amp at a relatively low average power level. I have a rule of thumb that says 'If you need to run an amp at above 50% volume setting it's not big enough'.
If you are running a music signal at a reasonable power level and a loud transient occurs in the music (a load bass drum or similar), although the average power level is hardly affected, the amplifier will be required to draw a large current for a very short period to enable the output voltage to correctly follow that transient. That ability to draw extra current for a very short period without clipping is called 'headroom' and it's also where your 10:1 power to volume ratio applies.

I hope this helps to at least start to answer you questions. This is just skimming the surface as I have tried not to be too technical for you.

Very much appreciated, thanks Powertech. And yes, I know it's not all about the power, but I confess the first thing I do with a new amp or speakers is go to my Test playlist and play the loud ones first, before the female vocalists and pianists get their turn! CS

 

[Chris Brown]

1. To make the music sound twice as loud, you need to raise the volume about 10db, which requires a quadrupling of watts.

Empirical data would seem to suggest that it takes 10 times the output power to make the music twice as loud. Quadruple the power would result in a +6 dB increase.

Increases in Power / Voltage / Decibels:
1.26 x power (watts) = 1.12 x voltage/excursion = +1dB
1.59 x power (watts) = 1.26 x voltage/excursion = +2dB
2.00 x power (watts) = 1.41 x voltage/excursion = +3dB
2.52 x power (watts) = 1.59 x voltage/excursion = +4dB
3.18 x power (watts) = 1.78 x voltage/excursion = +5dB
4.00 x power (watts) = 2.00 x voltage/excursion = +6dB
5.04 x power (watts) = 2.24 x voltage/excursion = +7dB
6.35 x power (watts) = 2.52 x voltage/excursion = +8dB
8.00 x power (watts) = 2.83 x voltage/excursion = +9dB
10.0 x power (watts) = 3.16 x voltage/excursion = +10dB

 

[dcmfan]

Does it still hold true for highly sensitive speakers, like Klipsch Forte etc?

Yup!

Keep in mind, though, this is the "super simplified" version of things. There are a lot of other factors that can affect how an amp works with a set of speakers, but understanding how amp power, speaker sensitivity and decibel levels are related is fundamental. At least it was for me.

 

[BMC]

Try comparing a NAD 7155 - 55 watts with 6db of headroom and a MCS 3253 - 53 watts with less than 3db headroom. It’s night and day on my system. The power supply on the NAD leads to a much beefier sound with solid bass. While the MCS has a softer looser bass. Seems like power supplies like the NAD are a rarity in receivers.

 

[Semanon]

Empirical data would seem to suggest that it takes 10 times the output power to make the music twice as loud. Quadruple the power would result in a +6 dB increase.

Increases in Power / Voltage / Decibels:
1.26 x power (watts) = 1.12 x voltage/excursion = +1dB
1.59 x power (watts) = 1.26 x voltage/excursion = +2dB
2.00 x power (watts) = 1.41 x voltage/excursion = +3dB
2.52 x power (watts) = 1.59 x voltage/excursion = +4dB
3.18 x power (watts) = 1.78 x voltage/excursion = +5dB
4.00 x power (watts) = 2.00 x voltage/excursion = +6dB
5.04 x power (watts) = 2.24 x voltage/excursion = +7dB
6.35 x power (watts) = 2.52 x voltage/excursion = +8dB
8.00 x power (watts) = 2.83 x voltage/excursion = +9dB
10.0 x power (watts) = 3.16 x voltage/excursion = +10dB

Very nice chart. Equally important is the level as the distance from the listener to the speaker increases. For every doubling of distance, the SPL drops by 6dB. This results in the following levels for a speaker with a 90dB sensitivity:

@1 m = 90dB
@2m = 84dB
@4m = 78dB
@8m = 72dB
@16m = 66dB

So, to keep the same SPL as the distance to listening position doubles, one needs to quadruple the wattage required, per the inverse square law (assuming sound radiates as a sphere).

1 watt at meter = 90 dB. @2 meters it’s 84 dB, so 4 watts is required to overcome 6dB lost due to the increased distance. This does not come into play much with home audio, as it’s hard to do more than a few doublings before you are in the next room.

 

[toddalin]

Very nice chart. Equally important is the level as the distance from the listener to the speaker increases. For every doubling of distance, the SPL drops by 6dB. This results in the following levels for a speaker with a 90dB sensitivity:

@1 m = 90dB
@2m = 84dB
@4m = 78dB
@8m = 72dB
@16m = 66dB

So, to keep the same SPL as the distance to listening position doubles, one needs to quadruple the wattage required, per the inverse square law (assuming sound radiates as a sphere).

1 watt at meter = 90 dB. @2 meters it’s 84 dB, so 4 watts is required to overcome 6dB lost due to the increased distance. This does not come into play much with home audio, as it’s hard to do more than a few doublings before you are in the next room.

Doesn't apply in an enclosed environment unless it is anechoic.

 

[dcmfan]

Very nice chart. Equally important is the level as the distance from the listener to the speaker increases. For every doubling of distance, the SPL drops by 6dB. This results in the following levels for a speaker with a 90dB sensitivity:

@1 m = 90dB
@2m = 84dB
@4m = 78dB
@8m = 72dB
@16m = 66dB

So, to keep the same SPL as the distance to listening position doubles, one needs to quadruple the wattage required, per the inverse square law (assuming sound radiates as a sphere).

1 watt at meter = 90 dB. @2 meters it’s 84 dB, so 4 watts is required to overcome 6dB lost due to the increased distance. This does not come into play much with home audio, as it’s hard to do more than a few doublings before you are in the next room.

I've had some fun with this calculator: Peak SPL Calculator

It factors in speaker sensitivity, distance of listening position, and amp power to show the maximum SPL level at the listening position.

I used it to try and estimate how many watts I use for the 75 db I usually listen at and it's well under one watt.

 

[rothwellaudio]

Equally important is the level as the distance from the listener to the speaker increases. For every doubling of distance, the SPL drops by 6dB.

Doesn't apply in an enclosed environment unless it is anechoic.

Yes, the 6dB drop per doubling of distance is often quoted but doesn't hold true in a domestic living room.

 

[Semanon]

Yes, the 6dB drop per doubling of distance is often quoted but doesn't hold true in a domestic living room.

It does not hold true in any reverberant environment, but the physics are still valid, and it is where the concept of quadrupling the power to get a 10 dB increase in SPL comes from. Simple math is instructive but becomes inaccurate in complex environments.

 

[hopeless]

I agree. There seems to be a commonly held belief that any 50 watt amp is pretty much the same as any other 50 watt amp, and that any 100 watt amp is exactly the same as a 50 watt amp except it has 3dB more headroom. If that was the case it would be entirely appropriate to focus on calculations regarding speaker sensitivity, listening distance and maximum SPLs, and a more powerful amplifier would always be preferable to a less powerful amplifier, but I don't believe things are that simple. Some amplifiers are capable of maintaining control and revealing all the subtle details in a recording whereas others seem to turn everything into a raucous din, and that's long before the clipping limit is reached.

Exactly. You can't directly compare specifications from one audio product to another. Specifications are incredibly unreliable, especially at the bottom end of the scale. That 100 watt receiver is "100 watts" until you hook up a pair of speakers. Those 100dB speakers at 1k are not near that anywhere else. Some amplfiers do sound better than others. It's all about the amplifier being able to address the speaker load even before you discuss the demands of music, volume level, and room size.

I've had big and small amps, tube and solid state. Tube performance is pretty much dictated by iron. Solid state is a bit more finicky. Good iron is a necessity, but power supply and circuit design play a much bigger part. Trying to keep this really simple and staying in the SS lane.

Many moons ago I read an article in a magazine (remember Hi-Fi magazines?) that ran a detailed blind study of about a dozen amplifiers at all kinds of price levels and topologies with an "audiophile" audience. The conclusion from that study if I remember correctly was that all amplifiers sound the same as long as they are not clipping. It actually took me some years to get over that and what finally did it is that I realized that I had started listening less and less to my music as I had purchased generic super low distortion amps. It just became kind of annoying sonic wallpaper. Fortunately I'm enjoying and paying attention to my music very much these days. I think we are fortunate to live in the best of times Hi-Fi wise ( except for some of the prices!)

Probably Stereo Review. They wrote the book on everything sounds the same. Can't think of his name right now. I can tell you that with a good source and decent speakers, he was wrong. His source was typically FM radio. Compressed and bandwidth limited.

I spent a long time in the industry doing volume matched amp demo's. People nearly always heard a difference. In my own experience, amps with stiff power supplies and beefy output sections. Using a 75watt amp at this time which sounds quite a bit bigger than it actually is. Excellent bass , dynamics, and the midrange and highs are well developed and presented. It's not an expensive amp, just a well designed one.

I can't do anemic receivers designed for features and not performance. They always sound dead and lifeless. I share your disgust with modern ultra -end amplifiers which sound sterile. Grating in many cases.

 

[rothwellaudio]

Probably Stereo Review. They wrote the book on everything sounds the same.

There's a link to the original magazine in post #62.
I was a bit confused as to what the methodology used in the trial was, though it seemed quite a thorough trial. I still can't agree with its conclusion though.

 

[Semanon]

There's a link to the original magazine in post #62.
I was a bit confused as to what the methodology used in the trial was, though it seemed quite a thorough trial. I still can't agree with its conclusion though.

Glad I wasn’t the only one confused by the test procedure. While, IMHO, amps have the least impact of almost any device in the audio chain, I agree that there are sonic differences, and different interface effects with different speakers. Clearly noticeable.

 

[ejman]

There's a link to the original magazine in post #62.
I was a bit confused as to what the methodology used in the trial was, though it seemed quite a thorough trial. I still can't agree with its conclusion though.

Interesting they used Magneplanar speakers in the test. My understanding is that these speakers present an almost entirely resistive fairly uniform load throughout the frequency spectrum. Perhaps box speakers with more complex loads would lead to different conclusions?

 

[BilboBaggins]

I got to page two, and have to jump in here because I'm traveling and fading away as I write this.

Hopefully, this has already been brought up. I started off with Celestion Ditton 66s with my first speaker purchase when I returned to audio. I have since had Ditton 22s, 33s, 44s multiple times, and my favorites the 15s. I even have a loner 10 sitting right now in my storage container.

To the OP, if you are driving your Celestion Ditton 25s with anything less than 200 WPC, you have no idea how good they can sound. Period! Let me tell my story, and you will understand how you can save yourself a lot of money, and actually hear those very special speakers at their best. I started on this road when I bought a McIntosh MAC1900. It sounded great and quickly displaced my NAD 356BEE integrated amplifier. However it also showed the limitations of the Bose 8.2 speakers I had bought brand new in the 80s. I wanted more, so I did my research and bought a beautiful pair of restored Ditton 66s. I spent a lot for them, but I wasn't hearing that value. I upgraded to a fully restored Sansui 9090. It didn't do it. You see, I wasn't understanding the complexities of 4 ohm speakers. Which is what I believe your speakers are. Even if they aren't, they are close. They need lots of instant power, and very very few receivers have that. Also, and very important, is they need reserve power, which comes from the capacitors. And the bigger the transformers, the better it will sound. That is what you are paying for in separates. I've had the same with a Kenwood Supreme 500, but it has two transformers.

Just another perspective to consider. Enjoy the ride!