Head-Fi.org › Forums › Equipment Forums › Cables, Power, Tweaks, Speakers, Accessories (DBT-Free Forum) › I did a scientific test on a power conditioner--IT WORKS!!!
New Posts  All Forums:Forum Nav:

I did a scientific test on a power conditioner--IT WORKS!!! - Page 2

post #16 of 67
3/2/06 at 12:48am
Quote:
Originally Posted by Ferbose
All amplifiers have internal noise floor.
...
Regardless of S/N ratio, if you lower noise floor by 30%, you increase S/N by 3 dB.
...
The fact that it still benefits from a power conditioner is pretty remarkable, and convinces me that power conditioning benefits I heard are not just imaginations.
But I can't hear amplifier noise without power conditioning. What good does reducing it by 30%, 100%, or 500% do? If you hear noise without power conditioning, your system is not well designed. (Well designed doesn't mean expensive either.)
Reply

Head-Fi's Best Sellers

post #17 of 67
3/2/06 at 2:01am
Thread Starter 
Quote:
Originally Posted by JohnFerrier
But I can't hear amplifier noise without power conditioning. What good does reducing it by 30%, 100%, or 500% do? If you hear noise without power conditioning, your system is not well designed. (Well designed doesn't mean expensive either.)
What you stated is a misconception.

Yes, the noise in your audio systems should be below your listening threshold. In other words, you should not hear speaker hiss at your listening position or hiss in your headphone. But once you play some signal through the system, the noise is added to the signal you hear. Say your signal is a smooth sine wave of 100Hz, and if you add a bit of 5000 Hz noise to it you start to see jagged curves. Even if your ear can not hear the noise by itself, your ear can hear the difference between a smooth 100 Hz sine wave with a jagged one.

Here is a real example. When you make a 24 bit recording and map it down to 16 bit, it is extremely apply dithering (noise shaping) to the last (16th) bit instead of doing simple truncation. Famous dithering algorithms include SBM (Sony), UV22 (Apogee) and K2 (JVC). Can you hear the single-bit signal (0000,0000,0000,0001=-96 dBFS) playing in your CD system? No, unless you turn volume way up. However, when this last bit is a part of the music averaging at -20 dBFS or so, it certainly can make a difference. If noise dithering is not applied to the last bit in CD, the result is harshness, and the loss of detail and spatial information. In fact, with proper noise dithering, you can extend the dynamic range of CD into 18-19 bit (a well known fact to mastering engineers). It is because humans can hear signals below the noise floor, a fact appreciated by LP lovers everyday. Despite the poor measured S/N ratio of LPs, the useful dynamic range is much larger than what S/N suggests, because we can hear signals buried within LP's analog hiss (especially because the noise in LP playback is non-random). In the early days of CD sales, dithering was not as advanced as it is today, and CD sound quality suffered.

You can't hear the digital 1-bit truncation noise being played alone, but it degrades the music you can hear. By the same virtue, even if you can't hear the analog noise of your amplifier without input, it can still audibly degrade your music when there is input.

Do I need to offer a simpler analogy? There are two pieces of white paper, but only one has some faint stain marks. When the room is very dark, you can't see any stain mark and you declare both papers are blank. With better lighting you start to see the difference, and you know which paper is cleaner.
Reply
post #18 of 67
3/2/06 at 2:13am
Quote:
Originally Posted by Ferbose

Do I need to offer a simpler analogy? There are two pieces of white paper, but only one has some faint stain marks. When the room is very dark, you can't see any stain mark and you declare both papers are blank. With better lighting you start to see the difference, and you know which paper is cleaner.
Good analogy. Another one that might be appropriate in this context is when you look at a piece of white piece of paper and declare that it has no color in it. It's only when you compare it to a second piece of paper that is truly white that you see the slight color in the first paper. In other words, I didn't hear any noise in my system either until I did something that reduced it, and then I realized what I was hearing before.

Another example of actual experience establishing that certain preconceptions may be misplaced.
Reply
post #19 of 67
3/2/06 at 2:18am
It depends...in my experience the noise can just be part of the noise floor (i.e. sits at the bottom), but it can also sit on top of your signal. Obviously the noise that sits on top of the signal is more harmful than a slight 3db rise in noise floor. But I would agree that if you have a ground loop or ground noise or other abnormality...its best to *remove* it entirely if possible. I had a ground noise problem that according to RMAA was only in the realm of 3-5 db, but I heard it as added grain while music is playing (that or you'd have to turn up the amplifier very loud to hear the slightly hashy noise floor). Noise that just sits under your signal would be like having a photograph with a few specks in the 'blacks', and noise that sits on top would be a photograph with a few specks anywhere and everywhere.

I'd wonder about more tests such as testing at nighttime listening in a non-lab environment or different housing conditions, etc. Labs are typically full of high voltage test equipment, possibly large motors, etc. Are the power conditions in some subarb going to be the same as a New York apartment etc.
Reply
post #20 of 67
3/2/06 at 2:19am
Quote:
Originally Posted by Ferbose
What you stated is a misconception.
No it's not.

Quote:
Originally Posted by Ferbose
Yes, the noise in your audio systems should be below your listening threshold. In other words, you should not hear speaker hiss at your listening position or hiss in your headphone. But once you play some signal through the system, the noise is added to the signal you hear. Say your signal is a smooth sine wave of 100Hz, and if you add a bit of 5000 Hz noise to it you start to see jagged curves. Even if your ear can not hear the noise by itself, your ear can hear the difference between a smooth 100 Hz sine wave with a jagged one.
Noise that is inaudible without a signal is still inaudible with a signal.

Quote:
Originally Posted by Ferbose
Do I need to offer a simpler analogy? There are two pieces of white paper, but only one has some faint stain marks. When the room is very dark, you can't see any stain mark and you declare both papers are blank. With better lighting you start to see the difference, and you know which paper is cleaner.
You've turned this backwards. A power conditioner does not enhance the ability to hear as light enhances sight. If the stain is not visible, removing 30% of the stain does not make it more visible.
Reply
post #21 of 67
3/2/06 at 2:23am
Quote:
Originally Posted by JohnFerrier
A power conditioner does not enhance the ability to hear as light enhances sight. If the stain is not visible, removing 30% of the stain does not make it more visible.
Are you theorizing, or or have you not had any success with power conditioners in terms of reduction of the noise floor?
Reply
post #22 of 67
3/2/06 at 2:25am
Quote:
Originally Posted by PhilS
Are you theorizing, or or have you not had any success with power conditioners in terms of reduction of the noise floor?
I've got two $1,200 power conditioners in my room. Neither my wife or I could hear a difference.
Reply
post #23 of 67
3/2/06 at 2:28am
Quote:
Originally Posted by JohnFerrier
I've got two $1,200 power conditioners in my room. Neither my wife or I could hear a difference.
Interesting. My experience was quite different, but perhaps my power is "noisy" or something.
Reply
post #24 of 67
3/2/06 at 2:30am
You can both be right. A water purifier could be considered worthless to someone who drinks pure water naturally. Additionally just because a power conditioner is expensive doesn't mean it is well designed either. The Furman unit is produced by a pro-audio/broadcast company and doesn't sell their gear in audiophile circles anyhow. If you are in the broadcast or pro-audio industry...you should probably be buying stuff that 'works' period.
Reply
post #25 of 67
3/2/06 at 2:34am
Quote:
Originally Posted by PhilS
Interesting. My experience was quite different, but perhaps my power is "noisy" or something.
A decently designed audio system will be designed not to have problems with line noise.
Reply
post #26 of 67
3/2/06 at 2:39am
Quote:
Originally Posted by JohnFerrier
A decently designed audio system will be designed not to have problems with line noise.
That's a truism, I think, or it begs the question. Or maybe it's circular reasoning. But whatever.
Reply
post #27 of 67
3/2/06 at 2:41am
Quote:
Originally Posted by Tim D
You can both be right. A water purifier could be considered worthless to someone who drinks pure water naturally. Additionally just because a power conditioner is expensive doesn't mean it is well designed either. The Furman unit is produced by a pro-audio/broadcast company and doesn't sell their gear in audiophile circles anyhow. If you are in the broadcast or pro-audio industry...you should probably be buying stuff that 'works' period.
I don't know what is in the Furnman unit, but the ones I have use a 20 pound torroidal isolation transformer and rather large polypropylene capacitors.
Reply
post #28 of 67
3/2/06 at 2:43am
Quote:
Originally Posted by PhilS
That's a truism, I think, and it also begs the question. Or maybe it's circular reasoning. But whatever.
I know you are confused.
Reply
post #29 of 67
3/2/06 at 2:44am
Quote:
Originally Posted by Ferbose
I actually went into the datasheet of the instrument amplifier and calculated its S/N to be 107 dB.
107 db is about the volume of a car horn at close range. That means that you would have to have your music turned up pretty doggone loud to even get the noise floor to raise above zero. For all intents and purposes, a 30% improvement on 107 (or 104, depending on how you calculated it) is not discernable at normal listening levels.

See ya
Steve
Reply
post #30 of 67
3/2/06 at 2:45am
Quote:
Originally Posted by JohnFerrier
I know you are confused.
Yes, you're too sharp for me. Good night.
Reply
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Equipment Forums › Cables, Power, Tweaks, Speakers, Accessories (DBT-Free Forum) › I did a scientific test on a power conditioner--IT WORKS!!!