mbriant
Headphoneus Supremus
- Joined
- Jun 21, 2001
- Posts
- 9,538
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- 62
First, let me say that I personally tend to be sceptical when it comes to certain claims made by some manufacturers, retailers, and audiophiles. I, like some others, usually prefer objective measurements to subjective observations. I do still try to keep an open mind however, as I realize that everyone hears differently, some are better trained/experienced as to what to listen for, and everyone listens to a different combination of equipment.
In the past couple of days I've noticed a couple of members who have argued that amplifiers all sound the same and have used the following article written by Ian Masters to support their argument. http://www.mastersonaudio.com/audio/20020901.htm
I know Ian Masters personally. He was a contributing editor for many years, and for a short period, editor of a Canadian audio magazine I used to publish. The editorial team of that magazine were very much in the objectivist camp. I'm familiar with the events and the people he refers to in that particular article. After re-reading what he had to say, it occurred to me that his abbreviated rendition of those various tests which were conducted many years ago, were somewhat misleading as they did not tell the entire story.
I haven't spoken to Ian in 10 years, but still keep in regular contact with a friend and mutual associate, Alan Lofft, who also was a long time editor of the magazine and who worked very closely for many years with Ian Masters. In fact, Alan participated in some of the testing Ian mentions in the article I've linked above. Both of these men have been full-time professional audio journalists and reviewers for several decades. I've witnessed many and even participated in a couple of their extensive double blind listening sessions conducted under strict scientific supervision at the National Research Council in Ottawa. I can say without hesitation that they are serious about their work and they do know their stuff.
After seeing Ian's article being used to "prove" that all amplifiers sound the same, I contacted Alan Lofft yesterday to get some clarification. The following are some excerpts from his correspondence:
Quote:
But here is the crucial part that makes the above comments and Ian Master's article completely inapplicable to the recent headphone amp discussions that have been carried out here during the past couple of days. Remember that when Alan says "My comments", this can also be applied to Ian Master's comments as well ... both these gentlemen participated in that testing and both are in agreement regarding this particular subject.
Quote:
You will not likely find anyone with a more objectivist outlook than Ian and Alan, and yet Alan is effectively saying that with headphone amplifiers at least, there WILL be noticable, audible differences between various amps and headphones.
Again, since Ian's article was being used incorrectly to argue that headphone amps all sound the same, I felt it was important to clear this up. I would imagine that any other articles making similar claims, also refer to power amps for loudspeakers ... not headphone amps.
In the past couple of days I've noticed a couple of members who have argued that amplifiers all sound the same and have used the following article written by Ian Masters to support their argument. http://www.mastersonaudio.com/audio/20020901.htm
I know Ian Masters personally. He was a contributing editor for many years, and for a short period, editor of a Canadian audio magazine I used to publish. The editorial team of that magazine were very much in the objectivist camp. I'm familiar with the events and the people he refers to in that particular article. After re-reading what he had to say, it occurred to me that his abbreviated rendition of those various tests which were conducted many years ago, were somewhat misleading as they did not tell the entire story.
I haven't spoken to Ian in 10 years, but still keep in regular contact with a friend and mutual associate, Alan Lofft, who also was a long time editor of the magazine and who worked very closely for many years with Ian Masters. In fact, Alan participated in some of the testing Ian mentions in the article I've linked above. Both of these men have been full-time professional audio journalists and reviewers for several decades. I've witnessed many and even participated in a couple of their extensive double blind listening sessions conducted under strict scientific supervision at the National Research Council in Ottawa. I can say without hesitation that they are serious about their work and they do know their stuff.
After seeing Ian's article being used to "prove" that all amplifiers sound the same, I contacted Alan Lofft yesterday to get some clarification. The following are some excerpts from his correspondence:
Quote:
| Originally Posted by Alan Loft Mike, by the way, all these tests assumed (and monitored the output of the amplifiers so they never clipped) that the amplifiers were not pushed into clipping or near-clipping and that their frequency responses were flat and linear and distortion measured a fraction of 1%, well below the threshold of detection with music. Of course larger amplifiers will have more reserve in the power supply for dynamic peaks, which is why I always urge people to buy as much power as they can afford especially if they like rock n roll at the levels Ian Colquhoun (edit by MB: Ian Coquhoun the owner of Axiom Audio) and some of my Axiom colleagues listen at well over 100 dB SPL 22 feet back from the main speakers). Jean Poirier, one of our French guys, shut down three Denon 350-watt monoblocs of Ian's. But in our tests, so long as the amplifiers were not clipped, there were no audible differences, even with so-called difficult loads. We had a pair of Quads and the Macintosh tube amplifiers as well, and no differences emerged there. Designing a smooth, wide-band linear power amplifier with transistors or tubes is a piece of cake for a competent engineer because the audio bandwidth is to relatively tiny, just 20 Hz to 20 kHz. Video is a different matter, where high frequencies extend into the GigaHertz range--millions of Hertz. |
But here is the crucial part that makes the above comments and Ian Master's article completely inapplicable to the recent headphone amp discussions that have been carried out here during the past couple of days. Remember that when Alan says "My comments", this can also be applied to Ian Master's comments as well ... both these gentlemen participated in that testing and both are in agreement regarding this particular subject.
Quote:
| Originally Posted by Alan Lofft My comments apply ONLY to loudspeakers driven by well designed transistor or tube amplifiers--the ones that were in the test. Headphone impedances are all over the map, and the potential for interaction with tube output impedances (and resulting changes in frequency response) are great. It's not just slight volume differences that can affect the sound -- although those can be hugely influential -- but tiny frequency response variations. Remember, we can detect 1-dB differences in frequency response in the midrange. |
You will not likely find anyone with a more objectivist outlook than Ian and Alan, and yet Alan is effectively saying that with headphone amplifiers at least, there WILL be noticable, audible differences between various amps and headphones.
Again, since Ian's article was being used incorrectly to argue that headphone amps all sound the same, I felt it was important to clear this up. I would imagine that any other articles making similar claims, also refer to power amps for loudspeakers ... not headphone amps.
