Originally Posted by JonasHansen
Now that you mention "comparing electronics", what are you experience with audible differences between amplifiers? Harman pairs the M2 speakers with both Mark Levinson amplifiers and Crown amplifiers in different price ranges. All these amps should have sufficient power to be well below the clipping threshold, but will they sound the same?
I discuss the matching of power amplifiers and loudspeakers in Part 3 of the series on designing home theaters on the open access (free!) companion website for the third edition of my book. www.routledge.com/cw/toole
. Click on the topic at the top of the webpage and download.
Obviously sound levels need to be well matched - not necessarily to within 0.1 dB as has been suggested. Hearing a very small difference in level may or may not translate into a difference in preference. It might conceivably happen in electronics, because the frequency responses are usually ruler flat, but it is highly unlikely in loudspeakers, as discussed in a recent post. The dominant factor in any level mismatch is the rapid growth of loudness at low frequencies. That could keep a thread going endlessly unless the tests are double blind.
I did my first power amplifier comparison in the mid 80s, for a serious Canadian audio magazine (remember when they existed?). Using the extensive facilities of the NRCC they were compared when driving dramatically different loudspeaker loads (in an adjacent acoustically isolated room), oscilloscopes monitored waveforms watching for clipping, and all of the sound was monitored using the same loudspeaker and power amp driven by the voltage across the "load" loudspeakers - these were constant factors. To everyone's amazement there was no significant difference perceived by the experienced audiophiles who participated. There were no time limits. Making it even more amazing was that nobody detected a true class B contender - until we played the pure tone sweep used for calibration which revealed the crossover distortion mercilessly. Simultaneous masking is powerful. A few other tests were similarly disappointing to those claiming large easily audible differences.
In the process some audible problems were revealed - all of them related to voltage or current limiting or misbehaving protection circuitry. I address these in the website article.
Fast forward to a few years ago and with the appearance of "digital" pulse-width modulated power amps there was an upsurge of resistance from the traditionalists. To be sure, there were products with problems, but there were others that exhibited no measurable, and, as it turns out, no audible problems so long as the current and voltage limits are not exceeded. One of these tests involved some analog power amps with prices that bring tears to the eyes - not all Harman - but with spectacular reputations. The results of protracted listening by self admitted purists yielded a statistical draw. The most golden of ears we were able to recruit found the "digital" amps to be just fine. They were, in this case, Crown amps.
Now I am not claiming that all digital amps are as good, or that Crown amps are the best, but merely to suggest that the relatively common concern about non-analog amplifiers is usually unwarranted. Remember, there were, and very likely still are, both "digital" and analog amps that fail to meet expectations. Think "receivers". Personally, I am listening to a mixture of both technologies.