May 23, 2005

Even though it's still a rarity to find a time-coherent loudspeaker, more and more of them are appearing. Meadowlark, in particular, says that time coherency is the most important thing a speaker should do!Q: Yet, you don't show the step response in your measurements. Why?

John Harnick

A: The benefits of time alignment are highly debated, with designers residing on both sides of the fence. As for it being the most important criteria over, say, reasonably linear frequency response or low distortion, this is questionable.

I don't think it's true, though, that we're seeing more and more designs that are time coherent, or even claimed to be time coherent. There are only a limited number of manufacturers producing truly time-coherent speakers -- Thiel is probably the largest of this group. And in my discussions with Jim Thiel, I discovered that he places a strong emphasis on time coherency, but not at the expense of other important objective standards. Take a look at the measurements of a Thiel loudspeaker and you'll see that.

As for why we don't include step response in our measurements, or even some other measurements that can add benefit to discern how a speaker will perform, the answer is simple: time and money. The way we do our measurements -- in an anechoic chamber with laboratory-grade equipment and with independent staff -- is costly and far beyond what any other publication is doing. Any additional measurements take more time and cost more money. We have to draw the line somewhere.

However, that's not to say we won't add measurements. In 2006 I'd like to see our measurement program expand, and we hope to include step response and other measurements. When we do, we all might learn that many manufacturers that claim time coherency may not meet that standard, just as today many that claim a certain sensitivity figure or level of linearity often don't measure up.

...Doug Schneider