Flat Anechoic Measured Frequency Response Speakers

Jkalman, in my opinion Robert E. Greene of the Absolute Sound (also a high-ranking professor of mathmatics at UCLA) has a genuine understanding of what matters when it comes to a loudspeaker's in-room performance. Here is a link to his website:

http://www.regonaudio.com/

See in particular the measurement supplements to his TAS reviews of the Gradient Revolution and Jamo 909, and the measurements of his Harbeth monitor 40 (that page is currently "under construction" but he has some measurements posted).

The "target curves" that you see in the Gradient and Jamo supplements are similar to a target curve published by Bruel & Kjaer, which I can't find online but it's basically flat below 100 Hz and then slopes down by a little less than 1 dB per octave from there on up. I presume this is a non-time-gated measurement from the listening position.

Duke

Drubin,

You are referring to what Paul Barton said concerning Toole's studies? I've heard that people prefer sizzle on top, not roll-off. Do you have a quote? Thanks.

I think one of the misconceptions about the Toole research was that he trained listners to pick a certain loudspeaker over another. Actually, what they did was to evaluate and train listners to hear various types of distortions added to program material. As well, this was for research purposes, not in any way a marketing ploy to sell a particular brand of loudspeaker.

Also, to add a couple of items to the off-axis dispersion discussion: This is generally accepted to be simply good loudspeaker engineering. Most of the Canadian companies that use the NRC or NRC-based research see this as critical to proper loudspeaker design. But in addition you'll find that Doug Schneider, who assists in the loudspeaker measurements at SS!, and John Atkinson at Stereophile (has measured many speakers), have come to agree that smooth, controlled off-axis dispersion equate with good sound in real rooms.

Lastly, I actually discussed the Athena Project with Paul Barton at CES this year. What they determined was not so much that a midbass bump was desirable, but instead a smooth rise in the bass starting at 200Hz and going down to 20Hz -- I think it was about a 6dB rise over that range. The key being a _smooth_ rise. Anthem is actually basing their new room correction software on this target curve. As for the top end, simply google the EBU target curve and you'll find a good graph.

Hope this helps.

Jeff Fritz
Managing Editor
The SoundStage! Network