I own a pair of ML Summits and still have a lot to learn about audio fidelity. I found your postings on room treatments enlightening, and I was hoping you could clear up some concerns I have about the quality of the Summits that may be reflected in your measurements.
I recently came across Richard Hardesty's
www.audioperfectionist.com online publication where he argues that Martin Logans exhibit poor (quasi-anachoic) frequency responses, poor time and phase performance, and significant energy storage issues that are inherent to their design. He argues that it makes them inaccurate speakers and listeners confuse this with being highly-detailed. DTB300 seems to refer to this effect as "one of the biggest myths in ESL circles -- that the rear wave of the panel provides an "ambiance" that is beneficial to the sound". Hardesty's measurements were taken for a Martin Logan Aerius.
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OK, those are some significant claims, so let’s deconstruct them bit by bit.
First measuring a line array is different than a point source speaker. Measure a dipole Line array (any ML ESL) is even more different.
For line array’s one must be at least a meter away and usually 2 to really capture the full effect of the line source (i.e. the summing of all the drivers, or the entire panel).
And at 2m, the room is providing a big influence on the measured response.
Now, since any line source will be >4’ tall, the mic will be picking up signals from varying angles emanating from the speaker, this will show up as some comb filtering on the frequency spectrum. But the benefits of a deep soundfield plus an even energizing of the room at mid and low frequencies (for line arrays of dynamic drivers) provides greater benefits than penalties.
My tests of the SL3 panel (a new one in my center) shows they have excellent time response, and the phase is not an issue either. If you do no absorb the rear wave, then yes, there can be all kinds of issues. But then those are room induced and not inherent in the speaker.
As for ‘energy storage’ I’m not buying that, as an ESL has vanishingly low mass in its diaphragm, so where is this ‘energy’ being stored?
Now, A bad panel element can resonate (or buzz) if the spars are not set right or the tension in the mylar is off. But then so can a cone driver that’s not well attached to its voice coil. Spurious claim in my book ...
So fundamentally, a good ESL is a very accurate transducer, much more so than cone drivers that’s for sure.
The challenge, as this entire thread is trying to address, is how they will operate in the various listening environments we put them in.
There I’d agree that just plopping the speaker down and hooking up the amp will yield measured responses that do feature problems we’ve been documenting here.
The good news is they can be dealt with.
My question is whether you know of any published quasi-anachoic response measurements for the Summits? Whether the Summits perform as poorly on the speaker response tests as the Aerius? And if so, whether it's best to start with a better (anachoic) performing speaker in the first place before investing in room treatments or any other improvements?
I guess ultimately my question is whether room effect treatments can overcome speaker performance deficiencies? Or are room effects so much more important than speaker deficiencies among “decent” speakers that fixing room effects has a bigger incremental benefit than starting with better performing speakers?
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A good performing speaker is an important starting point, but ideal anechoic is not necessarily required. Because as I’ve been documenting, the in-room response is affected by the room to such a large extent, that how the speaker is designed to interact with the room is just as important (if not more so) as good anechoic numbers.
The ‘deficiencies’ of speakers are many. For instance box resonances, the non-linear effects of acoustic suspension alignments, port resonances on ported speakers, horn directivity and ‘glare’ issues with horns, and of specific interest, the management of dipole radiation from Maggies, ML’s, Soundlabs, etc.
The question is: how are they managed and how do they interact with a room?
Good design mitigates many of them, but room interface is critical. These are mostly under user control and therefore subject to huge variations.
So my bottom line is that any pair of good speakers will still face a huge challenge as we try and interface it to a room. No one design is a winner in all cases.
We just pick our favorite compromises and deal with them
