Audio Research and Martin Logan Montis

"03-06-15: Georgelofi

03-06-15: Zd542
What difference does it make if the system sounds OK?

What about a different speaker like the Prodigy? Would you say the same about that one?

Well your not listening to a flat frequency response, it like having a fix tone control embedded, + - 4db from 20hz to 20khz"

In order to have a situation like that, some pretty big assumptions have to be made. All the other components in the system, including the room will have to be neutral and deliver a frequency response that is flat, in order for that one issue listed above to manifest itself as a specific problem. By the time you're done picking matching components and setting them up in any given room, another component could balance the imperfection in the FR out, or even make it worse. None of this happens in a vacuum. Its a challenge getting all the components in a system, set up and working well, given they're flaws as well. Not to mention, planer speakers, in general, don't measure well to begin with. They never have and its something you really have to accept when you buy them.

The reason I asked about the Prodigy was was that, when it first came out, I was invited by my dealer to attend the new product seminar that ML gives when a major product is released. I'm not sure if they do this for all dealers, but the one I used to go to was very big and did a lot of volume. At the seminar, they selected some components in the store to do the setup, and the ML rep. (Gayle Sanders), picked an ARC VT-100 to power them with. He could have chosen anything. The store had no shortage of big, powerful solid state amps. And the Prodigy looks to be a much more difficult load than the Montis that we're talking about here. So, if an amp like that is OK for the guy who designed the speakers, I'm OK with just leaving it at that. But that's my own personal decision, and I won't try force it on anyone else. To be fair, I've heard ML sound great with Krell, Threshold/Pass, Counterpoint, McCormack and ARC solid state amps. There's no shortage of good choices regardless of personal preference.

All I can say to that is, "why do all equipment manufactures strive for a flat response?" And give +-db frequency response measurements points in their specifications?

If they wanted to have it altered all over the audio spectrum because of external loads, they wouldn't be bothered to list those specs to start with.

Need to look at the graphs closer, as the Montis is the harder load as it's bad phase/load point is at 4-5khz (the presence region), the Prodigy is up much higher at 7-10khz, as for the rest of it down low, it is a benign 4-6ohm load, with no - phase shifts to add to it.

Cheers George

hi everyone,
I have an opinion about the above technical aspects which senior fellows here were discussing. I have no electrical background but wish to express something which maybe important and overlooked.

We had seen many varieties of impedance coupled with varying phase angles charts, especially from ESL speakers when they behave like a giant cap into high freq.
When some audiophiles describe tubes amp suit well for ESL, we are assuming the tubes would handle the voltage & current needs well, at a certain range of frequencies. because, generally tubes cannot provide enough high current into magnetic coils when required for high excursion of speaker drivers into low bass.

Now, I do not know how tubes behave given the ever changing phase angle in relation to impedance,(voltage leads or lags before/after the current), but I suspect that tube can offer more "fluctuation" or "more tolerant" to out of phase signals when required by the speaker to produce music. I believe tubes are naturally more "forgiving"(tubes can give more voltage without rising current) as compared to output transistors when facing these out of phase requirements posed by speakers, especially ESLs. I guess transistors usually have a tighter range to work with electrical signal. transistors are generally linear devices am I right? my bet is that transistors work best when voltage and current are output simultaneously(meaning linear), to provide the power needed by speakers, so if transistors need to work beyond its specification(non-linear), it would clip even before it reaches its full rated power(watt).

base on above assumption, I perceive that tubes would better suited for ESLs but there are caveats, that's the songs the listener is playing should not contain low bass & high notes i.e. no punching bass, no high pitch like triangles or in harps/flutes etc.. (please also bear in mind tubes are slower in response, transistors are faster)

just my two cents.