Monolith FR: where is the truth?

I have seen various reviews of Monoliths where is stated that they are a "bright" loudspeaker (stereophile - http://www.stereophile.com/floorloudspeakers/385ml/ , Dr Dave impressions - http://www.martinloganowners.com/forum/showthread.php?t=6553 , etc), but my feeling is that it is just the opposite.
I've made a measurement and I've found out that from 1-2kHz the response starts to drop to almost 8-10dB less at 8-10kHz, rising then near the 1kHz level on a peak about 15kHz.

Please note that now my room has very little absorbtion...

I started worrying about my new panels, but then I found a message from Jonathan where he found the same frequency reponse.

So, where is the truth?

Ciao!

Paolo

revealing, yes, but not bright to me

Ciao Paolo!
I haven’t had but one occasion when the Monolith IIIs' freq response was measured. (I’m not sure if a newly replaced panel is the same or different between different versions of the Monolith and I use active x-over). The guy who has done the measurement (used pink noise) said that he hasn’t seen such flat response from too many speakers lately – at least regarding the mid to high frequencies.
But then again, even if done by a pro, it was only one fairly quick snapshot.

I have one diffuser behind each panel and one in between (each of them are almost the size of the panels). I will switch these to absorbers; tried it and the results were better – and will probably keep the diffusers in the middle or try them on the ceiling (subject to WAF).

Though that time I had a preamp and cables about two-three classes inferior to what I have today, I have never found the Monoliths to be bright. Revealing, yes, but not bright; there are a few crappy recordings that can sound harsh but these are equally scratchy when listening to on headphones.

I’m not sure if an absorber / diffuser behind would be a cure for this, but it is most probably worth trying. You can ask a pair of friends / family to hold a thick blanket (or blankets) about 1 meter behind the panels (if you have that space behind) and see/hear for yourself. It will almost certainly alter the sound, but for me the change was more in depth and clarity of the sound, not in brightness.
Use the first few minutes for critical listening as the 'blanket frames' might start complaining after a while…

What about the equipment and cables?
Have faith; it’s a tedious process; Im wondering sometimes if it is about the journey or the destination. Good luck,
M

pidigi said:

I have seen various reviews of Monoliths where is stated that they are a "bright" loudspeaker (stereophile - http://www.stereophile.com/floorloudspeakers/385ml/ , Dr Dave impressions - http://www.martinloganowners.com/forum/showthread.php?t=6553 , etc), but my feeling is that it is just the opposite.
I've made a measurement and I've found out that from 1-2kHz the response starts to drop to almost 8-10dB less at 8-10kHz, rising then near the 1kHz level on a peak about 15kHz.

So, where is the truth?

Ciao!

Paolo

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Martin Logan has always been tainted with the "bright" label. In some cases it's the upstream equipment. In other cases, it's just reproducing the music, which may be "bright". To me it just sounds real.

Hi!

Thanks for your help, guys!

First of all I have to say that I don't think that my Monoliths are bright, actually I expected them to be much brighter after panel replacement. And this is the point, I don't know if now they are performing as they should or not. You know, they are really old, so maybe there could be something else wrong.

Here is JonFo's post about frequency reponse (similar to my results):

http://www.martinloganowners.com/~tdacquis/forum/showpost.php?p=76684&postcount=117

as you can see it drops after about 2kHz quite a bit... can you confirm that Jonathan?

I know that it is not easy to have a correct measurement on a dipole speaker in a not anechoic room, but since this is in line with what I hear....
I think that using absorbers I would end up having, apart from the benefits we all know, an overall less bright sound, wouldn't I?

Ciao!

Paolo

David Matz said:

Martin Logan has always been tainted with the "bright" label. In some cases it's the upstream equipment. In other cases, it's just reproducing the music, which may be "bright". To me it just sounds real.

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Agreed David and also the fact that ALOT of folks do not know how to set-up / position a pair of dipole electrostatic speakers.

David Matz said:

Martin Logan has always been tainted with the "bright" label. In some cases it's the upstream equipment. In other cases, it's just reproducing the music, which may be "bright". To me it just sounds real.

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That is the Key with Hybrid Logans. The CLS are not bright but can be as bad with poor upstream gear!

twich54 said:

Agreed David and also the fact that ALOT of folks do not know how to set-up / position a pair of dipole electrostatic speakers.

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Set up with Hybrids is KEY! I can say it has to be to the nines, and the room better be treated a bit if its a tad bit live!

I don’t find my Monolith III bright at all. I can listen for hours at a good level with no fatigue. I do find it very detailed and transparent but not bright. I think my up stream equipment (CJ premier LS16 pre and Premier 350 amp) have a lot to do with keeping the sound warm.

I do not really like most reviews

you could dry out most reviews and use them to fertilize your lawn in my opinion. I would not put much stock into what dr. dave has to say

In a moment . . . . .

FISH_MAN said:

you could dry out most reviews and use them to fertilize your lawn in my opinion. I would not put much stock into what dr. dave has to say

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One of the most magnificent witticisms from the arts was by German composer Max Reger (1873-1916). Responding to a negative review by Rudolf Louis of his Sinfonietta (1906), Reger is said to have shot back: "Ich sitze in dem kleinsten Zimmer in meinem Hause. Ich habe Ihre Kritik von mir. Im nächsten Augenblick wird sie hinter mir sein." (I am sitting in the smallest room of my house. I have your review before me. In a moment it will be behind me.)

nsgarch said:

One of the most magnificent witticisms from the arts was by German composer Max Reger (1873-1916). Responding to a negative review by Rudolf Louis of his Sinfonietta (1906), Reger is said to have shot back: "Ich sitze in dem kleinsten Zimmer in meinem Hause. Ich habe Ihre Kritik von mir. Im nächsten Augenblick wird sie hinter mir sein." (I am sitting in the smallest room of my house. I have your review before me. In a moment it will be behind me.)

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Great stuff, Neil! Next time I get a review I don't like, I will use that language with my boss.

In all fairness, though, the stereophile review is written by maybe the best reviewer ever - J. Gordon Holt. Should it be the only source of information without listening? No! If it is, then one is a dumb ass. However, it is extremely valuable to get some information from experts, even if the experts are a bit biased and over confident of their abilities.

Reading it, however, it is a review of the amps he is using as much as the speakers. My takeaway (and I am biased) is that the Monolith is a great speaker that needs a great amp. The CJ 350 that Cherian mentions (also owned by myself and Tonepub) is one such amp. By the way, a BIG thanks to Tonepub (a reviewer!) for steering myself and Cherian toward the amp. Monolith mated with a high quality preamp and source would make one hell of a system. Having heard Cherian's system, I am speaking from experience.

Hi Paolo,

As the measurements suggest, the panels on the Monolith roll-off pretty rapidly above 4Khz. So I’d not characterize them as ‘bright’.

What I think many people are experiencing when they report that condition is a large amount of early reflection energy reinforcing the 3 to 8Khz range.
I know that as I’ve treated my room over the years, this an area that has steadily improved, and the ‘balance’ of the highs has become much better.

Treating the room with a focus on mid-bass and midrange helps resolve the obvious room-induced modes at those frequencies, and most traps also will absorb at the higher frequencies, but surprisingly, not as much as one would think. The ML panel is capable of putting out an extraordinary amount of HF energy.
So absorbing the rear wave of that energy translates in less early reflection interference /reinforcement (i.e. comb-filtering) and generally gives a much more pleasant sound.

Rememeber that if looking at 1/3 rd octave smoothed frequency response graphs, you are missing a lot of the details, such as the HF comb-filtering one sees on a Bode response plot.

Also, a FR plot does tell you everything about a speakers sound, so use with caution.
The impulse response graph is useful for seeing the early reflection issues in their time-domain, and it’s possible to deduce how to change placement or treatment to remove clearly detected reflection issues.

Just for grins, here a 10-point average Audyssey Pro measurement of my left front Monolith:


This is with no EQ whatsoever, and using an electronic crossover (the DBX). So that is the (almost) natural roll-off of the panel, in-room. I say almost, as I’m running 1-Ohm resistance in series with the panel by using the Voltage source outputs of the Sunfire amp. Driving it straight would bring up the response around 10Khz by 3 to 5 dB.

But even Audyssey target curves feature a roll-off in the HF and even a dip in the 3Khz range, as being what is most effective in small-room situations.
So the natural curve of this Monolith is actually sort of what you want anyway in the HF.

Thanks!

Thank you all for your help!

Neil, I like very much your story about reviews!!!

David, thanks for your suggestion, I'll do my best to mate my Monoliths with proper electronics. Actually I'm a DIYer, so I should say that I have to design and build somethink that can keep up with them! At the moment I drive them with a 2x160W mosfet amplifier, I'm quite happy with it, but I'm thinking about a high power tube amplifer for the panels, I have to see where the biamping path can lead me.... Anyhow, the CJ350 is out of budget

Jonathan, thanks again for your valuable help. I feel better now that I know that my measurements really match with yours. I'm planning to start a thread about the right way to read an fr and an impulse response graph, most of all for the informations about room treatment, but I have some problems now in obtaining a picture from my measurement gear...
But why do you use a 1 ohm resistor in series with the panels? It should reduce further their high frequency efficiency....

Ciao!

Paolo

pidigi said:

...
But why do you use a 1 ohm resistor in series with the panels? It should reduce further their high frequency efficiency....

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Paolo, since my Monoliths are driven direct (no passive x-over) it is essentially the amp hooked up to the ESL step-up audio transformer. And in this situation, it's often recommended to have a bit more resistance in the circuit to ensure amplifier stability. Some amps will actually distort and oscillate into a pure reactive / capacitive load such as the ESL + transformer.

My Sunfires are pretty stable direct, and have a bit more 'warmth' using the resistance, as it also is part of the tuning process for an ESL step-up circuit.

When used to tune, It is known as Rep, and is tuned with values ranging from 0.25 to 2 ohms. What it does is it dampens high-frequency ringing in the circuit.

This spec doc on the amplimo step up transformers discusses Rep a bit.

HF efficiency is impacted a bit, but it is cleaner than without.

It's been said, many years ago, by non other than RCA's Harry Olson that perfectly flat response isn't necessarily desirable. And acknowledged by many others since. More on HO credentials here....

http://en.wikipedia.org/wiki/Harry_Olson

That said, my Monolith's measure to be pretty flat in my room. They also compare very well to many others that have been in there. I don't think their response is tilted up or down. Nor do I attempt to defeat the dipolar pattern with total rear wave absorption. And my pair have the original panels and likely are some of the oldest around. Approaching what...about 25 years old.

Bob Carver himself, last week at CarverFest, discussed adding resistance that way. He said it was the biggest key to the matching of his SS amp to the Conrad Johnson in the Stereophile speaker challenge. He said that adding the small value of resistance can get you about 90% of the "tube" sound and recommended people try it and see if they liked it in their situation.

OldMonolith