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Magico M2

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Posted on January 10, 2020 at 08:49:23
mark.korda@myfairpoint.net
Audiophile

Posts: 1253
Location: Maine
Joined: August 16, 2011
 Hi,
When I read John Atkinson's review I learned something new I never read in any book before. It was from Magico's Alon Wolf. He stated in simple terms why a sealed speaker system out performs a bass reflex system. One thing he mentioned was the extra (oomph) at 60 hz in a bass reflex speaker enclosure.
Great job JA! In your interview you dug out much more info than writing down adjectives that a dummy like me has to look up in a dictionary.
But, on JA's measurements there is a bump at about 60 hz in the measured frequency response. There was an explanation by John Atkinson but I didn't fully understand it. I think it had to do with the enormous weight of the speakers and where the testing was being done. I know John has tested audio heavy weights before so is this bump a regular thing with other back busters?
Thanks for any info and as God and my first grade teacher Mrs. Quinn as my witnesses I made at least 5 indented paragraphs.If this question comes out in one big one I'm sorry. It's not my doing.
The last Feb. Stereophile was packed with great articles by all writers and to me was an important learning tool issue for me....
Sincerely, Mark Korda.

 

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RE: Magico M2, posted on January 10, 2020 at 09:00:27
Coner
Audiophile

Posts: 3703
Location: S.W. Washington state, USA
Joined: November 17, 2001
 Hmmm...and that's a great feature?. Many cheap speakers and
most PA monitiors have a peak 50-60 Hz, so seems like a really
stupid design for a home speaker. Outperform a B.R.? Not at
60 Hz.!.

 

RE: Magico M2, posted on January 10, 2020 at 09:54:52
Inmate51
 Link?

All I know is that, as a musician and recording engineer, when I heard the Magico S7 in their listening room, it was one of the best speakers I've ever heard.

Reviewers may disagree.

 

AFAIK, a 60 Hz bump would totally depend on damping (Qtc), posted on January 10, 2020 at 10:10:09
mhardy6647
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  Since: October 23, 2016

An underdamped loudspeaker system (Qtc > 1, or thereabouts) will certainly have a low frequency response peak.

All things being equal (proper matching of woofer parameters and enclosure design), the big difference in sealed vs. ported enclosures, I think, is in the rate of low frequency response rolloff (EDIT 12 dB per octave for a sealed 'acoustic suspension' alignment, vs. EDIT 18 dB per octave for a ported alignment (Helmholtz resonator).

I mean, I'm a biochemist, not a loudspeaker designer (dammit, Jim!) but that'd be my understanding.


all the best,
mrh

 

As JA explains in nearly every speaker review:, posted on January 10, 2020 at 11:20:12
Brian H P
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Posts: 1291
Location: Oregon
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 "The woofer's output has a slight peak in the upper bass, which will be due in part to the nearfield measurement technique, which assumes the drive-unit is firing into half-space rather than in all directions."

So a SLIGHT bump just above the LF cutoff, measured nearfield, correlates with a FLAT farfield response. When such a bump does not appear in the nearfield measurement, as is occasionally the case, JA usually notes an overly lean bass response in the farfield, sacrificing extension for tautness.

As for the alleged superiority of sealed over bass reflex loading . . . it depends. BR exhibits more phase shift and group delay at the low end, but when properly implemented can extend quite low and flat without boominess. It's just harder to properly implement -- more math involved -- and port resonances may become another issue if not properly dealt with in the design.

Sealed alignments are much easier to calculate, and more forgiving of slight errors, since all the Qtc values are points along a continuum. And, as mhardy notes above, sealed speakers can also be made to boom above cutoff, just by using a smaller box to achieve a higher Qtc.

 

re: boomy sealed boxes..., posted on January 10, 2020 at 12:46:55
mhardy6647
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  Since: October 23, 2016


-- as a decade's worth of "Kabuki" style loudspeakers mercilessly demonstrated ;)


all the best,
mrh

 

Sealed-vs-ported designs and nearfield measurements, posted on January 10, 2020 at 15:33:20
Jim Austin
Reviewer

Posts: 71
Location: New York
Joined: March 11, 2019
 I recommend that you (and others) read JA's description of how he measures loudspeakers--especially the part linked below, in which he covers this terrain, including the correction for near-field measuring. Link appended.

Jim Austin, Editor
Stereophile

 

re: "-- as a decade's worth of "Kabuki" style loudspeakers mercilessly demonstrated ;)", posted on January 10, 2020 at 15:52:41
Krav Maga
Audiophile

Posts: 2351
Location: Texas
Joined: October 19, 2017

I wonder how they would sound playing this "Kabuki" group. :-)
"All thoughts are prey to some beast" - Bill Callahan

"I'll be your mirror
Reflect what you are" - Lou Reed

"Blind belief in authority is the greatest enemy of truth." - Albert Einstein

 

RE: As JA explains in nearly every speaker review:, posted on January 10, 2020 at 20:36:35
hahax@verizon.net
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Posts: 4306
Location: New Jersey
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 The best bass reflex ALWAYS has more overhang than the best closed box speaker. Some people like it but it is less accurate. Bass reflex is more efficient than closed box. And it is easier to extend the point a good reflex design starts rolling off. But at some lower point due to 12dB/octave roll off of closed box, versus 24 dB/octave of reflex the reflex bass, closed box bass will be higher then reflex.

 

re: boomy sealed boxes..., posted on January 10, 2020 at 20:38:14
hahax@verizon.net
Audiophile

Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 bad closed box design is boomy. bad reflex design is even boomier.

 

RE: AFAIK, a 60 Hz bump would totally depend on damping (Qtc), posted on January 10, 2020 at 21:37:39
hahax@verizon.net
Audiophile

Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 Sealed and acoustic suspension are not the same. Acoustic suspension is sealed. Sealed does not have to be acoustic suspension. In a set theory sense acoustic suspension is a proper sub set of closed box.

For a closed box a Q of 0.5 is optimally damped. A Q of 0.707 is flat. Anything over 0.707 is under damped, that is it has a bump in the bass.

 

Bass Reflex vs. Closed Box, posted on January 10, 2020 at 22:30:21
Inmate51
 "The best bass reflex ALWAYS has more overhang than the best closed box speaker."

True.

Please cite two examples of the best of each. Include valid measurements.

 

RE: Bass Reflex vs. Closed Box, posted on January 10, 2020 at 22:55:17
hahax@verizon.net
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 closed box, any Magico is closed box with low Q. Also the ATC 19, both passive and active. There are a few others like YG but closed box designs are rare because good ones don't sound bassy like many reflexes and they are more efficient than closed boxes(about 3 dB).

Damn near everything today is bass reflex. This includes speakers like Golden Ear which have no port but have a passive radiator(speaker without voice coil) which acts essentially like a port.

Probably the best bass reflex speakers are the Rockports which roll off like a closed box for one octave and then act like a reflex. But they are an example of one. Otherwise pick your favorite reflex box. It may sound nice but it has overhang and if you like the sound you like bass ringing. It can be tuned nicely(in a few cases) but it's merely a pretty coloration.

 

Eh, you can choose your Q with either approach, posted on January 11, 2020 at 06:07:47
Dave_K
 And the ideal Q is very much room dependent. If the resonance frequency is close to a room mode, you'll appreciate a lower Q. If the room has rigid walls and no bass absorption, you'll probably want critical damping, whereas if you have a lot of bass absorption or the resonance frequency is close to a null in the room response, you might want a little higher Q.

There's less phase shift and lower group delay with a sealed alignment, but most people think that phase shift is inaudible in the bass range (if at all).

 

RE: Eh, you can choose your Q with either approach, posted on January 11, 2020 at 07:35:45
hahax@verizon.net
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Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 Transient wise lower Q is always more accurate for both closed box and reflex. The price may be leaner bass balance. But closed box always is ultimately better damped in the bass and thus always more accurate reproduction.

 

RE: Eh, you can choose your Q with either approach, posted on January 11, 2020 at 12:49:14
Dave_K
 Lower Q is not always better. Most of the time, the ideal Q will be near critical damping plus or minus a little bit, but it depends on the loudspeaker and room and to some extent the listener too. Designing for a Qtc that's too low won't improve transient response, it will blunt transients. Overdamped bass doesn't sound natural

Since you can design either type with a high or low Q, your argument that sealed box is always better damped just isn't true at all.

 

RE: Eh, you can choose your Q with either approach, posted on January 11, 2020 at 14:21:40
hahax@verizon.net
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Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 Over damped is a Q less than 0.5. No one makes a speaker with a Q under 0.5. Almost no one makes a speaker with a Q even at 0.5. My argument is that given a well designed closed box and a well designed reflex the closed box has less overhang than a reflex. This is true. Every real designer knows this. Over hang is distortion.

If a reflex speaker sounds 'better' then it is either because the input has been recorded poorly or the listener likes over hang, distortion.

 

even worse ;) (nt), posted on January 11, 2020 at 18:53:51
mhardy6647
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  Since: October 23, 2016
 nt


all the best,
mrh

 

RE: Magico M2, posted on January 12, 2020 at 02:08:54
PAR
Audiophile

Posts: 1732
Location: South London, UK
Joined: June 4, 2019
 I just thought people may be interested in Magico's own measurement of the M2 using a technique involving a robot that I have not come across before.
"We need less, but better" - Dieter Rams

 

RE: Magico M2, posted on January 12, 2020 at 14:12:20
mark.korda@myfairpoint.net
Audiophile

Posts: 1253
Location: Maine
Joined: August 16, 2011
 Hi, thanks for all your answers. For me I think PAR with that picture was the easiest to understand. I don't know what John Atkinsons measurement area looks like or if he just uses his listening room but I still would like to know why similar sized speaker heavyweights he tested did not show the 60 hz bump in the frequency graph.Thanks again,you guys gave me a ton of info.....sincerely Mark.

 

RE: Magico M2, posted on January 12, 2020 at 15:10:12
John Atkinson
Reviewer

Posts: 4045
Location: New York
Joined: November 24, 2003
 >I don't know what John Atkinson's measurement area looks like or if he just
>uses his listening room but I still would like to know why similar sized
>speaker heavyweights he tested did not show the 60Hz bump in the frequency
>graph.

The 60Hz "bump" in my response measurement is entirely due to the nearfield
measurement technique, which assumes the drive-units are placed on a true
"infinite baffle," ie, one that extends to infinity in both planes. You can
see similar behavior in all my loudspeaker measurements. In an anechoic
environment, the Magico M2's low frequencies will be flat, rolling off below
the woofer tuning frequency.

John Atkinson
Technical Editor, Stereophile

 

yes, I know... I mentioned both trying to differentiate them, but was too elliptical, posted on January 12, 2020 at 19:17:09
mhardy6647
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Posts: 16015
Location: New England
Joined: October 12, 1999
Contributor
  Since: October 23, 2016
 sorry.

There are of course sealed box alignments that aren't acoustic suspension -- the infinite baffle being the first that comes to my mind.


all the best,
mrh

 

RE: Eh, you can choose your Q with either approach, posted on January 13, 2020 at 13:17:29
Dave_K
 As I keep saying, you can achieve the same Q with either alignment. Sealed and ported loudspeakers are both resonant systems with a single peak whose parameters are up to the designer. You can design a bass reflex loudspeaker with Qtc=0.5 and sealed loudspeaker with Qtc = 1.0 if you want to. Or vice versa.

I misspoke. When I said most designs aim for close to critical damping, I was actually thinking of Qtc around 0.7, closer to maximally flat than critical damping. Professional designers tend to aim for the same Q regardless of enclosure type, because they are making generic designs for any room. But if you have knowledge of your room gain and room modes, you could make a more optimized choice with either enclosure type.

"Overhang" is a meaningless term. What specifically do you mean by that? If you're talking about phase shift/group delay, that will be greater with bass reflex, but most people have concluded that phase shifts are not audible in the bass, if anywhere. If you're talking about the tail of the impulse response, that's dependent on Q.

 

RE: Eh, you can choose your Q with either approach, posted on January 13, 2020 at 20:34:10
hahax@verizon.net
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Posts: 4306
Location: New Jersey
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 You are incorrect. Reflex has 2 impedance peaks, one for the box and one for the port. Closed box(or the rarely used variovent, highly stuffed port that has essentially no acoustic output) has only one peak. Because of this reflex rolls off at 24 dB and closed box at 12 dB. Thus reflex has more overhang and the best reflex can NEVER be as well damped as the best closed box. No amount of design can compensate for the differences a port makes. The only one I know that comes close is the Rockport design and I've spoken with the designer and it is proprietary.

 

RE: Eh, you can choose your Q with either approach, posted on January 14, 2020 at 21:34:06
Dave_K
 Bass reflex has two impedance peaks, but only one resonance. Both sealed and reflex have a single resonance with the Q up to the designer.

Bass reflex rolls off 4th order below resonance, vs. 2nd order for sealed, but that's not relevant to your argument.

The simple FACT is you can design either enclosure to have an over-damped or under-damped resonance, as you choose. There is no rule of physics that insists sealed will always be more damped than ported. Nor would you want that because more damped != better.

As for "overhang", it's a meaningless audiophile term. If you can put your argument in technical terms we could have a discussion.

 

RE: Eh, you can choose your Q with either approach, posted on January 15, 2020 at 01:17:55
hahax@verizon.net
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Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 overhang is simple, it's continuing to move after signal is removed.

what is reflex? Is it different from bass reflex? I have never heard the term. Is it different from bass reflex?

and yes there are rules that say ported has poorer bass control than closed box. It is simply due to the faster roll off of bass reflex. closed box rolls off at 12 dB/octave. Bass reflex rolls off at 24 dB/octave, 12 dB from box roll off plus another 12 dB from the port roll off.

By the way, Q is conventionally used in reference to closed box. When referring to bass reflex the term is bass alignment.

You really should read a book on bass box design. Try The Loud Speaker Design Cookbook by Vance Dickason. It has relatively simple descriptions of closed box design and bass reflex in the intro to the chapters on each format.

 

RE: Eh, you can choose your Q with either approach, posted on January 16, 2020 at 09:34:09
Dave_K
 By reflex I meant bass reflex. I omitted the "bass" for brevity because I was banging out that post on my phone.

And I hate arguing semantics, but Q is a universal measure of how damped a resonant system is, in any application. In loudspeaker design, regardless of whether you're working with a sealed alignment or bass reflex alignment, the most important parameters to characterize the design are fs and Qtc. Together, those two parameters fully describe the total system resonance including the enclosure, regardless of enclosure type. The term alignment is used when discussing all enclosure types. I don't know that I've ever seen a precise definition, but I believe it is an umbrella term used to refer to a specific box tuning.

You said overhang means continuing to move after the signal is removed. From that I infer you're talking about impulse response. Every resonant system responds to an impulse with a decaying oscillation. An impulse response with a longer tail = more cycles of oscillation = more overhang. Does that fit your definition? If so, then I'll reiterate one more time that all you need to know is the resonant frequency and Q. The decay rate of the impulse response tail *is* Q.

Bass control is another subjective term. To me, good bass control means an absence of any significant bass peaks in the frequency response, combined with well damped bass. Both acoustic and electrical damping matter. I don't know what bass control means to you, but I can't imagine how you relate it to roll-off.

 

RE: Eh, you can choose your Q with either approach, posted on January 16, 2020 at 20:35:03
hahax@verizon.net
Audiophile

Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 Wrong, as I said and is well known reflex rolls at 24 dB/octave and closed box at 12 dB/octave and because of this reflex bass continues as a resonance longer than closed box bass. Please read any book on bass box design.

Or go to the SB Acoustics web site. Go to links, the SpeakerBuilder Pro. You can calculate bass response for SB woofers for both closed box and reflex. Pick so SB woofers and try them. Check the step response in both formats. You will see longer settling time for reflex.

 

RE: Magico M2, posted on January 27, 2020 at 08:16:56
cawson@onetel.com
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 I see little to be gained by speaker frequency response measurements. If you take the measurements in an anechoic chamber or the middle of a wheat field, you will record the response of the speaker unaffected by its environment. But of course we don't listen to our music in anechoic chambers or wheat fields. We are surrounded by walls and windows that reflect some frequencies, maybe straight back to the speaker or our ears, or curtains and carpets that absorb other frequencies.

Measuring by instruments in any room other than our own listening room is pretty meaningless to us - the potential buyer. Whether magazines should simply stop taking speaker frequency response tests completely and rely on their reviewers' expert ears to subjectively review speakers, I'm not sure. I think I'd probably favour no such tests for speakers (OK to measure sensitivity, etc), and leave us to interpret subjective reviews as we see fit.

My own case in point relates to Robert Deutsch's review of the Avantgarde Uno in September 2000 Stereophile and the subsequent choice of this speaker as your Joint Speaker of the Year. His excellent review (all 10 pages of it) described exactly the sort of sound I was looking for after having recently bought ATC 50 Actives that I just wanted to push 20 feet further away from my listening chair. As a direct result of his review (and I'm sorry to say, ignoring your 5 pages of technical tests), I bought a pair. They lived 100% up to my expectations and I kept them until last year - to be replaced by slightly more recent Avantgarde Duos. Would I have been put off by the Unos' relatively poor test results? I hope not. Would the ATCs have measured better than the Unos? Yes, by a mile I suspect, but I'm sure that had I bought my ATCs on the strength of measurements, I'd have been sorely disappointed. As it happened I bought the ATCs unheard and without reading any significant reviews, so I can't blame anyone but myself! The ATCs are fantastic speakers, but probably best left in recording studios. As music lovers, we should be looking for speakers that fill us with joy and excitement when listening - it matters not a jot what the oscilloscope thinks of them!

Peter

 

Interpreting Measurements..., posted on January 27, 2020 at 09:10:23
Doug Schneider
Reviewer

Posts: 881
Location: North America
Joined: April 16, 2005
 Hello,

I'm just about to measure a Magico in a real anechoic chamber and saw your post. In particular, this: "Measuring by instruments in any room other than our own listening room is pretty meaningless to us - the potential buyer."

Not so much. If you take really good anechoic measurements, on and off axis, you can not only glean quite a bit of information from them if you know how to interpret them, you can almost always "see" the anechoic measurement within an in-room measurement. From that, you can tell what the speaker is doing itself and what impact the room is having. It's not by any means meaningless at all.

Doug Schneider
SoundStage!
www.SoundStage.com

 

RE: Interpreting Measurements..., posted on January 27, 2020 at 20:33:29
hahax@verizon.net
Audiophile

Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 Some of Floyd Toole's work on measurements backed up by double blind tests would seem to support your view.

 

RE: Interpreting Measurements..., posted on January 28, 2020 at 08:13:11
Doug Schneider
Reviewer

Posts: 881
Location: North America
Joined: April 16, 2005
 Hello,

It doesn't "seem to" -- it definitely does support it! And believe me, that research works. Have you heard a Revel, for example? And many speaker makers when you talk to them in depth know the research is spot-on.

Doug Schneider

 

Speaker Measurements, posted on January 28, 2020 at 09:03:18
Inmate51
 "I see little to be gained by speaker frequency response measurements."

"Measuring by instruments in any room other than our own listening room is pretty meaningless to us"

*****

Wrong.

 

RE: Magico M2, posted on January 28, 2020 at 10:09:57
John Atkinson
Reviewer

Posts: 4045
Location: New York
Joined: November 24, 2003
 >Measuring by instruments in any room other than our own listening room is
>pretty meaningless to us - the potential buyer. Whether magazines should
>simply stop taking speaker frequency response tests completely and rely on
>their reviewers' expert ears to subjectively review speakers...

This is not correct. Watch the linked video where I discuss the usefulness
of measurements accompanying reviews.

John Atkinson
Technical Editor, Stereophile

 

RE: Interpreting Measurements..., posted on January 28, 2020 at 20:35:11
hahax@verizon.net
Audiophile

Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 I haven't heard a Revel lately but I have friend, Murray Zeligman, a very creative speaker designer who knew Kevin Voecks well years ago. And he told me Kevin was one of the good guys who knew what he was doing, that he could make a speaker do almost anything he wanted. And I do know how well Revels measure(I am a strong advocate of measurements, that careful use of them adds and clarifies or knowledge). I also know that Revel made use of Floyd Toole's work.

My small understanding of Toole's work always looked to me that if a speaker did what he thought was good measurement wise it would be accurate. I've often wondered though if there are measurements that don't do what Toole advocated that also were good reproducers too.

 

Oh God, posted on January 31, 2020 at 16:30:38
Bill the K
Audiophile

Posts: 8384
Joined: June 3, 2006
 Even JA One is being replaced by AI. What next!

Bill

 

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