Speaker Asylum: REVIEW: Infinity Systems Monitor-II Speakers by serus

Model:	Monitor-II
Category:	Speakers
Suggested Retail Price:	$950 (ca. 1980, est.)
Description:	Large 4-way floor-standing speakers
Manufacturer URL:	Infinity Systems
Manufacturer URL:	Infinity Systems

Review by serus ( M ) on March 01, 2005 at 19:48:07
IP Address: 66.81.76.34

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for the Monitor-II

A few months ago I stumbled across a pair of Infinity Monitor-II speakers at a local Goodwill store. They were part of a home theater setup with almost-as-big pair of Infinity WTLC. Heck, I grabbed them both...
The TL in WTLC stands for "Transmission Line", and the Monitor-II shares that design features as well.
When you hear "Transmission Line", what comes to mind is a peaky frequency response, perhaps with colorations from phase anomalies across the bass and upper bass frequency range. That's the theory, which might be true for the "pure" 2-way TL designs, but is far from it for the 4-way Monitor-II's. Four-way?! Oh, my God!
Yepp, first you look at the monsters and you want to cry. I mean, no way I can get smooth driver integration in a small room like mine... The room is only 17' x 14', but it's open into a similar room. But it's a small space and the listening position is only 10' away from either speaker.
I added some room treatment to avoid treble reflection from the speaker on the right, which is very close to the corner. The speaker box is stuffed so dense with acoustic material, that the rear port does not seem to mind the proximity to the walls on that side.
The speaker on the left stands in the large opening to the other room. I had to play with placement to get them to work well together. This was quite easy. I've seen speakers which are really picky about fractions of an inch. The Monitor-II's like precise placement, but are quite forgiving. Bottom line, they are not hard to set up in your room.
Each box weighs about 70 lbs. While that's not much compared to some "coffins", new and old, it is advisable to have a second pair of hands on site...
I first drove them with an amp that's rated around 40 WPC into their nominal 6 ohm impedance. In that little space, the amp was hardly getting warm. These large speakers are quite efficient, and not only on paper!
Recently I switched to a 3 WPC amp. Do I hear some rumbling?
Only in certain rock tracks you could tell that some more power might help. These speakers are efficient!
I won't match them with a 2A3 amp, but they sure don't need a kilowatt behemoth...
And that is a good thing. Big amps have great dynamics, but when it comes to refinement and musicality, I prefer minimalistic amps - tubes or solid-state.
Sound
Surprise, surprise!
Big speakers always give the impression of a disco speaker. You know, large room, lots of noise, 120 dB SPL... Intimate sound belongs with small ones, right?
Wrong!
These big boxes are very refined. You can play them at low levels at midnight and the next day haul them out to the front yard to retaliate the boom boom sounds emanating from your next door teenage Camaro. If this happens to you, please control yourself and be civilized. I suggest you play some Tosca...
There is a difference between low level and loud music, but in both cases, the speakers are well controlled and refined at the same time.
Let's talk loud first. The thing that gets your attention is the big bass. I don't mean a boom box bass, but a well controlled, refined, clean bass that "rolls" into the room. Yes, it crashes into your chest, it shakes walls and furniture, but that's no biggie. Many speakers can do that. What not many of them can do is play below 30 Hz with the same finesse as at 50 Hz. That's what separates the men from the boys!
My friend Herb came over to hear the wonder speakers. Herb has Sonus Faber Amati Homage, which are no slouches in the bass region and to say that they don't lack much in refinement is a gross understatement. But the Amati don't have the bass finesse of the Monitor-II's. A big plus any way you look at it.
What about shaking walls late at night? We sure don't want the spouse out in the living room with her massive rolling pin, with no intentions of baking a cake...
Well, I did say there is a slight difference between low level and loud playing with these speakers. This can't be a fluke. Must have been a designer's insight, as he was hypothesizing bodily injury liability scenarios...
The woofers in particular don't play loud at low input power. These big motors need some oomph to move and that causes a slight decrease in bass output in very low level listening. The bass is there, just at a lower level than "flat" response. That's not a good thing for average listening, but it's a great plus for those tense moments around midnight...
To sum it up, you can play pipe organs and Odyssey 2001 or the 1812 overture to the fullest experience, but you don't have to switch to your mini monitors - or headphones - when a little peace and quiet is desirable. These giants can tippy-toe...
Let's examine the other extreme. Those funny looking Walsh tweeters are the biggest visual impact with those speakers (and the WTLC too). They were the main reason why I bought these in the first place!
I learned a little about the theory behind them. Omnidirectional pattern from a super tweeter doesn't sound like the right thing to do, but you don't argue with success. These super-tweeters have the speed and character of a ribbon, and we are talking refined cymbals and top hat, without the excess glare of metal domes.
You don't hear much of those upper harmonics in your average music track, but you learn very quickly to appreciate the very extended and oipen sound in the treble region. Relaxed, in a sense, but very extended.
There is no edginess to these Walsh tweeters. I'm a believer!
I was first worried about the 360 degrees pattern. How can they image correctly with that?
Not a problem!
This pattern seems to create a bigger "decent" listening zone. The "sweet spot" covers maybe half the room...
In between the 12" woofer and the Walsh tweeter are a mid driver and a dome tweeter. They seem to cover the mids and lower treble extremely well, integrating very smoothly at my far listening position. Depending on the electronics and other components, these speakers can produce outstanding sound!
In my case, I played a large variety of my favorite material. These speakers did justice to male and female voices, violin and piano, dobro or electric guitar, harmonica and drums. Never did I feel that they favor classical over Jazz or vocal over instrumental. I could switch at will to any material on hand and always receive the VIP seat and the appropriate music hall - or the smokey night club...
With the right system and material, these speakers just disappear out of your way. You get the nuances of echoes in the recording venue, the sense of depth due to correctly-aligned harmonics as well as the beyond-the-walls soundstage. It's all there, just as I expect to hear it from a refined modern speaker!
They have some little weaknesses. You may find that the mid driver distorts at (deafening) high levels, and they may not be the "universal" speaker that you can run with your low power tube amp. These are real nit-picks!
These speakers will do justice to any music and any amp. If you find a set, you should grab it. The woofers may need refoaming. Do it! Or pay a pro to do it for you - they are worth it!!!
How much did I pay?
My friend Herb asked the same question and being an honest person that I am, I had to tell him the truth... Herb immediately suggested that I'll go for a confession... Vintage is like that. Some of them are a real steal!!!

Product Weakness: Nothing more than nit-picks...
Product Strengths: Refined, clean deep bass, ribbon-like treble, extremely balanced

Associated Equipment for this Review:
Amplifier:	solid-state prototypes
Preamplifier (or None if Integrated):	tube prototype
Sources (CDP/Turntable):	Sugden BD2/A with XLM-II cartridge, Revox B-225 CDP
Speakers:	review samples
Cables/Interconnects:	my own X-2 prototypes
Music Used (Genre/Selections):	wide range
Room Size (LxWxH):	17+ x 14 x 8
Room Comments/Treatments:	reflections supressors on two walls
Time Period/Length of Audition:	3 months
Other (Power Conditioner etc.):	misc. line filters
Type of Audition/Review:	Product Owner

Product Weakness:	Nothing more than nit-picks...
Product Strengths:	Refined, clean deep bass, ribbon-like treble, extremely balanced