Infinity Primus P363 Loudspeaker

How well a speaker has to work to be satisfying is not an open-ended question. Eventually, speakers will get to be as good as there is any use in their being and when that happens, technological progress being what it is, it will not be long before they are as good as they can be at low prices.

People ought to rejoice in this, not resist it. Music is for everyone. But however one feels about the idea, in the face of speakers that cost tens or even hundreds of thousands of dollars a pair, the whole point might seem very remote at present.

“And then along came Jones”—or in this case, the Infinity Primus P363—and suddenly the idea seems a lot less remote than before. There have been other inexpensive speakers that were startlingly good. Several times in the history of TAS one writer or another has declared some inexpensive speaker to be good enough or even all but perfect (I recall an early NEAR speaker for example, and Harry Pearson’s reaction to the Sound Dynamics 300ti). Nor am I going to suggest that the Infinities as I shall call them hereafter are perfect. They are built to a price point and there are things one could do a little better by spending more on construction. Indeed, there is a sort of cottage hobbyist industry flourishing of people modifying these speakers for themselves or others.

What I am suggesting is that these speakers are both remarkably good and remarkable in the rationality of their design. Infinity has apparently isolated the things that really count about sound and gone after these things while cutting corners—corner-cutting being necessary at the price—in ways that do not matter all that much. The results are startling indeed.

These speakers are very inexpensive. They are four-driver, three-way floorstanders. And they are currently being offered for sale quite frequently for under $300 a pair. (Their MSRP is higher but they are being heavily discounted.)

I am well aware that if I just start talking about the sound—although Neil Gader described a somewhat earlier version of the speakers as “amazing” in his capsule review in a survey in issue 149—people are likely to think that this is just REG being an iconoclast or an agent provocateur, doing for speakers what he tried to do for phono cartridges years ago with his review of the Audio Technica ATML170.

The Technical Story
So I want first to tell you about the technical behavior of the speakers. Lots of you probably think that speaker sound is not well characterized by measurements, but bear with me and perhaps we can clarify this point a bit along the way.

Let’s start with distortion. For all practical purposes, the Infinities do not have any. The distortion is on the order of 55dB down from the signal from 100Hz on up at 90dB (this 55dB down corresponds to around 0.3% or less). The Canadian NRC’s famous speaker-measurement program does not even bother to show in its distortion measurements distortion levels that are more than 45dB down. They clearly think below that level, distortion is inconsequential. On this basis, the Infinities are essentially perfectly “clean,” truly distortion-free. The Eminent Technologies and most electrostatics are even a little lower—maybe 60dB or more down from signal or in the case of the ETs even better at many frequencies. But the Infinities are running about as well as a box dynamic speaker is likely to run in this regard and better than most. And they sound it. The Infinities are really clean and pure-sounding. You want clean midrange; they give you clean midrange.

Next act: The Infinities are really flat in response. Now here one has to be a little cautious. They are not absolutely as smooth in the midband as some speakers that run a single driver from the bass on up to say 3kHz. The Harbeth P3ESR is smoother from say 300Hz to 1kHz, for example. But not by much! The Infinities have a very smooth, neutral midrange, and the very small measured variations around 600–800Hz are just that, very small.

Now what is true is that, to my ears, the whole region above around 1kHz could be pulled down by about 2dB to good advantage. As is, the speaker sounds a little midrange-recessed relative to the upper mids and lower treble, above which response is very smooth and flat but slightly up in level. Many audiophile speakers are, in fact, midrange-forward, so this small recession effect may strike you more than it really should. In any case, such a small reduction of the treble is a trivial thing to do electronically. (Buy an NAD and the controls will be right in front of you.)

Now we get to where the Infinities just go romper-stomper over practically all the competition. Namely: The off-axis behavior of the Infinities is just all but perfect in evenness and lack of coloration. The Infinities follow the pattern of rolling the off-axis down starting at a fairly low frequency (as opposed to say the JBL LSR 6332, which also has very smooth off-axis behavior but keeps directivity constant up to around 1kHz and shoves the baffle-step down quite low, by using a wide front cabinet). This is a choice, but it is an essentially perfectly executed choice in the Infinities. And if you stay down where you belong in listening position, (i.e., below the tweeter’s axis), the vertical consistency of the speaker is also superb. (As this listening position is low, it might make sense to lift the speakers up, on cinder blocks say.)

The effect of this is that the Infinities are superbly uncolored and un-speaker like. And they vanish as sources in a way few others can match, presenting a seamless and stable sonic image. This is no-compromise behavior. Not good for the money, not good for two or three times the price, but just plain good, period. You can spend $90,000 for a pair of speakers and not do as well in radiation pattern. In fact, most likely if you spend that kind of money that is exactly what you will do—not as well—because, in fact, very few speakers do do as well.

What Technical Information Means About Sound
So let’s pause for a moment and ask ourselves, just exactly what can be wrong with a speaker that has ultra-low distortion, very smooth and flat frequency response, and extraordinarily smooth off-axis behavior, and which incidentally will play really loudly with rather little power needed. The answer of course is, not much. A speaker like this is bound to sound really good and indeed it does. Floyd Toole has retired from Harman (of which Infinity is a division). But his influence lives on and if he was a bit doctrinaire about flat response, off-axis consistency, wide bandwidth, and low distortion being all that mattered about speakers, that does not mean that these things do not count for a very great deal. And the Infinities are the proof of the pudding.

All right, so there are a few problems. First of all, this is a speaker that I take it is aimed at the home-theater market, and the balance is bass-oriented, or more precisely there is a certain lack of control, even boom, around 100Hz. Presumably people have figured out that every speaker is going to need some fixing up in the bass most likely, and, hey, should have found out that when the frequency response is corrected, the timing (phase behavior) will also be corrected. So this whole bit with the boom in the bass is a sort of non-event. (I know some people are a bit troubled by the idea that fixing frequency response fixes phase response, but it is just mathematics. You can believe in it without worrying about how it works.)

The Infinities have metal drivers (aluminum anodized on both sides to create a coating that supposedly damps breakup modes). Any potentially troublesome out-of-band breakup of metal drivers is well-suppressed here by the steep-slope crossovers. I think the effect of this suppressed breakup behavior is not really going to be audible on music material. I suppose in an ideal world the break-up frequencies would be even further out-of-band. Some manufacturers go to heroic and expensive measures to shove the breakup modes way, way out of band. That is better in theory—but at a certain point it may be only in theory. Phenomena do have thresholds, and it is worthwhile listening to see what one really needs in such situations.

The Actual Sound
So how good do these speakers sound? With bass adjusted, treble shelved down slightly, speakers positioned so the listener is on the best axis—and incidentally with the listener at least 8 feet from the speakers (which do not integrate correctly very close up), they sound remarkably good, with a neutral character, a remarkable vanishing act as an apparent source, a lot of detail without exaggerated treble (high percussion is really excellent), and enough dynamic capability to deal with large-scale music. My usual orchestral favorites tests pieces—Rachmaninoff Symphonic Dances on ProArte, Dallas Symphony, Mata, for example—sound well-resolved, smooth, natural both in tonal character and stereo presentation, and completely convincing dynamically. The extreme bottom is missing but at the price there will plenty of money left for a subwoofer if you must have pipe organs and earthquakes.

In a dark room, not knowing what was being played, I think few people would be willing to say definitely that they were not listening to a high-priced assault on the higher realms of speakerdom. This probably sounds heretical, for a pair of speakers that costs less than many people spend on a power cord or two. But there you have it. The times, they are a-changin’.

This does not mean that the Infinities are the ideal speaker for any particular listener, though I find it hard to believe that, with the treble tamed, anyone would not like them. For one thing, the choices of radiation pattern that speaker designs make influence how they sound, and any one choice may not be for you in particular. And drivers of other materials have a subtly different character which might lead to a preference elsewhere. But those things are true for speakers that cost a bundle, too.

At the very least, this is a speaker that everyone ought to listen to carefully. At the price, one could almost buy them just to try them out, or a club or group of friends could buy them for the price of a movie ticket for each member. I do not want to appear to be deliberately provocative, but these things are really something. In many fundamental ways they are in the top echelon of anything out there. Hard to believe, perhaps, but have a listen. They do more than sound like a really good speaker. They sound to me like the beginning of a new era in audio.

SPECS & PRICING

Type: Floor-standing three-way loudspeaker
Driver complement: Two 6″ anodized aluminum (Metal Matrix Diaphragm) woofers, one 4″ MMD midrange driver, one wave-guided MMD tweeter
Crossover frequencies: 350Hz, 3kHz, 24dB/octave slopes
Sensitivity: 93dB
Frequency response: 38Hz–20kHz
Maximum suggested amplifier power: 200 watts
Nominal impedance: 8 ohms
Dimensions: 8″ x 39″ x 13″
Weight: 48.5 lbs.
Price: $398 per pair (frequently discounted)

HARMAN INTERNATIONAL
(800) 553-3332
infinityspeakers.com