Acoustic systems anatomy: the wonders of combinatorics or a lot of personal information about the NEAT Acoustics IOTA Alpha spike dwarf

Some technical solutions, due to their uniqueness, it makes sense to consider on specific examples. There are many common design approaches for acoustic design of floor acoustics, but in this case we will talk about a far from typical device. The product described interested me with a number of characteristic differences. First of all, the design of the case, no less interesting was the comparison of the subjective perception of sound with the technical characteristics and measurement data.

Enthusiastic feedback from our category experts and the marketing “background” in the audio press have long been no convincing arguments for me. With the first, I often differ in the subjective assessment of components, and the degree of delight of reviews in audio media often depends on the fullness of poured glass on the volume of the manufacturer’s advertising budget. Therefore, I was very surprised when I put the AU strong five with a minus (on a five-point system), and placed it on one of the first places in the personal rating.

Let me be subjective in this review (this rarely happens to me) and say that this system impressed me a lot. In short, I am not a big fan of singing denim praises and I know that any device has its drawbacks, and any technical solution in acoustics is a difficult compromise. In this case, I want to say a lot of good and a little bad. When I first saw the NEAT Acoustics Iota Alpha , I had the idea that it’s rather a matter of design sophistication, and that reducing the size of the speakers is unlikely to have a positive effect on the sound.

The presence of long spikes also alerted. The spikes could indicate that the manufacturer relies on the attractiveness of the system for audiophiles who believe in the effectiveness of "anti-vibration" solutions of such a plan. As it turned out later, everything is much more interesting, both with sound and with spikes (the rare case when a relatively small volume of the body surprises with a good sound, but there are very specific practical benefits from the spikes, not connected with the myth of resonance damping).

Acoustic design

Acoustic design is perhaps one of the most interesting features of the Iota ALPHA . Engineers combined indoor and bass reflex design types. So the upper part of the system, where the midrange speaker and ribbon twitter is located, is a closed box. The speakers of this section are fixed on a panel inclined at an angle of 30 degrees, which is done to form the required radiation pattern (taking into account the dimensional features of the device).

In the second section there is a phase inverter and a 134 mm woofer directed downwards to expand the vertical diagram and form a three-dimensional scene. The spikes I mentioned above were not used as some kind of “magic” vibration isolator, but for a completely practical purpose - to provide the necessary distance from the speaker floor (with the woofer fixed on it) to the floor (the surface, on which they are installed). The distance from the floor surface to the woofer diffuser is 1.7 inches, which, according to the developers, is optimal for correct reproduction of the low-frequency range.

The phase inverter hole is located on the rear panel, which does not allow placing the speaker close to the wall. A sufficient distance between the rear panel and the wall will be 30 - 50 cm ... In addition, the manufacturer recommends covering the surface on which the system is installed with sound-dispersing material (for example, put a felt mat under each speaker) and the wall behind the speaker.

Surprising overall dimensions, Iota Alpha turned out really small for floor acoustics. NEAT engineers decided to move away from the seemingly unshakable principle that the bigger the boxes, the better the sound. Thus, using combined solutions, they got more than a decent result with dimensions (H, W, D): 450 (with spikes), 200, 160 mm. With such modest dimensions and not too outstanding sensitivity of 86 dB, I was surprised that the system can easily voice 25-30 square meters. m. area (the amplifier was used with RMS 30 W, 4 Ohms).

The result of using the selected combined design, it became a very interesting sound. Acoustics are characterized by accentuated low and midbass, energetic middle and expressive exact high. A distinctive feature of acoustics with such atypical dimensions and acoustic design is the wide horizontal and vertical radiation patterns, as well as the exact realistic arrangement of seeming sound sources in the scene. As our experts emphasized: “I rarely had to meet such decent acoustics with such dimensions.”

AFC, distortion, as well as other measurable and subjective parameters

Before I talk about the Iota Alpha frequency response graph and other system characteristics, I want to emphasize that when choosing speakers for myself, I usually focus mainly on measurable technical indicators. At the same time, if I had to choose a system for the house by ear, I would most likely spend $ 2000 on the described acoustics.

The frequency range from 33Hz to 22kHz, which is able to reproduce Iota Alpha is sufficient and even somewhat redundant (taking into account the physiological limits of perception). The declared passport range corresponds to reality, which is determined by hearing (I can’t hear above 17 kHz, but my seven-year-old son recognized the test signal of 21 kHz) and in the case of hardware measurement. Deep bottoms also do not cause doubts in the stated range.

Frequency response

The frequency response graph is what puzzled me. I am a person accustomed to monitor sound, which I later adjust to the individual characteristics of my hearing with an equalizer (taking into account the acoustics of the room, genre nuances, mood) - if roughly, then I change the equal frequency response to the one at which the music will be most pleasant to my ears. In the case of the Iota Alpha, the frequency response graph is surprisingly uneven, but everything sounds good. This schedule has guarded me not less, than use of thorns.

AFC test from John Atkinson, "Stereophile"

Meanwhile, the subjective perception of sound quality remained high and, moreover, the sound almost did not require equalization. From this I concluded that for my frequency response (I emphasize this moment) of the ears, this sound is very good and does not require additional torment with an equalizer. On the other hand, I would not recommend this acoustics as a studio (as well as for recording / mixing / mastering at home), since the sound, as can be seen from the frequency response graph, is very far from the monitor standard.


With a subjective assessment (listening to Rammstein covers performed by a children's choir and a concert for Mozart's D-dur flute and orchestra), blurring (typical of a high level of intermodulation distortion) cannot be noted. The harmonic coloring of the sound is also not heard. These estimates coincide with the passport data acoustics, THD does not exceed 0.5%. The manufacturer does not write about the intermodulation component, but in vain. In the case of hardware testing of the Iota Alpha pair by the standard two-frequency method, the IMD indicator did not exceed 1 - 1.15%.

I suppose that the low level of distortion is achieved largely due to the design of the filter system. Unfortunately, we could not find detailed information about the crossover circuit, but it is known that the design used beloved audio files, precious metal capacitors from Mundorf and ICW Clarity, as well as Volt coils, which many consider to be very true. Bourgeois publications also write about the use of chokes with an air core and low DC resistance.

Features of resistance.
At the overwhelming majority of frequencies (but not lower than 50 Hz) the resistance of the AU reaches 6 Ohms real (at the declared 4th). According to the expert John Atkinson (who wrote about this system in Stereophile), this means that the speaker can work correctly with an 8-ohm amplifier.

It should be noted that at a frequency below 50 Hz, the resistance drops to 4 Ohms, and at a frequency of 10 Hz (outside the audible range) drops to 3.6. From this we can conclude that the eight-amp amplifier working with this speaker will have certain difficulties with the bass.


Summing up the dry residue without personal predilections, it can be said that IOTA Alpha is a speaker system with an original design, a low level of nonlinear distortion, a volume that is sufficient for an area of ​​30-50 square meters, a wide horizontal and vertical pattern, and relatively small dimensions. , accurate and voluminous scene, as well as controversial, in terms of fidelity playback, the frequency response graph.

My subjective assessment is much higher. Hearing this system, I realized that there are technical solutions that provide decent sound quality without the use of huge boxes. I have already written about sound, in short, the frequency balance, the so-called. the detail, the location of KIZ and the “volume” of the scene deserve the highest praise. I don’t really like abstract definitions, but in this case let me characterize the sound as “realistic” or “alive”.


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