Review: Unity Audio Inner Soul Towers

The Unity Audio Inner Soul Towers

Review by Colin Mckay

The speaker being reviewed today is not about the latest exotic offering that only a small sector of the audiophile community would be interested in. Indeed, we often see speakers with small full range drivers categorized into market niches like “need a speaker that your flea-powered single ended amplifier can drive? Look no further!” Now, these Inner Soul Towers do fit that category perfectly. But, if this review was pigeonholed like that, I would be doing a great disservice to Omer Humayun, founder and owner of Unity Audio.

In fact, what Omer has done here is to offer us the most direct and cost-effective way to gain access to we are all aspire to have. That is, to experience a genuine musical moment in the confines of our humble abodes. Not just once and awhile, but every time the whim takes us to sit down and relax while listening to our favorite piece of music, or to watch a film. This is the essence of these speakers, and I refuse to see them as being otherwise.

In fact, the smaller full-range driver is the most common driver that you will find on the consumer market today. For example, just look at your radio, the Bluetooth speaker for your smartphone, your car stereo, or, in fact, any small audio device. What will you find? A small full range driver! Why? It is because, penny for penny, these are the best sounding drivers you can buy. Omer has simply captured this truth and has raised the standard of these drivers to new musical levels. Bravo Omer!

Unity Audio is a Canadian company that has been around since 2005. This Ottawa-based company has established a solid reputation by designing and manufacturing audio cables (some of which Noam reviewed here) and a series of efficient speakers which utilize full-range drivers. Both his audio cables and speakers have met with modest success, including several reviews that have highly praised his products. For example, our friend Dave at gave an A+ to Omer’s most popular speaker, the Unity Audio Inner Soul Monitors, which Tim also reviewed very favourably here on Wall of Sound. Unity Audio sells its products directly through their website, as well a a few select retail dealers.

This is a review of Omer’s newest incarnation, the Unity Audio Inner Soul Towers. Like the monitors, the towers are hand assembled and finished in Canada. As well, the design, build quality, and finish of the Towers represent a price/performance ratio that makes these speakers a very attractive choice for those seeking to get the most for their hard-earned dollars.

The drivers utilized in the towers are the same as the ones used in the Unity monitors. They are 12 cm full rangers manufactured by Airborne and distributed in Canada by Solen Electronics. Unity Audio has modified them to their own specifications. I am sure the modification is a well-kept secret. These drivers have a cast frame which is better than your average stamped frame. Their surround is made from rubber, rather than resinated cloth. The cone is made from wood that most consider is bamboo. Airborne states that they are simply made of wood. The center cap is an attractive gold colored phase plug made of aluminum; a wise choice of materials as it is very light. Finally, and perhaps most importantly, the speaker damper is made of Conex which is a special resin-impregnated polycotton based fabric. For your information, the damper guides the speaker cone and voice coil as it moves back and forth during use. Conex is a material that provides increased rigidity, longer travel and improved moisture resistance over the more common materials used in other damper guides.

Altogether this makes for a high-quality speaker which may weigh in a little heavier than its paper cone cousins such as the Fostex line of full rangers. The tradeoff is that the Fostex do have higher efficiency ratings. However, I would give the Airbornes the nod over the Fostex in the durability department.

The Airborne full-rangers have received some criticism for being a little harsh in the upper middle frequencies when measured on the test bench, or pushed to their extreme limits. I experienced this harshness as well when with my first listening sessions. The speakers had perhaps 40 hours of use on them. So as not to jump to premature conclusions, I requested an extended listening and break in period for the speakers. After 100 hours of break in time, the mid-range began to smooth out. After approximately 200 hours, this harshness disappeared under normal listening conditions. I suspect the chief culprit in this case are the speaker dampers. The Conex material does need an extended period to loosen up and finally settle down into their working parameters. If you are patient in breaking in these speakers, you will be fully rewarded as they are a superb sounding driver.

The driver is of course run without a traditional crossover, and is housed in a minimalist, no-frills-but-high-quality package. Time and care has been taken to sheath the high density MDF cabinets in an attractive cherry or maple veneer with, satin lacquer. All internal wiring is from Unity’s own Solid Link series. The speaker taps accept either banana plugs or spades. My only wish is that the connectors were spaced a little farther apart; I did encounter a slight lack of space using my heaviest gauge cables with wider spades. There are no isolating feet or grill covers. I never felt the need for either of them. In fact, I found the speakers benefited from a direct coupling to my birch and hickory hardwood floors. You should try and find out what works best for you. Here are the speaker’s specifications from Unity Audio’s web site.

Type: rear ported, single driver, floor standing tower
Cabinet: Canadian MDF construction
Finish: cherry (pictured) or maple veneer with satin lacquer
Driver: Unity 4-inch wood fiber full range
Internal wiring: Unity Solid Link series
Frequency response: 40Hz – 20kHz +/- 3dB, placement and room dependent
Recommended power: LESS IS MORE
Sensitivity: 91 dB
Impedance: 8 Ohm
Dimensions: 6.5W X 6.5D X 34.5H (inches)
Weight: 36 pounds/pair
Warranty: 10 years, limited


Now, I don’t want to repeat everything that’s already been written about the Towers’ smaller sibling – the stand-mount Inner Soul loudspeakers. Again, you can refer to the numerous reviews of that loudspeaker at Unity Audio’s website. The Inner Soul Tower does have all the qualities of the stand-mount version. The mid-range is transparent, the attacks and the decays are quick, and above all, the tonality is as realistic as you could beg for. The highs do begin to roll off earlier than most speakers with high quality tweeters. I noticed this the most when comparing them with the KEF HTS6001…. The KEF’s are high definition co-axials, and one of my favorite surround sound speakers. Yes, the KEF’s highs were more pronounced, or more distinguished; however, the KEF’s also pushed the treble much more forward. The Unity Inner Soul Towers presented a more expansive, deeper and wider top-end. In doing so, the Unitys presented me with a more satisfying perspective. On the lower end of the musical scale, the Towers provide very convincing bass notes in the upper bass octaves. Using test tones, I noted that in the very lower regions, the bass began to roll off very rapidly at around 40-50 Hz. As Omer has stated, your bass preferences can be adjusted by room placement. In my largest listening room, which measures 30 by 20 feet with a 9-foot ceiling, I was able to squeeze the most out of the lower octaves by placing them nearer to the corners of the room. Most likely, I was taking advantage of the rear ports of the speaker.

I’m sure most of you are asking the question; how do the Inner Soul Towers differ from the stand-mounted speakers’ sound? In my opinion the biggest improvement between the speakers is in terms of musical scale. Imagine the keys on a piano keyboard. When you hit the Middle C key, you would not perceive much difference between the two speakers. When you begin to strike other keys while descending in the octaves, the difference in the two speakers would become more and more apparent. The towers produce a tonally more accurate timbre and pitch the farther you descend into the lower octaves. What this translates into is a much more accurate scale of musical reproduction. If it is there in the recording, the stage is wider and deeper. The instruments are more separated and distinguishable due an improved reproduction of each of their sonic characters. This is true as well for the higher octaves. It’s as if we have stepped up a few levels in the resolving power compared to the stand-mounted versions. And yes, these differences are very remarkable. I highly recommend the Towers, even at a few hundred dollars extra over the stand mounts.

On a finishing note a would like to describe the synergy I encountered using the Towers with various amplifiers. These speakers are exceedingly transparent and deserve to be matched with the highest quality equipment that you can afford. It does not have to be exclusively matched to tube amplifiers. I used the towers with several transistor based circuits ranging from Class A to Class D.  What the speakers did – within their limits – was to transmit the various qualities that each of the amplifiers possessed. They added very little to the overall signal path. These speakers do not need much power. Just as importantly, they do tolerate higher wattages. I don’t recommend turning your 150 watts per channel amplifier to it maximum limit, and leaving it there to listen to some tunes on the Towers while you take a bath. What the Tower does do at more reasonable listening levels, is handle all the musical peaks you can throw at it without audibly distorting the signal.

Just for fun, I integrated the Towers into my cinema surround system. Even though they replaced a much more expensive pair of speakers, they presented a more articulate approach to the scenes we watched, above all in the dialogues. They also blended perfectly with my electrostatic center channel, which cost me $700 more than the price of the Inner Soul Towers. I ended up crossing them over with my three subwoofers at 50 hertz, and voila, cinema surround heaven! One evening, while watching a film, I asked my wife which speakers she preferred in the set-up. I was not surprised when she responded that she liked the Unity Towers more.

So here we have it. This is a pair of floor standing 4-inch full range stereo speakers with outstanding transparency, musicality and efficiency. In their price range, if these are the qualities that you are looking for, then look no further.

You must be patient with them. They do need much more time than your average speaker to fully break in. They are sensitive to where you place them, especially in the lower regions. The trebles may be slightly more rolled off than you may be used to. However, this does not diminish their performance in that region. What more can I say about the Inner Soul Towers – I highly recommend them. Congratulations, Omer, you do have a winner on your hands.


Unity Audio Inner Soul Towers  $1350 CDN./pair

Manufacturer’s website:

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5 Comments on Review: Unity Audio Inner Soul Towers

  1. Balsac Turdburgler III // 2017/11/25 at 8:42 am // Reply

    Nice review!

  2. With countless examples of operational Fostex drivers on the second hand market being 40-50 years old……

    your quote

    ” However, I would give the Airbornes the nod over the Fostex in the durability department. ”

    Is pure nonsense….. have you used the Airborne’s for 40-50 years ?

    Questioning the validity of anything else you may want to say

  3. Bogdan- there have been a lot of Fostex drivers clearly made to a price point, and I think Colin was saying the build quality of the Airbornes is robust. I don’t think he meant to imply anything about longevity.

    • Colin McKay // 2017/12/02 at 11:11 am // Reply

      Durability…. The question is durability, not longevity. Your point about validity stops there. I would love to try these speakers with the Fostex FE108EZ 4″. They run about $175 CAN apiece, that is $200 more than the the Airbornes. They look extremely well made. How about it Omer? Nod, nod, wink, wink!

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