Epik Sentinel Subwoofer Review

Build Quality and Setup

Epik Subwoofers is a relatively small, Internet-direct company that sells one type of product: subwoofers. Epik subwoofers are frequently recommended, praised and lauded on message boards and forums for their ability to deliver deep bass with great impact at comparatively low prices. The subject of this review is the Epik Sentinel: physically the smallest ported subwoofer offered by Epik. The description found on Epik’s website promises "the most 20Hz output in the smallest possible cabinet." Epik also promises "musicality and sound quality that is found in similar subwoofers costing much more than the Sentinel." My experience is that the first promise holds true, but the second promise does not.

Build Quality

The Sentinel subwoofer arrived in a single box marked "Fragile" and "This End Up". Inside the shipping box, four 2-inch thick, molded foam inserts almost completely encased the subwoofer and its grill. The packaging should prevent any damage during shipping. However, the grill is laid on top of the subwoofer during shipping, so it is vital that the box not be placed upside down.

The Epik Sentinel measures 14.5” wide x 20” tall x 20” deep and weighs almost 90 lbs. It is a slot-ported subwoofer with its 1-1/4" high x 13" wide slot-port located on the bottom front. The cabinet is made in-house by Epik using a CNC router to shape the 3/4" MDF material. The front baffle is dual-thickness at 1.5". Internal bracing is used along with a prodigious amount of Dacron filling. The cabinet is finished in a black, textured paint. There are no feet or spikes what-so-ever and no threaded inserts or other means of attaching feet or spikes. The entire cabinet appears seamless. Only a barely visible seam within the port gives any indication that the cabinet is not simply a single, large block of MDF. All of the corners and edges are rounded.

The Sentinel uses a 12” diameter aluminum driver powered by a 600 Watt amplifier. Both the driver and the amplifier are exclusive designs built specifically for Epik. The driver is flush-mounted to the front baffle, but I found the fit and finish to be a little bit lacking. The driver itself has a fairly thick, rubber trim into which the 8 mounting screws are drilled. One can easily see the small gap between the MDF cabinet and the rubber trim of the driver. This internal portion of the cabinet is not painted or finished in any way, so it looks just a little bit cheap; as though the hole was cut and the driver was just plopped into the hole. A simple bit of extra trim to cover the gap would make the Sentinel look more "high end". Of course, with the grill in place, none of this is visible.

The 600 Watt amplifier is also flush-mounted. It is located on the back of the Sentinel and offers somewhat limited inputs and controls. There is a choice of either an XLR balanced input or an RCA unbalanced input. There are no speaker level inputs and no output connectors of any kind. There are actually two XLR inputs and two RCA inputs. One of each kind is strictly a "bypass" connection - labeled "LFE", which should be used if a receiver or pre-amplifier is controlling the cross-over between the subwoofer and the speakers. The second XLR and RCA inputs pass the signal through the Sentinel's internal cross-over. Two control knobs control the volume and the aforementioned cross-over (40Hz - 160Hz). A toggle switches sets the phase to either 0 degrees or 180 degrees and another toggle switch sets the power to either On or Auto. There is a "hard" power switch to turn off the amplifier completely. A two-prong IEC power inlet and a 110 Volt / 220 Volt selector round out the back panel.

The front grill is made of a black, plastic frame with plastic connection pins. Thin black material is stretched over the plastic frame. Connection to the front baffle of the cabinet is sturdy and does not move or rattle in any way. The grill does not cover the slot-port, but covers the rest of the front baffle's surface. The Epik logo is affixed to the bottom center of the grill.

Setup

My home theater is small: 12’ wide x 14’ long x 7.5’ high. It is enclosed, carpeted and treated with bass traps and absorption panels from GiK Acoustics. The Sentinel was placed atop an Auralex GRAMMA Isolation Riser and positioned close to the front, left corner. Upon powering the Sentinel, there is a very low volume hiss that is only audible within a few inches of the driver. The amplifier also produces a low volume hum. This is not a ground loop. It is thermal circuit noise - common with many power supplies. If you place your ear very close to almost any electronic device, you will hear some level of hum or whine. My listening position is a mere 7.6 feet away. At that distance, the very low volume hiss was completely inaudible, but the low volume hum from the amplifier was perceptible when all else was quiet.

I began my listening tests with 2-channel music in the form of CDs played with my Oppo DV-980H disc player connected via HDMI to my Onkyo TX-SR705 receiver as well as 256kbps AAC files played from my iPhone 3G. I would later move on to SACD recordings and then a live concert recording on Blu-ray. I concluded my listening with movies on Blu-ray. Connection between the subwoofer and the receiver was made with an RCA cable. I used the Onkyo receiver's crossover controls and thus, did my listening using the "LFE" RCA input on the subwoofer.

I regret that I do not have the proper equipment to provide scientific measurements. My remarks refer only to my subjective observations as I experienced them within my room. My previous subwoofer for many years has been the HSU VTF-3 Mk.2. Throughout my listening tests, I frequently swapped out the Sentinel and positioned the VTF-3 Mk.2 in the exact same spot on the same Auralex GRAMMA. While my small theater room obviously affects the sound that I hear at my listening position, this identical positioning ought to affect both the Sentinel and VTF-3 Mk.2 equally. Much of my criticism or praise for the Epik Sentinel's performance is based upon direct comparison to the performance of the HSU VTF-3 Mk.2 playing the same material at the same Sound Pressure Level. I used a Radio Shack SPL Meter to make sure the volume levels were the same between the Sentinel and VTF-3 Mk.2. An interesting aside: I found that the Sentinel's volume dial was consistently positioned about 1/6th of a turn higher than the VTF-3 Mk.2's volume dial in order to achieve the same output levels.

Prior to listening to any music or movies, I used test tones and a bass sweep to get an idea of the low end extension and linearity within my room. The Sentinel was immediately very impressive in how low it could play while maintaining close to the same output level as higher bass frequencies. The THX bass sweep - found on any THX disc that includes the company's Optimizer software - made it abundantly clear that the Sentinel maintained linear output considerably lower than my HSU VTF-3 Mk.2. In the 18 Hz - 25Hz range, I could feel the Sentinel pressurizing my room with a force that my VTF-3 Mk.2 most definitely could not match.

Listening Tests and Conclusion

Regardless of the source, the material or the recording quality, the story was always the same. The bass coming from the Epik Sentinel was very well extended and provided tactile impact and the "throbbing" sensation that comes from effective pressurization of the room. But everything had a slightly "muddy" sound to it. Bass notes did not stop as quickly as one would hear in a live performance. One note would "overhang" onto the next, creating a lack of clarity and articulation. Individual bass notes were not clearly delineated from one another. All of this created slightly distorted-sounding bass in music.

For movies, the deep extension and great tactile impact overshadowed the short-comings that were apparent with music. Explosions were thrilling and gave that wonderful effect of almost blurring my vision. And rapid gunfire seemed to physically hit me in the chest.

There was never any question: when the VTF-3 Mk.2 was playing, notes were clearer, better delineated and more articulate. There was simply less distortion coming from the VTF-3 Mk.2. On the other hand, it was equally obvious that the Sentinel played lower and with more tactile impact. Dynamics were also noticeably stronger coming from the Sentinel.

CD Performance (John Williams - Greatest Hits 1969 - 1999; Leona Lewis - Spirit; Smashing Pumpkins - Rarities and B-Sides):

John Williams' "Theme from Jaws" set the stage. The deep string bass and cello notes at the beginning had strong and clear fundamental tones, but some of the subtle texture was missing. It was difficult to picture the bows being drawn across the strings in my mind's eye. The notes were present, they were in tune and they were full-bodied, but they did not quite sound like real life instruments and each note seemed to linger for just a moment too long.  The same notes played through the HSU VTF-3 Mk.2 had more texture and gave a better illusion of live instruments. The clarity of the attack of each bass note was about the same. I would even say that the Sentinel made each attack a bit more prominent and distinct. But the decay of each note was definitely longer when played by the Sentinel. In the case of staccato bass notes, there was no gap - no "breath" - between each note with the Sentinel. The sound just continued, but with each attack sticking out to punctuate the sound. During the very quiet opening, I could just barely make out the hum coming from the Sentinel's amplifier. I found it very disappointing to hear any sort of noise floor what-so-ever.

Leona Lewis' "Bleeding Love" allowed the Sentinel to clearly outperform the VTF-3 Mk.2 in one specific way. About half-way into the song, there is an extremely low, synthesized bass note that acts as a transition to a new section. This note - as played by the Sentinel - hit with such force that it was literally startling! The VTF-3 Mk.2 basically did not produce this extremely low fundamental at all and only the harmonics were audible to indicate that anything had played in that instant.

Smashing Pumpkins' "The Beginning is the End is the Beginning" provided a particularly revealing comparison. The song contains intentional distortion, but also some very distinct bass passages. This track makes for an excellent test of a subwoofer's delineation capabilities as bass drums, synthesized bass effects and intentional distortion are all layered on top of one another. I was not able to distinguish each bass component and instrument when listening to this track with the Sentinel. It all sort of "merged" into a bit of a jumbled mess with only the most prominent notes and drum hits sticking out over the din behind them. The intentional distortion seemed to blanket everything. This was not the case with the VTF-3 Mk.2. With the HSU subwoofer, the distortion seemed to "hover" over the other notes, but each bass component and instrument was delineated and I could follow one particular section if I concentrated. Simply put, the VTF-3 Mk.2 offered higher fidelity.

256 kbps AAC (Justin Timberlake - FutureSex / LoveSounds; Ne-Yo - Year of the Gentleman)

I do not listen to very much hip-hop, R&B or rap, but I wanted to test the Sentinel with music that contained steady bass beats.

Justin Timberlake's "SexyBack" allowed the Sentinel to demonstrate its great ability to pressurize the room. The constant bass beat of this song gave me a "throbbing" and "pulsing" sensation that was lacking with the VTF-3 Mk.2. The effect was similar to being in a dance club, but without the absolutely deafening volume levels. The attack of every beat hit with more force and impact through the Sentinel. But, once again, the decay of each beat was longer. This affected the way I felt emotionally as I listened to the two different renditions presented by the Sentinel and the VTF-3 Mk.2. I will be very blunt here: with the Sentinel's sound, I felt slower and dumber. I began to feel a bit numb and I started to have difficultly concentrating. The VTF-3 Mk.2 more rapid stops after each beat made me feel more driven and alert.

Ne-Yo's "Mad" has a very simple bass section. There is rarely more than one beat or drum. With such simplicity, the Sentinel was able to sound clearer than with anything I had heard up to this point. Again, each bass note hit with greater force than the VTF-3 Mk.2 could muster.

SACD (Norah Jones - Come Away With Me; Steely Dan - Gaucho)

Norah Jones' "Don't Know Why" provided another example of the Sentinel's lack of texture and realism. The plucked bass notes had strong and distinct fundamentals, but the nuance was missing. The recording quality of this SACD is pristine and every minute detail is perceivable with speakers that are up to the task. The VTF-3 Mk.2, once again, sounded closer to real life with each bass note having more texture and character.

Steely Dan's "Hey Nineteen" was the same story. Each bass guitar note sounded a bit "slower", "fatter" and lingered for a moment longer when played by the Sentinel. The attack of each note was stronger and more pronounced, but the overhang of each note made the bass sound less lively and precise.

Blu-ray (John Mayer - Where the Light Is; The Matrix; Iron Man)

"Where the Light Is: John Mayer Live in Los Angeles" captures a three part, live performance in crystal clear Dolby TrueHD quality. The first section of the performance is primarily solo work, with nothing but John Mayer singing and accompanying himself on guitar. Throughout this section, the Sentinel made the performance sound "fuller" and "warmer". But the same section played through the VTF-3 Mk.2 delivered a clearer, more life-like sound. The second section of the concert is Blues/Jazz music played by the John Mayer Trio. Here, once again, the Sentinel was not as "tight". The bass guitar and drums had great impact and strong attacks, but each note lingered just a bit too long and served to "muddy" the detail. The final section of the concert is John Mayer in full Rock Band mode, playing hits from his album releases. With many more instruments, more crowd noise and louder, more dynamic music, the Sentinel delivered great slam, impact and pressurization, but also sounded less clear, less articulate and muddier.

The Lobby Shooting Spree scene from The Matrix made me both giddy and disappointed. On the one hand, when Neo punched the guard, I felt as though I had been hit in the chest with a tactile impact that the VTF-3 Mk.2 has never delivered! When Trinity first opens fire, the rapid gunshots hit with a tactile impact that I had not felt before. And as "bullet time" went into effect and Trinity cartwheeled off of the wall, the sound effect played with tremendous dynamics and I felt the room pressurize! On the other hand, the synthesized bass track playing behind all of the action was a bit of a mess. With so many Low Frequency Effects, the bass music and the effects all just sort of jumbled together most of the time and even the actual melody was obscured a little bit. The scene became just a cacophony at times and detail and clarity was lost.

LFE impact and dynamics are where the Sentinel really shines. The "Jericho Explosion" in Iron Man was truly something to behold as played through the Sentinel. The wave of pressure, rumble and tactility was greater than I had experienced in any full-sized movie theater and even topped my experiences in IMAX. Iron Man's repulsor blasts were absolutely thrilling as the Sentinel seemed to capture pure energy and deliver it directly into my chest.

Conclusion

Heading into this review, I had hoped the Epik Sentinel Subwoofer would take the great bass quality that I have with the HSU VTF-3 Mk.2 and simply extend lower and increase tactile impact. The Sentinel gave me the extension and tactility I had hoped for, but sacrificed some of the quality to which I had become accustomed. So it was a trade off: articulation and clarity for extension and slam. I have a much tougher time accepting any sort of distortion or lack of clarity and I therefore prefer the VTF-3 Mk.2, even though it does not play as low or deliver as much tactile impact. It comes down to a matter of trust. In every single instance with every comparison, I felt that I could trust the VTF-3 Mk.2 to play back the bass notes in music faithfully and without distortion.

Overall, the Epik Sentinel Subwoofer was a disappointment to me. It has its strengths: deep extension, good tactile impact, good pressurization and strong dynamics. The Sentinel was thrilling for movies, but I could not trust it to play back bass without imparting "colouration" of the sound in the form of a bit of overhang and distortion. It delivers the thrill of explosions that rattle your teeth and gunshots that “hit you in the chest” with tactile force. But for music, I found it lacking in articulation, delineation and clarity. Not only was the HSU VTF-3 Mk.2 obviously clearer and more articulate, but even without a comparison, the Sentinel reproduced bass notes in music in a way that simply did not sound like real life. If all you care about is shaking your seat and feeling the bass as much as hearing it, the Sentinel has that in spades for a relatively low price and relatively compact size. For my tastes, the clarity and articulation are not good enough. But for some listeners, the Epik Sentinel will satisfy certain aspects of bass reproduction better than comparably sized and priced competitors.

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Bass Extension
Bass Accuracy
Build Quality
Fit and Finish
Ergonomics & Usability
Features
Performance
Value