Review (August 2002)
Includes the SS-250 Tripole® Surrounds
By Kevin Nakano
Home theater speaker systems have become so popular over the years that virtually all speaker manufacturers now offer 5.1 systems. High-end companies that once frowned upon the idea of having their audiophile speakers combined with televisions are now meeting the demands of those consumers willing to pay for them. Finding the best system for your dollar is a time consuming process and becomes very subjective to say the least. Many of us rely heavily on product reviews to steer us in the right direction or possibly even look to those who are part of the professional recording industry. After all, the media we listen to passes through the systems these professionals use in their day-to-day work. If the latter weighs on your decision, you may be interested to find that many of the audio professionals rely heavily on M&K speakers for their monitoring systems. Over the past few years I've had the opportunity to visit several commercial facilities involved with the production of A/V software content for consumers. Most of these locations have systems that for good reason would be considered reference quality for mixing and producing audio for multi-channel recordings. The interesting part is that the vast majority of these locations have M&K THX certified speakers installed for monitoring the audio. One should not be surprised given M&K's reputation in the industry. Companies such as Dolby Labs, Digital Theater Systems (dts), 20th Century Fox, Skywalker Sound, and THX Division - Lucas Film LTD are just a few of the names who benefit from M&K speaker systems.
The reference S-150THX speakers are the consumer version of the ones found in the professional studios around the country. Our setup consisted of a pair of S-150THX speakers and one S-150AC center channel. The "AC" designation for the center channel stands for "Angled Center". All front channel speakers as well as the subwoofers are THX Ultra certified. The rear SS-250 surround speakers are similar to the S-150THX design with four additional drivers (2 + 2) firing forward and backwards into the room. This design (called Tripole®) radiates sound timbre matched with the front channels, while providing the dipole effect with sound surrounding the listener. For the ultimate in bass reproduction, we used a pair of MX-350THX Mk II subwoofers each having a built-in 350 watt RMS amplifier.
The second version is the standard center channel (ordered as the S-150C), which has a squared front baffle, with no horizontal or vertical angle. This speaker has additional magnetic shielding through M&K's high-performance Ferromagnetic Shielding System.
The third version is a variation of the second with an Angled Center channel (ordered as the S-150AC). This speaker's front baffle is angled 7.5 degrees in the vertical plane to aim its high frequencies either up or down, depending on the cabinet's orientation. We used it on top of a rear-projection television pointing downward. This aims the high frequencies at the seated listeners even though we found that we had to use an additional wedge to get the angle just right. This speaker also uses M&K's Ferromagnetic Shielding System. Depending on your needs, you could actually use three Standard Centers or three Angled-Centers for all three front channels. For example, if a perforated screen is used in the front, one may prefer the Standard Centers for all three channels. However, if the speakers will be in a wall unit above listener's head, three S-150ACs pointing downward work out better. The point is M&K offers the user or installer many options to maximize audio performance.
We used the Sound Alignment - System from Checkpoint Laser Tools to help us take the guesswork out of setting up these speakers. The 770-laser alignment unit attaches to the front of the S-150 speaker pointing exactly 90 degrees from the front baffle. All one need to do is turn the laser on and you will see exactly where the speaker is pointing. We also used Checkpoint's Inclinometer to measure the angle of the rear surround channels. We'll talk more about these products in a separate review.
Mk II Tripole®
We exercised both the dipole and tripole modes to hear the sonic differences. What we found was depending on the source material one configuration worked better than the other. When the rear material was more ambient in nature, we liked the dipole mode. Sound didn't appear to come directly from the surround speaker, but rather spread around and behind us. In contrast, DVD-Audio 5.1, DTS 5.1 and multi-channel SACD material sounded the best when we ran the SS-250s in the direct radiator mode. This gave us the best timbre match with the front speakers. Ideally we would like to have five identical channels for most of the DVD-Audio and DTS music we listened to. However, the third (Tripole®) mode radiates sound from the front as well as the sides for the best of both worlds. We currently have our surrounds setup in the tripole mode and it seems to be the best all-around configuration for most material. Since this speaker offers different configurations, the user has the option of changing modes with a simple switchbox. We plan to implement an external relay to switch modes for us based on source material.
Low-pass Filter - The low-pass filter control can be set to one of three different settings. The first is the THX mode, which bypasses all low-pass filtering in the subwoofer and completely relies on the THX controller to provide the low-frequency signal to the subwoofer with the 80Hz and 24-dB/octave crossover characteristics. The variable mode allows the user select the best crossover frequency for his/her setup with a variable control. The third setting is a fixed 80Hz and 24-dB/octave low-pass filter built into the subwoofer.
Bass Level - The bass level can be set to two different settings depending on the type of processor used in the system. The THX mode is a fixed level of 90dB with a 100mV RMS input. When using a THX certified processor, the THX mode should be utilized. The variable mode allows the user to adjust the level of the subwoofer using the variable control. When using the variable mode, the setting marked Reference is the same level the THX mode uses.
Bass EQ - The Bass EQ switch has two settings, THX and Extended. The THX setting produces the flattest response and is recommended for most installations. The Extended setting produces a flat anechoic response, which results in an increase in level below 30Hz due to room gain. This increase is about 12 dB/octave. The Extended setting is provided for measurement purposes and for those who might want this sonic profile. However, this setting limits the subwoofer's output and dynamic range.
Phase - The phase switch is used to control the phase of the subwoofer output. There are two positions, "+" for in-phase and "-" for inverted-phase. The only way to know what the best setting should be is to try both and determine which position produces the highest level output. Positioning of the subwoofer as well as room dimensions affect the desired phase setting.
As with several of M&K subwoofers, the MX-350THX MKII includes the Active Headroom Maximizer circuit that prevents the all too common clipping associated with overdriving. We didn't use the internal low-pass filter because our THX processor took care of this for us. As a result of using the 80Hz crossover frequency built into the THX processor, the subwoofer blended seamlessly with the main S-150 front channels.
One of the advantages of these THX-Ultra certified speakers is the narrow vertical dispersion, which helps prevent floor and ceiling reflections. Reflective surfaces introduce secondary arrivals of sound that, when combined with the direct sound from the speaker, blur and defocus the image. To help dampen our listening room we have the walls treated with Echo Buster sound absorption panels. In addition, we have a pair of Echo Buster bass absorbers in the front corners of the room. Fortunately, our acoustically treated vaulted ceiling further reduces unwanted reflections. The narrow vertical dispersion of the S-150THX speakers works well in rooms that have reflective surfaces. We could hear significant differences in the upper frequencies if we moved outside this vertical window. Due to the driver arrangement on the front baffle along with the crossover design, we found the S-150s very consistent at all seating positions (horizontally) within the optimal vertical window. This uniformity provided us with excellent response in our home theater environment.
What sets this M&K system apart from so many speaker systems I've listened to is the ability to play them at high volume levels without the fatigue often encountered with lower priced speakers. While less expensive speakers can sound wonderful, they usually lack the ability to play at high volumes and still sound good. The overall performance of the S-150THX proved to be reference quality for home theater applications as long as time was spent to properly set up the system. These THX Ultra certified speakers are not forgiving if the alignment is not directed straight at the listener. This is why both THX and M&K endorse the Sound Alignment - System from Checkpoint Laser Tools as mentioned earlier. These tools help pinpoint the alignment of the front baffle to ensure the best high frequency response from the highly directional loudspeakers. A significant amount of time was spent setting up the speakers and the laser alignment tools took out much of the guesswork for us. Once the system was properly aligned, the results were spectacular.
We ran through the paces with scenes from Pearl Harbor in DTS. The attack scene on the harbor has been one of the industry's favorite surround demonstrations this year and we can see why. Planes moving through all corners of the room gave us a sense of reality few systems are capable of. The dialog was crystal clear with perfect intelligibility, never sounding overly bright. Sounds panned seamlessly throughout the room without any distractions. The Tripole rear channels were highly effective in providing a timbre matched to the fronts channels while spreading the sound around the back and sides. The low-end impact from the explosions was handled with ease by the MX-350THX subs. The two 12 inch drivers per cabinet moves an enormous amount of air and still has the ability not to sound muddy. The bass reproduction was tight and articulate as we have heard in the past with this push-pull design. Our Sencore SP295 Audio Analyzer confirmed the low frequencies we heard/felt showing substantial levels of bass in the 20Hz region.
While movies are a large part of how we use our speakers, music is equally important in any practical environment. The S-150THX speakers certainly hold their own against any home theater system we've heard. Certainly there are tradeoffs with any speaker system and if we were to buy speakers solely for listening to music, there would be many to choose from. However, the results of listening to several multi-channel DVD-Audio and SACD recordings with this system proved to be very satisfying. The new high-resolution 5.1 discs really push the edge when it comes to multi-channel high-resolution recordings and with these speakers we heard subtle details that overwhelmingly impressed us. In our opinion, the new DVD-Audio and multi-channel SACD recordings offer consumers a whole new level in audio performance. Since Warner Music has aggressively introduced remixes of some of the best groups of the 70's, much of our listening was based on this material. Fleetwood Mac's Rumors was a classic two-channel recording and the new 5.1 mix is superb. In addition, the Eagles' Hotel California was a great demonstration of the artistic creativity that goes into these new multi-channel recordings.
It's not surprising that JAK Productions used M&K speakers for their sound design and picture editing suites for the Star Wars films - The Phantom Menace and the recent release of Attack Of The Clones. Compromise in sound quality on films such as these is not an option and that's the primary reason why so many professional studios around the country are currently using M&K speakers.
The performance of this system went well beyond any home theater speaker setup I've experienced in the past. The pinpoint accuracy and clarity of the front mains, especially at high volume levels, was an exceptional experience. The matching surround channels with the addition drivers for the Tripole effect proved to be highly effective while watching movies. Listening to both DVD-Audio and multi-channel SACD enveloped the room with five high-quality channels with little compromise. The low frequencies handled by the MX-350THX subwoofers blended seamlessly with the mains, giving the listener a realistic full range system. While this system is not cheap (close to $10K retail), the performance coupled with M&K's reputation in the professional industry, may very well justify the cost. To further tempt you, M&K offers solid build quality and an impressive warranty (ten years, 5 years on the subwoofer amplifier) . We've had this system running for months now and we never get tired of listening to it.
- Kevin Nakano
See the latest MK Sound S-150 System Review
|Review - At a glance|
Miller & Kreisel S-150THX
Speaker System |
SS-250 Mk II Tripole®
MX-350THX Mk II Subwoofer
Source: Manufacturer Supplied
Source: Manufacturer Supplied
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