Since the dawn of this industry we work in or are fans of, two of the leitmotifs driving the research and development of the equipment used over the years have been: achieving the greatest fidelity in capturing sounds and then reproducing them, and having that reproduction in turn convey the position of the recorded sounds in space. We went from monaural systems to stereo systems and, over time, to multichannel systems, also known as surround sound systems. It should be noted that the engine of this entire revolution was the film industry, where surround sound systems with a number of independent audio channels were developed, enabling an incomparable viewing experience, with effects and soundtracks traveling across the room from one end to the other.
As a bit of trivia you can find by poking around online, one of the first productions to feature surround sound was Walt Disney’s “Fantasia” (1941), which used four audio channels. Over time the number of independent channels grew, its use extended to the home with the arrival of so-called home theaters, and music also adopted the system, both for live recordings and for studio productions (though less often).
Multichannel Sound
The most common surround system is known as 5.1, which is regulated by the International Telecommunication Union’s ITU-R BS.775 standard, which refers to a 3/2 stereo system with three front channels L, C and R (left, center and right) and two rear channels Ls and Rs (left surround and right surround). Optionally, it provides for extending low-frequency reproduction by adding a sixth, independent channel for that purpose. Compatibility with systems with fewer channels is ensured, and the mix can be played back on two-channel stereo systems and even mono systems (through channel-decoding math that is of no great interest in this test).
That standard also regulates the ideal arrangement of all the speakers for optimal listening. Imagine a circle with the listener at its center, facing 0º. The speakers are distributed so that the L speaker is at -30º on the circle, the C at 0º, the R at +30º, and the Ls and Rs at -110º and +110º, respectively. This arrangement, with the listener seated right in the center (the so-called sweet spot), means the sounds are received from speakers that are all at the same distance, so no delays or phase shifts are perceived between the signals reproduced by the different transducers. Needless to say, all the cabinets should be at the same height (with a little leeway), and that should be approximately the height of the listener’s head.
As you can guess from all of the above… the problems start already. Setting up an ordinary home room following all these recommendations is not within everyone’s reach. Not in terms of means or knowledge and, fundamentally, because many people find it excessive that to watch a “flick” or a live concert recording, the placement of the furniture in the living room housing the home theater has to be dictated by the speakers. It’s not even common to see a stereo pair set up properly!! Fortunately, many of the products on the market today let you introduce delay times into the signal reaching the speakers (individually) to adjust for differences in the distances between them and the listening position.
To wrap up this introduction to multichannel sound, I should mention that there are two 5.1 sound formats on the market: Dolby Digital and DTS Digital Surround, which, without going into much detail, differ in how they encode the six audio channels. As a result, the data transmission rates per second differ (in favor of DTS), which some experts consider makes it a higher-quality system. In Dolby Digital’s favor is its universality on all commercial DVDs.
Both systems have superior formats as evolutions of the originals, adding one more channel, up to 6.1, which feeds the speaker that would be placed in the rear center position. It is a virtual channel, since it does not correspond to an independent audio channel but is generated from the information in the Ls and Rs channels when the receiver decodes the DVD audio. These are the formats known as Dolby Digital EX and DTS Extended Surround (DTS-ES), which maintain backward compatibility.
Evolution doesn’t stop, and with the advent of high-definition television (HDTV) and its associated media with greater storage capacity (HD-DVD and Blu-ray), new multichannel audio formats are being developed with more independent audio channels, higher transfer rates and, ultimately, higher quality.
And we, as part of the business, must be prepared to produce the sound material properly, so that it makes it into whatever format and the end consumer plays it back as faithfully as possible to what was intended. Without a doubt, we need a surround monitoring system that guides us and lets us emulate what will happen in a commercial or home viewing room. Today we put two good proposals for mid-sized work environments to the test: one from JBL and one from Genelec.
Bass Management
Before discussing our impressions of the two systems, let’s introduce a concept about how home systems usually handle multichannel sound. The most critical part of speaker placement is the part affecting the perception of low end. In principle, the five speakers of the 3/2 layout can work full-range, that is, reproducing the entire audible spectrum, if they are capable of it. Since an unplanned placement of five sound sources reproducing low frequencies can cause serious phase problems, the situation could arise where they partially or even totally cancel each other.
One way to avoid this problem, without driving yourself crazy looking for the ideal positions, is to use the sixth channel, the one intended for low frequencies, which in film is used to send very-low-frequency effects and increase the sense of realism in explosions, earthquakes and all sorts of similar effects. It is therefore called LFE (Low Frequency Effects) and is reproduced by a subwoofer. In music it handles the lowest parts of the mix. The idea is that, since low frequencies are barely directional, the other channels don’t need to reproduce them, leaving all that work to the LFE, which receives the signal to be reproduced from the receiver, where you find what is usually called a bass management system.
In reality, bass management can be found in the receiver or in the subwoofer, and standalone units that perform this management externally are also sold. It is usually a user-activated system and is slightly adjustable (whether or not the satellites are filtered, the crossover frequency). In essence, when it is enabled, the system filters the signal going to the five channels (front, center and rear) with a high-pass at a frequency that usually ranges from 80 Hz (as in the THX standard) to 120Hz and, simplifying, sends the rest of the signal to the subwoofer. Since a large part of today’s equipment works this way, it is important for us, the people responsible for the mix, to be able to monitor how our material will behave on a home system with bass management enabled. This, as we’ll see later, is a fundamental part of the two systems that will go through our test bench: both incorporate a bass management system.
JBL System: LSR4328P and LSR4312SP
These monitors are old acquaintances. JBL’s LSR line has been extensively tested in the pages of this magazine, both the LSR63XX and the LSR43XX families. Not long ago, I myself did a review of the LSR4328P model in a stereo configuration, and it came out very well. Without going into the detail laid out in that article, it is worth recalling the fundamental features.
The LSR4328P is a bi-amplified monitor with an 8” woofer cone and a 1” tweeter, with 120 W and 70 W amplifiers respectively, and it benefits from three JBL proprietary technologies: LSR (Linear Spatial Reference), which aims to guarantee flat listening within a relatively large window (±30º horizontally and ±15º vertically); second-generation RMC (Room Mode Control), which adapts the monitor’s response to the room where it is placed; and the intercommunication protocol linking all the monitors, called HiQnet. Up to eight cabinets in a room can be interconnected with standard RJ45 Ethernet cables, bridging from one cabinet to the next and placing the two terminators at the ends. Once the cabinets are connected to each other, and having indicated each cabinet’s position in the configuration (whether L, C, R, etc.) with DIP switches on the rear panel, and connecting an RTA (Real Time Analyzer) microphone to the front left cabinet, we can run the RMC and watch in amazement as the cabinets automatically apply EQ correction to adapt to the room’s imperfections and correct the partial levels of each monitor so that optimal listening is achieved at the point where we placed the microphone.
All of this, which was already a great help for configuring and tuning a stereo system in a room without costly acoustic studies, becomes fantastic given the complexity of installing a 5.1 system. In addition, the whole system can be controlled via a remote control, with access to all the configuration options the cabinets allow (bass roll-off, bass and treble attenuation, DIM function, custom EQ curves…) and what’s more, it can be connected via USB to a computer which, using JBL’s specific software, called Control Center Software, lets you manage everything from there, with the advantages that brings, such as being able to store user memories.
Besides the five LSR4328 monitors, which take the front and rear positions, the system is completed by a subwoofer from the same family, the LSR4312SP, which shares everything described above with the other members, plus a few particularities we’ll see now. It is a self-powered (450 W) subwoofer with a 12” neodymium-motor driver and a paper-polymer cone, with a frequency response from 27 Hz to 250 Hz and a digital crossover tied to bass management, selectable at 50, 80 or 120 Hz, 4th-order (24dB/octave). The rear panel has all the analog and digital audio inputs and outputs, the two RJ45 connectors, a USB connection, a switch to select the input signal level (+4 dBu, -10 dBV), a switch to increase the subwoofer’s gain by 10 dB, a group of DIP switches (to select digital inputs, change polarity and tell the system whether a second subwoofer is present) and, finally, a set of LEDs indicating the input and digital channel in use.
As you will have noticed, I’ve been talking about audio inputs and outputs, and that’s because the LSR 4312SP is where the computer that handles bass management resides, so the six signals we send to our monitoring system pass through this unit and from there to each of the corresponding monitors. This way we can get a reference for how our material will sound on a home system just by enabling or disabling bass management mode from our remote control or computer.
Genelec System: 8030A and 7060B
Likewise, Genelec’s 8000 series has also been through these pages. Specifically, the 8050A and 8040A models were the subject of reviews by me and by our colleague and contributor Ramon Sendra. The 8030A is the model immediately below, also bi-amplified, with a 5” woofer cone and a ¾” tweeter, with 40W amplifiers for each driver and the crossover set at 3 kHz. It shares the rounded-shape design of all family members, along with the two technologies that represent the value of these monitors. We’re referring to MDE (Minimum Diffraction Enclosure) and DCW (Directivity Control Waveguide). The first refers to the curved enclosure design, which keeps the reflection of the signal off the structure itself from generating more than one source of sound, with the definition problems that entails. The second technology applies to the shape of the tweeter’s seat (a small depression), improving sound directivity, which translates into a flatter frequency response from the monitor, especially at the listening position. It also shares with its bigger siblings the curved design of the bass-reflex port tube, reducing distortion and improving the low-end extension of the whole.
On the front panel, at the bottom, is the on/off switch, along with a volume control for the unit, a feature that betrays its orientation toward home studios or small production studios, where there probably isn’t a console with a control room section.
On the rear panel, next to the power inlet and in an inverted horizontal position, are the XLR audio connections, in this case analog only. We also find a set of DIP switches with which we can attenuate the highs above 15 kHz by 2 dB, the lows at 100 Hz by 2, 4 or 6 dB and, finally, apply a bass roll-off from 85 Hz at 6dB/octave, ideal when these monitors are used in a stereo configuration with the family’s small subwoofer, the 7050A. However, for a multichannel setup using the model under test as satellites, Genelec recommends the 7060B subwoofer, which is the one we received.
It is a unit with a 10” driver, a 120 W amplifier and built-in bass management, which handles 5.1 or 6.1 systems. The enclosure is built with LSE (Laminar Spiral Enclosure) technology: a sheet of metal rolled into a spiral and attached to an MDF (medium-density fiberboard) structure, creating a curved reflex tube that provides, according to the manufacturer, excellent laminar flow (the air moved by the driver generates no turbulence), and it is large for the overall unit. The bass management system sits on a damped structure, to isolate its operation from possible vibrations.
On the side panel are the audio inputs and outputs (all analog) for the six channels (L, C, R, Ls, Cs and Rs), plus the LFE input and its output, for chaining to another subwoofer. We also find a pot that adjusts the unit’s sensitivity, an RJ11 connection for the remote control, an LED indicator of activity and operating mode, and a couple of groups of DIP switches. With one of them you can select whether the unit manages the bass or the system works full-range (and the signal above the crossover frequency is redirected to the center monitor), whether a low-pass filter at 85 Hz or 120 Hz is applied, whether the LFE level is raised by +10 dB, and the last one enables/disables the test tone, for perfect phase alignment. The other group holds the DIP switches that determine whether an 85 Hz roll-off is applied in three steps of -2 dB, and the buttons for changing phase in 90º steps, along with use of the aforementioned test tone.
The Test
The truth is that the listening tests themselves confirmed what we had already found at the time. The cabinets acting as satellites sounded as we expected.
Given how different the LSR4328s are from the 8030As, there is no comparison to be made. That was not the goal. The JBLs are of a size and power suitable for studios that need nearfield with high SPL, or midfield without too many power demands. The 8030As are intended for nearfield, broadcast rooms and home studios. In their respective spheres, both are a superb choice for quality, reliability and sound. The significant part came when we started to evaluate them as part of a multichannel system, to which we added their corresponding subwoofers.
The first thing we did in both tests was set up the physical placement of the cabinets. We put them in the proper positions, wired the audio from the patch bay to the subwoofers and from there to their respective monitors. It should be noted that this was much more complicated with the JBL system than with the Genelec, since, in addition, we had to interconnect all the cabinets with the RJ45 Ethernet cables, configure the DIP switches to tell the system where each one is located, connect the RTA microphone and the computer via USB to the front left cabinet, install the software and run the RMC. Of course, the result justified all the extra work, since I still find the RMC’s operation impressive, the way it adjusts the monitoring response to the room at the listening position (which is where we place the RTA microphone).
Once everything was configured, we opened a 5.1 session of Miqui Puig’s live show (soon to be released), which we recorded at the time and had just mixed for the DVD. This session also contained a stereo track from the CD mix, which let us make stereo vs. 5.1 comparisons with the same cabinets. We sent the mix to the systems with bass management disabled, the idea being for the satellites to work full-range and the subwoofer to extend the low-end response. The result was that the JBL setup suffered from excess low end and a certain lack of definition right where definition matters so much, between 100 and 200 Hz. By comparison, the stereo without subwoofer was “smaller” but at the same time more intelligible. By playing with the bass attenuation controls we achieved a certain balance, but everything still sounded a bit “fat.” With the Genelec system, and given that the monitors are smaller, that feeling was not so pronounced; in fact, the body the combination provided was welcome, and by comparison, stereo listening through the 8030As felt like too little.
Time to enable bass management on both systems. The first thing we did was undo all the adjustments we made in the full-range test, to start from scratch. This noticeably improved the listening with the JBLs; all that lack of definition disappeared, and the typical LSR4328P sound gained a sub-bass extension, making the whole really pleasant. The stereo without sub fell behind, in this case. As for the Genelecs, the slight impression of excess low end also disappeared, but it ended up sounding wonderful when we set the subwoofer’s crossover filter at 120 Hz instead of 85 Hz, as if that filled in the overlap zone more consistently. My impression is that to mix multichannel music with the 7060B, it would be more advisable to use 8040As or even 8050As.
Conclusion
Since my studio isn’t a video post-production facility, I couldn’t compare the systems with any material other than strictly musical. And although the natural territory for surround sound is film, more and more live concerts are being mixed in 5.1, and even electroacoustic music productions play creatively with the six independent channels. In any case, both systems did their job very well, proved very reliable, and the mix results translated very well to the home theater world. My opinion is that what sets them apart, beyond particulars of coloration, is the segment the products target and, fundamentally, the incredible ease of setup that RMC provides on the JBL. Although it will no longer be exclusively theirs, since Genelec has started selling the 8000 series in a DSP version with a large number of configuration options and auto-calibration. It’s a case of keeping up with the Joneses…
And one more thing. Once you see the role the bass management system plays, despite the limitations it may pose, its inclusion in home systems is a marvel, allowing everyone to enjoy surround sound at home without problems.
