Velodyne SMS-1 Subwoofer Equalizer
User Review

Last updated 5/30/2006



I ended up with an SMS-1 as an unexpected Christmas gift – it was suggested by Scott Jackson at Outlaw Audio as a good complement to the Outlaw Audio Model 990 surround processor that I got back in the late spring, and my wife was kind enough to write a check for it. The SMS-1 is a product from Velodyne that transplants the Digital Drive room correction hardware and software (developed as part of some of their subwoofers) into a standalone chassis. The name stands for "subwoofer management system" and it does just that: manages the subwoofer signal to achieve a flat frequency response by applying equalization. Equalization for subwoofers and even entire surround speaker systems has become a hot topic recently, with a number of manufacturers including automatic equalization systems for at least the low frequency portion of the audio output, but the real challenge to manufacturers has been achieving this equalization in such a way that it provides some real sonic benefit. Automatic systems can attempt to do this, but some people would prefer to have direct control – introducing both a great deal of compexity into the user interface and the potential for user adjustments that unknowingly endanger speakers. When Outlaw released their Model 990 processor (based on the Sherwood P-965 chassis but with some interesting additions), they included automatic setup for channel trim levels, speaker distances, and bass management, but they could not find a cost-effective EQ solution that satisfied them. Instead, they began offering Velodyne's SMS-1 through their site for $599 in the fall of 2005, just in time for the holiday shopping season. When my wife exchanged a couple e-mails with Outlaw (where I'm fairly well known due to my presence as "gonk" in their online forum the Outlaw Saloon), Scott offered the SMS-1 as a good addition to our system. As with my other reviews, there's an equipment list at the end of this review.

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My first thought on seeing the box on the front porch was "what is that?" My second thought (upon recognizing the model number and realizing what it was) was that it seemed like a mighty big box for such a small device. The SMS-1 component itself is small (standard 17" width but only 2" high and 6" deep) but very solidly built. Accompanying that module in the double-boxed packaging are a number of other goodies: IEC power cord, AC adapter, remote control, and a large cardboard box full of accessories. These accessories include stereo analog cables and a composite video cable for connecting the unit to a receiver or processor (necessary to allow the unit to generate test tones and display its menus and frequency sweeps) and the SMS-1's "ears."

Accessory box, microphone, stand, and mic cable

Those "ears" consist of a very beefy microphone (provided in a foam-lined plastic carrying case along with a microphone stand bracket and a dust cap), a short microphone stand, and a long microphone cable. I'm not a conniousseur of microphones, but this one is extremely nice – a hefty aluminum body and XLR connection. The provided A/V cables went into my system, while everything else stays in the accessory box when not in use.

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While the accessory box stayed near at hand, the included remote (a UEI remote based on the same shell as the Catalyst48 universal remote used with receivers and processors such as Outlaw's 990, 970, and 1070, Anthem's AVM-20, and others) went to the desk so I could program its commands into my MX-700 universal remote (my configuration file is available here). Once that was done, it was retired to the drawer at the bottom of the entertainment center with all the other remotes stored there (at last count, there were at least a dozen remotes in there). The SMS-1's remote is nicely laid out and thoughtfully provides clear labels for all of the presets, but it is not backlit. Since most of its use will be during configuration (when there's no real reason to have the lights off), this seems to be a sensible decision. The online manual's picture of the remote is low resolution and very difficult to read, but the printed copy included with the unit is very clear.

The front panel has a minimal set of controls: power button, IR sensor, display screen, front microphone input, and volume up/down buttons. Aside from hooking the mic up during setup, I don't expect to use the front controls often. I'm leaving it on all the time currently, although I may get fancy and use the 990's second trigger output to turn it on when the 990 comes on. The display can be toggled on and off with the "LIGHT" button on the remote. When on, it is quite legible but also quite bright. People who take their light control seriously (such as with systems that use front projectors) will want to become acquainted with the "LIGHT" button, as I could find no setting to permanently turn the display off. Personally, I haven't been bothered by the display. The top line of the display shows the volume setting and the active preset number. Mute and night mode are indicated on the second line when they are active, as is the automatic EQ mode when it is running.

The bulk of the user interaction with the SMS-1 takes place through the on-screen menu system. This menu offers access to a number of settings as well as a continuously repeating frequency sweep. There is also an automatic setup mode that will run a series of sweeps and determine the appropriate settings for you. The menus score high on the "cool" meter from this geek's standpoint (live frequency response curves for your system are pretty impressive), but the method for entering different areas of the menu is a bit odd. To get into the main menu, you press "MENU" and then "12345" in sequence. To get into the auto setup mode, you press "321" in sequence. To reset the unit to the factory defaults, press "890" in sequence. I wouldn't have minded a top-level menu (activated with the "MENU" button) that led you to different areas and used a "yes/no" confirmation prompt if appropriate (such as resetting to factory defaults).

What does this user interface get you? For that, we'll move on to the setup process.

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The SMS-1 module's rear panel is pretty crowded for such a theoretically simple device. From left to right the back panel offers balanced LFE output and input, a rear microphone input, an IR input, RS-232 input and output (for linking multiple SMS-1's, connecting to a control system such as Crestron, and updating the unit's onboard software), composite and s-video outputs (for the on-screen display), three identical unbalanced subwoofer outputs, EQ output (for the test tone output), "thru" outputs (used to share an input with multiple SMS-1 units), high-pass outputs (using the 80Hz crossover), two unbalanced inputs (for LFE or line-level left/right channels), 12V trigger, speaker level inputs, and a 12VDC power connection. Out of all of that, I used one unbalanced LFE input, one unbalanced LFE output, the EQ output (connected to Video4 on my Model 990), the composite video output (also connected to Video4 on the Model 990), and of course the power connection. It is possible to connect the microphone cable to the rear input and leave it in place all the time, but in my case I simply used the front input. And since the SMS-1 is so shallow that it could sit on top of the Model 990 without blocking any ventilation openings, I tucked it in right on top of the 990.

The main menu (or "System Settings" screen) offers a wide assortment of adjustments. All six presets are listed along with a "Setup" option that will be applied to all six presets (so you can set the crossover frequency, phase, polarity, slopes, and so forth globally without adjusting each setting six times). The low pass crossover frequency can be set in increments of 1 between 15Hz and 199Hz; highlighting the crossover frequency and selecting "Reset" on the remote will disable the crossover and change the crossover frequency and slope to zero (good for folks who already have their bass management handled at the surround receiver or processor). Low pass crossover slope can also be set to 6, 12, 18, 24, 30, 36, 42, or 48 dB/octave (or zero if the crossover is disabled). The subsonic filter can be set in increments of 1 between 15Hz and 35Hz to establish a lower limit on the frequencies sent to the sub; subsonic filter slope can be set to 6, 12, 18, 24, or 48 dB/octave. Phase can be adjusted in fifteen degree increments between 0° and 180° (handy for those of us whose sub offers only a 0° or 180° phase switch). You can also switch the polarity from positive to negative, which mimics the behavior of the typical 0°/180° phase switch. A volume control allows you to define a boost or reduction in bass for different presets; as the master volume changes, the individual preset volumes change to match. Each individual preset has a separate contour frequency and contour level. The frequency selected will be boosted (or reduced) by the value specified in the contour level. These are preset at the factory but can be adjusted by the user. Other options in the System Settings screen include the default preset (the preset that comes up when the unit is turned on), 12V trigger mode (defaults to inactive, but can be changed to active if a 12V trigger cable is connected), and night mode volume percent (which determines how much reduction in sub volume is applied when in night mode). I left the 12V trigger inactive since I an planning to just leave the unit on all the time. I left the default preset alone initially since I wanted to get through the calibration first, and the night mode setting was left at the default of 30%. The low pass crossover was set to OFF in order to disable it (my Model 990 handles my bass management needs), which made the low pass crossover slope irrelevent. The subsonic filter defaults to 15Hz and 24dB/octave, but I changed it to 21Hz and 48dB/octave to quickly drop off the sub's workload as it moved out of the range for which my sub is best suited. This is one setting that I may tweak a bit over the coming months, but some back-and-forth suggested this to be a good spot. In fact, the subsonic filter may have yielded as much benefit in my system as the equalizer, since it helped my sub (which is tuned to 25Hz) deal with some very hot and low LFE tracks. Phase and polarity allow you effectively unlimited control over tuning your sub in, which I did not make all that much use of but could be a huge help in a system or a sub placement situation where 0° or 180° phase adjustment is insufficient. I've been leaving the volume at around 10 with the sub amp's volume control set at around six o'clock and the sub trim at the processor at -2dB. It is convenient to quickly adjust your sub volume without getting into the processor's menus (the only way to adjust the 990's sub trim) or reach behind the sub, and the scale used by the SMS-1 appears to not be in 1dB increments (changing from 15 to 16 is on the order of 1/2dB or less change in volume). The contours are basically what differentiate the presets; since I use only the "custom" preset, I haven't tried to adjust them or listen to find what differences are produced by adjustments to the contour frequency and level – and I suspect most users will simply use preset 5 (custom, with no contour adjustments) most of the time anyway.

After a little aimless wandering through the menus and some tweaking in the System Settings menu, I gave the automatic setup process a spin. This was a relatively quick process, with a series of twenty-five test tone sweeps. When it was done, the resulting curve still had some dips in it. Rather than adjust what it had already done, I elected to take a shot at doing it entirely by myself. After zeroing everything back out, it was time for some manual sweeps.

One of the first things I did with the manual sweeps was to experiment with my crossover setting choice. To my surprise, I was able to get a smoother response by raising the crossover point for my mains from 60Hz to 80Hz. In the past, I had used a lower crossover (40Hz with my SVS 25-31PCi and 60hz with my Outlaw LFM-1) to help blend the sub and mains together cleanly for music. With the EQ, I could move the crossover a greater distance from the -3dB point of my mains and control the sub to smoothly blend it in with the mains. I made all of my changes to the preset "setup" (so that the EQ settings were applied to all five presets), using a trick pointed out to me in the Outlaw Saloon by jongaro: the eight EQ's can be moved to specific frequency positions that need the most attention. It's mentioned in the manual, but I missed it until I went looking for it specifically. When adjusting an EQ, you can press "select" and it will allow you to adjust not only the L (level in dB), but also the F (frequency in Hz) and Q (measure of how much a given equalizer affects a range of frequencies). I shifted several EQ's to different frequencies to target specific dips or peaks. One thing to be wary of when doing this is what the SMS-1 manual refers to as "stacking" – placing two EQ's at the same frequency and boosting both to their maximum level can create a situation where the subwoofer is asked to work far harder than it is designed to and can potentially damage the sub. Think of it as running your sub as much as 12dB "hot" over a narrow portion of the sub's range, and it may be easier to understand the danger associated with stacking.

It took me a little time to get a handle on the different presets. The user has the option of treating each preset as a completely different set of equalizer settings (different EQ settings, different volumes, different crossover and subsonic filter), but in general the "setup" preset is used to apply settings like crossover, filter, and EQ to all five presets. Only the contour frequency and level are specifically assigned independently to each preset. It is these settings that define the different presets (action/adventure, movies, pop/rock, and jazz/classical) in the unit's default configuration. It would be easy for a user to create one preset for movies and one for music with different subsonic filter, volume, or even EQ curve if it were beneficial. Personally, I set preset 5 ("custom") up and have left the SMS-1 set to that preset. I did toggle between preset 5 and preset 6 (the bypass mode, which disables all functions of the SMS-1 except I think the volume) during my testing to see what differences were audible.

Update 5/30/2006: There are two useful bits of information to add to this review. First, Velodyne recetly released a firmware update (available from the Velodyne site or from Outlaw's SMS-1 page). The update is version 2.12, which replaces the original firmware version 2.10 (the firmware that originally shipped with the SMS-1). This new firmware adds one thing: the ability to set the subsonic filter as low as 5Hz – nearly the same thing as disabling it, something that neither firmware version supports. I don't currently have any plans to install this firmware since I've actually got my subsonic filter set a few Hz above the previous low limit of 15Hz. A second useful bit of information comes straight from Outlaw Audio. They watched the discussions on their forum and made note of the tech support calls they received, and they used that information to help prepare an Outlaw's Guide to the SMS-1. This document basically gathers all of the operational details available from the original Velodyne manual, tosses in some suggestions and commentary from Outlaw, and serves it all up in a convenient format. One comment from my original conclusions was that the documentation could have been organized better – The Outlaw Guide appears to do just that. I highly recommend it to anyone considering an SMS-1 and to anyone who already owns one.

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I had the unit in place for a couple days before getting a chance to seriously dig into manually adjusting the presets, but during that time I had little opportunity to listen to anything (TV, DVD, or music) with much low frequency extension – between the brief automatic setup and the bland content played, I withheld any observation as to the effectiveness of the SMS-1 until I got it dialed in. Once I had gone through the manual calibration described above, I started throwing everything I could find at it. These listening tests included both movies and music.

I pulled several movies off the shelf to give the SMS-1 something to chew on. Attack of the Clones, Revenge of the Sith, Finding Nemo's fishtank tap, and the space battle in Serenity (which arrived at almost the same time the SMS-1 did) all had turns in the Oppo. There was somewhat greater detail in the audio during several passages in the asteroid chase (chapter 28) on Attack of the Clones, and the opening space battle in Revenge of the Sith seemed a bit clearer as well. The fishtank scene still leaves me concerned about my house's foundations. Most interestingly, however, was chapter 15 of Serenity – the sequence in which Serenity leads the Reavers into the middle of an Alliance fleet. With preset 5 ("custom"), the bass was consistently somewhat clearer and cleaner and the overall sound smoother. With preset 6 ("bypass"), the sound seemed a bit mushier, especially as Serenity flew through the Alliance fleet and later in the atmosphere as it pulled out of the flat spin and landed. I played that sequence at -5dB volume on the 990 (which I don't recommend if your cold has left you with a good headache, but still enjoyed) and was quite satisfied with the results. I may still tweak my settings a bit, but so far my results are quite satisfactory.

The music that I tried out tended to be good bass material: Blue Man Group's DVD-Audio discs "Audio" and "The Complex," Tantric's self-titled CD, and whatever else was handy. The benefits are not necessarily as immediately apparent on music as on movies due to the tendency to include such deep-reaching bass in movie soundtracks, but some of the discs I was trying did yield a bit smoother presentation in the low frequency ranges. Tantric was one that I suspected would give the SMS-1 some work to do, and I was correct. Likewise, both Blue Man Group discs of course included some very low frequencies. All three presented sequences (the opening minute or so of the first track of Tantric and much of the last tracks on "Audio" come to mind) where the preset 5 yielded cleaner sound and what I might call a "tighter" or better defined bass. It's not necessarily night and day in my space, which happens to present a relatively inoffensive acoustical environment (due largely to chance, luck, and unrelated decorating preferences), but I can see where "problem" spaces could benefit more significantly.

Velodyne SMS-1 sitting on top of Outlaw Model 990.

Since the SMS-1's purpose was addressing the lower octave bands, I tried to evaluate it with an assortment of material that offered up a healthy dose of low frequency kick – almost all of it (Serenity being an exception) material that I was familiar with on my system before the SMS-1 entered the scene. As I've noted, the results were positive. It took a bit of reading and research to get a good grasp on exactly what the SMS-1 is capable of (and I feel certain that I have more to learn in that regard), but the results of that research and the setup process were rewarding.

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Setting up the SMS-1 was an unusual experience for me, partly because it arrived unexpectedly (meaning I hadn't done much research into it) and partly because it is not quite like any piece of gear I'd used previously. The interface is straight-forward and effective once you understand what it is doing, but the documentation could have been organized in a more effective manner and the menu access "number strings" could have been discarded. Once set up, the SMS-1 will generally need no attention from the user unless you want to toggle between a couple different presets – personally, I have settled into leaving it on preset 5 all the time. Once you get a decent way up the learning curve, the SMS-1's capabilities are really pretty exciting and the results can be impressive - likely more so in spaces with more significant nulls or peaks than my den produces, but even in my fairly well-behaved space there were improvements to be had.

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[an error occurred while processing this directive] hits since December 27, 2005 | Home Theater and DVD | Equipment Reviews