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September 2007
Enjoy the Music.com Review Magazine
Role Audio NSM15EXP Subwoofer
A Sub Of Another Color.
Review By Jeff Rabin
Click here to e-mail reviewer

  "I've always been mad, I know I've been mad, like the most of us...very hard to explain why you're mad, even if you're not mad..."


Role Audio NSM15EXP Subwoofer  There is a good argument to be made that subwoofers should be confined to computer desks, accompanied by pairs of plastic cased crap plastic full range drivers either side of the monitor tethered to a crap on board sound card. There's a lot of good content available on the net even if it's terribly compressed nature makes it sound less than good. And then there's Doom.

But while there's no good argument to be made for said same crap speakers this time five in number, the front two of which are also placed on either side of the TV with a black box placed inconspicuously conspicuously at best, such a state of affairs is such a sad state of sonic affairs is now so common as to not merit comment.

"Live for today, gone tomorrow, that's me, HaHaHaaaaaa!"

As good, albeit deluded friends, will say: 'just listen to that bass. And I would be a liar to suggest that not only did I like bass, there's bass, and then there's the kind of bass you hear in a club of the trouser flapping variety. This is the bass that hits you in the chest and slaps you right side of the head and asks you to take a sip of Evian from the one hand and wave your glow stick with the other.

But I don't think at least at home this is how bass ought to or to be perfectly honest can be.

Domestically speaking unless you live very much alone on a New Hampshire mountain top I suggest you should only hear 'that bass' when you go to the trouble of listening for it. Never should bass again, at home at least assault you. Indeed, for music a subwoofer ought to be like garlic, only noticeable for its absence. Movies are, however, a different kettle of fish. With very multi-channel content mixed very differently where the audio rather than an end in itself but as a supplement to to the visuals the purpose (and use it is put towards) is quite a bit different and I will only lightly touch upon it.

There is also the canard that a subwoofer may be placed anywhere.

I also won't even open the can of worms opened by Dr. Bose that two inch maybe they are larger drivers in cubes attached by spindly arms coupled to a 'discretely' hidden box (for which there is a premium to be paid) is all that is needed to bring Avery Fisher Hall home. I suppose I shouldn't grudge Mr. Bose, but I do. There is also that devil of a time seamlessly integrating a sub into a music own system.

What's worse, is all too often hi-fi systems are asked to perform two duties. On the one hand, they are asked to reproduce the experience of attending the cinema, on the other hand, the concert hall. None of these questions I endeavor to answer here other than to say twiddle knobs and experiment with placement until you are at least a little bit happy so that you may get down to enjoying the music.

"And I am not frightened of dying, any time will do, I don't mind. Why should I be frightened of dying? There's no reason for it, you've gotta go sometime."
"If you can hear this whispering you are dying."
"I never said I was frightened of dying."

I suspect these (and others) are the reasons that subwoofers have (often deservedly) garnered for themselves such as bad name. Personally, and really rather generally, I hate them. That said, I am not one of the British fraternity who believes that real bass gets in the way of PRAT. I like my speakers big and my coffee black. The NSM under review here and Axiom's EP500 Leviathan that I had the pleasure of previously reviewing are the grateful exceptions.

What then do I (and I suspect many others) have against subwoofers. I don't believe it is the concept as not only do few doubt that even the highest pitched instruments exhibit significant infrasonic content some of which is not as infrasonic as the purveyors of the full range driver crowd would have you believe. I believe it has to do with the way in which most subwoofers are sluggish, one note, and are most often designed to impress the home theatre crowd but with music quickly becomes unlistenable.

Not unlike Role's other speakers which in design and execution stray from the all too common norm, the EXP15 is a subwoofer of another color and none the worse for it. Quite obviously the EXP has been designed for listening to music and for matching with Role's other speakers but it does not let movies down either. Out of the crate, with its unusual front port and hidden driver it is quite obvious that the EXP is not your brother-in-laws' subwoofer 'just listen to that bass ' with an exposed front facing long throw driver, a puffing port, and an unfeasibly large amplifier.

Rather, Role's EXP uses a sealed rear chamber single driver bandpass cabinet design. Essentially, as  it has been explained to me,  it is a closed box design with an acoustic filter  the front placed ported chamber   positioned in series with the front of the driver. The chosen driver, rather than one designed for a ported cabinet, is of the sort more commonly driver used in an acoustic suspension or infinite baffle design. (It is quite obvious that the fine fellows at Role keep step by a different bassist.)

Another way of looking at it, according to Role, is to think of the subwoofer as built in an acoustic suspension cabinet with the woofer mounted within and a supplementary cabinet in front of the driver that is itself ported. In the 15 EXP, the sealed rear chamber is in the upper section of the cabinet. This unusual arrangement accounts for the unusual dimensions of the EXP, in that unlike most subs it is significantly taller than it is wide.

Inside, a 10-inch long throw driver of undisclosed provenances aims directly down. The front cabinet (which is actually below) acts as  both an  acoustic filter as well as a vent channelling sound into the room. The sealed rear chamber cabinet acts as an acoustic bandpass filter coupled with an electronic, adjustable crossover giving a slope of about 12dB per octave.

"HuHuh! I was in the right!"
"Yes, absolutely in the right!"
"I certainly was in the right!"
"You was definitely in the right. That geezer was cruising for a bruising!"
"Why does anyone do anything?"
"I don't know, I was really drunk at the time!"
"I was just telling him, he couldn't get into number 2. He was asking why he wasn't coming up on freely, after I was yelling and screaming and telling him why he wasn't coming up on freely. It came as a heavy blow, but we sorted the matter out"

The merits of the closed rear chamber single driver bandpass design are, according to Role, that a very flat bass response over an extended range of frequencies analogous to a bandpass crossover filter response, a sealed rear chamber provides a far quicker transient response than would be available in a conventionally ported response. The "natural" response of the cabinet is augmented by the 12dB per octave crossover of the subwoofer amplifier. The front mounted vented acoustic filter produces lower bass and more efficiency than you would get from the typical acoustic suspension system. Such efficiency counts for what goes today for the rather modest 150 watt rms amplifier. 

"I mean, they're not gunna kill ya, so if you give 'em a quick short, sharp, shock, they won't do it again. Dig it? I mean he get off lightly, 'cos I would've given him a thrashing - I only hit him once! It was only a difference of opinion, but really...I mean good manners don't cost nothing do they, eh?"

As Erol Ricketts wrote me, 'Whatever magic you hear from the 15EXP is the evolution of a passive design from the days when the performance of a subwoofer depended on the relationship between the woofer and the cabinet and not as it is nowadays by electronic [DSP fiddling.]' While, with reason, Mr. Ricketts knows far more about speakers than I will ever know, 'magic' is not the word I would use but I am probably wrong. Arthur C. Clarke famously wrote that 'Any sufficiently advanced technology is indistinguishable from magic' and I did find the EXP quite a bit easier to integrate into my system than has been my previous experience with subs.

"I can't think of anything to say except... I think it's marvellous! HaHaHa!"

Although we are not here speaking of a Tardis and I have little faith that the EXP will tell me tomorrow's trifactor in the 5th at Woodbine there is something distinctively unsubwoofery about the EXP that I happily lived with. (If you haven't caught on by now, I have ever only once before met a sub I could love, much more happy to do with less or even no bass than bad bass.) The EXP did not so much guild the lily or draw undue attention to itself as it put meat (but little fat) on the bottom line making cellos more convincing, drums more striking, and even vocals more realistic.

This is not, however, a subwoofer for the trouser flapping brigade with its design remit clearly aimed at being an adjunct to the main speakers than a sonic laxative in its own right. Indeed, in a design that pays more to acoustics than digital jiggery, the EXP weirdly, and the better for it, harkens back to an earlier age where short cuts in design could not be pasted over by software. I have (almost) always believed that a mature older technology such as late model valve Leaks will run circles around a newer but immature one and I believe this is what we have here.

Some other details: Along with the conventional 150 watt amplifier and 10-inch long throw driver the EXP has a phase reversal switch, switches itself off and on in the presence or absence of a signal, has of course a volume control, but also a continuously variable crossover control with an unusually wide range. Along with both line level and speaker level inputs, it has both speaker level outs as well as unusually a line level out which can be used for ganging another subwoofer without having to twiddle the supplementary subwoofer to match. At the rather reasonable MSRP two such subs are not outside the realm of the practical.

As a fillip to the home theatre crowd and in these days audiophiles much to their chagrin of many audiophiles who have often enough have had to sate the family with dual purpose systems our friends at NSM have placed a significant frequency response bump at 35Hz. In practice and I am slightly embarrassed to note this as it does nothing for my listening cred I never really did notice the 35Hz bump. I strikes me as a rather good idea, particularly for the action movie crowd. The embarrassing fact that I never noticed may either be down to the subtlety of the bump (a mild 5dB according to the manufacturer), the room, or my choice in music and movies. It strikes me that my noticing the bump shows a judicious choice on the part of the designer characteristic of how well thought out Role's products are. Moreover, and in my support of my thesis, the subwoofer rolls in thankfully gently quite a bit higher than is the norm.

While I had the sub in my greasy paws, I played quite a variety of material through it playing disc after disc of obsolete multi-channel SACDs and the occasional DVD-A (well, actually I only have three, and the one that rhymes with Bed Smepilyn was execrable and the other two were of music that I doubt I will ever have a taste for). SACDs were a different matter. Multi-channel SACDs are still rather an immature medium, unlikely to mature in fact, but I have been snapping them up at bargain prices I often find them wadged in among the CDs at CD prices in my local soon to vanish polycarbonate emporium. Sometimes they get the multi-channel mixes correct, frustratingly often, however, they don't.

Call me an old fogie, but I will take front row seats over sharing a stool with the drummer any time. Indeed, on more than one occasion I have felt the icy glare of a guitarist berating me for not knowing before they did how they wanted their guitar tuned. Thankfully, not yet anyway, has security had to usher me off stage or worse backstage for the after party. Who would dare say no to Roger the Hat Manifold?

One bit of fun I have been enjoying is going through all the versions of Pink Floyd's Dark Side of the Moon I have, not only having spent 741 weeks on the chart, but album that did most for autistic hi fi among us (shame about the clocks). Somehow I have acquired a 4 channel mix in DTS on DVD, an SACD/CD hybrid, a bog standard CD, a stretched cassette, a poorly cut mid eighties Mississauga pressing., a wonderful reggae version by the Easy All Stars and I have even been given to understand that there is an acappella version. What I don't have is either a 4 channel reel to reel or even a quadraphonic lp though I would have no way to play it, SQ or otherwise. And while all my copies are rather obviously of the same recording session, they all sound really rather different, particularly when it comes to the bass and that haunting heart beat that opens and closes the album, which in this roundabout way I come back to the review. In other words, Dark Side of the Moon is a very fine way of listening to bass and with each and every recording of DSOTM I listened to I could clearly hear the differences. While the Easy All Stars Dub Side of the Moon was merely phat, the lower registers of The Moon played through the EXP were downright menacing. This loonie was tempted to stray from the path.

Editor Steve adds: Yopu can never have too many versions of DSOTM. Have the original and anniversary CD, SACD, DVD, picture disc lp, and vinyl versions including original Harvest UK pressing, US pressing, MoFi standard and UHQR, German Quadraphonic, white Holland, and had the Japanese 'pro' version but someone stole it from my collection, Had the British quadraphonic version but that, too, seems to have disappeared.

Another embarrassing aside: Erol Ricketts, ex amateur racer and head honcho at Role, was rather concerned that I hated the sub as I had barely mentioned it in my original review of a complete Role multi-channel system. My reticence in fact had more to do with the unfeasibly fulsome bass of  the Role Enterprises and while I knew the Role sub was doing its job, it never, for well for ill, drew undue attention to itself which subwooferingly speaking is undoubtedly no bad thing.

As a test of my own auditory sanity once I had the levels set within what I took to be hi fi reason I experimented with switching the sub in and out of the system. While the difference switched on and switched off was unmistakable the difference was not so remarkable as to suggest that you had seriously cocked up set-up. While I enjoyed that certain extra and fulsome extension (for music anyway, for movies, particularly of the action sort, was a different matter) that the subwoofer provided, I could live without it. While that indeed sounds like faint praise, I do not mean it that way.

What I mean to say is that the EXP's satellite brothers have such tuneful, transmission line bass (double transmission lines in the case of the Enterprises!) with the subwoofer so obviously built with its sister speakers in mind that where the satellites ended and the subwoofer began neither the floor standers or the improperly located coffee table painted in a mottled, unobtrusive subwooferingly speaking black end and began without drawing attention to either. Both the satellites and the subwoofer were conspicuous by their absence, really as it should be.

'There is no dark side of the moon really. Matter of fact it's all dark.'

NSM's (AKA Role Audio's) EXP15 Subwoofer is not a Subwoofer for the head banging brigade. It won't flap your trousers, it cannot be used as a weapon, nor will it turn your bowels to water at 30 yards and 30 cycles. What it will do is enhance your existing system with greater bass extension and present a more realistic window into your source material without ever drawing (undue) attention to itself. It's aim and remit is to compliment but not to overshadow. The EXP is the invisible personal assistant whose presence goes unnoticed but whose absence is a crisis. The EXP is garlic, enhancing the flavor of the dish, only noticeable by its absence, but will not keep the vampires at bay.



1.) While it's still listed, there's a wonderful BBC documentary on Syd Barrett to be found here. I would add, merely to brag, that Roger Barrett and I both used to live in Camberwell and that it has always been an inspiration of mine to see out my final days in Cambridge.

2.) My 'off the grid' system has on a tethered tuner now run for over 36 hours without a hiccup.



Sub-bass (10Hz - 60Hz)

Mid-bass (80Hz - 200Hz)

Midrange (200Hz - 3,000Hz)

High-frequencies (3,000Hz on up)




Inner Resolution

Soundscape width front


Soundscape width rear   N/A
Soundscape depth behind speakers N/A

Soundscape extension into the room


Fit And Finish

Self Noise

Value for the Money



Type: Self-powered subwoofer with crossover.

Driver: 10 inch long throw

Amplification: 150 watts

Inputs: Line level (RCA) and loudspeaker

Outputs: Line level (RCA) and loudspeaker

Adjustable output level

Continuously variable crossover

Crossover: 12 dB per octave.

Bass boost of 5dB boost at 35Hz

Phase: adjustable

Auto-on (and off) sensing is user selectable.

Dimensions:  12 x 18 x 15  (WxHxD in inches)

Weight: 55 lbs.

Price: $995


Company Information

Role Audio
P.O. Box 13396
Research Triangle Park, NC 27709

Voice: (919) 244-8777
Fax: (206) 339-9034
E-mail: roleaudio@hotmail.com
Website: www.roleaudio.com













































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