Music in the Round #88: SPL Volume 8 and SMC 7.1

I have not been attending audio shows as often as I used to, and this January, for the first time in more than 20 years, I'm skipping the annual Consumer Electronics Show. My personal return on investment has become hard to justify, especially when attendance at each annual CES requires a round trip from New York City to Las Vegas, Nevada. More important, audio shows now seem focused mostly on either two-channel music playback or multichannel home theater, whereas what interests me is listening to music in surround sound. Sure, I can be excited by the introduction of new speakers and new power amplifiers, which have obvious application in any music system. On the other hand, the vast majority of analog preamplifiers and DACs are two-channel only, while preamplifier-processors and audio/video processors emphasize their video facilities and such sound options as Dolby Atmos, DTS:X, and Auro-3D, none of which has much impact on music, yet.

And in disc players, there's a widening gap between the stereo-only audiophile market and the larger, HDMI-only home-theater market—and that leaves me and Oppo Digital alone in the middle. Most servers, too, seem to serve up mostly stereo.

This is not a happy situation for me, because audio shows, both national and local, give me valuable opportunities to hear good sound and music, often provided by experienced professionals. Every listener adapts to the sound of that listener's system, dominated as it is by the acoustic of that listener's room, and it's okay to accept and enjoy the resulting experience of music without constantly questioning it. On the other hand, if you're committed to optimizing your listening experience—and if you're reading this magazine, you probably are—you need to periodically refresh your ears and challenge the sound you've grown accustomed to by hearing other systems. Not all show demos are satisfying or useful, but many are interesting and refreshing, and it is such experiences that can trigger a serious reassessment of your own system.

I always attend the frequent manufacturer-sponsored events at Innovative Audio, a Manhattan dealer, and as I write this I look forward to two major events here: the Audio Engineering Society Convention (October 18–21) and the New York Audio Show (November 10–12). Still, the most valuable opportunities are to visit kindred spirits and hear what can be called a curated system, as in this definition of the word I recently found on "to pull together, sift through, and select for presentation, as music or website content." A perfect example was when, on my way to a Bowers & Wilkins press event in Boston last summer, I visited with Tom Caulfield.

Tom Caulfield is a Grammy-winning recording and mastering engineer who has been responsible for many of the outstanding multichannel recordings released by Chandos, Channel Classics, and Yarlung. In addition, he's a tireless champion of multichannel DSD with minimal processing. For some years now, Caulfield has also been seducing many in the audio press and elsewhere with some of his remarkable private recordings, made during commercial recording sessions but using his own microphones and mike placements (footnote 1). I believe that he helps many of us keep a clear ear on the cutting edge of modern recording technology.

While I've enjoyed meeting Caulfield several times at industry events, as well as at one of his recording sessions, this was our first opportunity to talk at length, and for me to hear what music sounds like through his undoubtedly unique mastering system. The system dominates an upstairs room in his house, where five large Sound Lab Majestic 645 full-range electrostatic speakers, each 75" high by 34.5" wide by 7.5" deep and weighing 140 lbs, cluster closely around a comfy stuffed armchair. Together, they form an almost pentagonal enclosure in the center of the room, but because of their proximity and the fact that each speaker radiates sound from its entire surface of 1790 square inches, they "disappear" acoustically, providing a nearly transparent window on the music. There is some other furniture in the room, as well as acoustical treatments and spare Sound Lab panels, but again, with the proximity of the speakers to the listening position and the limited amount of reflected rear radiation that can reach into the enclosure, the room acoustics only minimally affect the sound. Caulfield played files from his server, which he accesses via his mastering software and routes to five Parasound Halo JC 1 monoblocks, one 400W amp per speaker, via a set of relays that permits assessment of individual channels, combinations of channels, or the entire 5.0-channel array.

I'd brought a number of familiar files with me, and Caulfield's server contained many more. Sitting in this sound capsule and with all my other senses isolated from external distractions, I felt an immediate connection to the music, and was aware of no spatial discontinuities. I could easily perceive subtleties of width and depth in the soundstage, and hear extended, detailed treble completely devoid of highlighting or brightness. Comparing really good commercial recordings, all high-resolution and 5.0-channel, with some of Caulfield's unreleased recordings using his own mikes and placements, I entirely appreciated his preference for closer miking, for a closer perspective on the performance. There was an exhilarating intimacy to the performances, even more than I'd realized when I played them at home. I also appreciated why Caulfield's system is so marvelously suitable for his mastering work. No detail is lost, and the crucial relationships among the channels is surgically revealed. That my experience was thrilling should be no surprise—these recordings were mastered on this very system. How could they possibly sound better anywhere else? This experience, and Caulfield's conversation and hospitality, affected me deeply—and left me impatient with Bowers & Wilkins's two-channel demonstration the following day.

Back home in Manhattan, it was clear to me that I would not like to live in the hothouse of Tom Caulfield's sound capsule. With its gripping intimacy came a proximity that seemed to intrude on my personal space, especially with his closely miked private recordings. I didn't feel comfortable listening from the conductor's podium (I did try it once)—the excitement simply overwhelmed the attention I was trying to pay the music. I am a listener, not a performer, and Caulfield's recordings sound more realistic to me through my own system. Still, my time with him raised my listening to a new level of sensitivity—which I will now apply as I focus on some imperfections in my system.

SPL Volume 8 and SMC 7.1
It's no secret that there are very few analog control options—for volume and input selection, primarily—for multichannel, but that doesn't mean there are none. Parasound's excellent Halo P 7 is the only analog multichannel (7.1) preamplifier currently on the market, but since there has been no relevant new technology since the first round of multichannel analog preamps from the first decade of this century, one can consider any number of good used products from the multichannel exuberance of more than a decade ago. I own an Audio Research MP1, and there are others worth seeking out from Bel Canto Design, McIntosh Laboratory, and McCormack Audio. Fundamentally, all that are needed are input switching, volume control, and, perhaps, the ability to balance channel levels. Old hat.


The studio/professional market does offer some analog multichannel devices. There are lots of complex devices that incorporate multichannel switchers, analog input and output, and analog volume control, along with a plethora of mixing features, but finding something with the appropriate feature set and cosmetics is difficult. About a year ago, I discovered a device from Sound Performance Labs (SPL, footnote 2): the Model 2489 Surround Monitor Controller, which supports two six-channel inputs (one balanced), two stereo inputs (unbalanced), and one six-channel output (balanced). It also has a volume control with a discrete (ie, each channel is on its own physical deck), six-layer potentiometer. Unfortunately, the 2489's single balanced input connector is a DB25, its output jacks accept only ¼" TRS-wired phone plugs, and I found its looks decidedly unappealing. I let it pass.

Recently, SPL introduced an array of new products aimed at getting the German company beyond the pro-sound market and into the homes of tech-savvy audiophiles. I found two relevant products, either of which would add a physical volume control to the output of a multichannel DAC. The first is the Volume 8 ($699), which incorporates SPL's discrete six-layer potentiometer in a neat black enclosure with an eight-channel balanced input and an eight-channel balanced output: a volume control in a box. The other is the SMC 7.1 Surround Monitor Controller ($1899). It adds to the Volume 8 a second eight-channel balanced input, two pairs of XLR stereo inputs, a stereo XLR output, an XLR subwoofer output (a full-range mono sum of the L/R stereo inputs), a headphone jack, two outputs for metering, and an array of illuminated pushbuttons. Both the Volume 8 and SMC 7.1 have Mute buttons. Hooking up either requires the purchase of two DB25 cables, sometimes described as fantails, which break out into eight individual XLR connectors as input or output. Audio Plus Services, SPL's US distributor, sent along two 1m-long, multipair Sonorus Muco DB25 cables made by the Swiss company Vovox. The DB25-to-XLRx8 male and XLRx8-to-DB25 female cables ($699 each) are beautifully constructed, with solid-core copper conductors for all three lines (positive, negative, and ground), and don't rely on a braided shield for the ground. And despite consisting of eight balanced lines each, they are also remarkably flexible.

Footnote 1: You can get a taste of this by downloading a copy of a session outtake of the first movement of Mahler's Symphony 3, with Iván Fischer conducting the Budapest Festival Orchestra. If you can play it, select the multichannel DSD256 option; it's the unedited original made with an optimized 5.0-channel microphone setup:.

Footnote 2: SPL electronics GmbH, Sohlweg 80, 41372 Niederkruechten, Germany. Tel: (49) 2163-98340. Fax: (49) 2163-983420. Web: US distributor: Audio Plus Services, Tel: (800) 663-9352. Fax: (866) 656-0686). Web:

Glotz's picture

I really wish Audio Research would produce an updated MP1 in the future. I thought that component was the most revolutionary product of that era. The way it brought instruments to the fore and still produced excellent depth of soundstage was a real ear-opener. The only way I could do surround, but obviously this product above would do much the same, only with less noise.

Kal Rubinson's picture

Agreed. For many reasons, I would much rather have an updated and quieter MP1 but that is not a real option.

retro's picture

Hello Kal!

Always enjoy your column..just wish they come more often..:)

You have compared more or less all the analog multichannel preamps. How does the tubed Fosgate stand up to the others, I know you reviewed one way back..?
Yes, I own one..:)


Kal Rubinson's picture

I was impressed with the Fosgate back then but it is just a memory for me now. At the time, I wanted to keep it but thought it beyond my budget. Today, frankly, I would not consider any tubed preamp in my system as I do not want any added flavor, sweet or not.

retro's picture

Aha, Mr. Rubinson don't like tubes..;)

Thanks for your reply!

Kal Rubinson's picture

Sorta but sorta irrelevant. There are no modern multichannel vacuum tube preamps to consider.

Mike-48's picture

Kal, Interesting reviews as always. Do you think the SPL Volume 8 sounded better over time because of warm up? Or the contrast to your system without it? And if the HF glint was gone, does that suggest the Volume 8 might be slightly rolled off? Or that its output drivers are smoother than those used before?