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REVIEW: REL Acoustics Strata II Speakers Review by Stephen at Audio Asylum

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Posted by Stephen on August 17, 1998 at 07:46:51:

N-I-M-S —————

N-I-M-S = NOT IN MY SYSTEM
Had you asked me anytime in the last three years if I would consider adding a sub to my stereo kit, my response would have been an unreserved “N-I-M-S,” and, (a somewhat reserved) “not in my lifetime.” Several efforts to integrate a sub-woofer into my system when I was running Vandersteens, Magneplaners and (the most current) Dunlavys met with continually mounting frustration and (to put it kindly) limited success.

If, by some stroke of luck, the sub could approach a successful match- up with the mains tonally and rhythmically, the active cross-over invariably mucked things up by adding grain, haze or other forms of insidious noise. To be totally truthful, none of the ones I tried (Hsu, M&K or Velodyne) met the mark on both of the above.

My most recent foray into the nether-world of subs came about as I found my system peaking in performance over the last year. With cabling selections completed in conjunction with the upgrade of digital front-end and power amplification, came significant (and telling) improvements across the system that pointed to the next step. I considered new speakers, but given the deal (read: steal at half-price for a mint-demo pair) I got on my SC-IIIs, I felt hard-pressed to go to the $6,000 - $12,000 mark for the Dunlavy family’s bass extension. (For those of you who have followed my meanderings, you will recognize that the purchase price of the bigger speakers themselves would translate to a real-world cost of $12,000 to $24,000 once the spousal-unit tax was factored in. That was more than I could handle this year, thank you!)

Anyway ... after many queries among folks who frequent this and other such forums, a lot of reading up on numerous designs philosophies and re-visiting basic sub theory, I arranged to have several subs delivered via UPS (they love me .... they love me NOT!) to casa de Stephen for review. Frankly, I expectation was that NONE of them would work out. My previous experience told me that sub-woofers requiring an active cross-over to perform in my system would quickly be dismissed. Those selected showed some promise for the ability to integrate without such a device. The short-list wound up looking like this:

M & K 125 $1200 (1050 + 8% tax after negotiations)
Paradigm Servo 15 $1400 (1200 + 8% tax after haggling)
REL Strata II $1200 (850 +8% tax upon finding an
“inadvertently opened box” with full warranty;
next best price was from Ambrosia in LA, for
$1050, delivered to WA state)
ACI Titan $800 (non-negotiable, direct from factory)

To speed things along, let’s just say that after dialing in the Titan and the REL, the M & K and Paradigm were taken out of the running—after relatively brief auditions—primarily because they were unable to match up tonally and rhythmically with my current system. Recent experiences in selecting a center channel for the HT set-up in the family room served me well in narrowing the field based on the tonal criterion. While the Titan and the REL showed promise for further integration, the others did not (your mileage in your system may vary). My patience—which was already running short after two weeks of lugging all these heavy suckers around—may have been a factor that came into play here, as well.

The REL was a pleasant surprise (in terms of sheer physical weight and room-placement-friendliness). The technical support from Sumiko (the distributor) was outstanding, and an education in itself. Several calls to the distributor, before purchase and during set-up, lasted more than forty minutes. This may explain why the mark-up on RELs is so high in America, when compared with the retail prices in the Far East and Europe. ;-)

SET UP —————

• Getting the REL dialed in actually took the better part of a week after burn in. Admittedly, I had not had a sub in my system since several failed experiments with Hsu, M & K and Velodyne about three years ago. In a nutshell, the biggest flaw I found in common with each of them was that the hi-pass cross-overs supplied with these subs consistently and significantly degraded the sound. That, when combined with the Hsu’s boominess (and finicky placement requirements), the M & K’s (a baby version, I must admit) lack of extension and the Velodyne’s “mechanical-sounding” nature, turned me off and literally left me wondering why ANYONE would EVER purchase a sub-woofer.

• The thing that got me interested in the REL was the ability to use a speaker-level connection (directly from the amp to the sub) andthe ABC network that allows the homo oddiofool Sapiens to dial in the crossover anywhere from 120 to 30 Hz. While it offers other connection options, the speaker level input enables the REL to receive the full, carried forward, character of the entire system. I thought this to be a bit of marketing hype when I originally encountered the concept. Even as Stirling Trayle (from the distributor, Sumiko) talked me through it, and it seemed to make sense, my natural cynicism remained. Oh, but to be proved wrong. My previous reference for what the SC-IIIs were capable of (in terms of deep, taut bass) came from its pairing (prior to the insertion of the CAL Alpha DAC and C-J 11a in the system) with the Sunfire amp. While the bass response with the Sunfire was a bit “synthetic” (as in: too tight to be real ... literally defying the “feeling absolute” because the acoustical wave/vibration was just too short compered to the real thing) it spoiled me when contrasted with my tubed amp’s abilities in the nether regions. I’ll get over it.

• The reality is that the speaker-level inputs performed just as promised, providing a much more synergistic connection than theline-level option.

• Upon listening, I quickly eliminated crossing over at 57, 53 and, with a bit more experimentation, 47 Hz as possible cross-over settings.

• Some of my peers questioned my initial cross-over choices of 43 and 39, thinking it was much too low. But, I got the flattest response in the 50 to 80 region using the 39 Hz setting; crossing over at 43 gave a bit of boost at these frequencies; depending on the production quality of the media, I found myself switching back and forth; settling in at 39 also slightly extended the depth and volume of the lowest 20 Hz region.

• That said, it gets even weirder, my friends. While the response was relatively flat at 39, the artifact of a 6dB drop at 20 was not one of the reasons I was contemplating the purchase of a sub. After numerous e-mail exchanges with Jack G (thanks again for the input and the encouragement to keep experimenting, Jack!) and then checking in with Stirling once more, it was decided that a move of the sub to the other side of the room AND another drop in the cross-over frequency were in order. “You think I should cross it over where? ... At 33! ... Are you nuts?! ... Well, I’ll try it ... but it’ll never work.”

• Guess what? It worked big time! I have to agree with Sumiko’s contention that most audiophiles (out of sheer over-intellectualization) tend to set the cross-over too high AND (out of fear of overwhelming the mains) at too little gain. I would have never suspected that 33 would be the best setting. Based on my mains, my initial guesstimations would have suggested 57, 53 or 47 Hertz.

Given that, prior to the insertion of the REL, the speakers were rolling off from -2 at 50 to -7 at 43, the bump from 60-80 (when run sans sub) offered a welcome degree of weight to the presentation. With the sub in the system, I preferred to remove this emphasis by repositioning the speakers.

Subsequent measurements showed:

• The REL was relatively non-critical of placement in my room. It was quite happy tucked away in the corner behind one of the mains.

• Use of the line-level inputs proved interesting: the net effect was to diminish the deep bass extension; frequency remained essentially flat to 63 Hz and then consistently dipped by 2-3 dB at subsequent lower frequencies when compared with the speaker-level inputs.

• Phase adjustments proved to make a big difference. When run out of phase with the mains, the output at lowest frequencies dropped by 8dB; in the 50 -90 Hz range, I would find peaks of 2 - 10 (yes 10) dB when I ran the sub with the phase reversed.

• Moving the sub from one corner (behind the mains) to the other corner boosted the 25-60 Hz realm by 2 -3 dB. Given the odd shape of my room, it made sense that the sub loaded the room quite differently from different corners.

THE IMPACTS —————

* Music selection listed below in addendum.

• The clarity of mids and highs improved even though no high-pass filter was used to reduce range of frequencies fed to mains.

• Brass exhibited more bite and body.

• Vocals had more clarity ... a level of articulation and projection I have not experienced before in my system.

• Guitars sounded more like ... erm .... uh ... guitars (I hesitate here, because many of the sonic contributions I will attribute to the sub are supposed to be (at least I was indoctrinated to believe) a result of using a hi-pass filter and freeing the mains of their lower-frequency responsibilities ... these improvements came despite NOT using any sort of filter ..
.
• The soundstage became somewhat wider (depending on the recording) and deeper (on most all recordings).

• A subjectively wider dynamic range that allowed for “getting the big picture” at consistently lower volumes.

• Hearing the fundamentals of harps, low range of piano, string bass and percussion brought a realistic sense of venue and (I believe) accuracy to many records and cds.

• The sense of space on analogue recordings increased dramatically, as did the dimensionality of various instruments and performers.

• Pianos ... guitars ... did I mention pianos or guitars? As a player of each instrument, I was duly impressed ... ‘nuff said. Weight, scale, blah, blah, blah.

• Extreme bass was present only when it was really in the music and it never overwhelmed the mid-range. No overhang or boominess was detected.

• The downside: the “enhanced” clarity of the midrange and treble can, on occasion, reveal production flaws and lead to some listening fatigue reminiscent of my experience with less-than-stellar solid-state amplification.


As I write this, the comparative “speed”—which to my way of thinking is more an issue of successful/seamless frequency integration, than actual “speed”” per se—of the REL sub is an unknown... I do expect the Titan to arrive shortly. I am very curious about how this sub will sound, given that it is a an acoustic suspension design and offers triple the power (a necessity given the sealed enclosure). While the REL makes no claims to be flat to 20Hz, the Titan does. It also boasts a “Q” very close that of what one gets with the acquisition of a pair of Dunlavys. Could it be a match made in heaven?

Stayed tuned.


THE ACI —————

When I received the ACI Titan. I was immediately impressed with the apparent build quality and looked forward to hearing it my system. After burning it in for 80 hours, I began experimenting with placement, crossover and volume settings. I used the speaker level inputs. I was a bit disappointed about the difficulty of setting gain and crossover. The knobs are SO tiny, that making small adjustments is extremely difficult. I'd highly recommend slipping some larger knobs over these to facilitate such adjustments.

After burning it in for 80 hours, I plopped it in the corner where the REL previously sat. Not bad for starters, but ultimately, I located it between the mains just behind and two feet away from the left speaker. This gave the smoothest overall response. Smooth, but far from flat.

My initial impressions:

• punchier and tighter than REL? Is this due to hearing a pronounced mid-bass?

• maybe a touch faster than the REL, but does not strike me as being as tonally-correct or more refined

• improved the sense of recording/performance space, but not to the degree (and accuracy?) that REL does

Regardless of placement in my room, the Titan exhibited a seemingly un-attenable boost in the mid-bass. Depending on placement the boost ranges from +3 to +7 in the 40-100 Hz range. The sonic result is less than appealing, given that my mains are flat which are flat to 50 and down 6dB at 40.

Even in the best placement, a flip of the phase switch produced some interesting results. The response of the Titan was to become very flat across the board with the exception of a 5dB dip at 50 and a 5dB rise at 63. Yes, you read that right ... a 10dB shift. A real roller-coaster ...

An e-mail to ACI prompted a response which suggested:

“It is possible that (because of the low end extension of your mains) the sub and the mains are "stomping" on each other. Flipping the phase switch may have put the sub out of phase with the mains which would seemingly flatten the whole system but with erratic (as you stated "roller coaster") side effects. The proper position for the phase switch is the one which gives the most bass. From there, any boom is tamed through the crossover, gain, and possible main rolling off.

I would try filtering the mains at 65 hertz and then at 85 hertz. This may smooth things out a bit.”

Despite my unwavering disdain for filters, I agreed to try them. At my request, ACI overnighted two sets of filters because the trial period on the REL was quickly coming to an end and I had only four days to finish my comparisons.

These “passive” filters go between the amp and pre-amp and are inserted immediately before the amp. I tried the 85 Hz filter first. All other things aside, even at low volumes, it was difficult to not be distracted by the obvious localization of the sub. Scratch those. In with the 65 Hz filters.

Frankly, I was expecting nothing but trouble. Instead, I walked away slightly amazed. I was hard-pressed to identify any added grain or stridency; the filters were surprisingly transparent. Moving on to fine tune the set-up, I was able to flatten out the response from 20 to 160 Hz quite nicely. The only anomaly was a persistent 5 dB bump at 63. Nothing I did, short of reducing the gain (and impacting the other frequencies, as well) would diminish this rise. Short of heroic efforts, this was a good as it was going to get in
my room.

Fair enough. Time for some serious listening. As it turned out, the best placement of the Titan in my room allowed me to put the REL in the room, as well, allowing for some rather quick comparisons when tempted to do so.

In the end, I preferred the REL.

• There was something about the Titan’s character which I could not come to grips with. It was a Jekyll and Hyde thing. I found it to produce subjectively tighter (a la Sunfire), better articulated bass (yet not as realistic), yet I could never get it to match tonally the rest of the system. It always managed to find a way to intrude into the music.

• Its ability to be articulate in the deepest bass, yet come off as “boomy” overall confounded me.

• Even after I got the frequency response to match as closely as possible, it would overwhelm the mains when things got cooking. It had a tendency to “jump out of nowhere” when it wasn’t really called for; something the REL never did.

• At the “proper” level of gain, it was simply intrusive. When the gain was reduced, you could only discern it’s presence during very loud passages; the rest of the time it was missing in action.

• Oddly, while the filters may have freed-up the mains a bit and allow them to perform with less effort, the dynamics of the system seemed constrained with them in place. As I mentioned, the passive filters did not introduce audible grain or stridency into the mains. However, the systems overall tonal balance was much more healthy when the mains were run full-range.

• The Titan delivered an exaggerated sense of weight to almost all the music; compared with the REL’s natural “support” of the music, the Titan seemed to “land on” and overwhelm it.

The biggest revelation for me is that going into this, I was sure that a sub with a Dunlavyesque Q of .6 would have to be a better match for my mains, which offer tight, very-well articulated bass to the mid 40’s. In the end, despite it’s “apparent speed” the Titan could not match the overall character of my system nearly as well as the REL, even when using the Titan’s speaker-level inputs.

The REL integrates quite naturally with the system. It does not call attention to itself. I think the best compliment one can pay a subwoofer is to not know it is there. Such a compliment came a couple of weeks ago. A friend who is familiar with the system was visiting and commented on the apparent increase in the clarity, scale and weight of several favorite recordings, but did not notice the sub. A few flips of the switch convinced him that the “box in the corner” did have something to do with what he was hearing. The REL plays its supporting role with subtlety and finesse. And it dishes out the heavy stuff when called upon to do so.


IN CLOSING —————

I can’t say enough about the effortless manner in which the REL fit into my system. I continue find myself amazed at the contributions it’s making while at the same time being so “invisible.” This unit never calls attention to itself, yet manages to help instruments and vocalists find their place in the soundstage and maintain stability (of place) and a degree of clarity that is heretofore unsurpassed in my system. The REL has been touted repeatedly in other reviews for it’s ability to seamlessly integrate with a variety of mains and “carry forward” the character of most any system it’s asked to support. Was this all sheer marketing hyperbole?

N-I-M-S. It really did the trick.


* ADDENDUM: THE MUSIC —————
Given the constant mantra of many that most music does not contain much sub-35 to 40 Hz frequencies, I was surprised at how much low-frequency content there was on numerous favorite recordings. While I selected a couple of albums for their obvious low-bass content (*) the most critically evaluated recordings included:

*Weinberger: Polka and Fugue Reference Recording cd
* Soundtrack from Titanic #8 Unable to Stay cd
Alan Parsons Project Vulture Culture lp
Oregon Ecotopia lp
Karajan Adagio cd
*Jennifer Warnes The Hunter cd
Ray Obiedo Iguana cd
Muddy Waters Folk Singer lp
Ring Soul to the Pleasure cd
Monks of Keur Moussa, Senegal A Mass and Hymns lp
Holly Cole Temptation cd
Cowoy Junkies Trinity Session lp
*Dead Can Dance Spirit Chaser cd
Deep Listening Band Ready Made Boomerang cd
Adam Makowicz The name is ... lp
Me’Shell Ndegeocello Plantation Lullabies cd
Terry Evans Puttin’ It Down cd
*Hearts of Space TAS Sampler cd

The Hearts of Space disc has oodles of low-frequency synthesized bass that submerges you in the nether-world at healthy levels of gain.

With subs in place, the recording venue of the Cowboy Junkies album revealed itself as more spacious than ever before.

The Deep Listening Band and the Muddy Waters album both revealed the most interesting aspect of the addition of a sub to the system. DLB was recorded in an underground, concrete cistern. The odd array of instruments exploit the cavern’s characteristics in some very interesting ways. The sub allows a deeper view into the cistern and the “music’ played therein. The same holds true for the sense of space in which the Muddy Waters LP was recorded.

Plantation Lullabies (“If that’s your boy friend, he wasn’t last night) highlighted the REL’s ability to pressurize the listening room and makes it’s presence known out in the street 40 feet away from the house, as well.

Ring’s “Soul to the Pleasure” features Barbara Imhof on harp, Patti Clemens’ voice and various friends injecting upright and fretless bass, slide guitars, talking drums and other percussion. The subs reminded me about how deep the harp (and marimba) actually play. They added a good deal of weight to the each instrument’s presentation.

Karajan’s Adagio has a couple of pieces that feature some interesting pairings of instruments, including the organ. While one would expect the subs to bring out the best in that instrument, it was not lost on me that Adam Makovicz’s left-hand work on the piano has never been better revealed in my system.

The Benedictine Monks of Keur Moussa, Senegal, are unique in a number of ways. Of the 24 brothers, 12 are Senegalese and the other French. They make their own instruments, including a kora with keys (as opposed to the more traditional African harp). They also write their own liturgy, mixing traditional African strains with the Gregorian tradition. Xylophones, with graduated wood resonators, whose sound is amplified by gourds of various sizes. Handmade drums, and flutes round out the instrumentation. In a
word, the album is nothing but inspired. If sounds interesting to you, it may take a bit of effort to track down their collections. I got their album about 12 years ago through the Musical Heritage Society. For information on their recordings you can contact: Monastére de Keur Moussa; P.O. Box 2459; Dakar, Senegal. The Library of Congress catalog number is 81-750214.*

Enjoy.

© Stephen Harrell, 1998

* Since I originally posted this, Dave VH was able to source this album through CD now. Of course, it's not on vinyl, but he claims it still sounds very good.;-)


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Topic - REVIEW: REL Acoustics Strata II Speakers Review by Stephen at Audio Asylum - Stephen 09:35:09 04/19/99 ( 3)