Onix/Rocket RS 750 Signature Edition Speakers, Part II...

Discussion in 'Home Cinema Speakers' started by elcid, Sep 27, 2004.

  1. elcid


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    The Onix/Rocket RS 750 Signature Edition Speakers, Part II

    My Own Opinions, True Enough…

    What follows are my initial impressions of the Onix/Rocket RS 750 Signature Edition transducing system. However, be advised that although my “review” of the speakers in question is purely an exercise in sheer empirical subjectivism as no objective data—i.e., measurements, frequency response curve charts, etc.--are provided (that forte is the domain of real, more qualified speaker reviewers like Craig Chase, Ed Muller, Don Keele, Joe D’Appolito, Tom Nousaine, Peter Eczel, et al), I still hope that you, the genteel reader, manage to find the contents of this essay of some practical value…

    The Nuts And Bolts…

    I’ve been running the 750s through their paces practically every day ever since their arrival two weeks ago, so have a pretty good idea of what I believe to be is their particular sonic signature. To aid me in that task I used a fairly wide variety of sound sources, including music and film soundtracks, both in analog and digital sound formats.

    The associated equipment used to audition the 750s consists of a Pioneer SVX-49TX Elite receiver, Samsung SIR-T165 OTA high-definition TV receiver (for monitoring Dolby and DTS digital sound from Mitsubishi 2000U and JVC 40000U D-VHS tape decks—these devices are connected via FireWire interfacing—their digital bitstreams being spewed by the Samsung STB unit itself via a Toslink optical interface, thus feeding film soundtracks from both D-Theater and D-VHS high-definition video tapes into the Pioneer Elite receiver), Mobitsu 880 and Sony DVP-S7000 DVD players used for DVD and CD playback respectively, as well as a Pioneer LDS-504 laserdisc player for Dolby AC-3 digital and analog sound playback (too bad this unit isn’t equipped with a PCM output jack as it would have enabled uncompressed digital sound from laserdiscs so encoded to be heard. Oh, well…I’ll try one of the Pioneer LDS-2 Elite LD players for that purpose later on). This set up comprise what I call the “small” HT system.

    A variety of interconnecting cables were used to interface the above listed components, some of which included a pair of 80s vintage eight foot lengths of Kimber 8 speaker cable (one of the few reminders left around here from my former association with high-end audio-itis, the Linn Sondek LP-12 turntable/Eminent Technology II air bearing, linear tracking tonearm and a sundry of MM, MC pickups, head-amp, and Dr. Sao Win strain-gauge cartridge system being the others).
    A pair of SVS B4-Plus subbass systems were also incorporated into the mix, the “Black Beauty” twins being temporarily powered by an early 80s vintage Soundcraftsmen, 250 watts R.M.S. per channel @ 8-ohms power amplifier. No EQ was applied to these infrabass behemoths.

    The 750s were placed nearby the display device and equipment rack of the secondary home theater system, spaced about 8-9 feet apart (couldn’t place the right side closer because the magnetic fields produced by all of those bass/midrange and high frequency drivers causes extreme amounts of highly visible impurities on the picture tube of the Sony XBR-800 television set. Don’t really know whether these speakers are shielded or not) and “toed-in,” while still creating an aurally believable “phantom” image, so that separation distance worked just fine.
    Wishing to avoid introducing yet another unknown variable into the mix, I opted to conduct the listening sessions with their speaker grills on, thus my impressions of the 750s reflects this fact.
    By the way, because of the living room’s furniture “arrangement” I was forced to place the B4-Plus subwoofers midway each wall opposite of each other (the right side being next to one of the 750s), thus corner loading proved to be an unattainable proposition.
    Still, bass output was such that hardly needed to be corner-loaded in this particular instance since playing back at fairly high sound pressure levels the whole house was shaking quite a bit with low bass sources (steady state test signals mostly), so it wasn’t a drawback at all. The B4-Plus subbass system’s potential hasn’t been fully realized!

    The listening venue is nothing more than my living room where the oft mentioned small home theater system resides. The living room’s hardwood and contiguous dinning room’s tiled floors are uncarpeted, and no attempts to tame bass, midrange, and high frequency response anomalies that are bound to exist were made, thus is not the best acoustical venue for evaluating audio components.
    Once all necessary work that needs to be accomplished on the “big” dedicated home theater room and its sound system’s revamping is completed, comparative listening sessions between the 750s and the current main L&R speakers will begin. However, that’s a story best left for another time…

    Getting Down and Boogey!...

    Music selection ran the gamut; I listened from baroque to cathedral organ pieces, as well as symphonic and operatic works (including the famous Tchaikovsky’s 1812 Overture finale on Telarc’s label); from big band classics to excerpts from film musicals; from Dixieland and be-bop, to contemporary jazz (“fusion” included, but no Kenny G!); from blue grass to modern C&W; from ethnic music from around the world, to rock-n-roll, disco and just about everything else in between.

    Film soundtrack wise, selection also ran the gamut, thus I tried certain selections from film soundtracks such as Open Range (gun shots, rain, and thunder storms), Finding Nemo (need I say why?), Black Hawk Down (you know why!), U-571 and Das Boot (any guesses why?), Mel Gibson’s The Patriot (real black powder cannon volleys recorded in real open air venues), My Fair Lady (to check directional stereo tracking and both male and female singing voices), The Wind And The Lion (another directional stereo tracking source), El Cid (to listen to a “dated” 6-track magnetic soundtrack stems from 70mm elements via Dolby AC-3 which was sourced from laserdisc), Auntie Mame (mono track even on the taped high definition version that recently played at the HDnet Movies satellite channel, used to assess the quality of female and male speaking voices), as well as movies like Titan AE, Toy Story 2, et al.

    I also availed use of recordings I made myself years ago with an analog 10 ½” open reel tape deck and a pair of PZM microphones (featuring our drum sets, a local student from the Redlands University Music Department playing a Bach piece transcripted for the cello, as well as percussion instruments such as claves, maracas, triangle, timbales, cowbells, and tunable “roto-toms” that were used in an attempt to “test” and determine midrange impulsive transient attack response, which is a darn good indicator of sonic accuracy as far as I am concerned since I believe that midband performance is loudspeakers design engineering’s most crucial and critical element for accurate sound reproduction.
    Get the midrange right and sonic flaws and deficiencies such as a tipped up or droopy high frequency response, weak bass sound output or over ripeness, for instance, are factors that can be dealt with, forgiven, and made up for!).

    I See A Light At The End Of The Tunnel...Do You Too???...

    One of the most notable sonic aspects of the 750s I noticed right off the bat is how super-wide the soundstage appeared to be as the soundfield not only seemed to possess tremendous breadth and depth, but also defy the very physical boundaries of the enclosures themselves as it was often heard well past the edges of the fornt panels!
    Overall, soundstaging seems to be literally suspended in mid air as if a gigantic canvas magically appeared in front of the listener! Amazing, simply amazing…
    I attribute this sonic asset to be directly related to the narrow front panels and ultra-deep, somewhat oval-shaped enclosures in addition to the rather dimensionally small bass/midrange drivers…all great contributors to the net sonic results of what actually turns out to be excellent midband performance, something I hinted at in previous postings.

    Push comes to shove and if I were to directly compare the two loudspeaker systems right now, I would venture to say that the RS 750 Signature Edition produce a seemingly wider soundfield than the old workhorse 4-way, full range prototype Ryan Acoustics MCL-5 main L&R transducers, but to what degree it is something that remains to be determined at a later date…

    As an aside, I must point out what for me turns out to be a slight sonic weakness…
    You see, like the vast majority of dynamic type speaker designs that employ single high frequency drivers, the 750s need to be heard with their tweeters placed at ear level otherwise vertical imaging will suffer to some degree because a credible sense of vertical height isn’t quite developed. Thus I had to sort of lie down on my couch in order for my ears to be close to tweeter level.
    Anyway, I know Rocket has speaker “risers” available for both the 750s and 550s that apparently elevates them some 10”-12” (already ordered a pair for mine).
    The speaker risers undoubtedly help with imaging height, but ultimate coupling of the bass drivers to the floor plane below (one of Roy Allison’s dictum; the other was corner loading) is bound to be compromised somewhat.
    In any event, giving up a certain amount of low bass reproduction capability is an inconsequential matter for me as I am a firm believer of augmenting the nether bass region by the addition of subbass systems anyway, so am OK with that, although this route might not be acceptable for users who prefer listening to the 750s full range.
    Anyway, I only have this to say regarding this particular issue: you ought to hear the 750s coupled to something like the recently acquired SVS B4-Plus “Black Beauty” subwoofer twins; overall performance is truly awe inspiring! But am getting ahead of myself…

    Gordon Holt, the founding father of “high-end” audio, used to say back when he headed the Stereophile journal all by himself and before his mind became polluted by a certain audiophile belief system, that nobody would actually like to listen to speaker systems that measured absolutely flat throughout the audio band because such speakers would wind up sounding extremely bright and piercing, sounding neither natural nor neutral (he suggested that a gradual high frequency rolloff to be a preferable alternative to absolute flatness). Don’t really know about that since I have never heard speakers that measured perfectly flat (have any of you?) anywhere within the audible human hearing range, so perhaps is academic.

    At any rate, another notable 750s’ sonic characteristic also noticed from the very beginning is just how natural and neutral the high frequency range actually sounds!
    That sonic region sounds to me oh, so “sweet,” silky smooth, extremely “open” and non-fatiguing, with nary a trace of bothersome grittiness.
    As far as I am concerned, these speakers produce a high frequency performance that closely resembles real life as it doesn’t call undue attention to itself by being overly bright, grainy, gritty, brash, glaring, piercing, tiring, and downright obnoxious. The 750’s high frequency performance is truly exemplary…nay, it is a colossal achievement!

    Be forewarned that driving the speakers too hard does produce a certain degree of high frequency distortion (perhaps as a consequence of amplifier clipping?), but in my case that only occurred when I played back source materials over “reference levels” (the Rat Shack sound meter kept on pegging over full scale during each brief “testing” period at such sound pressure levels, so had to cut the experiment really short), something that shouldn’t be done for hearing health’s sake in any case. However, the high frequency drivers didn’t seem to suffer permanent damage, which is something that makes me very happy as I don’t have to worry about replacing them so soon!
    In the final analysis, I believe these tweeters are robust and though enough to withstand the occasional case of sonic “abuse” that invariably is bound to happen from time to time, yet I still strongly recommend the application or use of common sense by keeping playback at sane, safe levels.
    Yet I have to wonder if AV123 speaker design engineers ever managed to blow up, er…damage tweeters under extraneous tests conditions? Umm…

    As I mentioned above, I believe midrange performance to be the most critical and crucial aspects of sound reproduction when it comes to designing speaker systems, for if it fails to be aurally perceived as being reasonably accurate in mimicking real life then all bets are off. So how accurate are the 750s? Well, let’s explore this area together, shall we?...

    In terms of frequency domain performance, midrange is impressively open and super smooth, which in conjunction with their beautifully pure, stainless, and peerless high frequency performance creates the sonic impression of being absolutely seamless…of sounding extremely well integrated and coherent in tonal balance in addition to possessing tremendous breadth and depth, thus also being highly responsible for the creation of the dimensionally immense soundstage produced by these speakers.
    Imaging can be heard with pinpoint accuracy too, which is simply fabulous (it is an asset that is highly coveted by those who proclaim to be “high-end” audiophiles, so that ought to make them hysterically happy! Bless their little piping hearts…) as each individual entity contained within sound sources, be they musical, soundtrack special effects, etc., are easily detected by the ear.

    In terms of time domain performance, things seem to roll along just fine, excepting couple of areas where I detect other slight sonic weaknesses.
    To wit…there seems to be an ultimate lack of sheer musical “weight” (the realm of much larger transducers, such as large panel, horn-loaded mid and upper bass as well as high frequency systems, or speaker designs that utilize either much larger or multiple drivers to cover and address this critical frequency region, one where these type transducers are king and rule the roost) of the sort that could even become sonically overwhelming (once a person listens to sound systems comprised of several 18” driver-based subwoofers, 15” driver-based midbass and large horn-loaded high frequency systems being driven by plenty of amplifying power all around acoustical venues, for example, will never forget just how “weighty” music and other sound sources appear as the sensation is as physically felt as much as it is heard due to the sheer massive output capability of such systems! Smaller bass/midrange drivers cannot accomplish the production of such high sound pressure level output feats; thus the 5” bass/midrange drivers utilized by Rocket for this purpose just can’t compete against such gargantuan transducing systems… being that there simply is no replacement for displacement! It’s a matter of physics, really…).

    I also detected a very slight, but still noticeable, dulling of sharp transients.
    For instance, the initial impulse “attack” of instruments such snare drum rim shots, timbales, claves, “bells” from cymbals, and cowbells seem to lose some of their unique “bite” and sharply intense sonic penetrating nature, while the tail end “decay” is shortened to an audible degree; these musical instruments are not being reproduced with 100% accuracy in my humble opinion.
    However, other transient impulsive sources such as the breaking of glass panes and bottles, all sort of metallic clanks and clinks, gunshot reports, and even softly stroked symphony orchestra triangles are sounds that emerge seemingly unscathed from the fray, a sure indication of excellent midband performance.

    At any rate, let me make it perfectly clear that I was a drummer and percussionist (as well as a bassist wannabe), so my hearing is extremely sensitive to such sharp impulsive sounds and thus am able to immediately zero-in and detect that sort of sonic flaws no matter how slight the magnitude may be.
    However, I reckon this issue might not be as important nor critically crucial to other owners for no matter what sonic flaws may exist for me still the 750s proved to be truly superb sounding loudspeakers in their own right and, at their current pricing point, represents one of the best deals in all audiodom extant; it is one hell of a bargain!

    Folks, don’t allow the reporting of these slight sonic performance flaws deter you from purchasing the 750s if that is what you have in mind all along and, if you already own them, believe that you must now replace them with something else for no speakers I know of are sonically perfect--not Wilson…or Revel…or B&W…or Paradigm…or systems from Infinity, Dynaudio, Definitive Technology, Swan, Triad, Totem, M&K, KEF, Genelec, Magneplanar, PSB, Snell, etcetera, etcetera, etcetera—by any stretch of the imagination, regardless of price…and neither are the 750s…

    As for the 750’s low end…I found their bass performance to be exemplary spite of the obvious limitations imposed by the use of small drivers which limit achieving extreme high output levels, thus no one should expect them to dig way down into the nether infrasonic bass region nor do it with the sort of authority that either much larger speaker systems or dedicated subwoofers are capable of.
    However, am sure there will be those who will find their rather fulfilling bass more than satisfying, which is fine with me if that’s their wont.
    Be that as it may, I think what bass they reproduce to be tactile, coherent in terms of sounding seamlessly integrated with the rest of their assigned audio band—overall tonal balance is exceptionally neutral from top to bottom!--while producing enough sonic “weight” to be aurally satisfying for the most part…only lacking the ultimate in low end extension and sheer sound pressure level output capabilities.

    Oh, yes…even though I agonized somewhat over the matter of calibrating the two systems to the nth degree, I still found that integrating the 750s with subwoofers to be a rather easy task so long as care is taken to properly set levels between the two systems, something that I strongly recommend because in overall terms these speakers are then transformed into a truly magnificent sounding full range transducing set up…and that’s far, far more than I can say of many other loudspeakers!

    This is my personal take on the RS 750 Signature Edition transducers. You are free to disagree with any part or the entire “review” if you so desire, of course…

    The end…

    _______________ _______________ _______________ ________

    News Flash!!!...

    While attempting to finish this essay (no easy task for me as I type one word per minute, or so it seems!) the Rocket speaker raisers I ordered for my 750s arrived and were subsequently installed (I wound up eschewing the use of either machined brass spikes or rubber “bumps” because of rather serious instability that occur even on solid, level surfaces such hardwood floors—the 750s become too wobbly thus are apt to tip to one side or the other on account of being somewhat top heavy as well as having narrow footprint characteristics—so please consider which way to go in your own particular situation).

    Folks, the sonic differences these raisers make in terms of vertical plane imaging are substantial enough to merit serious attention if you already own or are contemplating buying either the 750 or 550 systems because in most cases listeners can now sit on suitable facilities and be at tweeter level, a highly desirable factor. Try ‘em…you’ll like ‘em!...


    "...hi, my name is Frank...and am an SVS bassaholic..."
  2. Ronm1


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    Nicely done! I'll add that the risers should be strongly considered.
  3. elcid


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    Thank you, Sir! :)

    Yes, I strongly recommend the addition of the risers because of the definite sonic changes that occur with vertical imaging when one sits with one's ears placed at tweeter level...


    "...hi, my name is Frank...and am an SVS bassaholic..."

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