Secrets SSP (Surround Sound Processor) Benchmark Specifications

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  • Aussie Geoff
    Super Senior Member
    • Oct 2003
    • 1914

    Secrets SSP (Surround Sound Processor) Benchmark Specifications

    Hi,

    Thanks to Glenn, Club Rotel members were made aware of an interesting article by Brian Florian in the “Secrets of Home Theatre and High Fidelity” Web site titled “The Secrets SSP (Surround Sound Processor) Benchmark Specifications”.

    The link to the article is http://www.hometheaterhifi.com/volum...y-11-2003.html

    The intent of the article is to suggest a set of “Benchmarks Specifications” that the authors believe should apply to all Home Theater Processors regardless of price. This benchmark is intended to be a follow on to the web sites successful DVD Benchmark that has evolved over the years and been used as a reference point for the kind of features high end players should have. In a forthcoming (December) article the authors intent to assess currently available processors against this benchmark with a view to maintaining a list of the degree of compliance (as the site does for DVD players).

    Based on both my following the progress of the original DVD Benchmark and a broad knowledge of the current HT Processor market – my sense is that this benchmark (like the original) will be influential. Initially there will be a surprisingly low level of full compliance (almost none) but over time there will be an increasing adoption by the market matched by an evolving benchmark standard. IE Don’t worry about the number of areas of “non compliance” right now, most other HT processors have similar types of issues and it will take time for the market and the benchmark to align

    I am going to use the benchmark article in two ways:
    1. To undertake our own assessment of the 1098, checking against, what is already their, what is on our wish-list and what is new.
    2. To separately contact the authors and suggest an upgrade to their benchmark for several key features that are missing (and with some of us 1098 owners enjoy).


    I look forward to:
    • Your feedback as to whether I have it right or not (there are a couple of guesses in the list!)
    • Comments on the suggestions I have made for potential inclusions in the 1098 wish list.
    • Any other feedback you may have.


    The quotes below are all extracts from the above article and are © Copyright Secrets of Home Theater & High Fidelity.


    Time Alignment

    Global AV Delay (a.k.a. "Lip Sync" Delay)
    While this has always been an issue for people with certain high end video processors, more and more of the current progressive scan TVs, and all of the Plasmas, LCDs etc, are digitally processing the video signal and in most cases delaying it to one extent or another. As such, an SSP's ability to delay the audio program by a complimentary amount is becoming a must-have. We pass a unit here if it offers a global audio delay for purpose of synching the audio program with a video program delayed by a video processor. Minimum acceptable range is 0-60ms. 0-100ms or more is preferred. While a minimum acceptable adjustment increment is 15ms, which corresponds to 1 video field in NTSC, 1ms is greatly preferred. While we'd like to see this setting be unique for each input, at this time we will not fault a design for having only one global setting.
    Complies 100% - Has 500 ms delay

    Speaker Delay
    Speakers Delay, or Time Alignment is critical to getting the best performance from any multi-channel setup. We have an article on why that is so. Setting it correctly can be daunting, especially for someone new to the Home Theater hobby. We've seen some of the most expensive (and undeservedly praised) SSPs get this completely wrong. The preferred method for setting speaker delay is by inputting the distance from the prime seat to each speaker. Adjustment increments should be no more than 0.5 feet (which corresponds to 0.5ms). Each speaker in the 5.1 or 7.1 array, including the subwoofer, should be set separately to pass this test. Borderline pass will be given to units which at least keep the following groups separate: Front L/R, C, Surr L/R, and Rear L/R (it is unacceptable if Surround and Rear are lumped together, or if the subwoofer is not time aligned at all). If a unit uses "raw" ms delay for time alignment, it must automatically and transparently add 15ms to the surrounds for all matrix decode processes (fail if unit requires user to set total delay for each surround mode). Units which offer an "automatic" delay (and level) setup function with a microphone get a particular nod of approval, but these must offer a way to override and set it manually. I've had a couple manufacturers complain to me about this, saying that their microphone system is accurate enough that they don't need a manual option. They shut up when I asked them what an owner is supposed to do if they lose or damage their microphone.
    Complies 90% - Has fully separately adjustable delays for all channels. However doesn’t have the adjustment increments of “no more than 0.5 feet”.
    Known V2.0 wish list enhancement to get the 0.5ft or less delay setting.

    Volume

    Muting
    Some people like "Mute" to be a total silence. Others like it to be an attenuation. With most SSPs using digitally controlled analog volume, offering the choice should be a matter of course. The test unit will pass if it offers a choice of attenuation (range of choice should be -10 to -50dB with 10dB increments) or full mute. Mute must be a dedicated button on the remote.
    Complies 30% - Mute has dedicated button and full mute but not variable options.
    Potential Wish list item.

    Power On Volume / Max Volume
    These are "safety" items. It's too easy for the volume to be ramped up without due regard for where it's at. We pass the unit if it offers the option of a pre-set power-on volume. In the case of multi-zone units, power-on volume should be independent for each zone. The Unit also must offer a max volume setting or other suitable limiter, preferable if it is password protected (so the kids can't change it and blow up your speakers).
    Complies 100%

    Input Level Trim
    The unit must offer separate input level trim for each input.
    Not available
    Current Wish-list 2.0 item.

    Volume Scale and Speaker Calibration
    The Volume scale should be industry standard relative. That is, "0dB" corresponding to reference level and descending from there in relative dB, down to (-) infinity. For the volume scale to be properly calibrated, each speaker, including front left/right, must have its own calibration setting.
    Complies 50% - Each speaker has it’s own calibration setting, however volume is not relative to reference.
    Potential Wish list item.

    Headphones
    Headphones should be independent of the main zone and have their own volume control. For multi-zone units, the headphone jack must be able to monitor any zone.
    Not available. No headphone jack.

    Dolby Digital

    DRC (Dynamic Range Control)
    The unit must offer a minimum of two levels of Dynamic Range Control in addition to none or off. For a full pass, the DRC setting must be adjustable from the remote control and not be buried deep within setup menus (if it takes more than three button presses to get to it, that's too many). We also want to see a small indicator on the front panel when DRC is set to anything but "off".
    Complies 100%

    Dolby Digital EX
    Full pass will be given to THX Surround EX or Dolby Digital EX licensed products which use two speakers and/or line outputs for the center surround (in other words "6.1" is not acceptable). All 7.1 SSPs must respond to the EX flag in the bit stream. If not a Dolby/THX licensee (i.e.: "EX Clone") we test the unit for a Stereo 3 matrix decoder and pass the unit only if it uses one (if a clone uses a standard matrix decoder, any out of phase material in the two surround channels will be lost).
    Dialog Normalisation
    Complies 100% - Has full Dolby Digital EX flag processing

    The unit must assert Dialog Normalization and NOT provide any means for the user to defeat or bypass it. We want SSPs to have some means of indicating the current dialnorm value, ideally something persistent.
    Lock-On Time
    The unit should not impose any noticeable delay in locking on to a new AC-3 bitstream.
    Complies 100% - Rapid Lock on (compared to Krell etc!)

    640kbps AC-3
    The unit must be able to play 640kbps Dolby Digital bit streams (note: 640kbps AC-3 is not actually in the DVD-Video spec but all consumer decoders should be capable of decoding it).
    Complies 100% - Rapid Lock on (compare to Krell etc!)

    Pro Logic

    Surr Encode Flag Reading
    The unit should read the "Surround Encoded" flag in two-channel AC-3 bit streams and set Pro Logic/Stereo playback appropriately, and the user must be able to override.
    Not available (as far as I am aware) for 2 channel AC-3 DD – Setting must be done manually.
    Potential Wish list item.

    Non-mandatory Music Features
    Panorama, Width, and Dimension must be adjustable by the user to pass this criterion.
    Complies 100% - All parameters user adjustable

    Bass Management

    Crossover Frequency
    The crossover frequency of the unit’s bass management should be selectable from at least 40 to 120Hz in at least 10Hz increments. We also want to see a choice of (A) 4th order low pass/2nd high pass (for use with THX and other dedicated satellite speakers) ,or (B) 4th order low pass/4th order high pass (for use with "full range" speakers or those not expressly designed to be high passed).
    While its certainly possible and acceptable for units to offer more complex bass management options, such as a different choice for each speaker, we don't require it. In our article Miscellaneous Ramblings on Subwoofer Crossover Frequencies we make a pretty good case for setting speaker as "small" (regardless of actual physical size) and selecting a crossover frequency at or near 80Hz. Again, to be clear, its not that we fault more extensive flexibility here, its that we don't require it for our definition of correct and acceptable bass management.
    Complies 80% - Full variable cross over frequency by speaker. However THX and non THX slope choice is not available (offers non THX)
    Potential Wish list item.

    LFE Trim
    Units must provide an independent LFE trim adjustment for Dolby Digital, DTS, and (in the future) MLP.
    Complies 100% - Separately controllable for all surround modes

    DVD Audio

    Bass Management/Time Alignment
    Test units must provide an option to digitize analog 5.1 inputs so that they inherit the bass management and time alignment of the SSP. Until a digital link is standardized, this is the only way to get the most out of 5.1 music.
    Not Supported (as far as I can tell!)
    Potential Wish list item.

    THX

    THX Select, Ultra, and Ultra2 Certification
    Don't worry, we would not dare suggest that all units must be THX Certified to meet Secrets Benchmark. Yet because certification requires that a manufacturer design into the product electrical specs which (from what we've been able to weasel out of people on the inside) meets or exceeds anything we've thought about putting on paper, we like to see it covered. Such qualities can and most certainly do exist in non-THX SSPs but with THX Select now appearing on AV Receivers as inexpensive as $700 SRP, the argument that the THX logo ads appreciable cost is no longer holding true.
    Does not comply.
    Known V2.0 wish list enhancement.

    THX Re-Equalisation
    All THX units must provide the ability to select THX Re-Equalization independent of THX Home Cinema, THX Surround EX, and THX Ultra2 Cinema. This choice should not be reset when changing modes or cycling power.
    Does not comply.
    Known V2.0 wish list enhancement.

    Audio Customization

    Parametric Subwoofer Eq
    Units must provide a 1-3 band parametric Eq for the subwoofer output. We will accept designs which only allow a cut (and not any boost).
    Does not comply.
    Known V2.0 wish list enhancement.

    Surround Mode Pre-Set
    Units must provide a set of surround mode preferences for each signal type, and these presets must be unique to each input. Borderline pass if it is a global set.
    Complies 100% - fully controllable.

    Multiple Surround Management
    In the case of 7.1 units, a choice must be provided of where to route the surrounds of 5.1, i.e., to the Surrounds, Rears, or Both. This choice must apply to all sources, including the 5.1 analogue input(s).
    Complies 100% - fully controllable.

    Academy Mono Filter
    The test unit passes if it offers industry standard Academy filter option on mono playback. Borderline pass if the unit offers "clone" HF roll-off for academy mono soundtracks.
    Does not comply.
    Potential Wish list item.

    Down-mix
    All 5.1 AC-3, DTS, and 5.1 analogue inputs must be down-mixed for headphone, rec path, or stereo zone outputs. The LFE channel should be discarded from the down-mix.
    Complies 90% - Down mix available from all sources except the 7.1 Analogue inputs

    Miscellaneous

    Front Panel Dim
    Because SSPs and AV Receivers are frequently in the front of the rooms, often very close to the TV, we feel it is of great importance that the front panel and corresponding lights be dimmable so as not to distract from the movie. Units must provide the option to dim the front panel, including all lights/LEDs, for a pass here. Preferably two illumination levels should be available, one high intensity during interaction and one low intensity during inactivity. The lowest setting available should be barely visible in a pitch black room.
    Complies 50% - TFT can be turned off, but not other LEDs etc.
    Potential Wish list item.

    Settings Storage
    Units must store (retain) all parameters (speaker level, distance, volume preferences etc.) in memory during power outage.
    Complies 100% - All parameters saved, even for extended power off periods.

    Notes on User Interface

    While we would be delighted to see manufacturers solicit our input on SSP User Interface, at this time we are not going to spec a utopian definition of one because quite frankly, people's opinions differ here. We will however come down hard on an SSP when something is obviously wrong or universally difficult to work with.
    ANY item which might be toyed with during normal use, such as the DRC settings, or Pro Logic II music parameters, must be readily available from the remote, and when changed during playback, must be changed in that input's setup and be retained as such. In addition, if at any point we feel we need to hook up a TV/monitor to get a handle on things, that's no good. Everything should be "doable" with the front panel display.
    We will publish a separate subset to this document which defines what we want to see in terms of IR code sets in an SSP.
    Complies 100% - All settings easily available from the remote.

    Several Logical Menus
    As a general outline, we'd like to see several logical menus:
    A) Hardware setup, which would include speaker selection, level calibration, time alignment, etc.
    B) Preferences, which would include volume control options, surround mode parameters, front panel dimming, etc.
    C) Input setup, unique to each input, which would set input specific items such as level trim and surround mode presets.
    Broadly complies – number of menus are different but have very logical structure.

    Remote Control Access
    ANY item which might be toyed with during normal use, such as the DRC settings, or Pro Logic II music parameters, must be readily available from the remote, and when changed during playback, must be changed in that input's setup and be retained as such. In addition, if at any point we feel we need to hook up a TV/monitor to get a handle on things, that's no good. Everything should be "doable" with the front panel display.
    We will publish a separate subset to this document which defines what we want to see in terms of IR code sets in an SSP.
    Complies – Everything can be done with the TFT display

    Remote Control Ergonomics
    Like the overall UI, we are not going to dictate one perfect remote design, because there is no such thing. This is why products like the Pronto have flourished: You take a blank touch screen and turn it into YOUR ideal remote. We do however want to see certain remote control features as mentioned above. That includes quick, easy access to frequently used functions, and an overall adherence to good ergonomic design. The remote should have backlighting for use in dark home theaters, buttons appropriately positioned, and above all different in shape and size from one another, according to their function.
    Complies – Backlighting, buttons etc. (But a Pronto is still way better!)

    Enjoy! I look forward to your postings and Emails

    Geoff Costello
  • Andrew Pratt
    Moderator Emeritus
    • Aug 2000
    • 16507

    #2
    Good work Geoff:T It looks like our 1098's meet their requirements for the most part so it should be interesting to see how it stacks up against the other pretenders




    Comment

    • Tim_D
      Member
      • Nov 2003
      • 30

      #3
      Thanks for doing this Geoff! The results will be interesting. Would there be any value in adding the 1066 to this list?

      Tim

      Comment

      • Glenn
        Senior Member
        • Jun 2003
        • 109

        #4
        Geoff

        Thanks for all the time and effort you've put into this comparative analysis! I really am looking forward to all of the Benchmark testing, and of course especially of the Rotel products. Likely they will test only the 1098, but perhaps the 1066/1055 will be reviewed as well.

        I also believe the Benchmark Specifications as suggested by Secret's, makes an excellent case for the suggestions (specifically for the 1098 ) made by our own Club Rotel members. As you've summarized, we've commented and addressed many of the same features as Secret's has deemed to be important. Looks like we're all on the same wavelength.

        Hopefully Rotel finds the upcoming Benchmark tests useful in continuing to develop and upgrade their (great) products.

        Comment

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