Finally! Firsthand demo of Smyth "SVS Realiser" - AVS Forum
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post #1 of 35 Old 03-23-2008, 12:59 AM - Thread Starter
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Well it only took three years, but I finally got to experience a firsthand demo of the Smyth "SVS" multi-channel virtual surround product. Having been in contact with them about the subject ever since I first read the interview with Steve Smyth in WideScreen Review (September 2004), I was this week invited to visit their relatively nearby facility for a personal demonstration of their just-about-ready-for-primetime product.

They're exhibiting at the Head-Fi show in Ft. Lauderdale this May 3-4 if anybody's interested in having their own demo, and are about to enter a small prototype production run (to see if there are any production problems). Thanks to my patience and long-time interest I've been promised "serial number 0001" of their long-awaited product!

So... after all of this waiting, was it worth it? All I can say is REMARKABLE! With initial marketing expected to target the pro audio customer, I myself can't wait to get one (even though I'm hardly a pro audio person).


First, the hardware.

As it turns out the current incarnation of the SVS box is much smaller than its original prototypes and photographs showed it, or at least it's much smaller than I imagined it would be. Obviously it's been physically redesigned from the earlier versions. It's now maybe 8" wide, about 1 1/2" tall, and perhaps 6" deep.

There's an information display panel (perhaps 3" wide) on the left-front of the SVS box, along with an array of associated small LED's to the right of the display panel. As with many multi-channel processor boxes five of the LED's are arranged around a "listening position" to represent which channels are in use or are being tested, calibrated, etc. The rest of the LED's are for other status, channel, or function indications.

On the back of the SVS box are eight balanced 1/4" TRS analog connectors typical of pro audio (and which can also be used with unbalanced connections) for discrete analog channel input from an external discrete analog channel source (where the multi-channel decoding from a digital source is also assumed to take place).

Also on the back are eight balanced 1/4" TRS analog connectors for output. In other words, more than one of these boxes can be "daisy chained", or this box can be placed in the "5.1/6.1/7.1 analog path" on the way to an analog input multi-channel preamp/amp, etc.

And finally, also on the back is a standard L/R-stereo analog output pair of RCA connectors to go to the headphone amp.

Smyth's retail product is also going to include an "entry level" Stax headphone (looks to me like the SR-202) along with an "entry level" class-A headphone amp (non-descript, may be Stax but doesn't look like Stax SRM-252II, but perfectly adequate). Even if you don't need this gear you'll get it, because the also included system-critical "head tracker" (gyro-sensing gizmo that sits atop the headphone band) works well with this headphone's plastic band (which is over the suede band that actually sits on your head).

The head-tracker faces "forward" and emits an IR signal that is picked up by a small IR receiver that is placed somewhere directly in front of you, most likely directly above or below the TV screen, computer monitor, or center speaker you're facing. The IR receiver can either stand on its own small base or a spring-clip bracket swings down so that it can be attached to the top of a flat-screen TV or computer monitor.

The lower part of the face of the IR receiver includes eight small photocell sensors arranged in a circle. On top of of the face is a horizontal row of six (or eight) small green LED's that light up to represent the left/right orientation of your head (presumably you're wearing the headphones with the head-tracker on top). If you're looking straight ahead, the center two LED's will be lit. As you turn slightly from left to right the corresponding off-center LED's illuminate to indicate your off-center angle and the other LED's turn off.

The IR receiver has a thin cord attached (maybe 10' long?) which plugs into a small "HT" jack for it on the front of the SVS box. There's also a second/alternative headphone output stereo mini-jack on the front of the SVS box. I don't know if both front and rear headphone outputs can be driven simultaneously.

Also on the front of the SVS box is what looks like a USB-port, into which the head-tracker itself can be plugged when not in use, for recharging (as there's a rechargeable battery in the gizmo).

The front of the SVS box also provides a card-reader slot, for a standard SD flash card. This card is used to store calibration data which thus "personalizes" the performance of the equipment. The RAM in the box can store up to 32 different "personalizations", which if desired can be written to or read from the SD flash card for external transportability to another SVS box.

And finally, on the front of the SVS box is an input "mini-stereo" connector jack for a crucial component of of the SVS product: the high-sensitivity binaural stereo calibration microphone pair (one for each ear, joined onto a single stereo cable). This binaural calibration microphone pair will also be part of the delivered product.

Also included in the product is a handheld remote containing buttons to completely control the SVS box, including the ability to select specific/ALL channels for listening, instantly selecting one of four different "personalizations" for A/B/C/D comparison, etc.


Now for the experience.

Only after a demonstration of how the equipment is to be used can you truly appreciate what this SVS box does. Remember, it is NOT a digital source decoder... as that is expected to occur external to the box in some piece of equipment containing a Dolby or DTS codec with discrete channel analog output. All that is fed to the SVS box is up to 8 discrete analog audio channels decoded from an originally multi-channel digital source (typically DD5.1 or DTS or any of the newer HD audio codecs). This discrete multi-channel analog input is what is then processed down by the magic software in the SVS box into 2-channel L/R stereo output intended for headphones.

Once the SVS box has been "calibrated/personalized" its output (from any source) through headphones is intended to "EXACTLY REPRODUCE the original listening environment" experience in which that exact same source would sound (down to loudness as well as tonal quality, along with 3D-sensation) when played through through true physical loudspeakers (and which were used to perform the calibration/personalization in the first place).

In fact, as amazing as it sounds I can attest to the fact that once calibrated/personalized you cannot distinguish the sound of the same physical loudspeakers which were part of the calibration process and the SVS-produced results through the Stax headphones. The same 3D-spatial front/rear/left/right cues that come from the physical speakers surrounding me in the demonstration room were precisely duplicated by the standard 2-driver L/R-stereo headphones... including when I turned my head!! Even loudness levels matched, as did tonal quality.

The "calibration/personalization" process starts off with the stereo binaural calibration microphones (each surrounded by a foam shell, just to get them to fit snugly) being placed in your ears. Then the SVS box goes through a two-part process.

First, a signal generator produces sound individually for each loudspeaker and the calibration microphones take readings as a full-frequency sweep is repeated eight times individually from each speaker in the room as you look straight ahead at the center speaker. The entire process is repeated a second time as you rotate your head to the left, looking at the left speaker, and then a third time as you rotate your head to the right looking at the right speaker. The result of this process is that the precise physical characteristics of your own personal ear canal structure are exactly quantified, as determined by the calibration microphones sitting inside your ears. Everyone's ear structure is slightly different, but the result of this "personalization" is that the SVS box now knows exactly how sound which enters your ears actually sounds... to you.

Second, the Stax headphones are now placed on your head and over the calibration microphones which are still in your ears. A different set of sound sweeps is now produced by the SVS box but this time played through the headphones. The calibration microphones now pick up that sound coming from the headphones and relay the quantification to the SVS box, which adjusts the output levels in realtime until the headphone levels exactly match what would have been the original loudspeaker levels. In other words, the headphones are "equalized" to the loudspeakers and other external auditory factors which made up this particular "listening environment", so that they are both (1) just as loud which is crucial, and (2) reproduce the 3D-characteristics of the environment.

In other words, the true purpose of the SVS box is to "duplicate exactly how you yourself hear sound, in a given listening environment"... meaning everything that went into that auditory experience such as speakers, sound reflections off of walls, floor and ceiling, the quality of the sound equipment and electronics, etc.

EVERYTHING that contributes to how you personally would hear and then describe what you heard in a given room or given listening environment, is precisely picked up by the binaural calibration microphones placed in your ears for the "personalization process" and absorbed by the SVS box and then processed into a "personalized profile" of that particular listening environment, based on how your particular ears heard things. This might just as well be described as a "quantified audiological analysis of your own personal ear canal" for that specific listening environment.

And again, I have to say it: IT WORKS! Once calibrated to my own personalization, I was able to easily take off the headphones (and tilt them down so that the IR emitter in the head-tracker tells the equipment to turn off the headphones and turn on the loudspeakers) and listen to the loudspeakers instead. Doing this A/B comparison repeatedly I swear you really cannot tell the difference. The Stax headphones, via the SVS processing, are duplicating exactly all of the tonal qualities and 3D-spatiality of the loudspeaker sound. THEY SOUND THE SAME!

Oh yes, forgot to mention that the SVS processor also has a built-in 16-band EQ controlled by the software, in order to duplicate the tonal characteristics of the loudspeaker and enviroment sound.


Ok, finally... how might this be used by an audio pro?

Well imagine a producer who listens to and mixes music in a studio, listening to recorded material through physical studio monitor loudspeakers in order to be "tweaked". Imagine now if all auditory characteristics of that precise studio listening environment AS IT IS ACTUALLY HEARD BY THAT PERSON could be "captured" digitally by an SVS box, and then put on an SD flash card and brought home where it could be placed into a second SVS box attached to headphones, where playing back that same recorded material through headphones would be AN EXACT AUDITORY DUPLICATE OF THE STUDIO LOUDSPEAKER EXPERIENCE! You wouldn't have to be in the studio in order to do the work, as the SVS box has exactly duplicated how the studio sounds... but through headphones rather than through loudspeakers.

Or, imagine taking the SVS box and calibration microphones to multiple environments (stadium, auditorium, arena, office, etc.) and creating a personalization profile for YOUR ears for THAT listening environment, and recording it. Then you can play back any source material through headphones, choosing that particular SVS profile, and relive the experience of listening in THAT listening environment... while in your bedroom!

Or... even more potentially fabulous... imagine taking an SVS setup to a high-end audio dealer or elite setup, with $200K worth of audio equipment and the world's best sounding speakers. Now you sit down and calibrate a profile for THAT remarkable sound environment, and take it home with you... a digitally reproducible analog image of exactly how that listening experience, on that equipment and in that room, sounded to you!!! After that, you can play music through headphones in your bedroom and have the sonic quality as if you were listening on that $200K never-achievable dream system with the dream loudspeakers! Of course you'll have to talk that dealer into letting you "steal the sound of his $200K system", but if you can then you're home free. $200K "home theater in a box"... for $3K.

32 memories in the box, but really an infinite number of quantified listening environment profiles on the SD flash card medium.


Anyway, I repeat: this was a REMARKABLE experience. You honestly have to hear it for yourself to believe it.

I did request one other test, to convince myself that my own personalized auditory quantification was different from somebody else's quantification (which is why shipping the product with a "standard factory-preset" set of values is worthless and meaningless). There is no such thing as "a best set of values". It's YOUR ears and how YOUR ear canal shapes and influences sound quality on its way to YOUR brain, and it's a particular listening environment (one among an infinite array of possiblities) that is being calibrated and calculated. There is no such thing as "best". Meaningless concept, with this SVS capability which simply duplicates ANY listening environment as it sounds to YOU.

So I asked that one of the other office staff go through the same calibration/personalization, which I would than be able to compare in an A/B test (using the "profile" buttons on the remote).

And, just as described to me in advance, the different auditory results were MORE THAN SUBTLE. My own "profile" sounded clear and precise, and very realistic... to me anyway, and very accurate. In contrast, the other fellow's "profile" sounded artificial and over-3D processed, moved back in my head instead of right in front of me, and very unnatural. Amazing.

Of course I was obviously attempting to listen to how sound appears to the other person based on that other person's ear canal, which is naturally not how my own ear canal is structured... which is why the "personalization" of the SVS box to my own physical ear canal is exactly that, allowing it to precisely reproduce for me how a particular listening environment sounds to me and me alone.

I'm sure that the other person would have a similar reaction if listening through my SVS profile... even when the exact same listening room environment was used for the calibration. Kind of like trying to wear someone else's eyeglasses, or using their bowling ball, or wearing their shoes (already broken-in by their feet), etc.


Final note: price point is still planned at $3K, for everything I've described above. Production is forseen for Summer, retail availability in the Fall.


Possible future hardware upgrades: HDMI 1.3a connector, to receive decoded discrete multi-channel source as PCM via HDMI rather than through 8 analog connectors.


Final comments... I plan to use my current Stax SRM-T1S headphone amp and Omega-I headphones. I also mentioned to Steve that I planned to also use my DBX 14/10 EQ in-line (between the output of the SVS box and the input of the SRM-T1S), to provide additional tonal control as I currently do with my Dolby Headphone Pioneer DIR-SE1000C setup.

He was concerned about possible phase shift resulting from the EQ processing which would of course affect the 3D-effect of the SVS box, but if the EQ were "linear" and "netural" then it could certainly could be used without ill effect.

Also, it was pointed out that the SVS box output could be RECORDED (e.g. to tape or CD) for external playback (e.g. in your car), where presumably it would produce a similar 3D-effect. I used to do that years ago with my Carver Sonic Hologram processor in the tape loop of my stereo system, when I recorded cassette tapes with this added processing. Playing back these tapes in my car sounded 3D!

Now I don't know if playing back a recording in my car which was made out of the SVS box would "only sound right to my ears" and to nobody else, or good and 3D to everybody, well I don't know. And would it again seemingly duplicate that original listening environment (or whatever SVS profile I had selected when doing the recording)? Certainly this will be an interesting experiment.
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post #2 of 35 Old 03-23-2008, 08:49 AM
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Thanks very much for the report.
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Originally Posted by DSperber View Post

And finally, also on the back is a standard L/R-stereo analog output pair of RCA connectors to go to the headphone amp.

So there is no digital output (2-channel PCM)?
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Even if you don't need this gear you'll get it

Do they let you buy one without the headphone and amp?
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First, a signal generator produces sound individually for each loudspeaker and the calibration microphones take readings as a full-frequency sweep is repeated eight times individually from each speaker in the room as you look straight ahead at the center speaker.

Is the signal generator contained within the SVS box, or is it a separate box? How does it connect to your speaker system?

Does the box allow you to pause and resume the calibration at any point, which would conceivably allow you to use a single speaker and physically move it to each location? That way, for example, you could use a single $800 speaker instead of eight $100 speakers. I suppose that you could also move a subwoofer speaker to each location, which would be equivalent to having eight subwoofers.
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So it doesn't look like there will be a stripped-down mass-market $500 version (i.e. the YSV-1) as had once been envisioned.

Are any manufacturers besides Yamaha considering SVS?
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Now I don't know if playing back a recording in my car which was made out of the SVS box would "only sound right to my ears" and to nobody else, or good and 3D to everybody, well I don't know.

Are you talking about listening to headphones while riding (but not driving) in your car, or using your car's speakers to play the recording?
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post #3 of 35 Old 03-23-2008, 07:03 PM - Thread Starter
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Quote:
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So there is no digital output (2-channel PCM)?

No. Only analog L/R-stereo output.

Also I've now been told that both the front mini-stereo output and rear L/R RCA outputs are active simultaneously. But this isn't intended for "two people" as much as just providing a connection convenience depending on your personal setup. Remember, the unit is "personalized" to your own ears so it wouldn't make sense to try and feed headphones to two separate humans at the same time.


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Do they let you buy one without the headphone and amp?

I asked the same question, and the answer was no.

It's the entry-level Stax SRS2050II Basic system, and they're just trying to ensure that (a) everything you need is in the kit, and (b) you will not be disappointed with the result, as these Stax SR-202 headphones and matching amp work well.


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Is the signal generator contained within the SVS box, or is it a separate box? How does it connect to your speaker system?

The signal generator is in the SVS box. The loudspeakers are connected to some 8-channel analog receiver, which is "downstream" from the SVS box and connected to it from the 8 analog outputs on the back of the SVS box.

I've now been told that these 8 analog outputs are not normally active at the same time as the L/R-stereo headphone outputs... that in fact they are normally "muted" by the software when the headphone outputs are active. However the box can be placed in "pass-through" mode by switch (or the remote) to bypass the headphone outputs completely.

But normally it is the head-tracker (i.e. tilt of the headphones, if off of your head) which control things and will cause the software to mute the headphones and activate the loudspeakers, or vice versa. In normal operation, with the headphones on your head, the loudspeakers (i.e. the 8 analog outputs on the back of the SVS box) are muted.

So if you did actually want to feed a second system of loudspeakers, or second SVS box, you'd use a set of Y-connectors (off of the 8 analog inputs). This would also eliminate any concerns about time-delays (and subsequent lip-sync with video) induced by signals passing THROUGH the SVS box, etc.


Quote:


Does the box allow you to pause and resume the calibration at any point, which would conceivably allow you to use a single speaker and physically move it to each location? That way, for example, you could use a single $800 speaker instead of eight $100 speakers. I suppose that you could also move a subwoofer speaker to each location, which would be equivalent to having eight subwoofers.

Didn't ask that question. It all happened quite quickly really, and I can't imagine doing what you propose. The entire 2-part calibration process I described took no more than 5 minutes.

In the demo room at Smyth, they had six speaker positions, but it really was a 5.1 setup. L-front, R-front, L-rear and R-rear were identical (speaker enclosure about 3 feet off the ground, on a stand) with a sub-woofer next to each standing loudspeaker. In front of me, below the TV (not on a stand), was a center speaker with another sub-woofer next to it on the floor. Behind me was another identical speaker/sub-woofer pod, although it was only being fed the LFE .1 channel so almost all of its output was coming from the sub-woofer.

As I described earlier, it doesn't really matter what is coming out of each speaker pod, nor how many you have (at least up to 8 are supported by the current SVS box outputs)... as many as you have constitute the "listening environment" whose characteristics will be "duplicated" by the processor. Each speaker pod will be repeatedly frequency-swept by the signal generator and sampled by the calibration microphones eight times (to lower the S/N-ratio floor in the calculated result), and the personalized profile that is produced will duplicate the loudspeaker listening experience. You're supposed to be sitting stationary during the 5-minute process, either looking straight ahead, or left or right.

I honestly can't imagine trying to do what you propose during the process, namely using a single high-quality speaker and moving it around (using your "assistant"?) while you sit stationary and repeatedly pause/resume the setup at each opportunity. Anyway I don't believe this is possible.


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Are any manufacturers besides Yamaha considering SVS?

They've not precluded licensing with anyone else, and their interaction with Yamaha is still ongoing.

But for the moment the initial product will certainly only be their's.


Quote:


Are you talking about listening to headphones while riding (but not driving) in your car, or using your car's speakers to play the recording?

Using the car's speakers to play the recording.

In other words, record the simple 2-channel analog L/R-stereo RESULTS of the SVS processor (intended for headphones, for maximum and intended 3D-effect) just like you can record any other standard 2-channel analog stereo signal to cassette tape (or CD) for playback through any 2-channel analog stereo device (boombox, iPod, personal CD audio system, or your car's stereo system).

If this works the same as my Carver Sonic Hologram recording/playback experience, then the playback of this processed signal through loudspeakers (i.e. not headphones) in an enclosed environment such as your car should produce similar "standing wave interference" and at least "simulated 3D" to some degree.

I know that with my Carver-processed cassette recordings that playing them back in my car allowed rather precise "location" of the instruments and voices, etc., in the soundstage in front of me and all around me... much like I was sitting in an "ideal listening room". It was wonderful, and far superior to just standard 2-channel L/R-stereo playback.

But the Carver processor was intended in the first place for a particular loudspeaker-based listening room for playback, where standing wave interference would be as intended. It was not intended for headphones and its unique characteristics. So I don't know (yet) if playing a recording of an SVS-processed signal through a car's loudspeaker system will be sort of like listening through "very large headphones" and similarly 3D-like and amazing or won't work at all. But it's worth a shot.

Yet to be determined.
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post #4 of 35 Old 03-23-2008, 09:32 PM
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I honestly can't imagine trying to do what you propose during the process, namely using a single high-quality speaker and moving it around (using your "assistant"?) while you sit stationary and repeatedly pause/resume the setup at each opportunity. Anyway I don't believe this is possible.

Having an assistant move the speaker would be nice, but I was thinking that you could just turn your head, and keep the speaker in the same place the entire time. What changes is the speaker's location relative to where you are facing. For example, to have a center speaker, you would face the speaker. To have a front left speaker, you would then turn your head 30 degrees to your right, so the speaker is now 30 degrees to the left of where you are facing. And so on and so forth for each speaker location. If you can manage to turn your head quickly enough between speaker locations, then I suppose you don't really need a pause/resume function.
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post #5 of 35 Old 03-24-2008, 12:06 AM - Thread Starter
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Having an assistant move the speaker would be nice, but I was thinking that you could just turn your head, and keep the speaker in the same place the entire time. What changes is the speaker's location relative to where you are facing.

And spin around completely to get the measurements on the "rear surrounds" and "rear-center"?

We did another interesting experiment, to contrast my own "personalization" results vs. that of the other fellow. Steve pointed out to me that while you could A/B compare "all channels" simultaneously and see some difference, it was much less subtle and much much more obvious if you compared only "center channel" for both humans. He explained that the whole structure of our ears and how they capture and focus sound waves is designed to be forward-facing, because that's what's most important to us. Sound that is behind us is much less important than sound that is front of us, and our physiology reflects that.

So he had me compare first my own left-rear vs. the other fellow's left-rear. And there was essentially no difference at all. Then he had me compare my own center vs. the other fellow's center. And it was night and day. Put all channels together, and it is noticeable which is mine and which is his... and I could no doubt pick them out in a blind A/B test. But compare just center channels and it is night and day, both the quality and placement (i.e. the "source" of the sound localization relative to the center of my head).

So, coming back to your thought about rotating your head and/or body relative to a single fixed speaker, just to satisfy the requirements of the multi-directional calibration process, I suppose that would work... technically speaking. But I still think you're just "gaming" the system, whereas the goal of the process is to capture the complete ambience and overall balance of the total "multi-source listening environment", including the job done by the audio system electronics and speakers for each separate channel, the reflections of sound off of walls, floor and ceiling, from each speaker and reflected angle as heard by your ears, etc.

Steve also pointed out the inherent differences with the similar but different "non-personalized" fixed-spatiality approach taken by the Dolby Headphone technology. They have a different target marketplace, and simply decided to average-out a bunch of different sets of measurements into a static "one size fits all" result. And that's why some people say "it works great" and others say "not so much".

I am very much looking forward to getting my hands on an SVS box (perhaps within two months). My DBX EQ has two sets of inputs, so I will be able to do an A/B comparison between the SVS result and the Pioneer DIR-SE1000C Dolby Headphone result for the very same multi-channel digital source (e.g. "Dexter" on SHOHD, or an audience show like "American Idol", or an "Eagles Live" D-VHS recording from NBC-HD which had terrific sound, or their "Hell Freezes Over" DVD which is reference-quality audio).

Of course I still need to decide what kind of receiver or DAC to get to be my multi-channel analog source.
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post #6 of 35 Old 03-24-2008, 08:57 AM
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And spin around completely to get the measurements on the "rear surrounds" and "rear-center"?

Yes. Exactly.

Of course, it would be easier with just two speakers. When you face forward, they would be in the usual front left and right locations. But when you turn around, they would become the surround left and right locations. Since you are presumably sitting in the sweet spot, you might not bother to calibrate for a center speaker.
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post #7 of 35 Old 03-25-2008, 04:17 AM
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This sounds amazing, thanks for the updates on the technology.

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Steve also pointed out the inherent differences with the similar but different "non-personalized" fixed-spatiality approach taken by the Dolby Headphone technology. They have a different target marketplace, and simply decided to average-out a bunch of different sets of measurements into a static "one size fits all" result. And that's why some people say "it works great" and others say "not so much".

I've not heard either, but I have experienced a few binaural recordings over my Koss ESP-950 electrostats. It's a quite different thing, I know, but these recordings also use a "one size fits all" approach in that the dummy head used has ears that can only represent an average ear. Listeners also experience varying degrees of immersion due to this. While I find at times that these recordings represent the most fantastic immersion I've yet experienced from a recording, other times (more often) I only get imaging behind my head. I would like to try making my own recordings some day with a pair of in-ear binaural mics and one of the new breed of portable, high-quality 24/96 PCM recorders (they're very cheap these days). Such recordings would also be measuring/storing my own ear's particulars as the sound passes through to the mic.
My point is that taking the listener's own ears into account is crucial to tricking the brain with real spatial cues.

Jack Gilvey
SVS Customer Service

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post #8 of 35 Old 03-25-2008, 04:33 AM
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Quote:
Originally Posted by DSperber View Post

Using the car's speakers to play the recording.

In other words, record the simple 2-channel analog L/R-stereo RESULTS of the SVS processor (intended for headphones, for maximum and intended 3D-effect) just like you can record any other standard 2-channel analog stereo signal to cassette tape (or CD) for playback through any 2-channel analog stereo device (boombox, iPod, personal CD audio system, or your car's stereo system).

If this works the same as my Carver Sonic Hologram recording/playback experience, then the playback of this processed signal through loudspeakers (i.e. not headphones) in an enclosed environment such as your car should produce similar "standing wave interference" and at least "simulated 3D" to some degree.

I know that with my Carver-processed cassette recordings that playing them back in my car allowed rather precise "location" of the instruments and voices, etc., in the soundstage in front of me and all around me... much like I was sitting in an "ideal listening room". It was wonderful, and far superior to just standard 2-channel L/R-stereo playback.

But the Carver processor was intended in the first place for a particular loudspeaker-based listening room for playback, where standing wave interference would be as intended. It was not intended for headphones and its unique characteristics. So I don't know (yet) if playing a recording of an SVS-processed signal through a car's loudspeaker system will be sort of like listening through "very large headphones" and similarly 3D-like and amazing or won't work at all. But it's worth a shot.

I can't see any way for that to work. SVS separately recreates what happens in each of your ears and then sends separate signals to each ear. With speakers your right ear will hear everything sent to the left hand speaker and vice versa.

Sucks that they won't sell the device without bundled headphones.

Also sucks that there's no onboard DD or DTS decoding - adds a completely pointless Digital->Analog->Digital conversion in the middle of the signal chain which can only hurt sound quality.

Also sucks that Yamaha cancelled the YSV-1. I was looking forward to that; okay, it would have been a cheap device but it was rumoured to have a digital output, which probably would have sounded quite good feeding an external DAC.

And the price of the Smyth device sucks too.

They ought to do an all-digital version with no analogue inputs or outputs, I bet that would be cheaper....
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And the price of the Smyth device sucks too.

Until the price of SVS comes way down, I'll probably stick with my DH processor (a JVC SU-DH1 that costs under $100).

This $3K SVS product reminds me of the TheaterPhones HSM6240, which was an early DH processor targeted for professional use and was priced at $1K.
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I can't see any way for that to work. SVS separately recreates what happens in each of your ears and then sends separate signals to each ear. With speakers your right ear will hear everything sent to the left hand speaker and vice versa.

You're probably correct. If I were to listen to the recording through headphones or ear buds that would be a different story.

In contrast, the Carver idea was dependent on loudspeakers and standing waves in the room. So playing the recording through the car's sound system is very similar... and works.


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Sucks that they won't sell the device without bundled headphones.

Well if you look at the retail price for the entry-level Stax system that they're including it's $750. I believe they're just planning on passing it along at their cost, which would be less than retail. So I don't think it's really bumping up the total product cost that much.


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Also sucks that there's no onboard DD or DTS decoding - adds a completely pointless Digital->Analog->Digital conversion in the middle of the signal chain which can only hurt sound quality.

What about the final digital->analog conversion to feed the headphone outputs? I'm not entirely sure that everything in the box isn't in the analog domain, to avoid all of this and provide another justification for why their inputs are discrete multi-channel analog. Hard to believe they'd have all of those conversions in the equipment.


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And the price of the Smyth device sucks too.

Actually this hasn't changed for a few years even though they're including the headphone system, calibration mikes, remote, head-tracker and IR receiver, and the box itself.


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They ought to do an all-digital version with no analogue inputs or outputs, I bet that would be cheaper....

Again, I'm not sure this isn't an all-analog product as even the discussion of HDMI was still based on decoded PCM being delivered (that would be just one D->A conversion for the input).
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I would like to try making my own recordings some day with a pair of in-ear binaural mics and one of the new breed of portable, high-quality 24/96 PCM recorders (they're very cheap these days). Such recordings would also be measuring/storing my own ear's particulars as the sound passes through to the mic.
My point is that taking the listener's own ears into account is crucial to tricking the brain with real spatial cues.

Last year I invested in A/D equipment and high quality binaural microphones just like you're describing... although I have yet to actually make such a recording.

I have a Sony TCD-D100 DAT recorder.
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Well if you look at the retail price for the entry-level Stax system that they're including it's $750. I believe they're just planning on passing it along at their cost, which would be less than retail. So I don't think it's really bumping up the total product cost that much.

I suppose you could just sell the headphone and/or amp to recoup some of the cost.
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Also, it was pointed out that the SVS box output could be RECORDED (e.g. to tape or CD) for external playback (e.g. in your car), where presumably it would produce a similar 3D-effect.

Would they let you make a recording during your personal demo? That way you could relive it afterwards.
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You're probably correct. If I were to listen to the recording through headphones or ear buds that would be a different story.

Of course the callibration parameters will depend on the headphones; so, to get the maximum benefit, you would need to callibrate the box using the exact pair of headphones you plan to listen with, then record using that profile. (This may put a bit of a dent in the "borrow someone else's home cinema for 10 minutes" idea - you'd have to borrow it again every time you buy new 'phones or a new headphone amp, otherwise the callibration won't be accurate any more).

Driving wearing headphones is very dangerous, btw.

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What about the final digital->analog conversion to feed the headphone outputs?

What about it? Obviously one would have to use an external DAC, but something like a Benchmark DAC-1 would give you superb results for relatively little outlay. One can skimp money on a purely digital device without doing much damage to the output quality; you can't skimp on the DACs and the output stage. (And it's nice to be able to upgrade that independently of the digital source).

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I'm not entirely sure that everything in the box isn't in the analog domain, to avoid all of this and provide another justification for why their inputs are discrete multi-channel analog.

I find that extremely difficult to believe. Much more likely they just didn't want to pay the licensing fees for a DD or DTS decoder and are cutting corners.

It may also be partly a reflection of the way they expect the device to be used: for practical purposes it's useless unless you already own a properly set-up home cinema speaker system, because without one you can't callibrate it. It is therefore designed primarily to do for home cinema speaker setups what conventional stereo 'phones do for a stereo speaker system: act as a substitute when you don't want to disturb people. If that's the only context it is used in, then money can be saved by not including decoding ability, because most users will already have it in the same room.
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Last year I invested in A/D equipment and high quality binaural microphones just like you're describing... although I have yet to actually make such a recording.

I have a Sony TCD-D100 DAT recorder.

Nice stuff. I wasn't thinking quite that ambitiously recorder-wise, maybe a little portable from Zoom, etc. Those mics had come up in a google search I did, love to hear about them if you do decide to record something.

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Nice stuff. I wasn't thinking quite that ambitiously recorder-wise, maybe a little portable from Zoom, etc. Those mics had come up in a google search I did, love to hear about them if you do decide to record something.

I went with the 4060 "high-end binaural" model, which has the higher sensitivity intended for quieter recording environments.

The story is that if you make a stereo recording fed from these binaural mikes, with the two mikes clipped on to either temple of your eyeglasses say (and pointing forward), that playback through headphones will be astonishingly 3D-like and true-to-life... very much like your ears and brain (and the mikes) heard things originally.

Someday I'll actually get to do it.
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The signal generator is in the SVS box. The loudspeakers are connected to some 8-channel analog receiver, which is "downstream" from the SVS box and connected to it from the 8 analog outputs on the back of the SVS box.

I think this approach might not work for some receivers. Even if the receiver has 8-channel analog inputs, the receiver might merely amplify them to drive the speakers. That is, the receiver might not perform any of its usual processing for bass management, equalization, speaker distances, etc. If that's the case, the receiver can probably apply processing to its 2-channel analog inputs, so you could at least do a proper calibration for stereo.
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I think this approach might not work for some receivers. Even if the receiver has 8-channel analog inputs, the receiver might merely amplify them to drive the speakers. That is, the receiver might not perform any of its usual processing for bass management, equalization, speaker distances, etc.

That's exactly what you want.

Remember that the SVS box is simulating what the power amp and speakers would normally do with the processor output: bass management happens before the signal reaches the SVS box. So the receiver will calculate bass management, and decide to send signal X to a satellite speaker and signal Y to the subwoofer. The SVS box picks up signals X and Y and calculates how the combination of those two channels (if actually sent to the satellite and sub) would sound at the ear, then plays that same sound over the headphones.

During the callibration stage you want to completely isolate the sound of the satellite and the sound of the subwoofer and figure out how to deal with them separately.

Presumably, in normal use, the SVS box would sit in between the processor and the power amp (in a system where those are separate boxes) so I would guess its output is suitable for feeding directly into the power amp; that means there won't be a problem if the processor only has 5.1 analogue inputs and not 7.1.

People who have a single-box receiver with only 5.1 inputs but 7.1 speaker outputs are screwed though.

(That may be another reason why they don't include digital decoding circuitry, actually: if they did then the SVS box would have to do its own bass management, which is not a simple bit of processing).
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That's exactly what you want.

No, not necessarily.
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Remember that the SVS box is simulating what the power amp and speakers would normally do with the processor output: bass management happens before the signal reaches the SVS box.

During the calibration process, the SVS box is generating the frequency sweep signals. In other words, these signals originate from the SVS box. They travel from the SVS box to the 8-channel analog input of the receiver (not the other way). Before they are amplified by the receiver, you might want the receiver to perform bass management. However, the receiver might not be able to perform bass management on its 8-channel analog input (even if it can perform bass management on its other inputs), in which case the low-frequency response of your speaker system would be degraded, so the SVS box would be trying to match the degraded sound.
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Presumably, in normal use, the SVS box would sit in between the processor and the power amp (in a system where those are separate boxes)

If you are using separates (as opposed to just using a receiver), I'm aware that you could put the SVS box between the processor and the power amp, and thus avoid this issue (as long as you always use that particular processor to feed signals to the SVS box after calibration).

I suppose it boils down to this:
Was your bass management already performed downstream of the SVS box during calibration?
Or will your bass management always be performed upstream of the SVS box after calibration?
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During the calibration process, the SVS box is generating the frequency sweep signals. In other words, these signals originate from the SVS box. They travel from the SVS box to the 8-channel analog input of the receiver (not the other way). Before they are amplified by the receiver, you might want the receiver to perform bass management.

No, you don't.

If you callibrate it with bass management on its output then the only way to make it sound right in normal usage would be to apply bass management downstream of the SVS box when it's in use. How do you propose to do that?

You need to prevent bass management from happening during the callibration process, otherwise it won't work correctly.

Remember, the SVS box simply emulates speakers.
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If you callibrate it with bass management on its output then the only way to make it sound right in normal usage would be to apply bass management downstream of the SVS box when it's in use.

No. If you choose to perform bass management during calibration, then you should not perform that same bass management during normal usage, because those crossovers were already taken into account during calibration. Otherwise, you would be applying those crossovers twice, in effect, so they would be too steep.

In addition, it does not makes sense to apply any crossovers downstream of the SVS box during normal usage. The only things that are downstream of the SVS box during normal usage are your headphones and maybe a headphones amp. If you want to apply any crossovers during normal usage, they should be upstream of the SVS box.
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Remember, the SVS box simply emulates speakers.

The SVS box emulates speakers, including the effect of any crossovers within those speakers. The calibration process takes into account all crossovers that are in the calibration chain. Once those crossovers have been taken into account during calibration, you should not apply them again during normal usage. The only crossovers that should be applied during normal usage are the ones that were not taken into account during calibration.
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Erik, everything you've just said is explaining why you must avoid bass management during callibration.

Think about the way the system works if the SVS box is not in the chain at all. The player sends a digital signal to the processor. The processor decodes it and does bass management. It then sends signals to the power amp. What the SVS box does is emulate the power amp and the speakers: you feed the same already-bass-managed signal to either system.

During callibration the SVS box feeds a signal directly to the power amp, and measures how the sound at your ears varies, depending on the signal fed to the power-amp. If you stick an extra layer of bass management in between the SVS box and the power amp during callibration then the SVS box will end up trying to emulate not just the power amp and the speakers but the bass management process as well; and during actual usage you will have bass management applied twice, once by the processor and once (badly) by the SVS box.
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Erik, everything you've just said is explaining why you must avoid bass management during callibration.

What I'm trying to point out is that there are two ways.

1. Avoid BM during calibration and then apply BM during normal usage, or

2. Apply BM during calibration but then don't apply BM again during normal usage.

I'm saying that you can choose to do it either way. I'm not sure why you are insisting that #1 is the only correct way.

In case it helps, I have attached a diagram that shows the 2nd way.
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post #24 of 35 Old 03-27-2008, 07:43 AM
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Originally Posted by Erik Garci View Post

What I'm trying to point out is that there are two ways.

1. Avoid BM during calibration and then apply BM during normal usage, or

2. Apply BM during calibration but then don't apply BM again during normal usage.

Well, okay.

I'm not sure that approach 2 makes much sense in practice: it depends on whether the maths processing inside the SVS box is sophisticated enough to be able to emulate bass management. It's not just a question of doing the original cross-over calculation, it's modelling the acoustic effect of a single input signal being split across two geographically separate speakers, without the box knowing whether it is dealing with one speaker or two. This strikes me as potentially much more complex than its normal mode of operation.

Basically the SVS box is designed to emulate a power amp and speakers; emulating a bass-management-capable processor at the same time is not (AFAIK) part of what it is designed to do.

However, the reason I started grumbling about this was your original statement:
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I think this approach might not work for some receivers. Even if the receiver has 8-channel analog inputs, the receiver might merely amplify them to drive the speakers. That is, the receiver might not perform any of its usual processing for bass management, equalization, speaker distances, etc. If that's the case, the receiver can probably apply processing to its 2-channel analog inputs, so you could at least do a proper calibration for stereo.

The fact that a receiver doesn't apply bass management to its analogue inputs is not a problem: it simply puts you definitely in scenario 1 rather than scenario 2. I'm still not certain why you think the receiver not doing bass management on its analogue inputs during callibration is a problem. So long as the receiver is acting as your source in normal usage it won't be.
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It's not just a question of doing the original cross-over calculation, it's modelling the acoustic effect of a single input signal being split across two geographically separate speakers

One of those two speakers is the subwoofer, which people have difficulty locating anyway, so maybe the SVS box puts more effort into modelling the location of the other speaker than modelling the location of the subwoofer.
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So long as the receiver is acting as your source in normal usage it won't be.

If I'm understanding correctly, you use the 8-channel analog "pre-amp" outputs of your receiver (if it has them) to feed into the SVS box during normal usage. Your source devices are connected to the receiver's digital inputs, so the receiver is applying BM to them. Now it makes sense to me. So there's no problem.

Here's a new diagram.
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Just a followup...

I believe we'll see the "appearance" of a representative from Smyth to this discussion once an actual product actually becomes available for sale, which shouldn't be too much longer. Then we'll be able to get our questions answered directly, and should also be able to provide worthwhile feedback to them.

In the meantime, I did get some answers to my questions.

(1) There is an A/D conversion upon entry to the box. From there it is entirely digital processing, with a final D/A conversion at the end... to the headphone outputs.

(2) Logically, the SVS box is trying to emulate loudspeakers, and they want it to 'sit' between the audio source and the loudspeaker amplifier.

(3) The initial target marketplace is the pro audio user, not the home audiophile. Such users aren't as concerned with DD/DTS decoding in the box, as home users would be.

Professionals aren't interested in decoding these formats - - they want to monitor the loudspeaker signals. For a consumer unit decoding DD/DTS internally would certainly be very useful. So this is something they're considering for consumers.

(4) Having digital input (e.g. optical 8ch over PCM) is of interest to pro users since often they are working on digital audio editing workstations anyway, and have multichannel AD and DA converters. This would also reduce the cost of the Realiser, and so again they're certainly considering it along with a 2-channel digital output (for feeding to an exteranl DAC).

Of course leaving decoding of "modern codecs" (including future codecs) to an external source device allows the SVS box to be "future proof". So either decoded PCM or decoded analog certainly seems like a good design idea.

(5) The discussion about bass management was quite accurate. In fact they do have bass management features built into the SVS box, primarily to allow pro users to evaluate a consumer speaker set-up (virtually of course), rather than to replace the normal bass management of a good AV receiver.

SVS wants to be treated like loudspeakers. Loudspeakers know nothing about bass management. All the bass management should occur upstream of the SVS box. However, on occassion this may not be possible, particularly for pro users - hence the necessary inclusion of some BM.
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DSperber, are you implying that Smyth intends to release a "consumer" version of the product farther down the line?

If they want to make a future-proof device they could always use a two-box model: have a pure-digital front-end which does nothing except decode digital input signals into multiple PCM streams and then a second box which has no A/D conversion capability but accepts multiple PCM digital inputs, does SVS calculations, and produces stereo output (either analogue or digital). If new formats come along all you then have to do is replace the front-end box, which is probably comparatively cheap because of the complete absence of analogue components.

Some people might even just buy the second box and drive it straight from a BluRay player.
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Originally Posted by Erik Garci View Post

One of those two speakers is the subwoofer, which people have difficulty locating anyway, so maybe the SVS box puts more effort into modelling the location of the other speaker than modelling the location of the subwoofer.

That presupposes that the SVS box knows it is talking to two different speakers. But it doesn't: it would simply be plugged into a single analogue input on the processor and would have no idea that the processor was doing bass management.

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If I'm understanding correctly, you use the 8-channel analog "pre-amp" outputs of your receiver (if it has them) to feed into the SVS box during normal usage. Your source devices are connected to the receiver's digital inputs, so the receiver is applying BM to them. Now it makes sense to me. So there's no problem.

I think you are understanding correctly.
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That presupposes that the SVS box knows it is talking to two different speakers. But it doesn't: it would simply be plugged into a single analogue input on the processor and would have no idea that the processor was doing bass management.

I don't think that the SVS box needs to know how many speakers you use for each channel. For example, if you use several speakers along the left wall for the Left Surround channel, I think the SVS box will just try to match overall sound produced by the LS speakers into the two microphones. I don't think that the SVS box will try to extract the sound of each individual LS speaker from the overall sound of the LS speakers. The SVS box leaves it up to your ears and brain to figure out where the sound is coming from and how many speakers are producing it.
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post #30 of 35 Old 03-28-2008, 07:25 AM
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I don't think that the SVS box needs to know how many speakers you use for each channel.

Probably not. I was simply objecting to this statement:

Quote:


so maybe the SVS box puts more effort into modelling the location of the other speaker than modelling the location of the subwoofer.

In order to "put more effort into modelling the location of the other speaker than... the subwoofer" it would have to know that it is dealing with an "other speaker and a subwoofer".
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