Smyth Research Realiser A16
Feb 20, 2017 at 12:09 PM Post #586 of 15,986
  Are there any headphones in the $800-1600 range that produce bass similar to a subwoofer?  The whole purpose of me buying this is to get the full surround experience without waking my wife in the morning rumbling the walls!

The closest experience for me has been with an LCD-2 (pre-Fazor). When watching movies through it (non-Smyth of course), the bass has that visceral impact you expect with subs, in a way that let's say equalizing a HD800 cannot reproduce. I did listen to the Z1R at the NY Canjam, and it was great through the sony headamp, however without back to back comparisons (and choice of tracks), I can't tell how it would compare, even though it has the potential to move a lot of air and capitalize on a semi-closed design.
 
Feb 20, 2017 at 4:33 PM Post #587 of 15,986
Do any of the Stax series have a good amount of deep bass?    I hope everyone knows Im talking about deep bass and not mid bass :)
How about HiFiMan series?
 
Would like to research some specific models.  Im not sure if I want to jump into these $1800-2200 levels..just a little too steep.  I was really hoping around $800-1200 and Im really looking for that WOW factor.  Ive got to wonder though... If Im using 100% for movies, will the A16 give me 90% of the wow factor and my return on the headphones may not be worth it?  I just dont know what I dont know.
 
Feb 20, 2017 at 10:56 PM Post #588 of 15,986
The sanest solution in this regard is a thing called the Subpac.  I own one, it looks like a pad or cushion you put on the back of your chair.  I connect it by using a splitter out of my headphone amp with one leg to the phones, and the second leg to the Subpac.  
 
With this, when a low note is played (and I mean deep bass and sub bass) you feel it.  I think it does a creditable job of recreating the experience of deep bass, provided your phones can deliver the actual notes to your ears.
 
Speaking of that, there are some on this thread who are maintaining the HD 800 can't do the deep bass.  I could not disagree more vehemently.  I use my 800 with Sonarworks EQ and subpac and get subterranean, precisely defined bass.  Gobs of it.  Sounds like an ultra high end system with large subs.
 
In as much as Smyth has a state of the art eq process for any phone it uses, they could not have chosen a better phone than the original Sennheiser HD 800 to recommend with the new A16 Realizer.
 
Feb 21, 2017 at 3:02 AM Post #589 of 15,986
The Sony MDR Z7 easily handles bass to 20hz or so , so is the AT ATH M50[x] both are under $500 both are closed back. The Sony will leak a little more sound. I will use the Sony when my A16 arrives.
 
Feb 21, 2017 at 3:56 AM Post #590 of 15,986
Im not sure what you mean "you manage output on the player" and 

You don't need UHD disc/player for Atmos bitstream output.


 


I never buy discs.  I always stream movies.  I believe VUDU and the rest of the services need to "see" the EDID for a 4K device in order to turn on the UHD option in the selection menu for a movie.

 

...
Sorry, I use discs (disc player) only ... And I can inform you that there are 1080p Blu-ray discs with Dolby Atmos or DTS:X or Auro 3D audio tracks. Maybe there is something similar in the streaming world too?
 
Feb 22, 2017 at 9:24 AM Post #591 of 15,986
Here is something I dont understand.  What is the difference between me going to lets say AIX studios in LA and doing a custom PRIR and me using someone elses PRIR from AIX if they have the same headphones and amp?  
 
In other words, during setup, am I giving feedback to the setup process that tells the setup that my inner ear/hearing is different than someone else?
 
Feb 22, 2017 at 9:40 AM Post #592 of 15,986
  Here is something I dont understand.  What is the difference between me going to lets say AIX studios in LA and doing a custom PRIR and me using someone elses PRIR from AIX if they have the same headphones and amp?  
 
In other words, during setup, am I giving feedback to the setup process that tells the setup that my inner ear/hearing is different than someone else?


little microphones go in your ear canal when you make a calibration for a place and a headphone. so that the sound changes from your outer ear, your head and all body are included in the speaker sound calibration.
you could be lucky and find a PRIR from someone with the same head and body as yourself (or close enough), and get a well working result. but you don't necessarily have the most average head(I know I don't
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), and variations from head to head can amount to many db in signature and several ms in delays. that's the reason why this system exists, otherwise we'd be fine with average models if individual variations were always small.
it's more efforts for much better results.
 
Feb 22, 2017 at 10:06 AM Post #593 of 15,986
to give a small and very partial example, here are the frequency responses from real people measured from an in ear microphone on the same side of the head with sound coming from 90°(so each line is a different person). it's extracted from full HRTF profiles. I didn't pick the most different ones, I just picked a few randomly within tens of people in an available catalog. don't mind the shape of the signature, only the variations from people to people:

as you can see there are of course many common parts, but also some variations that can be rather significant. and when we measure with a common headphone, we do get good information but only for sound coming from 90° angle like on this graph. we don't know what we'll need for 30 or 60degrees in front, or for a vertical angle with real speakers.
so just having the same calibration done on the same headphone model isn't enough to extrapolate the rest(sadly).
and of course if someone has a smaller head, the delays between left and right ear will be shorter than for me and my big head full of water.
redface.gif

in the end even if rather small, differences add up and may rob us from that realistic feeling we all desire. so unless we get lucky with a guy who has a head like ours, the only sure solution is to measure ourselves in the place we want to "map".
 
Feb 22, 2017 at 10:29 AM Post #594 of 15,986
When you first do the setup, is there a baseline you setup (HPEQ)  and then a PRIR is done or is everything done at one time?
Im guessing everything is done at one time.  So I could not have my baseline setup and then borrow someone elses PRIR?
 
If I cant get to one of these studios, I am basically going out to the market and trying to find someone else that went to an AIX Studios (or wherever) and keep trying different PRIRs people have posted and hope that something is close. That would be my best option?
 
 Maybe the market would look like this:
 
Studio: AIX in LA
Headphone: STAX 009 or other
Smyth Unit: A16 or A8
Amp: XYZ or none
DAC: XYX or none
Date:
Head measurement: 18" from ear to ear as measured from side to top to side (or around back)
Torso: seat to ear: 52 inches
 
Feb 22, 2017 at 10:47 AM Post #595 of 15,986
Also, does anyone have a list of studios and locations and possibly what type of studio? The Dolby Atmos theaters I have heard in Indianapolis or Ohio, have not been impressive..massive environments with very little pin point sounds and elements. i have never been fooled. Meanwhile, I have a 7.1 home theater that is pretty good but its not Atmos enabled, I never put the 4 speakers overhead. If I actually go somewhere I would want a 7.4 or more Atmos.
 
Feb 22, 2017 at 3:30 PM Post #596 of 15,986
the only sure solution is to measure ourselves in the place we want to "map".


Thank you for posting that explanation.
Suppose you have your own HRTF measured with two stereo speakers in a low reverberation room (anechoic) and you set the Realiser to not add cross-talk at convolved output.
Do you think the elevation cues - filtered by the binaural head and torso microphone transfer function - only change the listener perception of elevation of a recorded point source (in other words, the listener understand that the source is above or under 0 degree, but the listener doesn't realize the true/original elevation of the recorded point source) or completely ruin the elevation perception (the listener do not hear the source as it were above or under 0 degrees elevation)?
Now suppose you have a HRTF measured with an sphere arrangement of sixteen speakers (eight at 0 elevation, 4 at +45 degrees and four at -45 degrees) in a low reverberation room (anechoic) and set the Realiser A16 to decode ambisonics b-format to a third order convolved output. Does this second arrangement improve the listener elevation perception compared to the first arrangement?
If you think the second arrangement is worst than the first arrangement, how many channels the second arrangement would need in order to achieve the perception performance of the first arrangement?
In other words, do you believe the playback of binaural stereo recordings with head tracking and personalized dynamic convolution without the addition of crosstalk has the same performance than playback of 16 channel ambisonics output with the same head tracking and personalized dynamic convolution playback? 
My criterion would be the number of errors a listener has comparing the the elevation he believes a point-source (a person speech for instance) is and the true/original n elevation positions the source was recorded.
I would like to know your opinion.
 
Feb 22, 2017 at 4:04 PM Post #597 of 15,986
Also, does anyone have a list of studios and locations and possibly what type of studio? The Dolby Atmos theaters I have heard in Indianapolis or Ohio, have not been impressive..massive environments with very little pin point sounds and elements. i have never been fooled. Meanwhile, I have a 7.1 home theater that is pretty good but its not Atmos enabled, I never put the 4 speakers overhead. If I actually go somewhere I would want a 7.4 or more Atmos.

 
A while back I started a studio list in the Guide section of the old A8 product page. There is a table in the Realiser Measurement Locations section of the Guide here. Everyone on Head-Fi is welcomed to update the information as needed.
 
Feb 22, 2017 at 6:42 PM Post #598 of 15,986
  When you first do the setup, is there a baseline you setup (HPEQ)  and then a PRIR is done or is everything done at one time?
Im guessing everything is done at one time.  So I could not have my baseline setup and then borrow someone elses PRIR?
 
If I cant get to one of these studios, I am basically going out to the market and trying to find someone else that went to an AIX Studios (or wherever) and keep trying different PRIRs people have posted and hope that something is close. That would be my best option?
 
 Maybe the market would look like this:
 
Studio: AIX in LA
Headphone: STAX 009 or other
Smyth Unit: A16 or A8
Amp: XYZ or none
DAC: XYX or none
Date:
Head measurement: 18" from ear to ear as measured from side to top to side (or around back)
Torso: seat to ear: 52 inches

with some luck, yes you could probably end up with something really close or at least really enjoyable. that's a genetic lottery at this point and the average guy is the obvious winner as more people are like him.
I've tried to make my own lowfi stuff using other people's HRTF(unrelated to the Realiser) just for some fancy crossfeed, so I limited my search to getting a convincing image from other people's impulses that would work ok, to convolve with so called "true stereo" convolution. my best result is far from realistic, but it's also a massive improvement for me over preset crossfeeds like the Meier one. so we can fail to find the perfect stuff, but still get something cool.
from my own trials, and I have no idea if it's solid advice or not (could be accidental correlation), I have found that the measures from people with the same head circumference or diameter from ear to ear, have consistently felt better than HRTF from people with a significantly smaller head. so the head size might be a way to reduce the search. then again many people know a lot more than I do on those subjects and would be better to confirm or dismiss that correlation I've noticed.
 
the only sure solution is to measure ourselves in the place we want to "map".


Thank you for posting that explanation.
Suppose you have your own HRTF measured with two stereo speakers in a low reverberation room (anechoic) and you set the Realiser to not add cross-talk at convolved output.
Do you think the elevation cues - filtered by the binaural head and torso microphone transfer function - only change the listener perception of elevation of a recorded point source (in other words, the listener understand that the source is above or under 0 degree, but the listener doesn't realize the true/original elevation of the recorded point source) or completely ruin the elevation perception (the listener do not hear the source as it were above or under 0 degrees elevation)?
Now suppose you have a HRTF measured with an sphere arrangement of sixteen speakers (eight at 0 elevation, 4 at +45 degrees and four at -45 degrees) in a low reverberation room (anechoic) and set the Realiser A16 to decode ambisonics b-format to a third order convolved output. Does this second arrangement improve the listener elevation perception compared to the first arrangement?
If you think the second arrangement is worst than the first arrangement, how many channels the second arrangement would need in order to achieve the perception performance of the first arrangement?
In other words, do you believe the playback of binaural stereo recordings with head tracking and personalized dynamic convolution without the addition of crosstalk has the same performance than playback of 16 channel ambisonics output with the same head tracking and personalized dynamic convolution playback? 
My criterion would be the number of errors a listener has comparing the the elevation he believes a point-source (a person speech for instance) is and the true/original n elevation positions the source was recorded.
I would like to know your opinion.

opinion is really the best I can do as I'm so very unsure about a lot of things. when you say to not add crosstalk, you mean the crossfeed mixing in the convolution to place the speakers at 30degrees(or wherever it is they're placed)? or do you mean some specific method or filter to try and turn speakers in binaural ready stuff(I vaguely remember something like that exists but I don't remember what it is or does)? in any case I guess it's so that you'll rely on the binaural record to provide position cues (aside from head tracking) instead of the realiser. I'm sorry I haven't had the chance to play around a lot with a realiser, I've tried an A8 once real fast and that's it.
 
ambisonic if I remember, works as an object based sound source, with 3D positions and a virtual microphone charged to simulate the sound that should get into each speaker. I remember I thought it was great when I first heard of it because it allowed in theory for whatever speaker configuration we liked, but I'm very unclear as to the calibration method(how we "tell" the DSP where the speakers are in the room or maybe their respective signatures?).
if that can be done well, it should work great for elevation cues. as the model is 3D so it theoretically doesn't need compensation, and the speakers in the room or our head are calibrated by the Realiser. I imagine the result must be real cool. I never tried so I'm talking from what I've read and think I understand(which is usually not much ^_^).
 
now binaural. the cool thing about binaural is obviously that it's how our ears work. the problem I have is how do you get to implement binaural with the Realiser? do they provide a method(like we place the speaker at 90degree and disable the channel mixing in convolution?  the binaural album counts on 2 sound sources at 90° on our head, not on 30° stereo speakers.
also if the record already has the HRTF impact of the dummy head(if one was used while recording), there is a problem as we end up with our HRTF and the dummy's in the same signal.  if the record is simply done with 2 mics separated by an average head distance then I guess it would be better.  the difference in distance between the mics and our ear would make the sound source closer or farther away I guess, but not by much. and the head tracking being based on the Realiser with speakers, it's fine as long as the original position has been calibrated as desired. now elevation(your actual question
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) is a mystery to me in that scenario. when calibrating the A16 do we look down and up to get elevation cues if in a stereo configuration, or is it all done from a DSP model? when extra speakers are really elevated, just left and right is enough to "get them" where they are, but with stereo speakers, isn't the calibration limited to looking at each speaker one at a time?(I didn't get to try the A16 so I'm a real noob about that and don't know what changed).
 
my gut feelings tell me that 2 channels as long as all was thought for such system, can be just as good or even better than multichannels. but that's the problem, almost nothing is done for binaural use and when it is, it's usually with no efforts to be used on a custom profile.
 
did I just write rubbish unrelated to what you said, or was that the gist of the question somehow by accident
biggrin.gif
?
 
Feb 22, 2017 at 7:44 PM Post #599 of 15,986
There's a lot of work to do in this field.  Currently. the measurement is an analog process.  A person wears a set of binaural microphones in the ear canal, a signal is played over a stereo system in a room, heard by the phones, and then something happens in a black box to create a filter which enables a equalized headphone to match the sound the microphones "heard" in the ears.  
 
Currently, no modeling seems to be out there to systematically measure the respective transfer functions of the room, the playback system, and the individual doing the listening.  If such modeling were available it would be possible to create three discrete filters for each transfer function which would simplify things greatly and enable this simulation to be something other than the expensive, small volume, bespoke kind of process it currently is.
 
And needless to say this refinement should be possible b/c the entire recreation of digital sound is a mathematical process.  The convolution filters Smyth is creating are mathematical programming instructions altering the mathematical data file the music player is passing to a DAC.  There is no reason why this has to be done in one fell swoop rather than as three discrete steps. And there is no reason why each transfer function can't be indepenently ascertained and modeled either.
 
Feb 22, 2017 at 7:45 PM Post #600 of 15,986
(...)
1. from my own trials, and I have no idea if it's solid advice or not (could be accidental correlation), I have found that the measures from people with the same head circumference or diameter from ear to ear, have consistently felt better (...)

2. when you say to not add crosstalk, you mean the crossfeed mixing in the convolution to place the speakers at 30degrees(or wherever it is they're placed)? or do you mean some specific method or filter to try and turn speakers in binaural ready stuff(I vaguely remember something like that exists but I don't remember what it is or does)?
(...)

3. ambisonic (...) how we "tell" the DSP where the speakers are in the room or maybe their respective signatures?
(...)

4. how do you get to implement binaural with the Realiser?
do they provide a method(like we place the speaker at 90 degree and disable the channel mixing in convolution?  the binaural album counts on 2 sound sources at 90° on our head, not on 30° stereo speakers.

5. also if the record already has the HRTF impact of the dummy head (if one was used while recording), there is a problem as we end up with our HRTF and the dummy's in the same signal. 

6. if the record is simply done with 2 mics separated by an average head distance then I guess it would be better.  the difference in distance between the mics and our ear would make the sound source closer or farther away I guess, but not by much.
(....)

7. when calibrating the A16 do we look down and up to get elevation cues if in a stereo configuration, or is it all done from a DSP model?

when extra speakers are really elevated, just left and right is enough to "get them" where they are, but with stereo speakers, isn't the calibration limited to looking at each speaker one at a time?

8. my gut feelings tell me that 2 channels as long as all was thought for such system, can be just as good or even better than multichannels. but that's the problem, almost nothing is done for binaural use and when it is, it's usually with no efforts to be used on a custom profile.

9. did I just write rubbish unrelated to what you said, or was that the gist of the question somehow by accident :D ?


1. If two heads with the same diameter result in more and less the same ITD (correlation between head diameter and distance between the ear drums), do you think that pinna format are more and less the same and then there is also a direct correlation between head diameter and pinna size so that ILD are similar? Do you think reflections from the torso also change the ILD and can contribute to make the ILD from these two individuals with same head diameter a little different?

2. I was referring to this:

There are a number of methods for generating 3D soundfields from loudspeakers. The three most promising are 1) Ambisonics, 2) Wave Field Synthesis and 3) Binaural Audio through Two Loudspeakers (BA2L). The first two methods rely on using a large number of microphones/recording channels for recording, and a large number of loudspeakers for playback, and are thus incompatible with existing stereo recordings. The third method, BA2L, relies on only two recorded channels and two loudspeakers only, and is compatible with the vast majority of existing stereo recordings (recorded with or without a dummy head).
(...)
The playback of a raw binaural signal through two loudspeakers results in a significant degradation of the integrity of the binaural cues transmitted to the listener ears because of the crosstalk that exists between the loudspeakers and the contralateral ears. Such unintended crosstalk, which obviously does not exist in playback with headphones, requires cancellation or effective reduction if binaural audio is to be successfully implemented through loudspeakers.
https://www.princeton.edu/3D3A/BACCH_intro.html


3. Good question. I don't know. I believe you set azimuth and elevation in the decoding algorithm.

4. AFAIK there is no directive of two speakers layout for measuring a PRIR with the specific aim of binaural dummy heads recordings such as Chesky does. Since our pinna is angled and facing forward I do not see any problem using stereo speakers in triangle layouts with 90 or 110 degrees or even side by side dipoles as Dr. Choueiri uses to improve the efficiency of his algorithm.

5. That's my fundamental doubt and the reason I asked your opinion. :) I guess the HRTF of a Kemar manikin ou a Neumann KU100 during recording adds to/with the PRIR applied at the playback leading to deviations (mire wave interference). Ideally, if one could not only capture such microphone HRTF but also our own HRTF in a anechoic chamber, the algorithm could compensate for such interference by knowing the the microphone used in the recording (metadata could contain such info). Also ideally BRIR could be captured by studios with such standard microphones to make BRIR to PRiR exchange personalization more precise. But in practice anechoic rooms are rare. :)

6. Since I guess most of the elevation cues are imprinted by the size and shape of the pinna, I also guess that XY (90), ORTF (110), Jecklin disk and other microphones arrangements, though retaining a good amount of horizontal ILD and ITD cues, could lead to errors in elevation perception.

7. Since a limited number of speakers are measured, there is horizontal and vertical interpolation done by the algorithm. That's the beauty of it and something that makes the Realiser A16 comparable to the efforts of Dr. Choueiri and not some other generic room impulse amplitude filter.

8. That's what Dr. Choueiri claims and something I am eager to discover.

9. It was a pleasure reading your opinion.
 

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