[jgazal]

I bought the Crowson Tactile Transducers directly from Crowson Tech.

Crowson Technology - Home Theater Tactile Motion Actuators - Beyond Bass Shakers

I have a Crowson 300B amp and 2 Shadow Actuators TES100SS (stereo) coming next week (...)

I have been using Crowson actuators under the couch for several years.

I would like to know if you have compared the Crowson linear actuator with inertial transducers like adx, aura etc.

What do you think about the tactile transducer equalization to tackle the inertial transducer resonant frequency?

5. Low bass really isn't practical with todays tactile transducers despite manufacturers claims of a frequency response down to 5 - 15Hz. Just like subwoofers, this is a displacement limited problem and not a RMS wattage limited one.
shake output ~= moving_mass * Xmax * frequency^2;
This is physics and there is no way around it. As the frequency gets lower you need to dramatically increase the Xmax excursion and/or the moving mass of the system. Think about it, all a transducer does is shake a mass. Either a bigger transducer or an array of a large number of smaller ones is needed if you want significant output at low sub sonic frequencies.
6. I haven't done any accurate measurements of this but it seems that the RBH and Aura transducer ring a bit after a transient occurs. I believe the transducers are not critically damped or even highly damped oscillators on a spring. This most likely (by definition) is due to their high Q resonant nature. Since you feel and don't really hear the transducers this is not as serious of a problem as it would be with conventional drivers. EQ-ing, which effectively lowers the Q, helps this.

http://www.baudline.com/erik/bass/tactile_faq.html

Stephen Smyth Collaborator on August 6
@Christian Hampp
Had not considered equalising the tactile output. It sounds like a few bands of parametric EQ (select centre freq, gain and Q) in the lower registers would suffice.

Christian Hampp on August 6
I have a seperate loudspeaker management system (Behringer DCX 2496) between the realiser and the headphone amp to do a subsonic filter for the headphones and to do equalising for my tactile transducer (its called i-beam) because this also necessary, at least with the i-beam because it has a natural massive 50 Hz peak and then it depends on where you mount the i-beam to your chair or sofa how you feel the different frequencies, and I think this will be similar with other transducers

https://www.kickstarter.com/projects/1959366850/realiser-a16-real-3d-audio-headphone-processor/comments

 

[VandyMan]

  It would be nice if there were a computer software based version of this product.  The only hardware I believe necessary to implement this on a garden variety Windows box are the measurement microphones and the headtracker--and I see no reason why each of those two hardware bits could not be powered by USB.  
 
Such a solution would cut the price of this by probably two thirds or more, and I'm sure deliver every bit as good a result.

 
It is likely that the hardware has one or more DSP chips, chips for decoding HDMI, and other specialized chips. Most computers would not have the power to support 16 channels of DSP.

 

[phoenixdogfan]

Disagree, and even if that's true, for how long do you think it's likely to remain true?  I remember when 24/96 was a huge deal,and how about room and speaker correction.  Remember the $7-8 k boxes that were sold in the '90's and early 2000's for those tasks?  Now we're using $300 programs for DSP and selling $100 DACS which to 32/384 PCM and 4x DSD--and how much program material do we even have for 7.1, let alone  16 channel audio?
 
The sooner we lose these boxes the better.

 

[darinf]

   
It is likely that the hardware has one or more DSP chips, chips for decoding HDMI, and other specialized chips. Most computers would not have the power to support 16 channels of DSP.

 

  Disagree, and even if that's true, for how long do you think it's likely to remain true?  I remember when 24/96 was a huge deal,and how about room and speaker correction.  Remember the $7-8 k boxes that were sold in the '90's and early 2000's for those tasks?  Now we're using $300 programs for DSP and selling $100 DACS which to 32/384 PCM and 4x DSD--and how much program material do we even have for 7.1, let alone  16 channel audio?
 
The sooner we lose these boxes the better.

I know first hand that most modern computers can easily handle 8 channels of "Realiser-like"processing. We have also tested 16 channels and it's not a problem. This is also while a media player app is decoding a 1080p H.264 video file and decoding 7.1 Dolby or DTS audio.

 

[jgazal]

I know first hand that most modern computers can easily handle 8 channels of "Realiser-like"processing.

What does "Realiser-like processing" exactly mean?

Does it also process azimuth and elevation head movements dynamically (i.e. head-tracking in real time)? What interface is used to connect the head-tracking device to the personal computer?

How does the user measure his/her HRTF?

 

[darinf]

What does "Realiser-like processing" exactly mean?

Does it also process azimuth and elevation head movements dynamically (i.e. head-tracking in real time)? What interface is used to connect the head-tracking device to the personal computer?

How does the user measure his/her HRTF?

Realiser-like refers to our "Out Of Your Head " virtual speaker software.
 
You're right, Out Of Your Head doesn't do head tracking, so there would be additional processing required to do real-time head tracking.
 
For HRTF measurements, you can use a Realiser or use generic HRTF's. It depends on whether you have access to a speaker system that you can do measurements too.

 

[phoenixdogfan]

But as a hypothetical, Darin, a purely software based program could do everything OOYH currently does AND do head tracking  and make PRIRS on either a Windows or MacBook box in 16 channels without issues? 

 

[darinf]

  But as a hypothetical, Darin, a purely software based program could do everything OOYH currently does AND do head tracking  and make PRIRS on either a Windows or MacBook box in 16 channels without issues? 

I don't want to derail this thread too much, but, yes, in theory, we could do head tracking with head tracking hardware or even using a webcam. The measurements are not a problem with in-ear microphones. Laptops or desktop computers have plenty of power.

 

[phoenixdogfan]

I don't want to derail the thread anymore either, but the one thing I do want to share is the existence some extremely advanced off the shelf head tracking hardware units which are small, economical, use inertial tracking, have 9 DOF, communicate with your computer via USB, and have their own software shell ready to accept ported data from programs like video games and the like. Possibly one of these hardware/software solutions could marry quite well with an otherwise software based speaker emulation/recreation software system.
 
In any case here is the link.  https://www.tindie.com/products/movsensllc/trackimu-diy-kit-imu-based-wearable-head-track/

 

[VandyMan]

  I don't want to derail this thread too much, but, yes, in theory, we could do head tracking with head tracking hardware or even using a webcam. The measurements are not a problem with in-ear microphones. Laptops or desktop computers have plenty of power.

That may well be true, but I've heard the A16 and I've head OYH and the A16 blows it away. Not even close.

 

[castleofargh]

 

  I don't want to derail this thread too much, but, yes, in theory, we could do head tracking with head tracking hardware or even using a webcam. The measurements are not a problem with in-ear microphones. Laptops or desktop computers have plenty of power.

That may well be true, but I've heard the A16 and I've head OYH and the A16 blows it away. Not even close.

because the A16 is calibrated on your own head when OOYH uses a default calibration. and then you add head tracking to the A16 of course.
if you could insert the same measurements done at your ear canal, you could then make use of something like OOYH. I tried to do that poorly with a result about the same grade ^_^. using some HRIR that seem to work ok-ish for me, OOYH, and the Wave NX head tracker. a little hard to avoid redundancy that way, and I failed at using multichannel albums using a different HRIR for specific positions/channels which would have been the ideal option. I was trying to do that with virtual cables and beyond stereo I'm really a noob.
but for basic 2 speakers simulation, it's not impossible to get a fairly good result even with what already exists. so you can imagine with a little work to blend the different steps into one software, and proper ear canal measurements, it should be perfectly doable.
the only real trouble comes from head tracking as the delays need to stay small and the refreshing rate pretty good, so fooling around with some intense IIR and massive buffer settings might not be an option, and the CPU might need to be better than Pentium3 ^_^. 
it's coming, one way or another, the difficult choice is to make something for most people using an average setting, or custom with all the extra work and equipment it may require. many manufacturers are interested in making good 3D audio now that we have the VR googles for games, but most of them wish to find average targets instead of full customization for the best result. some let you set, or will measure the size of the head and make a model based on it, it's already better than nothing. the mics in the ear like Smyth does is obviously the best method right now, but it doesn't have to be limited to Smyth, and maybe soon enough some rapid scan of someone's head and ears will be enough to general a HRTF model.  all this is only the beginning.

 

[phoenixdogfan]

Interestingly enough, in addition to an off the shelf solution for head tracking, there also exist off the shelf solutions for in ear measurement microphones.
 
https://www.amazon.com/LOW-NOISE-EAR-BINAURAL-MICS/dp/B002N6PAMM/ref=sr_1_3/160-8024924-0971048?s=electronics&ie=UTF8&qid=1486573227&sr=1-3&keywords=in+ear+microphone

 

[jgazal]

Interestingly enough, in addition to an off the shelf solution for head tracking, there also exist off the shelf solutions for in ear measurement

I already have binaural microphones.

What software would you recommend to play sweeps, process and create an spatial acoustic data file format (in AES69-2015 standard for instance)?

Does any of the before mentioned off-the-shelf head tracking devices use such AES69-2015 data file to filter audio and video files in real time?

IMHO, new entrants are always welcomed to improve competition.

But do they know how to program an algorithm that interpolates the HRTF between the measured head positions? And then delivers a rectified digital stream according to the listener head position in real time?

If OOYH software don't do that, how do they know for sure the computing power such algorithm would need? How do they know the efficiency of an algorithm they are not familiar with?

I don't know if a vast majority of consumers listen to music or watch videos in personal computers. If I were asked, I would guess the vast majority listen to music and watch video content in portable devices, dedicated digital players and smart TV's.

Regardless of the choice for DSP's in a box instead of a cpu from a pc, I believe Smyth Research brir exchange business model allows studios to invest in rooms to be measured by A16 users and I would like to have as many as possible available to purchase in their exchange site.

There is no guarantee that software developers with generic binaural room impulse responses would pay royalties to the owners of the location of the presets offered.

What's your opinion?

 

[Evshrug]

Realiser-like refers to our "Out Of Your Head " virtual speaker software.

You're right, Out Of Your Head doesn't do head tracking, so there would be additional processing required to do real-time head tracking.

For HRTF measurements, you can use a Realiser or use generic HRTF's. It depends on whether you have access to a speaker system that you can do measurements too.

I don't want to derail this thread too much, but, yes, in theory, we could do head tracking with head tracking hardware or even using a webcam. The measurements are not a problem with in-ear microphones. Laptops or desktop computers have plenty of power.

Just adding, using a webcam for head-tracking is MUCH easier with high contrast, such as the method employed by PlayStation VR. Works about as well as the PS VR which is to say pretty well, but PS VR has the advantages of stereo cameras for depth perception and lights attached to your head to make it super easy for the camera to track it.

That may well be true, but I've heard the A16 and I've head OOYH and the A16 blows it away. Not even close.

I want to write a CanJam NYC Meet Impressions post today so I'm only going to take a short break replying here. Darin Fong is an industry insider with his own product; the nice thing is it's completely software based so you just need a computer, and he has a library of rooms with speakers for sale to customize without taking personal measurements. And, you can use it as a modular piece of a whole system.

The A16 Realiser still holds the overall advantage for particular reasons.
It works with any source: a Windows/Mac/Linux box (I collectively call these PCs), a UHD blu-ray player in your home theater, a game console, you could even connect a Sony Walkman CD player and emulate a 2-channel hi-fi speaker system with two speakers in front of you.
The work is already done: castleofargh was having some success but some trouble configuring a virtual setup, with the Realiser you don't have to work your way through that, plus you get a decent DAC and two headphone Amps. Unintended latency and lip-sync issues were imperceptible. You still can connect upgraded modules to that, but the core "vanilla" experience is still very impressive.
Lastly, sorry about this Darin, but I totally agree with VandyMan: the Realiser demo totally blew away the OOYH demo I heard at RMAF 2015. Maybe it was hurt by the Transformers movie on the OOYH demo, but at its core I had a more convincing surround imaging experience with $20 Dolby Headphone DSP products. I feel there are few movies that use surround effects any better than movies usually use 3D optical gimmicks, but even then the PRIR-calibrated Realiser watching a Dolby Atmos demo and a scene from Mad Max completely created a distinct front-center and rear surround imaging locations in a realistic manner that was for me indistinguishable from pulling off the headphones in the middle of the scene (thus audio was going through speakers) and putting them back on again. I think OOYH would have better imaging if the HRTF used was based on Darin's head measured by a Realiser, and I spent time mentally getting used to the acoustic differences between his head and mine, but that could be a copyright/legal issue. On top of that, the OOYH was non-interactive in regards to head-tracking and speaker placement/imaging. Maybe someday there will be head-tracker apps created to plug-in directly to work with OOYH seamlessly, but today you almost have to be a programmer to get a seamless result.

Basically, OOYH software is fine and is about par with Razer's, Creative Lab's, and Cirrus Logic's separately available software packages, with minor differences inbetween, but none of those will be on the level of the Realiser for a natural and believable experience.

 

[phoenixdogfan]

You are pointing out many of the obvious current advantages of the Realizer.  But the way I am looking at this is that there basically exists two software programs that currently require development to bring a fully software based system.
 
1. A program which captures an HRTF from the measurements of off the shelf binaural microphones and creates a convolution file from that measurement.
 
2. A software interface or shell which modifies the output of a software based program playing the convolution file listed in item 1, to modify it for the sensor related data collected by the off the shelf head tracking hardware discussed previously to produce realistic head tracking.
 
While it's true the Realizer does both of the functions, is it really so unrealistic to imagine that such solutions can only come in a multi kilobuck aluminum box?  The head tracker I outlined is able to modify visual data in 9 dimensions on a real time basis--and it works this miracle in a windows environment with presumably negligible latency.  How heroic of a programming effort is really need to modify this program to accommodate audio data when video games already have plenty of audiodata which the head tracking software would have account for to retain the verisimilitude of the head tracking function.  To me that seems like low lying fruit for a good computer programmer--especially since the software is designed to accommodate applications other than video games.
 
I will grant that at this point, there is no off the shelf program which can create HRTF convolution files--at least as far as I can determine from my investigations.  Smyth has that one all to itself at the moment,  but there is no reason I can see why that function could not become a software package similar to the ones we use for room and speaker correction convolution files like aCCourate, Dirac, and Sonarworks--we already have the binaural in ear microphones after all.
 
As for whether or not OOYH is or is not performing the actual rendering of HRTF convolution files in a manner similar to, superior to or inferior to the way Symth does, I have to plead ignorance--and so I think does everyone else b/c OOYH does not utilize head tracking or for the most part custom measurements, so we are simply comparing apples to oranges unless or until the playing field is leveled with respect to the two products--and bear in mind that the A16 is going to retail for $2000, roughly eighteen times the $125 Mr Fong charges for a basic OOYH setup.