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Discussion Starter #1 (Edited)
We've been back and forth, do we or don't we make a dedicated thread for the VS meter. I've been opposed mainly because of this the VS's ties to the ULF Thread. Without @dominguez1's thread, VS testing never comes to fruition. However @dominguez1, @Scott Simonian, @desertdome, @3ll3d00d laid heavy hints to the effect that we need a separate thread. Now that more data is flowing and I've missed some post and can't always find the graph posts needed, I see the wisdom in that. This will stayed tied to the ULF Thread, basically a Secondary Thread with emphasis on TR, Tactile Response, metering and discussion. This is a community test bed. Everyone can have an equal part here. The idea is the more participation, the better the data, which leads to a better understanding of how the various tactile elements and components work together or clash. The goal here is to find out how we can maximize our TR AND have fun doing it.

For starters, I will post a simplified how to using the Edge of Tomorrow Intro scene. That's been our go to scene so far do to a number of things. For instance, it's a very complex, max-out, sine wave bass drop with very specific time /frequency domain bins/blocks. It's easy to identify and compare over multiple recording platforms. It has instantaneous graphs that can be posted or even email for further analysis. It's very easy to use. And pretty much everyone, everywhere has the meter needed in one form or another. How cool is that.

I'm open to suggestion. So whatever you guys want to do here is cool with me. A lot of data such as time stamping is automatic. All I ask is that you edit the run and name it with your screen name before posting the graphs. If that's all you want to do, that's fine. If you want to continually post new graphs to you original post or replace old ones or post new ones with each new upgrade or pics of your room with the graphs it up to you. Ultimately we'll have a scorecard down the road. If it's anything like what's been posted to date, it's gonna be an eye opener and head turner.

Test Tracks

These are the current test tracks for use with VibSensor.
Courtesy of @3ll3d00d and @LastButNotLeast.

WN and Bursts
WN50-100hz
1-100hz Sines

Additional VS Test Threads

VibSensor User Guide
VibSensor User Guide Sec 2

David Gage’s Wood Platform Tests
 

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Discussion Starter #2 (Edited)
Quick Start Guide

VibSensor is a free App available to all Android and iOS users. Typically its best to use your cell phone but tablets/pads work too. VS uses the accelerometer inside your PE (personal electronic device) to measure and record the tactile response of any number of surfaces, in this case our MLP(main listening position) or primary seat. You need a source to record and we’ve been using the EoT Intro scene along with specific test tracks which are better for analyzing response across a given frequency band.


Measuring with VibSensor using the Edge of Tomorrow Intro

After DL’ing open settings and switch Units to g’s and frequency range to high. At the bottom of the screen, click the Acquire button. At Title put your user name for now or you can use the edit feature later if you’ve made several Runs and before picking one to post. Set Delay to 5 seconds and Duration to 20 seconds. Load and start the EoT clip and pause at the 20 seconds mark. Place phone on its back, screen pointed to ceiling, on your seat. Hit start and as the display counts down, hit play on your bluray remote just as VibSensor hits zero. Don’t touch the phone until its done recording the scene. Any movement by your hand is recorded. Now you can click the View Data screen and click on the run. At the top of the graph you see five displayable graphs PSD/Log PSD/Vibration/Tilt/Raw. Start at Raw and click each one from right to left so that all numerical data is displayed. Now screen cap each Graph and post here.

Acronym legend courtesy of @XBR11.
Acronyms Explained

AM - Accelerometer - A device that measures acceleration. Instrument used for measuring the vibrations from a tactile transducer, or from a subwoofer.
dB - Decibel - A unit used to measure the intensity of a sound or the power level of an electrical signal by comparing it with a given level on a logarithmic scale. In general use - a degree of loudness. 0 dB is no sound.
EOT - Edge Of Tomorrow: Live Die Repeat. 2014 action/sci-fi movie.
FR - Frequency Response - Usually a Hertz range between which a speaker can accurately play an audio signal. Said to be about the quality of the sound.
HZ - Hertz. Unit of frequency defined as one cycle per second. Examples: 20 Hz is twenty cycles per second. Deep bass. 20 kHz is twenty thousand cycles per second. High treble. In general humans can hear sounds between 20 Hz and 20 kHz.
LFE - Low Frequency Effects - Technically a dedicated audio channel on a soundtrack. The . 1 in 5.1 or 7.1. Also a general term meaning bass.
MA - Motion Actuator - Device designed to convert audio signal into movement ("shaking"). Usually attached to furniture. Used for tactile feel of bass.
MLP - Main (or My) Listening Position - Intended best seat for best audio (if everything is done correctly).
MV - Master Volume - Usually refers to decibels setting of receiver volume.
NF - Near Field - Refers to being close to the speaker, like using a subwoofer as an end table at the main listening position.
PR - Pressure Response - ???
PSD - Power Spectral Density - Shows at which frequencies vibrations are strong and at which frequencies vibrations are weak. Used by ULFers.
RG - Room Gain - A rising, low-end (frequency) response, most common in a smaller room.
SPL - Sound Pressure Level - Usually refers to measuring the decibels with a SPL meter. Technically it is the local pressure deviation from the ambient (average, or equilibrium) atmospheric pressure, caused by a sound wave, as measured by a microphone.
TR - Tactile Response - Refers to what is felt indirectly.
TT - Tactile Transducer - A electro-mechanical device that is used to create vibrations in response to the audio signal (as opposed to making sound). AKA a "bass shaker". Commonly known brand is ButtKicker.
ULF - Ultra Low Frequency - Below 20 Hz. ULF is said to provide weight/ear popping.
VS - VibSensor - An android/iOS app (for a cell phone) that uses the internal accelerometer to measure vibration (i.e. tactile response). Often used by ULF enthusiasts.


Digital Graph Courtesy of @desertdome. This is what your VS Vibration graph should look like or be as close to as possible.



Where different LF and ULF are felt on the body.


Target Acceleration curves. Disregard graph on the right. This is incorrect and will be replaced.


How tactile response effects the human body.


Four types of Damping.


Room Loudness correction for reference level SPL.
 

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Discussion Starter #5
Got the first few graphs up. Let me know if I missed you or just post it here and I'll grab it.
 

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This will be a great thread! We will definitely link this and the ulf thread together.

I promise I will find the time to contribute my vibsensor data...and can visit @laugsbach to see how crowsons behave as well.

A couple of suggestions:

Why not just use the clip of the sweep you created for the standard measurement? Not everyone has access to EOT, and you could attach the clip to the first post here.

Is it possible to set standard x and y axes so that it's easy to compare? Also, how about relative bass levels? Perhaps -10dB (factoring in hot trims), DEQ off, etc. Probably need FR sweeps and TR enablers (floor, couch, etc) identified as well.

Subscribed!
 

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Can someone please post a little explanation of what VS is, what it does, and how to interpret the data? I think many of us might be at a loss if we didn't read the ULF thread.
 

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Vibsensor doesn't let you set the range on each axis. You have to export the data and import it into some graphing tool to do that (which is quite a bit more work and you need the paid version of the software to export data).

I guess the problem with exporting the clip is that it might mean it goes through a different signal chain (unless you use an htpc), not sure the best way to avoid that.
 

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Discussion Starter #9
This will be a great thread! We will definitely link this and the ulf thread together.

I promise I will find the time to contribute my vibsensor data...and can visit @laugsbach to see how crowsons behave as well.
Awesome. Looking forward to both.

A couple of suggestions:

Why not just use the clip of the sweep you created for the standard measurement? Not everyone has access to EOT, and you could attach the clip to the first post here.
Excellent point. I'll find the post that Dom's referring to and link it later. Actually thats a more appropiate test track for this type of testing and falls in line with the various frequency response test meters we use. I'm reluctant to post that yet as I'm still fine tuning it. I need to single one out to streamline this process. Of all the various sweeps I made, I preferred the 10-50hz 10 second linear sweep. Actually a 20 second 1-50hz sweep is probably ideal.

Is it possible to set standard x and y axes so that it's easy to compare? Also, how about relative bass levels? Perhaps -10dB (factoring in hot trims), DEQ off, etc. Probably need FR sweeps and TR enablers (floor, couch, etc) identified as well.
You can isolate each axes by clicking the button at the bottom of the Vibration/tilt/raw screens. @3ll3d00d did some cool layouts with data I sent him so anything is possible. Yes, -10db of reference with sub gains at +0db then also +15db along with DEQ, Eq on, EQ off, etc are all good starting points.
 

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Good thread. Makes sense to have it dedicated so to keep the ULF thread about ULF.

"Who? Me?"



No. Not 'Alf'? ULF!

:p


Looks like I broke the system with my graph. :D Haven't done one of these in weeks. Got a bunch of new toys for the HT. New projector, new receiver (Atmos!) and finally got an Oppo to replace my aging Panasonic BD55.

All sweet gear and worth going a little broke over. :p
 

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Discussion Starter #12
Good thread. Makes sense to have it dedicated so to keep the ULF thread about ULF.

"Who? Me?"



No. Not 'Alf'? ULF!

:p


Looks like I broke the system with my graph. :D Haven't done one of these in weeks. Got a bunch of new toys for the HT. New projector, new receiver (Atmos!) and finally got an Oppo to replace my aging Panasonic BD55.

All sweet gear and worth going a little broke over. :p
Very Nice. That sounds like a major upgrade. I saw those new top surrounds hanging. Doing a bit of that myself. Trying to get this all done before this weekend as out of staters dropping in. Yikes:eek:! Did you go with the 103D? Broke is good as long as its the right type;).
 

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Discussion Starter #13
Can someone please post a little explanation of what VS is, what it does, and how to interpret the data? I think many of us might be at a loss if we didn't read the ULF thread.
Very basic start guide is up for now but will go into more detail answering these question tonight and in the coming days and weeks. And if someone beats me to it or whats to grab certain posts from the ULF thread, go for it.
 

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Because I can't help myself: Not ALF or ULF, we're talking about ELF!

I've been following along on the other thread, and I'm really glad to see this moved into its own thread finally. I love the work that's been done so far. I just wish my new build was ready so that I'd have some data to contribute. For now I'll keep watching from the sidelines and hopefully throw out a useful idea every now and then.
 

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Very Nice. That sounds like a major upgrade. I saw those new top surrounds hanging. Doing a bit of that myself. Trying to get this all done before this weekend as out of staters dropping in. Yikes:eek:! Did you go with the 103D? Broke is good as long as its the right type;).
Yep. Got the 103D. It's great!

I have a rather unorthodox setup as the current limit for overheads is four for a total of a 7.1.4 system. I have a 7.1.6 system and I am using three receivers total to do it. One main Atmos receiver and two extra Prologic2 receivers to decode stereo middle overheads from the front and rear overhead speakers.
 

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Discussion Starter #17
I will Start bringing over relevant post and data from the ULF thread.This one explains what the notations displayed on the PSD and Log PSD graphs mean and why their used.

 

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I have only loosely follow the info in the ULF thread but, it is clear I am missing some valuable info that will better tell what is going on in my HT.
 

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Discussion Starter #19
I have only loosely follow the info in the ULF thread but, it is clear I am missing some valuable info that will better tell what is going on in my HT.
VibSensor is such a simple device but it's amazing at what it can accomplish. I'm really like a kid in the candy store. For example, we found room gain doesn't effect PR. I believe, with what little testing I've done so far, that the same is true with room modes. If that's the case, that's huge! Why? Because now in one column you have room gain and room modes/nodes that have no effect on PR(power response aka PSD), yet have/can have a huge effect on FR. In the other column we have EQing, voltage gain, multiple drivers and other TR enhancement components that do effect PR. Now, if we have a nasty room mode, the typical fix is an EQ cut of some sort, by way of manual or auto EQ. So now you taken something that doesn't effect PR and corrected it with something that does effect PR and thus TR. How many times have you heard someone state that they don't like Audyssey. Losing is never a good thing. Any eq cut is going to affect your PR. Now, with VibSensor, we can meter and see the effects on PR and TR. find a better way to fix room modes prior to Audyssey or any other EQ and you'll like them better.
 

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For example, we found room gain doesn't effect PR. I believe, with what little testing I've done so far, that the same is true with room modes. If that's the case, that's huge! Why?
I think there is another key point in here that I am not sure we have covered yet and that is what is the important frequency range for TR? I think I posted a link that indicated that the human body is most sensitive in the UUULF range (like 1-4Hz or something like that) which is an unrealistic target for any system without room gain. However the question is how much less sensitive are we at 10..20..30..n Hz? How much TR is enough to give the effect without being distracting?

I doubt there is a way to do it blind (deaf) as you can't exactly block out 110dB to separate TR from FR but perhaps it might make an interesting test for a GTG? Do some narrow bandwidth sweeps and poll people for a quantitative rating on sensation and try to correlate that to vibsensor data? Dunno what a good method is to try to zone in on what really counts

Point being that most modal ringing is higher in the range so determining where eq has a negative impact is important for deploying subs if you have limited space and can't address all the modes actively. Similarly there is the question of how big does your near field need to be (if that is your method) as smallest drivers simply cannot shift the air to go really deep (hence is optimal a few big or more small).
 
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