Collection of Tactile Transducer postings by Erik Olson

(most recent posts added at the end)

Noah Katz wrote:

: You've got a pair of Rane PE-17's for your subs, right? Now I do, too.

I use one PE-17 for my subs and the other for my tactile array. Why do
you have two PE-17's? Stereo subs? I'm not sure thats a good idea, EQ'ing
 I mean, I'll have to think about that one for a while?

: How did you adjust them? I suppose an RTA at minimum; what I wonder
: is, are the usual fixed 1/3-octave bands sufficient? It seems that
: ideally you'd want sweepable frequencies to really pinpoint the center
: frequency of the modes.

You are right, 1/3 octave analysis bands are not sufficient. If thats
all that you use then you really aren't "that much" better off with a
 graphic EQ over a parametric.

I used a 1/3 octave RTA for starters/checking and then I used some 1 Hz
resolution plots I made using a digital function generator and a Radio
Shack SPL meter (I corrected the plot for C weighting). I also used the
sine wave source as a way of pinpointing my desired center frequency.
This wasn't the best way of doing it but it worked.  An FFT based analyzer
 with a calibrated mic would be the best tool.

Some basic EQ rules:

First rule of advice is always treat the room first. Equalizing fixes
frequency domain problems with the side effect of causing time domain
problems. This goes for crossover adjusting too, its the same problem
since you are modifying the frequency response, many people don't
realize this.  Also an equalizer is useless without the proper tools to
set it up.



BLAZE35651 wrote:
: Has anyone directly compared the Clarks to the Aura Pro Bass Shakers?

Or to the RBH transducers which are like the Aura Pro's but more powerful.

The RBH's and the Aura Pro's have a fairly peaky response in the 45Hz
region. I'm talking big hump here.  The designer of the Clarks claims
that the Clarks are flat, I haven't seen any plots yet, and I seriously
doubt their flatness and their claimed frequency response down to 5Hz.
But I do believe they are much better than the RBH's or Aura Pro's.
I'm thinking of getting a pair of the Clarks just to measure their
performance and plot some charts.

The RBH's and Aura Pro's don't work that well with rhythmic music due to
their peaky resonance.  They are in serious need of equalization.
But you can't beat the RBH's shake per buck value.

Are the owners of the Clark Transducers happy with their music performance?

The coolness effect of transducers is great, thats a given, but I question
if the high end audio community will ever take tactile transducers seriously.

Talk about resonances.  With a transducer, the floor or your couch is now 
acting just like a paper speaker cone.  The masses and materials involved
with the transducer <--> environment coupling make designing a flat subwoofer
look like childs play.  It is one ugly, complicated equation I don't even
want to think about.  But despite that I have gotten good results with 1/3
octave equalization though.

Another problem with transducers is that they suck power.  They just don't
have the dynamic range that a decent subwoofer has.   If you play movies
near the 0dB reference level then I doubt you will be able to achieve
matching output levels with the transducers.

At low volumes though, the transducers are great because they give you the
big bass feel with out the ear fatiguing SPL levels to match.

Transducers have some serious problems inherient to them and setting them
up "properly" is NOT a trivial task, but I do love mine.  4 RBH's and a 150
watt amp.  I calculated I need about 16 RBH transducers and 2.5kW of power
to get the output levels I want!  (:  Or maybe I should just buy 2 Velodyne
FR1800 subs instead.

Here are some URL's:


MMalo22222 wrote:
: I got a Clark transducer 8 or 10 months ago to supplement my Fosgate System
: ...

Attn: transducer owners.   Have any of you measured the max SPL levels
playing pink noise that you can get out of your transducers with a Radio
Shack SPL meter?  I admit that this isn't the best way to measure a shaking
force, an accelerometer is called for, but no one has those and everyone has
a Radio Shack SPL meter.  I set my meter on the center of the center cushion
of my couch pointing forward.  Holding the meter lowers the reading a couple
dB and holding the mic end on your chest is too difficult to get accurate
numbers.  So setting it on he cushion is a good comprimise.

I'm curious what type of numbers you get.

I have 4 RBH transducers and 150W amp in a 200+ pound leather couch.

With out EQ I get around 91 dB C SPL with the RBH transducers and with some
serious 1/3 octave that number drops to the mid 80's.

For comparision purposes I get 112dB C pink noise average with two 12"
Boston Acoustic subs powered by a measely 100W total.  My subs are EQ'd to
be fairly flat in my small - medium sized room.  Corner placement gives a 
of room gain and EQ'ing makes the response flat but lowers the max SPL a
couple dB.

My mid end subs have more than a 20dB dynamic range advantage over the RBH
transducers.  IMO this is a serious mismatch.  But nevertheless my
transducers are a heck of a lot of fun.

I look forward to hearing from individuals who have done similar experiments
and measurements.


sriharan sriniwass wrote:
: Does anyone have an opinion about the benefits or the shortcomings of 
: tactile sound transducers (e.g. Clarks) vs a powered subwoofer?

Transducers suck power and they do not have the dynamic range a decent
quality sub would have.  If you listen to moives near 0dB then you'll need
lots of transducers and lots of amplifiers to match the volume levels
to the sub.

Did a test with a friend.  Everything level matched, disconnect the sub
and he couldn't tell the difference bass-wise.  Subsequently another friend
whose wife doesn't like big boxes in the living room is considering using
transducers in place of a sub.  I wouldn't do this, but transducers do have
a certain spousal acceptence factor.

: I suppose : the transducer's effect is limited to the furniture it is
: attached to. 

Not really, the transducers shake everything in the room.  The effect is
partially isolated to the object mounted to, but when I do a frequency
sweep on the transducers in my couch I can make the window blinds that are 20
feet away buzz at around 72Hz.

: some idea of price to performance will be helpful too.

The Clarks are expensive.  The RBH's and the Aura Pro's are cheaper but
have a bigger hump in their frequency response.  A decent sub will cost
you as much as a full transducer setup but the sub will play a lot louder 
and flatter.

Some people have commented that transducers and music don't mix.
I strongly disagree, what doesn't mix is peaky bass response and music.
EQ those tactile transducers and you'll be pleased.  I thought the Clarks
fared better with music than the others but Clark owners have been
complaining about their musical qualities.  Maybe the Clarks aren't as high
end as their price suggests?  I don't know. I guess this requires more


laydo45 wrote:
: >A couple of days ago I walked into my local car audio and they had just
: >gotten these Bass Shakers in and he was in heaven. He was totally trying
: >to make me buy a pair and I must say that the idea sounds good, does
: >anyone have any experience with these? I am going to be running 2 JL

: are these anything like the Alpine bass engines ?

Yes, Alpine Bass Engines and the Aura Bass Shakers are the same product.
Get the Bass Shaker/Bass Engine Pro's, they can handle more power than the
lower end product.  Also look at the RBH transducers, more power handling 
and more kick.  

The above products have a very strong resonant peak at around 45Hz.
I find this irratating when listening to music.  I had to EQ the heck 
out of them to make them listenable, unfortunately this added fidelity
came at the expense of reduced punch.  I have 150W powering 4 RBH
transducers under my couch.  Yes I said my couch.  With drastic EQ on I
get a max SPL of almost 90dB C, its the transducers shaking the floor
and couch like they were a speaker cone.  Nice tactile effect, but they
aren't loud enough to do diddley for max SPL.


John Sheridan wrote:
: Crutchfield describes them as for those who want some physical effect
: without noise violations. Of course, subs would be better in most cases, but
: if they make em, it's for a reason and somebody will find a use for them.

The cool thing about transducers is that you can get the effect of loud 
monsterous bass without the loud SPL's that will hurt your ears.  

: I still think subs are a better idea for SQ's sake.
In a car you might be right.  

Here are a couple of the problems with transducers:
* Transducers suck power, at low listening levels, sometimes my 150W amp
  is maxed and runs out of steam.  That is even with 4 RBH transducers.    
  Don't try running transducers in parallel or series with you sub speaker
  wires, they need their own amp.  Like I said they crave power.
* The RBH and Aura/Alpines have very strong resonant peaks around 45Hz.
  Their frequency response is far from flat and I would NOT call this
  quality bass.  Serious EQ helps here.
* they don't have the dynamic range of sub woofers.  If max SPL is
  your game then transducers are not for you unless you're willing 
  to mount 64 transducers under your seat and power them with around 
  10kW of juice.  Yes, a little silly, and you still wouldn't get 
  anything under 20Hz or near 150dB.

Don't get me wrong, I love my transducers, the effect is cool but
you have to approach this problem slightly differently than you would
a subwoofer.  It's a different set of problems, but they can all be 
worked around.

What I would like is if a big speaker company like Cerwin Vega, MTX,
Orion, Kicker, ... would get into making a monster transducer, something 
with a huge voice coil and magnet structure.  What is needed is a large 
moving mass to get those low Hz and high SPL's.  A larger mass should 
lower the Fs.  Maybe hydraulics is the solution and not a voice coil?
Now this is an insane idea.  A belt directly from the crankshaft to a 
gear/clutch mechanism that modulates the input energy to a way out of 
balance flywheel that wobbles and causes vibration?  

erik olson


Subject: Re: Clark transducer questions
Newsgroups: alt.home-theater.misc

Scrbblkng wrote:
> Just installed a Clark tactile transducer into the center section
> On the really really low bass tones I have noticed a distinct delay between my
> subwoofer and the transducer.  Now I know this is because I have the distance
> from listening position to the sub programmed into my Meridian 565 processor
> and the transducer since it is running off the same sub out is programmed for
> same distance, only problem is I am sitting on top of it instead of being 14
> feet away as the sub is..

I had the exact same problem when I purchased my 4 RBH transducers with the
SAM-150 160W amp.  They really shook but on music with a heavy beat the
bass felt real slow and delayed.

You are not hearing the delay line associated with the sub.
Chances are your subs are about 15 feet away and you have the delay set to
about 15ms.  This is too short to be perceived as a delay, a fattening
of the sound is a more appropriate term for the 15ms range.

> In the Home theater magazine they talked about
> adding a digital delay so that I could delay the clark to play the signal at
> the same time as the sub.  Where can I get such a piece of equipment and how
> much do they cost?
I read the same article and also the article by this St Croix guy in Mix
and thought the same thing.  So I hooked up a pro digital delay I had lying
around and started playing.  Nothing worked, nothing helped.

Then I ran some pink noise through the tactile transducers and looked
at the plot on my spectrum analyzer.  Not flat, but very peaky (resonant)
at 46Hz.  Then I attached a spare 1/3 octave equalizer, did some drastic 
EQ'ing (-12dB to +12dB to -12dB swings).  The result, the frequency response
still wasn't perfectly flat, but it sounded fantastic.  The slowness, the
bass delay was gone.  

The RBH transducers like the Aura/Alpines have a resonant frequency around
40Hz.  The Clarks supposedly don't since they were engineered not to.
I have been suspicious of this "audiophile" claim, and now it sounds 
like they act like they are fairly resonant.  I have been wanting to 
purchase a Clark unit just to check it out, maybe it is far superior?
Maybe it isn't.
The resonant nature of the RBH transducers are like a subwoofer with a
really high Q value.  High Q subwoofers just don't sound fast, this is
the same phenomena I think you have encountered with your Clarks.
And maybe its not the Clarks that are the resonant problem but instead
your whole system (Clarks and couch)?
My 150W amp and 4 RBH transducers in my couch can play pink noise at 88dBC
before non-linearity (clipping) sets in.  How loud can your single Clark
play pink noise?  Not the sub level setting volume.  I place my Radio
Shack SPL meter on the center of the couch seat.  I play the pink noise
and increase the volume until I stop getting +1dB SPL for every +1dB click
on my pre-amp.  Don't worry about frying the Clark since it has a poly
switch that will protect it.  Please post your SPL values.

Check out my quest for more bass at:

It has tactile transducer spec comparisons, plots, graphs, sealed box
drivers data and simulation plots, my transducer Usenet postings and
a simple sealed_box and room_mode cgi calculator.

erik olson


Neil Koomen wrote:

> Another possibility: the Aura Bass Shakers. I believe they can be
> attached directly to chairs, sofas etc.  They work like subwoofers to
> transmit vibrations at lower frequencies, but all they do is shake the
> furniture they're attached to.  
This is a common myth.  Trust me, my transducers can shake the walls, the
floors, the venetian blinds, pictures, even the dishes in the kitchen just 
like my subs can at high volumes.  Unless you put the transducers in your
couch and completely isolate it on a floating platform (like an optical
table) then transducers are going to bother your neighbors more than
subwoofers will.   Why?  Tactile Transducer have a direct coupling to 
the building's structure unlike subs which first transmit their energy to 
the air and then to the walls.

Another misconception is that tactile tranducers don't make noise, this is
false, they make noise by shaking whatever they're attached like it is a  
speaker cone!!!   Yes, you can measure transducers with the Radio Shack SPL
meter.  And yes, if you're pushed for space they can even take the place
of a subwoofer, it won't be great, but it'll work.  Trust me, I've tried it.

erik olson


Terry McCracken wrote:

>   I bought three of the aura packs and took them apart ad fitted to my
> couches and chairs. As everyone has said a really top effect. I have the

Do you mean the Aura Interactor tactile vest?
If so, I'm curious, how much did the transducer weigh and how big is it?

>   One thing that I discovered is that the amps for the aura and my sony
> str-ga8es have very different responces to volume control and dinamics. I
> found the best way to connect to amp was through the tape moniter line
> level outs that are not effected by the main volume control. This let me
> set a certain level of shake in relation to the line level on the vhs tape
> without the main volume control getting in the way. If I didn't do this
> then at low volumes there was nothing and at movie go for it levels the
> couches were walking around the room.

I had the same problem of not having enough gain to my amp, the transducers
weren't efficient enough.  The Aura type transducers crave power, but
too much and they get hot.

I also ran them through the tape loop which solved the gain problem.
After a while I got very tired of them not matching my volume gain control
on my pre-amp.  I found it annoying trying to "ride the gain" on two amps
at the same time (main speakers and transducers).  So what did I do?

My solution was to get a separate EQ which solved the gain mismatch
problem, it is also allowed me to equalize.  To find out more read the
Tactile Transducer FAQ at:




In mustang2 wrote:
>> Your mileage is varying.  My tactile array annoys my neighbors far
>> more than my 600W into two 12" subs do.  I've found that tactiles
>> couple far more strongly to the structure than subs.
> I should have been more clear. Certainly if the couch has wooden legs
> sitting on a wood floor, you have good coupling. I have my couch sitting   
> on thick rubber pads. Originally, it was to protect my wood floor, but I
> realize it isolates the vibrations very well.

I did some tests with different insulations and vibrational coupling.
I tried hard rubber pads, soft foam rubber pads, and even 3/4" think
felt (wool-like) pads.  While they all do help a bit, it only amounts
to about 3dB attenuation of vibrational energy.  I was surprised since
I was expecting reductions in the 10 - 20 dB range.  Why this is the case
I'm not sure?  Something about 500 pounds of couch and people vibrating
at a low frequency in the room is just not that easy to damp.

> Let's get serious though, I've seen your page, and I'm talking about 
> a *pair* of TT's, not a dozon pairs ;-)

Actually it's 32 Aura TT's now and not 24 anymore.  :-P 
But I used to have 4 RBH transducers and coupled vibration was just as
much of a problem.  Having 32 tactiles and more than 1500W just allows
my system to handle more dynamic peaks and have a lower frequency
extension since I can now have more severe equalization.  It didn't 
create more of a vibration problem, that was always there.

>> > I got a couple of Aura Bass Shakers, or tactile transducers, and 
>> > attached them to the underside of my couches.  What a difference.
>> ...
>> Welcome brother, you've been seduced by the tactile side of the bass.
>> But don't be fooled, tactile transducers are not without their share
>> of problems.  Check out the Tactile Transducer FAQ at:
> I haven't got as technical with any frequency peaks as you have. You've
> really taken Home Theater to the next level. I just crank it up and enjoy,
Well thank you, that is quite a compliment and that was my original
intention of writing the TT FAQ.  When I first got into TT a couple years 
ago I just turned it up and enjoyed, but then the little problems started 
to bug me, and then I went whole hog wild trying to fix things.  What fun 
it has been.
erik olson



bobanddana wrote:
> Max are the Bass Shakers any good up agianst the Clark (tactile). The price
> is considerably obvious but how is there output? If you have some input on
> this please let me know.

someone else wrote:
>> The tactile unit that handles 135 watts cont. @ I think 3.7 pounds per
>> watt, my question is this, that is 370 pounds @ 135 watts now in plain
>> english if I put one of these to the frame of my couch in my theater what
>> can I expect???????

These numbers have no meaning whatsoever.
Every manufacturer measures this differently so comparison is worthless.
Some manufacturers such as RBH are believed to be lying through their
teeth when it comes to the specs of their Tactile Transducers.  So whatever 
you do, don't buy based on specs alone.
Now the Clark vs. the Bass Shaker battle.  A year or two ago Mr Butterworth
did a review of the RBH transducer in Home Theatre magazine, his results
were that they are basically the same in performance.  But his test was
flawed because he kept both transducers attached to a chair during testing,
the sympathetic oscillations of one effected the other.  And since
the Clark has better damping than the RBH, I believe the Clark suffered
in this test, how much and how noticable it was I can't say.
A tactile transducer is basically a "damped harmonic oscillator",
so ignoring the voice coil, assuming it is beefy enough for achieving
max extension and assuming that we are not power limited, then for 
performance issues, only three things remain: moving mass, excursion, and
damping factor.

The Clark is believed to have better damping and more mass and excursion, 
so its performance should be greater, but is it enough to justify the higher 
cost?  I don't think so, but maybe it is and I shouldn't make any statements 
until I have run extensive tests on both.     

For more psuedo-academic physics babble about tactile transducers I
recommend checking out the Tactile Transducer FAQ and the other TT
comparison report on my bass page:


erik olson


Aeon Vide wrote:
> You could be right, since it depends a lot on the room's acoustics. But 
> with two or more subwoofers and no reflections you for sure will always 
> have deconstructive interference depending on location, while with one 
> woofer you will never generate cancellation under the same conditions. 
> Obviously this is utopic, since there is no way of eliminating bass 
> reflection. 

Yes, you are right, but that was my main point, and that basically was 
"the room is the most forgotten audio component and it also happens to be
the most important audio component" and "the effects of cancelation with
multiple subs in different localations is about equal to the effect of
room modes, so you really shouldn't go ignoring either one."

> However, assuming that you have some degree of control over
> reflectiveness, you will get, IMHO, a better overall sound field,
> unless you really know what you're doing,

Bass is difficult to absorb and I am not a strong believer in "bass traps"
but that is due to my lack of experience with them.  All the charts I've
seen and all the stories I've heard say that they work but their effect
is on the order of a dB or two when in fact IMO they need to be able 
to "suck up" on the order of 10 - 15 dB of a tuned specific frequency.
So despite the fixing of a frequency domain problem by creating a time 
domain problem I believe equalization to be a more effective and practical
solution, but I could be wrong.  Only some serious testing will change my

> as it seems to be your case. Much above the abilities of the usual
> home-theater lover, anyway. Summarizing: what doesn't seem right to me
> is that there is a myth out there among the nonsavants that the
> more woofers the better.

Now I have to admit you are right, the average HT buff is most likely 
better off just putting one big powerful sub in the corner and forgetting
about the whole bass issue.  Multiple subs, equalization, room treatments,
sub placement, ...  are just too much trouble and too difficult to do 
correctly for the average consumer, but my goal is bass perfection, I'll 
never reach it, but striving for it does seem worthy.

When it comes to subs I do believe more displacement is better.   Since
the LFE channel on AC3 and DTS is +10dB above the previous 105dB SPL level
of the 0dB reference level, it takes a lot of displacement to reproduce
20Hz at 115dB.  But honestly how many people listen to movies at 0dB?  
I rarely do, I'm a -10dB to -17dB listener myself.  What is overkill
and how much bass is enough?  I think the answer is choose your listening
level, choose a worst case signal source, choose an acceptable distortion
level and then measure it in your room.  Then as any good engineer does:
pad it, double your answer (+6dB), so when it breaks your boss won't fire 
for doing shoddy work!

An excellent choice of bass source material is the DVD of The Professional,
the AC3 track is a pegged 26Hz on the LFE channel at chapter 21.  Watch out, 
this signal is a sub buster.  The signal is pure and the noise floor at 
that point on the disc is low so this makes it easy to hear any distortion.

> This is naturally very good for speaker companies. But you know that this
> is not right, don't you?

I don't try to be "right", I just try to be better!
Its a free country, you can always buy speaker company stock. 
erik olson


Health Nut wrote:
> I think his post is PERFECT as it stands.  BTW, he has a great website.
> Erik... what is your website again?   

Thank you, I'm glad you like it.


> Remember, if you want decent output at 15 Hz, with negligible distortion, 
> you WILL need multiple subs... at his website you will see  
> a chart that shows that nothing can compare to 2 Velodyne 18 inchers--You
> need at least 3 or more other brand name subs to have the same output (and
> probably with more distortion).    

For max SPL at 25Hz, three HSU TN1225HO are comparable to 2 Velodyne F1800R's
at a fraction of the cost.  The HSU is ported while the Velodyne is sealed,
so ignoring any phase quality issues and cosmetic packaging issues the 
HSU wins the max SPL / cost contest, no question.  I've never owned a HSU,
so this is not an endorsement, but if I were to buy 3 or 4 HSU's I would
definitely buy the unpowered ones and purchase my own 1kW amp.  I've heard
some people really dislike the "chessy" 150W amp HSU sells. 

> Again, as far as modes are concerned, it is a curable problem, while
> distortion is an incurable problem (if you want decent SPL at 10-30 Hz).

Now that is a really good point, I've never thought of it quite like that.

erik olson



Nov Space wrote:
> The problem with the clarks at shows is that they convey high frequencies.

Maybe the Clarks excel at this but the Aura's and RBH's also have usable
high frequency response.

So this isn't actually a design problem, it's a differing of philosophical
tactile viewpoints.  My understanding is that Clark recommends running
their transducers full range, while that effect may be cool for some demo
material like the speeders in the forest scene from the Return of the Jedi,
the effect of full range TT's  on movies is just plain strange and IMO 
obnoxious.  I believe that tactile transducers in a home theatre environment 
should be used for bass.  Using them full range destroys all imaging from the
front LCR speakers, now mixing the subwoofer output with the surround 
speaker output might be interesting.

> I made a prototype recaro chair with 5 gallons of water in the base that 
> really rocked with the RBH's.
I don't understand.  What does the water do?

Some company, years ago made a subwoofer with water bladders in them,
they claimed a patent on this concept, and they also claimed that the
water improved non-audible bass transfer, basically loud bass without the 
high SPLs (sound familiar?).  Even the glitzy Home Theater magazine reviewed 
them with their usual "dumbfounded in the face of science" journalistic 

I have a copy of the specs somewhere, but I just didn't "get it" when I
was considering a purchase.  It seemed like snake oil to me.  All the water
does is add mass and I'm not sure that this exactly is a good thing!
My experience with tactile transducers is that mass is one of the enemies.
The greater the mass the longer (more damped) the attack is and the longer
(muddier) the decay is.  IMO these both decrease tactile fidelity.

So maybe I'm missing something here, please enlighten me on the benefits
of water mass.  I still don't get it. 
erik olson



w spohn wrote:
> Bull. If you have a truly full range speaker, you are getting the
> fundamentals of what's on the recording, not just the harmonics. I
> don't know about your gear, but my speakers do a nice 23 Hz at 3dB
> down, without a subwoofer (many of which are misnamed - they are
> really auxiliary woofers meant to boost the next octave up from the
> true bass).

Well how much did that sub cost you?   How much to tactiles cost?
But then the performance of tactiles at 23Hz is poor, so a persons
priorities should definitely me subs first, tactiles second.

> The 'Shakers' don't get you closer to the music, they are in the same
> category as the sub-harmonic synthesisers or abused equalisers that in
> one case create what was never there, and in the other, artificially
> boost what was there, out of all semblance of reality.

Now this is a good argument.  

* sub-harmonic synthesisers are fun toys, they decrease fidelity.
* equalizers are abused by most people, they are not fancy tone controls,
  they are for fixing problems, the key is the word calibration.
* tactile transducers, toy or serious audio component?  Good question, 
  and there are defendable positions on both sides, I personally believe 
  that tactile transducers can be serious audio components if proper 
  attention is placed on correcting the tactiles many many problems.
Most people fail to calibrate the SPL level of their subwoofer and surround 
speakers, they do what they feel sounds good to them and that is typically 
having the subs and surrounds +12dB or more above what the calibrated level 
might be.  In my book this is gross badness.  It makes people happy and most 
people will never learn nor do they care.  So what do you do?  All I can do 
is spread the gospel of calibration.

So yes tactile transducers are another tool that can be greatly abused,
and in most cases their peaky response curve will seriously lower the
fidelity of a system.  I believe equalization is the key, but this creates
another set of problems.  For futher talk on this check out the Tactile
Transducer FAQ at:

erik olson



Max Christoffersen wrote:
>>I don't know about your gear, but my speakers do a nice 23 Hz at 3dB
>>down, without a subwoofer (many of which are misnamed - they are
>>really auxiliary woofers meant to boost the next octave up from the
>>true bass).<

> Good for you.

First off all, if I went to the previous posters house and measured
the frequency response of his subwoofer I seriously doubt it would be
23Hz at -3dB.  This flat to 23Hz sounds like a manufacturers spec and     
not something that he actually measured.  You see the effect of room modes
play a much bigger factor than most people think or care to admit.  The only
way to achieve a "flat to 23Hz" frequency response is with equalization,
shear luck, or countless hours setting up tweaking with position, absorbtion,
etc by a talented individual with some measuring equipment.  You can't do
this by ear.

Also don't think for a second that your Clarks, Bass Shakers, ... are even
remotely flat to 40Hz much less 20Hz.  I am a tactile advocate and I am 
the first to admit that the frequency response of a tactile transducer is 
far worse than the most pathetic subwoofer you can imagine.  This doesn't
mean tactiles are bad, it is just a solid starting point bounded by reality
from which improvments can begin.

>>The 'Shakers' don't get you closer to the music, they are in the same
>>category as the sub-harmonic synthesisers or abused equalisers that in
>>one case create what was never there, and in the other, artificially
>>boost what was there, out of all semblance of reality.<

> Agreed - I don't think the Clark qualifies as a shaker.

As in Bass Shaker?
Now what is that supposed to mean?
The Aura Bass Shaker and the Clark Transducer work on the same principle
and they are similar in performance.  Now the Clark might be a "higher
performance model", but they are not in two different leagues as your
comment implies.

> I thought that too until I tried the Clark Synthesis model. Have you
> tried one in your system? They can be toys, or fall into the
> HT enhancements area - but we are now in a time in home theatre where
> largely anything goes..Cinema DSP, Logic 7 - things that have no
> resembalnce to what is on the sound track and what was recorded 

Comparing Cinema DSP with Logic 7 is like grossly comparing a high end
Lexicon product with a mass consumer Yamaha product.  (:  Actually it is
You are completely missing the point here.  The Yamaha 7 channel "front 
effects" are a joke, a toy, and utterly pathetic.  While Lexicon's Logic 7 
actually is founded on a sound principle of how surround channels are 
steered, and saying it "has no resembalnce to what is on the sound track and 
what was recorded" is unfair.  Logic 7 is not all that different than the 
6.1 channel Surround EX that THX is pushing in theatre's with the "Phantom

> the Clark's simply bring out detail and out in in the's over to you
> what you do with the information - fact is it's there.

A reviewer in Mix magazine said the same thing, but I disagree.
I don't think it really "brings out detail", it more like it turns it into
a different sort of sensation, a different sort of real-ness.  When bass in
real life happens you hear it and feel it, and tactiles bring out the feeling

So what do I think ideal tactile performance should be?
Seemless integration between subwoofer and tactile.
In my system, at moderate listening SPL's, when seated in the sweet spot a
listener's ears can NOT immediately tell whether it is the sub or the tactile
that is turned off except for the fact that with the tactiles the couch
vibrations can be felt.  The only way to accomplish this is equalization.

erik olson

Back to the quest for more bass page.