# Aurasound Whisper



## Patrick Bateman (Sep 11, 2006)

I've noticed a lot of interest on this board in small woofers. I've recently measured a few for a project that I'm doing*. Here are the *actual measured specs* on the driver. You can rarely trust the published specs, so these may come in handy.

Driver Name: Aurasound "Whisper"
FS: 164hz
QMS: 4.83
QES: 0.85
RE: 6.1
VAS: 0.1L (due to the small size, I couldn't get a good read on this. This is the published spec.)

Well this drive is pretty much one of a kind. If you want a 2" woofer, this is the only game in town. Unless you count the Hi-Vi and TB drivers, which aren't even in the same league. Actually it's not even a 2" driver; the cone is actually 1.5"

Here's the pros and cons:

The Good:
- Sounds better than anything in it's class
- small cone has response out to 20khz
- absurd xmax
- cheap
- looks cool
- Even though the power handling is low, and efficiency is EXTREMELY low, this is one graceful driver. It sounds clean at power levels that are much higher than anything else this small can take. It's cleaner than most 3" drivers, even though they have quadruple the SD. That's because it has an enormous xmax.

The Bad:
- FS measures way lower than spec
- because the FS is so low, efficiency is *terrible*
- It's flimsy (made of plastic.)


* Here's what I'm using them for. A Unity horn that's going into my Accord.
http://www.audiogroupforum.com/csforum/showthread.php?t=62789


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## dBassHz (Nov 2, 2005)

Great information! Thanks for sharing. Your unity horn thread has definitely sparked some interest.


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## luvdeftonz (Aug 17, 2005)

What are using to measure this and the other small mids (the other Aura and the JBL) you recently published specs for?


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## dBassHz (Nov 2, 2005)

Patrick, where can I find more information on horn lens dimensions and how it relates to the minimum fs of the horn? I though my Loudspeak Cookbook would have something on them but they do not.


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## 97teg (Sep 27, 2006)

First off I must say that your horn design is awesome. 

Second: How is the off axis responce. Im just curious because I have a set of the ns3-194e it is doesnt sound that great once you get even a little off axis.

Ive been thinking about buying a pair of the whispers as well as the cougers and maybe messing around with a dash mounting configuration just to see what they will do. Maybe even a pair on each side.


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## Patrick Bateman (Sep 11, 2006)

luvdeftonz said:


> What are using to measure this and the other small mids (the other Aura and the JBL) you recently published specs for?


Parts Express Woofer Tester II. I've tried Speaker Workshop, but WT2 is faster. All the driver reviews I've posted were 'burned in.'


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## Patrick Bateman (Sep 11, 2006)

omarmipi said:


> Patrick, where can I find more information on horn lens dimensions and how it relates to the minimum fs of the horn? I though my Loudspeak Cookbook would have something on them but they do not.


I'm using waveguides in the new car, so the terminology is a bit different.

I emailed the inventor (Geddes) the exact same questions years ago. I wish I could quote his email, but I deleted it. I'll do my best.

First, there is no concept of "minimum fs" with a waveguide. There IS a minimum frequency where we have directivity control. And that minimum frequency is simply the diameter of the mouth. Pretty simple huh?  For example, with Geddes Summa's, the waveguide is 15" across, and goes down to 920hz.

(speed of sound / waveguide size) =
(13800 inches per second / 15 inches = 920hz)

Google 'coverage angle" & "geddes" for more.

:: PB ::


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## Patrick Bateman (Sep 11, 2006)

97teg said:


> First off I must say that your horn design is awesome.


A horn can't do this. It's a waveguide, that's why it works. Unless someon can prove me wrong, I believe that the ONLY WAY to maintain a solid image in the car FOR BOTH PASSENGERS is with a constant-directivity-waveguide. Literally the ONLY way.

This isn't my idea, Geddes came up with this a while ago. But it's an ideal arrangement for a car, since both people are off-axis.

http://www.gedlee.com/downloads/Summa.pdf 



97teg said:


> Second: How is the off axis responce. Im just curious because I have a set of the ns3-194e it is doesnt sound that great once you get even a little off axis.


Your off axis response is dependent on the size of your diaphragm. So the NS3, or any 3" driver will begin to "beam" at about the same frequency.



97teg said:


> Ive been thinking about buying a pair of the whispers as well as the cougers and maybe messing around with a dash mounting configuration just to see what they will do. Maybe even a pair on each side.


The whispers handle a surprising amount of power. You need to highpass them though. But they're not going to get even close to the loudness of a 4" or 5" driver. Not even in the same ballpark. I'm using a total of six, and I'm putting them in a compression chamber. That raises the efficiency AND the power handling. I've probably doubled or tripled their maximum SPL by doing that, so it's more like using 12 or 18 of them.


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## 97teg (Sep 27, 2006)

Sorry about the misuse of the term. Im just starting to get into the more advanced stuff. I realize you didnt invent it or anything but i do like the adaption to car. I was thinking of using the whispers or cougars along with a midbass/midrange. It would just allow me to use a lower x over freq then a normal compact dome tweeter not sure if beaming or even comb filter will be an issue. I guess ill just have to buy a pair and mess around with them.


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## Patrick Bateman (Sep 11, 2006)

97teg said:


> Sorry about the misuse of the term. Im just starting to get into the more advanced stuff. I realize you didnt invent it or anything but i do like the adaption to car. I was thinking of using the whispers or cougars along with a midbass/midrange. It would just allow me to use a lower x over freq then a normal compact dome tweeter not sure if beaming or even comb filter will be an issue. I guess ill just have to buy a pair and mess around with them.


If it were me I would be nervous about getting the crossover right with 3 drivers. There are guys out there who spend YEARS getting a 2-way xover right, much less a three way.

How about getting three whispers, and then putting them into a vertical array? I'm picturing three of the drivers stacked on top of each other. With the right xover, it would get fairly loud. Because the xmax is so high, three of them should keep up with a lot of the five and six inch drivers out there. And $48 isn't a lot to invest.

The best part is that a crossover would be super-simple. If you ran three Whispers full-range, you would get comb filtering at 2300hz, 4600hz, and 9200hz. So what I would do is run the CENTER unit full range, and then put an low pass on the TOP and the BOTTOM of the three, set at 2300hz. Does that make sense?

The xover I just described is what Dynaudio used to use for their high end models. They used to use three drivers in the array, now they use two.


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## 97teg (Sep 27, 2006)

You are talking about using 3 whispers on each side in combintion with a 6 1/2 in the door and sub correct? That does sound like an intersting setup. I do run an active setup with mids in the doors and tweeters in the a pillars right now so the setup you describe shouldnt be too hard to setup. What do you think a 12db slope or so at 2300 should be enough? How did you determine where comb filtering will become a problem? As far as aiming do you think at each other across the windshield or maybe towards the opposit listener? Id like to try to keep the amount sticking out of the a pillars to a minimum if possible.


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## Patrick Bateman (Sep 11, 2006)

97teg said:


> You are talking about using 3 whispers on each side in combintion with a 6 1/2 in the door and sub correct? That does sound like an intersting setup. I do run an active setup with mids in the doors and tweeters in the a pillars right now so the setup you describe shouldnt be too hard to setup.


If you already have something now, why are you interested in replacing it? I'm curious what you don't like about the existing setup.


97teg said:


> What do you think a 12db slope or so at 2300 should be enough?


In this application, a 12db slope is overkill. I'd do 6db lowpass, with a single cap. You see, the only reason we're using a crossover at all is because there's going to be comb filtering at the high frequencies. This is called a 1.5 way crossover. Here's a description of a speaker that's a 2.5 way, which is basically the same idea, but with two crossover points instead of one. 2.5 way

Also, you can determine the comb filtering by just measuring the distance from the center of each cone. ("center to center spacing.") The whisper is 1.5" across, so here's the math:

(speed of sound)/(distance) / 4 =
13800 inches per second / 1.5" / 4 =
= 2300hz

The comb filtering will occur at 2300hz, but also at multiples of that. So 2300hz, then a bit at 4600hz, then a little bit less at 9200, etc...


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## 97teg (Sep 27, 2006)

Patrick Bateman said:


> If you already have something now, why are you interested in replacing it? I'm curious what you don't like about the existing setup.


Well mostly coherence. I can get it decent tonally but coherance and imaging seem to be lacking. Even with t/a i cant seem to get good imaging. Maybe having left and right eqs would help. I kinda think most of the issues are due to difference in the freq responce between the left and right side either that or my lack of tuning skills. haha.


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## douggiestyle (Apr 29, 2008)

I'd like to bump this up. Based on efficiency and sensitivity, is it safe to say that a single Whisper cannot keep up with a 6.5 midbass (such as the SLS) even if you were to feed it ample amounts of power and moderately level match?

In other words, even though it can play low enough to pair with a true MB, will it be the limiting reagent in a two way set up and thus NOT be an ideal match?


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## Hillbilly SQ (Jan 26, 2007)

douggiestyle said:


> I'd like to bump this up. Based on efficiency and sensitivity, is it safe to say that a single Whisper cannot keep up with a 6.5 midbass (such as the SLS) even if you were to feed it ample amounts of power and moderately level match?
> 
> In other words, even though it can play low enough to pair with a true MB, will it be the limiting reagent in a two way set up and thus NOT be an ideal match?


My one encounter with the Whisper revealed that it has no problem keeping up with even an 8" midbass at high volumes. I would imagine the reason for the low power handling is because it was done FULLRANGE. A lot of companies do this.


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## jonnyanalog (Nov 14, 2007)

Patrick Bateman said:


> If you already have something now, why are you interested in replacing it? I'm curious what you don't like about the existing setup.
> 
> In this application, a 12db slope is overkill. I'd do 6db lowpass, with a single cap. You see, the only reason we're using a crossover at all is because there's going to be comb filtering at the high frequencies. This is called a 1.5 way crossover. Here's a description of a speaker that's a 2.5 way, which is basically the same idea, but with two crossover points instead of one. 2.5 way
> 
> ...


Hmmmm. thats really interesting. Be fore I read this post I thought about using just 2 per side. Still think I'm gonna try 2 but with the simple crossover like Patrick suggested.


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## thehatedguy (May 4, 2007)

Werewolf said a pair should be fine up to about 4k...I just asked him a couple of days a go.


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## lycan (Dec 20, 2009)

thehatedguy said:


> Werewolf said a pair should be fine up to about 4k...I just asked him a couple of days a go.


Interesting thing to remember about _two_ drivers in a line array : it's possible to position your ear to be the same distance from each driver  that minimizes off-axis cancellation (aka comb filtering).

Can't do that with _three_ (or more) drivers in a line array 

Anyway, the real question is what's the DIFFERENCE in distance from each driver to your ear? It's not simply a function of "ctc spacing", like many people tend to believe ...


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## thehatedguy (May 4, 2007)

Lay it down for us Jeffe...I'm an array newb.

Could we use the reflections on the glass to continue the array sort of like how Keele completes his constant beamwidth array using the floor's mirror image?

http://www.xlrtechs.com/dbkeele.com/PDF/Keele (2005-10 AES Preprint) - CBT Paper 5.pdf


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## lycan (Dec 20, 2009)

The first point is to recognize the unique nature of a 2-driver "array".

Imagine two drivers, each one the same distance to your ear (this is possible with two drivers, but not with anymore, in a straight line. Just imagine 3 points on a line in space, and try to find another point ... anywhere ... that's the same distance to each of the three points). Your ear is the same distance, and same angle, to each of these two drivers. How is the response ... on-axis, or off-axis ... different than that of a single driver?

Now, chances are that the two drivers mounted in a pillar are _not_ exactly the same distance to your ear. Where will the first comb null be, in frequency? Does it depend on ctc spacing? Or, more accurately, the different arrival times from each driver to your ear?


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## thehatedguy (May 4, 2007)

What makes an array? I'm having a hard time wrapping my head around 2 speakers being an array.

A single speaker cone could be considered an array of a series of points, could it not?


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## fish (Jun 30, 2007)

Can't do that with three (or more) drivers in a line array


Is this the area "Lycan's arc" can come into play?


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## lycan (Dec 20, 2009)

For two sources, the important parameter is not ctc spacing, but rather the difference-in-distance from the two sources to the ear. Simple geometry dictates that ctc spacing is only relevant in the sense that it represents the _maximum_ difference-in-distance to any point (ear) in space.

Two sources may arrive at different times to the ear (this arrival time difference may also be zero, if the distances to the ear are the same ... this is only possible for 2 sources in a line; this is not acoustics, but grade school geometry). If the arrival time difference is *T*, the first comb null in the frequency response is :

*f = 1/(2*T)*

Again ... the arrival time difference will vary, depending on geometry, from a minimum of zero up to a maximum corresponding to ctc spacing (not acoustics, but simple geometry).

For sound traveling at 1100 ft/sec, a difference in distance-to-the-ear of 1.5 inches will yield at first comb null at 4.4kHz. If the difference in distance-to-the-ear is less, the first comb null will be higher in frequency.

That's why i've offered that a pair of side-by-side whispers should be good up to about 4kHz.

Hopefully, that clarifies (a bit) why the simple rules-of-thumb for line arrays do not necessarily apply, accurately, for a line array consisting of only two elements.


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## thehatedguy (May 4, 2007)

So if you did 3 per side with saying one run fullrange and the other 2 in a .5 configuration, you would have to worry about comb filtering? Even say if you rolled the 2 off at 6 dB starting at 800-1k hertz?


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## jonnyanalog (Nov 14, 2007)

lycan said:


> For two sources, the important parameter is not ctc spacing, but rather the difference-in-distance from the two sources to the ear. Simple geometry dictates that ctc spacing is only relevant in the sense that it represents the _maximum_ difference-in-distance to any point (ear) in space.
> 
> Two sources may arrive at different times to the ear (this arrival time difference may also be zero, if the distances to the ear are the same ... this is only possible for 2 sources in a line; this is not acoustics, but grade school geometry). If the arrival time difference is *T*, the first comb null in the frequency response is :
> 
> ...


I want to have the drivers actually have a more vertical orientation; well follow the sweep of the a-pillar. You stated side by side. If I'm reading you right its more about the path length difference that driver position relative to each other?


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## lycan (Dec 20, 2009)

jonnyanalog said:


> I want to have the drivers actually have a more vertical orientation; well follow the sweep of the a-pillar. You stated side by side. If I'm reading you right its more about the path length difference that driver position relative to each other?


YES.

For two drivers, it's possible to have a foot between them ... and still have the distance from each one to your ear be identical. Zero comb filtering, zero negative interaction between the wavefronts from each driver to your ear.

This is NOT possible with three or more drivers in a straight line.

*So yes, for two drivers on the pillar (or anywhere else), the important "distance" is not the one between the drivers, but the pathlength difference from each driver to your ear.*

For more "proof", consider the classic D'Appolito arrangement (MTM). Does distance between the midrange drivers dictate the crossover to the tweeter? Better not ... i've seen (and heard) D'Appolitos with more than fourteen inches (ctc) between the midrange drivers  But if your ear is "on axis" with the middle tweet, the distance from each midrange to your ear is the same ... which means no ill comb effects from the two midrange drivers.

Its' worth repeating : two drivers in a line array offer the unique opportunity for the ear to be equi-distant from each driver. It's not possible for more than two drivers ... pull out a piece of paper & pencil, and convince yourself. Nothing to do with acoustics, _per se_ ... just ultra-simple geometry


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## lycan (Dec 20, 2009)

thehatedguy said:


> So if you did 3 per side with saying one run fullrange and the other 2 in a .5 configuration, you would have to worry about comb filtering? Even say if you rolled the 2 off at 6 dB starting at 800-1k hertz?


Yes, because 3 drivers in a straight line cannot all be the same distance to your ear (or your nose, or your pecker). So you'll need to roll-off the outer two drivers at a frequency more in accordance with classic ctc spacing rules for line arrays.

OR, you can : physically curve the array, or employ a small amount of delay to electronically curve the array


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## thehatedguy (May 4, 2007)

I have so much to learn.

You should start an array thread.


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## King Nothing (Oct 10, 2005)

This thread has me thinking about a pair of whispers in the pillars with a tweeter. Would an MTM alignment work well in the pillar?


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## thehatedguy (May 4, 2007)

I can let you know next week.



King Nothing said:


> This thread has me thinking about a pair of whispers in the pillars with a tweeter. Would an MTM alignment work well in the pillar?


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## thehatedguy (May 4, 2007)

Could you not do some sort of L-C-R network to do the same thing like used in this fullrange array:

Humble Homemade Hifi



lycan said:


> Yes, because 3 drivers in a straight line cannot all be the same distance to your ear (or your nose, or your pecker). So you'll need to roll-off the outer two drivers at a frequency more in accordance with classic ctc spacing rules for line arrays.
> 
> OR, you can : physically curve the array, or employ a small amount of delay to electronically curve the array


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## lycan (Dec 20, 2009)

just remember guys ... it's ill-advised to cut pillar metal. Those are major structural elements, designed to protect you in a roll-over.


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## thehatedguy (May 4, 2007)

Uh oh...


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## King Nothing (Oct 10, 2005)

thehatedguy said:


> I can let you know next week.


I have a pair of kicker r19s that are itching to be used. I could do an MTM that is less than the size of a 3x5 notecard. the wheels are turning


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## King Nothing (Oct 10, 2005)

lycan said:


> Those are major structural elements, designed to protect you in a roll-over.


Itll be alright, I dont ever plan in rolling over so its not a concern LOL


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## t3sn4f2 (Jan 3, 2007)

lycan said:


> just remember guys ... it's ill-advised to cut pillar metal. Those are major structural elements, designed to protect you in a roll-over.


That was only back in the old days from what I understand. A lot less metal in that area now. Newer cars use engineered glass and advanced adhesives to serve that purpose. Ever seen the tool used to cut away the adhesive on a broken windshield that's being replaced?  

I probably still would not mess with it though.


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## jonnyanalog (Nov 14, 2007)

A-pillar are more structurally important than ever. Not only do they serve in roll over portection they also help absorb the energy of a frontal collision. Also, they help in keep the car more structurally stable in turns, etc. (as do most pillars) If you look at an a-pillar of a mid-90s car compared to today's car the newer cars have way thicker a-pillars. I digress back on topic! 

Lycan-
Thank you for the insight you have provided. I need to get to measuring!


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## Hillbilly SQ (Jan 26, 2007)

King Nothing said:


> Itll be alright, I dont ever plan in rolling over so its not a concern LOL


O'rly?

I nearly rolled my GMC over into a revine one time. Luckally my frame hit just right and just scared the hell out of me on the way down the drop that seemed to be over 100' down. Drove my 2wd truck with fresh a/t tires right out of there...BARELY without a single scratch on the truck itselfWas able to pull out at an angle where it wasn't so steep. Just had a flashback typing about itStill to this day drive extra slow on curvy wet roads cuz incidents like that will mess you up for a LOOOOONG time. 

Moral of my story is to expect the unexpected.


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## King Nothing (Oct 10, 2005)

Hillbilly SQ said:


> O'rly?
> 
> I nearly rolled my GMC over into a revine one time. Luckally my frame hit just right and just scared the hell out of me on the way down the drop that seemed to be over 100' down. Drove my 2wd truck with fresh a/t tires right out of there...BARELY without a single scratch on the truck itselfWas able to pull out at an angle where it wasn't so steep. Just had a flashback typing about itStill to this day drive extra slow on curvy wet roads cuz incidents like that will mess you up for a LOOOOONG time.
> 
> Moral of my story is to expect the unexpected.


I guess my sarcasm didnt come through well in my post. it was a joke


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## bboyvek (Dec 16, 2008)

Im a believer. These "tweeters" are awesome, they are paired with my L6's and they made a day and nite difference in the overall tonality of my system and the center stage got stronger than ever. Ill be posting my review once the sls8 go in this weekend.


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## thehatedguy (May 4, 2007)

Should come over and hear mine .


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## bboyvek (Dec 16, 2008)

are you coming to the nc g2g?


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## thehatedguy (May 4, 2007)

I want to.


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## WLDock (Sep 27, 2005)

t3sn4f2 said:


> That was only back in the old days from what I understand. A lot less metal in that area now. Newer cars use engineered glass and advanced adhesives to serve that purpose. Ever seen the tool used to cut away the adhesive on a broken windshield that's being replaced?  I probably still would not mess with it though.


 I know this one is old and was recently bumped but.....Cars are simply safer today and the A-Pillars are one element that have really used modern engineering to make them stronger. I remember reading about fire rescue teams having trouble getting through the pillars of FORD Fusion vehicles with the Jaws of Life. 

New cars too tough for crash rescuers - MSN Money _


MSN Money said:



"The Ford Fusion's reinforced steel construction probably saved the lives of the 18-year-old driver and his 16-year-old passenger. But Roberts said it gave his Hillsborough County (Fla.) Fire Rescue crew fits as it tried to free them last November. Because hydraulic cutters couldn't shear the roof posts, rescue workers turned to heavy-duty electric saws, replacing blade after blade as they dulled on the rugged material. "It was just beating the snot out of the tools," adding minutes and delaying medical treatment, Roberts said."

Click to expand...

_

Here is a blog from Autoline Detroit talking about regulations:
Autoline on Autoblog with John McElroy — Autoblog

_


Autoline Detroit on Autoblog with John McElroy said:



"Cars are definitely safer, cleaner, and more efficient today. And yes, some of that is thanks to these regulations, but more of it is due to competition in the marketplace. 

So when I look at the reams of new regulations that are coming down the pike, I have to ask: Do we really need so much more regulation? Or have we hit the point where the regulators are simply trying to make sure they keep their jobs?

A perfect example of what I'm talking about involves the newest safety regulation. The latest law is a new roof-crush standard that is expected to save maybe 70 lives a year. Yet 55% of the people killed in car accidents are not wearing their seatbelts. If we put more effort into getting people to buckle up we could save 20,000 lives a year. Where do you think NHTSA should devote its limited resources?

Automakers are coming out with A-pillars that are practically the size of a linebacker's leg. Plus, to meet that roof-crush standard, automakers are coming out with A-pillars that are practically the size of a linebacker's leg. They're so big that in some situations they can block your view of a car coming out of a side street, increasing the likelihood of a crash.

And the new ultra-high-strength-steel needed to prevent the roof from crushing is so strong that the Jaws of Life, which most first responders use, can't cut through that steel. They were never designed for it. In fact, automakers had to come up with a new stamping process, called hot stamping, to make those UHSS parts. It's a manufacturing breakthrough to be sure, but it uses a lot more energy, which translates into a bigger carbon footprint. Say a cheery "Hello!" to the law of unintended consequences.

Thanks to the roof-crush standard most municipalities – which are flat broke by the way – will now have to go out and buy new Jaws of Life. Did NHTSA ever contemplate this as they wrote their standard? No, of course not. Like I said, there is no coordination between agencies. But I don't blame the agencies. In most cases, Congress prohibits them from coming up with sensible compromises on their own."

Click to expand...

_
Anyway, I plan to order some Whispers myself to try out. I think two per side might work? I won't be cutting into my pillars however.


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