UsernameProtected

Hi all. I've done this with my former C6 Z06, and received some feedback that I worked to incorporate into this test. This is a long post, so feel free to ignore, or skip ahead.

Let me preface this from the start...yes it's a sports car...yes some noise is to be expected, and appreciated. That said, my preference is to hear the "right" kind of noise, which is the exhaust note, and reduce the "wrong" kind of noise, which is from the tires on pavement.

Many of us have installed block-it mats in our Corvettes and reported improvement in interior noise levels. I've tried to quantify this, to ensure it's not just a "I paid money for it, it must be working" justification.

A reduction of 3 dB is considered noticeable, about 6 dB seems to be perceived as about half the original volume.

One criticism I received from my former attempt at this was that my measuring device was not "professional enough". This time I bought a Reed R8050 Sound Level Meter - about $130 on Amazon. I found it didn't read much different from the AudioTools app on my iPhone 6+ - if anything, it measured about 1.5 dBA higher. As a result of my findings, I'm just going to present the data from the iPhone app, as it's easier to get a photo of, and it also has a frequency analyzer feature, rather than just producing one number. One additional benefit to using this combination to test is that others can more easily repeat the tests for themselves if they like.

The block-it mats I used were actually from my former C6Z. I had to cut the rear mat just a little to fit it into the C7 cargo compartment. It also has about a 1/2 inch gap on both sides, though I don't think that's really significant.

I conducted a before and after test at 65 m.p.h., on the same section of interstate, attempting to keep distance between myself and other traffic to prevent additional noise from affecting the results.

I immediately noticed a reduction in tire noise at highway speeds. It "seems like" a reduction in objectionable noise of about 60%-70%. The exhaust tone doesn't seem "louder", but it does seem more audible...not as drowned out by the higher frequency tire noise.

The iPhone was mounted near the infotainment screen. I noticed no significant difference in sound level between that position and holding it near ear level, so for ease of taking screen shots, and repeatability, I left it mounted for the tests.

I used the "A" weighting. I tried "C" weighting, but the readings were in the 90-93 dbC range. "C" weighting seems to really emphasize very low frequencies, which are not generally annoying. I also used the "slow" setting, to reduce variability over transient bumps and expansion joints.

The car is a 2016 with Z51 and 3LT. The tests were conducted in Sport mode. There was no measurable difference between Sport and Tour modes at stable highway speeds. The stereo and hvac system were off for the tests.

Several readings were obtained. The data presented is the median readings from the tests. One error I made was not ensuring the scale is the same on the before and after 65 m.p.h. tests. My apologies for this, as it was over a week between tests, and I didn't realize the scale had been changed.

Baseline:



After modified C6 Block-It mat installation:




It appears the Block-It mats produce approximately 4 dBA sound pressure reduction. The sound reduction in the range from about 320 Hz to 1,000 Hz, which is mostly the range where the tire noise is pronounced, seems to be around 3-5 dBA.

So yes, the Block-It mats do make a measurable difference in interior sound levels. Being able to quantify it, to back up my perception, is what I hoped to achieve. I know someone could design a more rigorous test, but for what I'm getting paid for this, I think it's reasonable.

One more for reference, at 75 m.p.h.:

Hoonose

Great stuff, thanks for posting! I was going to do a comparison with my radio shack meter, but just forgot.

Rooster OG

Nicely done, thanks for the post!

Michael A

It's nice to see this test.

I would recommend using the same scale in all your charts for easier comparison.

Thanks for posting!

Michael

LGarcia2000

Good to know. Thank you for taking the time to measure and share the results.
I wonder how much more it would improve with the BlockIt and a layer of Dynamat...

UsernameProtected

Thanks all. The Block-It mats did a good job of taking the edge off the tire noise. I've ordered a Lloyd's Luxe cargo mat, and I'll update this if I find any additional improvement.

The car runs anywhere from about 66 dBA to 75 dBA, depending on road surface, at 65-75 m.p.h. Asphalt in good condition is at the low end of the range, while grooved concrete is at the upper end.

TKO Performance

Thanks for this post and confirming what everyone has been saying.......the Blockit really does work! Pretty awesome for 60 seconds worth of work.

However, you will find that these days people are getting even more noise reduction in their cars because there's a chance you have an older version of the Blockit.
It still works great but for the C7, we made the Blockit a tic thicker and added more barrier. This same new recipe is now used in all the Blockit systems....

You mentioned you used your C6 cargo mat and cut it to fit your C7. Since the shape is different and there are gaps, yes that would also allow some noise to leak through.
Not much but we pre cut these to fit real precise and snug which also helps add to smothering and preventing unwanted noise from coming through.

So you would find your readings to be even better with a newer gen C7 Blockit mat for your 2014-2016.
Like you mentioned, yes its a sports car but no one wants irritating noise in the cabin. You want to be able to speak with your partner, use blue tooth, hear the radio & eliminate fatigue all while still enjoying that sweet exhaust note. The Blockit is the quickest most effect way to help remove unwanted noise!

You might want to try DeadMats instead of Dynamat! Lightweight and very effective.

UsernameProtected

Thanks for the info, TKO. My C6 Block-It Mat was purchased new in August of 2014, so I don't know if it is the updated version or not. I probably won't buy a C7-specific one, as I don't think the marginal gains will be worth the additional cost.

I tried to quantify the effect in my C6Z, but wasn't able to really measure a difference, though my perception was there was a reduction. I am satisfied this time that I was able to quantify a difference, to ensure there was no "I spent money on it, it must be working" bias. In this test, I didn't spend any (additional) money, since I used my existing mat, so I have no motivation to justify a purchase.

The noise reduction in the 300 Hz - 1kHz is measurable with the equipment I used, which also is a large part of the range where tire noise is pronounced.

Hopefully this helps others in the future who would like to see quantifiable benefits, rather than anecdotal reports. I admit the equipment I used isn't professional-grade, but it is widely-available, so others can conduct their own tests to compare if they wish. The AudioTools app also has better "resolution" than the sound meter I purchased, as it has a real-time frequency analyzer. Readings between the $130 decibel meter and the iPhone/app were consistenly within 1.5 decibels, so I'm comfortable with using the iPhone/app.

joemessman

I have the Blockit mats. My wife can hear like you wouldn't believe. She is the perfect test for these. She stated to me that there was a significant difference in sound reduction. That's good enough for me. I thought there was a difference too, but I didn't want to rule out wishful thinking on my part so I had her listen before and after.

BigTree

Hey UP!

Thank you for the post and measurements - I've gone ahead and ordered a set. I like the sound of the car, but why not try to tone down the noise? Thanks again for the info.

So, is this really a mod if it is not taped, glued or bolted down? Taking just 60 seconds to do without at least tape sounds like a mod-wanta-be or perhaps a near-mod.

BigTree

c8nukeZ51

Is the block-it mat system in stock and being shipped?
Got a road trip coming up in 2 weeks and wondered about availability.

TKO Performance

Yes you have an older version of the Blockit. The new recipe in the Blockits is a bit better BUT as I stated and as you can clearly see by your results, your older one still works great! Leave it!


The equipment worked out find. The app is easy to obtain and so many have an IPhone. However, the reason people say they hear more of a difference/reduction then what some readings the iPhone (and apps) provide is ......well because they do!
The iPhone and some other cell phones, have a built in high pass filter with a roll-off of around 24 db/octave below 250 hz, which means that the measurements taken by the iPhone will be highly inaccurate at these low frequencies, and will not be incorporated well into overall levels. The overall sound level is dominated by frequencies that an iPhone will not be picking up.
So people actually do hear more of a difference. But regardless your test still shows a significant drop and I'll probably aim people towards thread and your findings.
I know testing is a pain,( finding a road, dealing with traffic, mats in, mats out, nailing exact speeds/rpms at specific points...etc) so hats off sir. Thank you!
Ed

awesome.
Ed


We are making more as we speak. The new unique bonding has NO glue which is awesome (no smell, no separation...etc) but unfortunately its a pretty laborious process so it takes some time. We should have them in, in about 2 weeks so, it would be close.
However you can call some distributors and see if they have them in stock now.

Ed

C7DriverOnt

Probably best to do the wheel wells under the existing carpet with a sound deadener, given it's tire noise creating a noise issue for most. Can't hurt to add the mats but given the fact the wheel wells are right behind the driver and passenger, almost at ear level seems hard to ignore if the goal is to reduce that noise.

TKO Performance

You can, but based on what everyone has been saying and his results...you don't have too.
The Blockit suppresses and absorbs unwanted interior noise without the hours spent removing parts & pulling up the carpet.

However, sure you can take it to the next level. which is why we also have DeadMats.
DeadMats stop vibration and irritating noise. You simply cut and stick them where you want. Its hard to see in some pictures because it has a textured finish rather then tin foil like other damping products.

Rear Cargo Area.


Doors


Behind The Seat



Read more about it here: (towards bottom of the page) http://store.tkoperformance.com/20142016.html

Maxie2U

Has anyone installed Blockit DeadMats under the factory carpet behind the seat area? I'm concerned placing it on the top of the "waterfall" will not allow the carpet to lay back down with uniformity like it did when the factory laid it thereby making the round (top) of the waterfall wavy & uneven.

C7DriverOnt

Trouble with all the mat solutions is they don't actually cover the wheel wells, which is where most of the noise is generated. I would recommend taking the plastic covers off those wheel wells and using Dynamat or similar covering the actual wheels where the noise stems from. In my case I covered them with Dynamat extreme and a stick on closed cell foam over that, different materials absorb different frequencies. Use the mats as well but don't forget the actual wheels. I also covered the waterfall behind the seats with the same material.


https://www.corvetteforum.com/forums...rost-king.html

TKO Performance

The Blockit "Quick & Quiet" system is a 3 piece kit. All 3 pieces go over/on top of the carpet so you can't have any bulging carpet problems.
Does a great job of getting rid of interior noise in seconds.

If your looking to put the Blockit DeadMats under the carpet, its thin and that's what its designed to do. No problems with the carpet there either. Cut, Peel, Stick, Done.

Below is the DeadMat installed behind the seat.

plasboy

Do the C7 Block it mats limit seat travel as they did in C5 & 6 ?

TKO Performance

....They don't reduce any seat travel in the C5 & C6
The C7 (because of the sensors) I found it to very little.

plasboy

Always seem like they do to me, but Ok. Currently have a set in our C5.