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I just received my Block It sound deadening package which included the back mat on and the behind the seat pieces. My Corvette is a 2017 Grand Sport.
I drove the GS completely stock and used an Apple Ipone Application "DB Meter" to test the sound. I have a freeway near my house that is pretty nice pavement heading North Bound, while South Bound is pretty beat up and raises decibel level by about 7-10 DB.
I drove the GS as much as possible in the same lanes at roughly the same speeds 70-72 MPH. I did start the test from my house a few miles from the freeway, but the decibel readings were highest on the freeway. I also drove the car in "Sport" mode. I drove with the radio off and the windows up. I kept my IPhone inside the the forward cup holder standing up vertical. I tried to keep acceleration below 3,000 RPM as most of the road noise comes from the tires, but I wanted to keep the scenario as easy to duplicate as possible. I also put the GS into 7th gear (M7) once at 65MPH.
What I found is that stock on the freeway my DB Meter was reading between 78-80 DB. Going south bound, more freeway noise it was reading around 85-87 DB. The maximum DB hit at 91 DB in one particular location exiting freeway.
I drove home and installed the Block It product which was very easy just drop it in place. Most time consuming part of it was to remove the stock cargo net. I went out for the same drive as before following pretty much the same route about 15 minutes later. What I found is that the noise on the freeway noise dropped by (2) DB 76-78. The same was the case going south bound 83-85 DB. The interesting thing is that the exit resulted in a max of 91 DB exactly the same as stock. Not sure I hit exactly the same spot, but it registered in same general location. Not something I can explain, maybe sound impact is from the front end which does not have modification.
My overall opinion would be that this a nice option as it does seem to deaden sound from a seat of the pants (ears) sense. The IPhone seemed to agree as it was showing about a (2) DB drop as I kept an eye on it. Remember in the cup holder, so hands free
For the cost of $229 as I recall, easy installation or removal (Track Day) it is a nice addition. I saw that someone posted a (3) DB drop with system where you remove interior. Obviously the testing equipment and roads traveled are not the same, but you could have some comparative analysis. Maybe the (91) DB spike would not be as bad given there is more insulation on the under carpet system. Maybe it would be good to install the under carpet kit and then test, maybe even then add Block It on top and test again. Based upon simple math that would be (5) DB drop
Overall this is a sports car, but a more pleasant drive is not a bad thing, as excessive noise can fatigue you.
Keep in mind that db is not a linear measure; for example a measured +3db increase requires a doubling of the power used to generate the noise. From our ear/brain's point of view a -10db drop would be heard as a sound roughly half as loud yet it would require dropping the actual sound power to 1/10th of its previous level. This is why you aren't going to get huge db decreases from practical sound absorbing modifications AND why the law of diminishing returns quickly catches up with those putting in high powered amplifiers. To double the perceived loudness from a 50 watt output amplifier requires an increase to a 500 watt amplifier.
Also for the full picture you would need to look at a spectral display of the before and after sound deadening since different sound frequencies and characteristics are more/less annoying and more/less damaging to the human ear. In general higher sound pressure levels at higher frequencies are the most damaging and generally the most annoying/fatiguing and this is the range most easily absorbed by foam or other typical acoustic insulation. Lower frequency sounds are much more difficult to attenuate (thus the booming noise without highs that you hear from that ricer next to you with the big audio system). So the Block IT and similar add on insulation is pretty good at getting rid of the part of the spectrum that is most annoying and particularly the most damaging to hearing.
Keep in mind that db is not a linear measure; for example a measured +3db increase requires a doubling of the power used to generate the noise. From our ear/brain's point of view a -10db drop would be heard as a sound roughly half as loud yet it would require dropping the actual sound power to 1/10th of its previous level. This is why you aren't going to get huge db decreases from practical sound absorbing modifications AND why the law of diminishing returns quickly catches up with those putting in high powered amplifiers. To double the perceived loudness from a 50 watt output amplifier requires an increase to a 500 watt amplifier.
Also for the full picture you would need to look at a spectral display of the before and after sound deadening since different sound frequencies and characteristics are more/less annoying and more/less damaging to the human ear. In general higher sound pressure levels at higher frequencies are the most damaging and generally the most annoying/fatiguing and this is the range most easily absorbed by foam or other typical acoustic insulation. Lower frequency sounds are much more difficult to attenuate (thus the booming noise without highs that you hear from that ricer next to you with the big audio system). So the Block IT and similar add on insulation is pretty good at getting rid of the part of the spectrum that is most annoying and particularly the most damaging to hearing.
I just received my Block It sound deadening package which included the back mat on and the behind the seat pieces. My Corvette is a 2017 Grand Sport.
I drove the GS completely stock and used an Apple Ipone Application "DB Meter" to test the sound. I have a freeway near my house that is pretty nice pavement heading North Bound, while South Bound is pretty beat up and raises decibel level by about 7-10 DB.
I drove the GS as much as possible in the same lanes at roughly the same speeds 70-72 MPH. I did start the test from my house a few miles from the freeway, but the decibel readings were highest on the freeway. I also drove the car in "Sport" mode. I drove with the radio off and the windows up. I kept my IPhone inside the the forward cup holder standing up vertical. I tried to keep acceleration below 3,000 RPM as most of the road noise comes from the tires, but I wanted to keep the scenario as easy to duplicate as possible. I also put the GS into 7th gear (M7) once at 65MPH.
What I found is that stock on the freeway my DB Meter was reading between 78-80 DB. Going south bound, more freeway noise it was reading around 85-87 DB. The maximum DB hit at 91 DB in one particular location exiting freeway.
I drove home and installed the Block It product which was very easy just drop it in place. Most time consuming part of it was to remove the stock cargo net. I went out for the same drive as before following pretty much the same route about 15 minutes later. What I found is that the noise on the freeway noise dropped by (2) DB 76-78. The same was the case going south bound 83-85 DB. The interesting thing is that the exit resulted in a max of 91 DB exactly the same as stock. Not sure I hit exactly the same spot, but it registered in same general location. Not something I can explain, maybe sound impact is from the front end which does not have modification.
My overall opinion would be that this a nice option as it does seem to deaden sound from a seat of the pants (ears) sense. The IPhone seemed to agree as it was showing about a (2) DB drop as I kept an eye on it. Remember in the cup holder, so hands free
For the cost of $229 as I recall, easy installation or removal (Track Day) it is a nice addition. I saw that someone posted a (3) DB drop with system where you remove interior. Obviously the testing equipment and roads traveled are not the same, but you could have some comparative analysis. Maybe the (91) DB spike would not be as bad given there is more insulation on the under carpet system. Maybe it would be good to install the under carpet kit and then test, maybe even then add Block It on top and test again. Based upon simple math that would be (5) DB drop
Overall this is a sports car, but a more pleasant drive is not a bad thing, as excessive noise can fatigue you.
Excellent well documented tests!
2 db is not a bad reduction but as I recall from posts that folks reported better results were much more elaborate covering all key areas. One used two different products and covered the full thin aluminum panels behind the seats and something along the aluminum torque tube tunnel if I recall correctly (those panels must act like speaker diaphragms!) They also removed the inner rear plastic fender well covers and covered the outer with insulation. That also probably amplifies tire/road noise. A lot more work to install as seats and the full carpet in the rear were removed.
That doesn't seem like a lot of drop in DB for 230.00 or am I wrong. I would have thought it would drop more. Glad U R satisfied with the product.
I think the impact cannot just be noted as a top DB number, it is taking out some of the lower sounds, such as rocks that stick to tires and get thrown into the wheel well. There are a lot of constant noises below the 78-80 DB range that were reduced. All that I could measure was overall number, and what I saw glancing at IPhone.
I dont use sound deadeners but no matter what the cost cant expect any mat to make a dramatic difference; If it does anything at all its worth it 2db is noticeable
not referring to the op but see stuff like this lots and wonder if this is their first sports car or simply expect way too much, cant have it all
These cars are very quiet stock the C6 was WAY too quiet lol -hp makes a little noise
I dont use sound deadeners but no matter what the cost cant expect any mat to make a dramatic difference; If it does anything at all its worth it 2db is noticeable
not referring to the op but see stuff like this lots and wonder if this is their first sports car or simply expect way too much, cant have it all
These cars are very quiet stock the C6 was WAY too quiet lol -hp makes a little noise
As the OP, no this is not my first sports car. Prior I owned a Miata Mazdaspeed for (6) years driving about 20,000 miles per year. It was very loud and it was what it was a soft top sports car. I also owned a Honda S2000 also a soft top and put on similar mileage for about (5) years. The Corvette is a coupe and it is a nice car that could be made a bit more enjoyable with some additional sound deadening as I ended up doing a lot of freeway mileage. Like the other vehicles I will put about 20,000 miles per year onto the GS.
Roads in Northern California can be very nice and there is very little noise, then there are roads that make the wheels howl and noise goes way up.
Simply put out my observations for others that might want to make the ride a bit quieter and wonder about the options available.
I used the Blockit product on my extremely loud ('tire roar') stock C7 Z06. There was no reduction in tire noise whatsoever. 3000 miles on OEM run flat tires
THANKS for some real data, which is sadly lacking from the vendors (at least, I've failed to find any... sorry if I missed it somewhere). At those decibel levels it would be interesting to see what the discrimination level is for differences for most people, especially older men. I'm thinking a mere 2db could be had considerably cheaper but I already bought Blockit.
Based on the 3db reduction being "half the sound energy," the perceived volume reduction in the driver's seat is nowhere near what that would suggest, even adjusting for roughly 2/3s that.
After our first road trip in our 2014 M7 Z51, my wife and I found the road noise after a full day of driving to be irritating and wearing. I researched sound deadening and decided first try the Block-it kit because of its drop-in installation and positive reviews in the forum. After many additional road trips, including a one week 3000 mile trip with a 750 mile one-day run, neither of us have found the the noise level to be intrusive or irritating. Conversation is easier and audio player volume can be set lower. Subjectively, we both think the Block-it made road trips more enjoyable. BTW I also installed a Lloyds Ultimat deck area mat over the Block-it.
Last edited by 22101Vette; 11-05-2017 at 09:16 PM.
03-25-2017, 07:42 PM
Block-it Sound Deadening review
