brel523

I work FOH(Front of House) sound at my church and have access to a portable dB Meter. Going to pick it up tonight and record road noise in my car.

I had planned on taking the reading from the right front passenger seat about head high since that's where you would normally sit.

I was going to take a reading with the car off, car in park and idling, and then car at different speeds on highway(3 year old highway) that is very smooth. I'll try to record the dB level along with speed and rpm. May even try to set up video cam with both dB meter and gauges in same view.

I have 20,300 miles on original tires.

I was wondering what you guys(and girls) thought on this testing method. Anything else I should test or setup differently that might help record the noise level more accurately?

Thanks.

PhilipMSPT

iTrader: (5)

20+k miles on the original tires?

That will definately affect the test. It's best to get those tires changed first.

Otherwise, that would be an interesting experiment to do. I would also like to get a relative idea of noise when you have air intakes, exhaust, or the such.

Let the experiments begin!!!

brel523

The tread on the original tires is still good and I check them regularly. I do 90% highway driving on a freshly paved highway so I expect my tires to last a while longer at the current rate of wear, but will run the test again once I get new tires(before/after). I don't have $1200 for a new set of tires now but will take donations.

Currently the car is stock but planning on a Joe Z intake soon and will do a before/after test. I don't see me getting a different exhaust.

I will be taking car in for the Brake Pad TSIB replacement next week and will be getting a loaner. I'll do the test on that car for comparison also. I'll also see if they will let me 'test drive' an IS350 on the lot(with new tires) and take readings.

I guess on this test, I'm just trying to get a good reading and experiment on how I should conduct the test.

Will be interesting to see the dB difference between idle/parked and on the highway at 70mph.

EBMCS03

So whats the noise level? I think its rather loud inside...

webra

2GIS is poorly insulated for road noise. There are no barriers under the carpet. You will also find that its much noiser for roadnoise on the Driver's side. See if you can confirm this by moving the db meter from one side to the other during constant speed. Let us know!!

Koz

I have a set of 050 Bridgestones, with 2K miles on them (all break-in miles), for sale. If you are interested in them, PM me. I had to get a set of all-seasons.

Koz

brel523

OK, here are initial results. I'll do more testing but here is at least some results. The dB meters minimum reading is 40dB. Since we use this for metering music volume, there was no since to originally purchase one that read dB's any lower. I didn't know I was going to be reading dead silence in my car when we bought it.

Here's the process I used and what I was able to read/record. A/C is off. Audio is off. dB meter was sitting in front passenger seat, but mic was not touching the seat. Note: this will still show difference of dB's in the testing even if the meter is not at head high(but I'll do that one also).

1. At home(in the country) away from any city/traffic ambient noise. Car turned off. Meter: < 40dB reading and would rarely hit 40dB so I'm going to 'assume' the baseline for my experiment is going to be 35-40dB.

2. Started the car and got the high idle(~1200rpm) for a minute. Meter: 51dB-54dB

3. Car dropped down to idle speed of ~1000rpm. Meter: 43dB-45dB. Wow, almost 10dB drop from start up idle.

4. On highway, no traffic around me at 70mph/2200rpm. Meter: 55dB-61dB

5. On highway, no traffic around me at 80mph/2500rpm. Meter: 56dB-62dB

During this test, I did notice something from these numbers. The road noise seemed to be louder(to my ear) when I would slow down to a stop light, but the meter didn't seem to notice. The noise wasn't louder to the meter, but just had a different tone(deeper) to it. Make since? I think we(as humans) sometimes mistake different tones as loudness when they really aren't.

Those are the initial test numbers so far. I'll try those same test again while holding it head high next to me.

Here are some dB chart references so you get some idea of how loud typical noises are.

0dB - Threshold of hearing - Apparent Loudness: N/A, Typical Physical Response: Not audible

10dB - Soft whisper @ 5m - Apparent Loudness: 1/8 as loud, Typical Physical Response: Just audible

30dB - Leaves rustling, Very soft music, Public library, Living/dining/bedroom - Apparent Loudness: 1/2 as loud, Typical Physical Response: Very quiet

40dB - Suburban area with medium transportation density, Kitchen/bathroom - Apparent Loudness: Arbitrary Base Reference Level, Typical Physical Response: Quiet

50dB - Quiet office - Apparent Loudness: 2 times as loud, Typical Physical Response: Speech interference

60dB - Light car traffic @ 15m, City or commercial areas, Ringing Telephone, Noisy office, Normal speech, Background music - Apparent Loudness: 4 times as loud, Typical Physical Response: Intrusive

70dB - Motorway traffic @ 15m, Roadside traffic, Train horn @ 500m, Noisy restaurant, Fortissimo singer 3 ft. away, Normal piano practice - Apparent Loudness: 8 times as loud, Typical Physical Response: Telephone use difficult

80dB - Busy traffic intersection, Motorway construction site - Apparent Loudness: 16 times as loud, Typical Physical Response: Annoying

90dB - Heavy truck @ 15m, Busy city street, Lawn mower, Loud shout - Apparent Loudness: 32 times as loud, Typical Physical Response: Very annoying. Can damage hearing after 8 hours exposure per day.

100dB - Jet takeoff @ 500m, Train horn @ 30m - Apparent Loudness: 64 times as loud, Typical Physical Response: Can damage hearing after 2 hours exposure per day.

110-115dB - Thunderclap, Sand-blasting, Squealing pigs, Amplified Rock Music - Apparent Loudness: Over 128 times as loud, Typical Physical Response: Maximum vocal effort. Can damage hearing after 15 minutes exposure per day

130dB - Military jet, Air raid siren, Shotgun - Apparent Loudness: 512 times as loud, Typical Physical Response: Limited ability to hear amplified speech. Noise may cause pain and brief exposure can injure unprotected ears

150dB - Rock music peak - Typical Physical Response: Danger

Do you have 'major' problems with my testing or have any other tests to try or different test methods you want to see or suggestions/comments?

PhilipMSPT

iTrader: (5)

Cool.

So the IS does not get any louder than 62 dB.

Is it safe to say that most outside noise can be drowned out by some music playing in the cabin?

EBMCS03

Ya I was disppointed... during the test drive I didnt notice it that much but after a few hundred miles I noticed the extra noise...


Sure muic will drown it out but its not the same... sometimes in the morning I only listen to the news at a low volume

brel523

I'd agree with both of those statements if you are not in busy traffic or a tractor trailer is not passing you.

Under normal driving conditions(define normal ) I can't see road noise getting above 65dB. Like you said, turn on the music to help drown out the outside noise and/or get quieter tires.