sktn77a

iTrader: (2)

Actually, it didn't. If you sort by any of the speed columns, the Dodge RAM V8 comes out tops! Go figure!

comotiger

I didn't go thru the list, just followed the link to the 10 quietest cars. BTW, the Ram is not a car, so all is well 😂

SW17LS

Those Rams are really quiet

FatherTo1

True and true, and I'm sure comotiger is aware as well. It really is tough with different devices and different microphone sensitivities, placement, calibration, etc. Even certain noises, at the right frequency, will cancel each other out and sound quieter overall under different conditions. I applaud the attempt to quantify the quietness of the car, it really is a remarkable machine. At certain stoplights I do not hear anything and I mean nothing...no engine noise, no wind noise, even the AC isn't audible, and I don't hear the other cars...I just hear the whistling of my nose. At other intersections I will hear the seat fans more than anything else actually. On freeways it is mostly some subdued wind noise (mostly around the top of the windshield) and some murmur from the tires. Some grooved pavement will produce a higher-pitched thrum but that isn't too often. After a while I start to get accustomed to the level of silence and other noises start to distract me, such as some laminated kids activity sheets in the seat back pocket shaking and making that sound plastic makes when you flap it around in the air. However, I am quickly reminded that the LS is one of THE quietest vehicles in production after I drive almost any other car for a few hours and get back into mine. Whenever colleagues and friends ride in the LS, the serene quietness is a regular comment...that and they usually remark how clean the car is (which would be easier to maintain if I could convince the wife and daughter to ride in a separate car behind me).

comotiger

It's clear that there are caveats to all measurements, whether it is dB levels in the cabin or 0-60 times or braking distances unless all the vehicles are evaluated by the same folks (drivers) on the same track using the same devices on the same tires. That said, measurements (numbers) are easier to compare than descriptions. Everyone knows that the LS is one of the quietest cars ever built. What I realized by comparing my numbers with Steve's is that my older tires are the likely culprit for my slightly higher dBs. I have a pretty quiet car now. I can look forward to an even quieter car with new tires. I guess I didn't need an app to tell me that, but I had fun with it

jmcraney

I don't know how these numbers were generated, but I suspect that they were recorded on a test track. That method just gives you some idea about the car's "self generated" noise and is not very useful. I've tried to explain this several times.

A couple of years ago we had another discussion thread going on this subject. For those who are really interested in how quiet their cars are, compared to others, they can find that thread here: https://www.clublexus.com/forums/ls-...enger-car.html

I have said what I am about to say before, and gotten no support from anyone, and several have taken exception, so I hope this will be viewed as an attempt to further the discussion and not beating a dead horse.

The single most important factor as to how quiet a car's cabin will be is "inside/outside noise (sound) ratio" (I'll use that term for want of a better term). This applies to all operating conditions and any combination of conditions: sitting with the engine off; sitting still with the engine running; going any speed, windy or calm, dry or wet; dense traffic or wide open spaces. This inside/outside ratio represents how loud a sound that originates outside the car will be inside the car. If you have a sound that measures 100dB outside the car and the same sound measures 70dB inside the car then the inside/outside ratio is 30dB. This tells you how much any sound from outside will be reduced. A 30dB reduction in sound pressure context is 1/1000 and in perception context is about 1/8.

The inside/outside sound ratio is very useful for comparing cars, or almost anything. It's easy to measure, requiring only a sound meter and a test signal source.

Sound meters can be purchased or rented. You can buy a pretty good one for $60. There are apps for smart phones that will work too. When you are making relative measurements, the calibration of the meter is of no consequence.

There is a vast array of suitable test signals available, for free. I like spectrally broad signals such as white noise or pink noise but just about any sound in the audible range of sufficient amplitude to be heard in the car will likely give the same results.

An excellent signal source would be dense high-speed traffic on a multilane freeway. You would need to safely park your car close to the freeway and determine if you can hear the traffic noise inside the car - doors closed, windows up, engine off. Measure the sound level inside the car and make a notation. Then measure the sound level outside the car. Subtract the inside measurement from the outside measurement and you will have the inside/outside ratio.

If you don't live somewhere that you can use traffic noise, another possibility is a civil defense siren. Sirens are usually tested on a schedule. Position your car where your can hear the siren inside the car - doors closed, windows up, engine off . These devices usually rotate so you would want to record the peak sound level inside and outside the car and calculate the ratio.

Other test signal sources are out there - you just need to find something that is loud enough and stable for long enough to collect your data. Examples might be large commercial air conditioners, waterfalls - think of a place with a constant sound that you can hear inside your car, with the windows up, doors closed, engine off.

This will give you a very good indication of how your car compares to other cars that were characterized in a similar manner. Remember - no calibration issues.

I am confident that any improvement from applying silicone grease to the seals and gaskets will show in the inside/outside sound ratio. I am wondering if the silicone grease restores the car's isolation characteristics to like-new or if the improvement is better than new.

comotiger

Thanks, jmcraney, I missed that thread!