nycebo

Hey guys,

What is resonance?

I just read all 116 posts that come up in the 996 forum on doing a search for resonance. It's not that I have any concerns; rather I just want to know what this term is used to describe. It seems that some people who install aftermarket exhausts complain of resonance somewhere along the rev band.

Does resonance describe a condition whereby the interior vibrates or drones irritably? Do all exhausts resonate? I even looked up the word in the dictionary:

"{Acoustics} Intensification and prolongation of sound, especially of a musical tone, produced by sympathetic vibration."

I'm lost and feel like I am missing something when people describe it. Any chance you guys have a recording of resonance?

Thanks.

emty

you said it: drones irritably.

gota911

Think of the bass sound in some of the young kids cars when they have the volume turned up and drive by your car. The bass can not only be heard, but also “felt” due to vibration in your car induced by the bass sound.

Some exhaust systems will “resonate” at certain throttle and speed values. When this happens, it usually is not a prolonged reverberation of the sound inside the cabin, but it is noticeable. It is a little disconcerting when you hear it, almost like the “bass vibration” mentioned earlier. Someone else here can, and probably will, give you a better explanation of resonance.

rountreed

Difficult to describe I would say think of it like some kid with a car with really big woofers and the vibration it makes at certain tones except this would be more like at a certain rpm range. Worst case would be say at the rpm range of say 70mph in 6th gear, perfect to drive you crazy on a long trip. Never recorded and my current car does not do it but my old corvette did and I hated it. Not sure exactly what causes it but my guess would be 2 different or same materials connected together were a vibration might begin only at a certain harmonic frequency. Sorry looking back at this I probably did not do you any good but trust me you do not want it.

rountreed

Guess I hit send too late but I guess me and gota911 agree on the woofer kid thing

gota911

You know what they say about great minds thinking alike...

rountreed

Funny thing is I have a Lappis Blue 911 except mine is a convertible, just like in real life the hard top is faster and I guess the computer operator has faster fingers

nycebo

Thanks guys, I'm starting to get the idea. So is it more of a buzziness in the cabin noticeable (both by sight and feel) by vibrations coming from the dashboard, center console, and what not?

gota911

No, you will not "see" it. You will hear it (65% of the total resonance sensation) and feel it (35%). Just "guessing" on the percentages.

Palting

Go test drive the new Boxster, 987S. Go on the highway and go at a steady speed of 55-60 mph on 6th gear, with the top and windows up. The smoother the highway, the better. You'll "sense" a drone, a resonance. Pretty annoying, and can drive you crazy on loooong trips. "That's right, officer. The resonance drove me to drive at 170mph to get away from it. I plead temporary insanity" .

Riad

I have had some girlfriends with resonance... talking about droning that drives you crazy!

aben8057

I hear resonance when my wife is bitching me out or is that selective hearing?

TT Surgeon

Just tune her out, think pleasant thoughts, like your porsche.

wross996tt

Exhaust mod for the wife...hummm...great idea! Europipe stage 2 quiets for the wife...tax deductable.

Nicolaasdb

I can't block her out.....I wish it was like resonance.....I always have to yell back.....gives me a good reason to take the P out for a senseless drive and experience resonance I can live with every day..for the rest of my life....I don't know if I can say the same for the wife!! Just kidding!! You never know she might find this link somewhere!!!