All 991 models have it

 

No, they all have it. PSE just prevents it dominating the aural experience

 

I believe cars with PSE also have Symposer.

ChuckJ

 

I was reading in the tech manual that the Symposer is only on in Sport and Sport+, but mine is on all the time. I can't find anything in the owner's manual. Does anyone's turn off when you are not in Sport?

ChuckJ

 

I am thinking of ordering and would like to know where you got that info. I have not seen anything saying that it would switch on or off by any means and thought that it was just built into all cars. If it truly eliminated with PSE and that would be another reason for getting it.

I don't really mind the sound of it, however it does seem a bit synthetic.

 

My experience with racing old (60s & 70s) Porsche 911s tells me that it sounds just like it did when we took the air cleaners off during the races. That's because that's where they get the sound. The tech manual says it turns on with the Sport Mode button. I think mine is always on.

ChuckJ

 

I was told that all cars have it and it only gets louder (intrusive) with each driving mode.

 

Mmm...i'm very confused.
I LIKE VERY MUCH the sound of my 991, even without PSE. Really, with Sport or Sport Plus Switch turned on, i can feel (ear), better the engine or sounding it better, but i'm really not able to say if there is a substantial difference or the it's because i REV MORE my car in these modes.

Someone can clarify?

 

Can someone with PSE chime in and let us know... thanks

 

Sport button is standard on all 991. When you activate it, sound symposer activates as well. To be honest when I activate the sport +, I hear way less the sound symposer sound. But the reason could be very simple: sport + you are revving high, so you hear way more the engine. No PSE

 

Okay so we've established that Sound Symposer is on ALL 991 models regardless of PSE or not. We've also established that it doesn't sound that great.

Sooo.... how can we fix things?

 

I disconnected and plugged mine less than a week after I got the car. Very happy now.

 

The sound symposer is on all 991's and is active all the time. It is nothing but a tube from the engine compartment to the cabin. It does have a diaphragm in the tube to keep fumes out of the cabin. The diaphragm just repeats the sound waves while keeping out those fumes. When you activate PSE a different diaphragm is activated allowing more exhaust noise, so yes, more sound comes thru the symposer. You can not change the sound coming thru the symposer, but many owners (myself included) reduce the noise by blocking the tube on one or both ends or stuffing foam or rags in the tube. The only way to change the sound frequency of the exhaust system (make it deeper) is to change the exhaust system plumbing and/or mufflers.

 

Great explanation! Well written.

 

Sound Symposer (aka drone inducer) is not on all the time. It is not on in Eco mode, but in Sport and Sport+ it opens up with one of our, ahem, favorite Change Over Valves.

The sound is intake noise, so dinstinct from the exhaust noise.

Plugging it (did this in 2012) provides less belching from the intake into the cabin, belching which masks other, to me, more desirable sounds -- mechanical noise from engine and exhaust from outside.

Luckily it is easy to defeat it.

Oh, and the fact that it is not on all the time made it even less desirable to me. It comes on abruptly at whatever the RPM when the valve opens, almost so as to remind you that it is an engineered/piped-in sound.