Drone be Gone!

[ntsantos]

I'm so proud of this I'll even create a longer post than I normally would.

I started with a custom magnaflow exhaust a few months ago buying the same rear mufflers and resonated x pipe that comes with magnaflow's exhaust kit, even the same tips. With 2.5" piping and installation, I paid less than half of what the full system costs. I chose this system because all the reviews and sound clips indicated that it was just slightly louder than stock with no drone. I was wrong. The overall sound wasn't bad, but the drone was CRAZY loud, especially up hills. I dealt with it for a few months as the drone only existed in certain rpms. Over time It started to bother both my wife and I, so I started looking for solutions. As tempting as it was, I couldn't justify the cost of the awe system. I ended up just changing out the rear mufflers to borlas, again after reading reviews and listening to sound clips. Wrong again. The exterior sound was better, but the drone was still there. I basically had to drive in S mode all the time to make it bearable.

After more research I learned about helmholtz and side branch resonators. They seemed like a cure all for sure. If you're not familiar with this, Google it, plenty of information out there. The only problem is finding the right length and size. I took the plunge and ordered a pair of 12" no drone resonators from Synapse engineering for $50 each. Took them to a muffler shop today, and even the installer was skeptical. After the short ride home, I couldn't believe my ears, NO MORE DRONE!!!

I even drove up an uphill stretch of freeway that in the past, made the drone so bad, I felt like my ears would blow. With the new resonators...Silence! I love my exhaust again.

Here's a picture of one of the resonators. Synapse recommends that they should be installed as close to the engine as possible, but there was no room so I had them installed at the rear mufflers.



If anyone decides to go this route I will add one disclaimer. I completely guessed on the size and length and got lucky. There are many different ways to do this so please do some research. But it does work.

[HackDevil]

Sound clips please


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[Barritia]

I'm also always skeptical about people who say there's no drone. It always is and it's pretty bad every time I get to hear it. I'm not sure if they are def or just like that sound. I can't stand it. Some cars drive by me at times and the drones so bad it feels like my heads about to implode yet may be way worse in the car.

Wish there was some system to measure drone on each system in a decibel kind of rating.

[all_kobiwon]

I have the full Magnaflow exhaust (off the shelf), and yes the drone is hideous. Do you have the Synapse part number? I need to find a solution. Thanks

[ntsantos]

I have the full Magnaflow exhaust (off the shelf), and yes the drone is hideous. Do you have the Synapse part number? I need to find a solution. Thanks

ND12MS is what I used. It worked for me but may not work for everyone. Good luck!

[all_kobiwon]

Thanks man!

[Adrenalin Junki]

Thanks for the write up. I've been planning on doing borla mufflers with magnaflow x pipe resonator. So now all I need are the secondary resonators.
Did you replace the front mini mufflers with magnaflow x pipe and remove center muffler?

[ntsantos]

Thanks for the write up. I've been planning on doing borla mufflers with magnaflow x pipe resonator. So now all I need are the secondary resonators.
Did you replace the front mini mufflers with magnaflow x pipe and remove center muffler?

I have awe res dp up front. I forgot to mention that in the first post.

[Adrenalin Junki]

Ok thanks for the info.

[bthomas22]

Glad to hear this, Ntsantos. I have the Magnaflow system installed and will give this a try as my drone is also horrible. I assume you went with the mild steel vs the SS...any reasoning behind that choice?

[ntsantos]

Glad to hear this, Ntsantos. I have the Magnaflow system installed and will give this a try as my drone is also horrible. I assume you went with the mild steel vs the SS...any reasoning behind that choice?

I went mild steel only because my piping is mild, or aluminized steel. If I had SS piping I would have went ss.

[madyspop]

I went mild steel only because my piping is mild, or aluminized steel. If I had SS piping I would have went ss.

Did it also change the tone of your exhaust or just eliminate the drone at low rpm?

[ntsantos]

Did it also change the tone of your exhaust or just eliminate the drone at low rpm?

No change to the exhaust tone. Mine is still loud. It just removed the annoying drone that used to occur at about 1700 rpm.

[madyspop]

No change to the exhaust tone. Mine is still loud. It just removed the annoying drone that used to occur at about 1700 rpm.

Did you have one put in on both sides?

[ntsantos]

Did you have one put in on both sides?

Yes sir.

[GolfGL]

So I did the x-pipe mod with Magnaflow last week. I love the sound. At around idle, there is a very deep sound, I like it, can't feel it so I wouldn't classify it as drone. The car is slightly louder overall.

Issue is, once the windows are up, the deep sound completely disappears. I am quite certain this is the B&O active noise cancellation kicking in. I recall reading that it disables ANC if the windows are down. From a little time experimenting, it seems like at least 3 windows need to be opened to disable ANC.

I have tried reducing Soundaktor to 0% without any effect. I have tried taping the 4 ANC microphones on the headliner without any noticeable effect.

Does anyone know how to perform a sound system adaptation? I recall another thread that mentioned this but cannot find it now. It was related to exhausts and drone and the adaptation fixing it. In my case I just want to see what it does after adaptation. Thanks.

[madyspop]

So I did the x-pipe mod with Magnaflow last week. I love the sound. At around idle, there is a very deep sound, I like it, can't feel it so I wouldn't classify it as drone. The car is slightly louder overall.

Issue is, once the windows are up, the deep sound completely disappears. I am quite certain this is the B&O active noise cancellation kicking in. I recall reading that it disables ANC if the windows are down. From a little time experimenting, it seems like at least 3 windows need to be opened to disable ANC.

I have tried reducing Soundaktor to 0% without any effect. I have tried taping the 4 ANC microphones on the headliner without any noticeable effect.

Does anyone know how to perform a sound system adaptation? I recall another thread that mentioned this but cannot find it now. It was related to exhausts and drone and the adaptation fixing it. In my case I just want to see what it does after adaptation. Thanks.

Would love to read this as well?

[Delurker]

The AWE touring exhaust uses these resonators, which is why there's no drone with it. Nice work getting a great-sounding exhaust without the drone and without spending four figures.

[madyspop]

The AWE touring exhaust uses these resonators, which is why there's no drone with it. Nice work getting a great-sounding exhaust without the drone and without spending four figures.

AWE must have them built in their cans because I had that system and also have it on my B8 S4 and there isn't anything on the outside.

[Delurker]

Yep, in the mufflers

[Sinitron]

Interesting, could you please take another picture from under the car showing exactly where the hole was cut and the resonator was welded in? I've got a little bit of drone and will give the synapse ND's a shot.

I have the Magnaflow catback 19159, but our mufflers look nothing alike, probably contributes to the resonance noise? Huge size difference:

[DB22]

Just curious:

Isn't a muffler supposed to surprises noise and the more noise it eliminates then the better the muffler?
In Harley Davidson land, just throwing away the muffler is more pleasant?

Sometimes logic doesn't make too much sense.

[ntsantos]

Here's another shot. Hope this helps.

[Sinitron]

Just curious:

Isn't a muffler supposed to surprises noise and the more noise it eliminates then the better the muffler?
In Harley Davidson land, just throwing away the muffler is more pleasant?

Sometimes logic doesn't make too much sense.

Yeah but your Harley gets A LOT louder when you remove the factory mufflers and put on a screaming eagle exhaust, right? I'm trying to make more power and have some level of sound comfort

[Sinitron]

Here's another shot. Hope this helps.

Oh, I see, they're Borla. Slightly ifferent 2.5" oval muffler case and sightly different packing than the Magnaflows... that explains the size difference.

Yes that picture helps a lot, appreciate it. There's a little pipe section between the 2.5" inlet and the Synapse piece to space it out away from the Borla unit. Was just curious how it all fit in there.

On the Magnaflow catback the mufflers are bigger and occupy more space from the swaybar to the edge of the factory sound insulation. They're pretty tight to the bumper housing, I'll have to get creative with space and placement.

Thank you!

[ntsantos]

Oh, I see, they're Borla. Slightly ifferent 2.5" oval muffler case and sightly different packing than the Magnaflows... that explains the size difference.

Yes that picture helps a lot, appreciate it. There's a little pipe section between the 2.5" inlet and the Synapse piece to space it out away from the Borla unit. Was just curious how it all fit in there.

On the Magnaflow catback the mufflers are bigger and occupy more space from the swaybar to the edge of the factory sound insulation. They're pretty tight to the bumper housing, I'll have to get creative with space and placement.

Thank you!

The best spot according to Synapse is closest to the engine. I was going to put them before the center muffler but they didn't fit. Not sure of your case but that would be the spot if it fits. Also, if you have stock downpipes, there is a lot of room by the stock resonators.

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[goliath1]

Is there some kind of device inside the synapse pipe or is it a simple 90 with a welded cap on the end?

[ntsantos]

Is there some kind of device inside the synapse pipe or is it a simple 90 with a welded cap on the end?

Just a pipe and cap.

[brodie]

Interesting! I will be giving this a try on my Magnaflow exhaust this week. Thanks

[ntsantos]

After a good few weeks with this setup. I decided to go another direction. I've been on a oem plus theme on the car and ended up installing a S7 rear diffuser and S7 sport exhaust (thanks Tireguy!)

Ive come to the conclusion that the side branch resonator is definitely legit and a low cost way to achieve your desired exhaust sound.

After much thought, I decided to put up my Borla mufflers with the Synapse resonators for sale. If anyone is interested, they'll be up on the classifieds soon.

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[goliath1]

I have the sport exhaust and love it. Just enuf growl to make me smile but keep the neighbors happy

[ntsantos]

I have the sport exhaust and love it. Just enuf growl to make me smile but keep the neighbors happy

Ot actually made my wife happy...which should make my life happy?

I'm still getting used to the quietness, as hard accelerations aren't as aggressive when I had the Borlas on.

[Midz]

What car did you add the ND12MSes to? C7 A6/A7/S6/S7/RS7?