Automatic Transmission and Exhaust Drone

[Bluemustang]

I have accepted the drone of my Gibson catback and I actually am starting to embrace the drone. Sounds like a race car to me.

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[Josh/AWE]

When studying the AWE Tuning web page I saw that AWE offers a 'AWE Tuning Sound Satisfaction™ Guarantee'.
Does the Touring-Edition Cat-back exhaust come with this guarantee?

Negative, the Sound Satisfaction™ Guarantee is not applicable to our Mustang products. We do, however, have a 30-day satisfaction guarantee (in general), in the event you don't like your newfound tone for whatever reason. Though I am confident that you'd enjoy it

 

[bodam]

What's the reasoning behind not offering the guarantee to the Mustang products?

 

[Josh/AWE]

What's the reasoning behind not offering the guarantee to the Mustang products?

The Sound Satisfaction™ was created and applied to only one application, which is a Porsche system. It is not something that is applied to multiple products we produce.

 

[LoveMyWheels]

Negative, the Sound Satisfaction™ Guarantee is not applicable to our Mustang products. We do, however, have a 30-day satisfaction guarantee (in general), in the event you don't like your newfound tone for whatever reason. Though I am confident that you'd enjoy it

Fair enough. I pulled the trigger and ordered the AWE Touring Catback yesterday.

 

[Josh/AWE]

Fair enough. I pulled the trigger and ordered the AWE Touring Catback yesterday.

Congrats! Hope you're excited

 

[LoveMyWheels]

Before taking off the Flowmaster American Thunder axle-backs I did some objective sound analysis on the drone problem when paired with an automatic transmission. It is documented in the attached video



Those are parts of a 20 minute recording of a suburban route which I took to have a reference to compare the soon to be installed AWE Touring catbacks.

The sound you hear in the video/sound is taken with a Sony FDR-AX33 camcorder. Use good loudspeakers or put on headsets and you can witness the nerve wrecking drone. The sound analyzer software is fed by a separate calibrated external microphone, which was attached to the shoulder of the drivers front seat.

 

[bubba]

Before taking off the Flowmaster American Thunder axle-backs I did some objective sound analysis on the drone problem when paired with an automatic transmission. It is documented in the attached video



Those are parts of a 20 minute recording of a suburban route which I took to have a reference to compare the soon to be installed AWE Touring catbacks.

The sound you hear in the video/sound is taken with a Sony FDR-AX33 camcorder. Use good loudspeakers or put on headsets and you can witness the nerve wrecking drone. The sound analyzer software is fed by a separate calibrated external microphone, which was attached to the shoulder of the drivers front seat.

Great job, thanks for sharing! Looking forward to the AWE touring video!

 

[Southview]

Great video. That is the drone I experience with my Roush AB. Even after removing the h pipe. If you can keep the rpm above 1600 it gets better. Over 1800 rpm if it is pretty much non existent. Good luck with your new system. I still think you should do what I told you about regardless of the exhaust. You will not regret it. :cheers:

 

[LoveMyWheels]

Just a quick update. The AWE Touring cat backs do not have the drone issue at 1250rpm - 1500rpm like the Flowmaster American Thunder axle backs. However, it appears like there are two effects in play. First, the drone frequency itself is better controlled by the design. Second, the overall interior noise level is higher which drowns the remaining drone with other, higher frequencies. I will still show the frequency analysis and post a link to a youtube video to hopefully confirm my subjective opinion.
I will comment further on the sound of the AWE Touring cat back in the broader rpm range in one of the other posts dedicated specifically to that product.

 

[smann]

I have an Auto with the Solo Axle backs. Been on for almost a year. They sound excellent. Deep growl but quiet when cruising. Absolutely no drone anywhere in the power band. You might want to look into those.

I have drone with my solos.. around 2100 RPM crusing at 70mph, 6th gear.
Did you adjust your J pipes at all

 

[Josh/AWE]

Just a quick update. The AWE Touring cat backs do not have the drone issue at 1250rpm - 1500rpm like the Flowmaster American Thunder axle backs. However, it appears like there are two effects in play. First, the drone frequency itself is better controlled by the design. Second, the overall interior noise level is higher which drowns the remaining drone with other, higher frequencies. I will still show the frequency analysis and post a link to a youtube video to hopefully confirm my subjective opinion.
I will comment further on the sound of the AWE Touring cat back in the broader rpm range in one of the other posts dedicated specifically to that product.

First, kudos to you for actually doing a frequency spectrum analysis, you've gotten a glimpse of the science we use in our world.

Second, you'll notice the correlation between when you call out "drone" in your video and the spike in the sub 100Hz range. It is this frequency range (95-100Hz give or take) that is especially bothersome to the human ear (or at least to the brain that intercepts the signals from the ear, biology topic beyond the scope of discussion here).

However, more importantly, it is the *amplitude* of the spike in that frequency range that determines if it will be bothersome (drone) or not (just a deep sound).

So while you may still see a spike in that range when analyzing our exhaust note, the amount of amplitude reduction we accomplished with our 180 Technology® is why you are not being bothered by that spike.

It's not because the higher frequencies are drowning it out, it's because we strategically targeted and reduced just enough of the amount of that frequency generated until it was no longer bothersome. It does not take much reduction to bring the threshold down below the bothersome drone zone, but it is definitely difficult to do it, and traditional approaches to sound volume reduction don't reach to that end of the frequency spectrum.

In fact, traditional approaches (perforated core mufflers) tend to *amplify* that end of the spectrum (a viscous cycle as the exhaust manufacturer chases drone by adding more "muffling"), while also unintentionally killing higher frequencies, the reason why so many "muscle car" sound exhausts out there start off sounding mean and then get quieter as you rev out the motor, while also booming badly at cruising speed. Also a reason why so many are tuned to sound exotic: the whole frequency range is shifted higher and out of the area that is more difficult to solve.

Lastly, the higher range frequency spikes you see on our exhaust signature are there intentionally: they are the pleasant frequencies that provide us all with the glorious exhaust note as you rev out.

To really kill drone while also allowing it to be packaged properly to fit under a car and also provide an exciting tone only when you ask for it takes some serious engineering (which is why it is so seldom seen in our industry).

:cheers:

 

[RNstanger]

I have drone with my solos.. around 2100 RPM crusing at 70mph, 6th gear.
Did you adjust your J pipes at all

No haven't had to adjust them at all

 

[LoveMyWheels]

Before taking off the Flowmaster American Thunder axle-backs I did some objective sound analysis on the drone problem when paired with an automatic transmission. It is documented in the attached video



Those are parts of a 20 minute recording of a suburban route which I took to have a reference to compare the soon to be installed AWE Touring catbacks.

The sound you hear in the video/sound is taken with a Sony FDR-AX33 camcorder. Use good loudspeakers or put on headsets and you can witness the nerve wrecking drone. The sound analyzer software is fed by a separate calibrated external microphone, which was attached to the shoulder of the drivers front seat.

I finally finished and uploaded a corresponding video for the AWE Touring catback, which replaced the Flowmaster American Thunder axlebacks (with stock resonator). Same driving route and identical equipment for recording and sound analysis. You can view it here:



The AWE Touring catback solved the drone problem entirely. As shown in the video the exhaust system controls the sound amplitudes at the drone resonance frequencies quite well. It practically eliminates the drone in the area 1250rpm - 1500rpm, which I consider critical with the automatic transmission.

A great Thank You to the sound engineers at AWE!

 

[The01]

Factory headers/cats with Corsa Double X, Flowmaster Outlaw and automatic. Drone is still fairly minimal with windows up few areas it's def noticeable But more times it's decent

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