What is "drone" ???

GammaZeta · 06-30-2012, 08:05 PM

As a new Z4M member looking to buy an aftermarket exhaust, I keep reading about "drone". Can someone explain to me what drone is, what it sounds like, how it affects your hearing, etc.?

DataStream18 · 06-30-2012, 09:47 PM

Just what the name sounds like when you say it. Elongate the word when you say it, meaning stretch the word out. Its annoying to some but other it doesnt bother em'.

GammaZeta · 06-30-2012, 10:10 PM

I'm familiar with the definition, but when applied to the Z4M. Is it a constant noise? Or does it only happen in a certain gear or rpm?

seank · 06-30-2012, 11:33 PM

I believe it only applies to certain rpms. If it's all the time, they just call it LOUD. It is usually loudest at the power band or just before.

I also had never heard of this before I came to this site.

pokeybritches · 07-01-2012, 12:04 AM

It's not synonymous with "resonate" but it's close. If an exhaust drones, it constantly makes noise, usually when you don't want to. It's a descriptor for undesired noise on the highway at lower rpm. It's the opposite of quiet cruising. There's not an exact sound that is drone. Diablo drone is different from Magnaflow drone, which are both different from RPI drone.

Certain frequencies will resonate through an exhaust at specific rpm. Others will be canceled out. The exhaust can be designed to enhance or minimize particular frequencies. With testing, one could figure out which frequencies are considered desirable and which are not, and then design the muffler to cancel the unwanted frequencies. However, as the engine moves up in rpm the frequencies emitted change. The muffler that canceled a 40 Hz wave may allow a 60 Hz wave to be amplified... so now the muffler that was tolerable at 2000 rpm may be obnoxious at 2500 rpm. If you want an exhaust that is quiet during cruising, you give up some song at the high rpm.

Then there are octaves and resonating frequencies for the vehicle itself... but honestly, I'd expect most muffler companies to make one good design and adapt it to all models with minimal changes. They probably bolt it up to make sure it doesn't sound like crap, make some tweaks, and then call it good. This is just me guessing though, because it's fiscally impractical to pump out more than a few prototypes.

I'd assume Shipkiller knows quite a bit more than I do about wave propagation

.

06-30-2012, 08:05 PM	#1
GammaZeta Captain 59 Rep 862 Posts Drives: 1 Join Date: Jun 2011 Location: Ma iTrader: (1)	What is "drone" ??? As a new Z4M member looking to buy an aftermarket exhaust, I keep reading about "drone". Can someone explain to me what drone is, what it sounds like, how it affects your hearing, etc.?
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06-30-2012, 09:47 PM	#2
DataStream18 Lieutenant 45 Rep 556 Posts Drives: 2003 ESS TS1 Z4 Join Date: May 2011 Location: Muskegon, Mi iTrader: (0) Garage List 2004 ESS Supercharg ... [4.00]	Just what the name sounds like when you say it. Elongate the word when you say it, meaning stretch the word out. Its annoying to some but other it doesnt bother em'. __________________ TS2/Cat-Less Headers/Jet Hot Coating 2000/CF Engine covers & Oil Cap/RPi Scoop/Matte Black Grills/H&R Sport Springs/15mm Spacers Rear/12mm Spacers Front/Flowmaster 40 series/Alcantara Shift Boot/CF Vinyl wrap/SPEC Stage 2+ clutch/8 Lbs Fly wheel/ZHP Shift knob/Hawk HPS Pads/Cross Drilled/Slotted Rotors/Performance Pedal Set/Stewart water pump Love is like a fart; if you have to force it, it's probably shit.
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06-30-2012, 10:10 PM	#3
GammaZeta Captain 59 Rep 862 Posts Drives: 1 Join Date: Jun 2011 Location: Ma iTrader: (1)	I'm familiar with the definition, but when applied to the Z4M. Is it a constant noise? Or does it only happen in a certain gear or rpm?
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06-30-2012, 11:33 PM	#4
seank enthusiast 48 Rep 1,695 Posts Drives: e30 m3,e90 wagon,sprinter,z4m Join Date: Dec 2011 Location: sacramento, ca iTrader: (4)	I believe it only applies to certain rpms. If it's all the time, they just call it LOUD. It is usually loudest at the power band or just before. I also had never heard of this before I came to this site.
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07-01-2012, 12:04 AM	#5
pokeybritches Colonel 479 Rep 2,782 Posts Drives: ESS/G-Power Z4M, VF Z4, 996tt Join Date: Sep 2009 Location: Los Angeles iTrader: (12) Garage List 2006 BMW Z4M [10.00] 2006 BMW Z4M [8.50] 2003 BMW Z4 3.0i [9.00]	It's not synonymous with "resonate" but it's close. If an exhaust drones, it constantly makes noise, usually when you don't want to. It's a descriptor for undesired noise on the highway at lower rpm. It's the opposite of quiet cruising. There's not an exact sound that is drone. Diablo drone is different from Magnaflow drone, which are both different from RPI drone. Certain frequencies will resonate through an exhaust at specific rpm. Others will be canceled out. The exhaust can be designed to enhance or minimize particular frequencies. With testing, one could figure out which frequencies are considered desirable and which are not, and then design the muffler to cancel the unwanted frequencies. However, as the engine moves up in rpm the frequencies emitted change. The muffler that canceled a 40 Hz wave may allow a 60 Hz wave to be amplified... so now the muffler that was tolerable at 2000 rpm may be obnoxious at 2500 rpm. If you want an exhaust that is quiet during cruising, you give up some song at the high rpm. Then there are octaves and resonating frequencies for the vehicle itself... but honestly, I'd expect most muffler companies to make one good design and adapt it to all models with minimal changes. They probably bolt it up to make sure it doesn't sound like crap, make some tweaks, and then call it good. This is just me guessing though, because it's fiscally impractical to pump out more than a few prototypes. I'd assume Shipkiller knows quite a bit more than I do about wave propagation . __________________ VF Engineering Z4 3.0i, ESS Z4M, G-Power Z4M, 996 Turbo
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