Monstersonics

The premise was simple - go for a ride together, and assemble at a junction on a quite road and record the exhaust notes of our bikes. As it eventuated, 15 of the Sydney Oz Monster crew set off for a day's ride and "sound off" with all different Ducati models and exhausts, making it an excellent day out and some very interesting recordings.

For the uninitiated reader, to own a Ducati motorcycle means you are certain to have a passion for making noise with your machine, be it via the clutch, exhaust or both. There are recordings of bikes on the Internet, but none provide a proper comparison of how the real thing will sound, and the differences between all the choices.

So we assembled some recording gear, and went out to a quiet stretch of road, and setup pr recording system.Everyone went through the same routine - lined up their bikes to the recorder, started up, blipped the throttle a few times and then a little WOT, with the fuel injected bikes bouncing of their rev limiters.

The bikes assembled represented pretty much all monster models through the years, with the exception of the 600 engined bikes and the original S4R (desmoquattro). The rabble of Oz Monsters that assembled on the day included:

2 x M620's
1 x M750

1 x M800

2 x S2R800's
2 x M900's
3 X S2R1000's
1 x S4
1 X S4R Testastretta
3 x S4Rs Testastretta

And so, on to the bikes.

Pics courtesy of the official Oz Monster photographer, Mattyvas.

The Bikes

R_usty

Model: S4RS
Year: 2007
Pipe Manufacturer: Arrow
Pipe Composition: Titanium
Other: DP ECU, DP Open Airbox, Open Dry Clutch

Big T

Model: S4RT
Year: 2007
Pipe Manufacturer: Zard (NO Baffles)
Pipe Composition: Carbon Fibre
Other: DP ECU, DP Open Airbox, Open Dry Clutch

Bigiain

Model: M750
Year: 1999
Pipe Manufacturer: Staintune
Pipe Composition: Stainless
Other: No baffles, stock headers, chopped airbox lid, K&N air filter, FactoryPro jetkit. (Tired old 190,000km old motor)

Dockstrada

Model: S4RS
Year: 07
Pipe Manufacturer: Akrapovic
Pipe Model: evolution open 2-1
Pipe Composition: Titanium/carbon fiber
Other: DP ECU, DP Open Airbox, K/N filter, Open Dry Clutch

Andy1000

Model : S2R1000
Year : 2006
Pipe Manufacturer : ARROW
Pipe Composition : Carbon (full system , no baffles)
Other : 3/4 Carbon Clutch Cover , Open Air Box , DP ECU

MonsterDorf

Model: S2R800
Year: 2006
Pipe Manufacturer: Remus
Pipe Model: Revolution 2-1
Header: Spark
Pipe Composition: Titanium
Other: Std Airbox and filter, std ECU, baffle removed, wet clutch (so no open clutch cover), udder removed and replaced with spark header.

WhiteLion

Model: S2R 1000
Year: 2005
Pipe Manufacturer: Custom Headers/Termi Pipes
Pipe Composition: Carbon Fibre
Other: No baffles, K/N air filter, DP ECU, Open Clutch, PC3

Monstermick58

Model: 900M
Year: 1997
Pipe Manufacturer: Ducati Performance
Pipe Composition: Carbon Fibre end can, stock headers
Other: Std air box, Dynojet kit

Pigmy

Model: S4
Year: 2002
Pipe Manufacturer: generic el cheapo megaphones

MattyVas

Model: 620
Year: 2005
Pipe Manufacturer: MIVV GP Rounds
Pipe Composition: Carbon Fibre
Other: No baffles, Std AB filter and ECU

Ace70

Model: 900M
Year: 1995
Pipe Manufacturer: Ducati Performance
Pipe Composition: Conti Replica, Chromed, Baffles
Other: High Comps, Open air box with K&N and FCR's, Open clutch

Jukie

Model: 620ie
Year: 2002
Pipe Manufacturer: Stock/standard
Pipe Composition: Stock/standard

Betty

Model: S2R 800
Year: 2005
Pipe Manufacturer: Stock/standard
Pipe Composition: Stock/standard
Other: Stock/standard

Ducmonrob

Model: S2R1000
Year: 06
Pipe Manufacturer: Arrow
Pipe Model: Full race system
Pipe Composition: carbon fiber race
Other: Rapid 3, Open Airbox, K/N filter.

goldFiSh

Model: M800
Year: 2003
Pipe Manufacturer: Arrow
Pipe Composition: Titanium
Other: Std Airbox and filter, std ECU, baffles removed

The Results

And so the question that will invariably get asked: Who won the sound off?

Well, the answer is not all that clear. Don't get me wrong, yes we have a winner, butlike always there are alays wany different ways to interpret the results. To explain what I mean, I will need to get into a bit of audio geek speak.

How do we define loud in the "real world". Well first we record all of the bikes and then analyse the audio data. We could compare all the recording and choose the one which measured the largest peak level.

But that may not necessarily be the loudest bike perceived by our ears. We also to take into account time, or in other words the duration of the loudness and take that into account. So we need to look at average over time. In audio terms that is a measurement known as Leq or Longterm Equivalent Level.

Ok now to further complicate things, our ears sensitivity varies according to frequency. As it goes, our ears are most sensitive to the frequency band occupied by human speech (around 300Hz - 3000Hz) and are less sensitive to bass and high frequencies. The differences in sensitives also varies depending on how loud the sound source is.

A common way to measure audio level is by using a frequency response curve called A-Weighting which effectively filters out the low and high frequencies from the measurement. This was originally designed for use in soft sound sources, and thus is pretty useless in this application, but we will show it cause it's commonly used and available on your average sound pressure level meter. So we are going to look at Longterm Equivalent level, with an A Weighting filter applied, or Leq (A) in geek speak.

Anyway, you can google to your hearts content on all of this, so that's all I will say on the matter. What I am going to show is all three measurements for all bikes. Peak is pretty irrelevant, but cool to know, Leq and Leq (A) are very relevant. In this application, Leq will show arguably a truer representation, as it takes into account the low frequency rumble of the twins. Leq (A) is not as true, but most people can correlate it with a standard SPL meter.

Anyway, on to the results..... Given the above, I have ranked by Leq, but provide the other measurements for your comparison. Note the values are in dbFS (decibels relative to full scale on a digital recorder) to protect the innocent - they do not show real SPL!

And so the cheapo megaphones win! Congrats to pigmy for a bloody loud bike! Note there are a few surprises in there, and to be honest, the results are all damn close, and give the less than scientific approach we took in terms of how far away the recorder was to the pipes, any of the top bikes could be the real winner.

So where's the sound and video files? Alas I don't have a lot of time at the moment, so no time for video editing. In the mean time, enjoy the sound clips

Comparisons

OK, now onto the comparisons:

Stock Bikes
Stock M620 Jukie Green
Stock S2R800 Betty Purple

Note the similarities of the response, with two differing engines, a 620 and 800. Also note that the are the same (soft) level - no surprises here.

S2R800 - Stock vs Aftermarket
Stock S2R800 Betty Purple
S2R800 Remus 2-1 Monster Dorf Blue

So there's the obvious increase in level with the aftermarket pipes, but also note the change in shape - much more midrange coupled with all thar rumble. Note the 3 peaks ar 100Hz, 180Hz and 550 Hz. The three peak trend we will observe more later.

803cc Engined Bikes
Stock S2R800 Betty Purple
S2R800 Remus 2-1 Monster Dorf Blue
M800Sie Arrow Hi Ti goldFiSh Black

OK now three 800's, two with two very different aftermarket bikes. The blue is the Remus 2-1 system, wheres the black are my Arrow Ti's. Again generally the same shape (three peaks) with both (very different) aftermarket pipes. The lack of midrange of the arrows results in the lower rank of my bike.

1000DS Engined Bikes
S2R1000 Arrow CF Andy1000 Purple
S2R1000 Arrow CF Ducmonrob Blue
S2R1000 DP CF White Lion Lt Blue

Well take a look at the S2R1000's - 3 peaks again, but all in all a slightly different shape. As expected the two arrow bikes are very similar (note the extreme low end rumble - you can really hear that in the recordings with headphones), with the DP / Termi thingies of White Lion not too dissimilar

900 Carbies
M900 DP Lows Monstermick58 Green
M900 Conti, FCRS Ace 70 Pink

Carby Time - Two very differenet setups, with almost identical low freqnecy response. The higher frequencies is where the cont replicas start singing - again the recording and graphs correlate. Again, these engines have differing shapes to the others, but no matter what the aftermarket pipes, they seem really similar

Battle of the Carbs
M900 DP Lows Monstermick58 Green
M900 Conti, FCRS Ace 70 Pink
m750 Staintunes bigiain Brown

Adding Big's 750 carb into the mix shows the same engine based trend - the 750 is very different than the 900 carbs. It would have been good to have at lease two of the same engines of each type to confirm this, but the trend is starting to look solid.

Testastretta
S4Rs Arrow R_usty Yellow
S4RT Zard Big T Green
S4Rs Akroprovic Dockstrada Blue

Time for a little 4V action, which again shows the same trend. - Again, 3 very different excahust setups show a very similar response...... interesting.

620cc
M620 Stock Jukie Purple
M620 Mivv GP Mattyvas Brown

Those little shortly Mivvs do a great job of beefing up Matty's 620. Look at the differences between stock, in termsof both level and shape. For me it's a toss up between Ace 70's Contis and Matty's Mivvs in terms of the best sounding subjectively.

Battle of the 4V
Desmoquattro (S4) Pigmy Orange
Teatastretta (S4RT) Big T Green

So I couldn't leave the winner out of the comparisons! Here's pigmy's growling S4 against the S4R testa with the Zards.

Details

Ok the next section is really only included for the bike owners. I thought it would be cool to have frequency response graphs for all our bikes (yeah I need to find a life). At the same time, why not also include the Leq graphs for good measure! First chart is frequency response, second is Leq and peak SPL.

R_usty