737 engine sound differences

[alex94]

What’s the difference in acoustics amongst the classic 737 aircraft? And will the 3c be developed at a later date Benoit?

kind regards
alex

[aerofoto - HJG Admin]

****EDIT/CLARIFICATION 21/12/17****

This's likely too complicated for most (other than the very best audio compilers) to understand .... BUT .... there's differences within the FDE for each of our 3 basic B737 types that impact sound .... and which dictated what we needed to do in regard to providing audio that sounds similar, if not uniform, for use with all 3. This couldn't be achieved using a single soundpack for everything

For e.g (to try'n explain things simply) .... the B737-300 soundpack can't produce quite the same audio playback within the power range if used with either our B737-400 or -500 .... and vice versa too. It'll function .... but .... not in accordance with how "we want it to work".

Whilst the end result (what the end user hears) for each of these 3 B737 soundpacks may appear similar, if not identical, "it's the FDE stated variations and slightly different audio coding within each soundpack which enables this" .... hence our need to produce 3 separate soundpacks each of which is "aircraft type specific"

BUT .... there's a bit more to all this since too since we're not slap happy and prefer doing things "PROPERLY" ....

The external audio for each soundpack will appear identical (as it should) .... BUT .... the internal audio (in particular) is adapted to take into consideration "wing/engine to flight deck distances" as this applies in regard to each of the different aircraft lengths (which dictates the "proportion" of what may be heard) .... by the "increasing or subtly masking" the volume of certain interior engine related sound details and clever use of wind/environmental friction audio also. The interior aspect of each of these "NEW" soundpacks is where the obvious differences have been applied .... given this aspect of each soundpack is compiled on the basis of a flight deck (not PAX cabin) perspective.

I hope this additional clarification (now I have the time to try and explain it) helps people understand there's "A HELL OF A LOT MORE" that goes into any audio production than actually meets the eye

What the end user actually hears at the end of the day will always be governed by their own FS sound slider positions/preferences though .... if not the capability of their audio hardware too .... if not both .... so .... follow Benoit's recommended audio settings (to start with) and then adjust the FS sound sliders in accordance with personal preference/s.

We won't be doing the -3C. There's absolutely no point .... given there's no (obvious) external tonal differences between it and what's already represented for the appropriate aircraft type/s.

What Benoit's provided is "THE BEST/MOST AUTHENTIC CFM-56 audio set currently available for FS .... and for the B737-300/400/500 series in particular .... but which only function as intended if used with the HJG provided FDE for these simulations. These new soundpacks won't function as intended if used with other B737-300/400/500 FDE suites.

Mark C
AKL/NZ

[alex94]

Thanks mark for that detailed bit for info regarding the sounds

[aerofoto - HJG Admin]

I note this isn't the first time you've raised the subject of engine sub type designations in relation to FS audio.

PLEASE NOTE: A different engine sub type designation .... partiularly in regard to its suffix .... more often than not indicates a thrust or other performance parameter variation .... but .... doesn't necessarily imply any tonal difference.

Among the simultions so far represented by HJG .... "IF" specific engine audio differences are required then we generally offer these .... and if we're don't offer them then they're not necessary

The only exceptions to the above rule among HJG's entire FS audio library are those soundpacks for both the "B717-200" and "DC-9-30 REFAN" .... both of which are "TEMPORARY AUDIO ONLY" and until further notice.

ALSO AND WHILST ON THIS SUBJECT ....

I also note for some reason our temporary B717-200 audio appears to have been rebranded "RR BR-715" .... but .... which is precisely what it's not. And I've also similarly noted our current DC-9 soundpacks appear to have been labelled "FSX compatible" too .... which they're not (they're FS2004 compatible only) .... so .... we'll need to get these details corrected to avoid folk being misled.

Mark C
AKL/NZ

[alex94]

I only asked about these sounds as i know with the A, B and C variant of the cfm56-5 series engine have slight acoustic differences and i thought that the C model for the 737 engine might be made maybe due to this factor

[aerofoto - HJG Admin]

the A, B and C variant of the cfm56-5 series

The CFM-56-5 series is primarily an AIRBUS type powerplant though .... different guts + cowl shape/s = different ecoustics.

Each of our B737's are based on the -3B series .... a little different from the above .... and a little different again from the -7B series that powers the B737 NG's that followed the -300/400/500 into service.

My above statement though (in regard to engine type suffixes not always implying any obvious external tonal difference) was in regard to powerplants among the B737-300/400/500 series we represent .... and not anything else

Mark C
AKL/NZ

[alex94]

Yeah no that’s omah mark. I was just mentioning those as a comparison amongst the different series of the same engine 🙂

[Benoit - HJG]

Dec 7, 2017 14:10:27 GMT alex94 said:

What’s the difference in acoustics amongst the classic 737 aircraft? And will the 3c be developed at a later date Benoit?

Alex94

I have no plans on making a 3C soundpack.

My understanding of aircraft engine manufacturers and their numbering system, suffixes/sub-suffixes does relate to differences in engines thrust, weather it be uprated or derated.

I believe that sounds and acoustical differences come from a myriad of differentials such as number of fan blades used, low/high pressure turbine/compressor stages, nacelle intake and exhaust thrust and so on.

The way in which I put together soundpacks come from real aircraft sound recordings widely available, I always try and reproduce what I hear in trying to make the simulation as realistic as possible, always working around within the flight simulator software sound limitations.
The soundpacks which I released for this project represents the CFM56-3 produced for B737-300/-400-/500 series in general for external views, I went little more specific with the internal views for each of the 737 models according to body/fuselage length and in relation from a point of view of the flight deck to the location of the engines in distance in a way of sound volume levels.

Benoit

[alex94]

Understood guys. Your sounds never cease to amaze Benoit. I have to say you’re one of the best in this field 🙂

[darrenvox]

I never understand the -xxx numbers after cfm56, for me it's not a big thing as I don't notice much of a difference

[aerofoto - HJG Admin]

"IF" one doesn't recognize/understand the significance of the different engine sub marques (normally at the suffix) that apply to any aircraft engine type name .... then .... it pays not to try'n do so, but rather, just "take our word for it" when we say there's differences (some major) because "there are" in fact

HOWEVER .... it's these engine type sub marques which define the certified thrust rating and/or other performance capabilities of any engine type .... not all of which are repliicable in FS though and which is generally restricted to just engine thrust and F/F.

Like applies to aircraft engines .... sub marques also similarly apply among aircraft types as well .... for e.g. B737-100/-200/300/-400/-500/-600/-700/-800/-900 .... and again they're "ALL" different .... just as the various engine sub marques are diffeent too.

RW sound is "synthetic"/can be influenced by surrounding ambient conditions .... along with the like of what's already been stated among earlier replies within this thread

I don't notice much of a difference

There "ARE" differences among each of these 3 soundpacks.

Whilst they may sound similar .... it's the less obvious (unknown to the majority) but entirely necessary coding within each soundpack that ensures this .... BUT .... there's also a number of other obvious, although subtle, treatments that've been applied, by necessity, too and in the interest of producing highly quality and authentic results for each one .... and now I've time to do so (my FS work for the year being essentially finished) I've just "clarified/edited", but haven't otherwise changed, my first reply posting within this thread in order to try'n elaborate on these details .... and how it all applies to this B737 audio .... among that provided for some of our other simulations too.

There's "ALWAYS" a good reason why we do what we do (despite most not understanding or even being aware of it) .... or .... we simply wouldn't do it

Mark C
AKL/NZ

[darrenvox]

I wasn't meaning about the sound packs just the real world sounds or engine types..

[aerofoto - HJG Admin]

I think I (sort of) addressed that for you .... per the first part of my last reply

As for the rest .... that's "bonus information" given the original purpose of this particular thread.

A good business policy (although HJG isn't a business) .... in my mind (at least .... and certainly a policy I've always applied to my own professional business undertakings of the past almost 40 years .... and which is by now instilled within me) is to, where possible, provide "a little more" than people might expect/request .... and since in a forum sense I like to think that benefits more (other) people than might ever ask any particular question .... and before they even ask it

Mark C
AKL/NZ