Baby GM double header compatibility question

[Sean]

Simple but interesting question today for the group.

 

I see according to wikipedia we had the 567 and the 465 in service at the same time across the baby GM classes and as we all know double heading members of these classes was also a very common sight here in Ireland.

my big question is simply, did matching the engine types matter at all or would it have been a common occurrence to hear the 567 and 645 running in consist on these trains?

[Blaine]

The 645 idles and redlines slightly higher so theres a different sound which is noticeable especially on idle when 2 are together, its not been heard for a long time though, when 141/2 had their run to Longford and back....

[Noel]

On 12/3/2023 at 1:06 AM, Sean said:

Simple but interesting question today for the group.

 

I see according to wikipedia we had the 567 and the 465 in service at the same time across the baby GM classes and as we all know double heading members of these classes was also a very common sight here in Ireland.

my big question is simply, did matching the engine types matter at all or would it have been a common occurrence to hear the 567 and 645 running in consist on these trains?

As far as I know they were not always matched in service, hence running a 141 with a 181 class in consist is normal. For DCC sound models, recommend sound only on one of the locos, and that the decoders be the same type with the same sound projects, and same motor CV settings (eg two Lenz Silver+, or two LokSound V4, or Lovsound V4 with a LokPilot V4.

[connollystn]

Think it was mentioned on here some years ago that some of the 141 class locomotives had their engines (567) replaced with those from the scrapped C201 locomotives so it's likely that 141/181 double headed locomotives sounded the same in the IR/IÉ era. 

[Noel]

For those who choose to operate sound on both model locomotives, WheelTappers offer 3 variations of each of the 567 and 645 prime movers (ie slight change in pitch) so the two locos do not sound the same if both 567 or 645.

Personally I only operate one loco with sound at a time on my layout because 2 (or worse 3) sound locos running at the same time, sounds just an awful confused cacophony of irritating noise. They blur into each other, but that's just my personal experience. It's impossible to simulate the classic doppler effect as a train approaches and passes a scene using an onboard speaker. Don't get me wrong I love DCC sound especially 567 and 645, but don't like when it sounds like a group of wasps stuck in a jam jar screeching to get out like the 071 or 201 primer movers.

[jhb171achill]

"............a group of wasps stuck in a jam jar............."

 

 

Edited March 13, 2023 by jhb171achill

[Sean]

11 hours ago, connollystn said:

Think it was mentioned on here some years ago that some of the 141 class locomotives had their engines (567) replaced with those from the scrapped C201 locomotives so it's likely that 141/181 double headed locomotives sounded the same in the IR/IÉ era. 

as far as i understand it theres a little more to it than this. only a select few units initially got the whole 645 transplant whereas later the entire fleet was fitted out with 645 cylinders and liners for parts standardisation, the latter fitout would not really have changed the overall sound of things as it was still mostly a 567 motor with the same power output so it kept that characteristic 567 sound.

 

I also see reports of at least 181 getting a 567 sp i think by the end there was a good mixture of engines and sounds in service together, open to correction on that though.

7 hours ago, Noel said:

For those who choose to operate sound on both model locomotives, WheelTappers offer 3 variations of each of the 567 and 645 prime movers (ie slight change in pitch) so the two locos do not sound the same if both 567 or 645.

Personally I only operate one loco with sound at a time on my layout because 2 (or worse 3) sound locos running at the same time, sounds just an awful confused cacophony of irritating noise. They blur into each other, but that's just my personal experience. It's impossible to simulate the classic doppler effect as a train approaches and passes a scene using an onboard speaker. Don't get me wrong I love DCC sound especially 567 and 645, but don't like when it sounds like a group of wasps stuck in a jam jar screeching to get out like the 071 or 201 primer movers.

ive actually gotten two MM 567 chips that i assume are from different batches and they both contain 2 completely different prime mover recordings. so its proving useful for experimentation.

ive been messing around with both sound decoders as well as watching videos from yourself and others and i have been taking notes of why people dont like running 2 sound chips together and ways that could be improved on including old suggestions from legoman on RMweb for getting nice sound into 2 consisted locos.

I definitely get what your saying about all the sounds melding together into one big mess but i really do think this can be overcome with a little tuning of CV's as there are videos of american locos with 2 prime movers onboard and running independantly on a single loksound and these sound quite good. not sure if these locos are fitted out with multiple speakers or not but theres only one audio out on the loksound as far as i know so all speakers would be playing the exact same sound. they even have the response from the movers delayed different amounts at throttle change so you dont hear that weird resonance when they both notch down to idle at the exact same rpm/time

Funnily enough that you mention the doppler effect, I definitely am hearing one when i run a train around although because im in a box room running around a 6x4 loop even when the loco is furthest from where i am sitting the prime mover is still unrealistically loud to me and i really have to listen out for it. the microphone on my phones camera really does not like the volume either, despite neither of them overpowering my ears when listened to.

 

I actually think all of these issues are intrinsicly linked and can be solved. going down the rabbit hole tonight, will report back.

Edited March 13, 2023 by Sean

[Sean]

As i was saying earlier. i think these things are just a bit too loud for my size of room, after all you can hear the sounds of engine tickover over the sound of people talking at a busy exhibition hall, so the speakers are capable of spreading their sound over a particularly large radius which all in all is only a good thing.

So i started messing with my master volume CV and settled on a baseline of around 70 for each loco (default is 192) definitely suiting the room better now and im more spatially aware of where a loco is and they sound distant when they are at the other side of the room.

BUT

when i fired up three chips together the sounds didn't all sing together and there seemed to be decent separation between all of the speakers. noticed a big difference in the 2 sounds when locos are coupled up and with decoder pro open on program on main I was able to tweak the volume of these 2 locos on the fly and it allowed me to set up a nice and balanced mix between the two locomotives.

This definitely merits further investigation, however that can be for another night, i need more loksounds 

[Noel]

@Sean you are correct. The default volume on most sound projects is far too high. I generally reduce the volume by half on my locos and they are plenty loud enough. The MM sound projects have excessively loud default out of the box volume level, sometimes leading to speaker distortion (eg 121, 071).