2-6-6-2 Mallet Sound

[littletone]

Hi All,
I?ve just added a second wheel sensor to my SV Mallet connected to a Massoth XLS.
Not ever hearing a Mallet in rear life, I assumed that it would sound like 2 coupled loco?s, BUT it sounds as if its twice as fast as a standard loco, if you get my drift!
So is that right.
I found this on you tube, it a 2-6-6-2 and it too sounds twice as fast.
http://www.youtube.com/watch?v=qdtJv5z17hU

 

[Tony]

sounds ok to me but i do know i want one
Tony

 

[steve parberry]

Are you sure you need two sensors as that will give you double the amount of pulses to the sound decoder. As far as i know most decoders are recorded and set up to play of one pulse generator.

 

[stockers]

Because a mallet is compond, you only get four exhausts per wheel revolution, not 8. This is the same as most two cylinder locos.
The result of compounding is a more muffled exhaust beat as the pressure is lower at the blast pipe. This muffling also means that each blast is less distinct as it merges with the previous and next ones.
If you listem carefully to that sound track in the video you will hear the exhaust almost as a background sound - most of the sounds are coming from the motion - which does sound like two engines, because basically it is.

 

[stockers]

Are you sure you need two sensors as that will give you double the amount of pulses to the sound decoder. As far as i know most decoders are recorded and set up to play of one pulse generator.

The XLS is built to accept two wheel sensors. When/if a mallet (or other twin loco) is running in non-compound form (full pressure to all cylinders for more power) each truck can get out of phase with each other which sound kind of odd but interesting. The Ffestiniog Fairlies are good at this as they are not compounded.

 

[New Haven Neil]

Spot on Alan. I have some recordings of Norfolk & Western class A 'mallets' (they aren't true mallets as they are simple expansion, not compound) and the two engines go in and out of synchronisation, making a wonderful sound, sometimes with 8 beats, sometimes 4, and in between a syncopation of jazz music!

 

[littletone]

Thanks for the replies,

So do I remove the second wheel sensor?

 

[stockers]

No. You should get the in and out of sync sounds as refered to above.
I have never heard this on a model - I hope it works well for you. If so, we need to hear it

 

[littletone]

I cannot hear the 2 engines going out of beat. Just, what sounds like 2x the speed sound. When I remove the front wheel sensor from the XLS, it goes back to the normal sound which is in-sync with the motion of the rear pistons.

So, am I after 2 separate sounds, one from each motor block?

If so, would fitting a speaker in the front and connecting a new Massoth S decoder to just run the steam sound on the front, leave the XLS to run both motor block and the sound on the rear and the lights/functions.

 

[ntpntpntp]

Maybe you're simply lucky in having two motor blocks that run almost precisely the same speed, and the sensors just happen to be out step with each other most of the time?

What happens if you apply a little hand-pressure to one of the sets of wheels to slow it down in relatiion to the other block - do you get different chuff rates that go in-an-out of sync then?

 

[littletone]

Maybe you're simply lucky in having two motor blocks that run almost precisely the same speed, and the sensors just happen to be out step with each other most of the time?

What happens if you apply a little hand-pressure to one of the sets of wheels to slow it down in relatiion to the other block - do you get different chuff rates that go in-an-out of sync then?

Thanks for the advice,
After extensive testing, I think I?m going to stick with the 2 sensors on the XLS.
I?ve done a short video, But how do you up load 66mb to the forum?

 

[ntpntpntp]

I think most folk upload to youtube then post a link here.

 

[littletone]

I think most folk upload to youtube then post a link here.

Just signed up to you tube..........

http://www.youtube.com/watch?v=cMIT7CDPW98

 

[ntpntpntp]

interesting! I can see the two blocks are running at slightly different speeds and going into sync by the end of the clip, and you do seem to be getting 4 chuffs per wheel revolution which sounds good, though whether each block's sensor is giving 4 chuffs or 2 is difficult to tell?

Anyway, sounds ok to me!

 

[beavercreek]

Sounds the way it should be Alan. On most sound boards you can adjust the 'syncopation' for malletts when using just the two wheel sensors (or one).

 

[littletone]

Just fitted a massoth emotion S decoder to run the sound on the front Drivers, put the speaker in the smoke box (perfect fit).
I wanted to be able to program both decoders separately, so I installed a DPDT switch in the firebox with an LGB 2 pin socket for the S.


http://www.youtube.com/watch?v=0mUFZ28WML8

 

[Zerogee]

Lovely sound, Tony! Having the two sound decoders really works well.