Saturday, March 7, 2015

Garratt Sounds


I hope everyone is doing well.

Not a great deal has been happening on the modelling front lately. I have been fiddling around with an Ian Lindsay EHO kit which so far is coming up well. The filling of the roof was quite challenging, particularly getting the fillet shaped correctly. So far so good.

Regrettably I missed Thirlmere's steam fest this year. I would have loved to go however I made plans with a mate to attend the Avalon air show. The air show was good, some jets flew around making lots of noise and the stunt pilots put on great shows however it was an original Sopwith Camel that really impressed me. What a beautiful WW1 aircraft. It would have been a very hard aircraft to fly due to its large rotary engine, causing all sorts of gyroscopic precession issues (something that made the plane very manoeuvrable actually), but above all it's engine only ran at one speed - flat out. While flying, the engine is constantly cut so as not to over speed. It's quite strange, the engine was probably only powering the aircraft for half it's dog fight display flight. Very cool.

Here is a picture -

Fitting for 6029s big show last weekend and as the title eludes, I have been working on an AD60, ESU sound file. I recorded most of the sounds while in Canberra during 6029's photo shoot last winter. It's amazing what you can do with good quality recordings, unlike the battle I am having with the 57 class stuff I have. This project has pretty much been complete for some time now, however I have not had it installed in a locomotive.....until now.

I decided to test it out in my DJH model. The brass Garratt would allow for a better install however I have not painted my Mansfield version and don't know if I really want to. It will be a big job!

There are a few ways to achieve this install so as to create the sometimes out of sync exhaust beat. The expensive method would be to use two sound decoders and two speakers. At $190 a decoder, along with two power packs and two speakers, I think this method is just too expensive. It would sound great though!

The avenue I took was to use one ESU Loksound micro decoder, one Zimo 15mm x 11mm x 12mm sugar cube speaker, two ESU power packs and a Lokpilot V4 micro (non-sound) decoder. While still an expensive install, the original value of the locomotive needs to be considered I guess.

On the subject of speakers, I have found the genuine Zimo SC speakers tend to out perform the generic Knowles type speakers being sold everywhere. I don't know if this is because the Zimo is supplied with a fitted enclosure, keeping the very sensitive speaker cone protected or if the speaker is in fact manufactured by a different company? I have never had a Zimo speaker crackle or distort with volume where as I have found the Knowles types to be very unreliable. Just my observations. I would love to hear from others.

Anyway back to the DJH AD60 install hey. I fitted the sound decoder, with power pack into the front engine unit. A pair of wires run, via a two pin connector to the Zimo speaker located in the boiler section ash pan. The sound quality from the taller sugar cube is quite impressive. I am still waiting for my Lokpilot (non-sound) decoder to arrive, so at this point the back engine does not run. When it does turn up, it and it's power pack will be installed and the locomotive will hopefully be able to move its self.

Loksound Micro and ESU Power Pack

You may ask (well you may not ha ha) how will one decoder give an out of sync beat? The answer is ESU magic. I was playing around one day and found a setting for articulated locomotives. If you add another drive sequence into the second sound slot, you can set the decoder up to play the second drive sound with an adjustable delay. The positives to this set up are that it can all be set up with one decoder however one negative is the repeated in and out of sync sound. I can live with the repeatability and now that I think about it, would most likely happen with a two decoder set up anyway.

The project is set up using the throttle type sound manipulation which I talked about in previous posts. I am starting to like this control method as it allows you to control the engines chuff intensity simply with small throttle changes. Much like driving the real thing I guess.

I still need to level out the different compressor profile volumes and load the stoker sound files but hope the included video gives you some idea as to where I am at with it.

Sorry for the not so good audio quality. I still don't know how to turn off the automatic volume gain setting on my video camera. It tends to level out the overall volume unfortunately even with the Rode mic attached.

That's it for now. Have to get back to my Auscision 45 class and work out how to separate the damn lights.



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