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Noel

Fitting Enhanced Bass Relex speaker - MM 141/181

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Posted (edited)

Ok so far I have fitted DCC sound to a few Murphy Model 141/181s by installing a basic speaker in the speaker cradle provided inside the MM loco body. Really quick and easy to do all that was required was to lift off the loco body, solder the two speaker wires to the locos circuit board PCB at SP+ and SP-, plug a 21 pin sound decoder in (LokSound or Zimo), put the body back on and go. About 10-15 mins work and no cutting.

 

However I decided to try a DC Kits supplied LokSound decoder with baby GM recording but with an enhanced bass reflex speaker. As the speaker is in an enclosed rectangular box it would not fit in the speaker cradle of an MM 141/181 nor even inside the Loco body with out some cutting and fettling to get it to fit in. It took me about 90 minutes as I was being careful to measure and weigh up options. A lot of work compared to dropping a basic speaker in the MM cradle.

 

http://www.dckits-devideos.co.uk/shop/dcc_digital_loco_sounds/irish_diesel_loco_sounds/class_141_gm_bo_bo_dc_kits_.php

 

  1. Take loco body off (leave walkway side rails in place)
  2. Remove the supplied plastic speaker cradle - 2 screws
  3. Cut the two metal lugs off the metal chassis top that received the cradle screws (disc cutter)
  4. Cut away a raised section of the metal chassis just in front of the PCB (disc cutter)
  5. Cut away a small section off the underside end of the bass reflex speaker box (doesn't effect sound quality). The alternative to this is to cut a few millimetres off the end of the circuit board, but I decided not to bodge the loco anymore than I had to. (saw + knife)
  6. Remove the beige plastic support under the loco body roof grill - 2 screws (this obstructs the speaker box)
  7. Cut and file away the plastic lug on the inside of the loco body roof that received the rear most screw from above
  8. Plug the decoder in (which is prewired to the speaker) and place speaker box over the area where the cradle used to be with the cut away bit overlapping the circuit board
  9. Put the body carefully back on and pop the walkway rail ends back into both cab sides.

Ok, got it done and it sounds great, but to be honest I won't bother again with all the hassle to fit a bass reflex speaker. In future I will instead just remove the beige plastic support from under the roof top grill which will let a lot more sound out of a standard cradled speaker. I didn't like bodging these lovely locos. :)

 

IMG_0606.jpg

 

IMG_0605.jpg

 

IMG_0607.jpg

 

I will post more on the sound quality and DCC operation later perhaps with a video clip. In summary, it sounds better than the Zimo with standard speaker, but doesn't drive as well (i.e. sound not mirroring throttle inputs quite as well). Ah well can't have everything. :)

 

Overall though it is very good and the best sounding baby GM engine I've heard so far.

 

PS: I would love to hear this recording in the future with the new LokSound 'Full Throttle' decoders because I suspect the drive and notching would sound and behave more realistic.

 

PS2: I really liked the F3 long horn and F8 distant horn sounds, but the F2 short horn sounds awfully weak.

Edited by Noel

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Video clip of DC-Kits (Legomanbiffo) LokSound v4 DCC sound chip with enhanced bass reflex speaker in Murphy Model 190 - 181 class. The clip was rather rushed, if I get some time next week I'll try and record some shunting operations and starting off with a heavy train. As I said in 1st post I'm not convinced the good sound quality is due to the bass reflex speaker and even if it is slightly better I wont be bothering to cut any more MMs to fit them.

 

http://www.dckits-devideos.co.uk/shop/dcc_digital_loco_sounds/irish_diesel_loco_sounds/class_181_gm_bo_bo_dc_kits_.php

http://www.dckits-devideos.co.uk/shop/dcc_digital_loco_sounds/irish_diesel_loco_sounds/class_141_gm_bo_bo_dc_kits_.php

 

[video=youtube;QSAU1iYOg-w]

 

We are spoiled for choice with sound on baby GMs, two LokSound options and one Zimo, and shortly a third LokSound option when 'Full Throttle' becomes available to match or possibly even exceed Zimo's superb 'Real Drive'. Happy Days for sound enthusiasts. I'll post this video clip to the layout thread in a few days.

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Do you know who's doing the 'full throttle' version? That sounds like fun.....!

 

Richard.

 

As far as I know DC Kits (courtesy of Legomambiffo) can supply them with the Full Throttle features, but you would need to contact them as they only list UK sounds with those features.

Otherwise you can download the files from ESU yourself and programme your own Loksound decoders if you get the Lokprogrammer.

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Do you know who's doing the 'full throttle' version? That sounds like fun.....!

 

Richard.

 

Hi Richard, it is available for most of ESU's USA locos right now, but I don't know if or when MM might supply 'Full Throttle' versions of their existing LokSound chips for 071, 201. I see DC-Kits have announced 'DRIVELOCK' which I presume is their name for 'Full Throttle' on ESU LokSound diesel chips, but I don't know when they plan to re-release 141/181 chips with this software upgrade feature added. I've emailed Charlie Petty to ask. Noel

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Nice job Noel. I never had the cajones to cut up any of my 141's so I settled for the drop in speaker option!

It sounds good but like you said I don't think it justifies the work involved.

 

On a slightly pedantic note: that particular GM engine sound is the EMD 567 which was fitted to the 141's and 121's so it isn't prototypical for a 181 which were fitted with the EMD 645.

There is a 645 sound file available from ESU.

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Ok so far I have fitted DCC sound to a few Murphy Model 141/181s by installing a basic speaker in the speaker cradle provided inside the MM loco body. Really quick and easy to do all that was required was to lift off the loco body, solder the two speaker wires to the locos circuit board PCB at SP+ and SP-, plug a 21 pin sound decoder in (LokSound or Zimo), put the body back on and go. About 10-15 mins work and no cutting.

 

However I decided to try a DC Kits supplied LokSound decoder with baby GM recording but with an enhanced bass reflex speaker. As the speaker is in an enclosed rectangular box it would not fit in the speaker cradle of an MM 141/181 nor even inside the Loco body with out some cutting and fettling to get it to fit in. It took me about 90 minutes as I was being careful to measure and weigh up options. A lot of work compared to dropping a basic speaker in the MM cradle.

 

http://www.dckits-devideos.co.uk/shop/dcc_digital_loco_sounds/irish_diesel_loco_sounds/class_141_gm_bo_bo_dc_kits_.php

 

  1. Take loco body off (leave walkway side rails in place)
  2. Remove the supplied plastic speaker cradle - 2 screws
  3. Cut the two metal lugs off the metal chassis top that received the cradle screws
  4. Cut away a raised section of the metal chassis just in front of the PCB
  5. Cut away a small section off the underside end of the bass reflex speaker box (doesn't effect sound quality). The alternative to this is to cut a few millimetres off the end of the circuit board, but I decided not to bodge the loco anymore than I had to.
  6. Remove the beige plastic support under the loco body roof grill - 2 screws (this obstructs the speaker box)
  7. Cut and file away the plastic lug on the inside of the loco body roof that received the rear most screw from above
  8. Plug the decoder in (which is prewired to the speaker) and place speaker box over the area where the cradle used to be with the cut away bit overlapping the circuit board
  9. Put the body carefully back on and pop the walkway rail ends back into both cab sides.

Ok, got it done and it sounds great, but to be honest I won't bother again with all the hassle to fit a bass reflex speaker. In future I will instead just remove the beige plastic support from under the roof top grill which will let a lot more sound out of a standard cradled speaker. I didn't like bodging these lovely locos. :)

 

IMG_0606.jpg

 

IMG_0605.jpg

 

IMG_0607.jpg

 

I will post more on the sound quality and DCC operation later perhaps with a video clip. In summary, it sounds better than the Zimo with standard speaker, but doesn't drive as well (i.e. sound not mirroring throttle inputs quite as well). Ah well can't have everything. :)

 

Overall though it is very good and the best sounding baby GM engine I've heard so far.

 

PS: I would love to hear this recording in the future with the new LokSound 'Full Throttle' decoders because I suspect the drive and notching would sound and behave more realistic.

 

PS2: I really liked the #2 long horn and #3 distant horn sounds, but the #1 short horn sounds awfully weak.

 

Thanks for the info Noel.

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Nice work Noel. Did you seal the speaker back up after cutting it back?

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Posted (edited)
Nice job Noel. I never had the cajones to cut up any of my 141's so I settled for the drop in speaker option!

It sounds good but like you said I don't think it justifies the work involved.

 

Thanks IT. :) I agree its not worth the work. With hindsight I should have followed your advice here DCC sound speaker comparison and just taken the back off the speaker box so it could drop in like yours. I will use the supplied speaker cradle in future and just remove the unnecessary plastic strip under the metal roof grill in future.

 

BTW I just did the ESU CV54=0 + F1 motor calibration and it now drives better.

 

On a slightly pedantic note: that particular GM engine sound is the EMD 567 which was fitted to the 141's and 121's so it isn't prototypical for a 181 which were fitted with the EMD 645. There is a 645 sound file available from ESU.

 

Correct, yes thanks, I ordered the 141 chip, but decided to drop it into 190 instead of another 141 I have which is pending renumbering to 142.

 

Nice work Noel. Did you seal the speaker back up after cutting it back?

 

Hi Dave, no I didn't bother. I think the factor that has improved the speaker performance more than anything is removing the little sheet of plastic that is screwed in under the 141/181 roof grill, rather than the speaker type. It lets the sound out of the body.

 

One really quirky little feature of the sound project is what happens when you change direction on your DCC cab. Believe it or not, it actually plays the sound of the driver opening the door of the cab, with foot steps as he walks along the walk way, opens and closes the door of the other cab. Interesting the 1st time but a real PITA because you can't drive until this little walkabout sequence has completed, so shunting is awkward. So I switched it off by setting F23/F24 to on (i.e. so when you change direction, you can drive immediately without delay). I love the sound of the EMD with this project and the long and distant horns F3 and F8. The distant horn simulates a doppler effect which is very impressive. However the short horn F2 sounds like it has a potato blocking it! The flange squeal is a bit loud but when I get a chance I will set its own individual volume lower.

 

PS: Personally I find default volume on the LokSound chip set way too high and I usually reduce it by half.

 

Thanks for the info Noel.

 

Your welcome :) Hope its of use

 

EDIT: Video clip added with demo of 'Legomanbiffo' DCC sound on 181 class (same clip as on Kingsbridge thread)

Edited by Noel

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Played with 190 and the 'Legomanbiffo' LokSound at lunch time and have to say I am impressed with the loco sound. Figured out shunting mode and how to turn the cab change sound sequence off (i.e. cab doors opening, foot steps down the walkway as driver changes ends).

 

The sound levels of some of the channels need adjustment, the station announcement is too quiet, but the flange sequel is louder than a 737 doing a gear up landing on asphalt. :) Will try this chip with a standard drop in speaker in next loco 165 for comparison.

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Demo sound of prolonged braking with lots of wagon flange squeal. Turn your volume up. :)

 

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