Speaker selection : LGB 2074D Spreewald 2-6-0

[notofthiscenturyTim]

I am digitising an LGB 2074D Spreewald. I would appreciate advice on speaker size, model and placement especially from anyone who's done this previously.

I think possible locations are: round speaker behind firebox, sugar cube style inside the side tanks or inside the rear of the cab.

I am fitting a pulsed smoke generator so that rules out the front of the boiler. The other parts in the build are:
- DCC decoder mXion Drive-M in middle of boiler
- SUSI sound module mXion SX6 in boiler
- pulse sensor (Taktgeber in German)

Thanks!

 

[LGB333]

I am digitising an LGB 2074D Spreewald. I would appreciate advice on speaker size, model and placement especially from anyone who's done this previously.

I think possible locations are: round speaker behind firebox, sugar cube style inside the side tanks or inside the rear of the cab.

I am fitting a pulsed smoke generator so that rules out the front of the boiler. The other parts in the build are:
- DCC decoder mXion Drive-M in middle of boiler
- SUSI sound module mXion SX6 in boiler
- pulse sensor (Taktgeber in German)

Thanks!

Hello Century! I can tell you how I've done DCC sound conversions on smaller LGB steam locomotives such as your model. I remove the factory board install a DCC sound decoder such as an ESU 5XL being my favority for sound quality and features. I also install and sell Massoth and Soundtraxx Tsunami2 decoders. On the smaller steamers I use a 40mm 3 Watt 8 Ohm round speaker fitted and sealed inside the firebox with holes drilled into the front.......see photo below. Sound quality is excellent.

Using a two decoder approach like you're planning isn't ideal for several reasons including fitment inside a boiler; using a single DCC sound decoder is also much easier to install and maintain. And with the ESU 5XL sound decoder, you don't need to use a clock generator to produce the pulses for the sound decoder or pulsed smoker. The ESU decoder produces the pulses for the smoker based upon the decoder's chuff sounds so the wheels, chuff and smoker can all be in sync. The only downside is you must use an ESU LokProgrammer to set up the ESU 5XL for the smoker's operation. I use the Massoth Round Boiler Pulsed Generators and a few of its decoder CVs also need changes to work optionally with the ESU decoder. You can go onto my Website and see various demo videos of customers' LGB locomotives I've converted to DCC sound using the ESU 5XL sound decoders to hear the high quality of the sounds.

Note that I use epoxy putty sometimes to mount and seal smaller speakers where screws can't be used. You'll also note in the photo below I used the putty to mount a volume control board.

 

[idlemarvel]

There's a document on the Massoth wiki which lists the speaker size required for nearly every LGB loco and many PIKO ones. When I'm back home I'll try and add a link to it.

 

[notofthiscenturyTim]

Hello Century! I can tell you how I've done DCC sound conversions on smaller LGB steam locomotives such as your model.

Thank you very much for this detailed and comprehensive reply. The 40mm speaker looks like a good option. Thanks also for the putty tip and the link to the videos. I think I'm going to open the locomotive too and see if I can measure it before ordering the speaker to be on the safe side.

I was planning on installing the external clock generator to get the smoke and sound better synchronised with the cylinder pistons, but maybe it's overkill and I should just go for the internal clock generation - there's a CV in this decoder too which can be switched between internal/external generator. The external pulse generator is connected to the loco decoder, which then sends the pulse to the sound module via SUSI, and it also directly controls the pulsed smoker.

In terms of decoder choice I'd also prefer a single board solution. The SUSI sound module I'm planning on using is pretty small, 20x27mm and I've previously fitted it and a decoder inside a Stainz, which is also a tight squeeze. To be honest the choice mostly comes down to price for me - the mXion decoder plus SUSI sound module plus smoke generator are £105 compared to around £295 for an ESU 5XL and Massoth smoker.

 

[LGB333]

There's a document on the Massoth wiki which lists the speaker size required for nearly every LGB loco and many PIKO ones. When I'm back home I'll try and add a link to it.

Dave, I've attached the Massoth Speaker Guide. It's primarily helpful for LGB locomotives for replacing a factory-installed speaker that will fit in the speaker holder in the locomotive. But for LGB locomotives that were never produced with a sound system, such as the Spreewald, it's just a suggestion. For example, for the Spreewald, the Guide shows the below speaker, but the 40mm round speaker I suggest is a much better option.......the large size speaker and wattage.

821x074 8241050 28mm / 1W (Visaton) LGB 2x742 (Spreewald)

 

[notofthiscenturyTim]

There's a document on the Massoth wiki which lists the speaker size required for nearly every LGB loco and many PIKO ones. When I'm back home I'll try and add a link to it.

Many thanks. I've tracked it down and it suggests a 28mm, 1W made by Visaton. I think that will definitely fit, but I'm going to see if anything bigger might work too.

The 28mm Visaton units' datasheets show they have barely any bass frequency response (under 250hz) and poor response in the mid-range up to 500hz. That doesn't sound great to reproduce the sounds of a steam engine to me. Whereas there are 32mm and 37mm options from Visaton which are good down to 200hz and OK to 100hz.

 

[notofthiscenturyTim]

Dave, I've attached the Massoth Speaker Guide.

Many thanks. Didn't see you post while I was replying to Dave. I agree it's worth trying to fit something bigger. Now out with the screwdrivers to investigate the internal space more closely!

 

[Greg Elmassian]

Remember for bass output, you really need a sealed chamber behind (or in front of) the speaker, and it needs a bit of volume (not sound, but 3d space)

Often better to use a slightly smaller speaker in a sealed enclosure vs one in free air....

Greg

 

[LGB333]

Many thanks. Didn't see you post while I was replying to Dave. I agree it's worth trying to fit something bigger. Now out with the screwdrivers to investigate the internal space more closely!

Here's the 40mm carbon fiber 3 watt 4-8 Ohm speakers I use. Made in China, of course, but work super for small spaces. And like Greg states, it's critical to seal the speaker's metal frame to the mount so there are no air gaps. I first use a small paint brush to apply Extra Thick Maxi-Cure Cyanoacrylate glue onto the outter raised ridge and press it into place, then apply the epoxy putty all arund the base of the speaker to hold it into place. I have several demo videos on my Website of smaller LGB locomotives with this speaker installed and they sound super. You can get this 40mm speaker on eBay.

 

[Greg Elmassian]

Yep, you can tell a lot about a speaker from just looking at it. The butyl surround (what connects the frame to the moving cone) gives longer excursion, needed for bass notes.
carbon fiber adds stiffness but keeps the cone light... stiffness helps low frequencies, light weight helps high frequencies.

a dome in the middle will help dispersion of high frequencies (not normally needed for our applications), but does give a bit more surface area for radiation of sound.

the size of the magnet though, is almost immaterial what is most important for efficiency and sound reproduction is hidden inside where you cannot see it, in the gap with the voice coil.

Greg

 

[notofthiscenturyTim]

Here's the 40mm carbon fiber 3 watt 4-8 Ohm speakers I use. Made in China, of course, but work super for small spaces. And like Greg states, it's critical to seal the speaker's metal frame to the mount so there are no air gaps. I first use a small paint brush to apply Extra Thick Maxi-Cure Cyanoacrylate glue onto the outter raised ridge and press it into place, then apply the epoxy putty all arund the base of the speaker to hold it into place. I have several demo videos on my Website of smaller LGB locomotives with this speaker installed and they sound super. You can get this 40mm speaker on eBay.

View attachment 313568

Thank you, the extra details about the speaker and fitting are super helpful. I think I've narrowed it down to a 32-40mm one, depending on the space available and allowing for a proper enclosure.

 

[notofthiscenturyTim]

Yep, you can tell a lot about a speaker from just looking at it. The butyl surround (what connects the frame to the moving cone) gives longer excursion, needed for bass notes.
carbon fiber adds stiffness but keeps the cone light... stiffness helps low frequencies, light weight helps high frequencies.

a dome in the middle will help dispersion of high frequencies (not normally needed for our applications), but does give a bit more surface area for radiation of sound.

the size of the magnet though, is almost immaterial what is most important for efficiency and sound reproduction is hidden inside where you cannot see it, in the gap with the voice coil.

Greg

Thanks, this is really useful in understanding how speaker design can affect performance. I feel way better informed in making a decision!

 

[Greg Elmassian]

Another specification is sensitivity, normally 90 = db at 1 meter.... the more sensitivity, the more efficient, but in my experience most modern units have plenty of volume.

More efficient speakers usually have poorer frequency response (physics tells you that you never get something for nothing)

Greg

 

[notofthiscenturyTim]

Another specification is sensitivity, normally 90 = db at 1 meter.... the more sensitivity, the more efficient, but in my experience most modern units have plenty of volume.

More efficient speakers usually have poorer frequency response (physics tells you that you never get something for nothing)

Greg

Thanks, hadn't considered that. One more question, do you happen to know the thickness of the 40mm speaker? The eBay listings I've looked at don't specify it.

 

[Greg Elmassian]

That is a question for Tom

 

[notofthiscenturyTim]

Here's the 40mm carbon fiber 3 watt 4-8 Ohm speakers I use. Made in China, of course, but work super for small spaces. And like Greg states, it's critical to seal the speaker's metal frame to the mount so there are no air gaps. I first use a small paint brush to apply Extra Thick Maxi-Cure Cyanoacrylate glue onto the outter raised ridge and press it into place, then apply the epoxy putty all arund the base of the speaker to hold it into place. I have several demo videos on my Website of smaller LGB locomotives with this speaker installed and they sound super. You can get this 40mm speaker on eBay.

View attachment 313568

Thanks for this suggestion do you happen to know the thickness of the 40mm speaker? The eBay listings I've looked at don't specify it.

 

[Greg Elmassian]

if he does not pop up, you can message him...

 

[LGB333]

Thanks for this suggestion do you happen to know the thickness of the 40mm speaker? The eBay listings I've looked at don't specify it.

Sure, it's 20mm.

 

[notofthiscenturyTim]

Sure, it's 20mm.

Thanks. That sounds ideal.

 

[notofthiscenturyTim]

Sure, it's 20mm.

A brief update. I installed the speaker you linked in the roof of my Stainz earlier today. Previously it had a 28mm speaker in a "sugar cube" type housing. The difference is incredible. Way more volume and bass. And less rasping and tinny. Thank you so much for the recommendation.
I'm still waiting on the decoder and sound module for the Spreewald. I ordered two of the speakers as the price for two was barely more than for one and I reckoned the Stainz could be improved too.