Best Of New Adventures in Loco Hi-Fi

[Chris333]

I have no idea if this will work in this small a space, but when a woofer box is not able to have enough volume for the speaker you can use polyfill inside the box to make the speaker think the box is bigger.

[kiwi_bnsf]

I have no idea if this will work in this small a space, but when a woofer box is not able to have enough volume for the speaker you can use polyfill inside the box to make the speaker think the box is bigger.

Polyfill acts as a damper to the sound waves — minimising unwanted harmonics and ringing in small enclosures. It essentially does the same job as foam (which I'm now testing in the air space between the rear of the speaker and the shell).

Adding a damper inside my speaker enclosures is unfortunately not really possible as the internal volume is too small, and it will contact the driver of the cell phone speaker — which is very bad as it attenuates its movement.

Cheers!

[peteski]

Thanks for your continuing research Tim - very interesting findings.

[Olivani]

Impressive, loving it !

Oliver

[samusi01]

@kiwi_bnsf

A question, if I may - and apologies if I missed it - did you experiment with any different chamber wall thicknesses?

I am making my first foray into designing and printing chambers and the first versions have 0.5mm wall thickness. Would be interested in finding out what your thoughts are.

Sam

[kiwi_bnsf]

Good question.

I started out with designs that had 0.4mm wall thickness, and found this to be both too fragile and quite "buzzy" in terms of sound (I'm using standard Anycubic grey resin).

0.5mm thickness is nice and reliable, and I use 0.6-0.8mm where I need a more robust feature (like an unsupported wall).

I have also taken to adding 0.5mm fillets on all the inner joins as this makes things quite a bit stronger.

I have found that the dimensional accuracy of the Z axis with my Anycubic Mono X printer is not quite as reliable as the X and Y axis, so I have taken to printing my speakers in an upright orientation and I build in internal supports where necessary (as the automatic ones added by slicer software are not reliable enough for me with these tiny sizes).

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My designs are limited by the width of a locomotive's long hood (often 10.2mm or narrower), and so the wall thickness around the 9x16mm speaker itself is often pushed a bit lower (in some cases as low as 0.3mm), but this is only about creating a tight seal around the speaker… the remainder of the chamber uses 0.5mm wall thickness.

Hope that this info helps!

[samusi01]

Thank you very much! I do appreciate your post. I've got some experimenting to do, and a few Ole Wulff speakers en route.

[GaryHinshaw]

(It's annoying that they don't make a 9x23mm, as that would fit in quite a few of my larger locos)

I've been dipping my toes back into sound to see if I can tolerate it [] and I was looking back at this magnificent thread.  In my searches I came across a new speaker from CUI that is 9 x 25 mm:

https://www.digikey.ca/en/products/detail/cui-devices/CMS-250903-18SP-X8/18742616   (Canadian link, but other outlets also carry them)

These are a perfect size for many Kato locos.  I haven't made a sound box for them yet so I haven't had a chance to seriously evaluate their sound quality,  but I thought they would be worth sharing.  The THD curve is a bit off-putting, but we'll see.

I also purchased a 14 x 20 mm model to try out in a fuel tank....  But I'm not anxious to mill a bunch of frames if the payoff is marginal.

https://www.digikey.ca/en/products/detail/cui-devices/CMS-201437-24SP-X8/18742618

[kiwi_bnsf]

I've been dipping my toes back into sound to see if I can tolerate it [] and I was looking back at this magnificent thread.  In my searches I came across a new speaker from CUI that is 9 x 25 mm:

https://www.digikey.ca/en/products/detail/cui-devices/CMS-250903-18SP-X8/18742616   (Canadian link, but other outlets also carry them)

These are a perfect size for many Kato locos.  I haven't made a sound box for them yet so I haven't had a chance to seriously evaluate their sound quality,  but I thought they would be worth sharing.  The THD curve is a bit off-putting, but we'll see.

Thanks for the heads-up on these 9x25mm speakers @GaryHinshaw. That would fit my enclosures for the Kato SD70M, Kato SD9043MAC, and might just about fit the IMRC SD45-2.

I will order some to test

I had hoped to post some more detail on my progress with further speaker enclosure iterations this year, but work and life have got in the way, and all my spare moments have gone into sound projects.

However, I have managed to progress the following enclosures to the point of full prototype testing…

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These all sound pretty good, and have correct negative spaces for factory light pipes and LEDs.

The BLI AC6000CW ESU Loksound conversion turned into a labour of love/hate, but thankfully I only have one on my roster and it's pretty much done.

My next task is to prototype a small satellite PCB with integral SMD resistors to make it more convenient to solder headlights and ditch lights to the AUX functions on the Loksound V5 decoders (I've got quite a few installs to do, and hand building SMD resistor banks is getting very tedious).

Cheers

[ednadolski]

However, I have managed to progress the following enclosures to the point of full production testing…

Nice! a few quick questions:

 - Any ETA on when I could buy some of these?  (Beta level works fine for me)

 - The Kato SD70M also should fit the SD70MAC?

TIA,
Ed

[kiwi_bnsf]

Hi Ed,

- Any ETA on when I could buy some of these?  (Beta level works fine for me)

Good question.

I do have plans to eventually put BLW speakers up on a website for sale, but not anytime in the near future due to time constraint. I have a very busy life with work and family currently, and it maybe a few years before I can devote more time to this hobby.

I’ve thought about open sourcing all the STLs, but there are a few commercially-minded people who I fear might just take advantage, and I’ve already sunk at least a hundred hours time into my speaker library. Instead I'm planning to eventually run this more on a cover-my-production-costs basis, but shipping from my home in New Zealand to the continental US is quite pricey (USD15-25.00).

At the moment I'm just focusing on testing and refining my designs, and I'll share documentation of the various installs (including the milling requirements) as I complete them.

- The Kato SD70M also should fit the SD70MAC?

Yes, the SD70M internals and chassis are basically identical.

I will be sure to post a comparison of 9x16mm vs 9x25mm SD70M enclosures when my new speaker order arrives 

Cheers

[James Costello]

Great work Tim. I'm another interested party here, watching with interest and I'd eventually like to obtain some of these as well in what ever manner works for you - at least the shipping to Australia won't be too bad!

There seems to be a network of like minded individuals popping up every day sharing files and print capacities, becoming distributors for each other etc etc. I know some of the other designers use etsy as a platform too.

Anyway, great work and a nice solution to a problem.

[Jbub]

I'm interested as well, but the loco's I have aren't on the list. I've got Kato SD70 Ace's, ES44's and Scale trains ET44's. It's going to be a while until I get to them though, so I'll watch in anticipation.

[dangerboy81]

I've been dipping my toes back into sound to see if I can tolerate it [] and I was looking back at this magnificent thread.  In my searches I came across a new speaker from CUI that is 9 x 25 mm:

https://www.digikey.ca/en/products/detail/cui-devices/CMS-250903-18SP-X8/18742616   (Canadian link, but other outlets also carry them)

These are a perfect size for many Kato locos.  I haven't made a sound box for them yet so I haven't had a chance to seriously evaluate their sound quality,  but I thought they would be worth sharing.  The THD curve is a bit off-putting, but we'll see.

I also purchased a 14 x 20 mm model to try out in a fuel tank....  But I'm not anxious to mill a bunch of frames if the payoff is marginal.

https://www.digikey.ca/en/products/detail/cui-devices/CMS-201437-24SP-X8/18742618

I put one of those 9x25mm speakers in an SD70MAC to replace a 8x12 I had with what I think was a faulty air chamber It sounded better, but again, I think the smaller speaker had an air leak or one of the walls was too thin. Some of you guys have done way more work with sound in these models than I have, and I am learning a lot from you guys. I just want my models to sound better.
this link will jump you to the meat and potatoes, instead of sitting through my cringie preamble.

https://youtu.be/8oQxddewkiE?si=D4H-EH2ijj6BqsQc&t=734