Sound box for speaker

[barnaclebill]

I just installed a LokSound Nano in a Bachmann 2-8-0 Consolidation. The speaker is a 9x16mm "sugar cube" from sbs4dcc.com. I can't tell if the sound box is supposed to go on the front or back! I would think it should go on the back, to make the speaker more like a tiny version of my home stereo speakers, but the leads are on the back so it won't fit flush unless I modify it a bit or use gooey glue. It fits flush against the front of the speaker but that seems counterintuitive. Any suggestions?

[Jbub]

I just installed a LokSound Nano in a Bachmann 2-8-0 Consolidation. The speaker is a 9x16mm "sugar cube" from sbs4dcc.com. I can't tell if the sound box is supposed to go on the front or back! I would think it should go on the back, to make the speaker more like a tiny version of my home stereo speakers, but the leads are on the back so it won't fit flush unless I modify it a bit or use gooey glue. It fits flush against the front of the speaker but that seems counterintuitive. Any suggestions?

The point of the enclosure is to isolate one side of the speaker membrane from the other. One of the biggest contributors to sound quality is the volume of the enclosure (capacity, not sound) with bigger being better. When you mount the speaker with the leads inside the enclosure, you reduce the volume of the enclosure, because of the wire and speaker back being inside it. It's also easier to install the leads on the outside anyway, just make sure you protect them. If you you short the two together, you'll release the magic smoke in the sound chip and it will be as quiet as a much cheaper non-sound decoder.

[jdcolombo]

The SBS4DCC enclosures are designed for the speaker "front" to face into the enclosure, with the wire leads on the outside.  It IS counterintuitive, but it works fine, and in fact there are a couple of people who have compared speaker performance who found that these "inward"-facing setups actually sound better than "outward"-facing.

Glue the front of the speaker to the enclosure with thick CA, attach wires to the leads on the outside, and you're golden.

John C.

[tehachapifan]

Completely agree with the above responses. I've done several custom N scale installs, have tried both ways and can't tell any difference. It is nice having the speaker diaphragm facing inward to protect it from damage and so that the leads are easily accessible on the outside without having to route the wires into the enclosure (as was mentioned above).

[barnaclebill]

Thanks everyone. That worked for me and it sounds great! Now I just need to figure out why I hear sounds when Mute is on and no sound when Mute is off.

[peteski]

We could help if you expand on this a bit.  What model? What decoder? How do you mute it? That would be a good start.

EDIT: Duh!  I missed the LokSound in the initial post. John has the explanation covered.

[jdcolombo]

LokSound sound decoders "mute" the sound depending on whether F8 is on or off.  "Normal" behavior is to turn the sound on when F8 is on, and turn the sound off when F8 is off.  But this behavior can be reversed, so that the sound comes on when F8 is off, and is muted when F8 is on.   Some people prefer this reversed behavior, so that sound comes on automatically when they power up their layout.  Some manufacturers also do it this way for OEM LokSound decoders, so that they don't get calls from purchasers who refuse to read instructions asking "where is the SOUND????" when they haven't pressed F8 to turn the sound on.  Atlas, for example, used to do this (don't know if they still do).

If you are using F8 to "mute" the sound, then this particular Nano may have the behavior of F8 reversed.  If you have a LokProgrammer, it is relatively simple to change the F8 behavior back to "normal".  If you do not have a LokProgrammer, and do not have access to one via a friend or sympathetic dealer, you can change the behavior of F8 via CV programming, although I do not recommend this route because it is so easy to screw it up (although you should be able to get back to where you were by doing a factory reset).  If you do not have a LokProgrammer and want to know how to change the behavior of F8 via CV programming, let us know.  I can post that information.

John C.

[kiwi_bnsf]

Glad you got a good result!

Count me as one of the people who prefers cell phone speakers with the membrane facing inwards into the speaker enclosure (and the contacts therefore conveniently located on the outside).

I did some pretty exhaustive semi-scientific tests with custom 3D printed enclosures, and the ones with the wires inside didn't sound as good (even with the wire holes being very carefully sealed).

There are some YouTube videos of my tests in this thread: https://www.therailwire.net/forum/index.php?topic=55532.msg763194#msg763194

Cheers

[peteski]

Count me as one of the people who prefers cell phone speakers with the membrane facing inwards into the speaker enclosure (and the contacts therefore conveniently located on the outside).

I did some pretty exhaustive semi-scientific tests with custom 3D printed enclosures, and the ones with the wires inside didn't sound as good (even with the wire holes being very carefully sealed).

That is strange as those speakers in their intended application (used as transducers in smart phones, tablets or similar devices) have the membrane facing out of the enclosure (baffle).  Same goes for home stereo speaker systems (it would be surprising to have nice HiFi speaker system with the speakers mounted with the basket and magnet facing out.

But we do whatever works for us. Good sounding audio design can be quite complicated.

[kiwi_bnsf]

That is strange as those speakers in their intended application (used as transducers in smart phones, tablets or similar devices) have the membrane facing out of the enclosure (baffle).  Same goes for home stereo speaker systems (it would be surprising to have nice HiFi speaker system with the speakers mounted with the basket and magnet facing out.

For the tiny cubic capacities available in cell phones and smaller laptops, the inward facing orientation is a common design. In tear down photos you often just see the metal rear casing of the speaker integrated with a labyrinthine speaker box. This is also why the CUI and OLW speakers often come in versions that include an adhesive surround on the membrane-side of the speaker so that it can be a press-fit into an enclosure.

Here's a typical design for a smaller Samsung cell phone:




Here's a MacBook Pro 15" with an inward facing speaker and circular passive radiators:



Speaking of passive radiators, I find it very interesting to see ESU adopting the same combination of an inward facing speaker, and a passive radiator to get more bass:

https://www.esu.eu/en/products/accessories/loudspeakers/speaker-22mm-x-42mm/

It's unfortunate that I can't really replicate this in my BLW N scale enclosures — they are just too small.


We are definitely not done when it comes to achieving better sound in tiny enclosures — I have high hopes for MEMS solid state speakers in a few years…

https://www.techradar.com/news/the-future-of-audio-worlds-first-solid-state-speakers-may-transform-earbuds

I'm very grateful that the mass market for ear buds and cell phones has some technology spillover into this hobby 

[peteski]

Interesting.  Thanks Tim!

[GGNInNScale]

For those of us that are a bit older  ,  we might recall the Ohm speakers of the 1970's where the backside of the cones were open to the room...

[Mike C]

For those of us that are a bit older  ,  we might recall the Ohm speakers of the 1970's where the backside of the cones were open to the room...

 The Walsh speakers ?  Those are odd !

[GGNInNScale]

Yep, the Walsh drivers.  The sound basically "launched" from the cone based partially on the resonance and mechanical impedance along the cone, on top of the overall cone motion.  There were a couple sizes of the Ohms.  The tweeter was an inverted version of the woofer with an embossed metal cone and foam supports.