Legomanbiffo earth movers fitting questions

[Talltim]

Quite jealous of you with your full width 1/76 locos. Never going to fit an EM2 in a 1/87 hood loco!

[Chamby]

Has anyone cut down the EM2 to make it smaller? It strikes me with all the chassis grinding going on, taking even 5mm off the length could help retain more structure in the remaining chassis block.

 

I have cut the end off an EM2 and had a peep inside, the oval diaphragm is not driven, being a simple reflex diaphragm. With a little careful cutting and gluing, there is the potential to take a few mm off the length which would help with some installations. I’m not sure how much this would impact on the reflex performance though.

 

More drastically, the reflex end could be removed completely, halving the length. I would expect this to have an impact on performance but by how much?

 

Just wondering if anyone has actually tried this yet, before I consider having a go myself...

 

Phil

[Revolution Mike B]

All to do with frequencies! they work well in some projects but are crap on others.

 

Our Demo 8F has 2 X High Bass in the tender!    Charlie

Cheers Charlie, I'll swap it out for a pair of those then.

[Talltim]

Has anyone cut down the EM2 to make it smaller? It strikes me with all the chassis grinding going on, taking even 5mm off the length could help retain more structure in the remaining chassis block.

 

I have cut the end off an EM2 and had a peep inside, the oval diaphragm is not driven, being a simple reflex diaphragm. With a little careful cutting and gluing, there is the potential to take a few mm off the length which would help with some installations. I’m not sure how much this would impact on the reflex performance though.

 

More drastically, the reflex end could be removed completely, halving the length. I would expect this to have an impact on performance but by how much?

 

Just wondering if anyone has actually tried this yet, before I consider having a go myself...

 

Phil

I'd have thought that what make the speaker good, is the relationship beteen the active and passive drivers and the volume and shape of the enclosure. As soos as you start messing with those, it become just like any other speaker.

[The Nth Degree]

I agree with Talltim; the enclosure dimensions have been calculated and tuned precisely for the driver and passive radiator for best performance. Opening up a vent or altering dimensions will severely affect its dynamic range.

[Revolution Mike B]

Yep. If you remove any length from the end of the chamber, it needs to be added to the width or depth to keep the same volume. The reason these speakers sound so good is down to the passive radiator moving more air around.

[Chamby]

Oh well. Thanks guys. :-( Was worth asking.

[RBAGE]

Cheers Charlie, I'll swap it out for a pair of those then.

What is the benefit of fitting 2 identical speakers whose output has been halved by the method of fitting?

[Chamby]

What is the benefit of fitting 2 identical speakers whose output has been halved by the method of fitting?

You get twice as much noise out before they start distorting.

[RBAGE]

You get twice as much noise out before they start distorting.

Ah! Understand. But you'll get the same volume with no distortion because each speaker is half the output.

 

Is that right?

[Revolution Mike B]

Ah! Understand. But you'll get the same volume with no distortion because each speaker is half the output.

 

Is that right?

 

Not quite. The high bass speakers are 8 ohm so in parallel, the resistance will be 4 ohm and therefore more efficient    

[tractor_37260]

Stirling work that Ken !

Makes the '37 look easy !

Its clear that the chassis block no longer gives any rigidity but  a snug fitting EM in the recess may well change that .

Perhaps we shouldn't fear the 2 part chassis block 

 

"Perhaps we shouldn't fear the 2 part chassis block"

 

Nope  - chassis now fixed with a couple of pieces of thin steel sheet glued in place with Araldite METAL adhesive resin, good/strong as new, and the body still fits on easily due to the steel sheet pieces being no thicker than the plastic chassis frame.  Next job fix that 37 chassis I dropped and broke in two  !! 

[campbellad123]

I have long been a massive fan of the EM2's, and I'll fit them in any loco I think will benefit from it. The only niggle, the high end clarity doesn't exist.

 

This weekend I was shown and heard first hand how great the iPhone 6 speakers sound.

I wondered if I could use both an EM2, and iPhone 6 speaker.

 

The iPhone speaker is roughly 23.5ohm, and EM2 is 4ohm. Using an online calculator, It gave roughly 3.4 ohms when using both speakers in parallel.

 

If I reduce the volume slightly, will the V4 cope with the less resistance? I assume that the V4 has a cutout as to not damage the decoder.

 

Any help would be greatly appreciated.

 

Andrew

[Revolution Mike B]

I have long been a massive fan of the EM2's, and I'll fit them in any loco I think will benefit from it. The only niggle, the high end clarity doesn't exist.

 

This weekend I was shown and heard first hand how great the iPhone 6 speakers sound.

I wondered if I could use both an EM2, and iPhone 6 speaker.

 

The iPhone speaker is roughly 23.5ohm, and EM2 is 4ohm. Using an online calculator, It gave roughly 3.4 ohms when using both speakers in parallel.

 

If I reduce the volume slightly, will the V4 cope with the less resistance? I assume that the V4 has a cutout as to not damage the decoder.

 

Any help would be greatly appreciated.

 

Andrew

 

The only problem with this is that you'd hardly hear the iPhone speaker!

[campbellad123]

Shame, all I wanted was just a slight hint of higher frequencies to give an all round performing sound. I may try it, I just hope there is an automatic cut off for the amp if there's an overload etc

[Albie the plumber]

Hi Folks , 

A tad disappointed tonight ,

Having had my  '37 with EM 2 sitting in its milled chassis sounding great with the body off , it was time to reunite it with the body .

I had fitted lights to it as its the earlier model , no problem , the body fitted on without a problem ,

Put it on the rolling road and hit F1 on the controller .

When the '37 fired up ,I realised that I had been caught out .

As I've said previously , the body fitted like a dream , this had been checked several times throughout the project .

What I didn't bank on was the round speaker cone slapping on the underside of the bodyshell roof when sound was initiated .

 

The speaker cone reverberates wildly as I assume is normal .

To prove the theory that this was the problem , the fan was removed and a bright light was shone at one of the cab end windscreens .

This allows you to see daylight when looking through the windows of the other cab .

It also allows you to see the speaker cone slap against the bodyshell when you hit F1 .

 

It seems that I should have allowed space for movement of the speaker cone within its ' Kinematic envelope '  ( if that's the correct use of the term )

The bottom of the EM cant be filed down , not without risk of damaging  the little circuit board .

Grinding of the underside of the bodyshell is risky and unlikely to work .

So what seems to be the only viable option is to strip the model back to the chassis block and  get the file out again   

I just wondered if anyone else has been caught out like this 

 

I think I might put it away until the new year and concentrate on getting my layout up and running and return to it when I get my sound mojo back .

[Albie the plumber]

Having slept on it , could it be eliminated by turning the volume down ?????

[bigal10]

I don’t think so, Albie,

 

Charley and Bif are at great pains to tell users that the cones need quite a bit of space to move!

 

I had to Dremel quite a bit out of my Hornby 31 to make it work, but well worth the effort

 

Alan.

[tractor_37260]

Having slept on it , could it be eliminated by turning the volume down ?????

Albie

 

Unlikely. Without actually checking I think the volume on the WD file is set at 170 as supplied,  I had the same problem on my first 37 EM fitment, I originally ran the end to end wiring in a loop over the speaker, worked fine with the body off, with the body on the wiring fowled the cones, sound kept distorting/spitting.crackling etc, re-routing the wiring solved my issues. Is your speaker fitted in the middle or towards the end of the chassis ?  If it's under the fan grille, the fan mounting assembly should be removed, especially if the "round" speaker cone is under it.

Making the chassis recess slightly deeper may solve your problem, depending on how much clearance there is at present, between the base of the speaker and top edge of the motor ? 

 

Stick with it, you'll get there................

 

HTH

 

Ken

[Revolution Mike B]

The EM2 speaker needs a lot of space to work properly. Both the driver and passive radiator move considerably and you really need a decent void, otherwise you're wasting your time.

 

To put this is to perspective, take a Hi-Fi speaker and put a large piece of MDF right in front of it and see what it does to the sound image!

 

It's bad enough that they fire downwards in my Tractors but at least the sound waves can escape easily.

Edited November 29, 2017 by scoobyra

[Albie the plumber]

   Thanks to the last 3 Gentlemen who replied to the post !

 

Will now not waste time messing about with the volume .

 

Ken , the EM is centrally placed as I fancied keeping the fan and also both the bodyshell fixing points .

 

With Hindsight ( wonderful thing that ! ) I should have dispensed with the fan and placed it underneath

 

the Fan grille .

 

This would also allow more room for hard wiring the decoder .

 

Another day older , another day wiser

 

It wont take long to strip down ,its just the time wasted ....... Oh and I hate filing ! 

Edited November 29, 2017 by Albie the plumber

[Revolution Mike B]

I'm looking at putting an EM2 in my Hoover - there's loads of space beneath the fan grill and the speaker will sit over the top of the bogie without needing to remove too much material. Watch this space.

[Albie the plumber]

I'm looking at putting an EM2 in my Hoover - there's loads of space beneath the fan grill and the speaker will sit over the top of the bogie without needing to remove too much material. Watch this space.

 

Bought a V4 with Jamie Goodman's class 50 sounds over a year ago .

Still in the drawer awaiting fitment  along with 4 others !

 

So many sound chips , so little time !   

[D400]

I'm looking at putting an EM2 in my Hoover - there's loads of space beneath the fan grill and the speaker will sit over the top of the bogie without needing to remove too much material. Watch this space.

 

Having fitted an EM2 to a Class 50, your best option is the other end of the loco as where the fan grill is the chassis is narrower than the EM2. Compared to other installations Hornby Class is relativity straight forward, although still a fair amount of material to come out! 

 

Bruce

[tractor_37260]

The EM2 speaker needs a lot of space to work properly. Both the driver and passive radiator move considerably and you really need a decent void, otherwise you're wasting your time.

 

To put this is to perspective, take a Hi-Fi speaker and put a large piece of MDF right in front of it and see what it does to the sound image!

 

It's bad enough that they fire downwards in my Tractors but at least the sound waves can escape easily.

 

I've found, on a 37, I'd agree with Steve Brammer, an EM2 sounds even better when it's enclosed inside the body/chassis, maybe more work but worth the effort, it can be done...............