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This may sound like a dumb question but are the wires which connect a sound decoder to its speakers just the same as those you would use to connect power supply to decoder or decoder to motor?
I am going to add an extra speaker to a sound decoder and this question just dawned on me. I'm assuming they are the same but are they?

cheers

Neil
 

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QUOTE (neil_s_wood @ 6 Dec 2007, 13:26) <{POST_SNAPBACK}>This may sound like a dumb question but are the wires which connect a sound decoder to its speakers just the same as those you would use to connect power supply to decoder or decoder to motor?
I am going to add an extra speaker to a sound decoder and this question just dawned on me. I'm assuming they are the same but are they?

cheers

Neil

***Neil, the wire is the same:

However, when you say you are adding another speaker be sure that they are of similar efficiency, that the impedance is correct and that by adding another speaker you do not lower the combined overall impedance of the speaker(s) to below the design limits of the sound decoder or you will destroy the amplifier section - and thats not a warrsnty covered thing!

Richard
 

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QUOTE (Richard Johnson @ 6 Dec 2007, 17:36) <{POST_SNAPBACK}>***Neil, the wire is the same:

However, when you say you are adding another speaker be sure that they are of similar efficiency, that the impedance is correct and that by adding another speaker you do not lower the combined overall impedance of the speaker(s) to below the design limits of the sound decoder or you will destroy the amplifier section - and thats not a warranty covered thing!

Richard

Thanks Richard

How would you know if combining them would lower the overall impedance? They are both ESU decoders and speakers so I was assuming compatibility in most respects.
 

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A speaker is an electric motor driven by current from the audio amplifier that is its' power supply. The audio amplifier on a sound decoder will be designed to deliver the current required by a specified impedance speaker. Connect a second speaker of the same type in parallel, and the impedance halves. That means that the current draw on the amplifier doubles. That's more heating in the decoder. Whether the decoder is adequately specced to stand up to this needs to be determined before doing the experiment.
 

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QUOTE (neil_s_wood @ 6 Dec 2007, 16:14) <{POST_SNAPBACK}>Thanks Richard

How would you know if combining them would lower the overall impedance? They are both ESU decoders and speakers so I was assuming compatibility in most respects.

***Neil, if you parallel them you'll get 50 ohms, which is the lowest acceptable on the ESU, however I'd recommend turning the volume down to about 90% if you do it - this slightly conservative setting will make a great difference to the heat generation and it'll still be louder than a single speaker.

are they both 23mm??

Richard
 

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QUOTE (Richard Johnson @ 6 Dec 2007, 23:41) <{POST_SNAPBACK}>***Neil, if you parallel them you'll get 50 ohms, which is the lowest acceptable on the ESU, however I'd recommend turning the volume down to about 90% if you do it - this slightly conservative setting will make a great difference to the heat generation and it'll still be louder than a single speaker.

are they both 23mm??

Richard
Thanks Richard and 34c,

one is the standard 23mm speaker the other is a 40 by 20 mm speaker. I was advised to get the biggest sized speaker that would fit. I figured that I could get both of these into the tender of a 9f.
 

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QUOTE (neil_s_wood @ 7 Dec 2007, 06:32) <{POST_SNAPBACK}>Thanks Richard and 34c,

one is the standard 23mm speaker the other is a 40 by 20 mm speaker. I was advised to get the biggest sized speaker that would fit. I figured that I could get both of these into the tender of a 9f.

***Hi Neil, that'll work fine, and you'll be pleased with the result. The polarity isn't marked on ESU speakers but if you stay consistent (ie same wire to left terminal of both speakers etc) they'll be in phase and work well.

Richard
 

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Discussion Starter · #8 ·
QUOTE (Richard Johnson @ 7 Dec 2007, 13:05) <{POST_SNAPBACK}>***Hi Neil, that'll work fine, and you'll be pleased with the result. The polarity isn't marked on ESU speakers but if you stay consistent (ie same wire to left terminal of both speakers etc) they'll be in phase and work well.

Richard
Excellent, thanks very much for your advice Richard.
 

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QUOTE (neil_s_wood @ 7 Dec 2007, 03:06) <{POST_SNAPBACK}>Excellent, thanks very much for your advice Richard.


I would look at the base reflex speakers for steam tenders. Very good, though too big for most diesels!
 

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QUOTE I would look at the base reflex speakers for steam tenders.
Is that the DCC Supplies unit?

David
 

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QUOTE (Makemineadouble @ 11 Dec 2007, 23:25) <{POST_SNAPBACK}>I've used a lot of these 20 x 40 8 ohm flat speakers from ESU and their excellent, good service as well from DCC supplies.


I am using the 100 ohm version, I think they are different sizes to the std 20x40, perhaps slightly smaller?
 

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QUOTE (Makemineadouble @ 12 Dec 2007, 17:51) <{POST_SNAPBACK}>I got sent a batch of 100 ohm speakers by mistake and they were quite lot bigger, too big for a 4mm tender


***Ummmm this isn't making any sense at all.

The impedance has nothing to do with the size. 20x40 is 20x40 irrespective of impedance. All loksound speakers are 100 ohm (except the twin 16mm which is 2x 50 ohm)

- You cannot use an 8 ohm speaker of any size with a loksound - it will cook the audio outputs very fast. The 20x40 100 ohm will certainly fit most 4mm scale tenders as long as there's not a motor in there too.....

is there confusion in the size difference between the DCC supplies speaker with the ported chamber and the sealed chamber loksound perhaps??? The ported chamber version is slightly bigger.

Richard
DCCconcepts-
 

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The bass reflex speaker which Piemanlarger and I were referring too is larger than a 20x40mm speaker but looks an awful lot like it, probably because a 20x40 mm speaker is a component. The speaker photo in the Royal Scot review is of a bass reflex speaker. The "hole" for the reflex bit is visible at the left hand side.

David
 

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Hmm, now even I'm confused
Probably time to clarify......
Richard is correct (as always!) size has nothing to do with impedance. All our speakers are [as of Warley] available in Loksound compatible (100 ohm) or in 8 ohm for other decoders. All are manufactured to our specifications by a specialist speaker company. and built from the ground up, (with frame, diaphragm, voice coil and enclosure all being 'tweaked' for bass) there is no connection with ESU/Loksound

Due to the expanding range, we're in the process of changing some part numbers the XXX part is the speaker impedance, and the labels are also colour coded, Red for 8 ohm, and green for 100 ohm - very important these don't get connected to the wrong decoder!:

We have 3 types of Bass speaker, these are 'all in one' speakers which include an engineered, airtight enclosure and attached wires

1) Bass reflex (DCC01-XXX) This is 22mm wide by 58mm long and 9.3mm thick. Though they are 18mm longer than Loksound enclosures, they are half the height, which makes a huge difference in the ease of fitting, and will 'drop-in' to larger locos, smaller locos may need some modifications.

2) Bass reflex (DCC03-xxx) This is the new 'American' style, 18mm wide x 53mm long x 15mm high. Made for the narrow US style locos, but also great for steam locos.

3) Bass enhanced (DCC02-xxx) This is 20mm wide x 40mm long x 8mm thick. Not a 'reflex' design, but using top quality components we've managed to produce a ready to run speaker, that sounds better than anything else (other than our reflexes of course!) Due to the slim design, these will fit practically anywhere.

We have also made the 'bare' speakers available, as the rubberised cloth diaphragm, frame and voice coil we use will significantly improve over 'traditional' mylar speakers. These units must be built into an airtight chamber for best results (as with any speaker) and are available in 8 and 100 ohm types in 20mm x 40mm and 16mm x 35mm sizes.

I hope this helps clear the fog a little. Full information can be found on our website here: http://tinyurl.com/2or29d (Link via Tiny URL)

Best regards
Andy
 
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