# JBL or ESU speaker - which would you use?



## tommyheadleycox (Oct 15, 2010)

I have room in my Märklin 1 gauge BR38's tender for a speaker up to 3 1/2 inches. I have 2 speakers on hand that fit: A 3 inch (78mm) 32 ohm ESU and a 3 1/2 inch JBL. There's obviously a difference in performance. But the 8 ohm is too loud. I'll have to install a pot on the Loksound Xl.

I also milled out a spot inside the boiler for a second speaker, facing forward. Then I temporarily removed the Witte smoke deflectors and drilled several 4mm holes to allow sound out. I replaced the deflectors and the holes are invisible. I can use a 30 x 40 mm speaker I took out of an old PC as the front tweeter; or I can use the tweeter from the same JBL control 23 speaker that I raided for the woofer. If I do that, I might as well install 2 potentiometers, one for each stage of the Loksound XL, so I can easily control the volume. I'd rather do that than play with the CV's. 

The little computer speaker and the 3 inch ESU speaker are well balanced and not too terribly loud, and I would't HAVE to install any pots. The JBL's speakers sound better but are too loud and need to be balanced in volume so 2 pots are mandatory. Should I forget the JBL's along with the pots and drink wine instead? Or should I "go the extra mile?"

Regards,
Tom


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## Garratt (Sep 15, 2012)

You really should try and match the impedance of the speaker to the amplifier's specifications. The speaker's impedance is a part of the circuit to function as designed. The lower volume of the ESU speaker is probably due to it having a higher resistance of 32 Ohms. You can wire several speakers in series or parallel to change the impedance load.

Andrew


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## Dan Pierce (Jan 2, 2008)

Some ESU decoders required 32 ohm speakers. Need to know decoder specs before suggesting speaker impedances.


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## Garratt (Sep 15, 2012)

Dan, yes exactly. If the ESU spec needs a 32 Ohm load, putting lower impedance speaker/s on could 'cook' the amp.

Andrew


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## tommyheadleycox (Oct 15, 2010)

From pg. 19 of the Loksound XL user manual:
================
The LokSound XL V4.0 has two speaker outputs working with about 10V each. 
• If you wish to use both speaker outputs each speaker should have an impedance of 8 Ohms or higher. 
==============
I’m definitely going to use both outputs so it seems clear to me that any 2 speakers above 8 ohms will be safe. (No 4 ohm speakers allowed.) What’s going on now is that while I like the amazing bass of the 3.5 inch 8 ohm JBL woofer, it’s too loud. On the other hand, the ESU 3.0 in. 32 ohm speaker has less bass, but its volume is just right. If I want to keep the JBL, it’s mandatory that I install a 100k ohm potentiometer, as per page 20 of ESU’s XL decoder instructions, so that I can turn the volume down. This installation is a slight pain to do, involving 3 - 6 very small soldering pads on the decoder, and the problem of affixing and hiding the pot. But well within my capabilities. I was just wondering what other folks may have down when faced with this choice.

Regards,
Tommy


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## Garratt (Sep 15, 2012)

I'm not sure exactly but you may be able to put a resistor, perhaps 8 ohms (maybe lower), in series with the speaker. The load will be higher but within the operating specs. The speaker should then be half the volume??. You will need a resistor that can handle the wattage.

Andrew


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## Semper Vaporo (Jan 2, 2008)

You may find that the speakers are loud on your workbench in the house, but once outside on the track you may want even more volume from them!


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## tommyheadleycox (Oct 15, 2010)

Garratt said:


> I'm not sure exactly but you may be able to put a resistor, perhaps 8 ohms (maybe lower), in series with the speaker. The load will be higher but within the operating specs. The speaker should then be half the volume??. You will need a resistor that can handle the wattage.
> 
> Andrew


Excellent idea. Thanks for reminding me that I could do this rather than hassle with installing a pot.
Since I have resistors lying around, it can't hurt to try and I definitely will. BTW, one of the reasons I'm doing all this is that there's a truly amazing effect of realism to the steam sounds if you can get a tweeter mounted way up front in the boiler and a woofer mounted way in back in the tender, such that the high frequencies appear to be coming from where they should - the engine. Meanwhile the low frequencies from the tender can't be differentiated in location. So the chuff has a huge booming sound. And the wide physical separation of the 2 speakers lends almost a stereo effect. I guess I'm insane or compulsive but it's been fun to seek the most realism I can.

Regards,
Tom


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## tommyheadleycox (Oct 15, 2010)

Semper Vaporo said:


> You may find that the speakers are loud on your workbench in the house, but once outside on the track you may want even more volume from them!


You're right and I will test that right away. I was so zeroed in on close up sound I forgot the big picture. Thanks!
Tom


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## Cataptrra (Mar 16, 2015)

If it were me, I'd still install the pots for volume control! Even though outside sounds are great, after a while even mine get to after awhile and I want to lower them. 

I use old Phoenix '97 Sound systems in my loco's and they came with a pre-wired volume control{toggle switch, momentary SPDT type} and many times I just want to either turn the sound down or off because it's late at night and I don't want to disturb the neighbors. Or I just want to lower the sound because after a few hours of running, I just want a softer level of sound, because the loud sound can get very annoying after awhile {at least to me it does!}.

So I'd definitely add the volume controls, if you don't, you might wish you did later, so do it now and you won't have to go back and try and make changes later to put them in.

And if they stick out underneath the tender along one side or the other, as long as the shafts aren't too long, they wouldn't really be all that noticeable. Not unless your train is elevated to eye level where one could easily see under the tender, but if on the ground or at a distance crossing a trestle or bridge, you'll hardly notice them.


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## tommyheadleycox (Oct 15, 2010)

Hi, Orville,

Thanks for the reply. I was thinking like you, and decided I wanted the pots even if I didn't need them. The one remaining Radio Shack store in my area had some 100K audio trimmers/potentiometers, very small. So they're not obtrusive. One odd thing is that there seems to be only a High or Low volume response from the pots. It's not continuously variable.

Regards,
Tom Cox



Cataptrra said:


> If it were me, I'd still install the pots for volume control! Even though outside sounds are great, after a while even mine get to after awhile and I want to lower them.
> 
> I use old Phoenix '97 Sound systems in my loco's and they came with a pre-wired volume control{toggle switch, momentary SPDT type} and many times I just want to either turn the sound down or off because it's late at night and I don't want to disturb the neighbors. Or I just want to lower the sound because after a few hours of running, I just want a softer level of sound, because the loud sound can get very annoying after awhile {at least to me it does!}.
> 
> ...


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## toddalin (Jan 4, 2008)

tommyheadleycox said:


> Hi, Orville,
> 
> Thanks for the reply. I was thinking like you, and decided I wanted the pots even if I didn't need them. The one remaining Radio Shack store in my area had some 100K audio trimmers/potentiometers, very small. So they're not obtrusive. One odd thing is that there seems to be only a High or Low volume response from the pots. It's not continuously variable.
> 
> ...


That's because you are using an incorrect pot. What you want is an L-pad with a resistance comparable with the amp.

If the speaker runs at 16 ohms and your pot is 100K ohms, as soon as you start to turn the pot, you have _way more_ resistance than necessary and waste "the "movement" on the pot.

Also, I would bet that the audio pot is rated nowhere near the actual power output of the amp.


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## Garratt (Sep 15, 2012)

Tom. If you can't get a pot that fits easy, another option is a small switch wired to a resistor so you can have 2 volume settings. Loud and Soft in case it is too overwhelming. I also find sound can become annoying when it is not the best quality.

Andrew


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## Dan Pierce (Jan 2, 2008)

Use a SPDT center off with 2 resistors. Now there are 3 volume settings.


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