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Smoggy

Audio Attenuators, Any Audiophiles Out There?

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One for the geeks and audiophiles, I get very lost on speaker impedances and db's.

I want to take the external speaker output on my vhf radio to a bluetooth transmitter for streaming to hearing aids but assume it will overload the transmitter fed direct, how do I work out what resistances to use to cut the signal?

I believe the output is 4.5w max and 4 ohm and assume the transmitter will need line level in, any ideas?

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Hi Smoggy 

In pub at the mo - quick thought, I think you need a line out - speaker too high level and low impedance - can you give a bit more info on your radio? 

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Radio is a standard horizon GX1500E, more than that I don't know, specs says audio power 4.5W 4 ohm and that's it, I may be able to get more info from standard horizon as their service bunch are very good.

I've seen a few examples online but mostly for much higher speaker levels than a vhf external jobbie.

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does it have a standard headphone socket, 

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Hi Smoggy 

Think speaker output is not best option with respect to others, get back to you tomorrow other wise 

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16 hours ago, grendel said:

does it have a standard headphone socket, 

No just the external speaker output.

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Doesn't that model have the option to switch the external speaker output to fixed level for use with an amplified speaker? If so, would you need an attenuator at all? Most modern bluetooth transmitters are very forgiving with the input level. 

I've said before, and happy to say again that Howard knows way more than me on these things but just a thought.

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I would agree with Pauls assessment if the output is, in effect, as Paul describes, a low level high impedance output. Perhaps we would need sight of the manual or someone local could take a look. I've also sent you a PM Smoggy, hope this is OK.

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All I can get from standard horizon is the 4.5w 4 ohm figure, the settings in the menu is just to turn off the internal speaker, the standard horizon ext speakers are not amplified just passive so I assume it's quite a high level output.

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Hmmmm. We that makes sense. So it's not a line out. 

I'm a member of a vintage radio forum, the members there are very helpful. I wonder if a forum exists for equipment of this nature??? 

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Thanks for the input and assistance chaps, this little beastie may well be what I'm looking for:

Line converter

Cheap enough to give it a go and see what goes bang.....

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Yes, that certainly looks interesting. That was one of my concerns, the impedance mis match. It also has a level control. 

I agree with Paul's comment re the Bluetooth - I don't think it will be too fussy and you are not looking at hifi so the sound quality shouldn't be an issue. 

My main concern is to present a load for the output. However I guess these devices are for short term intermittent use. For 3 quid I don't suppose you're anything to lose!  Caveat emptor though!!!! :default_biggrin: 

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5 hours ago, Smoggy said:

standard horizon ext speakers are not amplified

IIRC the MLS310 is amplified and that should be compatible with your radio, however something in the back of my head is telling me the facility to fix the output level is on the telephone style handset option, is that the VH310? Given that they share the 310 model number you might need to handset to use the speaker, and hence to fix the output level.

Sorry I'm not being much help, I'm teetering on the edge of understanding!

 

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3 hours ago, NorfolkNog said:

My main concern is to present a load for the output. However I guess these devices are for short term intermittent use.

The vast majority of the time there is no sound output at all so hopefully should prevent any damage to the radio, I did find a couple of radios with bluetooth function but they were stupidly expensive.

Next question is how do I manipulate the audio signal to make the scouser on the radio at gt.yarmouth understandable? Are babel fish available?

  • Haha 2

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