Wireless line level connection

[jwilhelm]

Can anyone point me to a decent quality line level wireless transmitter/ receiver design? I've tried a couple ready made products that weren't overly impressive. I'd like to try to build something, but haven't had much luck searching.

 

[andyr]

I'd like to try to build something, but haven't had much luck searching.

I'm into DIY if:
a) the bought equivalent is too pricey for me, or
b) nothing ready-made, fits the bill.

But if you can buy something that works really well - and is not expensive - then why bother to spend your time building something?

I've tried a couple ready made products that weren't overly impressive.

Can you tell mw what these were?

I recently bought a pair of Miccus RTX units (so one set to 'transmit' mode ... the other to 'receive' mode). They work fantastically well Bluetoothing the output of a DVD player up one story of my house to where my preamp sits, so I can select that source and then drive (hard-wired) speakers which are next to the TV.


Regards,

Andy

 

[AlexQS]

I've been an Apple fan since the first generation iPod.

I recently got AppleTV. I can send music over wifi from iPhone, iPad, computer, or just stream it from iTunes.

From AppleTV it does optical output into a DAC.

I think it's far from the 3kazillion / 640million-bit (exadguration) stuff I see in the digital forum. I'm not really sure if it will really do the 96k/24b that my DAC can support, but it's at least 44.1/16 I think, and sounds great.

The thung I like about it is that it WORKS. No little hiccups, and since AppleTV2 is supposed to be out soon, if you can find the old one, it's only about $60 USD.

So that's my 2cents.

 

[DF96]

Building something to do this will almost certainly be illegal in most administrations. Licensed radio amateurs are allowed to build transmitters, but we are not allowed to transmit music. Everybody else has to buy commercial type-approved transmitters.

Having said that, for short range low power look at the FM transmitters intended for MP3 players etc. However, building a decent FM receiver is not easy; I know, because I have done it.

The reason you won't find DIY circuits for this is that RF DIY is difficult and often illegal.

 

[jwilhelm]

The room this is meant for is a large office area 60 x 40 meters, so bluetooth is out. My first thought when looking at the room was to use two Sonos connects grouped together, but the people operating this aren't skilled enough to work a remote control properly, so using an app on their phone would really confuse them.

I can't remember the name first couple units I tried (No name junk). I've got SainSonic units right now. All seemed to be lacking high frequency detail, and some basic testing with my junk scope/ test equipment showed signal dying off above 8khz.

900mhZ radio modules are available ready made and don't require special licencing if the power is kept withing reason. TXM-869-ES Linx Technologies Inc. | RF/IF and RFID | DigiKey I would assume I would need to convert audio to digital, transmit digitally, then convert back to analog to avoid interference, so I wouldn't be transmitting music.

I think I have an idea of what is required to make everything work, but it's always nice to see other ideas before diving in.

 

[AndrewT]

............... I would assume I would need to convert audio to digital, transmit digitally, then convert back to analog to avoid interference, so I wouldn't be transmitting music............

Furry logic (or funny).
Try convincing the mechanical copyright society.
To reproduce music in a commercial environnment is not covered by the "domestic" use licence you "buy" with a CD.
Look at the screen of a public house TV, they buy a licence to entertain the customers and it shows in the logo of a beer glass in the corner.

 

[jwilhelm]

I recently bought a pair of Miccus RTX units (so one set to 'transmit' mode ... the other to 'receive' mode). They work fantastically well Bluetoothing the output of a DVD player up one story of my house to where my preamp sits, so I can select that source and then drive (hard-wired) speakers which are next to the TV.

These units actually look promising, if they are actually able to work reliably at the advertised range in a noisy environment. Other normal Bluetooth devices get about 2/3 advertised range in the room. I've never experimented with extended range Bluetooth. I think I'll try these before building anything. Thanks.

 

[DF96]

You will be transmitting music. You may be violating the conditions under which those RF modules can be used licence-free - they are intended for data signalling.

For (almost) legal transmission of music within a building you need to use the technology intended for wireless microphones etc. This may be expensive, but the quality should be good. In Europe Sennheiser seem to be the market leader; maybe Shure in North America? Sennheiser bodypack transmitters have a line input, although they are more commonly used with microphones.

 

[jwilhelm]

You will be transmitting music. You may be violating the conditions under which those RF modules can be used licence-free - they are intended for data signalling.

For (almost) legal transmission of music within a building you need to use the technology intended for wireless microphones etc. This may be expensive, but the quality should be good. In Europe Sennheiser seem to be the market leader; maybe Shure in North America? Sennheiser bodypack transmitters have a line input, although they are more commonly used with microphones.

The actual signal would be data. I guess the poor bastards at Sony really need to make a buck at everything I do though.

I've looked into the wireless microphone idea. The music shop I deal with didn't make it sound very promising. I could talk to some others though.

 

[AndrewT]

The actual signal would be data............

more furry logic.
The data is copyrighted.
You need a licence to use that copyrighted material.

 

[jwilhelm]

more furry logic.
The data is copyrighted.
You need a licence to use that copyrighted material.

They're listening to radio stations. The idea is to be able to run them all from one source, because the people operating this thing are too lazy to walk to the other side of the room and have all audio sources match. I think Sony will survive without the royalties. If not, I won't miss them when they're gone.

 

[AndrewT]

And you don't even want to recognise the rights of the musicians !

It's the same logic used by the fakers of electronic components and shoes and perfumes.
It's criminal behaviour.

 

[jwilhelm]

And you don't even want to recognise the rights of the musicians !

It's the same logic used by the fakers of electronic components and shoes and perfumes.
It's criminal behaviour.

Seriously? You need to find a good porn site! I don't shell out money to listen to a radio station. The artist are supposed to be paid from the advertising done on the radio station. I'm sure Sony might actually pass on a minuscule portion to them. Weather the advertising is heard directly through a piece of wire or beamed to the other side of the room then listened to isn't going to change the fact that they are still making their royalties.

 

[DF96]

The actual signal would be data.

No. The signal would be music which has been digitally encoded. That type of signal would not normally be permitted in a frequency band intended for telemetry, industrial plant alarm signalling etc. However, provided you don't draw attention to yourself you will probably get away with it.

The matter of music copyright etc. is a different issue which I don't intend to comment on.