Installs Bluetooth input for gymnasium sound system

Butch!

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So one of our schools called today and said they were having problems connecting to the sound system in the gym via Bluetooth. Apparently someone bought this little gadget that can sync to a phone and puts out a line level signal that they plugged into the stereo input on the sound board.

The sound board is mounted to the rack which is in the closet next to the gym. So there is a cement block wall and bleachers full of people between their little gadget and the gym. Their complaint (big surprise) is that it works great when the phone is in the closet, but they can't seem to get it to work when the phone is in the gym.

This request came from the Superintendent for the District so "Bluetooth has a weak signal, that's how it is" isn't going to work. I'd mount their device in the gym up on the ceiling, but then they can't get to it to push the 'pair' button.

Does anyone know of some device that maybe uses remote antennas or is otherwise designed for this situation?

Thanks!!
 

MNicolai

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I usually give gyms a playback rack on a cart that plugs into an XLR plate somewhere that feeds back to the amp rack

Easiest thing is probably to blow a hole in the wall for a conduit sleeve, and stick an XLR plate on the wall where they can plug the Bluetooth widget into. If need be, you can get plastic flip covers like they have for FA pull stations and thermostats to protect the Bluetooth widget from taking a direct hit from the Volleyball team 7 times in a row.

Bluetooth is worthless after about 40' so if you put it on the ceiling you really need to be standing in the sweet spot for it to work.
 

MNicolai

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By the way, I would add that Bluetooth is generally inappropriate for this because it doesn't flush devices out of memory when you disconnect. Convenient though it may be, you don't want to caught off guard when you leave and come back a couple days later and your phone pairs back up with the PA system without alerting you. Now that private call or Snapchat you just got is broadcast over the PA system while you're on a 10-second delay realizing that your phone is still paired with the sound system. By the time you fumble through the menus to turn off Bluetooth that voicemail your doctor left about your test coming back positive has already been announced to the room.

Use at your own risk of peril. A wired input into the system is more forgiving.

That particular Denon unit won't play your audio from an active call, but that's not to say that it won't play your voicemails, Snapchats, Instagrams, and other sources of audio through the PA.
 
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rwhealey

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By the way, I would add that Bluetooth is generally inappropriate for this because it doesn't flush devices out of memory when you disconnect. Convenient though it may be, you don't want to caught off guard when you leave and come back a couple days later and your phone pairs back up with the PA system without alerting you. Now that private call or Snapchat you just got is broadcast over the PA system while you're on a 10-second delay realizing that your phone is still paired with the sound system. By the time you fumble through the menus to turn off Bluetooth that voicemail your doctor left about your test coming back positive has already been announced to the room.

Use at your own risk of peril. A wired input into the system is more forgiving.

That particular Denon unit won't play your audio from an active call, but that's not to say that it won't play your voicemails, Snapchats, Instagrams, and other sources of audio through the PA.
I agree with all, and that Bluetooth isn't ready for pro audio, but unfortunately Apple made the decision for us without asking...

Most of my clients in 2018 specifically requested bluetooth capability in everything from classrooms to large auditoriums. I would like to see a "pro" bluetooth device that is controllable by Crestron/AMX in such a way that a user can see what device is asking to pair on the touchscreen and OK it before having to manually unmute the audio (i.e, always starts muted). It also needs to you kick off a paired device so you can pair a new one.
 

Butch!

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Thank you everyone for your thoughts. I couldn't agree more that this Bluetooth idea is bad, especially as this is an unmanned system with no one to hit kill the phone if something inappropriate happens. Apparently they have someone sing the National Anthem at basketball games and she has her accompaniment on her phone so they want this for that. I set them up with an input so that she could plug into the phone's headset jack but they didn't like it because she couldn't stand center court and sing.

I'm looking into the Denon that @rwhealey mentioned. They don't give any info on the antenna, not even a picture so I don't know how 'remote' it is. I've put in a request to their tech dept, we'll see what happens.
 

urban79

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I just installed one of the Denons and have another on order... the antenna connects via BNC and has a magnet on the back like a Sirius radio antenna. It also has the option to add a remote pairing button. Our gym rack is in the corner of the gym but in the same room... so far has not given any difficulties reaching to the scoreboard table across the way, even with a gym full of people... as always ymmv

Chris
 

FMEng

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If you remote the antenna very far, use larger coaxial cable, such as RG-8 or LMR400. Bluetooth is 2.4 GHz, so small coax can be very lossy.
 

jayvee

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Thank you everyone for your thoughts. I couldn't agree more that this Bluetooth idea is bad, especially as this is an unmanned system with no one to hit kill the phone if something inappropriate happens. Apparently they have someone sing the National Anthem at basketball games and she has her accompaniment on her phone so they want this for that. I set them up with an input so that she could plug into the phone's headset jack but they didn't like it because she couldn't stand center court and sing.

I'm looking into the Denon that @rwhealey mentioned. They don't give any info on the antenna, not even a picture so I don't know how 'remote' it is. I've put in a request to their tech dept, we'll see what happens.
I have a couple of wireless mics in my gym setup and I give the person with the phone a beltpack with a TA4F to 1/4 with 1/4 to headphone jack adapter- then they can walk around wherever they want and still have control.
 

Butch!

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@urban79 Thanks for the additional info on the Denon. I'm still waiting on hearing back from them on the possibility of doing a remote antenna. @jayvee I had the same thought on giving them a belt pack, but the school only has a handheld wireless. I doubt they'll spring for another wireless system for this, but then again the Superintendent is asking for this . . .
 

jayvee

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@urban79 Thanks for the additional info on the Denon. I'm still waiting on hearing back from them on the possibility of doing a remote antenna. @jayvee I had the same thought on giving them a belt pack, but the school only has a handheld wireless. I doubt they'll spring for another wireless system for this, but then again the Superintendent is asking for this . . .
Worth a shot to sweet talk that Super! Also, if they are just trying to play music they can use a belt pack that goes with the mic receiver they already have - though that means either talk or music, not simultaneous, which could be a no-go.
 

stagemanager1

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I try to use a wired mic instead of wireless when I can get away with it. Bluetooth as accompaniment is a very ill conceived idea. An XLR cable with a direct box and a source with an output is the best way to go.
I have installed Denon CD players with bluetooth in a couple of dance classrooms and they work well, and the instructors love them. I personally have the Logitech bluetooth receiver in my kitchen sound system, and it works well, but the advice that you do not know when someone else's phone will connect is pertinent, especially if you do not have a finger on the volume knob.
 
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Chris15

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https://www.atterotech.com/products/bluetooth/analog-extension/unbt2a
Designed for the purpose, I assume priced accordingly, bluetooth radio with pairing button on a wall plate and a Catx connection back to the audio breakout. RS232 control, including the ability to disable said pair button.
Atterotech's AES67 and Dante products generally work well, so I have no reason to assume their other products have not been designed with a similar level of engineering...
 

Butch!

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@Chris15 That's a good find and a nice product to know about! But at $400 plus the cost of running the Catx cable back to the rack it would be less costly to go with a beltpack wireless transmitter and plug the phone into it.

I think I've managed to talk them out of Bluetooth due to the reliability issues and possible 'accidents' that could happen. It looks like it will be a hard line to the scoring table (via an existing mic jack) or a beltpack.
 

Chase P.

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"Accidents", right... When I was a youngster, I would have intentionally caused problems with that system. Everything in a school setting should be as bulletproof and air gapped as possible. Those seven volleyball strikes mentioned earlier? It's because the new A/V device on the wall looks like a target to the kids. I'd skip the plastic thermostat cover and go straight for a steel enclosure with padlock hasps, not a flimsy cam lock.
 
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teqniqal

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Bluetooth is worthless after about 40' .
This Denon model . . . I wouldn't believe the 100' range on the spec sheet...
The Bluetooth product group has three common power levels, the lowest one that is good for about 20 feet is the most common, but the highest power version is good to about 120'. The key is that BOTH THE TRANSMITTER AND RECEIVER must be the high power version so the they can talk to each-other at a distance.
 
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TimMc

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Bluetooth is like religion, politics, and social causes - best avoided in polite company... but since I'm not feeling polite I'll say this:

As the professional being consulted I would feel it my duty to address the problems of latency, security, fidelity, and cost for the 'best practices' equipment and installation. In addition, I would question why it was necessary for the performer to operate the playback device - is there a reason the music input at the scorer's table can't be used? Surely her mom, dad, or sibling can be trusted to press "play" for her. Apple even has a way to get analog audio out of an iFruit, a $10 adapter.

While the schadenfreude would be delicious, I don't see having a bluetooth failure at a home game very appealing to the Super... "in the interests of everyone looking "good", we recommend a cable and someone to push the play button."
 
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Butch!

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I was at the school today and met the Athletic Director and finally got the whole story on the Bluetooth request. The girl's basketball coach wanted to play music from his phone during warm up before the games so he strung together a bunch of adapters from Amazon until he got something that fit in the mic jack on the rack. It sound like crud so he then cut up one of his cables and tied directly into the rack mount mixer (terminal block inputs). It still sounded like crud (line level going into a mic level mixer) so they decided they must need new speakers. When I was up there over a month ago I properly hooked up to the mixer and played some music so they could hear that the speakers were not dead. So then they wanted a proper Bluetooth connection which is why I started this thread. After explaining all the issues which were raised here they have now said they don't want Bluetooth and to get them a direct box that they can plug the phone into.

So this bad idea is thankfully dead. Of course now they'll lose the direct box or the cable . . .

Thank you to everyone chipped in.
 

MNicolai

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So this bad idea is thankfully dead. Of course now they'll lose the direct box or the cable . . .

Thank you to everyone chipped in.
Whirlwind makes some nice MIP wall plates. They have a balancing transformer and ground lift and everything built in, and sum a stereo source down to mono and go line level into a mixer or DSP. May or may not work for you depending on where you want to give them access to this connection, but this is one way to make sure they don't lose the DI box, they can use any ready-made RCA/3.5mm cable to plug into it.

 

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