Multiple Paired Xmitters/Receiver Pairs

Thread Starter

djsfantasi

Joined Apr 11, 2010
6,196
I want to use Bluetooth to connect multiple sound sources to a common amplifier, with a small defined area. The transmitter pairs might be up tp 150 feet of each other and a nearby Bluetooth pair might be within 150 feet to it's neighbor. There might be 6-10 pairs of Bluetooth transmitters within a 4,000 to 8,000 square foot area.

Am I going to run into problems?
 
You would have to us Class 1 Bluetooth devices to get the range. The range is about 100 Meters line of sight, any intervening walls or other obstructions will attenuate the signal and lose range.
You can connect one master to up to seven slaves but your description indicates you are attempting to connect one slave to multiple masters. I am certain that will not work.
You also indicate a mesh network is desired. Basic Bluetooth doesn't support mesh networks but there is a mesh network capability available using Bluetooth LE: https://www.bluetooth.com/blog/introducing-bluetooth-mesh-networking/
You should consider other IOT devices that have mesh network capability and the ability to send data to a single master. The main problem you will have is how to multiplex or combine the audio. You will need high bandwidth to obtain and process all sources. If you only need one channel at a time you will need to mute all sources except the one of interest.

Yes, you are going to have problems but they are not insurmountable.
 

Thread Starter

djsfantasi

Joined Apr 11, 2010
6,196
You would have to us Class 1 Bluetooth devices to get the range. The range is about 100 Meters line of sight, any intervening walls or other obstructions will attenuate the signal and lose range.
You can connect one master to up to seven slaves but your description indicates you are attempting to connect one slave to multiple masters. I am certain that will not work.
You also indicate a mesh network is desired. Basic Bluetooth doesn't support mesh networks but there is a mesh network capability available using Bluetooth LE: https://www.bluetooth.com/blog/introducing-bluetooth-mesh-networking/
You should consider other IOT devices that have mesh network capability and the ability to send data to a single master. The main problem you will have is how to multiplex or combine the audio. You will need high bandwidth to obtain and process all sources. If you only need one channel at a time you will need to mute all sources except the one of interest.

Yes, you are going to have problems but they are not insurmountable.
@CharlesWMcDonald

To clarify, I am pairing one master to one slave, in line of sight (nothing intervening) at a distance of 45m or less.

I do not need a mesh network. One to one devices. Multiple independent pairs...

In an area approximately 20 m squared, there may be 6-10 such pairs. 6-10 pairs of one transmitter and one receiver.

Does this change your answer?
 

BobTPH

Joined Jun 5, 2013
2,266
So each receiver is paired with one transmitter, and all of the outputs are combined to go to one amplifier?

If that is correct, all you need is 6-10 separate transmitters, 6-10 separate receivers and one 10 input active audio mixer.

Bob
 

Thread Starter

djsfantasi

Joined Apr 11, 2010
6,196
Close, but there are 6-10 pairs of amplifiers, too. That is, 12-20 amplifiers.

The amplifier/speakers are a custom product, whose output can only be heard in a 5’ square space...
 
@CharlesWMcDonald

To clarify, I am pairing one master to one slave, in line of sight (nothing intervening) at a distance of 45m or less.

I do not need a mesh network. One to one devices. Multiple independent pairs...

In an area approximately 20 m squared, there may be 6-10 such pairs. 6-10 pairs of one transmitter and one receiver.

Does this change your answer?
Yes, it doesn't seem that it would cause any problems to have that many sets operating in the space you describe. I misunderstood your original post. Bluetooth uses spread sprectum with 79 channels so I think there would not be an issue operating with the number of devices you are using. If you increased the number of devices you will increase the potential of interference. It is difficult to determine the maximum number, certainly 79 pairs would have issues. Even half that number may have issues but 10 pairs would probably work.
 

Thread Starter

djsfantasi

Joined Apr 11, 2010
6,196
Yes, it doesn't seem that it would cause any problems to have that many sets operating in the space you describe. I misunderstood your original post. Bluetooth uses spread sprectum with 79 channels so I think there would not be an issue operating with the number of devices you are using. If you increased the number of devices you will increase the potential of interference. It is difficult to determine the maximum number, certainly 79 pairs would have issues. Even half that number may have issues but 10 pairs would probably work.
Thanks for your comments. I appreciate your advice.

One more thing... there are likely to be 6-10 WiFi networks in the same space. With between 3-5 nodes on each network. Is the addition of this requirement going to cause problems?
 
It is hard to figure out the topology with the information given, can you draw a map? Your requirements are evolving, give us complete details instead of dribbling them out over a number of posts.

Just given that you have a max of 50 nodes (10 networks with 5 nodes) and 79 available channels carrying audio then yes, you will have issues. Unless you have some way to limit the amount of audio or isolating the devices in some way. If you are distributing audio files instead of live audio and can pre-distribute the files then you may be able to get them pushed out.

This looks like a problem waiting for a different solution. You should consider something other than Bluetooth.
 

Thread Starter

djsfantasi

Joined Apr 11, 2010
6,196
@CharlesWMcDonald

I don’t feel like my requirements are evolving. The original question was about 10 Bluetooth transmitter pairs separated by 150 feet. It still is valid with no changes suggested by me.

Bluetooth is being used to transmit live audio from a mixer to a pair of speaker amplifiers in the ceiling wirelessly. No cables are allowed into the ceiling. The entire layout of audio components will be reconfigured every few weeks.

I asked if Bluetooth and WiFi can coexist in the same space. You answered the questions about Bluetooth. My last question is will WiFi interfere with Bluetooth?

In lieu of a map (one cannot be drawn), here’s a new description of the environment, presented in a hierarchical structure.

I will have 10 different zones...

Within each zone, I will have two services.

One service is a single Bluetooth Transmitter / Receiver pair

The second service is a WiFi network, containing five nodes, with sparse communications.
 

BobTPH

Joined Jun 5, 2013
2,266
Every post you make leaves me with less of an idea of what you are trying to do. First there is one speaker, then there are 20, now there are two with a mixer that was not there before.

I give up.

Bob
 

Thread Starter

djsfantasi

Joined Apr 11, 2010
6,196
Every post you make leaves me with less of an idea of what you are trying to do. First there is one speaker, then there are 20, now there are two with a mixer that was not there before.

I give up.

Bob
Thanks for your earlier comments. As far as I can tell, it hasn’t been done before. I have turned the model upside down from the way similar situations have been handled in the past.
  • This is because my requirements include reconfiguring in a short window of time.
  • Also, I am using an expensive proprietary system instead of amplified speakers.
  • Other solutions are built of one centralized sound source; I require multiple sound sources.
Plus various other differences.

The discrepancies you’ve noted are due to a simplification I chose to make, as describing the environment takes two pages of typed material.

For example, I want a Bluetooth pair in an environment of nine other such pairs.

A complete description of 20 DSS amplified speakers, 10 Bluetooth Receivers/Transmitters, 10 mixers, 50 mono to stereo splitters, 50 sound sources divided amongst the mixers, 50 stereo splitters, 50 microprocessor controlled MP3 players, SD cards, hierarchy of the preceding and the sound cable topology... seemed to be overkill for answering if Bluetooth pairs can coexist in a constrained space.
 
Thanks for your earlier comments. As far as I can tell, it hasn’t been done before. I have turned the model upside down from the way similar situations have been handled in the past.
  • This is because my requirements include reconfiguring in a short window of time.
  • Also, I am using an expensive proprietary system instead of amplified speakers.
  • Other solutions are built of one centralized sound source; I require multiple sound sources.
Plus various other differences.

The discrepancies you’ve noted are due to a simplification I chose to make, as describing the environment takes two pages of typed material.

For example, I want a Bluetooth pair in an environment of nine other such pairs.

A complete description of 20 DSS amplified speakers, 10 Bluetooth Receivers/Transmitters, 10 mixers, 50 mono to stereo splitters, 50 sound sources divided amongst the mixers, 50 stereo splitters, 50 microprocessor controlled MP3 players, SD cards, hierarchy of the preceding and the sound cable topology... seemed to be overkill for answering if Bluetooth pairs can coexist in a constrained space.
I think this certainly qualifies as feature creep! Lots of new information here, most of it meaningless without understanding the topology.
 

Thread Starter

djsfantasi

Joined Apr 11, 2010
6,196
As an added note. It will be impossible to understand the topology unless you are familiar with DSS audio systems. Are you familiar with the technology? Check out Holosonics. More information cane be found here and here. I had another thread and my biggest challenge was people not understanding the technology.

Without that understanding, the topology cannot be understood. As well as other features appearing inscrutable without understanding the objective.

I can’t share some of that information. Which is why I asked simply if I can have multiple paired Bluetooth transmitters / receivers within a confined area with multiple WiFi networks in the same space.
 
Every post you make leaves me with less of an idea of what you are trying to do. First there is one speaker, then there are 20, now there are two with a mixer that was not there before.

I give up.

Bob
I give up as well, almost every post contains new data. It seems the goal is to ask questions, not get answers.
 

Thread Starter

djsfantasi

Joined Apr 11, 2010
6,196
@CharlesWMcDonald and. @BobTPH ,

I was able to get a direct answer to my second question at ETO. after only two posts. If you feel like it, I’m curious why you found it difficult. It would help me in formulating my questions in the future.

I asked two questions.
  1. Can I run multiple Bluetooth pairs within a small space. Charles answered this in post #7.
  2. Will Wi-Fi networks interfere with Bluetooth. We never got this question answered definitely.
first, bluetooth range is limited to 35ft (10 meters). bluetooth signals are 1Mhz wide, so there's not a huge problem with them sharing spectrum space, but if there are wifi devices present , or nearby, they will cause problems with the bluetooth links. the 2.4Ghz band is a very crowded chunk of spectrum, and also includes microwave ovens. i worked for almost 10 years at a major retailer's service center. out of all the failures of bluetooth audio devices, by far the most common was interference. the system worked fine at the service center, and in the store when the customer picked it up, but when they got home it would fail again. sometimes, the customer could fix the problem by putting the bluetooth receiver closer to the transmitter, or by moving their wifi devices further from the bluetooth equipment. the largest number of interference problems were in apartment complexes, where everybody has wifi, bluetooth devices, microwave ovens, cordless phones, and baby monitors, all of which share the same bit of spectrum. you can do a site survey with a Software Defined Radio that can operate in the 2.4Ghz band (the cheap SDR dongles don't go above 2.0Ghz, so you need to find one that does go to about 2.5Ghz. with that most SDR software can show you the signals present in the 2.4Ghz band, and with some, you can save a plot of the activity in a 24 hour period. that can give you a clue whether all of the bluetooth devices will or will not be interfered with. the only remaining problem is increasing the range by a factor of about 4.5. there may be antenna options (like a "cantenna" to extend the range (highly directional), or passive boosters that increase the antenna "aperture".
After this discussion. I plan on having one Bluetooth transmitter/receiver pair in each zone (whatever how many it is). Networking will be hardwired gigabit Ethernet ( however many network nodes it happens to be. )

Thanks for your help.
 

TeeKay6

Joined Apr 20, 2019
572
@CharlesWMcDonald and. @BobTPH ,

I was able to get a direct answer to my second question at ETO. after only two posts. If you feel like it, I’m curious why you found it difficult. It would help me in formulating my questions in the future.

I asked two questions.
  1. Can I run multiple Bluetooth pairs within a small space. Charles answered this in post #7.
  2. Will Wi-Fi networks interfere with Bluetooth. We never got this question answered definitely.


After this discussion. I plan on having one Bluetooth transmitter/receiver pair in each zone (whatever how many it is). Networking will be hardwired gigabit Ethernet ( however many network nodes it happens to be. )

Thanks for your help.
@djsfantasi
Now you just have to learn how to handle the IoT's: doorbells, bedwarmers, pet feeders, security alarm systems, individual light bulb controls, alarm clocks, etc, etc. :D:D:D:D:D
 
2.45GHz is not the only ISM band and Bluetooth is not the only protocol available. If you look around you may find a band and protocol with sufficient bandwidth and channels to do what you want better than Bluetooth. I haven't looked but a little research may provide the answer.
 
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