This is the essential part of a longer post (soon to be released at
major theatres).

This relates directly to cell phones.

So to turn off the built-in PC speakers I disabled them but no sound
comes from the Bose bluetooth hearphones even though they are still
listed as paired with the PC, although the phone also says that the
hearphones are paired with it!!!

Can they be listed as paired, either on the phone or the PC, but not
really be connected? Or can speakers or earphones be paired with two
sound-producers at the same time, like the pc and the phone? Will both
sounds come out at the same time, overlaying each other? (The phone
isn't making any sound now anyhow, and I don't want to fiddle because
the medical clinic is supposed to call right back.)

And now I just got bu-dup bu-dap-dup in my ears and I don't know who
sent it or what it means. Nothing on the PC screen or the phone gives a
clue. I thought maybe the hearphones were turning off but they haven't.

the built in speakers are still there and they are now listed as the
default, and now that I got a phone call, removed the hearphones (which
turn themslves off if neither ear has one.)

On 2/14/2022 4:40 AM, micky wrote:
> This is the essential part of a longer post (soon to be released at
> major theatres).
>
> This relates directly to cell phones.
>
> So to turn off the built-in PC speakers I disabled them but no sound
> comes from the Bose bluetooth hearphones even though they are still
> listed as paired with the PC, although the phone also says that the
> hearphones are paired with it!!!
>
> Can they be listed as paired, either on the phone or the PC, but not
> really be connected? Or can speakers or earphones be paired with two
> sound-producers at the same time, like the pc and the phone? Will both
> sounds come out at the same time, overlaying each other? (The phone
> isn't making any sound now anyhow, and I don't want to fiddle because
> the medical clinic is supposed to call right back.)
>
>
> And now I just got bu-dup bu-dap-dup in my ears and I don't know who
> sent it or what it means. Nothing on the PC screen or the phone gives a
> clue. I thought maybe the hearphones were turning off but they haven't.
>
> the built in speakers are still there and they are now listed as the
> default, and now that I got a phone call, removed the hearphones (which
> turn themslves off if neither ear has one.)

One headset cannot listen to two PCs at the same time,
because each PC has its own spread spectrum frequency hopping
pattern. It would take two radio chains, to do a good job in
your proposed design. The easiest way to do it, would be
for the headset to have two BT chips (one radio chain per chip)
and mix the audio together from the output of the chips.

Of course, no one would build that, because the battery life would
be affected.

I tried to run two BT audio devices off the PC, and I wasn't allowed to
do that. Even though Windows allows the Mixer to be bypassed, and you
can output two music streams to two speaker systems at the same time.
Winamp was always touted as the beast for this, but I've never got
any further at evaluating that idea.

I haven't tried running two dongles on the PC at the same time.

*******

And this is a hell of a lot more info, than you'd get from BT
Marketing Material.

https://en.wikipedia.org/wiki/Channel_access_method

"As an example, the Bluetooth communication system is based on a
combination of frequency-hopping and either

CSMA/CA statistical time-division multiplexing communication
(for data communication applications) or [CA=Collision Avoidance]

TDMA (for audio transmission). [Time Division Multiple Access]

All nodes belonging to the same user (to the same piconet) use the
same frequency hopping sequence synchronously, meaning that they
send on the same frequency channel, but CDMA/CA or TDMA is used
to avoid collisions within the VPAN. Frequency-hopping is used by
Bluetooth to reduce the cross-talk and collision probability between
nodes in different VPANs.
"

https://en.wikipedia.org/wiki/Time-division_multiple_access

"In dynamic time-division multiple access (dynamic TDMA), a scheduling
algorithm dynamically reserves a variable number of time slots in each
frame to variable bit-rate data streams, based on the traffic demand
of each data stream. Dynamic TDMA is used in ... Bluetooth"

Knowing a bit of the back story, makes it easier to predict what
functions it could have. In this case, it didn't help much.

*******

BT is allowed to do more than just "run your audio stream for you".
If it wants to beep or burp, it can. When it wants to pair, it
can make a pairing noise. My little BT speaker has a couple of
tonal patterns it uses, as well as a flashing LED.

Paul

In article <sudfjr$q2f$1@dont-email.me>, Paul <nospam@needed.invalid>
wrote:

> > So to turn off the built-in PC speakers I disabled them but no sound
> > comes from the Bose bluetooth hearphones even though they are still
> > listed as paired with the PC, although the phone also says that the
> > hearphones are paired with it!!!
> >
> > Can they be listed as paired, either on the phone or the PC, but not
> > really be connected? Or can speakers or earphones be paired with two
> > sound-producers at the same time, like the pc and the phone? Will both
> > sounds come out at the same time, overlaying each other? (The phone
> > isn't making any sound now anyhow, and I don't want to fiddle because
> > the medical clinic is supposed to call right back.)
> >
> >
> > And now I just got bu-dup bu-dap-dup in my ears and I don't know who
> > sent it or what it means. Nothing on the PC screen or the phone gives a
> > clue. I thought maybe the hearphones were turning off but they haven't.
> >
> > the built in speakers are still there and they are now listed as the
> > default, and now that I got a phone call, removed the hearphones (which
> > turn themslves off if neither ear has one.)
>
> One headset cannot listen to two PCs at the same time,

yes it can, known as bluetooth multipoint.

more common is multipair, where a headset is paired with multiple
sources but can only connect to one at any given time. switching is
usually manual, without the need to re-pair. some can auto-switch to
whichever source has active audio, including airpods and galaxy buds.

> because each PC has its own spread spectrum frequency hopping
> pattern. It would take two radio chains, to do a good job in
> your proposed design. The easiest way to do it, would be
> for the headset to have two BT chips (one radio chain per chip)
> and mix the audio together from the output of the chips.

complete rubbish.

> Of course, no one would build that, because the battery life would
> be affected.

yes they would, and have, and without any adverse effect on battery
life.

On 2/14/22 06:49, this is what Paul wrote:
> On 2/14/2022 4:40 AM, micky wrote:
>> This is the essential part of a longer post (soon to be released at
>> major theatres).
>>
>> This relates directly to cell phones.
>>
>> So to turn off the built-in PC speakers I disabled them but no sound
>> comes from the Bose bluetooth hearphones even though they are still
>> listed as paired with the PC, although the phone also says that the
>> hearphones are paired with it!!!
>>
>> Can they be listed as paired, either on the phone or the PC, but not
>> really be connected?  Or can speakers or earphones be paired with two
>> sound-producers at the same time, like the pc and the phone?   Will both
>> sounds come out at the same time, overlaying each other?      (The phone
>> isn't making any sound now anyhow, and I don't want to fiddle because
>> the medical clinic is supposed to call right back.)
>>
>>
>> And now I just got bu-dup bu-dap-dup in my ears and I don't know who
>> sent it or what it means.  Nothing on the PC screen or the phone gives a
>> clue. I thought maybe the hearphones were turning off but they haven't.
>>
>>   the built in speakers are still there and they are now listed as the
>> default, and now that I got a phone call, removed the hearphones (which
>> turn themslves off if neither ear has one.)
>
> One headset cannot listen to two PCs at the same time,
> because each PC has its own spread spectrum frequency hopping
> pattern. It would take two radio chains, to do a good job in
> your proposed design. The easiest way to do it, would be
> for the headset to have two BT chips (one radio chain per chip)
> and mix the audio together from the output of the chips.
>
> Of course, no one would build that, because the battery life would
> be affected.
>
> I tried to run two BT audio devices off the PC, and I wasn't allowed to
> do that. Even though Windows allows the Mixer to be bypassed, and you
> can output two music streams to two speaker systems at the same time.
> Winamp was always touted as the beast for this, but I've never got
> any further at evaluating that idea.
>
> I haven't tried running two dongles on the PC at the same time.
>
> *******
>
> And this is a hell of a lot more info, than you'd get from BT
> Marketing Material.
>
> https://en.wikipedia.org/wiki/Channel_access_method
>
>    "As an example, the Bluetooth communication system is based on a
>    combination of frequency-hopping and either
>
>        CSMA/CA statistical time-division multiplexing communication
>        (for data communication applications) or                      [CA=Collision Avoidance]
>
>        TDMA (for audio transmission).  [Time Division Multiple Access]
>
>     All nodes belonging to the same user (to the same piconet) use the
>     same frequency hopping sequence synchronously, meaning that they
>     send on the same frequency channel, but CDMA/CA or TDMA is used
>     to avoid collisions within the VPAN. Frequency-hopping is used by
>     Bluetooth to reduce the cross-talk and collision probability between
>     nodes in different VPANs.
>    "
>
> https://en.wikipedia.org/wiki/Time-division_multiple_access
>
>    "In dynamic time-division multiple access (dynamic TDMA), a scheduling
>     algorithm dynamically reserves a variable number of time slots in each
>     frame to variable bit-rate data streams, based on the traffic demand
>     of each data stream. Dynamic TDMA is used in ... Bluetooth"
>
> Knowing a bit of the back story, makes it easier to predict what
> functions it could have. In this case, it didn't help much.
>
> *******
>
> BT is allowed to do more than just "run your audio stream for you".
> If it wants to beep or burp, it can. When it wants to pair, it
> can make a pairing noise. My little BT speaker has a couple of
> tonal patterns it uses, as well as a flashing LED.
>
>    Paul
@Paul: I know it's an added expense, but could you use two headsets, pair one to the phone and one to the PC and then just use the left of
one set and the right of the other set? Yes, you lose stereo, but you do get 2 for 1. Kinda off base and out of the ballpark huh?!!

On 2/14/2022 1:40 AM, micky wrote:
> This is the essential part of a longer post (soon to be released at
> major theatres).
>
> This relates directly to cell phones.
>
> So to turn off the built-in PC speakers I disabled them but no sound
> comes from the Bose bluetooth hearphones even though they are still
> listed as paired with the PC, although the phone also says that the
> hearphones are paired with it!!!

Paired but not connected.

It's possible to do what you want to do, but you need Bluetooth
headphones with "multipoint" capability, you can't do it with standard
Bluetooth headphones.

See <https://phiaton.com/collections/earphones/products/bt-100-nc>.

micky,

> ... even though they are still listed as paired with the PC,
> although the phone also says that the hearphones are paired
> with it!!!

It depends a bit on the pairing process (it might not use a new, random
token for each pairing), but what you now possibly have are two devices
which both try to talk to your headphone while that headphone can only talk
to one device at a time. The result ? The poor thing can't talk to either
....

> Can they be listed as paired, either on the phone or the PC, but
> not really be connected?

Yes. Its rather normal that your headphones will only talk to the last
device you paired it with (thats what that "random token" is for I mentioned
earlier), and that one of those "I'm paired with the headsphone" that you
see on your phone and PC is not actually working - a remembrance of what
once was.

Please do check if the headphones currently communicate with either the just
the PC or the phone. If-and-when it does you have a normal, basic
headphone which can only be paired to a single other device (delete the old,
non-functioning pairing on the other device)

Although I've never heard of headphones which will connect to several
devices at the same time, I have seen devices which could be paired to
several devices at the same time, and have buttons to swich between using
those connections.

And such multi-pairing devices might even have a setting to look for a
present paired-with device and auto-select it.

Best to take a peek in the headphones users manual about what it can do and
how it behaves though. :-)

Regards,
Rudy Wieser

On 2/14/2022 7:51 AM, R.Wieser wrote:

<snip>
> Although I've never heard of headphones which will connect to several
> devices at the same time,

They exist, but are not common, see
<https://phiaton.com/blogs/audio/bluetooth-multipoint-pairing-what-is-it-and-how-does-it-work>

<https://phiaton.com/collections/headphones/products/bt-460>
<https://phiaton.com/collections/headphones/products/bt-390>
<https://phiaton.com/collections/multipoint-bluetooth/products/900-legacy>
<https://phiaton.com/collections/multipoint-bluetooth/products/bt-100-nc>

This would be a pretty nice feature these days with so many people
remote working. No need to switch headsets between listening to music or
other content, and doing online meetings on the computer.

In article <sudvas$fo8$1@dont-email.me>, sms
<scharf.steven@geemail.com> wrote:

> This would be a pretty nice feature these days with so many people
> remote working. No need to switch headsets between listening to music or
> other content, and doing online meetings on the computer.

airpods, released in 2016, auto-switch based on active audio and
proximity.

On 2/14/2022 9:43 AM, sms wrote:
> On 2/14/2022 1:40 AM, micky wrote:
>> This is the essential part of a longer post (soon to be released at
>> major theatres).
>>
>> This relates directly to cell phones.
>>
>> So to turn off the built-in PC speakers I disabled them but no sound
>> comes from the Bose bluetooth hearphones even though they are still
>> listed as paired with the PC, although the phone also says that the
>> hearphones are paired with it!!!
>
> Paired but not connected.
>
> It's possible to do what you want to do, but you need Bluetooth headphones with "multipoint" capability, you can't do it with standard Bluetooth headphones.
>
> See <https://phiaton.com/collections/earphones/products/bt-100-nc>.

And the secret sauce is Bluetooth LE 4.1 .

https://microchipdeveloper.com/wireless:ble-phy-layer

Channel Arrangement

The 40 channels are divided into three advertising channels (Ch. 37, 38, and 39),
and 37 data channels (Ch. 0-36).

Advertising Channel Usage

Device discovery
Connection establishment
Broadcast transmissions

Data Channel Usage

Bidirectional communication between connected devices
Adaptive frequency hopping used for subsequent connection events

*******

The original Bluetooth is described this way.

"Bluetooth uses a radio technology called frequency-hopping spread spectrum.
Bluetooth divides transmitted data into packets, and transmits each packet
on one of 79 designated Bluetooth channels. Each channel has a bandwidth of 1 MHz.
It usually performs 1600 hops per second, with adaptive frequency-hopping
(AFH) enabled.[23]

Bluetooth Low Energy uses 2 MHz spacing, which accommodates 40 channels"

"Bluetooth is a packet-based protocol with a master/slave architecture.

Further down

"One master may communicate with up to seven slaves in a piconet. All devices
within a given piconet use the clock provided by the master as the base
for packet exchange. The master clock ticks with a period of 312.5 μs,
two clock ticks then make up a slot of 625 µs, and two slots make up
a slot pair of 1250 µs. In the simple case of single-slot packets, the
master transmits in even slots and receives in odd slots. The slave, conversely,
receives in even slots and transmits in odd slots. Packets may be 1, 3, or 5
slots long, but in all cases, the master's transmission begins in even slots
and the slave's in odd slots.

The above excludes Bluetooth Low Energy, introduced in the 4.0 specification,
[25] which uses the same spectrum but somewhat differently.
"

It could be the three advertising channels, that help make
it possible for one slave to talk to two masters. But so far,
I don't see a description of how the advertising channels are
acquired for usage. The other 37 channels are used in a hopping
mode controlled by a master.

*******

https://devzone.nordicsemi.com/f/nordic-q-a/6411/can-two-masters-connect-two-slaves-at-the-same-time

"Yes, you are correct, S110 7 (BLE peripheral/slave softdevice) can be in a
connection and advertise in a non-connectable state simultaneously. But a
BLE peripheral can not be in a connection with two centrals/masters simultaneously.

However, with S110 8, a nRF51 peripheral/slave can be in a connection and
advertise in scannable mode and receive RSSI signals from any centrals/masters
in vicinity, therefore knowing of their presence. With that strategy, the peripheral
could disconnect from master 1 and establish connection with master 2, or
periodically alter connection between central 1 and central 2 and virtually
have 2 connections to 2 centrals."

[A "central" is just the politically correct synonym for "master" device]

Paul

In article <sue1jn$q8a$1@dont-email.me>, Paul <nospam@needed.invalid>
wrote:

>
> And the secret sauce is Bluetooth LE 4.1 .

multipoint support began with bluetooth 4.0, aka bluetooth le.

sms,

>> Although I've never heard of headphones which will connect to several
>> devices at the same time,

I stand corrected ... a bit. :-)

A quote from that first link you posted :

"This doesn't mean that you'll be able to stream audio from both connected
devices simultaneously"

What it /does/ decribe is that it can keep listen for other paired devices,
and if (a special) one becomes active it will automatically *switch over* to
it.

> No need to switch headsets between listening to music or other content

With what I described you would also not need to do that, but instead just a
press a button on the headset to make it switch to the next/previous
(active) paired device.

But yes, I would regard a setting in which the headphone will automatically
switch over to a more important device as a welcome addition to the manual
buttons.

Regards,
Rudy Wieser

On 2/14/2022 12:44 PM, nospam wrote:
> In article <sue1jn$q8a$1@dont-email.me>, Paul <nospam@needed.invalid>
> wrote:
>
>>
>> And the secret sauce is Bluetooth LE 4.1 .
>
> multipoint support began with bluetooth 4.0, aka bluetooth le.
>

According to a comment I found, the word "may" was added to
4.1. Whether this was an oversight, or a late-breaking
announcement, I have no idea.

Paul

In comp.mobile.android, on Mon, 14 Feb 2022 20:25:46 +0100, "R.Wieser"
<address@not.available> wrote:

>sms,
>
>>> Although I've never heard of headphones which will connect to several
>>> devices at the same time,
>
>I stand corrected ... a bit. :-)
>
>A quote from that first link you posted :
>
>"This doesn't mean that you'll be able to stream audio from both connected
>devices simultaneously"
>
>What it /does/ decribe is that it can keep listen for other paired devices,
>and if (a special) one becomes active it will automatically *switch over* to
>it.
>
>> No need to switch headsets between listening to music or other content
>
>With what I described you would also not need to do that, but instead just a
>press a button on the headset to make it switch to the next/previous
>(active) paired device.
>
>But yes, I would regard a setting in which the headphone will automatically
>switch over to a more important device as a welcome addition to the manual
>buttons.
>
>Regards,
>Rudy Wieser
>
All very interesting.

Thanks all.

In comp.mobile.android, on Mon, 14 Feb 2022 06:43:07 -0800, sms
<scharf.steven@geemail.com> wrote:

>On 2/14/2022 1:40 AM, micky wrote:
>> This is the essential part of a longer post (soon to be released at
>> major theatres).
>>
>> This relates directly to cell phones.
>>
>> So to turn off the built-in PC speakers I disabled them but no sound
>> comes from the Bose bluetooth hearphones even though they are still
>> listed as paired with the PC, although the phone also says that the
>> hearphones are paired with it!!!
>
>Paired but not connected.

Aha. I'm going to need a lawyer if I ever want to get a divorce from my
headphones.
>
>It's possible to do what you want to do, but you need Bluetooth
>headphones with "multipoint" capability, you can't do it with standard
>Bluetooth headphones.

So they actually make them! But they don't make Hearphones like that.
They amplify the ambient sound too, they only made one model, and they
stopped making that.
>See <https://phiaton.com/collections/earphones/products/bt-100-nc>.

Thanks. AFAICT, these are just headphones. The hearphones amplifies
the voices of people standing in front of you (and all the other sounds
too. Set it too high and the clatter of the keyboard keys can be a
problem.) And they also hav bluetooth.

But they are not sold anymore.

https://www.hearingtracker.com/news/alangos-behear-hearables-take-on-bose-hearphones

https://www.nuheara.com/news/iqbuds-max-vs-bose-hearphones/

There may be a third one, especially if neither of the two above have
the feature that you can replay the last 10, I think it was, seconds of
what you just heard. Not that I would use that much, but if neither of
them has it, there's a third product.