Volume control at the speaker?

[Paul Mathews]

With a careful choice of transformers, you can get excellent fidelity
with distributed audio. See, for example:

http://www.rane.com/mt4.html

However, I'd still vote for multiple amplifiers and/or digital
networking if it were my house.

Paul Mathews

 

[Dave Plowman (News)]

With a careful choice of transformers, you can get excellent fidelity
with distributed audio.

Transformers capable of handling the 'accepted' audio bandwidth for
driving speakers will be *extremely* costly.

However, I'd still vote for multiple amplifiers and/or digital
networking if it were my house.

Yup. Although a digital distribution will simply add to the cost.

 

[[email protected]]

Simple answer. Purchase a speaker selector switch at any electronics
outlet. The selector switch takes one pair of amplifier outputs and
spilts out the output to 4 and up to 8 stereo pairs. (it takes care of
the impedance problems).Home run the cable from each stereo pair of
speakers in each room to an 8 ohm stereo wall attenuator in that room
and then bring the cables back to the speaker selector outputs.
Fidelity is not normally a huge concern on room distribution since the
speakers are of medium quality to begin with and the music is typically
bacground type.

 

[DaveC]

Thus spake BoborAnn:

I did this in my home using NXG Impedance matching volume controls ( part
number NX-VCM80) which you can get on EBay for under $20 each this device
allows up to 8 sets of speakers to be connected to a receiver.It has taps
based on how many you are using which allow too to present a constant
impedance to the receiver. They have 12 steps of attenuation which is plenty
for me

Using this method, you still have to connect the constant-impedance volume
control units in series-parallel configuration so as to keep 8 ohms total
impedance across the amplifier's output, yes?
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC
[email protected]
This is an invalid return address
Please reply in the news group

 

[Laurence Payne]

You being in the UK, I presume you mean 240:100v line transformers, yes? In
the USofA this would be half that: 120:50v transformers, yes?

Nope. He's talking about 100v line systems for audio distribution.
As it's voltage based, not current based, you can set up a wide area
coverage and tap off power at any location. The speakers each need a
matching transformer and typically include a volume control.

 

[Paul Mathews]

Some folks spend more for their cables than the cost of good
transformers, so *extremely* is a relative term.
pm

 

[Keith Jewell]

There's also low-cost amplifiers of decent to good quality available
now, thanks to class D tech. The following is a good example,
audiophile puffery aside:

http://www.tnt-audio.com/ampli/t-amp_e.html

Plenty for any background music task, volume control on the front. Just
run line-level signals to it and you're good to go.

-Keith

 

[Tim Martin]

Is there a wireless solution to distributing audio throughout a residence to
8 rooms? Digital?

Yes, there is; you can have a central computer acting as a music server,
with a wireless ethernet network, and network music devices such as the
Squeezebox.

So, in each of the eight rooms you'd have speakers and an amplifier (or
powered speakers) and a Squeezebox. You could also have other devices
connected to the amplifier.

So you could have:

Mode 1: All eight rooms playing the same sound from their Squeezebox, with
the Squeezebox acting in multicast mode. The volume in each room would be
controlled by its own amplifier.

Mode 2: Some of the eight rooms playing the same sound from their
Squeezebox, and others playing diferent sounds from the music server via the
Squeezebox. Selection of music in each room is controlled by the Squeezebox
remote control.

Mode 3: Some of the rooms playings sounds from their Squeezboxes, others
playing sounds from local sources (eg, TV with line-out connections, or
their own computer.)

Now: there's no need to use wireless everywhere; you can use a mix of
wired and wireless connections.

The Squeezebox is one of the more expensive devices at £250 or so each. I
have a Netgear MP101, which now cost about £70, but can't do Multicast.

On the other hand, all these devices can do Internet radio. I've not looked
into it, but I suppose you ought to be able to set up your own Internet
radion statio within your home, so all your Netgear boxes could tune into
it. (Does anyone know how to set up an Intenet radio station for use within
their home?)

Costs for a basic quality system (YMMV):

Central Computer ... whatever
Central Wireless Ethernet hub ... £70

Per room Netgear MP101: £70
Per room amplifier: eg Richer Sounds Cambridge A1 £80
Per room speakers: eg Richer Sounds Celestion F10 £110
Per room leads, stands etc: £40

So I think you could get a basic system with reasonable quality small
speakers at £300 a room; and for an extra £50 you could get better
floorstanding speakers. And of course you can use different-quality
equipment in each room.

Don't forget, this is providing all the audio requirements in each room ...
central music, TV, computer, etc.

Tim


..

 

[Pooh Bear]

Simple answer. Purchase a speaker selector switch at any electronics
outlet. The selector switch takes one pair of amplifier outputs and
spilts out the output to 4 and up to 8 stereo pairs. (it takes care of
the impedance problems).

Pray - tell us - how does it do that - " it takes care of the impedance
problems " ?

I rather think it does no such thing.

Graham

 

[Pooh Bear]

Is there a wireless solution to distributing audio throughout a residence to
8 rooms? Digital?

Something similar to wireless computer networking...

Currently only at mp3 like quality. True16 bit linear pcm in stereo @ 44kHz
sampling requires something like about 6 Mbps of bandwidth.

Graham

 

[Trevor Wilson]

Pray - tell us - how does it do that - " it takes care of the impedance
problems " ?

I rather think it does no such thing.

**Some do. The switch boxes typically either perform an internal
series/parallel thing, and/or place a high power (typically) 2 Ohm resistor
in the path.

 

[Pooh Bear]

**Some do. The switch boxes typically either perform an internal
series/parallel thing, and/or place a high power (typically) 2 Ohm resistor
in the path.

I was vaguely wondering about that. Neither approach is a good idea for
fidelity though.

Graham

 

[Trevor Wilson]

I was vaguely wondering about that. Neither approach is a good idea for
fidelity though.

**Of course. My first post outlined the best approach.

 

[[email protected]]

Currently only at mp3 like quality. True16 bit linear pcm in
stereo @ 44kHz sampling requires something like about 6 Mbps
of bandwidth.

44,1000 ksamples/sec * 16 bits/sample * 2 channels = 1,411,200 bits/sec

 

[[email protected]]

44,1000 ksamples/sec * 16 bits/sample * 2 channels = 1,411,200 bits/sec

Sorry, that's:

44,1000 samples/sec * 16 bits/sample * 2 channels = 1,411,200 bits/sec

or

44.1 ksamples/sec * 16 bits/sample * 2 channels = 1,411,200 bits/sec

In any case, it's 1.4 Mbits/sec, NOT 6 Mbits/sec.

 

[Pooh Bear]

**Of course. My first post outlined the best approach.

Indeed and I agree 100%. At some time in the future decent quality wireless
links will become available using the 2.4GHz band using a method compatible with
IEC 802.11. I'm actually waiting for a certain company to announce its
commercial availability. Last time I checked it was being held up for ETSI
compliance issues.

Graham

 

[Pooh Bear]

Sorry, that's:

44,1000 samples/sec * 16 bits/sample * 2 channels = 1,411,200 bits/sec

or

44.1 ksamples/sec * 16 bits/sample * 2 channels = 1,411,200 bits/sec

In any case, it's 1.4 Mbits/sec, NOT 6 Mbits/sec.

That's the raw data rate only !

Now you have to add overhead for the frequency hopping stuff, handshaking, whatever
and redundancy for lost packets - and I've no idea how the data's encapsulated -
there'll doubtless be extra stuff there too. I'm not calculating this myself, I have
it on good authority from some guys who are developing the product. I was quite
surprised how much overhead is required myself actually.

Graham

 

[Jim Thompson]

Is there a wireless solution to distributing audio throughout a residence to
8 rooms? Digital?

Something similar to wireless computer networking...

Thanks,

I have some 2.4GHz wireless units that can send/receive video and
stereo audio... MATCO ASK-2008-TR

...Jim Thompson

 

[Rich Grise]

That's the raw data rate only !

Now you have to add overhead for the frequency hopping stuff, handshaking, whatever
and redundancy for lost packets - and I've no idea how the data's encapsulated -
there'll doubtless be extra stuff there too. I'm not calculating this myself, I have
it on good authority from some guys who are developing the product. I was quite
surprised how much overhead is required myself actually.

You don't have to use TCP/IP, and you don't need, or even want, lost
packet redundancy, at least not for streaming audio. If you need a
protocol at all, use something like UUCP.

Cheers!
Rich

 

[CJT]

That's the raw data rate only !

Now you have to add overhead for the frequency hopping stuff, handshaking, whatever
and redundancy for lost packets - and I've no idea how the data's encapsulated -
there'll doubtless be extra stuff there too. I'm not calculating this myself, I have
it on good authority from some guys who are developing the product. I was quite
surprised how much overhead is required myself actually.

Graham

Even accepting your numbers, a 10 Mbps link is adequate. So it's not
necessary to resort to MP3.