Volume control at the speaker?

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.

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

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

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Thus spake BoborAnn:

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?

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

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:

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

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.

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

to

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.

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

...Jim Thompson

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You've provided other BS swearing about the correctness of it and have been wrong. Your credibility slipped before this and stating 6 Mbit/s here confirms you don't know Jack.

to

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

.

**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.

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

I rather think it does no such thing.

Graham

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

Graham

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

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

Graham

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

residence to

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

to

whatever

-

I have

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

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