AirTunes Capability

[jimjiminyjim]

Does anyone know if AirTunes can play on multiple speakers at once? If I'm going to get some control over my music in the house, and want all the control!

Say I'm cleaning up the office and the bedroom at the same time, and I'm wandering back and forth. If I have Two AirPort express units, would AirTunes allow music to play on both at the same time?

[DVDSP]

...by a rep at the Apple Store at Westfarms. He said you can only choose one set of speakers at time, currently, according to the information he had (which, by his own admission, was limited).

Sorry. I was hoping for the same thing...

[stoid]

Turn up the sound on the speakers when you are in the other room! ;)

Maybe in iTunes 5? in iLife '05? Out January 2005? Sorry pal.

[jimjiminyjim]

Well, if the sales rep is right, I hope that in future versions support for multiple streams will be added. How much bandwidth would a single stream use anyway? 128kb/second I guess... that should leave plenty of room for multiple streams. Why wouldn't they make that a possibility? Seems silly to me.

[dvdh]

How much bandwidth would a single stream use anyway? 128kb/second I guess...

I sure hope it supports higher bandwidth that 128kb/s. If not, I can't really see it sounding good enough to stream to a decent stereo system.

[dermeister]

...here goes:

When you have a song with a 128 BITRATE, thats 128 BITS per second.

8 bits make a BYTE. Thus, 128 bits/sec = 16 bytes/sec...

So what you need is really very little...

[clr900]

I wonder if you have two computers if you can broadcast to two different rooms and just play the same song. There doesn't seem to be a reason why this wouldnt work, but it would be kind of awkward, however it could be good for other purposes if someone wanted to listen to something else in a different room etc.

[jimjiminyjim]

Thanks for the clarification on the bits/bytes.

Getting the timing right for playing two songs on two computers would be a little cumbersome, me thinks.

[DVDSP]

Getting the timing right for playing two songs on two computers would be a little cumbersome, me thinks.

"OK HONEY! GET READY TO CLICK PLAY IN 3...2...1....CLICK IT!"

Mmm, I think not.

[jimjiminyjim]

"OK HONEY! GET READY TO CLICK PLAY IN 3...2...1....CLICK IT!"

We've tried that... and always end up with a reverb effect. *sigh*

[seamuskrat]

I am sure its a matter of software tweaks and a possible function to be added later.

Of course, I am sure many of the buyers of this product do not have zones speakers in their house. Its a cool idea and concept, but the mere ability to have stereo to Mac connection is enough.

[JFreak]

folks, don't get confused :) the bitrate means the ENCODING bitrate, in other words, how much the audio FILE can consume data. that is one thing, and whole another thing is what the actual audio WAVEFORM that needs to be streamed will consume. you didn't expect that the DECODING would happen in airport express, right?

ok, so here it goes. stereo audio stream has two channels, each channel is sampled 44100 times a second, and each sample consumes 16 bits (or 2 bytes, whatever). 2 * 44100 * 16 = 1411200 bits per second, or 172,265625 kilobytes per second.

that's exactly 1x cdrom speed :)

[johnnyjibbs]

...here goes:

When you have a song with a 128 BITRATE, thats 128 BITS per second.

8 bits make a BYTE. Thus, 128 bits/sec = 16 bytes/sec...

So what you need is really very little...
Just a correction ;)

You are correct in that bitrate refers to the number of bits per second. However, AAC standard bitrate is 128 kbps (128 kilobits per second) which is 128000 bits per second. Still small compared with the 54Mbps (or 54 million bits per second) allowable by the 802.11g Wi-Fi standard. You are right about the difference between bits and bytes though.

To answer someone else's question, you are not limited to 128kbps. Apple's website says that it uses the Apple Lossless Codec to stream CD-quality (presumably AIFF) over the airwaves. That in part explains why the Apple Lossless codec was created in the first place (new for iTunes 4.5). iTunes must be able to convert AIFF to that codec in realtime therefore. However, AAC or MP3 files are much smaller than AIFF files and so they will not need to be converted.

Why would you want multiple streams anway? Currently iTunes does not support playing more than one song at the same time. If you need two streams, you presumably need 2 computers with iTunes and 2 AirPort Express basestations.

EDIT: JFreak, you're right. I'm also slightly confused, although what I have said above is still correct (I think!).

[wordmunger]

I believe you could do this sort of thing with a product like this. I'm not sure whether or not it would interfere with your airport signal, though:

Wireless AV transmitter (http://www.smarthome.com/7656.html)

[jimjiminyjim]

Why would you want multiple streams anway? Currently iTunes does not support playing more than one song at the same time. If you need two streams, you presumably need 2 computers with iTunes and 2 AirPort Express basestations.

If you want to clean house, or have a habit of wandering, you'll find yourself in different rooms. I want to have Crash Test Dummies playing all over the house while I'm spring cleaning. So that means I want an airport express connected to the living room speakers and the bedroom speakers (two airport express stations). That doesn't mean there needs to be multiple streams. It means that AirTunes should be able to tell *both* airport express stations to pass the stream on to their corresponding speakers - at the same time.

[crazzyeddie]

I think you guys are all wrong with the bandwidth needed. The transmission uses Apple Loss-less Encoding, so it will be approximately 1/2 the bandwidth needed for a 1x CD/AIFF file. In my tests, that 1/2 number was actually more like 2/3 the original AIFF file off of a CD. So just figure out how much bandwidth would be needed. From JFreak's calculations, that would be 172KBps ÷ 2 = about 86KBps or 0.672mbps (yes, megaBITS). So, thats about 1/16th the theoretical maximum bandwidth of 802.11b (aka Airport), or about 1/80th the theoretical maximum bandwidth of 802.11g (aka Airport Extreme).

If you assume 2/3 instead of 1/2, you get 118KBps or 0.93mbps.

[Sabbath]

I think this is a feature to expect in the future, it can't be too hard for Apple to get done can it. It would allow them to sell multiples of the same product to the same person which is always going to be a good thing, in an industry with such high research costs. Maybe this will be an incentive for us to up-date to iLife '05

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[zv470]

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[vashim66]

I don't know why anyone hasn't mentioned Squeezebox before.

http://www.slimdevices.com/

My brother has had this for a year or two and it beats Apples offerings on almost every aspect.

From their website....

"Digital and analog RCA outputs connect Squeezebox to your home theater, stereo receiver, or amplified speakers. And when you install multiple players, they can play independently or in sync for whole-house audio."