Amp or Speaker Points?

[HAS]

Looking for some advice and experiance....

I have a new constuction install (about 6 months old now) that I installed a Cat6 network and there are 8 Ethernet Speaker Points on the same network. No problems NOW

The Client now wants an additional audio zone. I'm concerned about adding another Ethernet Speaker Point

Here's the questions:

1) Has anyone had more than 8 Speaker Points on a network? Any issues?

2) If I remove 4 Speaker Points from the system (in a rack in the Lower Level) and replace with a C4 Multi-Channel Amp, can I stream to multiple zones from the Cat5 input on the C4 Multi-Channel Amp.

3) or.... Will I need a Audio Matrix Switch? Can I stream to multiple zones from the Cat5 input on the C4 Audio Matrix Switch?

Thanks for your help!!!

Mark

Home Automation Solutions

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Mark Ingham

Superior Solutions Audio & Video / Home Automation Solutions

http://www.SuperiorSolutions-HT.com

[Samer Shami]

The answer to (2) and (3) is a "No". The Control4 multi-channel amp and audio matrix switch do not have the ability to receive MP3 streams on their ethernet connection. You will need to input analog RCA connections from the MC or HTC into the back for proper operation. This means a limit of 2 MP3 streams with HTC and 3 MP3 streams with MC.

Although I have no experience with point (1), please note the magic number of 7 different MP3 streams per single MC or HTC. Now you can have more than 7 different speaker points or mini-touch screens (as you have just proved!). It just means that some of them will have to listen to the same session that other units have started in order to keep the number of streams equal to or under 7. Having more than 7 units means that your limitations become one of bandwidth.

If you were to play the same session across 10 zones, and assuming that the controller does not multi-cast the session*, and assuming we are streaming a 320kbps MP3, then my dodgy math would go something like:

1) Each MP3 would take 320kps of bandwidth to stream**. We should also add a conservative overhead of 20% to account for any network issues. Therefore single stream is 384kbps.

2) In total, the 10 streams would take 3840kbps. Add some more overheads and lets assume it takes 4000kbps (because it is such a nice round number OK).

On a 100Mbps network, lets say 60Mbps-70Mbps is a realistic throughput. These 10 streams are going to take at maximum 7% of the useable bandwidth. Browsing the Internet via cable is limited to 6Mbps (here in Australia anyway), so you still have a fairly decent amount of wiggle room. The bandwidth leech is when you start transfering files around the network. Windows will always go full speed ahead when it comes to this, and will no doubt want to take all the bandwidth it can possibly take.

So, do you like how I took a simple question and obfuscated it with useless information? Ultimately, the network should be able to handle another speaker point. Copying files between computers is the ultimate bandwidth hog, and if there is an opportunity to segregate C4 traffic away from the PCs in the house, you shouldn't even have this problem.

*Multicasting a TCP/IP signal means that all 10 zones will be consuming the same bandwidth as 1 zone. I cannot determine whether Control4 uses multicasting or traditional point-to-point communication when it comes to streaming audio. Since I cannot determine this, I decided to use the worst-case scenario.

** Assuming that the MC or HTC actually streams out in MP3 format and not some other more bandwidth intensive protocol like PCM.

[HAS]

Now I'm a little worried about larger projects.

The C4 Equipment doesn't limit the qty of audio streams I can send out of a Media Controller. I have sent out 9 different streams at the same time without issue (8 Speaker Points + the Home Theater Analog Stream.

1) I would believe that If I am playing the same Session to 10 Speaker Points, if compression is 192 kb, I am only streaming (roughly) 200 kb out of the Media Controller and not 2 Mb correct?

2) If I am streaming 10 different Sessions, if compression is 192 kb, I am streaming (roughly) 2 Mb correct?

Since there would be no problem with Bandwidth on a 1 Gigabit network, now were talking about the limitations of the Media Controller architecture to stream more than 8 digital Streams off the harddrive.

Bummer about the no-go on the the Amp & Switch. That sucks.:/

[Samer Shami]

Since there would be no problem with Bandwidth on a 1 Gigabit network

I wouldn't say that. Control4 only runs at 10/100 speed, and even then will not have anywhere near the capacity to load the network running at 100Mbps speed. This is evident by the long time it takes to copy files to its hard drive.

If you start playing 9 different digital sessions you are on your own. If it works, all the best to you. If the customer complains of spotty playback, you can't really complain because you are exceeding the recommended limit. I am not saying this as an insult. Just appreciate you are going above recommended manufacturer specs.

Now in my opinion, the number 7 is not a hard and fast limit. I think it will vary depending on the MP3 bitrate you are trying to playback. Higher bitrates with VBR will no doubt limit the number of different streams you can achieve - and 7 seems to be a fairly conservative cap based on this. I feel if you tried to play back 64kbps MP3, you could easily exceed with 7 streams without any trouble (my opinion only!).

In answer to (1) - I cannot say. If it is using multicast IP, then it would indeed take 192kbps. If it is using point-to-point IP addressing, then it would take 2Mbps. I have not delved deep enough to determine which one it uses.

Answer to (2) is a little more than 2Mbps. I would estimate somewhere within the vicinity of 2.5Mbps to allow for overheads.