A/V Switcher

[bh00]

Hi,

I'm looking at building a DIY A/V Switcher built around some MAX4456's for video and 4052's for audio.

I was wondering what you'd all want if you were building this switch, suggestions for features I might want, etc.

So far I'm going to have 8 S-Video inputs and 8 S-Video outputs in an 8x8 matrix (any input to any output) and serial control. Also, the audio will be 16 stereo inputs, and 12 I think, stereo outputs. the first 8 of each being tied into the 8 video channels.

I just wonder how you'd expand on that? Would anyone ever think about 'purchasing' one so to speak?

Ben

 

[huggy59]

It's been done, I believe. Smee has developed a switcher, but I'm not sure if he was interested in making it a kit. I think he's got it working with Ethernet conneciton under a web page for control, among other capabilities. Smee?

 

[rocco]

I have plans to do the same thing, but with one addition. I'm also adding 8 stereo/video modulators to put the eight inputs onto eight consecutive UHF or cable channels (using a total of 10 channels, when you count the blank channels you should leave before the first and after the last). I just need a good design for an active, tunable filter to remove any incoming channels in the selected frequency range.

Maybe we could pool designs . . .

 

[BraveSirRobbin]

What are you going to do about volume control and controlling your sources? Will each source have its own amplifier?

I was thinking about doing this with an 8x8 multiplex device HERE and possibly have each zone have a controlled volume control (possibly combined with amp) unit HERE.

Problem is I am scared to death buying ANYTHING from that company as their documentation and integration instructions seems flaky as all get out (if available at all)! Shame to because their matrix switch seems reasonably priced.

If you have a source better than this one let me know!

I was also thinking about using these amplifier kits HERE ($30 per zone).

 

[Rupp]

BSR,
I'm in the same boat as you are. I want to buy the AVS 8x8 as well but the lack of documentation bugs me. Could the AVS 8x8 be used to switch cameras as well sound?

 

[BraveSirRobbin]

Yes, it will switch video as well. They must have an excellent customer base because they don't seem to be interested in drawing new ones!

 

[Skibum]

Get the ASEL Pro , not the 8x8. The pro allows for independant switching of the audio and video.

 

[smee]

I didn't check the board yesterday. Figures I'd miss a topic that I've spent a lot of time on recently.

As mentioned above, I've been working on my own version recently. It's fully functional and connected to my "system" now - even though I'm making some revisions and will have to take it out of service soon to "finish" it.

Mine is set up to switch composite video. All of the devices I'm connecting to take composite inputs (TVs, computers, small LCD displays). Not even my living room TV has anything other than a composite input. That being said, if I need to switch svideo, I should be able to use two composite channels.

I have 16 composite inputs and 8 composite outputs. I'm using two max4456's to do this.

There are 16 audio inputs and 16 audio outputs (16x1 or 8x2 in and out). They are all individually controllable and selectable (16 mono, 8 stereo, or any combination of the above). I'm using an Analog Devices AD75019 for the audio switching. This is a 16x16 analog crosspoint switch.

The core PC board is set up for serial control. I used this for testing. In the current installation, I'm using http-based control. I have another board running a simple web server that receives URL requests and makes the appropriate changes. I'm working on finalizing this software - but I've had very little incentive since it's working so well and I'm using it now.

The switch board and the ethernet board are both using Atmel AVRs.

I've attached a picture of the inside of my box showing the power supply and switch board. The ethernet board is not in this picture, but sits behind (above in the picture) the power supply.

 

[Skibum]

That is a nice bit of kit there Smee....

Looks like you have quite a bit of time into it. Was it worth the time, or do you just enjoy the whole kit aspect? What about costs?


Really impressive!

 

[smee]

I was also thinking about using these amplifier kits HERE ($30 per zone).

For zone amplifiers, I'd seriously consider the Sonic Impact T-Amp. It looks and the ad copy sounds like it's a toy, but it gets really good reviews on a lot of the audiophile web sites. With a good power supply and efficient speakers, the sound quality is supposed to be ridiculously good.

I have not tried one yet.

Sonic Impact T-Amp at www.partsexpress.com
Sonic Impact T-Amp at www.ecost.com

These amplifiers were almost impossible to get for several months.

If I were setting up multiple zone audio, I'd rig something like this:

Audio Source -> Switch (see above) -> Line-level volume control -> amplifier (T-Amp?) with fixed gain -> speakers

I like the idea of controlling the signal at the line level instead of after the amplifier but I haven't experimented much with it yet. One of my backburner projects is a remotely controlled volume (etc.) control, but I don't need one so I haven't built it yet.

 

[smee]

That is a nice bit of kit there Smee....

Looks like you have quite a bit of time into it. Was it worth the time, or do you just enjoy the whole kit aspect? What about costs?


Really impressive!

I try not to think about how much it cost. It was certainly more than the level of the hardware we usually discuss - things like the ASELs for $150 and the AVS8x8 for $200. The audiophile/home theater guys look at $1000-$2000 units.

I haven't added up the costs, but it was probably over $300 including having circuit boards made. I think the rackmount case, alone, was $70 but it's a nice solid enclosure with a brushed aluminum front panel.

It was definitely worth the time. It has the features I wanted and I like designing and building stuff. This was something I've wanted to do for years.

 

[BraveSirRobbin]

Get the ASEL Pro , not the 8x8. The pro allows for independant switching of the audio and video.

You mean the AVS 8x8 will not switch sources and outputs independently like a true matrix switch? Also, I can't find the unit you were mentioning on their website.

What I am trying to do is create a "Poor Man's" version of a Russound Cav6.6. To do this I was trying the following methods:

Six Sources -------> AVS 8x8 -----> Independent Amplifier/Volume Control on all eight Outputs to eight stero zones

The idea would be to control the six sources, the AVS 8x8 and the Volume Control remotely either by IR or serial port/Main Lobby or a combination of both. I was thinking about experimenting with Buffalo Electronics IR distribution equipment which is now carried by Automated Outlet.

Smee was suggesting controlling volume via line level rather than by amplified, which could be done here, depending on what I would use on the output side for volume/amplifier products.

I was hoping that Home Automated Control Systems products could be used, especially for the independent volume/amplifier needs, but like I said before, their website leaves a lot to be desired for getting any product information or system integration methodology. Shame to because if I could get this going I believe a LOT of people would look towards this method in lieu of getting a more expensive Russound system (the cost of a Cav6.6 is over $3,000).

I am not knocking Russound's product, it is an excellent one and I love the keypad integration is provides, its just out of my price range at the moment.

I would really enjoy someone who knows these products to suggest how to integrate and various options one could obtain using HACS products (anyone, anyone he says in the Ferris Bueller teacher voice).

 

[smee]

Get the ASEL Pro , not the 8x8. The pro allows for independant switching of the audio and video.

You mean the AVS 8x8 will not switch sources and outputs independently like a true matrix switch? Also, I can't find the unit you were mentioning on their website.

I believe the AVS8x8 treats (1 composite) and (2 audio) inputs as a single logical input. The same on the outputs. They must all be switched together. I believe this is the case from looking at the command structure.

So you can't do something like Composite Input 1 and Audio Input 4 going to Composite Output 3 and Audio Output 3 (i.e., you can't mix and match). That is something I can do with my system and that can be done with the ASEL units. For many people, this won't be particularly useful anyway.

I see it as, among other things, a way to run music (from a common "background music" input channel) over different video - picture frame/slide show, security camera, etc.

The ASEL units have a maximum of 2 outputs. In order to build large matrix behavior, you will need multiple ASEL units and maybe some distribution amplifiers on the inputs, etc. It will add up quickly. I think you would need 2 just to get full A/V (composite and stereo audio) from 8 sources to 2 outputs.

By the way, this is not meant to knock the ASEL units at all. They seem to be very good hardware and a lot of people are happy with them. I have one of the 4x1 A/V selectors from the same company and it works very well (my control script is posted on the HS forums). I'm not using it at the moment since my switch is able to do everything I need. The ASEL units serve a different function than a crosspoint - you should get whichever is right for your application. If you need more than one or two outputs, the right one is probably a crosspoint.

 

[smee]

Here are some pictures I made for a thread on the HS board (HACS volume controls on HS forum) showing how the HACS switch and volume controls could be used for an application like BSR's.

Line level volume controls would appear before the amplifiers (replacing or supplementing the speaker-level volume controls after the amplifier). Depending on how zones are created, using line-level control may require you to use an separate amplifier for each zone.

 

[smee]

And the setup in use: