I was so impressed by John Warner's Ocelot-based home audio that I decided to build one like it. I want to place PC amplified speakers throughout the house in zones corresponding to the 12 IR zones I have established (actually it will be one set of speaker for every two zones). I want to be able to mute the audio, simulate "distinctive rings" based on caller ID (if it's one of my wife's VIP #'s it rings one way, mine another, etc). I want to be able to pipe front door and speakerphone conversations through it as well.
My question is this: How do I switch all of the audio feeds through a SECU without inducing hum or sharp "snap" transients? What kind of cable should I run? Should I remove the amps from the speakers and mount them in the wire room and just have normal speaker wire going to the speaker boxes? What kind of relay would switch a 38W Sound Blaster speaker without burning itself or the relay out? Any ideas will be helpful!
Since you are using amplified speakers, the SECU16 relays will easily handle the line level (i.e. unamplified) audio that you need to feed the speakers. The 38W you refer to is the output of the amplifier in the speakers. Input to the speakers is a relatively low voltage (line level) like that put out by the sound card in your PC.
I use PC-style amplified speakers for my whole house audio and have no problems with buzz or hum even though some of them have 50 feet of cable connecting them. I use regular telephone cable (twisted pairs) for cabling and buy it in boxes of 1000 feet for under $30. I use the same cable for my PIR's and other SECU inputs as well.
So far, I have not tried switching audio sources with SECU relays but I may do that to switch from my SpeakEasy to my PC sound card so I can play MP3's from my PC on the same speakers.
If needed, you can double up on the pairs (I do this for powering my alarm horns with 12vdc from my wiring closet).
"John W" I use PC-style amplified speakers for my whole house audio and have no
It could be that you're just lucky not to have any hum issues. Unfortunately, I've already discovered I couldn't run one set of amplified speakers through 3 position RCA stereo switchbox without outrageous hum. I was trying to switch inputs from a small TV, a PC and a portable MP3 player into a set of amplified speakers and as soon as the RCA cable from the PC was plugged in, there was an outrageous hum problem.
I'm anticipating a number of devices feeding into the SECU audio switcher with the output going to at least 3 sets of amplified speakers. My gut tells me at least one of those combinations is going to hum if wired through twisted pair. But I can simulate it pretty easily with uninstalled CAT-5 pieces I have lying around before I go through the trouble of pulling cable. I just think the electrons in Canada behavior themselves better in audio systems. :-)
MP3's > from my PC on the same speakers.
That's where I think you might run into hum and crosstalk issues. Of course, I live within a few hundred meters of a big cell tower, so that might explain why hum is a bigger problem for me.
Twisted pair is not as good as shielded but it is cheap and what they connect telephones with. Given that same wire is capable of carrying a broadband signal (DSL) for several kilometers, it should (and, in my case does) handle line-level audio adequately. If you have any around, you could do some bench testing before installing anything?
RCA jacks/cables normally carry amplified signals so I'm not sure what you were switching? Line-level audio normally uses the 1/8" earphone style jack/cables like MP3 players and PC sound cards use. Was the hum 60cycle? If yes, it's probably a grounding issue between the devices your are switching?
Candadians do generally behave themselves quite well (even Canadian electrons ;-) but a test with CAT5 sounds like a good idea. Just be sure you are carrying the unamplified (line level) signal on it so the CAT5 goes from the PC soundcard output (example) to the amplified speaker input.
You may also recall from previous posts that all of my SECU relays connect to my relay board and are only used to switch these 10a DPST relays. This provides isolation and higher current carrying capacity.
???? On most of my stereo equipment, the red and white RCA jacks are used to connect line level devices. The only time I've seen RCA connectors carry amped signals was with an old, suitcase style phonograph player or are we talking about different things?
The switchbox had RCA style jacks for switching line level audio. I connected to it with a mini-stereo 1/8" phone plug to two RCA plug cables. And yes, it's probably a grounding issue and one that was impossible to solve. I ended up using a two sets of speakers and a mini-stereo extension cable so that I could connect and disconnect the PC and the MP3 player from speaker input manually.
Candadians? Are they the male of the species? :-)
My feeling is that there was a problem in the audio switchbox but another make and model behaved the same way. What the TV and the PC were using for their audio ground weren't compatible. As for testing, since I am a wood-worker by genetic disposition, the command "measure twice, cut once" has a counterpart in the electronics world. "Test twice, then hookup."
I am going to try John's suggestion to use ordinary twisted pair - at least I am going to test it with some spare wire remnants and the SECU.
FWIW, after a long period of no noise, my ESM1 is reporting a steady noise signal that lights up two bars of the display. I've also been experiencing intermittent operation of some devices that are at the ends of circuits. Since it's uniform on each one of the circuits, my only guess is that it's coming from outside the house.
I think the operative word in his post is "Power" relays.
Lots of relays are used to switch line-level signals (that's how telephone switching offices worked AFTER operators with jacks and BEFORE electronic switching).
The SECU relays are small reed relays intended for applications such as yours so should work fine?
wrt to the ADI forum - yes, the shortcomings you have identified are real...
In spite of its quirks, the ADI forum is very useful. It provides an excellent archive of information that goes back several years. Searching across topics would be nice and has been discussed in the forum but iirc, is a limitation of the software package ADI selected? Once you get used to it, you'll learn to love it - warts and all!
wrt development, ADI is a small company and HA is only part of their product set. A recent post by ADI asking what products are of interest leads me to believe we will see some new development soon?
IMO, even though the last update of CMAX is now a couple years old, there are still no other products available that come close to these in their flexibility and affordability...
Yes, I know that trick. But why should *I* have to compensate for their programming problems or poor choice of forum software?
My greater struggle is that "any time you come across a website with a crappy search interface" usually means there's something *crappy* somewhere in the company. The fact that they put up with their awkward interface for so long without fixing it is not inspiring. *They* could put a Google-based search box using the method you suggest on *their* site to compensate for their ridiculous "one forum at a time, please!" search engine but they haven't. Other sites do that, why can't they? Instead of useful search tools, we get to adorn our messages at ADI's forum with lots of nice smilies and emoticons while the basic requirements of an easy-to-use web forum go unaddressed. It embodies almost all of the things I dislike about non-Usenet forums.
I guess it really torques me that they are allegedly automation EXPERTS and they can't get their web page automated worth a tinker's damn!!!!! That's
*not* that kind of company I want to buy automation SW, HW or firmware from. "We know it's crappy, but we can't be bothered fixing it" is the attitude such I read from poor website design. From what I managed to glean from Google and elsewhere, it wasn't until Bryan Karras, as a vendor, started his own CPUXA forum that ADI got their act in gear to deploy one - they apparently had nothing up until that point. A *vendor* had to do their job for them. No warm and fuzzy feeling there, either, I'm afraid.
It's really put me off investing any more money in the ADI line of equipment. Couple that with Dave's comment that they "lost" the BX24-AHT that he sent them and a not-very-pretty paint-by-numbers image slowly emerges. No new products in 3 years, no RF input, no ASCII string matching as well as a host of other little "niggles" worries me. Dave Houston's one-man shop launches more products more often then they do and he's disabled! What's *their* excuse?
Considering I can buy a Pentium class mini-ITX for roughly the cost of an Ocelot I think I need to re-evaluate my system design. I'll always be able to find a replacement controller if I choose the PC-based strategy. On the other hand, things could get pretty hairy if ADI goes out of business. I keep thinking of the gentlemen from the UK who recently posted with his burned-out control board who'll have to redo his entire system because the specialized CPU board was no longer available. I think I might seriously look into the Elk line of products to see if they're hitting more of their marks than ADI. Although I can't find it with the forum search tool, I am sure that one of ADI's key technical people left. I'll bet he took a lot of "institutional memory" with him. That's a worrisome problem in a small company. It's caused more than one such shop to shutter their doors.
For the things I am trying to do, I'm becoming more and more convinced that a mini-ITX PC is the proper way to do it instead of the Rube Goldberg-ish method of converting RF to IR to X-10 and torturing myself with ladder logic programming to work around the shortcomings of the Ocelot. For a device that's strongly oriented towards X-10 NOT to have some sort of X-10 RF interface (especially when Dave even dumped on e in their laps!!!!) is just bogus. There's no other word to describe it. They've fallen asleep at the wheel, I fear. [/flames off]
"John W" wrt development, ADI is a small company and HA is only part of their product > set. A recent post by ADI asking what products are of interest leads me to
I know in my many trips round and round the ADI forum maze that people have been offering suggestions for a long, long time. Aren't they three years late? A dozen other companies have been putting their new protocol units out for sale and ADI is *thinking* about some new stuff. Danger! Danger! Will Robinson! There seems to have been a precipitous lack of focus on the Ocelot/SECU/Bobcat in recent times. People have been asking for two-way serial Bobcats for a while, they've also been asking for RF.
I'm sorry to be so negative but when I see a website limping along like theirs I just have to re-evaluate my willingness to commit to buying $1000 worth of their equipment. I'd feel that I would have to buy a complete duplicate set just to insure that ADI doesn't lose so much interest in the Ocelot/SECU line that it folds leaving me without a source for spares.
Don't take any of this personally, please. You're ADI user 27, I'm #1402. You've had a lot more time to acclimate! My wounds from their wretched website are still bleeding! :-)
I have to jump in here to defend ADI. Being a wizard on imbedded system design doesn't make one a wizard on HTML or JAVA. They are different skills. And I would rather have someone who focuses his full effort on hardware designing my automation equipment.
Our Ocelot runs 24/7 week after week with no glitches. That is expected of industrial automation equipment, which is where the Ocelot came from. People here talk about X10 not being reliable. I would never trust my automation to a PC running 24/7, at least not using any M$ software more complicated than DOS.
Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.