Voice Select Between Elk and Sound Card

[BraveSirRobbin]

Wierd that it is ok with a regular speaker and not with headphones etc.

No, the regular speaker was put in at Output#1 directly at the request of Spanky. It has nothing to do with the preamp output as it was connected to output #1 directly.

The pop sound is coming from the preamp output after the voltage divider resistors (refer to schematic). I can take headphones and connect them in place of the amplifier and the pop is there so I know it's coming from the pre-amp output of the Elk (i.e. after the resistor dividers).

I also tried a number of combinations with capacitors (values/shorting them/etc...).

 

[Spanky]

BSR,
Added info for your audio gurus. Output 1 is a push/pull output. Neither terminal of Output 1 ties directly to ground. Ground or negative is referenced internally in the audio amplifier.

 

[BraveSirRobbin]

BSR,
Added info for your audio gurus. Output 1 is a push/pull output. Neither terminal of Output 1 ties directly to ground. Ground or negative is referenced internally in the audio amplifier.

Ah, that could explain the possible reference problem with ground then. I was wondering why you went with the keypad ground ("NEG") and not the ouptut #1 ground.

I don't have anything connected to output #1's ground (as shown in the schematic above with "NC").

 

[BraveSirRobbin]

Hey Spanky;

I played around with this some more and here is what I did.

I set the global volume of Output #1 non-alarm voice to level six. I set the "Wav" and "Volume" levels of the PC sound card to maximum. I then could set the amplifier to a minimum gain (and still achieve the desired volume).

You can still hear the "pop" but just can't notice it that much now.

I think this will fly.

I will still try the isolation cable that I referenced above (mainly with the PC sound card as I get a squeal out of it that I think a ferrite bead or iso cable will fix. It is very slight also).

So I believe this method of combining the two sound sources (Elk M1 Sound and HA PC Sound) is a success and should work out. I'll know for real when I install this system in my buddy's house in a month or so (see if it gets his WAF approval!).

 

[Smarty]

BSR,
I have just experienced the same situation you described in this thread. Did you find out anything ADDITIONAL to minimize/fix this pre-amp pop?

I can minimize it in a fashion similiar to what you described.....was kinda hoping for a TRUE fix.

 

[BraveSirRobbin]

No, that's the fix I wound up using. I really don't know how else to fix this.

I think it will work out, and hopefully I'll get to this part of the install tomorrow.

 

[BraveSirRobbin]

Here is an update as I know a couple of people were interested in this.

I wound up NOT using the 10 microfarad capacitor as shown in the above schematic and played around with the volume level of the Elk M1 Gold.

The "pop" is not noticed during switching.

You will notice a difference in sound quality though (no fault of Elk's as it just doesn't have the processing power of the PC).

The only downside is you have to create a script to switch the relay anytime you want to have HomeSeer announce something. This isn't a big deal to me, but may be to some.

Overall I'm pretty happy with the results and the versatility that was achieved with this setup. :angry:

 

[Smarty]

Thanks for the update.

 

[IVB]

Did you find a 6.8K resistor, or did you string together a handful of smaller ones to build up to that? (is that possible?)

I had bought a mixer to deal with this when I had 3 sources, but now that i'm down to 2 I'm going to duplicate your setup. I'll also try not using the 10uF in the beginning

 

[Spanky]

The two resistors could be a 10K and a 1K instead of 6.8K and 680.

 

[BraveSirRobbin]

IVB:

PM me your mailing address and I'll hook you up!

BSR

 

[IVB]

Thanks for the offer, but if 10K and 1K work, i'll go get them from RatShack today; if it doesn't work, i'll PM you.

Also, Is it just me, or is the elk website down? I was trying to look up http://www.elkproducts.com/support/images/...evel_Output.gif , to get the diagram direct from them, but I can't even get to the home page.

I was trying to wrap my mind around the detailed wiring, is it:

Out 1 Plus->6.8Kresistor->
(path a) ->Positive Audio Input
(path ->680 resistor->splice with Databus Negative ->Negative Audio Input

Output 1 Minus->UNUSED

 

[BraveSirRobbin]

IVB:

The website seems down, but, FYI, the left part of my schematic was directly "grabbed" from that original document you linked to.

 

[AceCannon]

My plans include an Elk's announcements plus a PC sound card / CQC.

1. any reason not to use a mixer like this one?

2. any opinions on whether the Elk can drive eight of the 32ohm speakers with out an external amp?

 

[tmbrown97]

My plans include an Elk's announcements plus a PC sound card / CQC.

1. any reason not to use a mixer like this one?

2. any opinions on whether the Elk can drive eight of the 32ohm speakers with out an external amp?

Only issue I'd see with #1 is to make sure it's on backup battery with the M1, otherwise you wouldn't have your output 1 sirens if power was out (or fire alarms, warnings, etc).

As far as the SP12's, I believe spanky has commented a few times that that's exactly what they're for - so you can run up to 8 speakers off the M1 without needing another amplifier. Sound quality is nothing amazing but it gets the job done. I'm currently using 3 of them and have a couple more laying around for future use.