Projector sound problems

[madder]

Hi, I just bought a mini projector. It comes with VGA and AV sockets as well as SD card and USB sockets. The idea is that I can plug a memory stick or an SD card into it and play media from there in MP4 format. I was hopeful that there was a way to connect the device to my external virtual 5.1 surround sound card and that way get surround sound through my speakers. But that doesn't seem to be working out. First of all, my external virtual 5.1 sound card connects to my laptop via USB and that works fine, but when I connect it to the projector via USB, it doesn't work. I am under the impression now that the USB and SD sockets are for playing media only. So my next attempt was to try the line in feature on the external sound card. It's a 3.5mm input. I connected a cable from there to the projectors AV socket(which didn't work) and then to the projectors headphone socket, which didn't work either.
I have come to the conclusion that I only have 2 options here:

1. If I want to watch movies from USB or SD card, without the need for my computer as a host for the sound, I will have to use Stereo Speakers and connect them to the Headphone socket.

or

2. If I want to have surround sound through my projector, I will have to connect via my laptop using VGA to VGA or Laptop HDMI to VGA, while keeping the external sound card connected to the laptop via USB. It just all seems messy with cables everywhere?

Can anyone confirm if I am right or can anyone suggest some alternative solution. Cheers.

 

[Lucid]

I'd agree with most of your findings. People often misunderstand socket directionality. However, I'm surprised the projector headphone socket didn't work.

Have you tried headphones in it when playing a media file? Also check if the socket needs to be enabled in the pj menus and that you have the volume turned up. If it works with headphones then it sould also work when connected to the soundcard's line in. Once again, check the soundcard menu settings. Mic and Line In sockets are often disabled or muted because they are a source of noise when nothing is connected.

 

[madder]

I found 2 phono sockets on the back of the surround sound woofer. So I came out of there, into a Y cable 2 into 1 and then into the headphone socket on the projector. There's a button on the woofer which pushes in and out. When I pushed it in, the sound came through the speakers, but it didn't seem to be in surround. This technique, I suppose avoids the external sound card and just uses the speakers directly. But like I say, it doesn't seem to be in surround this way. I have gone into the projector sound settings and there are 3 options. Surround off, Surround and Trusurround. I find trusurround gives me the loudest and bassiest sound, but I am still not convinced that I am getting all of the speakers. My external sound card must have a way of doing this, right? Although I cannot adjust it's settings unless i use the laptop, and I'd really prefer to keep the laptop out of the equation. I was hoping the line in on the soundcard would work, but so far, it hasn't. And it is only a 1 x 3.5mm jack socket.

 

[Lucid]

You clicked the Thanks button! That's very much appreciated. Thank you

At the moment we here are working in the dark because you haven't given the makes & models of the gear you are using. Ordinarily we have a quick look at the online manuals (if available) and then try to post something specific to the gear you have. The best we can manage at the moment is some general help based on what typically happens with similar gear.

First off, surround sound:

Proper discrete 5.1 surround is made up of six individual channels for sound. So it needs some way to get those 6 channels from the source to the speakers. Tower PCs use 3x 3.5mm stereo jacks. There are two channels on each so that gives us 6 all in. A 5.1 PC speaker kit has a corresponding set of 3x stereo jacks. All the processing and decoding is done by the PC sound card. A typical budget PC speaker kit is kind of dumb. It just amplifies the sound rather doing anything fancy. A speaker kit might have extra inputs. If there's a stereo input then in most cases you'll only get sound from two satellites and the sub.

Better kits will include some form of pseudo-surround. A stereo input will make all the speakers work. It's rarely anything as good as Dolby Pro-Logic because of the cost of licensing.

Have a look in your speaker manual to see whether your kit does pseudo-surround or not.

Digital connections for audio are mainly Optical, coax and HDMI. These connections can transport a signal that has full discrete 5.1 surround sound. If the speakers or soundcard have digital inputs then they decode the bitstream data.

Although optical and coax usually looks like this they can also take the form of a 3.5mm jack connector, but only if the socket itself supports that feature. A simple cheap adapter or cable won't change digital to analogue or analogue to digital. In other words, if your projector has a Line Out/Headphone socket that is analogue only then the best sound you'll get from it is stereo. What happens to that stereo signal then depends on the speaker kit rather than the projector.

This brings us to the projector audio modes Off/Surround/TruSurround.

Despite their names none of these give multichannel surround sound. For a start the output jack is stereo, so it can't be anything more than a left and right stereo signal. "Surround" makes a basic stereo signal sound like it occupies more space. TruSurround is for taking 5.1/7.1 encoded sound and reducing it down to stereo but maintaining some of the impression of surround through stereo speakers or headphones.

I haven't come across many external soundcards that can work standalone without a PC. If only for power, they all seem to need a PC connected somewhere.

 

[madder]

All of that info is very helpful, thank you. The initial idea was to leave the Laptop out of the equation. My laptop, while good high spec Toshiba Satellite, does not have the ability for surround sound from it's board. So I bought a cheap external virtual 5.1 sound card like this:

And that worked by connecting via USB to the laptop. That worked quite well actually. So, then I was thinking that it would be great to have a small mini projector to play movies on and try to get that hooked up to surround sound without the need for the laptop. Again, it was a cheap mini projector like this one:

I also have an old PC type speaker system. Sub woofer and 5 surround speakers. The laptop must have been powering the soundcard via usb as well as allowing me to connect to it. I would take the 3 cables from my woofer and plug them into the external sound card and then into the laptop via usb. But without the laptop to power the soundcard I'm kind of stuck from that perspective. There are, like I said earlier, 2 phono sockets(red and white) on the woofer, which I can plug into. Once I do, I press a button and make those sockets live and then via Y cable I plug into my headphone sockets and it is ok. Not great, but ok.

The projector does have AV socket and VGA socket, but I do ot have a VGA cable, and when I tried the Y cable into the AV socket from the speakers, it didn't produce any sound at all.

I think I have to run with what I have or else invest in a powered external soundcard, or else use the laptop in the flowchart!!!

Thanks for the help.