I didn't look inside of it, but when I connected more then one device, there was a slight buzz in the speakers. I tried to return it through ebay, but the seller didn't even want a hassle and just let me keep it. I guess its just a crappy device.
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How to use one set of speakers for multiple PCs?
- Thread starter tempest
- Start date
I didn't look inside of it, but when I connected more then one device, there was a slight buzz in the speakers. I tried to return it through ebay, but the seller didn't even want a hassle and just let me keep it. I guess its just a crappy device.
HoJoPo
Veteran Member
If there's no isolation between inputs, and a common ground connection, you could have had a ground loop between the inputs and the speakers. Was it a 60hz hum, like this? https://www.youtube.com/watch?v=SVZ2P0KsLic
That's assuming you're in North America, if in Europe or the UK it'd be a 50hz hum.
One advantage of an active mixer is that it will probably isolate the inputs better, preventing such a loop (if it's well constructed.)
Chuck(G)
25k Member
On that ABCD box that I linked to, note that the switch is multi-pole, so you do get complete isolation between feeds.
tempest
Veteran Member
I have access to a ton of boxes like that at work, but I lack the ability to modify them. Also, how would adding DE9s to it help? I need headphone jacks.
Chuck(G)
25k Member
Unless you want to open the box and hack the connections, it would seem to make sense to construct a bunch of headphone jack to DE9M connector cables, no?
Unless, of course, you don't have the desire or skills to make them, which is understandable.
Unless, of course, you don't have the desire or skills to make them, which is understandable.
tempest
Veteran Member
Lot's of work there. I think I'll try and win something like this: http://www.ebay.com/itm/272237285044
I suppose if I REALLY want to cheap out on this, I could get a bunch of stereo extender cables (male on one end, female on the other) and just plug the speaker into the extender cable of whichever computer I'm using at the time. It would look a bit dumb and not be very convenient, but it would work I suppose.
I suppose if I REALLY want to cheap out on this, I could get a bunch of stereo extender cables (male on one end, female on the other) and just plug the speaker into the extender cable of whichever computer I'm using at the time. It would look a bit dumb and not be very convenient, but it would work I suppose.
Chuck(G)
25k Member
You do understand that the eBay box is intended for low-level signals, don't you (100K pots)? So it'll be suited to "line out" type outputs, not speaker outputs. And you'll have a common ground between inputs at all times, which could make for some noise.
If that's okay, give it a try--isolation between channels tends not to be wonderful on these passive devices, however.
If that's okay, give it a try--isolation between channels tends not to be wonderful on these passive devices, however.
g4ugm
Veteran Member
Actually if we are talking noisy, horizontal slides are a total dust trap. No matter how good the seals, they still seem to go noisy over time. Nor is re-plugging cables a great idea. They tend to break where the cable joins the plug due to stress fractures. Just buy lots of really small speakers?
tempest
Veteran Member
I'm sort of surprised that this issue doesn't come up more often. I guess everyone just has multiple speakers or takes the plug out of each system when they're done.
Maybe I'm not being 100% clear on this, but only one system is going to be on at a time. I'm not switching between running computers. This is really only to save me the trouble of having to move the computers and unplug the cable each time I want to switch it to a different system.
Maybe I'm not being 100% clear on this, but only one system is going to be on at a time. I'm not switching between running computers. This is really only to save me the trouble of having to move the computers and unplug the cable each time I want to switch it to a different system.
It sounded kind of like that. Strangely, it would hum even if a second input device was turned off.
Since I only had two computer to connect, I ended up using a kvm switch which can also handle speakers. I think you can try something like that with more inputs, like a 4 port kvm. This experience made me realize that there is a reason that good audio gear is not cheap.
tempest
Veteran Member
True.
tempest
Veteran Member
Going back to the switchbox idea for a second. Would I get a ton of noise and interference if I used something like this? Honestly this may just be the easiest solution and I already have most of the parts.
g4ugm
Veteran Member
It depends on the quality of the switches, sockets and the patch leads and other cables. Personally I haven't had a problem with my Tandy/Realistic switches and I assumed anything for sale on E-Bay would be of similar quality. However where I have had issues was with the cheap 3.5 mm sockets used in laptops and clone sound cards. Some of the 3.5mm back to back patch leads are also terrible quality. put the two together and you end up with unreliable noisy connections.
Both the AV EBay items and my Tandy switches have phono sockets which in my opinion make a much better connection than 3.5 mm jack sockets. So long as you use leads with quality 3.5mm plugs on one end and phono on the other, not adaptors and so as long as the switches are not noisy I would expect no more noise than if you used direct connections.
Even better would be to dispense with plugs and sockets at the switch end hard wire leads of the correct length to the various PC's but of course this is less flexible...
Both the AV EBay items and my Tandy switches have phono sockets which in my opinion make a much better connection than 3.5 mm jack sockets. So long as you use leads with quality 3.5mm plugs on one end and phono on the other, not adaptors and so as long as the switches are not noisy I would expect no more noise than if you used direct connections.
Even better would be to dispense with plugs and sockets at the switch end hard wire leads of the correct length to the various PC's but of course this is less flexible...
tempest
Veteran Member
I haven't seen any switches with phono sockets unfortunately. Do you have any brands/model numbers?
I see some with RCA ports (which is what I have): http://www.ebay.com/itm/331854903605
And some with those old RF style connectors (which I assume won't work for crap): http://www.ebay.com/itm/131811305106
My switches are from the early 2000's and have S-Video/Composite video and two RCA stereo jacks. They work just fine for games, but I'm not sure how well they'd work for something like this.
I see some with RCA ports (which is what I have): http://www.ebay.com/itm/331854903605
And some with those old RF style connectors (which I assume won't work for crap): http://www.ebay.com/itm/131811305106
My switches are from the early 2000's and have S-Video/Composite video and two RCA stereo jacks. They work just fine for games, but I'm not sure how well they'd work for something like this.
Chuck(G)
25k Member
In all the years that I've known them, the RCA connector is a phono plug/jack. Wikipedia reference
What an "RCA stereo jack" is, befuddles me.
On the other hand, a (sub) miniature "phone plug" is not the same as a "phono" plug Wikipedia reference.
If you've ever had to work an old style switchboard, you'd never forget the latter. exempli gratia
What an "RCA stereo jack" is, befuddles me.
On the other hand, a (sub) miniature "phone plug" is not the same as a "phono" plug Wikipedia reference.
If you've ever had to work an old style switchboard, you'd never forget the latter. exempli gratia
tempest
Veteran Member
For some reason I was thinking that phono connector was a headphone jack type plug. I've always heard the other kind called RCA connectors.
By stereo rca jack I mean there's a R and L that make stereo rather than just one plug for mono sound.
By stereo rca jack I mean there's a R and L that make stereo rather than just one plug for mono sound.
lowen
Veteran Member
Classic ground loop. Ground loop isolators are available; not exactly cheap, though.
Good audio gear is indeed expensive; a Roland R-26, to use an example, is available for $378 to $600 (or even more, depending upon seller). But its inputs have the best sensitivity with the lowest noise of anything costing less than $1,000, with an input sensitivity of -70dBm for 0dBFS and a noise floor of -124dBm. I use one for a Shure SM10A that I have, which has a -65dBV/Pa (1PA=94dBSPL), or 0.45mV for 94dBSPL. The Roland is good for a sensitivity of 0.25mV for 0dBFS (dB relative to full scale). XLR inputs with 48VDC phantom, six track recording capability in a handheld.
For the OP's purposes, a relatively simple mixer would be fine, but watch the grounds. Pro gear is balanced in and out to reduce the problem, since then the ground (shield) is not used as a circuit conductor and can be opened on one end while being grounded on the other, maintaining shielding.
Chuck(G)
25k Member
My point was that if you want avoid ground loop-induced noise, that switching both the signal and ground might not be a bad precaution.
badmofo
Member
I have an use both the passive Rolls mixer, and the switch linked earlier with the Korean writing (only 2 outs on mine though).
Both work really well!
Both work really well!