Unable to get good signal to noise ratio - what's the issue?
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ecc83
Well-known member
Ha ha! Not quite! Perhaps you would all like a rundown on the setup?
The garden is very small, 1x10mtrs or so (and a total mess at the moment. Wife loved her garden and would spend hours in it. Sadly no longer so able. I do not have the enthusiasm, energy or time) .
Cameras, two. Cheap, 50quid Maplin jobbies but one has lasted over 3 years. Paint is peeling of but still works. These feed thru a bedroom window sill to a RCA to CAT5 balun box (CPC/Farnell) round the bungalow network to the living room where another balun sorts them back to composite video. Into a 4 channel "security" recorder (not the best buy. I shall do different as and when I can) The single video output goes to an active splitter and thence to the vid inputs of a Panasonic Freeview HDD/DVD recorder. Also feeds a Sony Bravia 32 TV.
Sound path: Two mics as mentioned these feed a Behringer Xenyx 802 (has run 24/7 for at least 3 years!) which drives the audio side of the CPC balun boxes. Uball'ed again at telly end to feed security recorder which feeds vid/audio splitter.
Thus, poorly wife is able to watch the antics of birds, squirrels and other wildlife from the comfort of her sofa! All in "StereoPhonic Sound"!!
I shall dig out some twitterings for you to hear.
Dave.
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dyermaker8
New member
The info provided leads me to want to point out a couple of things.
1. Unbalanced = inexpensive consumer audio ; Balanced = Pro-audio. If your not using pro audio level gear don't complain about signal quality.
2. To fix this problem either A: Get a better mic B: get a balanced/unbalanced converter box.
1. Unbalanced = inexpensive consumer audio ; Balanced = Pro-audio. If your not using pro audio level gear don't complain about signal quality.
2. To fix this problem either A: Get a better mic B: get a balanced/unbalanced converter box.
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ecc83
Well-known member
Bit harsh? The OP has done everything right. Ok, cheap mic at $30 but not the cheapest you will find by a long chalk. It IS a Shure and purports at least to be balanced...I was fooled and I have been "at it" best part of 50 years!
Plugging an unbalanced mic into a transformer box is unlikely to improve things. The output of the mic needs to be clean and balanced.
But...FFS can somebody get a digital guessing box on that effing mic? PLEASE!
Dave.
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dyermaker8
New member
Sorry, It's not my normal self. It's a strange reaction that occurs whenever I see the word karaoke.
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RockDiedin2005
New member
Thank you. This is the odd part - the mic has universally good reviews online, and it's still 3 times more expensive than the cheapest brand-name dynamic mic out there, in case any gear snobs want to assume it *must* be due to the low price..
Also, I still haven't seen anywhere mention that the mic itself sends out an unbalanced signal. Something tells me that's unlikely. The first connection is XLR. If the insides of the mic cancel out the balanced signal, what would have been the point? I believe Shure included an XLR-TS cable 1) to make it easier for non-pro consumers to connect it to their karaoke boxes or computers, and 2) to differentiate it from their mid-level products and prevent the loss in profit that'd follow from pro users going for the cheaper option.
I searched, but could not find any examples of microphones with native unbalanced electronics inside. I also could not find any mentions of noise being introduced to balanced cables when connecting between unbalanced gear. If some examples/info are out there, please post it.
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ecc83
Well-known member
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dyermaker8
New member
Not trying to be a mic snob here,. I love cheap stuff. Just trying to look at it from a right tools for the job perspective.
Op has already stated that the problem goes away when he uses the supplied cable.
The SV100 is rated at 600ohms impedence, is supplied with a HiZ cable, and is marketed to be used with consumer level gear.
Op has already stated that the problem goes away when he uses the supplied cable.
The SV100 is rated at 600ohms impedence, is supplied with a HiZ cable, and is marketed to be used with consumer level gear.
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ecc83
Well-known member
The cost of a microphone has absolutely no bearing on its ability to deliver a quiet signal, so long as it is balanced it should be as good as one 3 or 4 times the price (tho' not many have the humbucking ability of the SM7b) . As I mentioned at the top of the thread, the SV100 is specced' as having about 6 dB greater sensitivity than a 57 so signal should not be a problem.
I might have to order one and rip it apart!
Dave.
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dyermaker8
New member
I double dare ya dave.
bouldersoundguy
Well-known member
Has a different XLR-XLR cable been used successfully, or is it just the XLR-TS cable that's known to work?
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ecc83
Well-known member
Ha! They seem to be offered here at a nifty +. One firm wants £115 for one and Vendilo Cava list them at £26.08 but want £19.34 p&p! I should bloody co-co! I have sent mics to my son in France, airmail for a lot less than that.
Dave.
Bobbsy
Boring Old Git
Okay, clutching at straws here, but...
All the 60Hz stuff on the signal tells me it almost must be mains related but you say it's still there when you unplug your laptop and use the batteries.
Is there perhaps a fault with the mains wiring in/through the room you're using? A missing ground maybe? Or a heavy duty cable overhead? Or something? Maybe you should go to a park and try it there away from your house (and I'm only half joking!). I mention this because, years ago, we had problems with the tie lines from one of our studio--a long (80+ metre) run but all line level and all balanced. In the end it turned out to be that the lines were about a metre away from a 200 amp 3 phase feeder for our air conditioning plant...and moving things farther away from each other fixed the problem.
All the 60Hz stuff on the signal tells me it almost must be mains related but you say it's still there when you unplug your laptop and use the batteries.
Is there perhaps a fault with the mains wiring in/through the room you're using? A missing ground maybe? Or a heavy duty cable overhead? Or something? Maybe you should go to a park and try it there away from your house (and I'm only half joking!). I mention this because, years ago, we had problems with the tie lines from one of our studio--a long (80+ metre) run but all line level and all balanced. In the end it turned out to be that the lines were about a metre away from a 200 amp 3 phase feeder for our air conditioning plant...and moving things farther away from each other fixed the problem.
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RockDiedin2005
New member
Is there any reason only a balanced cable would pick up any ground issues? As far as I can tell, it can't be a ground loop because it's a one-sided setup: power to PC > USB audio int > TS-XLR Mic ... no mixers or anything else connected to power to create a loop.
I've been pretty much certain the problem was the faulty cheap XLR cable, honestly surprised nobody's backed me up on that yet. I'll have a new, LyxPro cable in a few days to test out.. will post conclusive tests once I can.
I've been pretty much certain the problem was the faulty cheap XLR cable, honestly surprised nobody's backed me up on that yet. I'll have a new, LyxPro cable in a few days to test out.. will post conclusive tests once I can.
Bobbsy
Boring Old Git
It could be a faulty cable...but a cable can't create 60Hz interference all by itself. USUALLY, with a balanced cable it just works or doesn't (or perhaps crackles when you wiggle it). A faulty ground can make a balanced cable susceptible to outside electrical interference...but it bugs me that the 60Hz must be coming from somewhere and, by going to battery, you've pretty much ruled out the computer power supply.
bouldersoundguy
Well-known member
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ecc83
Well-known member
" The first connection is XLR. If the insides of the mic cancel out the balanced signal, what would have been the point?"
Yes Rock' totally agree! No point at all but they DO do it! Not Shure of course but somewhere along the line in a Chinese factory the error was made and so has persisted.
I cannot know for sure of course and it is very frustrating for me to sit here with the means to find out in seconds and you cannot!
And so I shall continue to bang on about musicians and recordists buying the very basic means of circuit testing. You COULD build a house without a line and level I suppose....But wouldn't want to be inside it!
Dave.
Yes Rock' totally agree! No point at all but they DO do it! Not Shure of course but somewhere along the line in a Chinese factory the error was made and so has persisted.
I cannot know for sure of course and it is very frustrating for me to sit here with the means to find out in seconds and you cannot!
And so I shall continue to bang on about musicians and recordists buying the very basic means of circuit testing. You COULD build a house without a line and level I suppose....But wouldn't want to be inside it!
Dave.
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RockDiedin2005
New member
Not yet. By midweek I'll have another to test.
I really have no idea either what could be the source.. There are no wall warts anywhere near the cable, and I even moved the landline phone out of the room just in case that was it.
Haha, sorry bout that, didn't mean to ignore ya earlier.
So Dave, with a multimeter I could also test to see if the mic is internally balanced? Don't be frustrated.. we'll figure it out sooner or later!
bouldersoundguy
Well-known member
I'm not Dave but...
Continuity between pins 1 and 3 on the mic means it's unbalanced.
Balanced signals have a ground, a "hot" and a "cold". Ground is the stable reference point, hot is the signal and cold is the mirror image of the signal. The 1, 2 and 3 pins on an XLR are ground, hot and cold respectively. If pins 1 and 3 are connected then there is no difference between ground and cold, thus it's not balanced.
A meter would not only let you find that out for sure, it would also let you test cables so you can know definitively if they are working or not. On the DCV setting you can test batteries. It's a great thing to have around.
