Noisy VST DXi outputs in sonar 4

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mike909
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Joined: Sat Feb 19, 2005 4:00 pm

Post by mike909 »

Hi, have been having a problem with sonar 4/luna ii - vst/dxi outputs routed to the mixer via a wave source have a audible hiss (not very loud, but annoying). A normal audio track however is completly noise free. The problem has only appeared since i updated Sonar to V4.04.

There is also the same amount of noise of the luna analog in - looks like about -83db for both. Is this normal?

Thanks for any help.
mike909
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Post by mike909 »

Scratch that, the problem solved itself the second i posted. Still curious about the noisy input, could it be interference from something in my pc?
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garyb
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Post by garyb »

yes.
ground issue? undersized power supply?
mike909
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Post by mike909 »

my psu is 350w - my system is athlon xp3000, 512MB RAM, 2x120GB 7200rpm hdd, wireless card, ati radeon 5600, Luna II, CDRW and a DVDROM drive. Does 350w sound like enough? I'm about to add a pulsar ii as soon as i get my hands on an S-TDM cable, am i gonna need a better psu?

Whats the best way to resolve a grounding problem?

Cheers.
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astroman
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Post by astroman »

you could make a fortune if you're able to answer that question... :grin:

but some basic knowledge about electronic gear paired with systematic(!) examination and patience will usually work
an open mind (never say never) and some intuition will make you almost a pro - it looks like black magic, but eventually it all breaks down to quite regular explanations :wink:

regarding specs of PSUs it's unfortunately nothing but marketing.
The numbers are almost meaningless so people tend use high Watt ratings just to be on the safe side.

you cannot build a quality PSU for 35 bucks - not even in China. Period.
The thing should be heavy and quiet - invest in the $100 range and you're probably safe.
Even better if the shop allows an exchange after a day testing (f.e. noise of heat regulation).
I've good experiences with a brand named 'Be quiet!' (they live up to their name) but that's by no way exclusive.

cheers, Tom
mike909
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Post by mike909 »

my psu cost me about £80, think it's an ok one. Just got my pulsar ii installed (its sweet having more than 3 dsp), the same problem on the pulsar ii inputs.

I've got a multi meter, is there any point measuring the resistance between the audio earth and the mains earth? Or is the card isolated from the mains in some way?

dont want to spend money getting a digital card for my trakmaster if i dont have to...
djmicron
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Post by djmicron »

i don't know if it's the right solution for your problem,
but i've solved it by removing the ground connection from the ac cables.

Hope this could help :smile:

Micron

<font size=-1>[ This Message was edited by: djmicron on 2005-10-24 15:57 ]</font>
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astroman
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Post by astroman »

... it could as well kill - you and/or your gear :razz:

the behaviour will be completely unpredictable if you do this with gear that is supposed to have a ground connection.
What happens depends on your electrical installation and the tolerance of any unit in the chain.
If a small difference in voltage occurs, an extremely HIGH current will flow (see Ohm's law) and fry whatever is in the way, seriously.

I dunno the values from the Luna or Pulsar 2 as I have the Pulsar 1, but a noise floor of -83 db on empty analog ins is regular (at least with my gear).
Nevertheless I DO HAVE a (reproducable about 3dB) better signal to noise ratio on Pentium III (BX or 815 boards) than on PIV (Intel 865) - strange...

and in fact a software installation can be responsible for 'zippy noises' when moving graphic objects. I've once cured such a system by reinstalling the OS...

did you check if the computer case itself is properly grounded ? Sometimes color prevents this.
As mentioned, patience and a systematic approach applies... you're not the only one wasting one or the other hour in this domain :wink:

cheers, Tom
mike909
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Post by mike909 »

funnily enough i used to get zippy noises until i installed my pulsar. If -85db is about the norm i'll just put up with it, probably won't even notice it truthfully.

Didn't used to get any noise with my delta 66. Maybe its mixer software was too gash to display it.

Thanks for the help guys.
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astroman
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Post by astroman »

as with PSU power ratings, numbers are marketing's darling when it comes to audio specs :wink:
it's so much easier to measure some nonsense than to produce audible(!) quality.

Not even a high end 5-figure super-exotic vinyl player will ever yield a better signal to noise ratio than 70dB. It cannot, due to surface noise of the stylus - but you'd probably be blown away when you listen to record on such gear... :grin:

people tend to project great specs in one domain to another, but it takes more than a flawless frequency response or SNR to produce a nice sound.

the zippy noises are annoying, tho.
With ground problems they are very prominent, but I'm not even sure if a perfectly grounded system would eliminate them completely.
They seem to be related to software interrupts in one or the other way, so it's up to you how much you want to tweak your system (for some unhearable components)...

cheers, Tom
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