Noise Floor

[mfny]

Hi all,

Not sure if this is the right forum for this but it was suggested I look here.

I recently bought an Union Audio Elara 4 MK2 DJ mixer and am finding the noise floor is apparently quite a bit higher then the only other Analog DJ Mixer(Allen and Heath Xone 92 MK2) I have owned despite it being higher end/higher cost.

So I have a question regarding noise floor, specifically about the trade offs in a lower noise floor vs other audio quality factors as the manufacture when questioned about the noise floor suggested they had to make a choice between a lower noise floor and other audio quality factors but did not specify what these were.

I am just wondering am I being fobbed off here or is there a real choice here when choosing/specing parts etc as to what to prioritize a lower noise floor or other factors for audio quality ?

 

[AnalogSteph]

In the specs for this model we find:

Noise 22Hz to 22kHz Un-Weighted​

Residual Mix Output noise	<-98dBu
Line In to Mix Out Unity	<-81dBu
Maximum Output Level Mix Out	0.5% THD +27dBu
Dynamic Range	108dB

That would suggest a rather traditional construction - inverting opamps galore, high levels, high impedance. You may be paying mostly for the build quality from what appears to be a boutique UK company (it goes without saying that those cranking 'em out in volume in the Far East are going to have economics of scale on their side). That being said, it's not like your previous mixer had any better specs.

Possibly you are inadvertantly running afoul of gain staging. With up to 3 level trims in the signal path, this could definitely happen, although your channel meters and master output meters should generally give you a good idea how healthy your internal signal levels are. Note that according to the block diagram, the master output meters are just ahead of the master fader, unlike some Behringer and Mackie mixers I've had that had them on the output and sported an input clipping LED at best. Being used to the latter may lead to mishandling of levels.

Which kind of output with what kind of associated external equipment is giving you trouble with noise? Or is it the input side; if so, any sources or just a specific one? As the line-ins are unbalanced, the usual disclaimers regarding ground loops apply (the manual's Application Guide is only showing floating sources for good reason), plus with the mixer using a small switch-mode power supply a ground loop may well manifest itself as excessive noise.

 

[DVDdoug]

specifically about the trade offs in a lower noise floor vs other audio quality factors as the manufacture when questioned about the noise floor suggested

Not really. Ideally it should be better than human hearing in all aspects.

But noise is tricky. Audibility will depend on gain (noise gets amplified too), including the gain of your power amp, the sensitivity of your speakers (or headphones), how close you are to the speakers and other acoustic noise in the room.

If you are getting AC hum it's probably a ground loop problem which might not be the fault of the equipment. Hiss usually comes from the active electronics and whine usually comes from a switching power supply (switching noise getting into the analog electronics).

DJ mixer

Phono preamps and mic preamps are high-gain so noise is more of an issue than with digital sources and line-level signals.

 

[mfny]

In the specs for this model we find:

Noise 22Hz to 22kHz Un-Weighted​

Residual Mix Output noise	<-98dBu
Line In to Mix Out Unity	<-81dBu
Maximum Output Level Mix Out	0.5% THD +27dBu
Dynamic Range	108dB

That would suggest a rather traditional construction - inverting opamps galore, high levels, high impedance. You may be paying mostly for the build quality from what appears to be a boutique UK company (it goes without saying that those cranking 'em out in volume in the Far East are going to have economics of scale on their side). That being said, it's not like your previous mixer had any better specs.

Possibly you are inadvertantly running afoul of gain staging. With up to 3 level trims in the signal path, this could definitely happen, although your channel meters and master output meters should generally give you a good idea how healthy your internal signal levels are. Note that according to the block diagram, the master output meters are just ahead of the master fader, unlike some Behringer and Mackie mixers I've had that had them on the output and sported an input clipping LED at best. Being used to the latter may lead to mishandling of levels.

Which kind of output with what kind of associated external equipment is giving you trouble with noise? Or is it the input side; if so, any sources or just a specific one? As the line-ins are unbalanced, the usual disclaimers regarding ground loops apply (the manual's Application Guide is only showing floating sources for good reason), plus with the mixer using a small switch-mode power supply a ground loop may well manifest itself as excessive noise.

Im not so much bothered by the hiss at high volumes that I presume is the noise floor that I am bothered by the apparent noise(which on my speakers sounds like a rustling noise like a microphone is being brushed against) made when I sweep the volume control from one position to another on the Master and Booth outs which I don't recall the 92MK2 doing at all and it has been suggested by one person that this may be oxidization on the pots. I have recordings of this that I will attach recorded from my SSL2+ interface with gain set to 3 o'clock and levels on the meters of the interface not going red. These 2 files are me sweeping the volume control from min to max slow and faster. Note that the noise does not sound the same directly recorded then on my speakers so im not sure how good a test this is.

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jumpshare.com

404 File Not Found - Jumpshare

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jumpshare.com

Edit: Not sure why the above is 404 file not found, if you click on the links it should work