In the MG10/2 mixer manual it states the following:
To achieve the best overall system S/N ratio, amplify the input to the desired average level as early as possible in the signal path.
In the MG10/2 mixer manual it states the following:
To achieve the best overall system S/N ratio, amplify the input to the desired average level as early as possible in the signal path.
In our mixer, that means the head amplifier. If you don’t get the signal up to the desired level at the head amplifier stage, you will need to apply more gain at later stages, which will only amplify the noise contributed by the preceding stages. Just remember that too much initial gain is bad too, because it will overload our channel circuitry and cause clipping.
I understand what it says, but what should the amplified level objective be to optimally drive the transmitter? What kind of amplifier should I be looking for?
I'd like to revise that question a tad..
What should I use to amplify the line level outputs of my tape decks, cd player and whatever other equipment BEFORE it goes into the mixer, so that the signal to noise ratio will be at it's optimal levels?
Well you do not want to end up over-driving that is for sure. Also you do not want to be increasing the noise floor from those analog sources either.
I would tie those sources into the mixer first without any pre amps. I have never had to add pre amps for line level stuff. Especially on mixers that have an adjustable input or a switch to go from a mic level to a line level input.
No matter what occurs, analog sources will always have a noise floor inherent to them. Even a CD player, when using the analog outputs, will have some noise floor. Also a CD itself can have noise floor if it was mastered from an analog master tape.
"The music on this Compact Disc was originally recorded on analog equipment. Because of its high resolution, the Compact Disc can reveal limitations of the source tape" Always written on the back jewel case cover if the material did come from an analog master.
Another note to add. Do you have a reference tape and CD to work with? A reference tape and CD is a source with set standards for levels in both -10dbu and 0dbu, along with other test signals like white noise, audio frequency sweeps and quieting.
RFB
RF, I wasn't planing on adding any kind of preamp until I read the above statement in the mixer manual.. and it seemed to indicate that one may be required, and wonderd what would normally be used in this case.
As far as a reference tape and CDs, I have no familiarity with them, but I'll look it up.
Line levels can mean different things.
Besides the kind of line, balanced or unbalanced, there are at least several standards:
consumer equipment typically operates at -10dB line level.
Professional gear operates at either 0dB or +4dB line levels, and I've heard of higher levels.
Entirely different solutions are required to mix and match all these variations.
Up until now, we don't know what we're talking about.
I'm not at the house right now, but the mixer manual says to input only a -10db signal in and to make sure its at a sufficient level of volume before entering mixer.
Trust me, at -10 db inputs with line level consumer stuff, your not gonna need any pre amp. If you pump in pro stuff with 0db or +4 or higher out to those -10db in's you will actually need an attenuation pad instead of a pre amp
RFB
That's the ticket. It's just not that complicated.
For your operation, you don't need to amplify anything you input. Period.
Why? Because your mixer has preamps in each channel. These are what control input levels. They also have basic EQ, and Aux sends, which you can deal with each at a time, when you're ready.
In your mixer, just start: plug in your CD player to the stereo inputs and your low Z mic into an XLR mic input, then plug in your headset. Don't connect any other outboard gear yet.
Set the gain controls at the top to UNITY GAIN. With the manual open, play with the mixer controls and listen to what happens. Fade between the mic and the music (turn one up and the other down at the same time). Pan from left to right Play with the EQ in the mic channel. Get a handle on it. Then we'll proceed.
My last post may have been stated incorrectly earlier, what I meant to say is that my manual said to always feed the –10 dB inputs with a –10 dB signal and make sure it was at a sufficient volume before entering the mixer.. I didn't mean to indicate pumping pro stuff into it.
How quick I forget my previous error in having my laptop volume up too high making xmtr sound crappy... It's just that when the manual had made it a point to highlight and emphasize in bold print to "amplify the input to the desired average level as early as possible in the signal path.., it had indicated to me that some kind of amplifier needed to be incorporated.
But it's no longer a question and I understand your points. - only trying to explain where my confusion on this came from.
I think I'm making this all so much more complicated than it is... I got to quit doing that, and just do it!
"I think I'm making this all so much more complicated than it is... I got to quit doing that, and just do it!"
Yep ... it's not bloody likely you will hurt anything,. I mean: There are risks stepping off the curb anywhere, but you still need to get where your going. Follow the road maps in the manual. You'll figure it out.
There are some precautions. Watch the PEAK light, and do your sound check as the manual describes.
RF, I wasn't planing on adding any kind of preamp until I read the above statement in the mixer manual.
Well its good to read the manual..no faults there. But like you were saying, your causing more of the confusion and roadblock than is necessary...no faults there either...some of this stuff can get scary and quite intimidating.
Get one of these...
http://www.mcmelectronics.com/product/80-815
It is an audio test CD. Contains all the test tones and sweeps you need to properly set all your mixer inputs to a base starting point. Just plug in the CD player straight from its output to an input on that mixer, run the 0db test tone and adjust your input gains and channel fader for 0 on the vu and do that for all the channels. Then plug your other stuff in to the mixer and you will be well within the ballpark.
For 5 bucks and a little shipping, its the best darn tool you could ever have for audio work. It can also be used to calibrate your modulation on the TX by doing the same as you would with the input of the mixer. Simply plug that CD player into the TX...run the 0db tone, adjust TX input level...there ya go.
RFB
I was checking out this site: http://www.audiocheck.net/
It appears to provide the same features for free
!
Ya the only problem with using those is that you have to make sure that the levels coming out of your computer are accurate, or that the download files offered, if any, are also accurate.....most of them are not.
I would not rely on those online audio testing sites, at least not for true accurate level settings. For general purposes just to see if your getting a signal going to and from....be just fine.
RFB
2FWIW, here's part of my current setup:
http://www.pixelbird.clearwire.net/images.html
In the board, the orange faders on the right are my subgroups two mono signals per channel. Can't see the back, but there are 4 XLRF recording snake connectors which end in TRS connectors. In the interface in the second pic, you can see I split up the TRS ends into 4 sets of mono pairs, 8 channels in all.
Now, I can assign e.g. a stereo signal to, say ch's 1 (L) & 2 (R) in the software. Be that as it may, the thing to know is that the very short splitters are unbalanced while the TRS snake ends are balanced. Further, the interface has its own (quite good) preamps.
However, I'm not connecting preamp to preamp, but rather a controlled recorder output from the board to the interface's preamps.
So, why use a 24 channel board? you ask. I have a DJ statioin on the sound stage in the other room, or I can set up for a band. Still, for thew most part, I could use the interface directly, but I have CTS, and the faders in that ol' Tascam board still glide like angels ... no comparison to most compact desks, and certainly not manipulating the screen with a mouse, or even specialty controllers.
However, I do all the effects and limiting with software. I'll post a video later, where you can hear the sound.
Hey! Actually, why don't we do an online video chat .. our own Part 15 live online tuts? Hmmm.