[LAD] Half-OT: Fader mapping - was - Ardour MIDI tracer

Grekim Jennings grekimj at acousticrefuge.com
Sat Aug 23 11:56:10 UTC 2014

> Partly also for historical reasons, I think. In many ways digital 
> recording started as the "poor man's tape". Direct to disk recording with 
> no effects was at first all that could be handled and most peole using it 
> were replacing 8 track tape with it. They already had a mixer. As the DAW 
> developed, mix down on the computer has been next. But for many people the 
> recording part of the strip has been outside of the DAW, on an analog 
> mixer. This is changing as a new batch of people are going mic-> 
> interface. Their input strip is whatever the interface provides... often 
> only trim (either as a pot on the pre or in ALSA). 

Is this for convenience or not having the ability to afford something else?
I think a lot of times money is spent on the wrong thing such as buying a 
fancy multicore computer when something from 8 years ago is totally adequate 
for digital audio. 

> So digital recording is 
> also going through a two mixer to inline transition. From hybrid to 
> digital only. The trim controls are there, where they should be, as close 
> to incoming signal as possible. I don't suppose it would be too hard to 
> add alsa trim for a card like the d1010 to ardour, but many USB IFs (even 
> PCIe) have no controls in alsa. It is a physical pot somewhere. So rather 
> than being in front of the engineer, it is hidden and easily missed by the 
> newby... or even not so new. So much is done digitally, that the remaining 
> analog items are forgotten. This is a real problem with a two input IF, 
> The trim needs to be set every time and the variety of signals through one 
> channel is huge. Everything from a ribbon to line level. Having a set of 
> good pre amps could be worth while, this is probably the biggest hole in 
> the hobby studio. I have two, tube and solid state. (plus line)

It is very simple to keep a few notes on what is a good preamp setting for
a given mic and preamp combination.  One inconvenience with some budget
preamps is that you don't know what sort of gain it is providing, so while you 
may write down the setting by using a notation like 2:00 for dial position, 
you haven't learned anything about gain, so if you swap out a preamp you need 
to guess at where to start.
You can get into trouble with a mismatch between preamp and converters, such that
you are trying to "maximize bits" by getting a hot signal level into your converters.
The preamp ends up distorting and you have a hi-res recording of a distorted sound!
I actually had this problem with a remake of a vintage preamp.  So it seems every 
preamp has a voltage sweet spot that it should be operated in.  
The best situation is if you have converters with analog trims, which is I think 
what you were saying, and set them accordingly for each preamp.  I leave my preamps
plugged into a specific A/D channels that have been calibrated for that preamp.  
One other note, some budget preamps are not qualified for certain levels of input.
I have a Presonus Audiobox which can sound fine for an acoustic guitar, but throw a
drum at it and it is automatically over full scale and unusable.  

More information about the Linux-audio-dev mailing list