Audacity Forum

cyrano wrote:

cyrano wrote:Have you ever tried the third possibility in Audacity's input list "sound input"?

That could be the line input, I think. But frankly, I don't remember clearly, as it's a long time ago...

Did you try this?

I switched the input to 'Sound Input' as suggested. It appears to yield EXACTLY the same results as when set to 'External Mic/Line In'.

Mmmm... Thanks.

I seem to remember a sensitivity of 30 mV for these, but with a mono + pip power setting besides the stereo in. I had a 450 MHz version. Let me see if I can find the schematics and work out what Apple concocted exactly...

First up let me once again thank EVERYONE for their 'input' here (pun intended!) OK, sorry to keep banging on about this but, bottom line, I'm still confused this end! You have to remember, I'm a first time Audacity user ('noob'!) and have no experience or point of reference using this software. At this juncture in the proceedings can I clear something up once and for all that is the crux of my confusion here? Here goes:

When one is recording to Audacity from an external line level source (as I am trying to do) within Audacity itself are you supposed to be able to control the levels coming in?? I don't seem to be able to.

I will endeavour to attempt some more sonic tests later on (and will screenshot the results if I stumble across anything new this end) but, I have to admit, I'm getting to the point where I'm jaded with this. It just appears unneccessarily complicated from where I'm standing. We're on to 4 pages here and all I want to do is just be able to convert an analogue sound source to digital whilst controlling the levels coming in (they NEED to be a max. peak of -6dB for sending away to a mastering house and I can't achieve this - my max. peak seems to be closer to '0dB').

In theory at least this should be a 'simple' task, right? Why then does it seem like rocket science to me as things stand? Perhaps I've thrown a spanner in the works here with all my tape portastudio speak but surely it shouldn't matter what source is being recorded in be it: a portastudio? A cassette deck? A radio? A wax cylinder even?!! The fact of the matter is that, using the set up available to me, I just don't seem to have ANY control over the line level my recordings are coming in at (unless I monitor through the 'headphone out' which isn't recommended in the user manual for my unit - it states to use the dedicated stereo RCA 'line out' sockets for best fidelity).

Is this situation (ie: not having any control in Audacity over sound sources when inputted via 'line in') THE NORM then?

Apologies for bangin' on here but you can hopefully understand my confusion (and feel my pain here - LOL!) Thanks again!

7track wrote:When one is recording to Audacity from an external line level source (as I am trying to do) within Audacity itself are you supposed to be able to control the levels coming in??

The recording/playback sliders in Audacity are intended as a convenient way to access the recording/playback controls of the audio device driver.

When Audacity scans for available audio devices (on launch and on "Rescan audio devices"), it looks to see if the sound system makes volume controls available. If record/playback controls are available, then Audacity's record/playback sliders are enabled for that device, if not, then Audacity's sliders are disabled for that device. (On most Linux systems, the recording level is not exposed, so the recording level slider in Audacity is greyed out.)

When enabled for the selected audio device, moving the sliders sends a request to the sound system to change the recording/playback level. The audio device driver "should" adjust the level in response to the request, though some sound systems do this.

When the playback / recording levels are not available, or do not respond to requests by Audacity, then you need to use the audio device driver controls directly. On Mac OS X the device controls are in the Audio/Midi setup settings.

steve wrote:If record/playback controls are available, then Audacity's record/playback sliders are enabled for that device

Yes, they are enabled. The problem I have is that the only control I have over the slider is to make things LOUDER when what I actually want to do is to make my line-in input QUIETER. I am currently recording with the Audacity slider all the way to the left yet the input is still too hot. I've now set the input in Audacity to 'Sound Input' and in the Mac's AUDIO/MIDI SET UP the inputs are at zero so I still don't understand. It feels I have exhausted all options yet I'm no further forward than I was when I started ie: same problem namely: I can't lower the 'line in' input level (which is too hot) - I can only make it louder. I don't understand why the Stereo Output Channel on my Tascam Portastudio mix (which is peaking at the 0dB level recommended in the user manual) is also reading max peaks of 0dB in the digital domain in Audacity. How can this be? If I'm not mistaken 0dB (aka 'Unity Gain') in the analogue world should by rights be reading -18dB on the digital scale surely? (ie: TONS of headroom - I currently can't get any!) "AARRGGH!" I'm having a bad week

I shall re-read ALL of this thread again and then, refreshed with the info, shall endeavour to discover what on earth it is I am doing wrong here! Wish me luck ....

I think the issue is a peculiarity of your old computer. Assuming that the audio input is supposed to handle either a mic or line level (the input has a picture of a microphone), and given that a "line level" signal is very much higher than a typical "mic level" signal, then the recording level when using a mic will need to be fairly high, but when recording a much higher "line level" signal, the recording level will need to be very low.
Try setting the recording level in the "Audio MIDI setup" to zero. My guess is that will set the recording level to "line level", so that 0dB input signal will produce (about) 0dB in Audacity.

Zero dB in tape is goodness...

Zero dB in digital is bad...

With tape you have to record as hot as possible, because you need to get as much distance as possible from the noise floor (-60 to -70 dB typically). And going over zero a bit, just gives a bit of cubic distortion. Most people like cubic distortion, especially on rock music.

In the digital world, 16 bit gives a -96 dB noise floor. Nothing to worry about. But going over zero just a tiny bit will sound awful. So you record at an average of -12 dB, or even lower as you have plenty of dynamic space to work with.

kozikowski wrote:Anybody else notice the posted track seems to be mono? Almost perfectly matching sound meters and identical blue waves?

Yes I pointed that out http://forum.audacityteam.org/viewtopic ... 43#p312143.

Is the result completely mono when you choose the "Sound Input" instead of "External microphone/Line In"?

Does moving the input sliders in Audio MIDI Setup for the recording device chosen in Audacity affect the sound, so that it distorts when you turn the sliders up? Or does it make no difference?



Gale

I 've checked schematics and service docs. Only info:

• two built-in stereo speakers, internal microphone, dual headphone jacks,
analog audio in/out line level jacks
• digital audio, spatializer N-2-2, AC-3 Playback, bass enhancement

Nothing about levels. And line level could mean anything, in AppleSpeak.

You might as well use a simple external attenuator, like this one:

https://www.amazon.com/Volbox-Adjuster- ... B00XDKKQ9E

or this one:

https://www.amazon.com/dp/B00WGPKCLE

cyrano wrote:You might as well use a simple external attenuator

I went out again to do some (more) tests this evening but first to install the new internal battery I'd acquired for the PRAM. New battery installed I rebooted the Mac, set the correct date & time and used the padlock item to lock in the info. I then did a restart and ... NOTHING! It powers up but I don't even get to the Apple start up page. It was working fine before I set & 'locked' todays date. Any ideas, I'm completely stuck!