Audacity Forum

I have just purchased a USB turntable (Ion Contour LP - no output control) for recording my LPs via Audacity using Windows XP. The recording works although I have to have the volume slider in the audio tab of the XP control panel right at the bottom limit to avoid clipping. However, there are some fundamental things I don't understand
(a) during recording the input & output level meters read identically - it's not clear whet they mean
(b) the Audacity mixer input volume control has no effect on the level shown by the input level meter & all it does is scale the displayed audio signal i.e. if the input level meter indicates clipping then moving the slider on the input mixer down doesn't remove the clipping - it just occurs on the audio signal at a lower position. So what good is the input mixer control?

Overall, it seeme that the only control I have over the audio input to the system from the turntable is via the volume control on the audio tab of the XP control panel & this is already at one of its limits. This seems unsatisfactory & strange.

Am I misunderstanding something fundamental; is something wrong or what? I don't find the help documentation very useful and I need some advice please.

Thimbles

thimbles wrote:Overall, it seeme that the only control I have over the audio input to the system from the turntable is via the volume control on the audio tab of the XP control panel & this is already at one of its limits. This seems unsatisfactory & strange.

No - that's what you expect with a USB device - Audacity hands control over to the device

thimbles wrote: (a) during recording the input & output level meters read identically - it's not clear whet they mean
(b) the Audacity mixer input volume control has no effect on the level shown by the input level meter & all it does is scale the displayed audio signal i.e. if the input level meter indicates clipping then moving the slider on the input mixer down doesn't remove the clipping - it just occurs on the audio signal at a lower position. So what good is the input mixer control?

a) if you haven't adjusted the output volume with its slider - then you would expect bith to be the same. They are the signal levels for input and output.
b) as I implied above with a USB device like this the input slider will have no effect as Audacity hands control over the signal to the USB device.

Have a read of this article in the Wiki: http://wiki.audacityteam.org/wiki/USB_turntables

And this set of tutorials from the manual under development for 1.3/2.0 should help you too: http://manual.audacityteam.org/index.ph ... iscs_to_CD

WC

Hi WaxCylinder & thanks for your reply.

Neither the input or output sliders on Audacity have any effect on either the input & output level meters during recording. During playback of a recorded track, the output slider adjusts the volume of the sound but has no effect on the output level meter. Why is this & what exactly do the level meters represent?

I am interested to learn that that Audacity cannot control a USB device. Since the device has no volume control, does this mean that the only control over the recording level and the avoidance of saturation is via the XP control panel?

If I set up the system (i.e. the control panel volume) for a single LP, can I rely on this setting to work optimally for all LPs. In other words, were LPs made so that the maxiumum ouput level was a fixed value which presumably would be around -3db on the input level meter in order maximise the gain and resolution without running into clipping?

Thimbles

thimbles wrote: Neither the input or output sliders on Audacity have any effect on either the input & output level meters during recording. During playback of a recorded track, the output slider adjusts the volume of the sound but has no effect on the output level meter. Why is this & what exactly do the level meters represent?

See this page from the manual under development for 1.3/2.0: http://manual.audacityteam.org/index.ph ... er_Toolbar

thimbles wrote:I am interested to learn that that Audacity cannot control a USB device. Since the device has no volume control, does this mean that the only control over the recording level and the avoidance of saturation is via the XP control panel?

Yup – and not all Widows implementations seem to let you do this (judging from other posts on the forum) so you are lucky. I’m puzzled about your ION though – I used to have an ION iTTUSB and it did have a gain/volume control – it wasn’t in a convenient or obvious place though – it was underneath at the back, a little knurled knob,

thimbles wrote:If I set up the system (i.e. the control panel volume) for a single LP, can I rely on this setting to work optimally for all LPs. In other words, were LPs made so that the maxiumum ouput level was a fixed value which presumably would be around -3db on the input level meter in order maximise the gain and resolution without running into clipping?

You might well think that – and there is some intention to do something like that – but it doesn’t seem to work out in practice. Provided you get a good recorded signal you can always use the Amplify or Normalize effects to bring the volume up after recording. It’s not like analog tape recording where you want the best & strangest available signal right aff when you record.

WC

If, during recording, both the red recording and green playback meters operate, then you have Hardware or Software playthrough selected in Audacity preferences. Not everybody supports Hardware Playthrough but it's the best for delay and other problems.

Software playthrough works everywhere, but it's always behind the performance sometimes by significant fractions of seconds.

Koz

Thanks waxcylinder

There is no volume control on the ION. At least I can't find one & the instructoion book doesn't mention one. I bought it at Maplins & it may be a cheap special for them.

So far I've checked 4 or 5 LPs and amazingly the maximum level seems to be around -3db max. However, since my sound card volume control is down to the minimum I would seem to be somewhat screwed if one of the 200 LPs I want to record has a bigger output level leading to clipping.

I don't really understand your comment about the recording level not mattering too much as it can be adjusted later in effects. I've had considerable experience with ADCs and data acquisition and if you reduce the level into an ADC too much then you lose bit resolution that cannot be fully recovered by amplifying the digitised signal. However, I want to burn the tracks to CDs (16 bits) & presumably I can record using 32 bit format allowing me a lot of slack in the recording level. I think my sound card (SB Audigy 2) has 24 bit resolution but I would need to check that.

Thimbles

thimbles wrote:I don't really understand your comment about the recording level not mattering too much as it can be adjusted later in effects. I've had considerable experience with ADCs and data acquisition and if you reduce the level into an ADC too much then you lose bit resolution that cannot be fully recovered by amplifying the digitised signal. However, I want to burn the tracks to CDs (16 bits) & presumably I can record using 32 bit format allowing me a lot of slack in the recording level. I think my sound card (SB Audigy 2) has 24 bit resolution but I would need to check that.

I infer from you comments there that you probably do understand what I was getting at

Yes working in 32-bit float in Audacity will give you plenty of headroom for applying effects like Amplification or Normalize - you just need a good signal a good level - I have my meters set to dB rather than linear - I ty to max my recordings at about -6dB or so - and as my final production step I amplify up to -1dB. I work in 44.1kHz 32-bit and then export to 44.1 kHz 16-bit WAV for making CDs and importing into iTunes.

BTW note that you can enlarge the meter tool bar (makes it a lot more useful) by clicking and dragging on it - in 1.2 it floats and is resized gor that sessuion only - but in 1.3 you can re-size it and reposdition it, so it stays that way next time you launch Audacity.

Also note that your Audigy soundcard will not be used for recording while the ION USB TT is connected - as then it will be using the soundcard, ADC, that is onboard in the ION TT.

WC

thimbles wrote:So far I've checked 4 or 5 LPs and amazingly the maximum level seems to be around -3db max. However, since my sound card volume control is down to the minimum I would seem to be somewhat screwed if one of the 200 LPs I want to record has a bigger output level leading to clipping.

I've just had a chat with the ION Tech Support team in the UK - they confirm that there is indeed no gain control on the ION Contour.

The -3dB max is fine - but yes you would be stuffed if any of your LPs delivered a signal that led to clipping.

ION's suggestion for a workaround would be to use the EZ-vinyl software that they also provide to record such an LP as that has a s/w gain control. You can then load the output file into Audacity for further processing.

ION do seem to get the settings right though (unlike some other USB TT manufacturers) - with the ION iTTUSB that I used to use I did not have to move the gain control from its max setting for any LP - I hape two problem cassette tapse (fed in through the ION) which require a slight gain adjustment to avoid the signal clipping.

WC