Where has my Recording Level Slider Gone?

[Paul Sanders (AlpineSoft)]

We get a lot of questions about this. The fact is that many USB devices (including the Ion turntable, the NAD PP-3 and the ADS Instant Music) have no recording level control.  This means that if the signal is clipped (i.e. exceeds the maximum level that your PC can handle) on loud passages there is nothing VinylStudio can do about it.  This is because the signal is clipped before it even enters the PC.

The NAD PP-3 implements something called soft-clipping.  This deals with the problem very effectively, preventing any audible distortion in the majority of cases.  NAD have also gone to some lengths to match the input sensitivity of the PP-3 to most cartridges, provided that you set the MM/MC switch correctly on the back of the unit (and use the corresponding input sockets).

The Ion turntable offers a mechanical level on the back of the unit and you should use it (although some people have reported that it doesn't always work and that it is missing on some models).  The ADS has no level control at all.

Some software - including the Windows Sound applet - still offers a recording level slider for USB devices like these but all it does is mask the problem. If clipping is occurring, the flat tops of the waveforms are still there, even if the signal is attenuated inside the PC, and if they are severe enough audible distortion will result.  To put it another way, these level controls are just misleading and we therefore set the level to the maximum value regardless; setting it lower just sacrifices dynamic range and is therefore counter-productive.

Many USB devices also incorporate traditional (analog) line-out sockets.  If so, you can run a cable like the one pictured here (http://www.alpinesoft.co.uk/VinylStudio/connecting_up.aspx) to line-in on the soundcard built into your PC.  If the clipping is severe this is often the best solution.

If your recording is too quiet, you can boost the playback level using the preamp slider in VinylStudio's graphic equaliser before burning CDs or saving your tracks as MP3 files.

Update, 16Jul09: thanks to the post below by jonk, we have now discovered that there is a twist in the tail.  Vista SP1 and later (and Windows 7) actually scale up the input signal if the recording level slider is set to maximum.  This makes it impossible to determine whether clipping is occuring inside the USB device (which it sometimes does) or as a resut of this unwelcome intervention by Windows.  In any event, it means that VinylStudio needs to allow the slider to be adjusted on these operating systems and we have therefore reinstated it as of V6.20.

I think this explains why some users were reporting such severe problems.  We would like to apologise to anyone who has been inconvenienced by this misunderstanding on our part - we were fooled by testing on the original version of Vista - and advise all users with USB devices to upgrade to the latest version of VinylStudio.

Please note that XP users are unaffected.  There is still no slider, nor is there any need for one as XP does not meddle with the input signal in this way.  And it remains true that most USB devices have no hardware level control.  We did some additional tests to make sure.

[Paul Sanders (AlpineSoft)]

Question: You say there is no point providing a recording level control in software for USB devices.  Why?

The reason why this doesn't work (or it least, doesn't do anything useful) is that the signal is digitised before it enters the PC.  The digitised signal is limited to 16 bits per sample and if it exceeds that level it will be clipped inside the USB device.  After it reaches the PC, all that can be done is to scale the numbers down.

To put it another way. each sample is just a number and if it exceeds 16 bits (-32767 ..  32767), the excess cannot be transmitted across the USB bus.  The glass is full.  Period.

[Muddler]

Could you please clarify something regarding the NAD PP-3 - you say that the device implements "soft-clipping".  When recording from the device, the software registers literally a thousand or more clips each song.  My cartridge outputs 5,5 mV.  If your software is registering clips, there are indeed clips, correct?  In other words, this "soft-clipping" isn't stopping clipping when your software registers clips, right? 

Fortunately, I have an alternate recording option, so if the answer is that I'm going to lose audio quality using the PP-3 as a USB out device, better to know now before I do a lot of recording only to play audio back later and wonder why it sounds off.   

Thanks.

[Paul Sanders (AlpineSoft)]

Actually, I can't.  I will talk to NAD about this and post back to this thread, but I think the idea is that the waveform is rounded off somewhat, rather than being just sliced off like the top of an egg.  I believe the processing is analogue (a bit like a valve amplifier, which has some soft-clipping characterics) rather than digital, but I could be wrong about that.

As for using an alternate recording option, I would record the loudest thing you can find using both alternatives and have a listen on headphones.  Also record something quiet (or even silence) and listen to that.  Hiss and hum pickup can be a problem with vinyl recordings and the PP-3 has a particularly low noise floor.

[dmerrick]

I Use the ART USB Phono Plus II.

With Version 6 my input is clipping 100% all the time.
My preamp has built-in clip indicators, they work as they should.
But something is different.

This has made the software unusable for me.
Is there a link to DL Ver 5 from somewhere?

Without that gain control, I can't record.

[Paul Sanders (AlpineSoft)]

Hi Dave,

The slider in VinylStudio 5 did nothing useful.  It merely hid the fact that the signal was being clipped before it entered the PC.  I promise you I'm not pulling the wool opver your eyes here; that's the plain and simple truth.

Unless I am missing something, the thing to do is to turn down the gain control on the ART until VinylStudio stops reporting that the signal is being clipped.  You can do this in the Check Level dialog before you start recording for real.  I don't understand why the ART does not report clipping when VinylStudio does.  A shortcoming of the unit itself possibly.

Technical info: ART's own website (http://www.artproaudio.com/products.asp?type=90&cat=13&id=128) states that the unit uses a 'standard A/D interface package'.  This is probably the Texas Instruments 2904 USB chip, which (for reasons I cannot fathom) has no gain control.  You can confirm this by opening the Windows Sound Applet via VinylStudio's 'Recording Controls' button.  It wil most likely report the device as Microphone on USB Audio CODEC, which is the driver Windows uses to talk to the 2904.


----- Original Message -----
From: D Merrick
To: AlpineSoft
Sent: Saturday, March 28, 2009 3:04 AM
Subject: Gain Control gone (via webform)

Hi I know you've covered this in the forums, but I *NEED* the gain control with my ART Phono Plus V2 preamp.

The ART has a built in gain control on the box, and my clip indicators are normal.  However, now in VS6, even though the gain on the art itself shows nominal, I'm 100% clipping (Even on quiet passages) within vinyl studio.

With ver 5, I would turn down the slider and life was good.

Apparently, this preamp is actually chained preamps and the 2nd stage is wide open! (Not good)

IN VS-5, that slider worked.
Now the program is pretty useless.

Like a dummy, I didn't keep a version 5 installer, do you have somewhere I can download version 5?  Right now, I'm out of business.

-Dave Merrick

[jonk]

Hi Paul
I believe the clipping problem is due to a bug in VinylStudio running under Vista. Like Keter (post of 1st Feb), I found that the signal from my standard cartridge (4 mV output) into my Vista-based Sony  laptop (via NAD PP-3 and USB) was saturating. Also like him, I found I could solve this by adjusting the “microphone” volume slider to about 35% after pressing Record in VinylStudio. The recordings sounded fine. I have three reasons for thinking that the clipping is due to software (probably VinylStudio), not hardware:
1. The PP-3 should work fine with a standard cartridge, without clipping.
2. If I use exactly the same record, track, turntable, PP-3, USB cable and VinylStudio 6.1 with my other computer (a new PC running XP Pro), there is no clipping: with the “microphone” slider set to the default of 100%, the signal is only about half of that needed for saturation. So, the hardware is OK. Unfortunately for me, this computer is usually in another room, away from the turntable!
3. To test this further, I recorded the same track on my Vista laptop with the microphone slider set to 100% (top panel in the attached file) or 35% (bottom panel). First, you can see that the slider has made a difference to the recorded signal amplitude, so Keter was right. Second, the fact that clipping occurs with the slider at 100% but not at 35% shows that the clipping is not occurring in the PP-3 but happens after the slider control, i.e. either in Vista or VinylStudio. My guess would be that VinylStudio is not talking correctly to the USB drivers with Vista (though it does do this OK in XP).
I think a bug-fix is necessary (the work-around using the microphone slider is pretty tedious!)
Thanks,
Jon

[Paul Sanders (AlpineSoft)]

You know what? You could be right.  I will investigate as a matter of urgency and post my results back here.

I know for sure that there is no hardware control of the recording level - I have checked the specifications of the USB audio chip that the PP-3 uses - but it may be that Vista is boosting the recording level (in software) when the slider is set at maximum.  If so, we do have a bug and we will fix it straight away.

Thanks very much for taking the time to post.

[jonk]

Thanks. I hope you find something!

[Paul Sanders (AlpineSoft)]

We did (find something).  Microsoft changed the way things work on Vista SP1 and later.  See 'Update' at the top of this thread for more details.  I have to say I can see absolutely no point in them doing what they did.  Nobody benefits by it.

Anyway, I owe you a thousand thanks for the work you put in on this.  Without your help, things would have just rumbled on as before and users would continue to be adversely affected.  As for me, it's 50% humble pie and 50% irritation that MS make changes like this with no warning.  And a slap on the wrist for making assumptions and not testing the software properly.

Once again, apologies to all users affected by this issue, and sorry to have offered faulty advice.  We will release a software update today or tomorrow which will reinstate the slider.

[jonk]

Great news! Glad to be of help. Thanks for your prompt action.