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 most Ion turntables, the Behringer 202 and the NAD-PP4) have no recording level control that can be adjusted via VinylStudio's recording level slider.  This means that if the signal is be clipped (i.e. exceeds the maximum level that your PC can handle) on loud passages of music there is nothing VinylStudio can do about it.  This is because the signal is clipped before it even enters the PC.

Some devices, such as the NAD PP-4, offer a gain control on the front on the unit and this is a simple and effective solution.  Others (most, in fact) do not, which can be awkward.

At the software level, VinylStudio deals with this in one of two ways:

• If you check the 'Use WASAPI when recording' box in the Check Level dialog, then the slider is disabled and whatever it then happens to display is irrelevant - VinylStudio just uses a straight-through signal path.
• If you uncheck that box, then VinylStudio displays a 'Set Digital Gain to 1' button and you should click it.  Any other setting of the slider is sub-optimal.

It is tempting to reduce the slider setting if VinylStudio tells you that the signal is clipping, but all that does is mask the problem. If clipping is occurring, the flat tops of the waveforms will still be there and if they are severe enough, audible distortion will result.  All that turning the slider down achieves is to hide them from the clipping indicator.

Some USB devices (including the PP-4) also incorporate traditional (analog) line-out sockets.  If so, you can run a cable like the one pictured here to line-in on the soundcard built into your PC or (older) Macs.  If the clipping is severe this is often the best solution.

If, on the other hand, your recording is too quiet, you can boost the playback level after recording by normalising the recording as shown on our videos page.  Boosting the input signal with the recording level slider (i.e. by moving it above the 'Set Digital Gain to 1' setting) is then also a viable solution, but please be careful. Never, ever, set the slider below that level if that button is on show, for reasons already given.

Please note that XP users are unaffected by any of this.  There is still no slider, nor is there any need for one as XP does not meddle with the input signal in any way.  And it works the same way on the Mac.

Note: Some of the posts below refer to older versions of this post, which has now been substantially revised.  Most of them therefore probably don't make much sense anymore.

[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.

[hesson11]

Paul,

There's something implied here that I want to make sure I understand (apologies for being the slow one in the class):

Using ANY USB input device (i.e., an audio interface or a phono-preamp-interface like the Parasound Z-Phono USB, etc.) will defeat the recording-level controls of VinylStudio? And in order to adjust the level, the USB device must offer the ability to make that adjustment? Do I have that right? THANK YOU!
-Bob

[Paul Sanders (AlpineSoft)]

More or less.  It's actually any USB device using the Texas Instruments / Burr Brown 2902 / 2904 / 2906 USB controller chip.  Most budget and mid-range USB audio devices use this chip, hence the need (ideally) for a gain control on the device itself.  In the case of the NAD PP-3, NAD have calibrated it for the most popular cartridges and implemented a soft-clipping algorithm.  Not perfect perhaps but it seems to work in practise.

The problem is rooted in the hardware.  These chips offer no software-adjustable control of the recording level.  It's simply not possible, they left it out of the design, I have no idea why.

[hesson11]

Thanks, Paul.

In case anyone else may be considering using the HRT LineStreamer+ as an A/D converter, I've contacted the company to see what kind of USB controller it uses, and the reply was:

"The LineStreamer + utilizes a custom USB interface based upon the TAS1020B front end."

Sounds like it does not use the chips you mentioned. I'm guessing this means the LineStreamer+ will probably not defeat VinylStudio's gain control. Perhaps this information will be useful to others. THANKS!
-Bob

[Paul Sanders (AlpineSoft)]

OK, thank you.  Are you planning to purchase one of these?  If so, perhaps you could report back.