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Sorry to ask - clicks n pops on pandemic-imposed laptop

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Sorry to ask - clicks n pops on pandemic-imposed laptop

Postby Darren Lynch » Wed Aug 05, 2020 8:49 am

Dear All,

First off, I hope you are all bearing keep up and keeping well.

To work from home during the current situation I bought a Windows laptop:

HP Pavilion 15-cs3001na Laptop, Intel Core i5 Processor, 8GB RAM, 512GB SSD, 15.6" Full HD

I tacked on a requirement for a dedicated graphics card (a lower powered nvidia job) in the hope of creating a portable recording solution to run alongside my very reliable iMac/Logic combo.

I installed MuLab 8 after it outperformed most other DAWs in the 'operate entirely on first principles' stakes. Then installed EZ Drummer 2. Interface is a Scarlett 2i2 3rd gen

I made all the Win10 optimisations proposed by the Focusrite website.

But just playing EZ Drummer with a responsive buffer of 64 or 128 produces audible clicks (CPU meter in MuLab shows 10% use at most). Nothing has been recorded to the SSD.

Is there anything I might have done wrong? (PS: I don't "do" the PC v Mac debate. Both platforms have served me very well to date)
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Re: Sorry to ask - clicks n pops on pandemic-imposed laptop

Postby blinddrew » Wed Aug 05, 2020 9:06 am

What's your input device to trigger the drummer? And what else have you got plugged in?
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Re: Sorry to ask - clicks n pops on pandemic-imposed laptop

Postby Darren Lynch » Wed Aug 05, 2020 9:27 am

Midi input is an Oxygen 49 keyboard going into one of the USB ports.
A standard USB mouse uses the other port.
The laptop also has a single USB C port. I have connected the Scarlett to that and it works (Although SOS review makes the point that the 3rd gen Scarletts are in fact USB 2, even though they offer USB C connectivity).
I noticed the clicks when I first loaded up MuLab and played internal instruments using its own virtual keyboard.
Is this just what the 64-bit new normal looks like?
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Re: Sorry to ask - clicks n pops on pandemic-imposed laptop

Postby shufflebeat » Wed Aug 05, 2020 10:19 am

When I went to 64bit in Reaper my little stone age laptop struggled til I replaced all the 32bit plugins, apparently avoiding the necessity for 64bit to get the 32bit manual out and translate.

Apart from that, smoother than before.
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Re: Sorry to ask - clicks n pops on pandemic-imposed laptop

Postby merlyn » Wed Aug 05, 2020 11:36 am

I don't use Windows myself, but I recently helped a friend with his Surface Pro plus 3rd generation Scarlett Solo setup.

One issue was the power management scheme and that is covered in the Focusrite guide.

The other issue was DPC latency and there's a guide to that from Sweetwater here :

https://www.sweetwater.com/sweetcare/ar ... cy-issues/

It could be another driver causing the problem, e.g. the wi-fi.
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Re: Sorry to ask - clicks n pops on pandemic-imposed laptop

Postby blinddrew » Wed Aug 05, 2020 11:50 am

First thing is to update the drivers if you haven't already. Have you got monitors or are you listening over headphones? Sometimes you can get pops and clicks coming in if you've got a floating ground.
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Re: Sorry to ask - clicks n pops on pandemic-imposed laptop

Postby CS70 » Wed Aug 05, 2020 12:10 pm

A Windows laptop can be a tricky proposition to be used as (quasi) real time machine.. that's nothing to do with the OS, but the fact that the manufacturers can put whatever components they want into the machine and Windows still manages to run them well for 99% of the tasks - which do not need realtime properties. That's not a problem with a desktop where you can select - or replace - bottleneck components, but with a laptop, it is.

An additional issue with laptops is that they always come pre-setup to conserve as much energy as possible, exactly the opposite of what you need for real time performance, where everything needs to be on all of the time. The Focusrite guide should have taken care of that however; the most important step is that all devices in Device Manager which allow power management have that turned off (especially the USB hubs, but really anything).


Do not forget BIOS and Graphics card configuration as well - you want to disable C-State, temporary boosts and anything power management related.

Basically, you don't want battery life - you want all being always on and ready for use.

Note that in this configuration, with a laptop, you may literally need to add cooling (a laptop stand with fans does the job) to avoid CPU throttling due to excessive heat. Always on tends to be hot. :)

Also obviously remove any startup program, services or "call home" taskbar applications that may steal resources and/or interrupt the CPU. Basically you want the bare minimum software running at any given time.

I also assume you run projects at 44.1 KHz sample rate. Higher sample rates with the same 64 sample buffer will obviously require the machine to work harder - same number of samples to process, but less time to do it!

Assuming you've done everything of the above, the CPU is obviously not being the bottleneck here, but then it seldom is.

Most often it's other hardware components in the system, whose drivers are written in a pedestrian manner and thus do way too much work, requiring the constant attention of the CPU. Sometimes it's the inherent design of the machine, for example motherboards slowing down access to memory, slow memory, slow I/O buses, all stuff that simply makes it impossible for the data to flow at a rate compatible with a small buffer. In that case, your machine simply cannot work as fast as required for a 64 samples buffer, and you just need a better one.

But before concluding that, first of all you have to identify the bottleneck, then see if it's possible to remove it. Windows driver architecture is such that a driver will interrupt the CPU for as little time as possible, then if there's more work to do, it will deposit a work package in a queue for later processing. This is the "deferred procedure call" (DPC) queue.

"Bad" drivers create lot of DPCs or, in generally, assume that DPCs don't need to be that optimized because they're not really interrupting the CPU.. but the work needs to be done at some point, and of course Windows needs to prioritize that work over regular applications, so too many (or few, but heavy) DPCs will be disastrous for your poor DAW+synth, which are "mere" applications. It can be as simple as a mouse driver employing stupidly slow calculation methods to retrieve the relative cursor position or stuff like that...

You can use XPerf (download the Windows Performance Toolkit) option or LatencyMon (which should give you an idea) or similar utilities to find if there are drivers which stick out as particularly slow. Check if there are more up to date drivers. Check that throttling is not occurring.

Se what's the minimum size of buffer that doesn't need give you dropouts, to establish a baseline.

I know it's all generic but it's the nature of Windows machines to be all different, so generic guidelines are all that can be given I'm afraid..
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Re: Sorry to ask - clicks n pops on pandemic-imposed laptop

Postby James Perrett » Wed Aug 05, 2020 2:28 pm

Have you switched off Wifi while recording? That's what really helps on my system.
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Re: Sorry to ask - clicks n pops on pandemic-imposed laptop

Postby Darren Lynch » Wed Aug 05, 2020 3:59 pm

Sincere thanks for your considered replies. I was pleasantly surprised that no one said "Daz, RTFM..." Having been away from win PCs for music for so long (12 years on Mac) I expected it all to be user error on my part. So it comes down to the tension between Windows as all things to all users, and audio - which does not play well with others.
CS70's suggestions led me to install LatencyMon. Great little app. I immediately saw the usual suspects crowding at the top of the DPC ranking (NT network driver was top).
For work I have to have wi-fi, firewall, virus protection all active. I'll see what happens when I take the machine completely offline and switch everything off that can be switched off.
Thanks again. You all "most studly".
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