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Author Topic: Still having Convolution + Loopback issues.......  (Read 1147 times)

natehansen66

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Still having Convolution + Loopback issues.......
« on: February 11, 2013, 06:09:07 pm »

I use the Loopback function pretty extensively for Netflix, Spotify as well as REW. It works great when I'm only using the PEQ, which I use for eq and crossovers for my 3-way active speakers. However, when I kick in Convolution I get some dropouts. This happens about once a minute or two.
Convolution works just fine when I'm playing from the hard drive.

I use an Echo AudioFire 12 interface with their ASIO driver. I'm currently using .05 second buffer in MC, and 256 sample ASIO buffer. The Output Format is set to 24 bit and resampling to 48khz. I've tried many different configurations but nothing does the trick. I like to use convolution for phase correction, and I thought maybe the dropouts were due to the FIR filters and related latency issues so I generated some minimum phase room correction filters in REW. Still having frequent dropouts with the Loopback.

With convolution on + Loopback, MC is using an average 6% CPU. With convolution off + Loopback its closer to 1%.

Here's my Benchmark scores:

Running 'Math' benchmark...
    Single-threaded integer math... 4.221 seconds
    Single-threaded floating point math... 2.514 seconds
    Multi-threaded integer math... 4.226 seconds
    Multi-threaded mixed math... 2.518 seconds
Score: 1410

Running 'Image' benchmark...
    Image creation / destruction... 0.332 seconds
    Flood filling... 1.667 seconds
    Direct copying... 2.752 seconds
    Small renders... 2.888 seconds
    Bilinear rendering... 2.783 seconds
    Bicubic rendering... 2.776 seconds
Score: 1667

Running 'Database' benchmark...
    Create database... 0.687 seconds
    Populate database... 2.231 seconds
    Save database... 0.439 seconds
    Reload database... 0.075 seconds
    Search database... 2.072 seconds
    Sort database... 1.459 seconds
    Group database... 1.034 seconds
Score: 2689

JRMark (version 18.0.126): 1922

The math score is fairly low, is my PC not up to the job?
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mwillems

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Re: Still having Convolution + Loopback issues.......
« Reply #1 on: February 11, 2013, 07:27:23 pm »

I use the Loopback function pretty extensively for Netflix, Spotify as well as REW. It works great when I'm only using the PEQ, which I use for eq and crossovers for my 3-way active speakers. However, when I kick in Convolution I get some dropouts. This happens about once a minute or two.
Convolution works just fine when I'm playing from the hard drive.

I use an Echo AudioFire 12 interface with their ASIO driver. I'm currently using .05 second buffer in MC, and 256 sample ASIO buffer. The Output Format is set to 24 bit and resampling to 48khz. I've tried many different configurations but nothing does the trick. I like to use convolution for phase correction, and I thought maybe the dropouts were due to the FIR filters and related latency issues so I generated some minimum phase room correction filters in REW. Still having frequent dropouts with the Loopback.

With convolution on + Loopback, MC is using an average 6% CPU. With convolution off + Loopback its closer to 1%.

Here's my Benchmark scores:

Running 'Math' benchmark...
    Single-threaded integer math... 4.221 seconds
    Single-threaded floating point math... 2.514 seconds
    Multi-threaded integer math... 4.226 seconds
    Multi-threaded mixed math... 2.518 seconds
Score: 1410

Running 'Image' benchmark...
    Image creation / destruction... 0.332 seconds
    Flood filling... 1.667 seconds
    Direct copying... 2.752 seconds
    Small renders... 2.888 seconds
    Bilinear rendering... 2.783 seconds
    Bicubic rendering... 2.776 seconds
Score: 1667

Running 'Database' benchmark...
    Create database... 0.687 seconds
    Populate database... 2.231 seconds
    Save database... 0.439 seconds
    Reload database... 0.075 seconds
    Search database... 2.072 seconds
    Sort database... 1.459 seconds
    Group database... 1.034 seconds
Score: 2689

JRMark (version 18.0.126): 1922

The math score is fairly low, is my PC not up to the job?

I have a pretty different hardware setup, but I previously had lots of skips and pops with loopback+convolution until I turned off large hardware buffers. My current buffer settings are .5 milliseconds with large hardware buffers disabled, and my hardware control panel's buffer is set to 10 ms (but that may not actually be affecting anything).   

I also had strange results (latency, strange sound, etc.) when I was trying to up or downsample things along with convolution.  Have you tried making multiple convolution filters for different sampling rates and using the automatic switcher to avoid having to up or down sample?

Not sure if either of those will help, and, like I said, I have a very different hardware set up (a different sound card, and my JRMark is in the low 4000's on a good day). 

What's the latency like on your convolution filters (how many samples, etc.)?
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natehansen66

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Re: Still having Convolution + Loopback issues.......
« Reply #2 on: February 11, 2013, 08:48:14 pm »

I don't have large hardware buffers selected either. I've tried less taps on the FIR filters, going so low as to start losing LF resolution and that didn't help either. For the hell of it I just switched the Windows default sound device to another card for the Loopback and that didn't change anything, though I didn't think it would.

I've never used the auto sample rate switcher, but after some monkeying around I got it to work. Apparently with the Loopback the default Windows driver sets the sample rate. I set the mobo to 48khz and MC says 48khz input and locks onto my 48khz filter, same for 44.1. Funny thing is, when I set the default driver to 96khz MC input says 96k input, and convolution says "Enabled and Processing 96khz" but the status says not valid. That said, when we use the Loopback we are at the mercy of the default sound device if there's any resampling that needs to be done?! Yet another reason for a JRiver WDM driver........

After doing that the Loopback is working a good bit better, there's still a ways to go though. Any sort of defect in the playback makes me not want to listen at all...........fortunately it's flawless w/o convolution. I don't see how this made any difference though, as I had both souncards that I used as the default device set to 48k which is what I've been building my filters at and what I've always had MC resample too......

I didn't get this PC with audio processing in mind......only web browsing  ::) but it's served me well for a Wal-Mart Acer!
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