Article: Introducing Hang Loose Convolver From Accurate Sound

[The Computer Audiophile]

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[The Computer Audiophile]

17 minutes ago, yyz said:

I would love to have my RAAL SR1a with some convolution options.  Not sure if it would be better but it would be interesting.

 

Oh just wait :~)

[The Computer Audiophile]

6 minutes ago, jrobbins50 said:

4. Sorry, but I’m not clear on the DLNA benefit.  What’s the use case there?

 

I can answer this one. 

 

Many people have DLNA audio endpoints. For example, I have an EMM Labs MA3 right now that accepts DLNA on its Ethernet interface. And, many people use apps that send audio out via DLNA. The high thing missing has always been the ability for an app that supports Qobuz or Tidal to use convolution while sending audio out via DLNA to a DAC / endpoint. Now we can do this by using the HLC convolver VST3 plugin for Audirvana.

[The Computer Audiophile]

41 minutes ago, bbosler said:

 

I'm a bit confused.. There are a variety of VST convolver plugins. I even found an old AU convolver plug to use with Pure Music on my Mac  that was a bit awkward to use but worked. Was it not possible to use any of these VST plug ins before HLC?

 

32 minutes ago, Bill Brown said:

Yes, other convolvers have been around; seems like mostly from the pro sector.  This one could be cool as it will hopefully be easy to use and has been developed by a good friend of the forum/audiophiles. 

 

I have been searching for an answer to this question as I know I read it somewhere, but I can't find it.  The processing order in Audirvana.  Is it upsample then Audio Units or vice versa?

 

Bill

 

There are many possible solutions out there, but every one I tried was problematic. Either it was buggy, not supported because it was VST rather than VST3, or it didn't support very many taps or high sample rates, etc... I searched long and hard for a solution prior to HLC. 

[The Computer Audiophile]

4 minutes ago, deanoUK said:

The Zero latency, uniform partition convolution engine.

More information please.

Huh?
 

 

4 minutes ago, deanoUK said:

I gather you are targeting low end CPUs

I don’t think there is a target. It should happily run on very fast machines as well. 

[The Computer Audiophile]

25 minutes ago, R1200CL said:

@agillis

Hi Andrew.
I like to suggest you looking into the possibility to implement this SW in the SonicOrbiter OS. 
I think it will add a lot of value. 
 

Andreas

+1

 

This would be great. 

[The Computer Audiophile]

38 minutes ago, agillis said:

 

HLC looks like a GUI application that requires a desktop OS such as Windows. Does it run embedded with no screen? That would be required to run on an "headless" device like a sonicTransporter.

It can run on anything. I’m guessing a web interface would work.

[The Computer Audiophile]

5 hours ago, mitchco said:

A couple of updates:

 

1. HLC Linux version available for download. Please send me an email if you wish to target a different distro than Ubuntu.

 

2. Most Digital Audio Workstations (DAW)’s support “automatic delay compensation” when using VST3 or AU plugins that have latency. The idea is that the plugin reports its latency to the DAW and the DAW compensates for the latency. So when tracking or producing audio for video postproduction, the tracks and/or video is delayed by the number of samples reported by the plugin so that the audio lines up perfectly with the video.

 

While HLC is a 0ms latency convolver, some FIR filters have inherent delays, like if using linear phase FIR filters for example. The latency changes based on; type of FIR filter used, sample rate, number of filter taps, how much excess phase correction has been applied, and if using digital xo’s, whether min or linphase. HLC now reports the FIR filter latency to the host for automatic delay compensation:

 

A 131,072 tap minimum phase FIR filter with minimum phase digital XO reports 0 latency samples:

 

A 131,072 tap minimum phase FIR filter with linear phase digital XO reports 5,540 latency samples:

 

A 131,072 tap linear phase filter with linear phase digital XO reports 37,863 latency samples:

 

And if the sample rate changes and HLC does not find a matching FIR filter for that sample rate, then the FIR filter is resampled to maintain its frequency resolution and reports the new latency samples:

 

 

Great for DAW’s, but what about consumer applications? Working with the folks at JRiver, the latest version of JRiver now supports automatic latency compensation. This allows one to use full tap length linear phase FIR filters with excess phase correction and not have any lipsync issues while watching movies.

 

If folks can think of other consumer (or pro) applications that support the plugin model, please send me an email. I can work with the developer to implement automatic latency compensation.

 

Happy listening!

 

So cool!

[The Computer Audiophile]

2 minutes ago, mitchco said:

Hang Loose Convolver (“HLC”) is now available on Raspberry Pi4.

 

Requirements:

Raspberry Pi4 4GB (2GB is likely to work).

64 Bit OS Debian version 11 (bullseye).

 

Performance:

Process 32 channels of convolution using 65,536 tap length FIR filters at 48 kHz sample rate.

 

Example playing a 7.1.4 Dolby Atmos (already decoded) music file using a VST3 plugin AudioFilePlayer. HLC is configured for 12 channels with 2 channel I/O being summed:

 

 

While this example is using a 7.1.4 (12 channel) file being played, the FIR filterset has digital XO’s and bass management built in. So, with 12 channels of direct signal and 11 channels of bass offloading means 23 channels of discrete convolution is being processed. With 23 channels of convolution processed there is still considerable CPU headroom and buffer size left.

 

Note: HLC is a zero latency convolver, meaning no signal delay is added by the convolution engine. Therefore, one can process 65,536 tap minimum phase FIR filters immediately with no added signal delay. This is good for situations where lipsync is required but you still may want high-resolution FIR filtering capability of 65,536 tap length filters.

 

HLC comes with HLConvolverHost, which allows you to plug in virtually any VST3 plugin for additional processing. The simple audio settings dialog allows you to easily choose inputs and outputs, sample rate, and buffer size so you can be up and running in minutes.

 

Updated Operations Guide.

This is fantastic!