Article: Introducing Hang Loose Convolver From Accurate Sound

[mitchco]

Chris, wow! You are too kind! Thank you for supporting my articles here at Audiophile Style for the past 10 years. It has been a blast, and more is yet to come.

 

Kind regards,

Mitch

[mitchco]

4 hours ago, Bill Brown said:

This is exciting!  Brings me closer to getting into DRC with the AU plugin on a Mac running Audirvana (with what appears will be minimal hassle).

 

Bill

 

1 hour 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. 

 

Thanks Bill! As a +25 year pro software developer, this is one of my main goals. Make it easy to configure and operate from a user's perspective. From a developers perspective, creating software that is easy to use takes more time and effort.

 

Good luck on your journey.

[mitchco]

3 hours ago, ASRMichael said:

@The Computer Audiophile will this be available on Linux? Many users here use Linux based systems. I feel Euphony is best sounding for my liking (IMHO). Having convolution functionality with Euphony would be icing on the cake..

 

Hey Michael, yes available on Linux soon. I just need the Linux distro and supported C++ compiler to target a release on.

[mitchco]

2 hours ago, bbosler said:

I'm a big Fan of Mitch's work currently using Audiolense room correction filters he developed for me to use in HQplayer . I see Hang Loose as a big step forward in the evolution of digital processing implementation so looking forward to exploring how it might fit into my system. I applaud Mitch's efforts to simplify the implementation of convolution for the non-geeks. One thing I need to look at, does Hang Loose offer enough things I can't do with the way I'm implementing convolution in HQP to make me try it?

 

My initial question is ,, where does Hang Loose  grab the digital stream? I see Hang Loose is limited to 384K and the Mac pass through is limited to 192K, didn't see what the Windows limit is. For those of us who up-sample to the max rate of our DAC, will Hang Loose limit that ability? Like I said, I use convolution in HQP which does the convolution at the file's native rate and then HQP  up-samples to 16FS.  If Hang loose grabs the stream before it is up-sampled it will work for me as I have no files above a native rate of 192K. Obviously if Hang Loose grabs it after HQP it won't. For those using PGGB to up-sample files to 16-32FS before playback it is a nonstarter.

 

For those using Pure Music or Pure Vinyl software on a Mac which can accept AU and not VST,  the availability of AU plugins is a big +. 

 

Hey Bruce, good to hear from you and thanks for your kind words. I am taking feature requests :-)

 

As far as I know, HQP does not support VST3 plugins. So currently the digital stream for HLC is after the HQP upsample. I don't know what the API capability of HQP is as I haven't looked into it yet. Maybe there is a way...

 

Kind regards,

Mitch

 

[mitchco]

3 hours ago, jrobbins50 said:

I have several questions:

 

1. With a VST3 plugin, does this mean that HAF’s Room Shaper can be loaded into HLC, and then through HQP desktop thereafter, running convolution filters in either HLC or HQP, and then on to Roon?

 

2. How does HLC compare to the new Audiolense Convolver product?

 

3. Can HLC be configured to apply convolution filters for the audio tracks from Netflix, Hulu, Disney+, etc?

 

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

 

These might be @mitchco questions to answer. :) Thanks. JCR 

 

Hi Jeffrey, thanks for your questions.

 

1) No Room Shaper cannot be loaded into HLC. 

 

2) Bernt is one of my DSP Partner's :-)

 

3) Yes, see the System Wide Audio section in the HLC Operations Guide.

 

4) Chris answered that one.

 

Kind regards,

Mitch

[mitchco]

Hi @deneb Thanks! Re: Acourate cpv is Acourate's proprietary filter format. But it is easy to generate the filter format HLC will accept from Acourate in a minute or 2. In Macro 4, select 32 bit stereo .wav format and generate as before. From the Room menu, select Create Acourate for Roon ZIP and that will place all of the filters at different sample rates in a zip file. In HLC, select the zip file and you are good to go.

 

Kind regards,

Mitch

[mitchco]

10 hours ago, LewinskiH01 said:

@mitchco Very glad to see this coming up! Can't say enough good things about you. Your Computer Audiophile Acourate articles inspired me to go digitally active an into Acourate, which I still use. That opened the door into DIY speakers, and your ebook was essential to getting a better grasp on measurements and use of Acourate. And you have always been very helpful on email exchanges. Outstanding member of this community!

 

Where does HLC fit into my system? I have Roon Core in a PC convolving filters to send 4-way stereo to a headless AudioPC with Roon Bridge at the living room, and I operate Roon from the phone app. I listen to files in my library in Roon Core PC and also Tidal streaming into Roon in that PC. I guess HLC plugs into Roon, takes the feed from Roon that is actually Tidal stream or my music files, convolves it with the selected filter, and outputs into Roon again to be sent to Roon Bridge on the AudioPC?

 

Is there a phone app to manage this or should I be at the Roon Core machine (Teamviewer can solve that), or does it integrate with Roon app?

 

Looking forward to learn more! Congrats again!!

 

Best,

Horacio

 

Hi Horacio, good to hear from you! I hope all is well.

 

Currently, HLC standalone app uses either VB-Virtual Audio cable on Windows or BlackHole on the Mac to "loopback" the output of Roon into the input of HLC and the output of HLC to your DAC. This is a 32 bit float lossless connection. Unfortunately, Roon does not support the VST plugin standard, so this is the current method of connection. I am working on options. Also note HLC processes 2 channel at the moment, but will be MCH soon. 

 

Kind regards,

Mitch

[mitchco]

Hi @cfishersorry no info yet, but working on it. Re: HLC, the advantage is to determine which filter you prefer as I will be releasing a "set" of filters. One will be "neutral" and others will have a little more or less bass. more or less treble relative to neutral. The design behind this will come later, but by switching through the filters, one will likely be preferred.

[mitchco]

Hi @Jorgenthanks for the kind words. The answer to your question is yes and yes :-) HLC VST3 and standalone app will run as many taps as can be output from Acourate, Audiolense and Focus Fidelity DSP software programs. Typical output is 65,536 or 131,072 taps.

 

Kind regards, Mitch

[mitchco]

On 5/20/2021 at 12:30 AM, R1200CL said:

So If SGC (Small Green Computer) accepts, this SW could be implementere in the Sonictransporter ?

HLC can be compiled to run on any mainstream Linux distributions is all I can say.

[mitchco]

On 5/20/2021 at 4:28 AM, Jørgen Skadhauge said:

wonderfull, please let me know when your Multichannel HLC is availble. These days I am playing with the new Audirvana Studio which to my ears is even more transparent than the previous 3.5. So right now in Audirvana I upscale the stereo signal and sent it to the AcourateConvolver. With your VST3 files the stereo signal goes through the VST3 for being processed and then upscaled right before going to DAC ? if it is an advantage the signal sent to the DAC could then be a DSD or DXD signal? Merging Technologies likes DSD and DXD. Never tried, but in another simple setup I use a RME ADI2 dac and here I prefer PCM to DSD.

Best  regards,

Jorgen

 

Hi Jorgen, yes HLC is plugged in before the resampler. 

 

 

[mitchco]

On 5/23/2021 at 7:23 AM, R1200CL said:

@mitchco

Can you confirm HLC can or will run headless on Linux with just a web interface ?

Yes, with some work it can. But I have not had a chance to look into what the effort would be.

[mitchco]

Hi @dziemian I don't know the filter file format for Multisub optimizer or miniDSP. I know folks use REW or rePhase to import filters and convert to another file format... HLC takes stereo 32 bit float .wav files either standalone or bundled in a zip.

[mitchco]

Hi @dziemian sorry, I don't know of any tools that can convert biquads into a FIR filter... Maybe the folks at miniDSP can assist?

[mitchco]

2 hours ago, Iansr said:

If I already have JRiver and use its convolver to implement filter settings derived from say AudiolLens, would there be any advantage in buying and using HLC?   This is a genuine question and not an attempt to slight HLC.

 

On my website and in the operations guide describes, "Why Hang Loose Convolver." In the case of JRiver, the VST3 plugin is used for both Mac and Windows versions of JRiver. The setup and configuration is described in the operations guide.

[mitchco]

On 6/28/2021 at 12:36 AM, Confused said:

@mitchco - once HLC is fully set up and running with multiple convolutions installed, what is required to switch between convolutions?  Is it a simple one press of a key an the keyboard, or a click of the mouse somewhere?

 

Yes, mouse click on the big Filterbank buttons to switch filters. I could implement keyboard shortcuts, but I have not looked into it yet.

[mitchco]

On 7/8/2021 at 3:58 PM, Iansr said:

The spec sheet says HLC has zero latency.   Does that remain true if you are using it as a plug-in with JRiver?

Yes.

[mitchco]

@RacerxnetSorry, not yet. It is on my todo list, but I don't have an ETA as I am currently working on other DSP projects.

One can download and install HLC in bypass mode to ensure the entire signal path works for the intended scenario(s). If that works then one can purchase a license key and activate HLC. I offer a 14 day money back guarantee so if it is not to your liking, I will happily refund the entire amount.

 

Kind regards,

Mitch

[mitchco]

Hi @Adrian Waddell Thanks for posting this!

 

Kind regards,

Mitch

[mitchco]

@Iansr working on it, amongst other projects. Don't have an ETA. Will let you know when it comes available.

[mitchco]

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!

 

[mitchco]

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.