New: Hang Loose DSP Processor

[DWPress]

Sorry, I don't think Mac even makes a laptop with an optical drive anymore.

Edit: I was inferring that the audio pipeline in Mac OS is so much easier to work with than Win or Linux. Even though I run streaming, XO and convolution for my audio on my computer I'm rarely concerned about OS updates breaking things. With all the beta testing I do for audio apps there's already enough chance for unexpected surprises....

 

[mitchco]

The FPGA is used to configure and connect the electronics to the software. It allows for features like take a TOSLINK input through DSP and output via USB output for example. Allows for remote firmware updates to the unit itself adding new features/capabilities.

SHARC DSP can be used for low level signal processing as required and for additional flexibility. The CM5 powers the main DSP processing in software.

HLP comes preinstalled with over 50 DSP audio plugins, and the capability to host any one of the thousands of audio DSP plugins on the market, so it is much more than just convolution

Also allows installation of music players if one so desires, like JRiver for example, can run on the Raspberry Pi with no issues and there is 2x M.2 slot (1 per CM5) with PCIe 1x for NVMe (SSD) storage expansion if you wish to store your music locally.

While Linux audio can be daunting it was chosen as it alleviates one of the main issues with Windows and Mac audio installations when it comes to running local audio loopback. ALSA loopback and the specialized ALSA back end engine in HLP software eliminates any clock drift issues and provides robust automatic sample rate switching for the convolver and plugins.

All DSP software is preinstalled, configured, and running before the unit is shipped. Unlike other hardware DSP audio devices, this comes with Raspberry Pi Connect which allows remote connection to the unit anywhere in the world to quickly resolve any technical issues.

 

[EJ3]

Sorry, I don't think Mac even makes a laptop with an optical drive anymore.

Edit: I was inferring that the audio pipeline in Mac OS is so much easier to work with than Win or Linux. Even though I run streaming, XO and convolution for my audio on my computer I'm rarely concerned about OS updates breaking things. With all the beta testing I do for audio apps there's already enough chance for unexpected surprises....

Mine are from 2012. I have no problem keeping old ones running or refurbishing them to my needs. But I had never heard of MAC's having those capabilities.
If they did, I'd likely hunt one down.
I guess that I now have something to investigate.

 

[welwynnick]

I thought that it would be good and unfortunately put it on one of my laptops, fully expecting to be able to play Blue Ray & 4K disks (my laptop was capable of that with Windows 10 (which I unfortunately had deleted) out of my HDMI port.
But I have yet to find a good way to play Blu Rays & 4K disks with LINUX. So, for me LINUX sucks because all it caused was for me to have hate for Windows AND now Linux.
Stability issue: I just block the Windows from updating until I want to update it. But, I had been assured by Linux folks that I could play those disks. The Linux programs that supposedly will (at least that I have tried) has serious issues and won't.
If you know of any Linux programs that actually do work to play Blu Ray & 4K, please let me know.
I was really gung ho about getting out of the Windows Universe but became severely disappointed instead.
I'm so happy that I did NOT change my desktop or my other laptop tablet computers so that they could not play these disks, either.

I don't think you can play 4k Blu-rays on PC any more, either.
If my fuzzy memory serves me correctly, your CPU needs something called SGX (software guard extension) that was ditched some time ago. Plus an old version of Windows.
Unfortunately you need a recent CPU with TPM2 and UEFI secure boot in order to run Win 11.

 

[welwynnick]

The FPGA is used to configure and connect the electronics to the software. It allows for features like take a TOSLINK input through DSP and output via USB output for example. Allows for remote firmware updates to the unit itself adding new features/capabilities.
SHARC DSP can be used for low level signal processing as required and for additional flexibility. The CM5 powers the main DSP processing in software.
HLP comes preinstalled with over 50 DSP audio plugins, and the capability to host any one of the thousands of audio DSP plugins on the market, so it is much more than just convolution
Also allows installation of music players if one so desires, like JRiver for example, can run on the Raspberry Pi with no issues and there is 2x M.2 slot (1 per CM5) with PCIe 1x for NVMe (SSD) storage expansion if you wish to store your music locally.
While Linux audio can be daunting it was chosen as it alleviates one of the main issues with Windows and Mac audio installations when it comes to running local audio loopback. ALSA loopback and the specialized ALSA back end engine in HLP software eliminates any clock drift issues and provides robust automatic sample rate switching for the convolver and plugins.

Many thanks Mitch.
Unlike with a PC, I don't think the use of Linux in the HLP is an issue,
Will the CM5 power multi-channel processing in the future, as well?

 

[ShadowBoxer]

Unfortunately, you need a recent CPU with TPM2 and UEFI secure boot in order to run Win 11.

There are some fairly easy ways to work around that.

 

[EJ3]

I don't think you can play 4k Blu-rays on PC any more, either.
If my fuzzy memory serves me correctly, your CPU needs something called SGX (software guard extension) that was ditched some time ago. Plus an old version of Windows.
Unfortunately you need a recent CPU with TPM2 and UEFI secure boot in order to run Win 11.

There are some fairly easy ways to work around that.

The Blu-ray video format is a high-definition optical disc format designed to store large amounts of data, primarily used for video content. It offers significantly higher storage capacity compared to DVDs, with a single-layer Blu-ray disc holding up to 25GB of data, and a dual-layer disc supporting up to 50GB. The format is capable of providing high-definition (HD) and ultra-high-definition (UHD) video, often at 1080p or 4K resolution. Blu-ray discs typically use the MPEG-2, H.264, or HEVC video codecs, with accompanying DTS or Dolby TrueHD audio formats.


Windows 10: Playing Blu Ray & 4K: NOT an ISSUE IF you have the correct drives:

Here's how to get it:

• Download the PowerDVD trial from the CyberLink website. Yes, it's a trial, but don't worry, it works great for now.
• Install the software and launch it.
• Insert a Blu-ray disc and PowerDVD should automatically launch and play the movie.

PowerDVD offers some great features like 4K video playback when you watch blu ray discs from Windows 10, HDR, and even a built-in screen recorder. After trying it out, you can even purchase a key to activate it. However, the free trial does have some limitations. You won't be able to save any changes to your Blu-ray discs, and it only works for 14 days. After that, you'll need to purchase a key to unlock full functionality.

MPC-HC with LAV Filters - this one might sound a bit more tech-savvy, but, it's still pretty easy. You'll need to:

• Download MPC-HC (Media Player Classic - Home Cinema) from the MPC-HC GitHub page.
• Download LAV Filters from the LAV Filters GitHub page.
• Extract the LAV Filters zip file to a folder on your computer (e.g., C:\LAVFilters).
• In MPC-HC, go to Settings > Options > Internal Filters > LAV Audio Decoder and select the path to the LAV Filters folder.
• Insert a Blu-ray disc and MPC-HC should launch and play the movie.

Note that this method requires some technical know-how, and you'll need to install and configure the software yourself. But hey, it's free!

 

[mitchco]

Price: USD$2700.

Wow, that is very reasonable considering all the things this unit can do. That's the stereo version though, I am guessing the 8ch or 16ch version will cost more. Can a stereo processor be upgraded to multichannel after purchase?

Hi Keith thanks. While this is a stereo unit, please note for USB, the unit provides 8 channels of I/O. So it is possible, for example, to select the stereo TOSLINK input (or any input) and then 8 channels of USB output to be used for a stereo 3-way or 4 way digital XO system. Or up to 7.1 multichannel surround. Also note HDMI up to 8-channel 192kHz/24bit PCM and 6-channel DSD64 audio extraction.

 

[DWPress]

8 channels of USB output to be used for a stereo 3-way or 4 way digital XO system.

Any chance of a native 8ch+ HLP in the future? In the above scenario I would still need my Okto to act as an 8ch DAC following the HLP. The advantage of course is freeing the system from being tethered to a computer + ADC + mic interface.

 

[welwynnick]

Any chance of a native 8ch+ HLP in the future?

Confused? Isn't that what Mitch is suggesting it will do saying "HDMI up to 8-channel 192kHz/24bit PCM", which is definitely an input?
But wouldn't a stereo input and 8 Ch output best meet your system needs anyway?
Or are you saying you want more than 8 input channels? That's presumably what the 16 channel version will be for? (though I'm curious what the I/O might be?)

In the above scenario I would still need my Okto to act as an 8ch DAC following the HLP.

That's the whole point, isn't it? The best DSP and the best DAC in the separate boxes that do it best?

 

[DWPress]

That's the whole point, isn't it? The best DSP and the best DAC in the separate boxes that do it best?

Yes, but was hoping for an onboard DAC with native 8ch TRS output to eliminate my Okto from the signal chain.

 

[welwynnick]

Yes, but was hoping for an onboard DAC with native 8ch TRS output to eliminate my Okto from the signal chain.

But then you'd have an AVP in all but name. And then someone would ask for Dolby decoding, and it would never end.....

My idea of uncompromised audio is to have a layered architecture where each function has it's own layer, served by the device that does it best (not necessarily expensive)

The HLP is clearly level 3, and the advantage is that you're not compromised by AVP DSP, but you're spared from having to use a PC to do it.

There are lots of fantastic multi-channel interfaces / converters like Antelope, Okto, Apogee, Merging, RME, MOTU or Lynx that have recording studio performance, but reasonable price, certainly compared with high-end AVPs.

 

[kifeep]

Also note HDMI up to 8-channel 192kHz/24bit PCM and 6-channel DSD64 audio extraction.

But then you'd have an AVP in all but name.

I notice that the HLP also has HDMI out. Curious if this will pass video or if it's audio only. If it does pass video, then being able to delay the video to match filter latency would be a killer feature.

Maybe that would also count as an AVP in all but name. But if you want to use the same system for music and video, as I do, then the latency of FIR filters is a real sticking point. I'm considering something like the forthcoming miniDSP Tide 16 for exactly this reason, but would prefer to not get locked into hardware-based Dirac licensing. I also don't need or want most of the other stuff that gets bundled into AVPs.

Or maybe someone should develop a box that does nothing but provide variable video latency over HDMI. There are just too few options for doing any sort of convolution in a system that includes any video.

 

[john61ct]

Just use a PC for the video? lots of players have variable delay

 

[kifeep]

Just use a PC for the video? lots of players have variable delay

When I last looked, I couldn't find anything that both supported major streaming services and had a good ten-foot user interface. Been a while, so it might be worth it to have another look.

To get back on topic, several posts in this thread are about the frustrations of using a PC for audio convolution and the preference to handle it in a separate dedicated box. The same goes for using a PC as a video source.

But also, I read the HLP specs a bit more carefully and saw this:

HDMI Audio​

• HDMI 2.0a input and output (up to 4K 60Hz)
• 12-bit deep Full HD, Full 3D, HDR and 4K 60Hz video supported
• Up to 8-channel 192kHz/24bit PCM and 6-channel DSD64 audio extraction

"Full HD, Full 3D, HDR and 4K 60Hz" doesn't make a lot of sense if the unit does not pass video through to the HDMI output. And if an intended use is to place the unit between a video source and a display, then adding latency to the audio (due to FIR filters) without also delaying the video signal would be an unfortunate omission.

 

[mitchco]

@kifeep yes, video does pass through to the HDMI output.

Wrt FIR filters, while linear phase FIR filters introduce latency, especially room correction filters using excess phase correction, there are also minimum phase FIR filters that do not have any inherent latency. So a high-resolution 65,536 tap minphase FIR filter has 0ms of delay.

HLP uses a zero latency convolver (i.e. direct convolution) and does not introduce any processing delay. In practice, end-to-end delay is dominated by the audio I/O buffer. For example, a 256-sample buffer at 48 kHz is about 5.3 ms.

This is how it's possible to watch movies or play video games with minimal latency. Long minimum-phase FIR filters can still deliver excellent low-frequency resolution while keeping latency practical.

 

[welwynnick]

Thanks Mitch, that was really useful, I thought it was all FIR filters that introduced time delay.

Does the zero delay only apply to using minimum phase FIR filters on the HLP, or are PCs the same?

What happens if you use linear phase IIR filters?

 

[Keith_W]

Thanks Mitch, that was really useful, I thought it was all FIR filters that introduced time delay.

Well the reality is that EVERYTHING introduces some latency, the question is how much. For e.g. if you output from a streamer into a DAC, there is latency - but it is in the order of microseconds to milliseconds at worst. As for FIR filters, there are two types - minimum phase (zero FIR filter latency) and linear phase (constant latency, but dictated by number of taps and sampling rate). There's also mixed phase which is somewhere in between. Note we are only talking about filter latency, there is also processing latency, buffer latency, and so on.

Does the zero delay only apply to using minimum phase FIR filters on the HLP, or are PCs the same?

Linear-phase FIR filter latency is a mathematical requirement caused by the position of the impulse along the delay line. Think of a FIR delay line as a series of taps that move over a sink (the output). A linear-phase FIR has the impulse positioned midway across the delay line, so the taps have zero output until half the series of taps have passed over the sink. OTOH a minimum-phase FIR has the impulse positioned at the start, so the taps produce maximum output at the start of the delay line, and zeros until the end. In other words, FIR filter latency is the same no matter what processor is used. It's fixed by the number of taps (more taps = more delay) and sample rate (higher sample rate = the faster the sink moves). The relationship is: delay (seconds) = (sample rate -1) / (2x Sample rate).

 

[mitchco]

Well the reality is that EVERYTHING introduces some latency, the question is how much.

Depending on the setup, you can precisely measure that using tools like Round Trip Latency Utility: https://oblique-audio.com/rtl-utility.php

I tested that here on ASR using an older Lynx AES16e card in a 2nd computer. The results are:

Bypass mode - meaning no convolution, just pass through HLHost application @ 48 kHz = 14.875ms.
Convolution engaged with a 262,144 taps minphase FIR filter @ 48 kHz = 14.896ms.

The measurement results show there is effectively no filter delay or convolution processing delay as compared to pass through. The RTL measurement includes all I/O buffers in the test loop.

Note: For film, acceptable lip sync is considered to be no more than 22 milliseconds in either direction.

What happens if you use linear phase IIR filters?

Please send me one I will measure it

 

[Keith_W]

What happens if you use linear phase IIR filters?

I missed that part. It is fiendishly difficult to design a linear phase IIR filter. I forget what the method is called, something about reversed subtractive filtering. But it will have the same problem as linear-phase FIR filters. Linphase filters are acausal, meaning it can act on past, present, and future inputs (in contrast, a causal filter can only act on present and past inputs). The "future" input does not imply time travel, it only knows what the future is because the future has been delayed by the filter If you want an acausal filter, you MUST have a delay.