PC-based DSP & DAC: Flex 8 or UltraLite-Mk5?

[howard416]

Hi everyone.

I'm wanting to do a stereo 3-way or 4-way (probably the latter) active speaker setup, which will 99% of the time be running from a PC.

For me, I like the idea of being able to run all the DSP built into a single device and not have to learn or manage something like CamillaDSP, but, it sounds like the Flex 8 is not powerful enough to run per-output FIR filtering for linear phase, which is what I'd like to play with. Given that, I might have to run CamillaDSP anyway.

Cost-wise they are both in the same ballpark but the UltraLite-mk5 is a bit more expensive. Neither are cheap of course so this ultimately is not going to be the deciding factor, I think.

The nice thing about the UltraLite is that it also has analog/mic inputs, which I could likely use in future. On the flip side, the Flex 8 comes with a remote (which in the off-chance might come in handy... sometimes).

I'd like to hear anybody else's thoughts, especially if you have experience with one or both in this application.

Thanks in advance!

 

[howard416]

For what it's worth, I want to use the device (either one) as the single, latency-free audio output device catching all audio from Windows (including video games, web browsers/YouTube, whatever streaming apps, etc.)

Based on my current level of understanding, both devices can work this way and it's just a matter of Windows setup to make it happen.

 

[boxerfan88]

Just in case you’re able to find them in any e-shop inventory, check out Topping DM7.

 

[Keith_W]

Here is a blow-by-blow summary of the MiniDSP Flex 8 vs. software based linear phase FIR + Ultralite Mk. 5:

Type of DSP: Flex 8 has mixed phase DSP - min phase IIR + limited linear phase FIR (1024 taps per channel if I remember correctly). Software based can be anything you want, including linear phase FIR with 256000 taps. Linear phase FIR is much easier to design since you can manipulate amplitude independently of phase, and there is an argument that it might sound better since it does not distort phase.

Latency: latency is an unavoidable consequence of linear phase FIR. Since the Flex 8 is incapable of FIR filters with long taps, it will always have less latency. With software based it is up to you to configure the DSP setup as you wish. You can calculate the latency of a FIR filter with (n-1)/2Fs where n is the number of taps and Fs is sampling rate. So, for 65536 taps at 48kHz, the latency is 0.682 seconds.

Flexibility and convenience: both Flex 8 and Ultralite have digital inputs, but the reality is that routing these inputs into your convolver with software is not easy. Sometimes changing inputs might require a few steps. I have to give it to the Flex 8 for convenience. However the software based solution is far more flexible. Having an interface means you can do a LOT of things not possible with a Flex 8 - like record music, perform ADC, use more DAC's, etc.

Robustness: software based DSP is only as robust as the PC you are running it on. One bad Windows update and your playback chain is broken. You can get around this by running it on a Pi or a dedicated PC not connected to the internet, e.g. a Linux based PC dedicated to running the convolver. Also, the Flex 8 powers up almost instantaneously. You know how long it takes a PC to boot up. Again I have to give it to the Flex for this one.

 

[ppataki]

If you know your way around software DSP (e.g. Jriver and various VST plugins) then go for the Ultralite (or even better, the DM7 but very sadly it was discontinued)
It will provide much greater flexibility. Personally I am a huge fan of linear phase filters and hence I went that way too
MiniDSP would be easier to manage though
(less steeper learning curve)

 

[charlielaub]

If you buy the MiniDSP you are married to that platform for everything. If you use software plus an audio interface (like the MOTU) you have the flexibility of changing/upgrading the parts at any time e.g. get a new computer or software, upgrade the audio interface when a better one comes along, or start with a cheaper audio interface and then decide later if a more expensive one is worth it (e.g. I have used the Behringer UMC1820 - it's cheaper and it is not bad at all). Also, you have the option of using a balanced interconnect with these audio interfaces if noise or hum pickup is ever a problem. Although you will be more down in the weeds in terms of the initial setup, you will have much more flexibility and more FIR capability when you go this route. Also, if you will just be playing or streaming music, you could get a dedicated Linux box that will handle all the audio stuff and keep the Windoze away. I did that a long time ago and am now only using Ubuntu for anything audio in my home. I have a Windows 11 desktop computer for "work" and so on, but I keep that separate. All software that I use under Linux is free and I can re-image or do whatever, ad nauseum, if I desire. You get even more freedom in that!