miniDSP vs Helix vs... as DSP options for 2ch DIY speaker project

[Flaesh]

I got the Flex8. As a simple, ready-made solution for my 15"+WG. But I have two-way tweeters and two subwoofer channels, a 9-meter delay is a must for me.
USB input, volume control and remote contro, quite quiet. The latter is important, especially for compression drivers connected directly to amplifiers.
It's a shame there aren't balanced outputs like the old 4x10. FIR is only on the input, with limited capabilities; I haven't tried it. And yes, I would have liked a lower price)).
What horn\WG and driver will you use?

 

[john61ct]

for my 15"+WG

Warehouse Guitar gear? Waveguide?

 

[YoneV]

I got the Flex8. As a simple, ready-made solution for my 15"+WG. But I have two-way tweeters and two subwoofer channels, a 9-meter delay is a must for me.
USB input, volume control and remote contro, quite quiet. The latter is important, especially for compression drivers connected directly to amplifiers.
It's a shame there aren't balanced outputs like the old 4x10. FIR is only on the input, with limited capabilities; I haven't tried it. And yes, I would have liked a lower price)).
What horn\WG and driver will you use?

FaitalPro 15PR400 + FaitalPro HF146 + 18Sound XT1464 horn - these are sorted.

miniDSP Flex should suffice for me.

Right now I am assembling 4ch power amp (https://www.diyaudio.com/community/threads/2x150w-amp-module-for-sale.388868/) - 2xFFA001V4. But that has 200w per channel, so I am concerned I will need too much output attenuation at DSP level. This (if a problem) might be solved with an old multichannel input / pre-out just for (remote) volume control, but these old AVR monsters are huge and this requires helluva lot interconnects. Also, such AVR is almost mandatory with the Helix, as there is no remote volume control there and leaving all volume control up at streamer is a no-go in my mind.

Total mess

Might as well get two Hypex Fusion FA122 and get it done.

 

[Redacted]

I don't know much about this, so feel free to savage me, but I'm wary of a ADC->digital filter->DAC process, as it seems like a lot going on with all those stages, and maybe more money.

Is there not a means to take digital source files (eg FLAC), send as spdif, apply digital filters to get 2x 2 channel or more, and then apply a DAC and amp to each of the 4 (or more) bands to each speaker driver?

 

[YoneV]

Is there not a means to take digital source files (eg FLAC), send as spdif, apply digital filters to get 2x 2 channel or more, and then apply a DAC and amp to each of the 4 (or more) bands to each speaker driver?

miniDSP and Helix do take digital source, apply digital filters, apply DAC and send each of the 4 analogue bands to an amp - all in one box.

 

[Flaesh]

ADC

I never used analog inputs; I always bought processors with digital inputs. But devices without digital inputs are common, including processors and active speakers with DSPs after the ADC.
ps: Including in cheap products, because they're cheaper with an ADC. Yes, that's right. I spoke with a studio monitor designer.

Waveguide?

From the context, it seemed obvious it was a waveguide. You can see it on the left, above my nickname. SEOS24.

 

[Redacted]

miniDSP and Helix do take digital source, apply digital filters, apply DAC and send each of the 4 analogue bands to an amp - all in one box.

Aha, good! I looked a while back and the 2-in & 4-out miniDSP unit was analogue only, IIRC - they must have added the digital in (spdif, I assume).

It would be nice if they offered 4x digital out by some means so you can run your own DACs.

 

[Flaesh]

run your own DACs

Just a multi-channel DAC with a USB input and a computer for processing.

 

[Mark185]

Hi,

I am designing active 2 way PA speakers for home hifi (15" woofer with horn loaded CD), DIY 4ch class D power amp (RCA or XLR inputs I/O), but still have to decide on the DSP.

I have been looking at Helix DSP for this project. They are highly regarded in the car audio community, the demo software is impressive. Helix does not have FIR but has 30 band EQ per channel. And is significantly cheaper in Europe compared to miniDSP Flex series.

Options considered are:

Helix DSP.3S (8ch) at about EUR 400
Helix DSP mini (6ch) at about EUR 300
MiniDSP Flex (4ch) at about EUR 650
(wild option - this Ali thingi - https://www.aliexpress.com/item/1005006600879188.html at about EUR 350)

The Helix has unspecified BurrBrown DAC/ADC, nice and extremely flexible software, extensive 30 band IIR EQ, RCA outputs at 6v. The DSP.3S has coax (max. 192 kHz) digital input in SPDIF (may be irrelevant as all processing is at 92kHz). Apart from the channel output (6 vs 8) and coax input, the two Helix devices should be identical. REW integration should be seamless.

miniDSP Flex is well regarded, extensive info for DIY projects, but more expensive. Has FIR filtering but not sure if that will make significant difference compared to Helix. 10 band EQ per channel.

My source will most likely be the trusty Wiim Pro - optical and coax outputs.

The Ali one is just a wild option, seems ok on paper, especially with the ES9028 DAC but no real feedback and no way to test software before buying, only 512 taps for FIR.

I do not want to go CamillaDSP/Raspberry route - seems too complicated for a beginner and I like the one-neat-box solution miniDSP/helix provides.

So has anyone tried using the Helix for home audio, tech wise seems like a good option, especially considering the price markup of the miniDSP route.

Cheers!

Very interesting topic and discussion. I own and have experience with most of the devices in this thread. My choice is the Helix for two reasons:

• The PC software support is best in the business. They update it regularly as needed and you will never be stranded with a device with no software support a year or two after buying it. (common scenario with Aliexpress devices)
• Helix does have an excellent wired remote that could be adapted to home installation if you know how to run wiring. Helix may also have bluetooth remote capability by now but I am not sure about that.
• The higher priced Helix units have very good ADC and DAC chips.

Something else to consider. Most of these DSPs use Analog Devices DSP chips. The underlying capabilities for tuning, crossover, time delay, auto-tune for speakers, etc are all part of Sigma Studio, the free development software from AD. Forum member @eclipsevl is developing hardware using Analog Devices chips and writing software to control them and has ambitious plans to expand what he will offer. I already have purchased his York DSP board and York USB interface board for experimentation. He has hinted that an 8 channel board with higher quality DACs is in the future. I think that is worth waiting for based on my experience to date.

 

[DatSpeakerTho]

I don't know much about this, so feel free to savage me, but I'm wary of a ADC->digital filter->DAC process, as it seems like a lot going on with all those stages, and maybe more money.

Is there not a means to take digital source files (eg FLAC), send as spdif, apply digital filters to get 2x 2 channel or more, and then apply a DAC and amp to each of the 4 (or more) bands to each speaker driver?

This is how all active monitors with dsp handle it, and those are some of the best sounding speakers out there. Multiple conversion stages are fine as long as they are clean.

 

[Luvchampagne]

I don't know much about this, so feel free to savage me, but I'm wary of a ADC->digital filter->DAC process, as it seems like a lot going on with all those stages, and maybe more money.

Is there not a means to take digital source files (eg FLAC), send as spdif, apply digital filters to get 2x 2 channel or more, and then apply a DAC and amp to each of the 4 (or more) bands to each speaker driver?

Yes. And you will spend more money because now you need a multi channel dac with dsp. Closest thing off the shelf is minidsp htx. $1400. Better? Or okto but you only get basic dsp.
4 or more bands is 8 output channells +.
RME has some pro audio gear that are 8 + channels but not really designed to do heavy dsp.
Most higher end dsp have fairly transparent adc dac conversions. Can't remember the source of the info but it is something like 5 adc dac cycles and still well above 100db sinad
Your speakers are orders of magnitude higher in distortion. So inaudible. Not basically inaudible.
If you want to throw money around then you can feel good about minimizing your adc dac cycles.

 

[Redacted]

This is how all active monitors with dsp handle it, and those are some of the best sounding speakers out there. Multiple conversion stages are fine as long as they are clean.

Well, yes, I know, but why not send digital direct to active monitors/speakers? I know some do. This seems cheaper to me, and less noise going in compared with a line-level analogue cable...

 

[Mark185]

Over on diyAudio, member uri-chy has designed PDAC-100D boards based on ADAU1452 that have direct digital feed to Texas Instruments class D amplifier chips all on one board. Each board has 3 channels with ability to add a fourth channel. This would yield 8 way system and is very affordable and no DAC is needed. The key is you have to have some skill with Sigma Studio if you want to do room equalization. The delivered software includes active crossovers. He also has a bluetooth input board if I recall. I have the basic PDAC-100D and am very impressed. You can find his products on Ebay.

https://www.ebay.com/itm/397933098245?itmmeta=01KV8P009FNSSEJ666VJYW50A5&hash=item5ca6a93505:g:afYAAeSw7pFqAL9X

https://www.ebay.com/itm/397932667350?itmmeta=01KV8P009F73W69H2JDC977NAH&hash=item5ca6a2a1d6:g:5nMAAeSwSptqAJ-X

He has also documented the design in great detail and always responds to questions. Here is link to his thread:

3 Way DSP Amp, PDAC-100D

3Way Amp board schematic. ESP32 optical input/output board schematic. External view of the PDAC-100D board and I/O optical SPDIF & ESP32 board. Basic projects in Sigma Studio attached to the message.

www.diyaudio.com

 

[john61ct]

These projects are always exciting to me!

But I want line-level let me use my existing amps!

I don't want to pay for power amp circuitry I won't ever use.

Much rather pay more for Moar channels DSP, across enclosures mine have only one driver anyway

 

[Mark185]

These projects are always exciting to me!

But I want line-level let me use my existing amps!

I don't want to pay for power amp circuitry I won't ever use.

Much rather pay more for Moar channels DSP, across enclosures mine have only one driver anyway

My response was for @Redacted

 

[john61ct]

And I was not addressing any member in particular?

Hoping to stimulate suggestions new to me, from anyone!