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

[YoneV]

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!

 

[eclipsevl]

Hi,

have a look at this one:

York DSP devices

Hello, couple of times I posted my projects photos in different threads but I think it is time to create a separate thread. I've been working on the York USB UAC2 interface and then started transitioning into DSP hardware and software. One project is a 4 channel D-Class amplifier for which I...

www.audiosciencereview.com

 

[YoneV]

Hi,

have a look at this one:

York DSP devices

Hello, couple of times I posted my projects photos in different threads but I think it is time to create a separate thread. I've been working on the York USB UAC2 interface and then started transitioning into DSP hardware and software. One project is a 4 channel D-Class amplifier for which I...

www.audiosciencereview.com

Thanks. If you offer 6ch one-neat-box solution, I will more than happy to pay you instead of a corporation for their product.

 

[Koifarm]

I used often PA2 and VENU360.

https://nl.aliexpress.com/item/1005...wzauwlLR&utparam-url=scene:search|query_from:

Nice tablet/ipad control option.

 

[MEGB1262]

Hi there and welcome,

i wonder if you have some kind of measurement system for your project

if not, the Dirac Live extension for the miniDSP will make the measurement and the room correction in one go for you, you have to pay fro the UMIK-1 or UMIK-2 and the DL extension

but it is difficult to find another tool that is so easy to use and make all measurements for you

hope it helps, Stefano

 

[Koifarm]

PA2 and/or VENU360 does also auto room correction/measurement without extra cost.

 

[john61ct]

PA2 and/or VENU360 does also auto room correction/measurement without extra cost.

Can it act as convolver for filters created by REW/ rePhase, Acourate etc ?

Can timing be sync'd between multiple units to get multichannel ?

Seems very suspiciously cheap

Compare to Behringer DEQ2496 Ultracurve Pro ?

 

[YoneV]

Hi there and welcome,

i wonder if you have some kind of measurement system for your project

if not, the Dirac Live extension for the miniDSP will make the measurement and the room correction in one go for you, you have to pay fro the UMIK-1 or UMIK-2 and the DL extension

but it is difficult to find another tool that is so easy to use and make all measurements for you

hope it helps, Stefano

I will be using XLR mic for measurements, along with (most likely) Focusrite Scarlett Solo as interface. USB mic will now allow for phase and timing measurements, as it cannot have a reliable loopback.

My question was not about room correction, rather active crossover with DSP. Dirac cannot help with speaker design. The DSP should have quality ADC/DAC and really low noise floor, as a 109 Db sensitivity compression driver will be used.

 

[Koifarm]

Can it act as convolver for filters created by REW/ rePhase, Acourate etc ?

Can timing be sync'd between multiple units to get multichannel ?

Seems very suspiciously cheap

Compare to Behringer DEQ2496 Ultracurve Pro ?

No and no. It is best buy for money.

DEQ2496 is dac/eq and not active filter, DCX2496 is active filter with eq.
In the past I used both.

Pa2/venu360 are better and easier to use.

 

[YoneV]

Also - any idea for master volume once all is set? I will have Wiim streamer and power amps. Not keen on Wiim as reliable master volume control before DSP processing. Power amps have no native volume control.
MiniDSP flex has the master volume and remote. Helix doesn't.
Any alternative ideas on master volume in this case?

 

[MEGB1262]

Hi there,
if you want to listen with very high quality even at listening levels 40 dB below the peak level you have to consider to have a attenuator stage behind the DAC and before the power amp

if your noise floor is about 107 dB you will have only about 14 bit of the theoretical 24 Bit in the DSP crossover resolution with an attenuation of 40 dB already before the analog input of the DSP crossover

so you have to use the digital attenuator in the DSP crossover itself, or you will end up with CD level resolution with only 10 dB attenuation before the DSP CO

beside this you need some headroom for the music signal, so in my eyes the gain structure with the correct attenuation before in and after the DSP CO is the critical point

- Stefano

 

[john61ct]

I will be using XLR mic for measurements, along with (most likely) Focusrite Scarlett Solo as interface. USB mic will now allow for phase and timing measurements, as it cannot have a reliable loopback.

You meant "will not allow"

amirite?

 

[john61ct]

Wiim Ultra's volume control as preamp is fine.

Dunno about the others.

But if you want to add a dedicated knob into the chain that's fine too.

Also - any idea for master volume once all is set? I will have Wiim streamer and power amps. Not keen on Wiim as reliable master volume control before DSP processing. Power amps have no native volume control.
MiniDSP flex has the master volume and remote. Helix doesn't.
Any alternative ideas on master volume in this case?

 

[john61ct]

Pa2/venu360 are better and easier to use.

I see the original are dbx "Drive Rack" products.

I am suspicious those Ali links might be lower quality knockoffs?

 

[YoneV]

@john61ct - exactly - I meant "will not allow". NO reliable phase and timing measurements with USB mic. Anyway, that is not a problem, XLR mic and good enough audio interface can be had for not that much of expense.

As @MEGB1262 rightfully noted, excessive attenuation before DSP is not a good idea, for processing purposes nevertheless. That's what makes me uncomfortable using streamer volume as master volume, as well as the possibility of sending full power of a 200w/ch amp to a 109db sensitivity compression driver because I just forgot to the lower the volume on the app before hitting play.

As far as I understand (complete novice here) i will be better off sending unattenuated (or not greatly so) digital signal from streamer to DSP, and have the attenuation after DSP (of course after having some attenuation within the DSP to compensate for sensitivity mismatch between woofer and CD), ideally on the analog signal before the amp (again, my ignorance might have kicked in hard here). Inline attenuators at amp input are an option, but that again leaves master volume at streamer or DSP level, albeit with less damage to signal if only streamer attenuation is used.

At this stage (apart from speaker components) I only have the the 4x200w power amp and considering the DSP solution. Might as well get two Hypex Fusion plates and get it done with not much of interconnects

 

[Koifarm]

I see the original are dbx "Drive Rack" products.

I am suspicious those Ali links might be lower quality knockoffs?

I have dbx pa2 from the Netherlands and from Aliexpress and they are the same.
The Ali one cost half the price.

 

[john61ct]

they are the same.

Do you know that from detailed measurements, or identifying the components used on the PCBs?

Or it it just your general impression?

 

[Koifarm]

Same PCB and components, same noise floor. And thats the normal selling price in the east.
They are produced in china and sold in the beginning for $99. In Europe I payed €379 at the same time.

 

[YoneV]

Will a Multi-channel pre-out capable AVR be able to attenuate 4 channel DSP signal into 4 channel poweramp?

 

[john61ct]

Well attenuation (volume control) is by definition what a preamp does. So "pre-out" means yes those signals are affected by the volume control, as well as the decoding and other DSP manipulations.

Will a Multi-channel pre-out capable AVR be able to attenuate 4 channel DSP signal into 4 channel poweramp?