Review and Measurements and miniDSP 2x4 HD DSP and DAC

[TheBatsEar]

I'm talking with a company that claims to improve the measurements through some modifications on the board. They claim all sorts of subjective qualities, but also to reduce THD, N and IMD. The mods are done for a little under 150€, you send your device, they send it back. Given the amount of work, that sounds reasonable to me.

If the measurements back it up, this could be a cheap way to improve the 2x4HDs shortcomings without buying a MiniDSP Flex or SHD.

This is a smaller company and as such doesn't have an AP. So i offered my 2x4HD for modification, if they send it to @amirm for measurement after modification. The companies owner is in and a nice guy to talk to.

I have send Amir a PN, since he needs to be interested as well, obviously.

 

[freemansteve]

Aren't most people looking at the miniDSP more as a band-splitter than a pure DAC?
Typically between main speakers and subs, or possibly to allow removal of passive crossovers in main speakers...

At least that was my interest until my wife saw the Evo.... I was also looking at a pair of Nords, but hey-ho....

 

[johnp98]

Now that the minidsp Flex is out and has a much better DAC but is a bit more expensive my understanding is that the HD is still good (and best bang for the buck) if your just doing subwoofer eq /integration and then flex if your needed the dac component or Bluetooth or Dirac etc?

 

[B&WTube]

Now that the minidsp Flex is out and has a much better DAC but is a bit more expensive my understanding is that the HD is still good (and best bang for the buck) if your just doing subwoofer eq /integration and then flex if your needed the dac component or Bluetooth or Dirac etc?

Everything performing DSP functions, that is outputting Analog is using a DAC. Therefore, the better DAC will still output a better signal. However, if there is a place to sacrifice the top quality signal- it would be to the subwoofer.

 

[TheBatsEar]

Now that the minidsp Flex is out and has a much better DAC but is a bit more expensive my understanding is that the HD is still good (and best bang for the buck) if your just doing subwoofer eq /integration and then flex if your needed the dac component or Bluetooth or Dirac etc?

I think the 2x4HD is underrated, now that the Flex is available. It, with maybe Dirac on top, does more good than harm in my opinion, even for main channels. If your speakers are high sensitivity and in the nearfield you should look at possible background hiss.

Also, the used prices dropped a bit, which makes the 2x4HD even more attractive.

 

[tvih]

Been looking at this for a few days. Problem is that to use it fully with digital inputs I would have to forego surround - as is I'm EQ:ing on my PC and the results are very nice, but of course I can't apply that to my TV's internal apps - since Windows doesn't give 4K and the rest of that good stuff with streaming other than maybe Netflix - or my PlayStations. And while I'm not the pickiest person by any measure, so many finding faults in the sound quality is admittedly a concern since I can't test without buying.

The Flex seems to have less detractors - though then again it's a lot newer product with less users - but the price jumps from ~250€ for the 2x4 HD to 800€ for the Flex in Europe! Doesn't seem there's a version without Dirac here. Not that Dirac would be bad in itself, but when without it the Flex would likely be around 550€ I'm not sure if 250€ for Dirac would even make sense when you can just do the EQ manually with REW and UMIK-1. Plus the total cost of 800€ is very much "oof" since I even started looking at the 2x4 HD as a budget alternative to - or rather to tide me over until - a new AVR for which I'd probably need something like X3700H at 1500€ to get reasonable EQ and also more than two height channels. And while 800€ is less than 1500€, when you factor in losing surround it's just... nope, not gonna happen.

Technically I could still use the 2x4 HD (or regular 2x4, but it's not as good?) with my current surround setup if I use the pre-outs on my AVR to connect my stereo amp for the front speakers instead of using the built-in amplification. I'm not really worried about EQ:ing the surrounds anyway, just the mains and sub - and with a 2x4 HD that means skipping the LFE channel, which I don't mind that much. Bigger problem is doing another analog to digital conversion to achieve it. Plus it's an integrated amp, not a power amp, and doesn't have HT bypass. All of which raises more quality concerns. So many damned volume control stages! *sigh* Although for stereo listening - that of course being the most quality-critical application - I could at least skip the AVR+2x4 HD with a separate connection from the PC to the integrated amp and use the software EQ I'm using now, though that'd mean I'd lose out on the subwoofer. Or only skip the AVR and keep the sub by connecting 2x4 HD to PC directly.)

I guess it's still something to seriously consider given how long it'll take to be able to buy the new AVR - a year at minimum from how things currently look. I just wish I had an opportunity to test the damn 2x4 HD before committing to buy.

 

[TheBatsEar]

If only AV devices would give post decoding digital output. I'm sure somewhere on the board you could grab digital signal before it goes to the DAC, but that's advanced stuff.

Nothing MiniDSP can change.

 

[Chromatischism]

Been looking at this for a few days. Problem is that to use it fully with digital inputs I would have to forego surround - as is I'm EQ:ing on my PC and the results are very nice, but of course I can't apply that to my TV's internal apps - since Windows doesn't give 4K and the rest of that good stuff with streaming other than maybe Netflix - or my PlayStations. And while I'm not the pickiest person by any measure, so many finding faults in the sound quality is admittedly a concern since I can't test without buying.

The Flex seems to have less detractors - though then again it's a lot newer product with less users - but the price jumps from ~250€ for the 2x4 HD to 800€ for the Flex in Europe! Doesn't seem there's a version without Dirac here. Not that Dirac would be bad in itself, but when without it the Flex would likely be around 550€ I'm not sure if 250€ for Dirac would even make sense when you can just do the EQ manually with REW and UMIK-1. Plus the total cost of 800€ is very much "oof" since I even started looking at the 2x4 HD as a budget alternative to - or rather to tide me over until - a new AVR for which I'd probably need something like X3700H at 1500€ to get reasonable EQ and also more than two height channels. And while 800€ is less than 1500€, when you factor in losing surround it's just... nope, not gonna happen.

Technically I could still use the 2x4 HD (or regular 2x4, but it's not as good?) with my current surround setup if I use the pre-outs on my AVR to connect my stereo amp for the front speakers instead of using the built-in amplification. I'm not really worried about EQ:ing the surrounds anyway, just the mains and sub - and with a 2x4 HD that means skipping the LFE channel, which I don't mind that much. Bigger problem is doing another analog to digital conversion to achieve it. Plus it's an integrated amp, not a power amp, and doesn't have HT bypass. All of which raises more quality concerns. So many damned volume control stages! *sigh* Although for stereo listening - that of course being the most quality-critical application - I could at least skip the AVR with a separate digital connection from the PC to the 2x4 HD.

I guess it's still something to seriously consider given how long it'll take to be able to buy the new AVR - a year at minimum from how things currently look. I just wish I had an opportunity to test the damn 2x4 HD before committing to buy.

I'm planning on using the Flex for a stereo setup. My multichannel big-rig will remain powered by a Denon AVR.

 

[tvih]

I "can't" or don't really even need to separate the two, though I do have two secondary systems as well. But the first is the desktop setup (mostly 2.0, but sometimes 4.0 when gaming) and thus can be EQ'd by the PC directly. Though currently I haven't done a curve for it yet, had the mic for about a five weeks now but haven't gotten around to it. While the other is in my bedroom primarily just for helping me fall asleep so not exactly quality-critical. Doesn't even really go below 100 Hz which already does away with the biggest room problems even if they mattered.

That being the case is one consideration in buying the 2x4 HD - once I get the X3700H and assuming the Audyssey MultEQ XT 32 doesn't suck (which would invalidate a big portion of the reason for even buying it...) there isn't really an use case for it with any of my current/planned systems, and I'd probably only recoup like half the cost selling it. But still, it does seem like my only reasonable option for proper EQ:ing from all my sources.

(Of note a slight edit to the initial wall of text: with the existing software EQ I could of course skip both AVR+2x4 HD entirely with PC stereo use, and not just the AVR unlike what I initially wrote... though I would lose the subwoofer in the process. It wouldn't be the end of the world, I had the sub disconnected for a good 8 years until I wanted to test it with the mic. Plus the main speakers can go to 30 Hz at -5 dB on their own, thanks to room reinforcement.)

 

[Chromatischism]

the first is the desktop setup (mostly 2.0, but sometimes 4.0 when gaming) and thus can be EQ'd by the PC directly.

This is my preference as well, but the PC needs the MiniDSP to use a subwoofer properly. You quickly realize that it makes a lot of sense to have the EQ in the same DSP as the bass management.

 

[tvih]

This is my preference as well, but the PC needs the MiniDSP to use a subwoofer properly. You quickly realize that it makes a lot of sense to have the EQ in the same DSP as the bass management.

Yeah, when you have a sub in the mix for a stereo amp system the miniDSP definitely makes sense to get a "clean" crossover result. For me I'm currently doing the desktop surround with two stereo amps which isn't exactly optimal, but once I replace the current AVR in the main system it will be used on the desktop and thus I could use the sub in that setup as well just by switching the cable going to the sub.

The way I'm currently integrating it via the AVR is having the AVR handle the crossover and just driving a full range signal to the mains, and the AVR then redirects the lows below the crossover point to the subwoofer (and for LFE it can be EQ'd separately on the PC though I haven't yet). Running the REW sweeps like that (with the sub's base SPL level matched to the speakers, of course) and then doing the EQ on that result - separately for each channel - and the end result integrates really nicely and I have a quite nice adherence to the Harman curve as the "sum total". But can't do it like that with a stereo amp!

 

[Piere]

If only AV devices would give post decoding digital output. I'm sure somewhere on the board you could grab digital signal before it goes to the DAC, but that's advanced stuff.

Nothing MiniDSP can change.

The MiniDSP 2x4HD actually does. There is a header on the board that spits out I2S audio format for channel 1/2 and channel 3/4. It is at 3V logic level and well described in te manual. You can do 3 things:
1/ Hook up LVDS buffers to external DAC's of your choice with I2S input capability.
2/ Hook up I2S to S/PDIF converters.
3/ Hook up directly the best DAC chips according to your taste. Regarding this, it's a pity AKM burned down a few years ago (my favourites).

No. /3 is by far the most straight forward.

It is indeed advanced electronic stuff but by no means rocket science. I myself will try option 2/ in the near future and see what it brings.

 

[Plcamp]

I myself will try option 2/ in the near future and see what it brings.

I am interested in this!

 

[Chromatischism]

The MiniDSP 2x4HD actually does. There is a header on the board that spits out I2S audio format for channel 1/2 and channel 3/4. It is at 3V logic level and well described in te manual. You can do 3 things:
1/ Hook up LVDS buffers to external DAC's of your choice with I2S input capability.
2/ Hook up I2S to S/PDIF converters.
3/ Hook up directly the best DAC chips according to your taste. Regarding this, it's a pity AKM burned down a few years ago (my favourites).

No. /3 is by far the most straight forward.

It is indeed advanced electronic stuff but by no means rocket science. I myself will try option 2/ in the near future and see what it brings.

So there are 2 outputs, one for channels 1 and 2, and one for 3 and 4?

Let's think about use cases for this.

If only AV devices would give post decoding digital output. I'm sure somewhere on the board you could grab digital signal before it goes to the DAC, but that's advanced stuff.

What would you use it for?

 

[Piere]

Yes, the I2S (Inter Ic Sound) format is the format that actually goes to the DAC chips and always contains 2 channels at the actual sampling rate. My use is for a 4th order Linkwitz-Riley Sub X-Over, Sub processing and minor adjustment for the monitor speakers that handles frequencies from 70Hz upwards. The monitor speakers by itself fall off at 70Hz at 2nd order. And are as such half part of the 4th order X-over.

 

[Chromatischism]

Yes, the I2S (Inter Ic Sound) format is the format that actually goes to the DAC chips and always contains 2 channels at the actual sampling rate. My use is for a 4th order Linkwitz-Riley Sub X-Over, Sub processing and minor adjustment for the monitor speakers that handles frequencies from 70Hz upwards. The monitor speakers by itself fall off at 70Hz at 2nd order. And are as such half part of the 4th order X-over.

You can already do that in the MiniDSP though. Right?

 

[mdsimon2]

I messed around with the I2S output of the 2X4HD a bit last year. I tried two different I2S to SPDIF/AES boards, both based on the WM8805.

Digital Interface I2S to SPDIF AES EBU XLR 110 Ohm for Amanero WM8805 - Audiophonics

Voici une Interface I2S avec sortie soudable vers une SPDIF 75Ohm (coaxial, BNC) ou AES EBU XLR 110 Ohm

www.audiophonics.fr

I2S / USB to AES/EBU / Coaxial / Optical / HDMI Digital Interface 32bit 384kHz DSD128 - Audiophonics

This module will allow you to combine an Amanero or XMOS USB interface (sold separately) to enjoy a complete and versatile digital interface.

www.audiophonics.fr

I could only get it to reliably work with one stereo output, with two stereo outputs I always got a bit of crackling. I could have messed a bit more with wiring (daisy chaining vs splitting on LRCLK, BLCK and MCLK as well termination resistors) but didn't really think it was worth the effort. The pin out of the I2S header is rather poorly implemented with only single connections for ground, LRCLK, BLCK and MCLK.

Two stereo outputs did work perfectly when used with an Ian Canada McFIFO / McDual but that adds a lot of cost and complication.

For reference here is a measurement of the I2S digital output after being converted to SPDIF, obviously this looks very good.

Overall I just don't think it is worth the time, effort or cost to implement.

Michael

 

[Piere]

You can already do that in the MiniDSP though. Right?

True. However, this is about the 2x4 HD

 

[Piere]

........

I could only get it to reliably work with one stereo output, with two stereo outputs I always got a bit of crackling. I could have messed a bit more with wiring (daisy chaining vs splitting on LRCLK, BLCK and MCLK as well termination resistors) but didn't really think it was worth the effort. The pin out of the I2S header is rather poorly implemented with only single connections for ground, LRCLK, BLCK and MCLK.

Two stereo outputs did work perfectly when used with an Ian Canada McFIFO / McDual but that adds a lot of cost and complication.


Michael

Thanks for the warning! The I2S pin header goes straight to the SHARK DSP chip. IMO it needs proper signal high speed layout and buffering for off-board use. The spectrum plot looks promising! My plan is to hook up 2x Topping E30 at first.

 

[TheBatsEar]

What would you use it for?

You could buy a bunch of 2x4HDs and DSP the heck out of every channel.