Minidsp U-DIO8 USB to AES Converter Review

[UliBru]

Hello Uli,

I use Audiolense(aware you are the creator of Accourate) and keen to understand how DSP software such as Accurate or Audiolense see the UDIO-8 when it comes to routing channels when measuring for digital crossovers.

I just learnt how to route channels in Jriver is it the same concept? Or is each channel output already designated with a its fixed channel and its matter of numbering them as an output channel prior to measuring?

Just a point in the right direction can potentially get me started in understanding how its done.

Basically the channels can be assigned and routed arbitrarily. But this does not make sense.
Of course I can tell you about the underlying concept in Acourate:

Simply imagine you have directly connected your left and right tweeters at channels 1 and 2. Furthermore the tweeters are also directly connected to the amplifier outputs without passive components in between. Everything runs well when you play music thru the convolution engine with digital crossovers.
But for some reason you decide to test another player, e.g. Foobar. Now channels 1 & 2 are the standard outputs with every player. And thus you play the full signal without XO by the tweeters. Because of the low frequencies the tweeters may announce the end of their life by pretty nice smoke signs

So clearly it is better to connect the bass drivers to channels 1 & 2.
Acourate thus uses the connection scheme bass left, bass right, mid left, mid right, tweeter left, tweeter right starting from channel 1. This is IMHO the safest way.

JRiver allows you to define the channel assignment in the config file also in an arbitrary order. But carefully think about.

I do not use Audiolense for good reasons . So you have to check by yourself how the channels are assigned there.

 

[redGA2SFCA]

I'm contemplating buying the Minidsp U-DIO8 for a future 3 DAC active setup using Acurate and JRiver. I understand the UDIO8 converts and manages 1 USB input and output 4 stereo spifs but Im wondering why isnt there a device that inputs USB and Outputs 4 USB. Is USB not a superior format to spif? Would a basic USB hub perform the same functions and the UDIO8, is a USB hub with these capabilities available?

 

[Vincentponcet]

I'm contemplating buying the Minidsp U-DIO8 for a future 3 DAC active setup using Acurate and JRiver. I understand the UDIO8 converts and manages 1 USB input and output 4 stereo spifs but Im wondering why isnt there a device that inputs USB and Outputs 4 USB. Is USB not a superior format to spif? Would a basic USB hub perform the same functions and the UDIO8, is a USB hub with these capabilities available?

USB is not just an audio transport, it is a data transfer protocol, ie it requires to have a computer to control the flow and negociate with the connected equipement
Nothing would be prevent it to exist to have such an audio usb hub, but it would need a computer in the middle, or at least a microcontroller.

 

[Kal Rubinson]

I'm contemplating buying the Minidsp U-DIO8 for a future 3 DAC active setup using Acurate and JRiver. I understand the UDIO8 converts and manages 1 USB input and output 4 stereo spifs

They also have a version that has 4 stereo AES/EBU outputs.

Nothing would be prevent it to exist to have such an audio usb hub, but it would need a computer in the middle, or at least a microcontroller.

A computer as the source will do.

 

[redGA2SFCA]

Ive read and heard that USB is a better interface for sound quality, is this necessarily true? Thanks for the quick reply.

 

[phoenixdogfan]

Does anyone know a simple class compliant USB to S/PDIF (or AES/EBU) interface that's at least stereo? These seem to be ridiculously expensive for something a lot less complex than a DAC.

Topping D10.

 

[Kal Rubinson]

Ive read and heard that USB is a better interface for sound quality, is this necessarily true?

Better than what?

 

[Trdat]

A very logical question but I thought ill ask just in case there was an answer that I had no idea about. So technically with the UDIO-8 I have 4 stereo channels out or 8 channels output. I have already used them all up for my triamp system with dual subs if I need another one(say centre or surrounds) how do I get two extra channels? or more... Or not possible, which is what I am presuming the answer is...

 

[Kal Rubinson]

A very logical question but I thought ill ask just in case there was an answer that I had no idea about. So technically with the UDIO-8 I have 4 stereo channels out or 8 channels output. I have already used them all up for my triamp system with dual subs if I need another one(say centre or surrounds) how do I get two extra channels? or more... Or not possible, which is what I am presuming the answer is...

I am wondering if multiple UDIO-8s can be synched in the same way that multiple Okto DAC8s are said to be.

 

[Trdat]

I am wondering if multiple UDIO-8s can be synched in the same way that multiple Okto DAC8s are said to be.

Ill be keen to know if there is a way.

 

[tifune]

OK, I just sent it you. You are right that I usually use the other measurement but that is for analysis of DAC analog output, not digital streams.

Sounds good. Please send us the file to [email protected] and we'll take it from there.

We indeed used a different method, I guess similar method as per APx jitter documention and to what you're typically doing for all DAC I guess e.g. Jitter Noise & Spectrum (E.g. below). Not sure how to get that specific new measurement as we haven't seen it before..

was this ever resolved?

 

[mdsimon2]

was this ever resolved?

I am not sure there was ever an issue to resolve here as evidenced by Amir's comments regarding the performance of the Matrix DAC with the U-DIO8 and the D10 as inputs.

Did you try the D10 in this configuration? Maybe with a simple spdif/AES inline passive converter, or directly in the spdif input of the matrix?

I did. Oddly it produced 1 dB less SINAD than minidsp. The issue is that the D10 outputs S/PDIF and the minidsp produces AES. I think the handling of each interface is different in Matrix so it is not a comparison of source devices. There are enough unknowns here that I did not want to post the results and bring attention to it. But here I am doing that....

All evidence presented to date suggests that the U-DIO8 performs just as well as the D10 when coupled with a DAC despite the fact that the D10 has better jitter measurements.

Michael

 

[Trdat]

I am wondering if multiple UDIO-8s can be synched in the same way that multiple Okto DAC8s are said to be.

So an email back from minidsp says no simple way to add more channels. But, I just realised that I can use a RCA splitter(just a guess but I am sure it will work) and get an extra channel with the same frequency range established in my digital crossovers. As I only need one extra for the centre channel and my front F/C/R have passive crossovers and will be receiving full range it would work fine just splitting the signal and feeding it to another DAC to run the centre.

Problem solved I think, if anyone has objections to that please let me know if I have missed something.

 

[arisholm]

So I thought I would look for an alternative mch USB->AES/EBU interface because of the high measured jitter on the DIO8. Even if it is not a problem when connected to high-quality DACs I thought at least I should check out the competition.
I found only one, but at a much higher price (890 USD): https://www.indexcom.com/store/iodigi8x/

But when I looked a bit more closely I found it has the exact same box dimensions (down to the mm), exact same location of the USB input and db-25 output, 5V DC-power input, same LED, same specifications using XMOS xCore-200 (16 core), even the picture of the breakout cables are the exact same. The logo on the front plate is different though...

Interesting......

PS: Next up in price to get quality AES/EBU outputs from my Mac, but with a lot more features, is the Merging HAPI with 8x AES/EBU in/out (but for RAVENNA, not USB, so even more flexibility). Also comes with high end (as in not cheap) 8ch A/D and D/A option cards (SINAD 116dB, SW gain switch 18dBu/24dBu with same specs). And word clock I/O to reduce jitter. Could be interesting to test?

 

[arisholm]

I am wondering if multiple UDIO-8s can be synched in the same way that multiple Okto DAC8s are said to be.

From where does the Okto derive the synch from? It has no Word Clock I/0...

 

[Chrise36]

From the description of the RME DIGIFACE mentioned in previous posts:
Low Jitter Design: < 1 ns in PLL mode, all inputs
Internal clock: 800 ps Jitter, Random Spread Spectrum
Jitter suppression of external clocks: > 30 dB (2.4 kHz)
Effective clock jitter influence on AD and DA conversion: near zero
PLL ensures zero dropout, even at more than 100 ns jitter
How does this translate regarding jitter is it the same with U DIO8?

 

[Kal Rubinson]

From where does the Okto derive the synch from? It has no Word Clock I/0...

From the AES/EBU output of the succeeding preceding Okto.

 

[chelgrian]

PS: Next up in price to get quality AES/EBU outputs from my Mac, but with a lot more features, is the Merging HAPI

You can do it more cheaply with a Metric Halo 2882 3D and an AES edge card. That will give you USB and their Ethernet based 'MHLink' although does give you a load of other features you don't need.

Metric Halo have a good reputation if it's deserved or not is another matter.

 

[arisholm]

You can do it more cheaply with a Metric Halo 2882 3D and an AES edge card. That will give you USB and their Ethernet based 'MHLink' although does give you a load of other features you don't need.

Metric Halo have a good reputation if it's deserved or not is another matter.

Thank you, I checked it out but ended up with the Merging HAPI as it has those unbeatable (almost) A/D and D/A cards as options if I will ever need them. And AES67 interface is the future I think... BTW, just got a response from dCS: Even with their well buffered and fancy PLL stuff on the inputs, they clearly recommended that for the best quality, an interface with AES/SPDIF output should receive a word clock input from the DAC for optimal SQ. Not that they needed to sell me anything extra as they proposed that the master clock output of the dCS Bartok should be connected to the word clock input of the HAPI, and that would improve jitter a great deal. Another alternative will of course be an external, dedicated clock (dCS likes those) but in my use case that has issues as well, related to the adaptation to the source sample rate.
So for me, that ruled out interfaces without word clock I/O, and external clocks. The Halo has word clock inputs too but not with the same quality A/D and D/A..

 

[arisholm]

From the AES/EBU output of the succeeding preceding Okto.

Yes, but this is exactly what dCS said was not an optimal approach, as "effects such as intersymbol interference that impact AES and SPDIF signals will not be present" with a proper word clock synch. But on the other hand, I suppose there is a difference between synchronising multiple dacs fairly well for a multichannel application and getting the jitter of a single channel to a minimum?
Audible difference? I have no clue