MDAC first listen (part IV)

[liszt]

You appear to be living in audiophile cloud-cuckoo land.

If -30dB of digital attenuation is causing "a thin and sterile sound" or, indeed, any other substantive and repeatable "problem" with the sound quality, you are experiencing the effect of other issues.

Are you aware of just how far down in the dirt the data below bit 20 actually represents? When you are listening quietly enough to feel that things are bass-light, it's quite probable that 8 bit audio would be quite sufficient*.

And if you are listening at low enough a level to be worried by a lack of bass, you need some bass boost from somewhere - it has nothing whatsoever to do with attenuation, digital or analogue.

* The range between threshold of audibility and instant hearing damage is about 90dB. 20 bits allow for a dynamic range at least 10dB more than that, 8 bits give you 50dB, give or take.

You can make a point without being obnoxious.

I know what my ears hear. So did many people in this thread, who experienced some sound degradation due to excess digital attenuation.

The fatal flaw in your assumption is that everything else in the signal
chain behaves perfectly. Which has never been the case.

 

[janerik]

Hi Jan,

Try leaving your unit powered up for say 1 minute - dos the display eventually come up with "Comms Error"?

You could also try re-powering the unit in quick succession.

Where are you located?

John

Hi John, thanks for the quick reply.

From your first sugestion, I've now got "Audiolab no comms".

Now what??

(I'm in Montreal)

Thanks

Jan

 

[travelfotografe]

Hi John,

For serious listening sessions, I find myself listening at -30dB for "loud/compressed" commercial music/song recordings, -30dB to -24dB for better commercial recordings, and as high as -18dB for audiophile/classical recordings.

For background music, it will be between -30dB to -40dB, but since it is background, I am not too concerned.

If you still recommend -10dB attenuators, and since I am on the order list for the M-PAX, should I not just wait for the M-PAX and use its built-in attenuators?

BTW, my power amp is a Rotel RB-1582 with input sensitivity/impedance/gain rated at 1.9V/12kOhms/26.5dB into B&W 804D rated at 90dB spl (2.83V, 1m)

Thanks for your replies,
Leon

Doe you do much listening at -30dB or is it just background music levels?

If its your normal listening level, you could try the rothwell's - I suggest inserting the attenuators at the Amplifier end of the cable.

John

 

[Plutox]

I know what my ears hear. So did many people in this thread, who experienced some sound degradation due to excess digital attenuation

30dB is not excessive digital attenuation, particularly if that is what is required to achieve a low, night time listening level (which was the original enquiry way back).

volume is about -30db for nighttime listening to -20db for daytime listening

If -30dB / -40dB still results in a level that blows your head off, there is a case for analogue attenuation. But if that amount of attenuation achieves a "night time" level then any degradation due to the action of the attenuator will be so far below the threshold of hearing as not to matter.

Obviously I have no idea what constitutes your interpretation of "night time" level but for most people this is probably 60 to 70dBa. It is quite likely that a sound level of this order will give the impression of bass lightness due to the nature of human hearing as indicated by the equal loudness curves but the effect is not related to the operation of the digital attenuator itself - it's merely the result of listening quietly.

 

[JohnW]

Hi John, thanks for the quick reply.

From your first sugestion, I've now got "Audiolab no comms".

Now what??

(I'm in Montreal)

Thanks

Jan

Hi Jan,

Appears your unit has lost its software (which is the second unit this has happened too).

Hoping you have a PC to hand (better if its running Windows XP)?, if you do can you PM your Email address and a contact phone number, and I'll Email you the files,then I can call you and talk you though the process to re install the software.

John

 

[elnero]

Hi Jan,

Appears your unit has lost its software (which is the second unit this has happened too).

Hoping you have a PC to hand (better if its running Windows XP)?, if you do can you PM your Email address and a contact phone number, and I'll Email you the files,then I can call you and talk you though the process to re install the software.

John

Make that 3, a friend/co-worker bought one that had that problem as well. I believe he sent his back to the distributor. Any idea why this is happening?

 

[janerik]

Hi Jan,

Appears your unit has lost its software (which is the second unit this has happened too).

Hoping you have a PC to hand (better if its running Windows XP)?, if you do can you PM your Email address and a contact phone number, and I'll Email you the files,then I can call you and talk you though the process to re install the software.

John

Hi John

Your inbox is full, so :

janerik at bell dot net

I have Win XP

Fingers crossed

Jan

 

[Leprish]

The fix is nothing to do with sample rate. You will leave it connected to the same input for all music from the mac mini whatever its sample rate

The fix is to do with how easily/rapidly/readily the dac will relock/track variations within a single clock rate - the problems people have been reporting with tvs, digiboxes etc

In any case you'd probably be best using the usb input with the mac mini

The problem I speak of is specific to a sampling rate of 88.2KHz and was discussed in an earlier part of this thread. It was John, not me, who indicated that the problem would be addressed via the firmware update.

Re the use of USB. This isn't possible because of a bug that Apple apparently introduced when they updated the firmware last October for the mid 2011 Mac mini and MacBook Air. Again, it was John and Dominic, not me, who indicated the problem with computer USB. Dominic even submitted a post describing what was happening with USB. With this info in hand I was able to convince Apple to swap out the logic board on the Mac mini. Sadly it had absolutely no effect on either the optical or USB input problems.

With above two issues taken together I have limited options available to me for high res playback. To be frank, I'm not happy, but there doesn't seem a lot that I can do until (a) I hear what impact the firmware update has on optical port, and (b) await Apple fixing a USB port bug they seem not to be aware of.

 

[McKMini]

Got a pleasant phone call today to say I should have my hands on an M-DAC this time next week! Yeah.

 

[EIffel]

Lucky you as I'm waiting since mid December for my M-DAC to be replaced (output relay failure after just a few days, or so it seems), and was told yesterday by my reseller that I may get a new unit in March... :-(

 

[JohnW]

The problem I speak of is specific to a sampling rate of 88.2KHz and was discussed in an earlier part of this thread. It was John, not me, who indicated that the problem would be addressed via the firmware update.

Re the use of USB. This isn't possible because of a bug that Apple apparently introduced when they updated the firmware last October for the mid 2011 Mac mini and MacBook Air. Again, it was John and Dominic, not me, who indicated the problem with computer USB. Dominic even submitted a post describing what was happening with USB. With this info in hand I was able to convince Apple to swap out the logic board on the Mac mini. Sadly it had absolutely no effect on either the optical or USB input problems.

With above two issues taken together I have limited options available to me for high res playback. To be frank, I'm not happy, but there doesn't seem a lot that I can do until (a) I hear what impact the firmware update has on optical port, and (b) await Apple fixing a USB port bug they seem not to be aware of.

For your MAC USB issue you could try connecting via a USB2.0 hub, I suspect this will solve your issue.

John

 

[JohnW]

Lucky you as I'm waiting since mid December for my M-DAC to be replaced (output relay failure after just a few days, or so it seems), and was told yesterday by my reseller that I may get a new unit in March... :-(

Are you still using your MDAC, or did you send it back?

John

 

[Leprish]

For your MAC USB issue you could try connecting via a USB2.0 hub, I suspect this will solve your issue.

John

Sadly, it doesn't. I've tried both powered and unpowered USB 2.0 hubs from various vendors, none help. Basically, after a few minutes use the crackles and pops begin and get steadily worse. Strangely, this only occurs with hi res material (i.e. 88.2 KHz and 96KHz).

 

[EIffel]

John,

I've been MDAC-less since mid-December. Fortunately, I can use my Theta DSPro IIIa while waiting.

I just hope that the replacement MDAC will arrive before the MPAX...

 

[mark.king]

How does the mdac lose its software? When the new sw comes out can we have instructions on how to recover a unit when it does this please. I don't change equipment that often and often have hi fi for 10 years. I would hate to lose the software just after the gaurentee runs out or even a fe years after. Thanks

 

[JohnW]

How does the mdac lose its software? When the new sw comes out can we have instructions on how to recover a unit when it does this please. I don't change equipment that often and often have hi fi for 10 years. I would hate to lose the software just after the gaurentee runs out or even a fe years after. Thanks

Only one unit so far has been confirm to have lost its software, Jan's unit appears to be a different issue.

Only by freezing below -20Deg C can the software be lost... however it can be restored by the user with the soon to be released upgrade software package.

ATM we are at a loss to explain the single confirm case of software loss, but we are keeping an eye on the issue - however any future cases can be restored with the pending software update by the owner.

There is one possible scenario that we can imagine (however unlikely)- and it will be removed in the pending software update.

A very early beta release will be ready at the end of this week to help us diagnose the locking issues with DTV / Cable etc. If the locking issue is resolved (as we believe it well be), then we can release a "proper" build.

 

[JohnW]

John,

I've been MDAC-less since mid-December. Fortunately, I can use my Theta DSPro IIIa while waiting.

I just hope that the replacement MDAC will arrive before the MPAX...

Where are you based?

 

[JohnW]

The problem I speak of is specific to a sampling rate of 88.2KHz and was discussed in an earlier part of this thread. It was John, not me, who indicated that the problem would be addressed via the firmware update.

Re the use of USB. This isn't possible because of a bug that Apple apparently introduced when they updated the firmware last October for the mid 2011 Mac mini and MacBook Air. Again, it was John and Dominic, not me, who indicated the problem with computer USB. Dominic even submitted a post describing what was happening with USB. With this info in hand I was able to convince Apple to swap out the logic board on the Mac mini. Sadly it had absolutely no effect on either the optical or USB input problems.

With above two issues taken together I have limited options available to me for high res playback. To be frank, I'm not happy, but there doesn't seem a lot that I can do until (a) I hear what impact the firmware update has on optical port, and (b) await Apple fixing a USB port bug they seem not to be aware of.

The pending software release will indicate incomplete USB transmission packets IF this is the issue with your Apple.

 

[arthur]

Ok all. I have conceded defeat in the mighty world-wide search for four resistor xlr attenuators.

It seems they are a non breed, not simply extinct. Even the pro side came up limp.

Why do my damned Adams have such a whopping gain???

Any one know the gain on a pair of Unity Rocks? I've been meaning to try them anyway, though I do wish I could afford the Boulder. Looks a mega beast.

 

[JohnW]

Ok all. I have conceded defeat in the mighty world-wide search for four resistor xlr attenuators.

It seems they are a non breed, not simply extinct. Even the pro side came up limp.

Why do my damned Adams have such a whopping gain???

Any one know the gain on a pair of Unity Rocks? I've been meaning to try them anyway, though I do wish I could afford the Boulder. Looks a mega beast.

Arthur,

I've got your attenuators - how much attenuation do you want?

John