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Everything sounds the same


mansr

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On 9/19/2018 at 3:03 AM, firedog said:

Recipe calls for 1 gram of salt. 
I add one gram of fine grained table salt in at the beginning of the cooking process.

Make simultaneously another batch and add one gram of kosher salt in 2 minutes before the dish is plated and served. 
In both cases the salt is dissolved. 
The two dishes don't taste the same. 
Can you figure out why? 

Because (most basically) the salt causes foods to release water.  If added at the beginning of a cook, the juices of the food will be more incorporated into the whole dish.  If added in the end, the juices will not release to the whole dish as readily and therefore  be more concentrated in each individual food piece. 

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1 hour ago, Blake said:

 

Wait a minute, I thought you were all focused on after-purchase tweaking of the insides of your equipment and other mysterious optimizations, yet all this time you have been you have never used a DAC as a stand alone component and instead are relying on the DAC in your computer?  

 

All DACs sound the same.   (cf:  thread title)

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1 minute ago, wgscott said:

 

All DACs sound the same.   (cf:  thread title)

 

Oh yeah, I forgot about that.   A DAC is a DAC is a DAC.  I think I have it now.

 

Carry on. 

Speaker Room: Lumin U1X | Lampizator Pacific 2 | Viva Linea | Constellation Inspiration Stereo 1.0 | FinkTeam Kim | Revel subs  

Office Headphone System: Lumin U1X | Lampizator Golden Gate 3 | Viva Egoista | Abyss AB1266 Phi TC 

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7 minutes ago, Blake said:

 

Oh yeah, I forgot about that.   A DAC is a DAC is a DAC.  I think I have it now.

 

Carry on. 

Does a $5 clock radio have a DAC?

Windows 11 PC, Roon, HQPlayer, Focus Fidelity convolutions, iFi Zen Stream, Paul Hynes SR4, Mutec REF10, Mutec MC3+USB, Devialet 1000Pro, KEF Blade.  Plus Pro-Ject Signature 12 TT for playing my 'legacy' vinyl collection. Desktop system; RME ADI-2 DAC fs, Meze Empyrean headphones.

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3 hours ago, Richard Dale said:

The host end in the PC doesn't control the DAC timing, it controls the timing of the rate at which frames are sent. The DAC end can control how fully populated the frames are with audio samples.

 

The samples are sent in micro packets every 125 micro-seconds. That's the clock rate that drives PC output. That is not (and cannot be) the rate that drives the DAC, otherwise you'll have a very broken analog output that sounds like an 8KHz signal. The packets are received on the DAC side, stored in a buffer, and then doled out to the D2A converter by a local clock, independent of that on the PC.

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7 minutes ago, pkane2001 said:

 

The samples are sent in micro packets every 125 micro-seconds. That's the clock rate that drives PC output. That is not (and cannot be) the rate that drives the DAC, otherwise you'll have a very broken analog output that sounds like an 8KHz signal. The packets are received on the DAC side, stored in a buffer, and then doled out to the D2A converter by a local clock, independent of that on the PC.

Yes, that sounds correct to me.

 

With respect to your original comment, I think the protocol you really want is I2S where the slave's clock can actually control the timing of the transactions with the master, rather than just the flow control like isochronous USB. But then there is no agreed cabling standard for I2S.

System (i): Stack Audio Link > 2Qute+MCRU psu; Gyrodec/SME V/Hana SL/EAT E-Glo Petit/Magnum Dynalab FT101A) > PrimaLuna Evo 100 amp > Klipsch RP-600M/REL T5x subs

System (ii): Allo USB Signature > Bel Canto uLink+AQVOX psu > Chord Hugo > APPJ EL34 > Tandy LX5/REL Tzero v3 subs

System (iii) KEF LS50W/KEF R400b subs

 

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6 minutes ago, Richard Dale said:

Yes, that sounds correct to me.

 

With respect to your original comment, I think the protocol you really want is I2S where the slave's clock can actually control the timing of the transactions with the master, rather than just the flow control like isochronous USB. But then there is no agreed cabling standard for I2S.

 

With I2S the clock at the source can drive the DAC directly. While that works well for short distance runs (like a few short traces on the PCB) it may not be appropriate for a 1m cable. If a USB cable has such major issues with noise and interference as is being claimed, despite the data being reclocked, you can only imagine how bad the noise will be if it's induced directly into the clock signal.

 

That said, I've been using I2S short run connections (0.3m) on HDMI LVDS connectors with no audible issues with my DACs. 

 

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11 minutes ago, pkane2001 said:

 

With I2S the clock at the source can drive the DAC directly.

 

My point was that although the source or master can provide the clock for the I2S transactions, it is also possible for the slave end, ie the DAC, to provide the clock.

System (i): Stack Audio Link > 2Qute+MCRU psu; Gyrodec/SME V/Hana SL/EAT E-Glo Petit/Magnum Dynalab FT101A) > PrimaLuna Evo 100 amp > Klipsch RP-600M/REL T5x subs

System (ii): Allo USB Signature > Bel Canto uLink+AQVOX psu > Chord Hugo > APPJ EL34 > Tandy LX5/REL Tzero v3 subs

System (iii) KEF LS50W/KEF R400b subs

 

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1 hour ago, Richard Dale said:

My point was that although the source or master can provide the clock for the I2S transactions, it is also possible for the slave end, ie the DAC, to provide the clock.

 

Not in the I2S protocol itself. One could develop an extension of the I2S which could be bidirectional, but that would be proprietary.

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10 minutes ago, jabbr said:

 

Not in the I2S protocol itself. One could develop an extension of the I2S which could be bidirectional, but that would be proprietary.

There are certainly Raspberry Pi I2S DACs where the DAC has the clock controlling the I2S transactions and not the source. Maybe in I2S terminology it says that whichever end is the clock is the master, and the source of the data is not always called 'master'.

System (i): Stack Audio Link > 2Qute+MCRU psu; Gyrodec/SME V/Hana SL/EAT E-Glo Petit/Magnum Dynalab FT101A) > PrimaLuna Evo 100 amp > Klipsch RP-600M/REL T5x subs

System (ii): Allo USB Signature > Bel Canto uLink+AQVOX psu > Chord Hugo > APPJ EL34 > Tandy LX5/REL Tzero v3 subs

System (iii) KEF LS50W/KEF R400b subs

 

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5 hours ago, manisandher said:

 

It is actually. I've got 10 international client workshops to deliver before the end of the year, and want to spend some time with my family too.

 

Like most people here, this is just a hobby for me. I have nothing to prove to anyone ?.

 

Mani.

 

Isn't the software processing a possible source of differences, that was not controlled for?

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2 hours ago, Richard Dale said:

Yes, that sounds correct to me.

 

With respect to your original comment, I think the protocol you really want is I2S where the slave's clock can actually control the timing of the transactions with the master, rather than just the flow control like isochronous USB. But then there is no agreed cabling standard for I2S.

Because it an interface that was NOT designed to go down cables, its a local on board bus, designed for limited distance.

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38 minutes ago, mansr said:

Most chips with I2S interfaces support both master and slave mode.

 

Are we talking about inter-chip I2S (as designed) or one of the I2S over LVDS implementations? Which DACs which have an I2S input provide a clock output? I’m curious.

Custom room treatments for headphone users.

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8 minutes ago, jabbr said:

Are we talking about inter-chip I2S (as designed) or one of the I2S over LVDS implementations? Which DACs which have an I2S input provide a clock output? I’m curious.

 

Here's a good summary from @vortecjr of Sonore:

 

Quote

... technically most DACs with i2s inputs via a RJ-45 connector accept an external master clock. Some DACs that have a LVDS i2s input via HDMI connector also accept external master clock, but most of these ignore the master clock

 

The linked document is very detailed, although I can't vouch for its accuracy. It does list where the master clock originates for most I2S devices:

 

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1 hour ago, Richard Dale said:

There are certainly Raspberry Pi I2S DACs where the DAC has the clock controlling the I2S transactions and not the source. Maybe in I2S terminology it says that whichever end is the clock is the master, and the source of the data is not always called 'master'.

I am unaware of a RPi board which itself accepts a clock input. AFAIK there are FIFO reclocking boards (mezzanine) for the RPi which accept the RPi I2S ouput, then buffer and reclock with the DAC master clock. This s is an excellent way to do it. DIYAudio @iancanada provides such boards, and I’ve used. 

Custom room treatments for headphone users.

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5 minutes ago, jabbr said:

@pkane2001 right, the DACs accept an external clock! I’m asking about DACs which have a good clock right next to the DA converter and which send this clock out to act as the master for the I2S bits coming in ... not so common

 

Right. I recall reading about one such implementation, but can't recall the DAC... or even if it was I2S or some custom connection.

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39 minutes ago, jabbr said:

Are we talking about inter-chip I2S (as designed) or one of the I2S over LVDS implementations? Which DACs which have an I2S input provide a clock output? I’m curious.

I'm talking about actual I2S, a single-ended connection between chips on a PCB. Nothing else is a standard. As for those DAC boxes with I2S-like inputs, I'm not aware of any that send the clock upstream.

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15 minutes ago, mansr said:

I'm talking about actual I2S, a single-ended connection between chips on a PCB. Nothing else is a standard. As for those DAC boxes with I2S-like inputs, I'm not aware of any that send the clock upstream.

 

Right. 

 

I’m clarifying because unfortunately “I2S” is used to describe the external LVDS between boxes. We got on this because someone suggested replacing USB with I2S and I assumed that meant the LVDS/external variant.

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34 minutes ago, jabbr said:

I am unaware of a RPi board which itself accepts a clock input. AFAIK there are FIFO reclocking boards (mezzanine) for the RPi which accept the RPi I2S ouput, then buffer and reclock with the DAC master clock. This s is an excellent way to do it. DIYAudio @iancanada provides such boards, and I’ve used. 

The HiFiBerry DAC+ Pro has its own clocks and they are used for the DAC and the I2S bus: 

https://www.hifiberry.com/shop/boards/hifiberry-dac-pro/

System (i): Stack Audio Link > 2Qute+MCRU psu; Gyrodec/SME V/Hana SL/EAT E-Glo Petit/Magnum Dynalab FT101A) > PrimaLuna Evo 100 amp > Klipsch RP-600M/REL T5x subs

System (ii): Allo USB Signature > Bel Canto uLink+AQVOX psu > Chord Hugo > APPJ EL34 > Tandy LX5/REL Tzero v3 subs

System (iii) KEF LS50W/KEF R400b subs

 

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