Chord Electronics - Blu Mk. 2 - The Official Thread

[icebear]

Is it just me or is positioning the Blu 2 with the disc player at a maybe 30deg. angle a less than genious idea?
Common sense would indicate to position it horizontally and level it properly, this is even mentioned in some of these FM's of disc players or turntables that no one reads.

 

[DaveRedRef-III]

I have not had a problem with this. If it were a problem or even a compromise on SQ Chord would never have developed a second and third edition of the same design (Red Reference) and gone on to develop the Blu and Blu2 based upon the same design principal. The upper clam shape clamps the CD.

 

[DaveRedRef-III]

I wonder to what extent the last minute USB design amendment will have affected the launch date for Blu2 M Scaler.

 

[DaveRedRef-III]

Just been reading the perceived SQ improvements from Blu 2 M Scaler. This is from the official Chord release.

"it becomes simpler to perceive the leading edge of transient notes, creating a life-like sound-field. Bass definition is massively improved, with greater ability to follow the tune. Sound-staging, instrument separation and focus are also noticeably better, along with vastly improved variation in instrument timbre."

http://www.hifi-enthusiast.co.uk/Reviews/Chord-Electronics/Chord-Blu-MkII_21575.php

Have to say I am really looking forward to hearing that new bass definition

 

[AndrewOld]

Just noticed that the Blu2 offers switchable dither for 16 bit sources:
 
Dither:                                     On/Off (Only operational with 16bit source)
 
it says in the technical spec here: http://www.chordelectronics.co.uk/product/blu-mk-2/
 
Anyone know what kind of dither this is (e.g. TPDF), why you might want to add it, whether it is a "good thing" and whether, if it is a good thing, it could be done by other software?

 

[TheAttorney]

The dither option possibly came from romaz's impressions a while back when he was using HQ Player as the music app to drive Dave.
He reckoned that Dave sounded best with all of HQP's DSP functions switched off - apart from Dither=TPDF which he felt slightly improved the sound. A question was raised if dither added within Dave would improve SQ, and Rob replied something like: he didn't think so originally, but it's worth revisiting..
 
Subsequently, when I briefly tried a similar comparison, I agreed that Dave sounded best with all DSP off, bar Dither, which did appear to help a bit on my  redbook files. However, I felt that the Dither effect was very subtle, so not really a big deal if it was left on or off - I could achieve more obvious SQ improvements by other means.
 
It could be that Rob did subsequently find that dither could be a worthwhile option, and so incorporated it into the next product to be produced - the Blue 2. I've read that dither=TPDF is particularly good for redbook. Implying that it would not necessarily be the best option for higher bits or speeds.

 

[AndrewOld]

  The dither option possibly came from romaz's impressions a while back when he was using HQ Player as the music app to drive Dave.
He reckoned that Dave sounded best with all of HQP's DSP functions switched off - apart from Dither=TPDF which he felt slightly improved the sound. A question was raised if dither added within Dave would improve SQ, and Rob replied something like: he didn't think so originally, but it's worth revisiting..
 
Subsequently, when I briefly tried a similar comparison, I agreed that Dave sounded best with all DSP off, bar Dither, which did appear to help a bit on my  redbook files. However, I felt that the Dither effect was very subtle, so not really a big deal if it was left on or off - I could achieve more obvious SQ improvements by other means.
 
It could be that Rob did subsequently find that dither could be a worthwhile option, and so incorporated it into the next product to be produced - the Blue 2. I've read that dither=TPDF is particularly good for redbook. Implying that it would not necessarily be the best option for higher bits or speeds.

Interesting. I would have thought that if a CD had been correctly made from a higher resolution master it will already have been dithered when it was down sampled, so I can't quite understand why more dither would be beneficial. Was it on early CDs perhaps that this dithering was deemed beneficial? Obviously if you are doing digital volume control or any processing before the DAC then adding dither is correct, and players like J River will do so optionally, but otherwise should it not be done by the volume processing in DAVE? Hopefully Rob will enlighten us.

 

[514077]

 

  The dither option possibly came from romaz's impressions a while back when he was using HQ Player as the music app to drive Dave.
He reckoned that Dave sounded best with all of HQP's DSP functions switched off - apart from Dither=TPDF which he felt slightly improved the sound. A question was raised if dither added within Dave would improve SQ, and Rob replied something like: he didn't think so originally, but it's worth revisiting..
 
Subsequently, when I briefly tried a similar comparison, I agreed that Dave sounded best with all DSP off, bar Dither, which did appear to help a bit on my  redbook files. However, I felt that the Dither effect was very subtle, so not really a big deal if it was left on or off - I could achieve more obvious SQ improvements by other means.
 
It could be that Rob did subsequently find that dither could be a worthwhile option, and so incorporated it into the next product to be produced - the Blue 2. I've read that dither=TPDF is particularly good for redbook. Implying that it would not necessarily be the best option for higher bits or speeds.

Interesting. I would have thought that if a CD had been correctly made from a higher resolution master it will already have been dithered when it was down sampled, so I can't quite understand why more dither would be beneficial. Was it on early CDs perhaps that this dithering was deemed beneficial? Obviously if you are doing digital volume control or any processing before the DAC then adding dither is correct, and players like J River will do so optionally, but otherwise should it not be done by the volume processing in DAVE? Hopefully Rob will enlighten us.

I remeber from college days, we had a seminar on cd production and that dither was being added practicly in the begining; c1984.  So, is it really necessary to add it post-production at all?  In fact, converting files with FB2K, it gives you an option to add or not.  I'd like to find out the pros and cons if maybe Rob might enlighten when time permits?

 

[maxh22]

http://www.itmedia.co.jp/lifestyle/articles/1701/12/news053_2.html
 
Article on Blu MK II

 

[DaveRedRef-III]

A tempting morsel of what we can expect. Thx Maxh22

"The writer also experienced that sound, but also the depth of carving of three-dimensional sounds and the sense of air in the place where the sound source was recorded are conveyed vividly. This is a incredibly incredible performance of CDs."

 

[Rob Watts]

OK on the question of the dither switch - roll back the clock 27 years. In those days I was using PDM DAC's, which were DSD 256. These DAC's had 24 bit inputs, but I noticed that if I had 16 bit source, and so the bottom 8 bits of the 24 bits were zero, then if I simply fed random data onto the 8 zero bits, then it sounded better - smoother, with better depth and detail resolution. This was because you were improving the small signal accuracy by randomising the noise shaper.
 
But with my invention of pulse array, with noise shaping running much faster at 2048 FS and with a 5 bit output (but at the same time preserving the benefits of 1 bit), the innate resolution was orders of magnitude better; and I found that adding noise onto the zero bits had no change at all to sound quality.
 
Now on the original Blu, some customers were not using Chord DAC's; and so adding random data onto the zero data improved those DAC's.  
 
If blu 2 were a new design I would not bother with the dither switch. It is actually used for when people use other DAC's, and the benefit is that it randomises the DAC small signal performance; so DAC's that have poor small signal non-linearity have better depth and detail resolution. And the feature was kept for legacy reasons only. Note that it only functions with the CD source.
 
Now although the term dither is used, this adding of random data to zero data is not dither in the usual sense when it is applied for truncation. With truncation it is absolutely essential that the truncated bits are treated - either with dither (where the best sound is actually with Gaussian dither) or, if the sample rate allows, with advanced noise shaping. With the noise shaping I use at 16FS, I can get 64 bit resolution (THD and noise) in-band but with only 24 bit output, and this option currently sounds better than any dither scheme I have used.
 
Rob

 

[TheAttorney]

Great explanation Rob, but I still don't see how that relates to romaz hearing an improvement in DAVE when adding Dither=TPDF on HQ Player.
Or me also hearing an improvement to DAVE. Although in my case at least the effect was subtle enough that haven't discounted imagination.
I also tried Dither=Gaussian (amongst others) and didn't notice any further improvement over TPDF, so didn't bother with that as it allegedly puts a higher load on the processor.  

 

[AndrewOld]

  OK on the question of the dither switch -..
 
Rob

 
Thanks for the explanation! I guess then the Davina will not have the option of dither. 

 

[Rob Watts]

It will of course have dither for the outputs for lower sample rates; but that is just part of the process of truncation. 

 

[DaveRedRef-III]

Is there a specific date from Chord yet for the release of this product does anyone know?