An evening spent fiddling with my wife…

Fnaarrrr!!!! The double entendre is deliberate

I played around for a bit this evening then lined up my patient wife to listen to some Oscar Peterson about twenty times in different configurations.

I was inspired to try Integer Mode in Audirvana. To date, trying Integer mode has resulted in audible clicking from the speakers, which I understand to be a known issue caused by something in OsX testing the USB bus for certain USB chipsets. Theoretically, it offers an audible benefit and so I was keen to try.

My current CA front end is a white MacBook of mid-2009 era, with 2Gb of RAM, a 60Gb solid state hard drive and Snow Leopard installed as well as Audirvana, Pure Music and Decibel; I currently prefer Audirvana. Ripped CDs are in Apples Lossless and stored on an external Firewire drive, which is actually a cradle into which you can insert any ‘nude’ 2.5” or 3.5” SATA hard drive, and which offers USB, firewire 400 and 800, and eSATA connections. Amazon cost was under £60 and I had a spare hard drive, so it worked out very cost effective!

The USB chipset in this is older and I believe the cause of the clicking.

I also have another MacBook Pro I bought in 2011, which has 8Gb of RAM, a 3GHz CPU and a 1Tb hard drive, albeit not solid state. It is much newer with different USB chips in it, so I thought I’d try swapping this in for the white MacBook and seeing if Integer mode again resulted in clicks.

It didn’t.

Encouraged, I called my wife in and spent a good half an hour flipping back and forth between white MacBook and silver MacBook Pro, shutting each down in between to enable me to reconnect the external Firewire drive and plug in the Wireworld USB cable that routes into the Audiophilleo/DacMagic downstream.

Not ideal – over time I got the changeover to under a minute, but probably not quick enough.

Quick rewind; prior to this I reconfirmed my own findings and those of a fellow GA who stayed over a few weeks ago, and used the Arcam Alpha 5 CD player as transport playing the same Oscar Peterson 'We Get Requests' CD as was ripped on the MacBook, and got my wife to listen to both and express a preference.

She liked the MacBook (not knowing which was which) saying it was clearer and more spacious. Nice to have that reconfirmed!

When it came to comparing white MacBook with silver MacBook pro, the answer was not so clear cut. Both were set to memory play, but the Pro had 6Gb of allocated memory and the MacBook just 1Gb (both more than enough to replay a CD rip of course). The Pro had a faster CPU and was in Integer mode, with no audible clicking. The MacBook had an SSD.

I couldn’t decide between them, although after the sixth or seventh switch-over I began to detect a small improvement in articulation of piano strikes and double-bass plucks in the Pro. Alas, well within the realms of expectation bias and not conclusive. Could Integer Mode and more memory/CPU outweigh the benefits of an SSD?

My wife preferred the white MacBook. She said she 'felt it inside' more; the silver MacBook Pro was clearer, but the white MacBook nicer to listen to. On reflection, I think I see what she meant.

So, seeing as she was still game for more investigation, I tried another experiment, and set up a comparison between Audiophilleo configurations – no upsampling (as I normally have it) and full upsampling to 96KHz, which is the maximum supported by the DacMagic, although the Audiophilleo will go further.

We switched back and forth once again between the two configurations on the white MacBook, and both ended up preferring the Audiophilleo upsampling mechanism, a finding which contradicts what I’ve previously concluded.

The DacMagic upsamples internally to 192KHz even if its maximum input rate is 96KHz, using an algorithm and chipset from a Swiss company called Anagram technologies (not quite sure, but I think wholly owned by Cambridge Audio now). Therefore, if you feed it either the 44.1KHz standard CD signal or one that is separately upsampled to 96KHz, internally it is upsampled to 192KHz before decoding.

In previous tests I'd preferred to let the DacMagic handle the 44.1KHz data stream. I had assumed that the lower 44.1KHz rate would be better because it might result in less jitter over USB, and because the Anagram chipset would be better than the iZotope algorithm used by Audirvana. 

Apparently not, although the effect may be subtle.

My wife decided the Audirvana upsampling (noting she referred to it as “B” where 44.1KHz was “A”; she was listening blind) was more open and better defined; the DacMagic native upsampling was harder and more metallic, although still very good.

Personally, I felt there was greater articulation and a more rich tonality with the Audirvana algorithm – just. I heard the strike of fingers on piano keys with more definition and yet they hung together better in the entire piece. What worried me was the possibility that it might be technically more correct, but end up musically less satisfying in the long run, a common problem.

Here’s the rub – if you change something, it may shift the balance of your system and it takes time to recalibrate. Sometimes a more compressed, closed-in and ill-defined sound is more accessible and more enjoyable. A harder-hitting and thumpy sound can be more fun. So I’m going to stick with this configuration for a few days and switch back again.

Especially since, in a startling, frustrating and  yet pleasing twist, I just randomly switched Integer mode back on again on the white MacBook and…. No clicks. Not one. Nada. Plus, it DOES sound better, with yet more dynamic tension and a more natural presentation that is at once more defined and more musical and enjoyable.

Why? Why now? It could be the clicks infest 44.1 only and not after 96KHz upsampling. I will find out later, but for now I’m enjoying a glass of wine and some Phantom Limb….