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Apogee Firewire Mini-Dac: Is it just me or does...

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Posted on November 1, 2009 at 14:08:22
Nietzsche
Audiophile

Posts: 225
Location: Virginia
Joined: April 2, 2003
 …the source material processed by the computer SRC at its native sample rate sound the best with the Apogee Firewire mini-dac? In other words, my redbook/44.1kHz material sounds best with the audio midi set to 24/44.1 vs 44.1 material upsampled by the computer to 88.2, 176.4 or 192 (via a new 2.66GHz 15" MacBook Pro with ram upgrade, or via an old 1.25GHz G4 Powerbook alike). Sonically speaking, with 24/44.1 material upsampled in the computer from 88.1 to 192, the sound seems extra focused with more distinct and pinpointed images, with perhaps some enhanced detail resolution on a few songs. However, with the SRC upsampling in the Mac, the sound seems to be clearly lacking in many other areas, in lacking harmonic textures on voices, top end extension, particularly heard on cymbal shimmers and bells, and generally is not easy to listen to for extended periods. That said, I often question the added focus on upsampled redbook as an artifact created by the processing and not native to the disk. I’ve heard this change in sound before with dacs that can switch from 44.1 to 96 or 192 (Various very nice Cary CDPs, top end Musical Fidelity dacs and even a mediocre Philips SACD player I’ve all owned had the selectable sample rate feature), and I tended to prefer the native resolution on all of them, so maybe it’s more my ears/brain then anything?

Following suite, the native 24/96 and 24/176 music files I have sound just phenomenal with the midi set to output at their native format (24/96 or 24/176, respectively), and this sound is a clear high-rez improvement over their RBCD counterpart. As an aside, the USB minidac sounds great at 24/44.1 with 16/44.1 material, but wretched at 48kHz (its max rate) on the same, so it seems the native sample rate is the way to go to me with the Apogee dac in many regards.

I’m curious as to what MIDI sampling rate are you guys/gals with the firewire version using and why? Anyone know if the Apogee dac upsamples a 44.1 input signal and to what rate if so?


I've also noticed that uncompressed AIFF files sound slightly better then apple lossless files, either at native or upsampled resolutions, with redbook materials on the Firewire dac. I interestingly did not hear this difference with the Apogee Mini-Dac USB, where lossless was no different from AIFF or WAV's. I’m now going back and reverting my favorite and better-recorded music to AIFF, leaving mediocre recordings and rarely played music in lossless format.

Also, I’ve noticed where my newfangled MacBook Pro sounded strikingly better then the G4 Powerbook feeding the USB Apogee mini-dac, however, I'll be darned if I could tell the 2 laptops apart using the Firewire interface! Very interesting…

Lastly, as may be of interest to some, one of the Apogee dacs has a reversion "A5" board, the other is listed as "rev B." While the board and outlays look essentially identical, my eye spies a few small changes in components, in cap brands, chip labels, etc. Anyone savvy to the different versions of this dac and what exactly was changed?

I’ve only been listening to the Firewire version for the past 2 weeks (I have had the USB Mini-Dac for ~3 years), and my take on the sound could change with time, though I am really liking what I hear from this "dead" data transmission scheme!
RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 2, 2009 at 04:49:19
dgad
Audiophile

Posts: 115
Joined: July 27, 2002
 Ramallo,

Do you use external software for SRC or do you let iTunes handle it?

RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 2, 2009 at 06:59:44
ramallo
Industry Professional

Posts: 225
Location: Europe, Spain (Madrid)
Joined: May 4, 2003
 Now I'm trying the Amarra Mini, but I have all my music on iTunes with a note with the sample rate, and I change manually in the Audio Midi setup.

Some times if I want to change the SR of a file, I use the Wave Editor with the Izotope's SRC

OS X SRC, posted on November 2, 2009 at 03:28:12
Bob Stern
Audiophile

Posts: 228
Location: SF Bay Area
Joined: August 28, 2001
 The quality of the SRC in OS X Core Audio is determined by 2 parameters, Quality and Complexity, each of which has a few possible values that represent different quality levels. I cannot find any documentation by Infinite Wave stating what values of these parameters were used in their tests. iTunes uses the highest level of Quality, called Max, but does NOT use the highest level of Complexity, called Mastering, because it is very CPU-intensive.

RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 2, 2009 at 00:01:48
fmak
Audiophile

Posts: 4115
Joined: June 1, 2002
 You should not do non integer upsampling.

Great attention needs to be paid to the method of upsampling and settings.

Upsampled material done well sounds much better to me. Upsampled material not done well is disappointing. RBCD is 16 bit only and you computer must also be doing bit depth extention.

RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 2, 2009 at 09:53:19
Tony Lauck
Audiophile

Posts: 3065
Location: Vermont
Joined: November 12, 2007
Contributor
  Since: February 24, 2009
 "You should not do non integer upsampling.

Does this recommendation applies to all upsamplers? Which ones have you tested? Which settings did you use?


Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 2, 2009 at 11:19:20
fmak
Audiophile

Posts: 4115
Joined: June 1, 2002
 We had a discussion a while back.

First, I have tried all the software upsamplers for PCs which come with various forms of Foobar. Also SOX on cPlay. I don't like any of them.

So I tried softaware samplers, Audition, Sound Forge, Samplitude,and R8Brain. I prefer Audition 3.01 with no pre post filter.

My reference is dCS 972 and Purcell.

There seems to be always somewhat more 'brightness' going from 44.1 to 192k. With 176.4k, there no added sheen.

I have dismissed chip based asrcs as sounding different (and not v good)from one implementation to another.

What have you tried?
RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 2, 2009 at 11:53:24
Tony Lauck
Audiophile

Posts: 3065
Location: Vermont
Joined: November 12, 2007
Contributor
  Since: February 24, 2009
 I am using SoX for real-time upsampling of CDs. But I don't think it is quite as good as what I get from iZotope RX, or SoundforgePro 10 (which also uses iZotope 64 bit SRC). In the past I was pretty well convinced that upsampling to 176.4 was better than to 192. However, I am not so sure with iZotope.

Since my DAC runs at both rates I select the rate according to source material. However, this is a bit inconvenient, so it would be nice if this were not necessary to achieve the best sound quality. With some setups changing sample rates can be even more inconvenient, e.g. ones where the clock source is in the DAC itself rather than coming from the transport. That precludes any simple software method of adjusting the sample rate by the player.

Another SRC that I haven't tried is Weiss Saracon.

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 3, 2009 at 11:20:15
fmak
Audiophile

Posts: 4115
Joined: June 1, 2002
 I'd a look at the various iZotope settings in Sound Forge 10.

Like most audio suites, there are sliders that set upsampling quality and various settings on digital filtering. But there are no quantitative statements or graphs of what they actually do.

I think that this is one of issues when users prefer this or that package.

It's a general problem with modern non scientific software and hardware. I like to know what precisely a setting does. At least dCS pro equipment (no more) have manuals that tell exactly what is being done to the signal.

RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 3, 2009 at 12:34:40
Tony Lauck
Audiophile

Posts: 3065
Location: Vermont
Joined: November 12, 2007
Contributor
  Since: February 24, 2009
 In this case, I have some info, since the same algorithm is used in iZotope RX Advanced, where the sliders are clearly labeled with plots of various performance functions. Of course, it is always possible to test the various functions directly by generating test signals with an editor and looking at the results. The plots on the SRC comparison web site appear to be generated by the spectrum vs. time plots that iZotope RX provides.


Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 1, 2009 at 22:22:02
AbeCollins
Audiophile

Posts: 11779
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
 I've been very pleased with my Apogee Mini-DAC Firewire. I usually run mine native 24/44.1 or 24/96 for my handful of higher resolution uncompressed AIFF files. Otherwise, I'm running mostly Apple Lossless.

I've always had the Firewire version of the DAC. I recently read that the USB version has been discontinued.

RE: Apogee Firewire Mini-Dac: Is it just me or does..., posted on November 1, 2009 at 15:46:38
ramallo
Industry Professional

Posts: 225
Location: Europe, Spain (Madrid)
Joined: May 4, 2003
 (For me) The Firewire version sounds better than the USB (Drivers maybe?). But in other had, probably Apple have one of the very bes SRC in the market, look:

http://src.infinitewave.ca/

I change the sample rate every time that I play a different sampling rate file

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