Apogee DUET + iTunes, advise about setting sample rate

[Derro]

Hi all.

 

Hope someone can throw some light on this for me. Firstly, I am TOTALLY new to computer audio and digitally illiterate!

 

I am using the DUET with iTunes and a MacBook. It is ONLY for audio playback within a hi-end audiophile audio system. All my cd's have been ripped into iTunes in AIFF.

 

Now this is what I am confused...... there is talk of AudioMidi, Core Audo, Quicktime, iTunes, Maestro ....... and what sample rate should be set where. I only have this set up since yesterday, but my impressions are that using 44/16 the top end is somewhat sterile.... if I change things to 96k in AudioMidi then the top end is a little lifeless. I was under the impression, be it right or wrong that setting to 96k would mean that the original 44/16 would be upsampled to 96/24 and that playback would be enhanced. But listening does not agree with this.

 

Is there anyone out there using the DUET in a similar situation as I am and I am sure that thre are many... if so how have you got everything set?

 

Hope that someone can shed some light on this for me.

 

Thanks in advance to anyone whomay care to help.

 

DerrO

 

[The Computer Audiophile]

Hi DerrO - In your specific situation I suggest setting the rate at 16/44.1 because your source material is at 16/44.1. The only time I use upsampling is when it is done by an external DAC. When you change the Audio Midi resolution make sure you close and reopen iTunes because iTunes locks in the resolution in use when the application is opened.

 

In addition, I don't believe the Apogee DUET supports 24/96 via USB. So, with your Mac set to out put 24/96 you are really taking a 16/44.1 signal then upsampling to 24/96 then sending it to the DAC where is downsamples to 1 6/44.1. If the DUET does any upsampling itself there is a change the music is being upsampled once again. Doesn't sound good to me.

 

As far as getting better sound goes, did you rip with error correction enabled? Do you have the equalizer off? Are you normalizing the volume (hopefully not)?

 

[Derro]

Hi Chris,

 

Thanks for the prompt relpy.

 

Firstly the DUET is not USB - it is ONLY FireWire. So I do I have FireWire connection not USB. Yes, I have enabled error correction, equalizer off, volume maxed out in both iTunes and system.

 

You say Chris that you only use upsampling with an external DAC... but the Apgoee DUET IS an external DAC!

 

I have read differing opinions about setting the sample rate in AUdioMidi at 96k and forget about it then, but likewise I have also read the opposite in that I should set it to what the source is.... thats why I am a little confused. I was using the KingRex DAC prior to this but honestly I do not like it at ALL. It is bass heavy and a searing bright top end, indeed I thought that there was something amiss with my system and the Airport Express actually sounded better, much more natural.

 

The Apogee DUET is truly in another league altogether and while I was expecting an improvement, I was not prepared for the amazing sound from the DUET. Astonishing bass definition, punch and tonal qualities. A soundstage that has opened up considerably. In the past I can now say that by comparrison, it was like listening outside a venue and now with the APogee DUET I have walked through the doors and I am there!

 

Then again, it has literally only been in use since yesterday and we will see what develops after some burn-in hours.

 

I am using this in conjunction with my 300B amplifiers and Full range single drivers.

 

Thanks for your comments Chris... if you think of anything else... you might be good enough to let me know!

 

Take it Easy....

 

DerrO

 

 

 

 

[The Computer Audiophile]

Hi DerrO - Maybe I could have been a little clearer :-)

 

I did forget about the DUET being FireWire so that was an error on my part. For some reason I lumped it in there with all the USB external DACs.

 

When I said I only upsample using an external DAC I could have said I only let the external DAC do the upsampling. I don't let OS X do the upsampling.

 

I agree there are differing opinions about setting audio midi at 24/96 and just leaving it because the audible difference can be minimal, but minimal is such a subjective term. In my opinion I would take out any doubt and just set it at the resolution of your music. Then you can work on other things that may be causing the highs to not meet your needs.

 

You are surely on the right track about waiting for the burn-in period.

 

I didn't know exactly what your level of experience with all of this was and I wouldn't have recommended some of the easy stuff had I known your familiarity with it all.

 

[Derro]

>>>I only let the external DAC do the upsampling. I don't let OS X do the upsampling.

[The Computer Audiophile]

Let me clarify a bit more.

 

Let's start with a 16 bit / 44.1 kHz album that has been ripped to your hard drive.

 

1. In Audio Midi Setup set your output resolution to 44100.0 Hz / 2 ch - 16 bit. This will insure your Mac streams the album to the DAC in its native 16/44.1 resolution. This way your DAC will do the upsampling (if it does upsampling at all). This is my choice if I want to upsample.

 

2. In Audio Midi Setup set your output resolution to 96000 Hz / 2 ch - 24 bit. This will insure your Mac streams the album to the DAC only after it has been upsampled by the operating system. This is not my choice because I think a well designed external DAC will upsample better than any operating system.

 

I should still make it clear that upsampling can improve or degrade the sound depending on many different variables. The most important is the design of the DAC. There is no rule of thumb that says you should or should not upsample, it all comes down to each person's system and what they like best.

 

[baxtus]

http://www.apogeedigital.com/products/duet.php?section=support

 

[Derro]

Thanks and yes,I am aware of the Apogee link! It does not address the issue and is only an overview.

 

I mailed Apogee and the tech dept did not help and they suggested I contact Apple pose this question to Apple since in essence we're talking about software algorithms as well.

 

Thanks for the input,

 

DerrO

 

[markr]

It is possible that I do not fully understand what you are asking here, or your confusion, and I don't really have time right now to dive deeper into this ( it is beddy bye time for me ). I just have a second here, but let me suggest an exploration for you: When trying to improve the sound of a 16/44.1 computer audio file through changing the resolution of my external DAC, I have found many (most, really...) of those 'needy' 16/44.1 files sound WONDERFUL when the DAC is set to playback at 24/88.2 resolution. It is a better upsampling setting for RedBook CD quality audio files than 24/96 is.

 

Here's how:

 

With all your audio playback software closed - that's iTunes, or *any* program that can playback sound files closed/quit/NOT OPEN - simply set your Duet's Maestro software to 24/88.2 in the same way you set it to 24/96. Then set AudioMidi in the Mac's Utilities folder to the same resolution - it might already be set properly by your having set the Duet's Maestro software though. Open your playback software (iTunes?). Play the file. Let me know if you like it better. I'll try to get back to this before the weekend.....

 

Regards,

markr