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2. Re: 192kHz audio interface

Subject: 2. Re: 192kHz audio interface
From: "Max Catterwell" oatcruncher
Date: Wed Aug 5, 2009 2:48 am ((PDT))
Hi Raimund!
Very many thanks for this enlightening piece of technical commentary. It would 
appear that this is actually better than I thought it was!
I, and possibly others, would be interested to hear your opinion of what 'a 
suited recording software' might be, although I suppose that might depend upon 
the operating system.
Very best regards
Max

--- In  "Raimund Specht" <> 
wrote:
>
> Hi Max,
> 
> I have also tested this unit and can confirm that it has a very flat 
> frequency response up to 90 kHz. The frequency response of such units is 
> mainly determined by the A/D converter chips in them. The E-MU Tracker 
> employs the AK5385A chip, which is one of the best A/D chips that are 
> currently available.
> 
> http://www.emu.com/products/product.asp?product=17511&nav=technicalSpecifications
> 
> The frequency respones of the A/D chip at 192 kHz is described at page 10 of 
> its data sheet:
> 
> http://www.asahi-kasei.co.jp/akm/en/product/ak5385b/ak5385b_f00e.pdf
> 
> The relevant number here is the passband attenuation of only -0.06dB at 89 
> kHz.
> 
> This means that its frequency response at the 192 kHz sample rate is better 
> than that of the SoundDevices 7xx recorders for instance. The E-MU Tracker 
> Pre preamplifier noise level of -127dBu (unweighted) is also excellent.
> 
> So, combining the E-MU Tracker Pre with one of the cheap Netbook computers 
> (and a suited recording software) would indeed create a cost-efficient and 
> still high-quality recording system for stationary use in the field.
> 
> However, there is one detail that is a bit annoying. The firmware of the 
> E-MU-Tracker Pre does not keep the 192 kHz sample rate setting after 
> switching off the unit. So, you need to manually set the 192 kHz sample rate 
> option on its (software) Control Panel each time after booting the computer.
> 
> Regards,
> Raimund
> 
> http://www.avisoft.com
> 
> --- In  "Max Catterwell" <maxcatterwell@> 
> wrote:
> >
> > Hi Gianni,
> > I have just been looking at this piece of equipment, and have more or less 
> > decided to buy. Did you get the graphs you mentioned done yet please? I'd 
> > be very interested to see them.
> > All the best
> > Max
> > 
> > 
> > --- In  Gianni Pavan <gpavan@> wrote:
> > >
> > > Hi all,
> > > I would share some tech information about audio interfaces.
> > > 
> > > the E-MU Tracker Pre is a USB powered audio interface with 192kHz 
> > > sampling. It costs less than 150$ and offers pretty good performances.
> > > The frequency range is flat up to 90 kHz and the anti-aliasing 
> > > filtering is good. I tested it up to 200 kHz at full level and it 
> > > produces aliased components  for input signals in the range 96 to 105 
> > > kHz; resulting aliases lie in the range 96 to 87 kHz. Graphs will be 
> > > shown soon on our website.
> > > This interface has only analog I/O. At max gain the mic inputs accept 
> > > levels up to 18mVpp (measured between pins 2 and 3 of the XLR input).
> > > By comparison, the Edirol UA 25 EX has greater gain: at full gain 
> > > (knobs fully turned clockwise) it overloads with input level greater 
> > > than 10mV.
> > > 
> > > Gianni
>








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