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ITec delay at low frequency's


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#1 dduncan4@san.rr.com

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Posted 11 October 2004 - 09:15 PM

Have run a Smaart on an ITec 4000 (Amp Input to Amp Output) the delay in the low end (60 Hz) keeps moving by as much as a foot. The curve levels keep jumping up and down.

Tested Smaart on a 5002 with PIP and everything was good. Same delay every time, levels the same every time. What frequency do they run at?

Is the fact that this is a switched output device messing with Smaart? sad.gif

Why is this amp doing this?

This is not the only 4000 we have, and we have 6000's too, they do the same thing.

#2 DGlass

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Posted 12 October 2004 - 09:15 AM

I don't have an answer on that one right now but I have passed it along to be looked at. Stay tuned............... rolleyes.gif

#3 Bradford Benn

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Posted 12 October 2004 - 09:58 AM

We have used Smaart with I-Tech succesfully without the problems your are indicating. However we are not experts in Smaart and can not assist with the troubleshooting of settings within Smaart. The I-Tech family has a fixed latency.

DSP Processing: 32 bit, Floating Point, 665 ?s latency.
DAC Conversion: 24 bit, 135 ?s latency.
ADC Conversion: 18 bit, 312 ?s latency.

The amplifiers themselves switch at 250 Megahertz or 200 Megahertz depending on the model, still well outside the range of impact at 60Hz.

The first item I would recommend checking is that there is no high pass filter active on either the test microphone or the amplifier.  Also given that a 60Hz wave is about 18' 9" long the one foot variation is within 5% which may be within the range of accuracy depending on your settings.
-=Brad

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Business Development Manager - Crown International
http://www.crownaudio.com/

#4 dduncan4@san.rr.com

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Posted 12 October 2004 - 09:27 PM

This measurment was from input to output of the amp, no mics. Yes there is a high pass in the amp at 32 Hz with 18 db of slope. Will try removing it and then test again. Now dumb question why would a high pass affect delay? unsure.gif  The 5002 pip has a high pass at the same freq/slope.