[PlanetCCRMA] Re: HDSP9652 muted on system start

Michele Spinolo michele.spinolo@tin.it
Sun Aug 28 11:22:01 2005

Hi Gregory,

yes, I do use the same cables.
I made more tests, and I have more findings: looping output 1 with input 2
gives good results, while I have the worst results looping output 2 with
input 1.
Looking at HDSP mixer I noticed that when bad results occur the signal in
the first row of hdsp mixer starts after the signals in last 2 rows.
So I do not know if it is a software problem or not.

really strange!



You using the same cable for both loops? I got results like that when
I had a bad cable.
I now test all my cables that way.

Also, it's useful to edit the octave script to reduce the ranges.


On 8/28/05, Michele Spinolo <michele.spinolo@tin.it> wrote:
> Hi Mark,
> you pointed out some nice points, which I will go through.
> First my setup is: RME HDSP9652 connected to ADI-8 Pro via ADAT, ADI-8 Pro
> analog out to ADI-8 Pro analog input, ADI-8 Pro ADAT output to HDSP9652
> input.
> All stuff is running at 44.1Khz: RME HDSP9652 is set as master, while
> Pro as slave, getting clock signal from ADAT input.
> Now lets go through clock settings: I noticed that setting a different
> source for RME ADI-8 Pro inputs and outputs (i.e. ADAT input for analog
> outputs, while internal clock for analog inputs) gives really really bad
> results.
> I also tried to set ADI-8 Pro as master clock, connecting HDSP9652 by
> wordclock (BNC 75Ohm cable) and results where really bad (not so bad as in
> first set up described).
> The best setup I can get is using HDSP9652 as master clock and slaving
> Pro reading clock signal from ADAT input (both for ADC and DAC).
> I went through the problem posted in this thread this afternoon, and made
> new measurement: looped output 1 with input 1 and output 2 with input 2:
> http://michelespinolo.altervista.org/rme/loop0-vs-loop1.pdf
> Results are relly bad in latter case, while in the former are comparable
> with RME declared ADI-8 Pro performances.
> So the problem is releated to a different behaviour of DAC and ADC on
> channel 1 with respect to DAC and ADC on channel 2, NOT to hdspmixer
> settings.
> I find this really annoying.
> Next week I will go through the problem, measuring all loops and also
> crossing them, to understand if it is an single problem of a DAC or ADC
> section or not.
> Concerning Edward's program it a simple tool which performs these
> operations:
> -playing a logaritmic sine sweep signal while recording it (you can assing
> sample frequency, starting and ending frequency)
> -convolving the recorded logaritmic sine sweep with a inverse logaritmic
> sine sweep extracting an impulse response: this is the impulse response
> which represent your chain (in my case AD and DA conversions performed by
> ADI-8 Pro)
> That's all.
> Bye
> Michele
> P.S. Z-sys unit is actually not used: it has some design problem which I
> trying to solve with Z-sys
> P.P.S. PDF files measurements report is generated by an automatic script
> which I use to analyse speaker performances: than only fig. 1 to 13 and
> 33 to 40 are of some interest in this case. Also do not read captions
> do not describe those figures
> ________
> Hi Michele,
>    It may be because reading technical documents and looking at graphs
> is always a bit difficult at 7AM on a Sunday morning, or simply that
> I'm too dense to understand what the data is telling me, but so far
> I'm not understanding the exact problem. Maybe you can clarify that a
> bit more for me?
>    I am interested as I have an HDSP 9652 also and I've had a problem
> with it for over 3 years that the developers have never solved. I'm
> wondering if my problem and what you are seeing have anything to do
> with each other.
>    If I understand what you are doing then you have Edward's program
> generating a sine sweep, going to the HDSP 9652 which is attached to
> the ADI-8 Pro and is converted to analog. That analog input is looped
> back into the ADI-8 Pro, sent back to the HDSP 9652 and then to
> Edward's program again. Is this the setup?
>    Where is the clock master in this setup? Is it the HDSP 9652? Is it
> the ADI-8? Is it something else? (You had a Zsys, correct?)
>    The problem is that with hdspmixer closed you get some clipping,
> but the clipping only happens when you start the program and then goes
> away, while with hdspmixer open you do not see the clipping. Is this
> the case?
>    If I'm understanding both the setup and the problem correctly, then
> please do some simple experiments with hdspconf. You may actually be
> seeing a version of the problem I've had for years. With hdspmixer not
> running open hdspconf and cjeck the frequency that the HDSP 9652 is
> running at. Now run Edward's program. (You may need to run it a few
> times.) Do you see the frequency of the HDSP 9652 changing? Do you see
> the clock source of the HDSP 9652 changing? Note that you may need to
> run the test a few times to see the frequency change in hdspconf. It
> happens quickly. The indicator in hdspconf will move and then move
> back and it's not always easy to see.
>    I do see these change, and I See them change at strange times. I've
> found that things are much better when running Jack since Jack locks
> the device down to a specific frequency and Jack apps cannot change
> it. However, with OSS and Alsa apps I see the freqency change at odd
> times. It is worse with OSS emulation. These frequency changes are not
> well managed, either in Alsa or OSS, and the driver does not ensure
> that ''zero' volume data is going out the port when it changes
> frequency, so when it happens I get horrible popping/scratching sounds
> that will sometimes make me think my speakers have blown up.
>    My setup here is similar to yours, assuming that I've described it
> correctly above. If you see the same frequency changes then maybe we
> can get some attention from the developers on this issue. I've found
> it's worse using external clocks where the HDSP is being asked to sync
> a better clock.
> Cheers,
> Mark
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