Topic: Archos Gmini 120

[Brian Skalinder]

Jason - a few things:

[1]  Do the EAC WAV compare, anyway.  I encountered some apparent visual differences between my two recording sources (though not as extreme as yours), but the WAV compare showed they were bit perfect.

[2]  Assuming you're using the AES1 output, confirm your AES/EBU output from the V3 is set to a consumer signal, not pro.  

[3]  Try repeating the test but switching the outputs, i.e. V3 AES1 > impedance converter > Gmini and V3 S/PDIF coax > WT2496 > CE2K.

[JasonSobel]

thanks for the suggestions guys.  obviously, my testing isn't done yet.

Brian,
I just went to try the EAC wave compare, and it said that it wouldn't let me.  my initial 20 minute test was at 48kHz, and EAC said it would only compare 44.1kHz files.  also, a thought I just had, was to generate .md5 files for both the .wav files.  if the .wav files were exactly the same, in theory, the .md5 files should be identical.  When I did this, I got two different .md5 files   and I am using the AES1 output, and I am 100% positive that it is set to a consumer signal.


so, here's a list of the tests I will do.  at first, they will al be 20 minute tests.  if any one is successful, I'll run a longer test.

(1) run the same test, but record at 44.1 kHz

(2) Switch the outputs of the V3, so the AES goes to the Gmini, and the RCA S/PDIF goes to the WT2496.

(3) I'll record a 20minute mp3 file, and listen to it for spikes and glitches.


so, anyone have other testing suggestions?

[JasonSobel]

I've now completed the same 20 minute test, this time at 44.1kHz
I basically had the same disappointing results.  this time, I went ahead, inverted one of the files, and mixed with the other.  each spike represents a glitch.  the second image is a close up of one of the spikes.  as you can see, everything is dead-flat, 0dB, except for one misplaced sample.  at least the thing is not resampling everything.  it is bit-accurate, except for these misplaced samples.





the nest step is to run a 20-minute test, with the AES out going to the gmini, and the RCA going to the computer.  here we go...

[JasonSobel]

oh, and here's one more pic.  because test #2 was done at 44.1 kHz, I was able to run EAC .wav compare tool.  this is the result:

[JasonSobel]

so I reversed the digital outputs from the V3, and ran a 20 minute test.  This time the AES went through the impedance transformer to the Gmini, and the RCA S/PDIF went out to the Waveterminal 2496 to be recorded by Cool Edit 2000.  No luck.  same deal, with glitches ranging from a few times a minute to every few minutes.  this will be my last test of the night, maybe I can do some more this weekend, although, at this point, it doesn't look too promising.

[greenone]

Hmph. Well, that's disappointing, to say the least. Not that it matters, but are these glitches audible?

I wonder if this is something they'd consider working on for future firmware updates - I seem to remember that the JB3's bit-accuracy improved over several updates, but that could just be wishful thinking on my part.

--Dave

[Nick in Edinboro]

I wonder if this is something they'd consider working on for future firmware updates - I seem to remember that the JB3's bit-accuracy improved over several updates, but that could just be wishful thinking on my part.

I'm kinda wondering the same thing.. Also curious how it'd handle a different A/D, Jason--have you tried giving it a signal from your Waveterminal?  Not sure if it has coax out or what have you...

Maybe they can get tweak it via the firmware if we provide enough interest or something...

[timP]

wonder if it is making the spikes when the HD is saving the music? could it be a bleed over from the whir of the drive?
I have heard on iriver forums where people did similar test with it and had spikes and such every 30 seconds or so and longer evry  60 seconds...just a thought...

[JasonSobel]

spreadahead:
I've thought the same thing myself.  but the glitches seem to appear at random intervals, so I don't think that's it.
Also, have you experienced that?  I know you're going analog in, but if the glitches happen because the harddrive is writing, it shoudl probably happen regardless of whether you go analong in or digital in.

Hmph. Well, that's disappointing, to say the least. Not that it matters, but are these glitches audible?

I wonder if this is something they'd consider working on for future firmware updates

yes, they are audible, and sound like small clicks.
and it would be nice if a firmware upgrade is all that it takes.  perhaps not even a full firmware upgrade, but an upgrade to the recording plug-in?  I'm going to get in touch with their tech support and see what happens, but I know by email, it will take at least 2 or 3 days to get any response.  and I think if I'm going to try to get them to fix this and release a firmware upgrade, than I'll probably have to be in touch with someone a little higher up than the folks who have been answering my emails...

[rustoleum]

I just picked one  of these up last night and plan on doing some testing this weekend.  I've got 14 days to decide to return it so I should have some results pretty quickly.  

I'll be running my MiniMe's USB into a Vaio and the SPDIF into the 120.  I plan on starting at 16/44.1 and moving up from there.  Jason's comment about seeing the 120 lock onto a 48 khz singal from the V3 is very intriguing to me.  Great work, so far!

Keeping the fingers crossed as I'd love to have an option other than lugging a laptop from show to show.

more to come.
Rusty

[greenone]

Boy, now I feel like I should pick one up anyway just to have everyone in Massachusetts testing one (no offense, spread )...

--Dave

[JasonSobel]

This morning, I also sent an email to their tech support, with details about my testing and what I have found.  I asked them if it could be fixed with a firmware upgrade or an upgrade to their recording plug-in.  I also offered to help test any future firmware upgrades that may fix this issue.  we'll see how they respond and what happens.

Rusty, please post your results here.

I ave tried send it these signals:
16/44.1, 16/48, 16/96, 24/48, and 24/96.

it won't sync when I send it a 96 kHz signal.  with the 16/48, it says it's recording 48khz, and it plays back correctly. and with 24/48, it will lock onto the 48kHz signal, but it says that the recording bit-rate is the same as when I send a 16/48 signal, so I'm assuming that it would just truncate the 24bit data down to 16.  I haven't tested this yet, however.

[rustoleum]

For the 24 bit testing WaveLab's Bit Meter is a great way to see which bits are actually set.  You'll want to turn on the mode that lights the bits based on the amplification (intuitive mode, maybe?  can't remember and I'm at work now so I can't check).

and I will definately post my findings.

Rusty

[seethreepo]

can someone test the analog  \ line in  method of recording ,   I wouldnt mind the digital drwbacks if it takes a 16\ 48k  or 16 \ 44.1
via line in with no glitches.   also some feedback on the level meters...

thanks in advance  
& plus "t's" in spirit.  

[timP]

here isexcerpt from an IRIVER forum where a guy is doing similar testson the iriver 120, and getting the same spikes...just a little more for the mix...

1.........
In my own recording experiments, there glitches occur with mic-in and line-in.  I did not test optical.  Basically, I recorded a pure 440hz tone (sound editor generated).  Then I uploaded the WAV recording to my PC and examined it.  The glitches seem to happen when the IHP is trying to write the recorded audio to disk (every 30 seconds or so), so I presume that input type does not matter.

In my tests, the glitches show up as small clicks or as slightly distorted waveforms.  BTW, the distortions are not easy to see.

When recording to MP3 format, the disk writes occur less often (once every two or four minutes).

2.......
I did some further tone testing of the IHP-120.

With a silent line-in (very low level signal), the WAV recording was free of clicks and noise.  When the signal level approached 0db (max), the clicks appeared.  They seem to appear at 30 seconds and 90 seconds and 150 seconds and so on (plus or minus ten seconds).  

When I tried recording at 320Kbps MP3, the clicks seemed to appear less often.

When I tried the optical-in with a present but paused signal, there were no clicks, but when I input a song I did detect a click.

So it seems that the clicks/glitches are not hardware noise but are problems with processing the audio signal into a digital format.  No signal means no glitch.

BTW, a signal level that is appropriate for the NJB3 line-in input seems to overload the IHP-120 line-in input.  When testing a tone signal, it is easy to discern an overloading/clipping signal when monitoring the IHP-120.