Hey Paul - thanks for your filter work. I've been dragging my feet on wiring up a serial cable - didn't expect to see good (or improved) results so quickly.
OK - I was to bring it for some audition. But there will be more events 🙂
Thanks for you efforts!
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Thanks for you efforts!
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A dirty but still step-by-step instruction for your rePhase settings with a few screenshots would be nice also.
Just before you hit "output" so that one might play with it.
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Just before you hit "output" so that one might play with it.
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I am pretty puzzled here. I was able to update the firmware and upload the filter that Paul generated, all looked fine. But now when I try to connect again, the uManager is not coming up after +++. I can still see some characters when DAC power up, but whatever I type is not taking effect. I have tried three different USB to serial adapters and two different PCs, same result. Any clue?
Attachments
If you are getting the report of I and V the firmware, wiring connection and configuration should be correct.
Try turning on local echo and double check what you are sending to the DAC.
It will take me about 40x longer to document than to make the filter 🙁
Anyway I've attached and zip with screenshots and the .rephase settings file. Open that in rePhase and you see the same thing as the screenshots.
How-to? I was going off the graphs in the Ayre white paper and the description of the Listen filter as being minimal phase. I could tell from the graphs and description that the curve was -6dB at Nyquist (22050) and that it dropped to -96dB some around 40kHz.
From that information I messed around with corner frequency and curve slope under the minimum phase tab to get something that came close to fitting. The steepness of the filter slope directly effects the amount of ringing so I was aiming to keep a reasonably gentle slope while trying to avoid attenuating the audio band as far as possible. This is a trade-off.
Once I had a set of parameters that looked reasonable, for the corner frequency/slope I started looking when the filter curve crossed the -96dB mark. Rather than start rolling off the highs (which it now appears Ayre actually did) , I opted to use a linear phase filter set high enough that it didn't directly impact the audio band, but ensured that the filter was steep enough to be -100dB at the sampling frequency. Again the steeper the filter the greater the ringing so the aim was to keep the slope as gentle as was possible. It might be that shifting the corner frequency down a bit further, and reducing the slope will reduce the pre-ringing.
I was using a combination of Fuzzmeasure to analyse .wav's and a neat freeware app called ClickPlot ( https://itunes.apple.com/us/app/clickplot/id527031161?mt=12 ) to plot the impulse response from the .txt output of rePhase and to check the impulse from Søren's filter.
I'm basically having a play around to see what does what. The MixPhase1 filter (which is misnamed - it should be intermediate-phase) sounds pretty good to my ears but it can definitely be tweaked and refined.
Attachments
My experiance is that I got it working with Zterm on OS X but missed the macbinary setitng so update failed. This made me resort to my backup PC laptop and that worked. Trying to used Zterm again I just cant seem to get that working anymore. Strange. I'm dam-ed 😉 if the DAM dont change some setting / states after it has been used wich seem to stick. Something fishy is going on I suspect.
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Aha...
Fiddled around with zTerm settings and voila.. worked (excuse me for attacking DAM Sören).
I happend to send "release call" and 8-o :
dam1021 uManager Rev 0.80 20150121 FPGA Rev 0.9 Press ? for help.
# ATH0
Invalid Command.
#
# help
uManager Commands
------
I have a 3 meter extension cable with a USB/serial dongle:
Product ID: 0x6001
Vendor ID: 0x0403 (Future Technology Devices International Limited)
Version: 4.00
Serial Number: FTDXFFMH
Speed: Up to 12 Mb/sec
Manufacturer: FTDI
Location ID: 0x14200000 / 7
Current Available (mA): 500
Current Required (mA): 44
Zterm settings where:
- No Xon/Xoff
When a do exit in umanager it says:
# exit
I2
L044
V-22
and +++ gives (no local echo)
dam1021 uManager Rev 0.80 20150121 FPGA Rev 0.9 Press ? for help.
#
As it should be. Seems to be some initialization problem with something.
Fiddled around with zTerm settings and voila.. worked (excuse me for attacking DAM Sören).
I happend to send "release call" and 8-o :
dam1021 uManager Rev 0.80 20150121 FPGA Rev 0.9 Press ? for help.
# ATH0
Invalid Command.
#
# help
uManager Commands
------
I have a 3 meter extension cable with a USB/serial dongle:
Product ID: 0x6001
Vendor ID: 0x0403 (Future Technology Devices International Limited)
Version: 4.00
Serial Number: FTDXFFMH
Speed: Up to 12 Mb/sec
Manufacturer: FTDI
Location ID: 0x14200000 / 7
Current Available (mA): 500
Current Required (mA): 44
Zterm settings where:
- No Xon/Xoff
When a do exit in umanager it says:
# exit
I2
L044
V-22
and +++ gives (no local echo)
dam1021 uManager Rev 0.80 20150121 FPGA Rev 0.9 Press ? for help.
#
As it should be. Seems to be some initialization problem with something.
Seriously, on Mac, give Serial app a try: https://www.decisivetactics.com/products/serial/
I had the same ZTerm issues, not being able to connect again. Serial worked every time. I'm at the end of 7 day trial but will buy the license. It also comes bundled with drivers for various USB serial converters, which may be convenient for the particular converter you are using.
I let the board powered off overnight, first try in the morning, now works just fine. So weird.