SMCWAA-G - bit perfect? My mixed results.
I'm certain someone with a working knowledge of audio recording and editing software can suggest a much simpler way of doing this. If so, please suggest away.
I modified one of these SMC units to get spdif coax. I always wondered about bit-perfect output. It took a while, but I think I have proved it.
I created a wav test file of a 100Hz sine wave. A low frequency signal has more discrete amplitude values. I found this software called Mini Digital Signal Generator that can output sine and square wav files of various bit and sampling rate resolution. I used 16 bit 44.1kHz because I think that is the limit of the SMCWAA-G.
I use FUPPES as the UPNP software. If you don't mind the configuration process, it works great.
I connected the coax output to my Juli@ card SPDIF input. I used Sony Vegas 8.0 to record since I had it from a video cam purchase. I recorded using ASIO driver and Juli@ 3/4 ( digital input ) No DirectWire connections were necessary.
There may be a way to automatically start and stop the recording, but I could not figure it out and had to do it manually. I then used shntool to strip, trim and fix the resulting file.
For some reason, every file I recorded was inverted phase on both channels. I tried the Invert Channel recording tool in Vegas, but that did not work, so I must not understand how it works.
Eventually I decided to open the shntool optimized output file in Vegas and was able to figure out how to Invert Polarity for the entire recording. I saved this inverted file. I also did some shntool to trim, strip and fix, but the files are not exactly the same size, so the cmp function does not work.
I opened both files in UltraEdit 32 which is a hex editor, and has a file compare feature. The files matched perfectly during the positive phase of the sine wave, but there is a 1 LSB error for each sample of the negative phase. I presume this happened during the Vegas Invert Polarity process?
CONCLUSION - I surmise that the SMC using FUPPES and a wav file is bit perfect.
Still open for investigation is the source of the inverted channels. Is it FUPPES, the SMC unit, Juli@, the Vegas recording process? I guess I can drive the Juli@ SPDIF input with its own SPDIF output and take FUPPES and the SMC out of the picture.
Also, where did the 1 LSB error come from? One's Complement versus Two's complement arithmetic?
Anyhow, I'm satisifed for now.
I'm certain someone with a working knowledge of audio recording and editing software can suggest a much simpler way of doing this. If so, please suggest away.
I modified one of these SMC units to get spdif coax. I always wondered about bit-perfect output. It took a while, but I think I have proved it.
I created a wav test file of a 100Hz sine wave. A low frequency signal has more discrete amplitude values. I found this software called Mini Digital Signal Generator that can output sine and square wav files of various bit and sampling rate resolution. I used 16 bit 44.1kHz because I think that is the limit of the SMCWAA-G.
I use FUPPES as the UPNP software. If you don't mind the configuration process, it works great.
I connected the coax output to my Juli@ card SPDIF input. I used Sony Vegas 8.0 to record since I had it from a video cam purchase. I recorded using ASIO driver and Juli@ 3/4 ( digital input ) No DirectWire connections were necessary.
There may be a way to automatically start and stop the recording, but I could not figure it out and had to do it manually. I then used shntool to strip, trim and fix the resulting file.
For some reason, every file I recorded was inverted phase on both channels. I tried the Invert Channel recording tool in Vegas, but that did not work, so I must not understand how it works.
Eventually I decided to open the shntool optimized output file in Vegas and was able to figure out how to Invert Polarity for the entire recording. I saved this inverted file. I also did some shntool to trim, strip and fix, but the files are not exactly the same size, so the cmp function does not work.
I opened both files in UltraEdit 32 which is a hex editor, and has a file compare feature. The files matched perfectly during the positive phase of the sine wave, but there is a 1 LSB error for each sample of the negative phase. I presume this happened during the Vegas Invert Polarity process?
CONCLUSION - I surmise that the SMC using FUPPES and a wav file is bit perfect.
Still open for investigation is the source of the inverted channels. Is it FUPPES, the SMC unit, Juli@, the Vegas recording process? I guess I can drive the Juli@ SPDIF input with its own SPDIF output and take FUPPES and the SMC out of the picture.
Also, where did the 1 LSB error come from? One's Complement versus Two's complement arithmetic?
Anyhow, I'm satisifed for now.
When first saw the squeezebox and its variants I thought it would be great but $400 for the remote version was too much. I wanted a NAS for all my entire collection encoded music further driving the price and complexity.
Instead I used Media Monkey on Windows for my music server. I encoded all my CDs to FLAC for archive using EAC Exact Audio Copy for a high quality archive. This process took me a couple months but it was a very worthwhile project in every respect. I ran a 40 foot digital cable from the SPDIF PC out straight to my homemade Cirrus Logic DAC.
Next I purchased a $6 copy of iMonkey from Melloware that interfaces the iphone to Media Monkey via wifi.
I can control my entire CD collection on my Iphone right to my DAC.
I am sure there are some downsides using a PC as a source and a long digital cable but I can tell you I am as happy as a clam and it only cost me about $10 USD. I am finding the sound to be great and you can see the album info in your hand.
Just a thought, comments welcome.
Instead I used Media Monkey on Windows for my music server. I encoded all my CDs to FLAC for archive using EAC Exact Audio Copy for a high quality archive. This process took me a couple months but it was a very worthwhile project in every respect. I ran a 40 foot digital cable from the SPDIF PC out straight to my homemade Cirrus Logic DAC.
Next I purchased a $6 copy of iMonkey from Melloware that interfaces the iphone to Media Monkey via wifi.
I can control my entire CD collection on my Iphone right to my DAC.
I am sure there are some downsides using a PC as a source and a long digital cable but I can tell you I am as happy as a clam and it only cost me about $10 USD. I am finding the sound to be great and you can see the album info in your hand.
Just a thought, comments welcome.
Astone Media Gear AP-360T 1080p Media Player with PVR & HDTV Tuner
Could this be a decent alternative to a squeezebox ?
Astone Media Gear AP-360T 1080p Media Player with PVR & HDTV Tuner - Astone - Design for Life!
Could this be a decent alternative to a squeezebox ?
Astone Media Gear AP-360T 1080p Media Player with PVR & HDTV Tuner - Astone - Design for Life!
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.