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New Head-Fier
- Joined
- Jul 29, 2012
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Okay, so the device giving me trouble is the Astro A40 Mixamp, as seen here. What I'm attempting to do with it is capture audio via the headset port by attaching a 3.5mm cable from it to my Xonar STXs mic port. The eventual goal is to use a splitter to bring audio to both headset and the STXs mic in order to capture game chat+audio for video I'm capturing with my cap card from my Xbox 360.
However, currently I'm getting terrible line noise from the audio coming from the 3.5mm stereo cable to my STXs mic port. In addition to this I get the same line noise when connecting my A40s mic out port to the mic in on the STX. Needless to say this prevents any useful capture of audio.
To isolate the problem I've done a multitude of tests. I'll outline and post them at the bottom for those who desire to fully understand the situation. In addition I've uploaded some recordings to SoundCloud which I will link.
Needless to say the conclusion from all the tests are that the line noise is produced from the Mixamp, and it is not audible when listening through Headphones such as the A40s/HD555s.
I would like to know what options I have in reducing this line noise. I've read that ferrite cores can help but that they can also reduce sound quality for most all setups. This would not be much of an issue to me however, as the recorded audio would be uploaded to youtube/twitch.tv. What has me confused and uncertain is that there seem to be many different kinds of ferrite cores that prevent EMI/RFI at different frequencies and I have no clue whatsoever which thresholds I should opt for in this scenario, or any for that matter, as my technical understanding of audio is quite limited.
I attempted to locally procure some ferrite chokes on Saturday only to run out of time. I tried two music stores who sell high-end audio equipment to no avail. I then tried a close-by Radio Shack in a last ditch effort. They only had the small version of the choke which did not fit around the 3.5mm cable. I used the website to locate stores with the 5mm models in stock, called them, and they told me that they were not compatible for use with analogue stereo signals. So, here I am, uncertain of which options to consider, which parts to order, or even which line of research to pursue to begin understanding this issue.
Thanks in advance.
Note, I am using W7-64 Ultimate, which I clean installed last week for performance and as prep for installing the BMIP. I have been observing the line noise via 'monitor this device' and recording in Audacity with & w/o monitoring enabled. Also note that when using the A40 headset or my HD555s no line noise is audible from them, while it is still present via the 3.5mm->STX. For testing with the headsets I tested with a splitter so that I could hear with the headset and still output to the STX.
I first tried a second 6ft 3.5mm stereo cable. I then tried a third 8ft 3.5mm stereo cable. I then attached different 3.5mm->6.3mm adapters. I then detached the USB that normally powers the device and used some AAs for power. The last two cables rested upon my lap, while the first (10ft) is routed behind my desk to the PC.
After this I detached everything but the Toslink coming from my 360. I then detached the Toslink as well. I also happened to have a second Mixamp at hand(two sets of A40 audio systems). The problem was, iirc, more pronounced on my backup Mixamp.
In all of the above I also attempted to use the motherboards mic port. The line noise was present when utilizing it for capture as well.
I have tweaked just about every setting available in the Xonars Utility menu as well as options in Windows 7s Sound panel. Turning off the Mic Boost reduces the issue, but it is still quite noticeable. Doing so also reduces the volume of the capture a great deal. Turning off mic boost results in the mic from the A40s via it's mic out port becoming inaudible.
After all of the above I then started detaching my other USB devices and ethernet. After this I then removed the capture card(Intensity Pro - PCIe x4 interface). After this I changed the PCIe slot my Xonar STX was in. I then removed the STX and attempted once again to use the motherboards mic in slot. For reference, the motherboard is the Asus p8z68-v Gen 3, Realtek drivers are not installed. I then reassembled my PC
.
*Deep Breath*. The next step, or rather, steps I have taken in conjunction with all of the above at different times within those actions, was to test the capture of other devices through the STX. Mic boost was enabled for all of these tests. My Zalman clip-on mic which is attached to my AD700s does not have any line noise. Audio carried via the same mediabridge 3.5mm cable I've used the most throughout testing from a laptop to the STX mic port also did not present line noise. I also tried to test an mp3 player, but it was not..stable. I did receive some audio enough to hear that it also did not have line noise.
In a half-assed effort I detached all power cables from my surge protector power strip except for the PSU powering the PC.
As a result of the above steps, it is clear (to me at least) the A40 Mixamp is producing the line noise.
SoundCloud
P.S. Polz Halp
However, currently I'm getting terrible line noise from the audio coming from the 3.5mm stereo cable to my STXs mic port. In addition to this I get the same line noise when connecting my A40s mic out port to the mic in on the STX. Needless to say this prevents any useful capture of audio.
To isolate the problem I've done a multitude of tests. I'll outline and post them at the bottom for those who desire to fully understand the situation. In addition I've uploaded some recordings to SoundCloud which I will link.
Needless to say the conclusion from all the tests are that the line noise is produced from the Mixamp, and it is not audible when listening through Headphones such as the A40s/HD555s.
I would like to know what options I have in reducing this line noise. I've read that ferrite cores can help but that they can also reduce sound quality for most all setups. This would not be much of an issue to me however, as the recorded audio would be uploaded to youtube/twitch.tv. What has me confused and uncertain is that there seem to be many different kinds of ferrite cores that prevent EMI/RFI at different frequencies and I have no clue whatsoever which thresholds I should opt for in this scenario, or any for that matter, as my technical understanding of audio is quite limited.
I attempted to locally procure some ferrite chokes on Saturday only to run out of time. I tried two music stores who sell high-end audio equipment to no avail. I then tried a close-by Radio Shack in a last ditch effort. They only had the small version of the choke which did not fit around the 3.5mm cable. I used the website to locate stores with the 5mm models in stock, called them, and they told me that they were not compatible for use with analogue stereo signals. So, here I am, uncertain of which options to consider, which parts to order, or even which line of research to pursue to begin understanding this issue.
Thanks in advance.
Steps I Took to Isolate Source of Line Noise
Note, I am using W7-64 Ultimate, which I clean installed last week for performance and as prep for installing the BMIP. I have been observing the line noise via 'monitor this device' and recording in Audacity with & w/o monitoring enabled. Also note that when using the A40 headset or my HD555s no line noise is audible from them, while it is still present via the 3.5mm->STX. For testing with the headsets I tested with a splitter so that I could hear with the headset and still output to the STX.
I first tried a second 6ft 3.5mm stereo cable. I then tried a third 8ft 3.5mm stereo cable. I then attached different 3.5mm->6.3mm adapters. I then detached the USB that normally powers the device and used some AAs for power. The last two cables rested upon my lap, while the first (10ft) is routed behind my desk to the PC.
After this I detached everything but the Toslink coming from my 360. I then detached the Toslink as well. I also happened to have a second Mixamp at hand(two sets of A40 audio systems). The problem was, iirc, more pronounced on my backup Mixamp.
In all of the above I also attempted to use the motherboards mic port. The line noise was present when utilizing it for capture as well.
I have tweaked just about every setting available in the Xonars Utility menu as well as options in Windows 7s Sound panel. Turning off the Mic Boost reduces the issue, but it is still quite noticeable. Doing so also reduces the volume of the capture a great deal. Turning off mic boost results in the mic from the A40s via it's mic out port becoming inaudible.
After all of the above I then started detaching my other USB devices and ethernet. After this I then removed the capture card(Intensity Pro - PCIe x4 interface). After this I changed the PCIe slot my Xonar STX was in. I then removed the STX and attempted once again to use the motherboards mic in slot. For reference, the motherboard is the Asus p8z68-v Gen 3, Realtek drivers are not installed. I then reassembled my PC
.*Deep Breath*. The next step, or rather, steps I have taken in conjunction with all of the above at different times within those actions, was to test the capture of other devices through the STX. Mic boost was enabled for all of these tests. My Zalman clip-on mic which is attached to my AD700s does not have any line noise. Audio carried via the same mediabridge 3.5mm cable I've used the most throughout testing from a laptop to the STX mic port also did not present line noise. I also tried to test an mp3 player, but it was not..stable. I did receive some audio enough to hear that it also did not have line noise.
In a half-assed effort I detached all power cables from my surge protector power strip except for the PSU powering the PC.
As a result of the above steps, it is clear (to me at least) the A40 Mixamp is producing the line noise.
SoundCloud
P.S. Polz Halp
