I have had an issue with the above setup with distorted audio. I am on the 3rd computer now trying to resolve distorted audio. All computers have plenty of resources, and likely not the issue. Current computer, my dad got was a hospital recycle machine, so he recycled it to me!
Current hardware:
OS version: Windows 10, 10.0, version 2009, build: 19045 (x64)
Hardware: CELSIUS M740, FUJITSU
BIOS: BIOS Date: 07/26/16 16:10:59 Ver: 05.0000B
CPU: GenuineIntel Intel(R) Xeon(R) CPU E5-1620 v4 @ 3.50GHz
Logical processors: 8
Processor groups: 1
Processor group size: 8
RAM: 24435 MB total
The audio is distorted when it passes through VAC, but not when speakers are selected. By looking at the VAC control panel I think I have an overflow issue, but don't know how to reduce. On a different laptop, HP with plenty of resources, when I disable firewall, seemed to help. I have gone through and allowed every app through the firewall, but does not seem to help.
I have various SDR devices being used from Airspy, Nooelec, and RTL SDR.
See attachment for pic of VAC panel
From the VAC manual:
Audio signal passed through a Virtual Cable becomes distorted.
Signal distortion (garbling, crackling, popping, static-like clicking etc.) usually occur due to buffering problems in audio applications, System Audio Engine or VAC driver itself, if buffer lengths/sizes used for audio data transfer are not enough to compensate application and/or system processing delays. In particular, this is due to non-realtime nature of Windows system, and especially its kernel.
First of all, please check if your system is suitable for real-time audio streaming. To achieve a stable streaming, all buffering times must be 1.5-2 times greater than longest internal delay. For example, if LatencyMon shows 20 ms internal system delays, you will have a stable audio streaming only with buffering lengths of 30-40 ms or greater. But it may not solve the problem because System Audio Engine usually uses 10-30 ms buffers to communicate with audio drivers. If the delays occur in kernel-mode code, it makes no sense to increase application buffers.
If the system is considered suitable, check VAC driver and Audio Repeater application stability.
If Virtual Cable is the only path between two applications (one is playing back and another is recording), try the following:
If you are using the Trial version that adds a female voice reminder, please pay attention to how this voice reminder sounds. Because it is added by VAC driver, playback side problems cannot affect it. Therefore, if you play a signal to a Virtual Cable endpoint and hear voice reminder clear but the signal becomes distorted, it means that recording side is OK but playback side has buffering problems. If both voice reminder and useful signal are distorted, it means that buffering problems occur on recording side and/or inside VAC driver.
Additionally, look to overflow/underflow counters for the particular Virtual Cable in VAC Control Panel. If overflow counter is not increasing, or is increasing rarely, but underflow counter is increasing rapidly, it means that buffering problems occur on the playback side, and vice versa. If both underflow and overflow counters are increasing rapidly, it means a total buffering problem due to CPU overload, high disk/network load, low cable timing event period, system timer problems etc.
If you still cannot eliminate cracks and/or distortions, please try deeper investigation and tuning described here.
Overflow and/or underflow counters in VAC Control Panel are increasing continuously.
Massive buffer overflows/underflows usually occur in two situations:
How do I resolve issue of distorted audio going to from Unitrunker to Trunking Recorder? Thanks in advance
EDIT: I would like to up it from 5 cables to 7 or 8 without issues also.
Current hardware:
OS version: Windows 10, 10.0, version 2009, build: 19045 (x64)
Hardware: CELSIUS M740, FUJITSU
BIOS: BIOS Date: 07/26/16 16:10:59 Ver: 05.0000B
CPU: GenuineIntel Intel(R) Xeon(R) CPU E5-1620 v4 @ 3.50GHz
Logical processors: 8
Processor groups: 1
Processor group size: 8
RAM: 24435 MB total
The audio is distorted when it passes through VAC, but not when speakers are selected. By looking at the VAC control panel I think I have an overflow issue, but don't know how to reduce. On a different laptop, HP with plenty of resources, when I disable firewall, seemed to help. I have gone through and allowed every app through the firewall, but does not seem to help.
I have various SDR devices being used from Airspy, Nooelec, and RTL SDR.
See attachment for pic of VAC panel
From the VAC manual:
Audio signal passed through a Virtual Cable becomes distorted.
Signal distortion (garbling, crackling, popping, static-like clicking etc.) usually occur due to buffering problems in audio applications, System Audio Engine or VAC driver itself, if buffer lengths/sizes used for audio data transfer are not enough to compensate application and/or system processing delays. In particular, this is due to non-realtime nature of Windows system, and especially its kernel.
First of all, please check if your system is suitable for real-time audio streaming. To achieve a stable streaming, all buffering times must be 1.5-2 times greater than longest internal delay. For example, if LatencyMon shows 20 ms internal system delays, you will have a stable audio streaming only with buffering lengths of 30-40 ms or greater. But it may not solve the problem because System Audio Engine usually uses 10-30 ms buffers to communicate with audio drivers. If the delays occur in kernel-mode code, it makes no sense to increase application buffers.
If the system is considered suitable, check VAC driver and Audio Repeater application stability.
If Virtual Cable is the only path between two applications (one is playing back and another is recording), try the following:
- Launch all applications before starting the streaming. Launching an application is a resource-intensive operation that often causes internal kernel delays.
- Check the CPU load and try to lower it if high.
- Try to stop unnecessary application activity.
- Try to decrease the number of milliseconds per interrupt parameter for the cable.
- Try to change appropriate port/miniport types, making sure that actual types (on the right of selection combo boxes) are changed. For example, change WaveRT to WavePci or WaveCyclic.
- Try to increase worker thread priority.
- Try to increase the buffering time in audio application.
- If your application uses DirectSound under Windows 5.x, check and adjust the DirectSound hardware acceleration level.
If you are using the Trial version that adds a female voice reminder, please pay attention to how this voice reminder sounds. Because it is added by VAC driver, playback side problems cannot affect it. Therefore, if you play a signal to a Virtual Cable endpoint and hear voice reminder clear but the signal becomes distorted, it means that recording side is OK but playback side has buffering problems. If both voice reminder and useful signal are distorted, it means that buffering problems occur on recording side and/or inside VAC driver.
Additionally, look to overflow/underflow counters for the particular Virtual Cable in VAC Control Panel. If overflow counter is not increasing, or is increasing rarely, but underflow counter is increasing rapidly, it means that buffering problems occur on the playback side, and vice versa. If both underflow and overflow counters are increasing rapidly, it means a total buffering problem due to CPU overload, high disk/network load, low cable timing event period, system timer problems etc.
If you still cannot eliminate cracks and/or distortions, please try deeper investigation and tuning described here.
Overflow and/or underflow counters in VAC Control Panel are increasing continuously.
Massive buffer overflows/underflows usually occur in two situations:
- VAC driver client (an application or System Audio Engine) fails to provide memory/data buffers in time (fast enough). In such case, you need to check your system's performance (CPU and memory speeds, CPU consumption, background disk/network activity etc.).
- Virtual Cable pin is used by System Audio Engine in shared mode and all System Audio Engine's client streams are paused. It is a normal situation caused by System Audio Engine's behavior because VAC cannot distinguish between buffer/data absence due to a temporary client failure or such pause processing technique.
- Packet mode is used for the stream, and VAC driver sees that its client is not processing the cyclic buffer in time. If there are no audible artifacts (clicks, pops, gaps), you can ignore these overflows/underflows. But if you need accurate data transmission, try to improve stream stability.
How do I resolve issue of distorted audio going to from Unitrunker to Trunking Recorder? Thanks in advance
EDIT: I would like to up it from 5 cables to 7 or 8 without issues also.
