(rehash) Choppy audio in SDR# w/ Airspy

[batdude]

yes, I have reviewed all of the older threads... just curious if I have missed anything.

Dell Optiplex i5/8gb/256gb SDD
Windows 10 home 64bit - fresh installation - BIOS drivers up to date, no "flags" in Device Manager
integrated dell audio
USB 3.0 add in card w/ proper drivers

I am experiencing the usual "SDR# with an Airspy @ 10mbps sampling causes choppy audio"

I consider myself a fairly adept user of SDR# - and nothing seems to change the choppy audio other than lowering the sample rate to 2.5mbps - I am not convinced this is some kind of audio setting in SDR#....

I've tried both the USB 3.0 card and the integrated USB ports - no change @ 10mbps sampling = choppy, 2.5= fine

I am thinking this is some kind of USB problem - but damned if I can figure it out.

I did run the USB latency using the DPC check program - no issues noted, all way down low.

any ideas?

 

[boatbod]

10msps is a lot of data to be pushing all at once. I suspect you are hitting a bottleneck - either cpu or some firmware/driver issue with the USB infrastructure. What does you cpu utilization look like when running at 10msps vs 2.5msps?

 

[batdude]

23% CPU / 24% memory at 2.5 Mbps / 27% CPU 24% memory at 10 Mbps

 

[boatbod]

23% CPU / 24% memory at 2.5 Mbps / 27% CPU 24% memory at 10 Mbps

Probably a bus bottleneck. Have you tried different USB port to see if it makes any difference?

 

[wgbecks]

I regularly use the Airspy R2's with op25 running on Raspberry Pi3B+'s and 4B's as well as on Ubuntu VM's without issue at the 10 Mbps sample rate. The same is true when using the Airspy devices on a similarly equipped Windows PC with the only difference being is that mine runs on Windows-10 Professional 64 as opposed to your Home Edition. But I hardly believe this has any thing to do with the apparent bottleneck.

It's almost got to be a hardware issue as boatbod pointed out. You might try looking around for alternate drivers to try. It might also be worthwhile to explore configuration options for your USB3.0 add-in card. Try changing up interrupts, I/O addresses or DMA channels if the card uses DMA data transfers on the off chance that one or more of these resources are being shared with some other hardware operations.

Have you tested the Airspy on another computer, have you verified the firmware at the most current release? Do you have access to another Airspy to test with this computer to make a comparison?

Bill

 

[slicerwizard]

23% CPU / 24% memory at 2.5 Mbps / 27% CPU 24% memory at 10 Mbps

27%?

i5 has four hyperthreads and you've maxed one out. Choppy audio guaranteed.

 

[batdude]

I regularly use the Airspy R2's with op25 running on Raspberry Pi3B+'s and 4B's as well as on Ubuntu VM's without issue at the 10 Mbps sample rate. The same is true when using the Airspy devices on a similarly equipped Windows PC with the only difference being is that mine runs on Windows-10 Professional 64 as opposed to your Home Edition. But I hardly believe this has any thing to do with the apparent bottleneck.

It's almost got to be a hardware issue as boatbod pointed out. You might try looking around for alternate drivers to try. It might also be worthwhile to explore configuration options for your USB3.0 add-in card. Try changing up interrupts, I/O addresses or DMA channels if the card uses DMA data transfers on the off chance that one or more of these resources are being shared with some other hardware operations.

Have you tested the Airspy on another computer, have you verified the firmware at the most current release? Do you have access to another Airspy to test with this computer to make a comparison?

Bill

so for an experiment, i brought home a somewhat newer i7/8gb/SSD dell box. same SSD w/ bare bones installation.

(for the record, my 2 airspy's run just fine on my i7 Dell Inspiron 5440 - no issues w/ the devices at all - so problem is not the airspy hardware)

Anyway, back to the new dell box.

still has **** audio in SDR#. For SlicerWizard - i think my CPU figures are crap because of when I pulled up task manager to check them. the current i7 box is running about 2% CPU. As stated, it's a 2.8ghz i7.

couple things I noticed - right off the bat.

The desktop box is running v1803 windows 10 - it's currently sitting here churning away on the 1903 upgrade.

the laptop USB driver for the Airspy is reporting as "LibWdi" - and the desk top box is reporting the standard windows driver. I believe this is changed with Zadig - i will change it to the same driver as the laptop when the 1903 upgrade is complete and update the thread.


thanks for the help -


doug

 

[batdude]

as painful as it is - no headway. No USB 3.0 ports on this dell micro form factor pc - and no expansion slot either. I'm only seeing in the high 8msps on the airspy_rx USB monitor... so it looks like full 10msps is out of the question on this box. amazing that a freaking i7 can't manage enuf throughput based on the USB bottleneck. i've searched all over for an updated chipset driver...to see if I can increase the flow a bit... no luck. open to ideas, but I think I am hardware constrained.