2873Re: [powersdr-iq] Re: PowerSDR-IQ and Ensemble II RX
- Sep 28, 2013Most of the problems with using two sound cards come from a failure to plan on having all channels running from a common clock or the software problems that result. Firewire '400' doesn't run exactly at 400 mbits a second but it does run at a multiple of 48000 Hz...specifically it runs at 8192x48KHz(393.216 MHz). It is possible to derive a common clock for all ports on firewire card, although I couldn't tell you which cards do implement that when they're "master" timing sources. USB devices running at 12 or 480 MHz have the disadvantage of not being able to share a common clock source unless you are using using an spdif clock source. For various reasons that is almost never a feasible topology. USB has the added disadvantage that the 12MHz clock tends to leak into the (usually inferior) ADC as either a DC offset or an alias at some other frequency depending on sample rate (notable exception are the TI chips that uses 250x instead of 250x division).
There are Intel HD audio codecs that also decimate by 250 instead of 256 from a base clock of 24MHz. They tend to suffer from a lack of high end ADC chips and/or high noise pickup from being on a motherboard next to very high speed clocks.
There is a reason the delta 44, FA-66 and firebox are also popular solution. They provide enough channels and just work. The creative emu-1212m would need additional channels via spdif plus mic preamp and headphone amp for a transceiver but makes has excellent ADCs. The creative emu-1820m is excellent but pricey (mine delivers something like 20.5 bits at 192KHz and 21.5 bits at 192 KHz at 48KHz). It has built in mic and headphone amps. The ADCS in the creative emu-1xxxm series are some of the best available and are even better than those in the above mentioned. For me the 1820m just worked with no special configuration required. I chose it for the 192KHz ADCs.
The USB2SDR does look like a great solution but I haven't personally used one (at the time the lack of onboard 192KHz ADCs was a deal killer for me even though there was a planned add on).
While it is theoretically possible to use two different sound cards as sources in ASIO4ALL, I wouldn't recommend it because you probably wouldn't end up there if your clock sources were well planned out. You'll also find that you can't open ASIO sources from two vendors at the same time (I tried that with my 1212m card and the built in pc sound...didn't work).
In summary, take a hard look at what you're thinking about using before you deviate from something supported or purpose built like the USB2SDR. You'll probably be money ahead in the long run and save weeks/months worth of messing around.
From: "ericwd9" <ericwd9@...>
To: "firstname.lastname@example.org" <email@example.com>
Sent: September 28, 2013 5:44 AM
Subject: [powersdr-iq] Re: PowerSDR-IQ and Ensemble II RX
I reply to your query on sound cards.
If you wish to transmit you will need 4 audio inputs and four
audio outputs. One can use two "sound Cards" but my experience with this has always been problematic. Windoze often encounters conflicts
with two sound cards. Also the way in which windoze handles sound
introduces latencies that can be VERY annoying. Cards using ASIO drivers to some extent side step this problem. It is highly recommended to use a "supported" card when using any version of PSDR.
The cheapest option is to look on ebay for a second hand "supported" card. There are a lot of Maudio Delta 44 cards around and you might get one for less than US$100. These supported cards have 4in and 4 out. PSDR is able to communicate DIRECT with the driver/card and
then gives full volumetric control of the card via the PSDR GUI.
The best of the commercial cards I have used is the Roland FA-66
this card uses a firewire interface the Delta 44 is a PCI card.
The best option is Christos's USB2SDR which has VERY low latency
by bypassing the windoze sound management entirely. Also the USB2SDR
has ptt/keying and facilities to control the Sis570 through an I2c
interface meaning one only USB connection to the PC. This cuts out
a lot of looped PC noise from the receiver.
Overall audio performance wise, The best is the FA-66 followed by
the USB2SDR then the Delta 44. Realizing that the delta 44 itself
is an order of magnitude better than the better industry standard
Regards 73 Eric VK5ZAG
--- In firstname.lastname@example.org, "Alan" <alan4alan@...> wrote:
> ----- Original Message -----
> Subject: [powersdr-iq] PowerSDR-IQ and Ensemble II RX
> > I have some questions about configuring and using PowerSDR-IQ and the Ensemble II receiver. The installation and setup notes by
> > WB5RVZ were very helpful. I am trying to get some additional details on this.
> > 1. To install Micosoft .Net Framework 3.5 SP1, do you need to install the .Net Framework 3.5 and then the SP1? Or is the .Net
> > Framework 3.5 included in the SP1?
> > 2, Is it important to set the device type in "Hardware Config" to "Soft Rock 40"?
> > 3. How does the Freq Cal work? (I looked at the manual, but was not clear to me.)
> I guess you are not going to use the latest PSDR-IQ? <https://code.google.com/p/powersdr-iq/downloads/list>
> Information included.
> 73 Alan G4ZFQ
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