Need Help Waterfall in DM780 Distorted Tried all Settings in DAX Levels

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I got my new Flex 6300 on Wed and I have been trying after work since then to get it to play with HRD DM780.  Just today I got DDUTIL 3.0 loaded and can run HRD DM780 without rig control front end.   I tried youtube recommended soundcard settings for sample rate adjustment.  I have set DAX receiver gain to full scale "0" and copy about 75% of PSK conversations. I am running windows 7 professional.  I am so aggravated and frustrated with DAX and audio settings I am ready to throw this 6300 in the yard.  I have been running the Flex 3000 on the same computer with powersdr with no issues with HRD and DM780.  Do I need to run the 6300 on a completely separate machine?  I did not anticipate this kind of aggravation or I would have never upgraded.
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Posted 5 years ago

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Tim - W4TME, Customer Experience Manager

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Terry - I can appreciate your frustration and the technical recommendations made here are sound.

I suspect that your issue is not just one specific issue, but possibly has several contributing factors.  I have read through this post and I can offer some insight and feedback on what has already been said.

First off, a Core 2 Duo CPU is below minimum recommended processor to use with SmartSDR and the other SmartSDR ancillary applications (CAT & DAX).  
Here is the excerpt from the web site (

Hardware Requirements
Minimum required CPU for SmartSDR is an Intel i3 2100T or an AMD Athlon Phenom II and greater. Lesser processors may not perform adequately when displaying multiple or full screen spectrum displays.  However for the optimal user experience, as most hams run multiple applications along with SmartSDR for Windows such as loggers and digital mode programs, a quad-core CPU or greater is highly recommended.

This minimum recommendation does not take into account running third-part apps that can be significant resource consumers.  The advice you received about your PC being under powered is warranted.  In addition, HRD consists of a lot of individual applications and they can consume resources and result in system latency that is not reflected in metrics like CPU utilization and memory consumption.  When dealing with real-time audio, DPC latency is very significant.  Yes, your PC may have worked well with your FLEX-3000, but SmartSDR is very different than PowerSDR in the way it uses PC resources so that comparison is not a good validator.  One caution with your IT friend; a lot of PC IT folks do not have a lot of experience with running Windows with real-time audio processing applications (DAX is one of these).  It takes digging into the internal system latencies to get a full picture of what is going on.  I have seen high-end PCs that have horrible system latency and they don't work well with real-time audio processing apps.

The DAX driver can be susceptible to buffer alignment issues if the CPU utilization is high along with long duration DPCs.  We are aware of this issue, we think we know the source of the problem(s) and are working on addressing them.  Hopefully we will have possible solution in the near term.
Second, I would recommend some basic troubleshooting techniques to determine the source of the problem.  The key technique is to perturb the system and see how the problem tracks.  In that regard, I would try a different digital mode program, like Fldigi.  Here is a nice video on how to set it up (  If the problem show up with Fldigi, then you know the issue is not with HRD.  Otherwise there is a good probability that the issue is with HRD.

The suggestions about selecting the MME audio driver if one is available is a good one.  It is the most compatible of all the rest because it isn't a low latency audio driver.

Don't throw in the towel just yet. I think you may be asking the Core 2 Duo to do a little more than it is capable of doing.