As far as making the XLR take +4 levels, I've been told this won't happen because of the limitations of the chip's input. AES/EBU standards don't apply, as that is the pro version of S/PDIF, which won't work into an analog input.
In the future, you should be able to take DAX input for your mic audio if you route it through your PC. Frankly, it should work now, but I've not given it a go. But you will be introducing some digital latency when you do so.
As for that rack-o-gear, I run none. I use a nice mic (RE320) run straight in to the flex. TX EQ is not even on. Virtually every QSO results in unsolicited compliments on my audio, with further questions as to what the heck am I running. :)
I think the flex as it is now is capable of very good audio quality. I have a background in audio engineering, so I'm not completely ignorant of what it takes to make things work...but then I also have a "less is more" philosophy. What works for me may not work for others.
There is some room for improvement in the entire AF signal path and the DSP engine in the 6000 Signature series radios has some really cool audio processing feature that we plan to expose in the software once the road map is complete. The 6000s have a lot of potential in this area and we have only seen the tip of the iceberg.
I admit I have given some thought to a mic preamp. I prefer not to have to run things wide open if I can avoid it. Mebbe I need to build one as a project.
Definitely looking forward to other audio processing in the future!
As far as the compressor/expander working well as is... I'll just say that it does enough to even the peaks out, but its got a long way to go before it acts like a good compressor or expander. The boys at Flex got it working well enough to be able to have something functional, and they did a great job at that particular juncture for the time they had. But if you really know how a compressor and expander is supposed to function and feel, you start adjusting it and wonder "What's up?". Joe obviously picked up on this.
There is absolutely no doubt you can get great audio from a nice mic directly into the 6000 series with no outboard gear as is. But remember, the quality of the audio is judged by the guys on the other end, who usually are limited to a 100-2700 Hz receive bandwidth with crappy speakers or a cheap set of headphones, so any good mic (RE320 is a great one - Chinese version of the RE20) will get you 95% of the way there at that bandwidth. For the best audio with a mic straight in, you want to use a mic that has a slightly higher impedance than the typical 100-200 ohm output. Something above 400 ohm will give you a lot more output allowing a better S/N ratio as a general rule, but it is not always the case. It is mic dependent. But you DO NOT want a true high impedance mic.
I practice ESSB a lot and often run at 7.5 KHz wide. When other guys are listening that wide that have good audio monitoring equipment, they will hear issues without outboard processing. But that is a very specialized segment of the hobby, so it's not really fair to even go into that here. But they all agree that the front end of the Flex-6000 series sounds flat from 20-10KHz, which is a great thing.
As Tim mentioned, there are a few things that outboard processing does for you on the input of the Flex-6000 series... or any radio. A good argument can be made to continue to use a minimal amount of outboard equipment. I have to start with the fact that the 6000 series input is limited to -10 dbV consumer levels (a bit higher than -10 dbV actually). So it can comfortably take mic level to a modest level of preamplification. While a good mic works great into the input of the 6000 directly, a minimalist outboard equipment approach is better hands down; on ANY rig I might add. The first thing is to amplify the mic; pushes S/N up a lot. Then turn on the outboard compressor (careful on adjustment and don't overdo it) and you squash the input audio modulation envelope in such a way that you can stop loud talking peaks from clipping the input of the radio and still sound loud at the other, end even when talking soft. This evens out output RF power like the onboard compressor, BUT keeps you from clipping the input side of the rig and gives a much better S/N ratio, which gets noticeable when the bands have little noise.
The only caveat I give on external audio processing is RF ingression. If you do not have a good handle on your RF in the shack (or even if you do) adding those extra wires can bite you in the rear and cause you to add isolation and additional grounding.
So bottom line:
- Joe, have patience my friend. We'll get there with the onboard processing.
- Running just one little cheap preamp/compressor box can make a big difference in your input AF S/N ratio on ANY rig, not just the Flex-6000 series.
I also am constantly getting "fantastic" audio reports with a Heil PR22 into the BAL-TRS, after tweaking the EQ. ( I can't understand why anyone would hook up a new mike and not spend 15 minutes with another receiver, or at least looking at their own TX Spectrum on the panadapter while making a few adjustments.)
But just for fun I ran my mike through a USB mixer, through "Stereo Tool," and back into the rig via DAX. It didn't get me a whole lot extra, but was fun to play with. I haven't really fine tuned it all that well, yet. The exception was that the ESSB guys on the low end of 80 said that I was getting some great richness using Stereo Tool when stretched out to 6K wide. (I did go out to about 8K once but felt too guilty!) The biggest problem I had was about 1/4 second latency on transmit. I probably could have achieved the same thing with judicious adjustment of the inboard TX EQ on the 6500. But I didn't want to mess up my other settings. (TX profiles will make this more easy to play with.)
As far as "normal" bandwidth operating, I am looking forward to definable TX profiles that store all of the bandwidth, EQ, gain & compression parameters. I tend to "gadfly" about between rag chews and DX hunting and am always changing my TX Bandwidth. I would change EQ settings and compression along with it but it takes too long and too many mouse/keystrokes. Profiles, and the addition of some more aggressive compression/processing for added DX/weak signal punch (just a bit more than we can get now) things will be great.
But I agree with the others...It is really good now, and I am content to wait until the other features are delivered before adding extra processing (Unless it is really easy and won't sidetrack the developers!)
For the future? Here are some dreams...
TX Profiles (already on the roadmap)
Definable Parametric EQ?
Or the ability to draw your own EQ pattern as Stereo Tool does?
Multiband compression with definable compression level and post-compression output level for each band? This would be killer!
Noise Gate/Downward Expansion.
Ability to define the PTT/Footswitch to DAX audio input channel if desired.
Just a little dreaming... And I still don't know enough of the capabilities Tim is talking about to even know what I want!
Keep up the good work!
Ken - NM9P
I think I remember when you visited us at the bottom of 80M. Fun stuff, huh? Sorry you felt guilty.
Nice wish list. I'll comment on a couple.
I for one would LOVE to see a parametric instead of a graphic EQ with ability to drag points and change filter Q, as it is much more usable and WAY more effective. (I do that outboard currently.) However, it would be a stretch for a lot of hams, as it is way more complex to adjust. But why not? Very useful and anyone can learn to use it in time.
Something as esoteric as multiband compression would be a lot less useful in the ham radio world for a number of reasons, at least on normal SSB. First, most people really don't really have the subtleties down on proper adjustment of a single band compressor or understand how that affects transmitted frequencies. Now add in a multiband version, and I could see heads exploding and some really screwed up audio. The only people that would get any real benefit would be AM and ESSB guys (especially AM) because without being at least 5KHz wide on TX, it's affect would be almost negligible.
Downward expansion (just expander for short, which is what most know it as) is already there coupled to the compressor, although its not really usable yet as it has a really low threshold which is obviously not yet adjustable.