Perceived quality of TX audio when PS engaged
Posted: Sat Sep 24, 2022 8:51 pm
(Perhaps this belongs in another sub-forum?)..........I have been racking my brain for a long time over the perceived quality of audio when PS is engaged (this, I did much before I started using PS myself which is very recent). What I am writing is clearly an over-simplification (or, alternatively, making this much more complex or convoluted than it needs to be), but I would value comments from others.
The ANAN platform brings a plethora of professional audio sculpting tools and that is only one of the reasons for my wanting to acquire an ANAN (a little over 1 year ago) and, being able to use PS is a huge "bonus." In my case, I do process audio inside either a DAW or a VST Host, before the resulting audio is fed into the radio. I often receive unsolicited reports on the quality of my audio.
Yes, to most of you, I may be down-right off-base or nuts and getting into the weeds that just isn't worth spending time on. Also, there are so many different ways to mold audio that attempting to decipher what I (and some others, see below) may or may not be causing what I am hearing just doesn't make sense. Quality of headphones and/or reference monitor speakers and the listener's ability to perceive of frequencies and the separation among sub-bands of lows, low-mid/mid/high-mids/highs (I have striven to "train" my ears in various ways too) play a big role. I don't claim to have "golden ears" either (VERY few people actually possess them), but I do come from a musical family and have been exposed to different sorts of music and vocals starting at a very early age. I even had the audacity and gall to tell a professional pianist visiting our home (I was in my late teens at the time), playing a piece of classical music, that he went off-key at which point he stopped, cracking in a smile, and said that I was right on the money.
I would like to better understand why it could be that I detect a very slight deterioration in the quality of the transmitted audio (a few other hams using ANANs and PS have echoed what I am writing here with some being professional audio engineers). Some also don't avail themselves of the very significant decrease of IMD products that using PS brings, so they don't always switch it on. On the other hand, many do not hear any difference so I am clearly in the minority which is fine by me.
It is hard to put my finger on this, but I have conducted several A/B comparisons with PS ON or OFF with a few different stations that put out very strong high quality SSB signals, with nothing else changing in their audio chains. With PS on, I am hearing a slight "smearing" or "feathering" effect on the very low-end (80-120Hz) of an SSB signal, in a way (my interpretation), reducing the amount of "separation" between the very lows and the frequencies above. This effect makes the perceived audio sound just a smidge less transparent or "clean" in my ears (well, ears don't process the audio but our brains do). Or, perhaps, it is the highs that are being somehow de-emphasized, rendering the overall transmitted signal just VERY little less articulate. Some operators roll off at 0 Hz when their TX bandwidths are 4K or wider too. Perhaps, the frequency at which the low-end roll-off is set plays into my perception of their signals when they switch PS ON and OFF? From a theoretical perspective, there really isn't much information at 0Hz ! Even professional music studios that mix/master music with scores of "stems" (or tracks) don't work at 0Hz so why should we, as ham radio operators? What would be the benefit?
OK, I got it out of my system....you're welcome to shoot me down. It wouldn't be the first time !
Juha
NI2M
The ANAN platform brings a plethora of professional audio sculpting tools and that is only one of the reasons for my wanting to acquire an ANAN (a little over 1 year ago) and, being able to use PS is a huge "bonus." In my case, I do process audio inside either a DAW or a VST Host, before the resulting audio is fed into the radio. I often receive unsolicited reports on the quality of my audio.
Yes, to most of you, I may be down-right off-base or nuts and getting into the weeds that just isn't worth spending time on. Also, there are so many different ways to mold audio that attempting to decipher what I (and some others, see below) may or may not be causing what I am hearing just doesn't make sense. Quality of headphones and/or reference monitor speakers and the listener's ability to perceive of frequencies and the separation among sub-bands of lows, low-mid/mid/high-mids/highs (I have striven to "train" my ears in various ways too) play a big role. I don't claim to have "golden ears" either (VERY few people actually possess them), but I do come from a musical family and have been exposed to different sorts of music and vocals starting at a very early age. I even had the audacity and gall to tell a professional pianist visiting our home (I was in my late teens at the time), playing a piece of classical music, that he went off-key at which point he stopped, cracking in a smile, and said that I was right on the money.
I would like to better understand why it could be that I detect a very slight deterioration in the quality of the transmitted audio (a few other hams using ANANs and PS have echoed what I am writing here with some being professional audio engineers). Some also don't avail themselves of the very significant decrease of IMD products that using PS brings, so they don't always switch it on. On the other hand, many do not hear any difference so I am clearly in the minority which is fine by me.
It is hard to put my finger on this, but I have conducted several A/B comparisons with PS ON or OFF with a few different stations that put out very strong high quality SSB signals, with nothing else changing in their audio chains. With PS on, I am hearing a slight "smearing" or "feathering" effect on the very low-end (80-120Hz) of an SSB signal, in a way (my interpretation), reducing the amount of "separation" between the very lows and the frequencies above. This effect makes the perceived audio sound just a smidge less transparent or "clean" in my ears (well, ears don't process the audio but our brains do). Or, perhaps, it is the highs that are being somehow de-emphasized, rendering the overall transmitted signal just VERY little less articulate. Some operators roll off at 0 Hz when their TX bandwidths are 4K or wider too. Perhaps, the frequency at which the low-end roll-off is set plays into my perception of their signals when they switch PS ON and OFF? From a theoretical perspective, there really isn't much information at 0Hz ! Even professional music studios that mix/master music with scores of "stems" (or tracks) don't work at 0Hz so why should we, as ham radio operators? What would be the benefit?
OK, I got it out of my system....you're welcome to shoot me down. It wouldn't be the first time !
Juha
NI2M