[TenTec] Yaesu comparison

[Richards]

On 2/3/2013 4:13 PM, Rick - DJ0IP / NJ0IP wrote:

   So on a given day, you might
> clearly see that a radio with a 3kHz roofing filter
sounds better than ...
	

	You some good points, and this particular comment 	
	raises a different, but closely related, aspect of
	comparison testing - namely the very subjective
	determination of which radio "sounds better."

Bottom Line Question --

	CAN WE REALLY DETERMINE WHICH IS THE BEST
	RADIO IN A SIMPLE A-B TEST?    Can we really
	account for ALL the salient factors which can
	affect our decision?

My half-baked notion:

	Determining what radio sound best is, at best,
	a very subjective matter, turning on many
	aspects and factors along the RF and audio
	chain.  For example, few hams agree on what
	sounds "best" - witness the endless hullabaloo
	over external speakers. Witness the debate over
	the value of DSP filtering vs audio quality.

	People, in general, favor "single-factor" analysis,
	constantly advocating what is the single "reason"
	for whatever they are trying to explain.   But I
	believe in multiple causation  - that much of what
	we observe can only be explained by considering
	a multitude of causative factors.   Focusing on
	roofing filters, without considering the "rest of
	the story" seems a bit limiting.
	
	Although I am a mere novice concerning radio
	design engineering, I presume a 3 kHz filter may
	"sound" different from a 1.8 kHz filter in the same
	relative point along the signal chain.  Moreover,
	it seems logical, if not correct, it will make a
	material difference exactly where and how you
	implement those filters.   Merely altering the
	audio EQ frequency curve can have a substantial
	effect on what we hear - effectively acting as a
	high or low cut 	filter, eliminating some noise and
	signal data the 	RF filtering passed through.
	
	Each radio will be different in these respects,
	affecting any A-B testing we might perform.

	But wait, ... there is more!  I suppose different
	audio components, different RF and audio circuit
	designs,  different audio EQ,  different low cut
	and high cut filters,  different pass band
	filters,  the different "skirts" on all filters in
	question, the differences in the presence and
	amount of digital artifact in very different
	DSP schemes, and a host of differences all
	have a determining impact on what we hear.
	I don't expect any two same-make and model
	radios will sound exactly the same.

	To me the acid test is the most subjective:

		Is the other ham easier to understand
		on one radio versus another?  On which
		rig is he more INTELLIGIBLE.

	Overall intelligibility is a function of ALL the
	circuits, and ALL the filers in the rig... not just
	one filter considered in isolation.   I wonder if
	focusing on front end roofing filter schemes
	will tell us enough to determine which is the
	better radio.   I just want to be able to hear
	and understand the guy... will all of this make
	him more intelligible on one rig compared to
	another - TO ME, across the desk, not to one
	or another RF stage in the rig - does it make
	it easier to capture and understand his signal?

	In a recent thread, a qualified and experienced
	operator disparaged Omni VII audio quality.  He
	was sincere and technically well informed, and
	I respect his opinion.   In contrast, however, I
	LOVE the audio on my Omni VII - for largely the
	same reasons he disparaged it !   TO MY EARS,
	signals are more INTELLIGIBLE on it, than on
	many other radios.

	This whole issue of "sounding good" is related
	to the debate over DSP artifact and overall audio
	quality.   The ideal is for DSP to remove noise,
	without adversely affecting audio quality.  But
	that is merely an ideal, which does not occur in
	real life,  so, ultimately, the debate turns on
	whether or not one can accept the inherent
	digital artifact and distortion, or not.   There is
	no free lunch, especially when it come to
	digital artifact and DSP filtering... but, for me,
	the acid test is, again, whether or not the filter
	makes the other guy more intelligible and easier
	to understand.   Sometimes it is a handy tool
	for doing just that... while other times, it
	makes it more difficult to understand the bloke.
	Another case of having a too much of a good
	thing.   I can accept the trade off - at times -
	while other guys find the artifact and distortion
	anathema, and cry foul at any level.   And we
	are all entitled to our opinion - having paid
	our "dues" through the price of the rig.

	For me, the best sounding radio is the one that
	makes the other ham easier to understand - after
	all I figure we are doing "communications grade"
	radio, with the emphasis is on communicating
	a message clearly, not on how good we sound
	doing it.

	Therefore, I am a tad skeptical about any proposed
	A-B comparison test where all these OTHER factors
	are not fully considered, as I doubt few of us are in
	a position to perform any test where they are
	fully cancelled or neutralized.

	How do we cancel all these OTHER factors
	out when making any A-B comparison ???
	
	Considering the front-end roofing filter seems
	a tad narrow for my taste - whereas one rig may
	pass more desired signal through the roofing filter,
	it may end up clipping it later in the RF and audio
	chain, so the result may be worse than another
	rig that passes less through he front filter, but
	does a better job processing and preserving the
	signal down the line.     Only what reaches my
	ears matters to me...

	(I say all this more as a question, than as statement
	of fact.  I still need to learn a lot... so I don my
	Teflon suit and await my fate...)

	      ;-)


	
> I will repeat what I said earlier:  what we witnessed was a pretty
> meaningless test, because we have no knowledge of how each radio was set up.
> RF Gain?  Attenuator?  AGC?  Bandwidth?  Passband tuning?  Maybe it was
> legitimate and fair, maybe not.  We have no way of knowing because the guy
> never said squat about the setup.


	I agree.  My TS-590s is supposed to have
	better receiver specifications than my Omni VII,
	but I can easily set either rig up to beat the
	other one in a side-by side A-B test scenario -
	whether using different RF settings or different
	audio settings, all using the same antenna,
	speaker, etc.   And neither will perform its
	best using the respective default settings, so
	you cannot just set them to factory default
	settings and think the comparison is honest
	or fair.     (Although I like the Omni VII default
	settings better than I like the TS-590s default
	settings...)

	Sidebar... Both are good radios... but just for
	the record, I think it is easier to dial in a weak
	signal, and hear what he is saying with the
	Omni VII - the wider, smoother, more variable
	range of the RF-GAIN control is the most
	salient difference.  I can get the same result
	on both rigs, but getting there is quicker and
	easier on the Omni VII.)
	


Remember...
	You can only fool yourself...  and I highly
	recommend it !      ;-)



Just MY take... I still gotta lot to learn!
____________________  K8JHR ______________





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