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16 ohm speakers: any amp sounds better with more resolution. speaker cables less critical.

First,
  
Thanks to anyone who responds with whatever answers/opinions/advice comes from this. I'm retired, covid bound, Donna is taking care of everything holiday related, too much time, always curious.
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I happened across this in an old thread started by Ralph (atmasphere)

"Sixteen ohms, BTW is a very simple means for getting more resolution out of your system, as nearly every amplifier made sounds better on 16 ohms than it will on 4 or 8 ohms. Speaker cables become far less critical too."

My speakers are 16 ohms (Electrovoice horn tweeter, horn mid, 15" woofer, crossover, rheostats, from 1958).
Extremely efficient, I have more than enough power. Amp, now and in the past all had 16 ohm taps.
Of course I can hook them up to my Cayin's 8 ohm taps now and listen, but facts, opinions, advice, to learn is good.
...........................


Lots of Questions? 

1. why/how do 16 ohm speakers make amps sound better, with more resolution? 

2. why speaker cables less critical? perhaps this is why I/we don't hear cable differences in my system?
I'm using my homemade twisted pair of cat 5 now (8 individually insulated small diameter solid core).

3.  to get exterior bias control: use 8 ohm tap for my 16 ohm speakers? (get alternate amp 4/8 no 16 tap,)

lose advantage(s)? 'sounds better'; 'more resolution'; 'speaker cables less critical'? 

this says slightly more mids:

http://blog.hughes-and-kettner.com/ohm-cooking-101-understanding-amps-speakers-and-impedance/

I can fine tune my speakers via their two rheostats: 'presence' and 'brilliance', so not really an issue for me.

4. Importance of Bias Control

how important is Bias? (I don't care about heat, power output, or tube life, just as bias affects sound). Frankly, using vintage tube receiver Fisher 500C, 800C and Fisher Mono Blocks 80Z, I have never checked or adjusted bias. I just put the control in the center position when cleaning insides/controls.

I have always used 16 ohm taps of various vintage tube and SS amps and newer current tube Cayin A88T. (original version, the only one with 16 ohm taps). It's bias control is internal, versions with safer external bias do not have 16 ohm taps.

5. replace their two rheostats? ('presence' and 'brilliance': copper wire-wound on ceramic body, mid/neutral position).
I have them in neutral position now, l/r frequency response equal.   

do I need to keep rheostats 16 ohms? use 8 ohm rheostat with 16 ohm drivers?

sales sheet says 16 ohm, but data sheet shows range 1.0 to 5k ohms. 

https://www.mouser.com/datasheet/2/303/controls_rheostats-1228697.pdf

does that mean, the drivers will draw whatever they draw (varies thru frequency range anyway), doesn't matter as long as rheostat range starts 1.0 ohm, extends past say 100.0 ohms?

https://www.mouser.com/datasheet/2/303/controls_rheostats-1228697.pdf

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thanks, Elliott











elliottbnewcombjr
charles1dad's avatar
charles1dad
10,250 posts
 
Hi @danvignau, 
Reading Ralph's clearly written explanation it isn't difficult for me to understand why this is the case. As of yet I haven't come across a contrary explanation that reasonably refutes him.

An easier high impedance speaker load (Less current demand) would seem quite beneficial for all amplifiers. I don't see the rationale that a more difficult lower impedance (Higher current demand) to drive is a more positive circumstance for an amplifier. 
Charles 
three_easy_payments's avatar
three_easy_payments
2,097 posts
 
My 96dB/10ohm speakers sound much better on my amp's 16ohm taps than the 8 ohm.  The 4 ohm taps are almost unlistenable.  The 16 ohm taps bring out so much more richness, nuance, and detail.
cisgo
30 posts
 
A question I always was curious about. My amp (FW J2) rates at 12w 4 ohms and 25w into 8. Yet when I connect my 16 ohm speakers ( Spatial TM) they rate back to around 12w. Never really understood how it worked that way. Figured I’d jump into this one and see if anyone had a brief explanation, thanks. 
elliottbnewcombjr OP
5,363 posts
 
cisco,

did you get #'s reversed?

typical amp would be 12 wpc at 8 ohms, double at 4 ohms, i.e. 25 wpc at 4 ohms.

If your transformer does not have a separate 16 ohm winding, then if you hook up a 16 ohm speaker to an 8 ohm tap, _____ wpc?

sonically, this article says the mids would be boosted slightly

http://blog.hughes-and-kettner.com/ohm-cooking-101-understanding-amps-speakers-and-impedance/
lewm
13,030 posts
 
Elliot, What you say to Cisco (Cisgo) may be true for an SS amplifier but for a tube amplifier, especially a transformer coupled one, the reverse is more likely, for a given tap on the output transformer:  An amplifier that makes 12W into 8 ohms might make only 6W into 4 ohms.  This is not always the case, and actual measurement is in order.  Likewise, an SS amplifier is likely to double its power into 4 ohms vs 8 ohms, provided it can deliver the needed additional current, which depends upon the power transformer.  But Cisgo apparently owns a First Watt amplifier, designed by Nelson Pass, one of the best and most innovative of all designers of SS gear.  In the First Watt series, he is experimenting with different topologies and different types of output devices.  So if Cisgo's information about his own amplifier comes from NP, I would accept it as gospel.  And Cisgo, if you want to know why the power rating changes as you say, ask NP.
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