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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.
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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
Post removed 
three_easy_payments's avatar
three_easy_payments
2,097 posts
 
very cool product @tvad   I was unaware of it and it would fun to experiment with. I will say, it's nice that my amplifier has 4, 8, and 16 ohm taps and I have spent a lot of time testing various taps along with differing NFB settings.

But why would anyone need this when Einstein above tells us that 4 ohm speakers are always best in every application?  The YouTube video of some guy (possibly a wizard?) proving that a louder a noise can be made by presenting a 4 ohm load to an amp compared to an 8 ohm load was like magic.  That guy is a genius - he figured out that halving the load impedance will double the power output of an amplifier and make louder noises.    
emrofsemanon's avatar
emrofsemanon
292 posts
 
i wonder why there is no move to democratize 4-ohm equipment, why it continues to be very expensive and exclusive.
oldhvymec
5,101 posts
 
I usually wire mids and highs at 8-16 ohms. I use small planars, or ribbons, both like the higher impedance on valve amps especially.

SS a little different, Pass design puts a smile on my face at just about any impedance.. Not often I wire with a single driver, bass, mids or highs.. Subs, I still wire at 8 -12 ohms. Just less distortion..

Regards
lewm
12,856 posts
 
The Zero (Speltz) Autoformers are not a free lunch. As with any transformer, they trade off current and voltage. So if you mate an amplifier with a high-ish output Z to a speaker with a low input Z, via the Zero, you lose voltage in direct proportion to the gain in impedance seen by the amplifier. This affects apparent amplifier power. It does work, but it’s not a perfect world. I happily used the Zeros for many years as an interface between my Atma-sphere amplifiers (OTL amplifiers with a high output Z) and my Sound Lab M1 speakers, which had a midrange impedance dip down to 2 ohms and was under 5 ohms impedance across a considerable portion of the midrange. The Zeros made it possible to drive them. Then I traded my M1s for a pair of Sound Lab 845PX speakers. The match was just barely acceptable, because the 845s + Zeros were sucking more amplifier power than the M1s, but with the intellectual input of a guy in Australia and by changing one of the two audio step-up transformers in the SLs and ripping out the crossover components, I was able to completely eliminate the impedance dip typical of SL ESLs. (Ralph knows this story very well.) In fact, my 845PXs now present an impedance that is never lower than 20 ohms from around 200Hz to 5kHz, and they are also much more efficient, for technical reasons too arcane to go into here. The load presented by the Sound Labs is just heaven for my Atma OTLs, and I don’t need autoformers. So, use ’em if you need ’em, but it’s still best to select either a speaker suitable for your amp or vice-versa, in terms of impedance.
To the OP. I advise you to set those controls the way you like them, then measure R across each rheostat, then substitute discrete resistors of that value, one for each rheostat (if I am correct that each speaker has 2). This will get you a big upgrade in clarity. When you do that, select very high quality resistors of very high wattage rating; that also pays off.

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