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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

Showing 1 response by spkrplus

spkrplus's avatar
spkrplus
53 posts
 
Elliot,
Your Qs followed by replies.
1. why/how do 16 ohm speakers make amps sound better, with more resolution?
For an estimated 99+% of amps the higher the load impedance the greater is the amp’s current capacity and the more pleasant and agreeable is distortion spectra. A 16 ohm speaker draws half the current of a 8 ohm speaker.

For SS amps, power/voltage is halved for each doubling of impedance, a potential negative for amps with borderline power. For tubes including OTL it’s all upside (at least up to 16 ohm); in some cases like Ralph’s lovely S30 OTL, power increases 50% (45W, +1.5 dB) @ 16 ohm vs. 30W @ 8 ohm. Interestingly, compared to S30 > 8 ohm, 16 ohm has more powerful bass and IIRC even lower bass cutoff! IIRC, with Ralph’s larger amps the 16 ohm power advantage is less than with S30.

2. why speaker cables less critical?
The sum total amplifier load = speaker impedance + speaker wire series resistance. The higher is speaker impedance the less (as a ratio of 100%) does the speaker wire contribute to the load. You hear less cable and more speaker because the latter contributes a higher ratio of the total load.

Lower speaker cable resistance can have similar effect as increased speaker load impedance; the caveat is that cable inductance rises with conductor thickness, so as usual it’s not a free lunch upgrade,


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