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
I’m gonna

1. remove the L pads
 
another advantage: the L pads in the back panel won’t be wired to the crossover/drivers inside, the back will come fully off.

2. annual tightness check (nothing ever loose, but, to sleep better ..)

a. confirm the drivers are tight to the front panel, and
b. the front panel tight to the case 
c. 15" Woofer off the front panel, I can check the paper cone’s condition, it’s been several years.
d. I might drill more mounting holes on the metal ring of the 15" woofer, 4 just doesn’t seem enough for that 37 lb monster (although it is never loose when I check)

3. make a new set of speaker cables using this:

https://www.ebay.com/itm/75FT-CAT7-S-FTP-Network-Outdoor-High-Speed-10Gbps-Shielding-Ethernet-Cable-...

OFC, S/FTP, 24 awg solid strands (8 conductors equivalent to 14 awg)
(might be 26 awg, equivalent to 17 awg, waiting for seller's answer)
12 feet long each, (2+, 2- : 50 foot roll will just do it) 16 ohm nominal.
McIntosh chart says 18 awg, 16 ohms, max 60 feet long.

Unless someone talks me out of it!!!
If you want to add a single resistor to replace the L pad and adjust brilliance (like Lew suggested) Mills are great, those are the ones I use on my speaker and are very transparent, 12W BTW 28 ohms in my case.
Edit: in your case of course you might want to measure the lpad setting for resistance and replace with same value, my 28 ohms is very specific to my room and driver
@luisma31 : Mills are good not great, great are the Vishay ones nothing can beats it.

R.
So I heard Raul and I don't disagree. Practically for a speaker you will need quite a few Vishays per channel which will make it more expensive and more bulkier to install but yeah if you have the money Vishays are supposed to be great and Mills good (like you said)
To me, Elliots findings make perfect sense.
1. A16 Ohm speaker will present a much milder load to any amp designed for 4-8 loads, usually resulting in less distortion. There are exceptions but very rare.
2. As the speaker’s impedance rises, the amp’s output impedance will become less of a factor, equivalent to higher damping factor. The amp will drive the speakers with more control. Frequency ranges where the speaker’s impedance drop even below 8 ohms will present no problem to the amp, again less distortion, more grip.
3. Because of the higher impedance of the speaker, the resistance and impedance of the cables will be less significant.

BR,
Davor, also a Covid recoverer :)
Take care