Altec Experts - 8ohm vs 16ohm? Pros/Cons?

ictwoody

I like vintage gear — my preamp is from 2007.
Hey guys.

I have a bunch of Altec drivers I've been collecting to do some DIY box projects with, one of which is a copy of the JE Labs 414/32A/802 speakers — see link here.

http://jelabs.blogspot.com/2014/01/altec-2-way-horn-system-redux.html

With his crossover detailed here.

http://jelabs.blogspot.com/2014/01/altec-2-way-xo-update.html (attached pic is his with updated cap values for 8ohm option. The woofer is run full range.)

I will be making a quick day trip down to Great Plains Audio which is only about 2.5hrs from me to drop off my 414-Z's and some other stuff for repair and service soon and I have the opportunity because of having them reconed, to choose if I want 8ohm or 16ohm VCs installed. I also have some 802's which need new diaphragms and a remag, so again, I have the choice of 8 or 16ohm phrams.

My suspicion is to have them both made 8ohm... but I wanted you guys to weigh in. Is there any reason I would want to keep them 16?

Thanks!
- Woody

File Nov 14, 5 51 05 PM.jpeg
 
Bl significantly impacts Qes, essentially the motor's electrical damping ability. This is one of the reasons tube amps which have a fairly low damping ability will often mate a little better with 16 ohm drivers/systems. How significant a difference 8 or 16 makes will vary from situation to situation.

OTOH, well mated box and woofer are well mechanically damped and don't rely as much on the amplifier to apply the brakes when needed.

Also worth considering are cost and value. Specifically, if you are going to build passive networks, how does 8 or 16 ohm components affect the cost of your XO build as well as what does re-coning an originally 16 ohm classic woofer to a non-stock impedance do to it's value?
 
I have asked a similar question, “which is better for hifi, 8 or 16 ohms?”. The answers I have received are the same as in this thread, there is no definitive answer. It depends on a lot of factors.

One thing Bowtie mentioned, which I do consider myself, is passive xover component cost.

If you are into boutique caps, the 8 ohm crossovers will cost more. If you are into cheap caps (like me, I use motor runs), the 8 ohm xovers will be cheaper to build.

This is because in an 8 ohm crossover, the cap values are doubled and the coil values halved. And in a 16 ohm crossover the cap values are halved and the coil values doubled.

For me then, my main expense is the coils (big one are expensive!).

Also like Bowtie mentioned, whether you are using a tube, or SS amp. I run all SS equipment, and usually stick with 8 ohm. Even though one set of speakers are 16 ohm, and my SS integrated runs them just fine. It is just what I happened to have though
 
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