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8 Ohm vs 16 Ohm drivers


Lostinozz

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I'm in the process of building a pair of speaker cabinets.[sn] I have several drivers to choose from for the midrange and the tweeter horns. My question is; what would the difference be, if any, in using 8 Ohm or 16 Ohm drivers of the same species, other than crossover considerations? I understand there would be a difference in woofers of different ratings but I'm not sure about the others. I've searched the Forum and can't find anything posted although I'm sure this has been covered in the past. Any information you can give me will be more information than I have now, heck, I may even go over to the "Ask Clarence" thread and see what words of wisdom he can bestow on me![:D]

Thanks,

Craig

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Higher impedance will result in less distortion. There are folks who use autoformers for increasing the impedance of drivers with the goal of attaining lower distortion. The zero autoformer is one such device, cost is about 500 bucks per pair. There are a few sites that have reviewed increasing impedance and how it effect distortion. Google zero autoformer.

While it is true that lower impedance will result in the amp being able to produce more watts, the amp will also run hotter.

As a point of intrest, in the heritage line of crossover network, we start out with a 16 ohm mid driver (which actually measures 11-14 ohms) and change the taps on the crossover's autoformer to reduce the drivers level by increasing the apparent impedance.

tap 4 = 3b drop = 2x impedance

tap 3 = 6b drop = 4x impedance

tap 2 = 9b drop = 8x impedance

tap 1 = 12b drop = 16x impedance

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The reason I asked was to determine which drivers I should use in the Altec 288's that will be attached to Altec 803B 8 cell horns or possibly 1005B 10 cell horns (Ihaven't decided yet). These speakers will be used for my detached shop where I have plenty of room for the LARGE cabinets required to fit the horns in.

I have a variety of large format drivers with diaphragms running from 4, 8, 16, 24 Ohm.

I will be pushing these with a Krell KSA100 amp I've owned for 25 years. The Krell folks said it should have no trouble pushing the 4 total Stephens 103LX2 woofers I have for the double base bins, regardless if I run them in paralell or series. They said a 2 Ohm load wouldn't hurt them.

For tweeters I could run either JBL bullets (8 Ohm) or Slots (8 or 16 Ohm).

Any suggestions?

Before someone states the obvious, yes these will be big with absolutely NO WAF, but like I said, these are for my shop and for letting my closest neighbor (1/4 mile away)enjoy them too.[6] They'll also help bring a little music to outdoor BBQ's.

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The decision may also affect your level matching, i.e. if the mids and high are much more efficient the the low end driver, using a 16 ohm driver would be one way to close the gap.

Isn't it usually the other way around, with the mid and high horns being much more efficient that the low section?

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Craig,

I don't think there is any difference in performace between an 8 and an 16 Ohm driver. Power is simply voltage time current. The ratio of this is the impedance. This is simple ohms law. Power = E x I and Zo = E / I. What counts is that the network you use is designed to properly match into the impedance of the driver you choose. If you use a transformer to set the level and have a proper swamping resistor ahead of the transformer you can use either impedance driver by just moving the tap settings.

AL K.

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It depends on the efficiency of each component of the speaker. You'll want to use higher impedance for more efficient devices (squakers / tweeters) and lower impedance for less efficient devices (woofers). If you do it right, you can end up with a crossover that doesn't need to employ any attenuation to match efficiencies - which results in a simpler design, which often sounds better too.

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It depends on the efficiency of each component of the speaker. You'll want to use higher impedance for more efficient devices (squakers / tweeters) and lower impedance for less efficient devices (woofers). If you do it right, you can end up with a crossover that doesn't need to employ any attenuation to match efficiencies - which results in a simpler design, which often sounds better too.

yeah, that's what I was trying to say...

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AlK, DrWho, and Coulter,

Thank you for the information. That confirms what I have gleaned from bits and pieces of past posts in the Forum. I just wasn't positive that my conclusion was correct. Usually I'm about 180 out.

When I get home I'll work on the cabinets (something I'm capable of). When I'm finished I may try to build some crossovers but will more than likely leave that up to one of the experts here on the forum. I would have no problem assembling crossovers of someone else's design but after studying lots of the information that's available, I realize designing them may be a bit over my head.

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On a single driver loaded amp, the amps dampening factor is different at 8 ohms than at 16 ohms. The amps dampening factor is calculated by deviding the speaker load by the amps output impedance. If you increase the speaker load, the dampening factor increases. In years gone by, SS amps with higher dampening factors where more attractive than amps with lower ones.

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  • 14 years later...

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