Grateful Dead Music Forum

A place to talk about the music of the Grateful Dead 

 #79480  by rugger
 Fri May 07, 2010 8:50 am
What's the difference between an 8 ohm speaker and a 16 ohm? can you mix and match (I'm guessing not)? Is one louder than the other? Should you wire in series or parallel? I'm trying to take the plunge with the K120's and I'm seeing different stuff and I don't have much of a clue.

BTW, there is a pair of 16ohm k120 that just went up on ebay.

John in San Diego
 #79482  by JonnyBoy
 Fri May 07, 2010 9:28 am
check the board, there has been much talk about this subject, but for s#!Ts and giggles here is what I posted for "converting from closed back to open back cab"
This is a diagram to help you set up speakers. what kind of amp do you have and what are the speakers and values in them? The manufacturer will put the best values for the amp stock, its best to follow them, but some amps are more versatile.
 #79496  by ugly rumor
 Fri May 07, 2010 12:00 pm
If you call me, 720-389-7137 before 3:30 Mountain zTime, I'll explain it to you in detail.
 #79497  by strumminsix
 Fri May 07, 2010 12:06 pm
U.R. has some good info so call him! But as I understand it:

"What's the difference between an 8 ohm speaker and a 16 ohm?"
= 8 ohms. Ohms = resistance

"Is one louder than the other?"
If loaded together in parallel will have 12ohm load and the 8o will be louder

The " generic standard" buy 8ohm speakers for 2x12 cabs and 16ohm for 4x12 cabs.

When you think of ohms and wiring you need to consider # of speakers, their ohms, wiring (series/parallel) and the amp.

There is too much information on-line and posted here to go much further but wanted to help get ya started since many resources skip the very basics!
 #79514  by ugly rumor
 Fri May 07, 2010 1:54 pm
You have to be aware of the parameters of your amplifier. I checked the link Johnnyboy sent you, and it is correct so far as it goes, except it says that a tube amp puts out the same amount of power regardless of the resistance and that solid state puts out more power to less resistance. That is wrong. They both put out the same amount of power regardless of resistance, just with less resistance the SS will be able to use more of its power, where a tube amp has a transformer that will match impedance.

If you want 8 ohms, you can wire two 4 ohms in series, or two 16 ohms in parallel. The amplifier doesn't know the difference, as the total resistance will be 8 ohms. The advantage to using 16 ohm speakers is that they will absorb spikes in power better, and will be harder to blow. The disadvantage is that you sacrifice efficiency. The advantage of using 4 ohm speakers is the better sensitivity (assuming quality is consistent) and more versatility. 8 ohm speakers are ideal for single speaker or series-parallel wiring, or if you want a 4 ohm load with two speakers. Some people consider a highly efficient speaker to sound harsh. That's part of why vintage Altecs, JBLs, EVs, etc. are desirable for tone.

If you have a choice, get speakers that handle more than your amplifier can deliver. A 50 watt head should have at least a 75 watt speaker, as the head will still send spikes, and you want a speaker that is rated high enough to weather those spikes. If you have a speaker of unknown power handling capability, use the EC code to determine the manufacturer and call them. They should be able to tell you the power handling capacity of the speaker and who it was made for. Then call them and find out where they used it. That is generally very helpful to know how you should use it (or not!).

Hope this helps some!