Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Amplifier Discussion => Topic started by: joecool85 on November 03, 2011, 01:58:34 PM

Title: 3 speakers, how does the power flow?
Post by: joecool85 on November 03, 2011, 01:58:34 PM
I want to make a cab with three speakers and have an output of 4ohms.  I figure I will use two 4 ohm speakers wired in series, then wire that set in parallel with an 8 ohm speaker making the total load 4 ohms.  Would each speaker get the same wattage or would it split the watts between the two 8ohm loads, IE - one speaker gets 50% and the other two get 25%?
Title: Re: 3 speakers, how does the power flow?
Post by: KMG on November 03, 2011, 03:29:19 PM
QuoteI figure I will use two 4 ohm speakers wired in series, then wire that set in parallel with an 8 ohm speaker making the total load 4 ohms... or would it split the watts between the two 8ohm loads, IE - one speaker gets 50% and the other two get 25%?
Exactly: 50%-25%-25%
Title: Re: 3 speakers, how does the power flow?
Post by: joecool85 on November 03, 2011, 03:36:35 PM
That's what I thought.  I may just end up building a 1x12" cab to put my Dean Markley into...or build a 1x12" cab, make my Dean a head and build a small 1x8" for the stock Dean speaker.  Ideas, ideas, ideas...
Title: Re: 3 speakers, how does the power flow?
Post by: aoresteen on November 03, 2011, 04:41:45 PM
I did that exactly when I built my 3 speaker cab for my Squier SP10 amp

http://www.ssguitar.com/index.php?topic=870.0

Here's the cab:

(http://i36.photobucket.com/albums/e5/aoresteen/Squire%20SP10/7customcabbackopen.jpg)


The Math:

The 6" Jensen is rated at 15 watts
The 8" Jensen is rated at 20 watts
The Clestion 10" is rated at 60 watts.

The 10" is 8 ohm and gets 50% of the load so it could handle a 120 watt load delivered to the cab
The 8" Jensen is 4 om and gets 25% so it could handle an 80 watt load delivered to the cab.
The 6" Jensen  is 4 ohms and can handle a 60 watt load delivered to the cabinet.

Therefore the MOST power the cabinet can handle safely is 60 watts otherwise the 6" Jensen will blow.

At 60 watts delivered to the cab the 6" Jenson will get 15 watts, the 8" Jensen will get 15 watts and the 10" Celestion will get 30 watts, total of 60 watts, all within their specs.
Title: Re: 3 speakers, how does the power flow?
Post by: joecool85 on November 04, 2011, 08:08:35 AM
Thanks for sharing aoresteen.  Maybe instead of a 3x8" I will consider doing something similar to what you have done and use different size/rating speakers to make an interesting stack.  I kinda like your 6,8,10 cab.  I can't wait to hear some sound clips of it and impressions as far as how it handles clean and od tones etc.
Title: Re: 3 speakers, how does the power flow?
Post by: dan stanton on December 25, 2011, 07:18:49 PM
You could use a crossover network.