Menu
Carvin Audio
0
  • Audio
    • TRC Column Array Systems
    • Subwoofers
    • Loudspeakers
    • Power Amplifiers
    • In-Ear Monitor Systems
    • Wireless Guitar/Bass Systems
    • Wireless Microphone Systems
    • Power Conditioners
    • Microphones / Direct Box
    • Speaker Parts
  • Guitar
    • KOA Acoustic Guitar Preamp
    • X1
    • Legacy Drive- VLD1
    • MACH100 100W Pedal Amplifier
    • WG5 Wireless Guitar System
    • V112E Extension Cab
  • Bass
  • Blog
    • Audio Info & Education
    • Guitar/Bass Amp Info & Education
    • News and Events
  • SALE
    • On Sale Now
    • Gift Cards
    • Newsletter
  • Rewards
  • Financing
  • Support
  • SINCE 1946
  • Sign in
  • Your Cart is Empty
Carvin Audio
Carvin Audio
  • Audio
    • TRC Column Array Systems
    • Subwoofers
    • Loudspeakers
    • Power Amplifiers
    • In-Ear Monitor Systems
    • Wireless Guitar/Bass Systems
    • Wireless Microphone Systems
    • Power Conditioners
    • Microphones / Direct Box
    • Speaker Parts
  • Guitar
    • KOA Acoustic Guitar Preamp
    • X1
    • Legacy Drive- VLD1
    • MACH100 100W Pedal Amplifier
    • WG5 Wireless Guitar System
    • V112E Extension Cab
  • Bass
  • Blog
    • Audio Info & Education
    • Guitar/Bass Amp Info & Education
    • News and Events
  • SALE
    • On Sale Now
    • Gift Cards
    • Newsletter
  • Rewards
  • Financing
  • Support
  • SINCE 1946
  • 0 0

Extension Speakers: Quick Tips for Musicians Part 2

January 27, 2017

212 Extension Cabinet

In the first part of this article we learned the basics of configuring extension speakers- as long as you know the total impedance load of your cabinet(s).

So How Do You Calculate the Total Impedance Load?

I'm so glad you asked! Because when it comes to amplifiers they have a limit as to how low the impedance can be without effectively shorting the output, and there is a practical limit to how high it can get and still utilize your speakers efficiently. When you plug that extra cabinet straight into your amp via the extension speaker output you are "parallel-wired" because the jack connects the positive side of both speakers to the positive terminal of the amp output, and the negative side of both to the negative terminal in parallel (remember to double-check your extension speaker jack is wired in parallel- it usually is). We know the total impedance will go down, but how do we calculate the actual load? The formula for the total load of multiple cabinets in parallel is:

Total impedance (Zt) = (Za x Zb) / (Za + Zb)
(Where Za and Zb equal the impedance of each cabinet wired in parallel).

It almost sounds like you might have to fire up that calculator app on your smart phone, and indeed you might at some point. But fortunately most commercially made extension speakers are standard impedances of 16 ohm, 8 ohm or 4 ohm, so a lot of the time you are connecting two cabinets of the same impedance together. When the loads are the same the formula simplifies itself and you only need to divide the impedance of the cabinets by the number you are connecting in parallel:

Zt = Zc / Tc
(Where Zc is the impedance of the cabs, and Tc is the number of cabs wired in parallel).

If you want to add a Carvin Audio 212E cabinet to your Carvin Audio Belair combo, you have an internal load (of the amp's built in speaker pair) which matches the impedance of the extension cabinet (both are 8 ohm). Your total load is 4 ohms (8 ohm / 2 cabinets). Using a pair of 4 ohm cabinets like the BR410 with your BX700 bass amp head yields 2 ohm (4 ohm / 2 cabinets = 2 ohm). Sometimes you will encounter a 4x12 cabinet for guitar wired to 16 ohm, and two of those in parallel will have a total load of 8 ohm.

Where does the series-wired circuit come into play?

In all of our former examples, we used self-contained speaker cabinets and did our calculations based on the impedance rating of the entire cabinet. It would be impractical to daisy-chain (parallel) multiple individual speakers. While a very small number of amps offer series-wired extension jacks, series-wiring is almost always used within an individual cabinet (see note below). It is pretty common for the musician to want cabinets with two to four speakers in them, so the designer might wire a pair of 8 ohm speakers in series inside the cabinet to get a convenient total load of 16 ohm. By using parallel wiring to lower the total load, and series wiring to increase it, you can achieve some control over the total output impedance. This is especially useful with multiple speakers where the total load in parallel is less than the minimum load-rating of the amplifier. Some 4x12 cabinets for guitar (like the Carvin Audio VX412T), utilize two pairs of 16 ohm speakers wired in parallel to offer stereo 8 ohm inputs, but also have a switch that puts both pairs in series so you can use the cabinet in mono at 16 ohm.

VX412T Guitar Cabinet

The VX412T offers stereo 8 ohm inputs or a mono 16 ohm input

The formula for speakers wired in series is simple:

 Zt = Za + Zb
Where Za and Zb are any number of speakers. You just add up the total impedance of all the speakers in series.

Note: To series-wire your cabinet, the positive terminal of the first speaker attaches to the positive side of the output amp, but the negative terminal is connected to the positive terminal of the next speaker in line, which in turn has its negative terminal attached to the positive terminal of the speaker after that, etc., until the last speaker has the negative terminal attached to the negative side of the amp.

Being familiar with how to calculate your total impedance can help you get the most out of your equipment, and can also help you avoid causing damage to your gear! Every amplifier has a minimum rating that you cannot drop below. Guitar amps usually have 4 ohm minimum output-ratings and bass amps can often support a 2 ohm total load. It is important to check the label on the back of the amp or look up the specs, so you know for certain. Less than the minimum load can essentially short your amplifier's output and can damage your power amp. And knowing how different cabinets will work together can be useful in getting the most out of your speaker system, so you always sound your best.
  • Share:


Also in Guitar / Bass Amplifier Info & Education

Harnessing the Power of Feedback
Harnessing the Power of Feedback

September 15, 2023

Feedback may not be something FOH engineers want to deal with, but it’s a well of creative potential for guitarists. It’s not a new concept – guitarists have been tapping that well since the amp was invented, but it’s still a great way to transcend boundaries, evoke new textures, create atmospheres, and find new tone – without any new tools.

Read More

Advanced Guitar Effects for the Experimental Guitarist
Advanced Guitar Effects for the Experimental Guitarist

August 18, 2023

It’s not like the guitar is ever boring. But sometimes you just want to branch out and see what else you can accomplish. This is true if you’re in a noise band or hyper-experimental act, but it’s also true if you’re in a straight-ahead rock band looking to add a few crazy moments to your show or record. So, let’s look at a few advanced effects you can try for that experimental vibe.

Read More

5 Effects Every Guitarist Should Try
5 Effects Every Guitarist Should Try

July 31, 2023

We all know pedals are almost as much a part of a guitarist’s essentials as the guitar itself – even more so than amp cabinets, probably. And there are some pedals every guitarist should have in their arsenal as a default. Stuff like a tuner, overdrive, and chorus. But there’s also a world of creativity out there, and there are a few pedals we think every guitarist should try at least once. Here are the top five.

Read More

Sign up to get the latest on sales, new releases and more…

Contact Us    858-751-4884
support@carvinaudio.com

International Sales

Warranty and Trial Period

Shipping

Manuals

NoFraud Frequently Asked Questions

Thiele/Small Parameters

Schematics

Firmware Download

Become a Dealer

About Us

"Make a joyful noise unto the Lord all of the earth; make a loud noise and rejoice and sing praises. Sing to the Lord with the harp and the voice of the psalm." - Psalm 98:4-5

© 2023 Carvin Audio. Carvin Corp.
POS and Ecommerce by Shopify

American Express Apple Pay Diners Club Discover Google Pay Mastercard PayPal Shop Pay Venmo Visa