Choosing the right speakers for your amplifier can be a confusing and long-winded process. When it comes to technical details and electrical specifics, it can be hard to know exactly what is right for your setup and your sound.
In this article, I’ll try to distill the technical jargon down into easy-to-understand language to help you make the right choice for your amp.
Let’s get into it!
Table of Contents
Ohms, Watts, and Impedance
To get anything close to a definitive answer to the title question, let’s first wrap our heads around some of this terminology.
Impedance
Let’s start with impedance since that is what is actually being measured in ohms when you see it on the back of your amp or speakers.
Impedance is the measure of electrical resistance in an alternating current (AC). When dealing with speakers and amps, you can work out the impedance by looking for the ohm symbol.
Ohms
An ohm is the unit of measurement for impedance. They are represented by the greek symbol for Omega, which looks like this: Ω. On the back of your amp head or speaker cabinet, you’ll see that symbol preceded by either 4, 8, or 16.
Amps are designed to work at a certain level of resistance, or impedance, but most have different inputs or switches allowing you to choose the resistance depending on what you’re plugging in.
Wattage
Wattage is a simple measure of how much electrical power an amp has, and how much electrical power a speaker needs. As a general rule of thumb, you want to try and match wattage and ohms wherever possible.
Safe Usage
When it comes to tube amplifiers, and how to match them with the right speakers, there are a couple of things you want to bear in mind:
- Never turn on a tube amp unless the speakers are connected
- Your amp should never be set to a higher ohm resistance than your speakers – this can quite literally blow your speakers!
- Match ohms and watts wherever possible.
- If you can’t match them, use speakers with a higher ohm resistance than the amp. E.g., an 8-ohm speaker with a 4-ohm amp.
Which Speakers Are Best for You?
Now you might be wondering what all of that means in real, practical terms. So you can do the math and work out which speakers should go with which amp – so what? How does it sound?
Well, as I mentioned before, you always want to try and match the impedance of your gear. This will produce the most ‘true’ sound, i.e., as close to how the manufacturers intended as possible.
The main physical difference between 8-ohm speakers and 16-ohm speakers is the number of voice-coil wire turns in the magnetic gap. This sounds very technical, but it basically means that different speakers are built for different impedances, and in turn use different materials and build specifications.
This in turn will make minor differences to the tone. Here’s a quick guide to what kind of sounds you’ll be producing.
Note: these tonal variations are often difficult to notice, even to a seasoned professional, and vary between makes and models of amps and speakers. What follows is more of a general overview of what you may expect to hear from different speakers
8-Ohm Speakers
8-ohm speakers have been said to have a ‘heavier’ and ‘less precise’ sound overall.
When mismatched with a 16-ohm amp (through a supporting OT [output transformer]), players have noticed a subdued tone, with an overall darker sound than when properly matched.
Many claim the mid-range frequencies are more apparent in 8-ohm speakers, but without detracting from the ‘fullness’ of the overall sound.
16-Ohm Speakers
Claims that 16-ohm speakers are more dynamic largely stem from their use with a 16-ohm amp head. The tonal benefits come more from the ideal matching of impedance than from the speaker resistance in ohms.
When used with a properly matched setup, 16-ohm speakers have been said to sound brighter, and present a full and dynamic range.
This is the main claim of many musicians and even some manufacturers; that the more ohms, the brighter the sound.
Final Thoughts
When it comes to impedance, it’s not so much about what you’ve got but what you do with it. Matching ohm-values is important, not only for not blowing up your speakers, but for achieving the best possible tone too.
While some guitarists will claim that different impedances and different loads will affect the tonal output of the amp, and that you should select a speaker based on its resistance in ohms, others claim the opposite.
In reality, we can see that the thing most likely to affect your tone is the matching (or mismatching) of speakers with amps. So before you spend your money on 16-ohm speakers because they’re supposed to sound brighter, check they’re compatible with your amp head first!
……..So before you spend your money on 16-ohm speakers because they’re supposed to sound brighter, check they’re compatible with your amp head first!
Hello James, you can always pour the water (current) into a bigger pot, but never the other way around. Its the same way with amps and speakers. 16 ohm speakers will be “compatible” with any typical amp. Lower into higher = ok. Higher into lower lets out the magic smoke . Cheers