Trying to get those tweeters under control? It can be a frustrating mess full of complicated math and wasted time & money.
Not to worry, though! I’ve designed & built my own tweeter volume circuits many times and I’ll show you how too.
In this article, I’ll show you how to reduce tweeter volume with clear info and easy-to-follow steps.
Here’s what I’ll cover:
- How tweeter attenuation works & what options you have
- How to properly reduce tweeter volume without affecting speaker crossover operation & sound
- Tweeter resistor volume diagrams & resistor value table – no math needed!
- Choosing the right resistor types, power ratings, and values
What is tweeter attenuation?
Diagram showing how tweeter attenuation (tweeter volume reduction) works to bring the tweeter volume down to a level better matching other speakers like midrange speakers. A tweeter resistor network, sometimes called an L-pad, can be used to reduce the volume & power a tweeter receives.
Tweeter attenuation is the reduction of voltage & power to a tweeter to decrease its volume output. This is usually done with a resistor network with values chosen to match the expected load of a stereo, amplifier, or speaker crossover.
In this simple example, we use a single series resistor to drop the voltage seen by a tweeter. Once we figure out the resistor value needed for a given volume reduction in decibels (dB), we can add it in series to reduce the power and consequently the power the tweeter receives. This causes the volume to be lower.
For speaker systems, tweeters often are more efficient (have a higher decibel output) than other speakers. In this case, there’s a mismatch often described as being “too bright.” For example, tweeters that are mismatched to midrange or woofer full-range speakers may seem very harsh & the music will sound unnatural.
Because tweeters are smaller and work slightly differently than larger speakers like midrange or woofers, it’s not unusual for them to be too “bright” sounding.
Speaker sensitivity explained
Speakers are usually given an efficiency rating by the manufacturer which is described in decibels (dB) of volume at 1 watt of power for comparison purposes.
For example, a midrange speaker may typically be about 87dB/W while it’s not unusual to see a tweeter with 92dB/W efficiency. That’s a difference of 5 dB, and enough that your ears can hear the difference.
This means the treble frequencies (upper range of sound frequencies) in music can be overbearing and annoying, causing listener fatigue – not just sounding bad!
To correct this, we can use a tweeter attenuation circuit with resistors to reduce the decibel output of the tweeters, matching them to the other speakers and improving the sound.
Can’t you just use an equalizer or treble setting?
Tweeter output can be really hard to adjust with some equalizers and nearly impossible to correct with most treble levels in amps or stereos. For that reason, a better way is to use a tweeter attenuation solution.
To make matters worse, while a good equalizer (EQ) can help by letting you reduce tweeter volume across its output range, many treble controls in car or home stereos can only adjust a very limited range of sound and won’t fix the entire range of tweeter volume.
Not only that but if there’s a really big difference in sound levels between the speakers, the EQ or treble control might not have enough adjustment anyway and you’ll never get it quite right.
Good equalizers aren’t cheap and they take time to set up properly
While it’s true that a very good 31 band equalizer gives you a lot of adjustment range, not many have those handy and they can be expensive to buy. It also takes a lot of time to adjust a complex equalizer.
You’ll also need a lot of time & effort for trial and error if you’re really adjusting your sound the right way. Some people use a calibrated microphone & measurement software to tune a sound system for best results – and none of that is cheap.
It’s much easier to just reduce the tweeter volume across its entire sound range instead.
Series resistors vs L-pads for tweeter volume
Resistor diagrams shown: Total resistance values for 8 & 4 ohm car & home stereos with a -3dB tweeter attenuation example. Series resistors are more simple but can’t be used in as many applications, while L-pad (series-parallel) networks work in any situation.
It’s easy enough to use a single resistor in series with a car or home audio tweeter for getting your tweeter volume levels under control. The problem is that without using an L-pad circuit, your amplifier or stereo will see a different value of speaker load for the tweeter side.
That’s not a problem if you’re directly driving a speaker with no inline speaker crossover, as there’s nothing to be affected by a higher speaker impedance (Ohms load). The problem comes when you add a speaker crossover – and that’s almost always the case when using tweeters and 2-way speaker systems.
Speaker crossovers are designed to work with a fixed speaker resistance. Change that, and you’ll mess up the crossover frequencies and the sound, too. Not what we want at all!
L-pads let you keep your sound AND control your tweeters
But how can we add resistors to drop tweeter volume but still keep the crossover working right? The answer is using an L-pad resistor network.
L-pad resistor networks are preferred over just using a series resistor because the total speaker impedance (Ohms) will be the same as what the amplifier, stereo, or crossover expects to sees. These networks use a series and parallel resistor design that add up to a total resistance that’s the same as the tweeter.
They’re a bit more complicated, though. You have to do more advanced math & algebra to figure out the resistors needed based on the decibel amount you’d like to reduce the tweeter by. For example, an L-pad resistor calculator like this can let you do it if you don’t mind the complicated stuff.
Keep reading, however, as I’ll show you an easier way.
Using an L-pad for tweeter volume
And L-pad is a ready-made part that lets you easily reduce tweeter volume. With it you can tailor the tweeter level to your liking instead of using fixed decibel levels like with a resistor network.
L-pads are an affordable and really simple way to reduce tweeter volume. An adjustable speaker L-pad is simply an adjustable resistor network version like the fixed value ones I’ll explain later.
Unlike fixed resistors, they’re designed to let you adjust the tweeter level over a range as they use potentiometers which are simply adjustable resistors. As the output is adjusted the total resistance (impedance, as it’s called for speakers) that the stereo or amplifiers see are kept the same. That’s nearly always 8 ohms.
That way if you’re using speaker crossovers, which are designed for a specific speaker Ohms load, the sound won’t be affected – only the volume. As you decrease the tweeter volume output the internal resistance is increased and less voltage reaches the tweeter, causing the volume to drop.
Things to know before buying an L-pad
Some models are single-channel and you’ll need one for each tweeter while stereo models let you control 2 tweeters at once. They’re also available in different power ratings as well.
However, while they’re a great solution, L-pads are nearly always only available for 8 ohm home stereo tweeters, not 4 ohm car tweeters.
How to wire a tweeter L pad
Tweeter L-pads are almost always connected the same way but always double-check your instructions & labels if provided. To connect a tweeter to an L-pad you’ll do the following:
- Connect the tweeter positive wire to the L-pad tweeter output (+) terminal
- Connect the tweeter negative wire to the L-pad common ground (-) terminal
- Connect the amp/crossover positive output to the L-pad positive input terminal
- Connect the L-pad ground terminal to the negative amp or crossover terminal
The reason why it’s nearly always connected the same way is that most L-pads are designed the same. The details (like wiring pins or terminals) may be a little different, but normally that’s the only difference.
Some models require soldering while others offer a screw terminal that makes the work easier. In either case, always be sure to use an L-pad that has enough power rating for the speaker or tweeter you’re using it with.
A good rule of thumb is to pick one with at least 1/2 of the power ratings (Watts) of the tweeter you’re using. Always use the RMS power rating, not the “peak” or “maximum” as those are misleading and not what you need.
How to reduce tweeter volume with resistors (steps & diagram)
It’s pretty easy to reduce tweeter volume with resistors. To do so, use the instructions in the diagram I’ve provided above. There are only a few steps you’ll need:
- Find the resistors you need based on the tweeter impedance (Ohms) and the tweeter volume, in decibels, you want to decrease. Use my provided chart (easy) to look up the series & parallel or calculate them yourself (much harder!)
- Buy power resistors needed. Resistors can be combined using different values in order to help you make the best of limited options. I recommend using 25W minimum resistors, although you can get by with 15W each if you’re using multiple resistors.
- Connect the resistors using a reliable connection as shown in the diagram. I recommend using crimp connectors or solder. To prevent short circuits, wrap exposed resistor leads with electrical or use heat shrink tubing.
How big of a resistor do you need with a tweeter?
Examples of power resistors that work fine for tweeter attenuation use. You’ll usually find the wire-wound type but also sometimes the metal chassis form, too. Both work great and can handle much more power than standard electronic use resistors.
Tweeters need resistors with sufficient power ratings in order to handle the heat they’ll build up since they reduce volume by “blocking” (reducing) power sent to the tweeter.
As a general rule, if using a single resistor for the series or parallel part of an L-pad circuit, use one at least 1/2 the power rating of the tweeter or power output of your amp you plan to use. For average use, a 25W resistor works well.
If you’re combining resistors in order to get the resistance you need, you could also use 15W rated parts. Those are commonly found when shopping too.
Standard resistors like this are used for electronics and aren’t ok for using with tweeters. They’re not available in power rating styles that can handle audio power levels. Most are only 1/8W to 1/2W at most.
Don’t use standard electronics resistors, however, as they’re not designed to handle the power seen from an amplifier for speaker systems. It’s possible for them to burn up due to the extreme heat they can build up.
Which wire does the resistor go to on a tweeter?
Resistors aren’t polarized – either wire (lead) can go towards the tweeter, so don’t worry. That’s different from components like diodes and LEDs which have a single direction of current flow and have to be wired a specific way.
Where to buy the parts + keeping costs low
There are some great places to buy audio resistors online if you’re located in the United States. If you’re not, you should still be able to find suppliers of electronic components including audio power resistors. You’ll get the best deal and keep a budget spending limit if you shop carefully.
Unfortunately, the days of being able to go down to your local Radio Shack and buy parts are long gone, at least for most of us here in the USA. To make matters worse, Fry’s Electronics, an electronics retailer, seems to be in terrible business condition and closing stores, in fact.
(Note that you might be able to find enough resistors at Fry’s or another local retailer if you’re lucky).
Normally, however, unless it’s urgent I buy muy tweeter resistors and resistors for building speaker crossovers from one of a few places:
- PartsExpress.com – A great company with a nice selection of affordable parts, speakers, audio electronics, and much more. Recommended! (I’ve bought tweeter resistors there several times)
- Ebay – Not always great, but for typical resistor values it’s possible to get a good deal on a multi-pack set of resistors from a USA supplier.
- Amazon.com – Ok, depending on the supplier. Power resistors at Amazon are affordable and some but not all are USA-based sellers.
In all cases, I would recommend starting with PartsExpress.com’s resistor selection here.
One of my UK readers mentioned he found some for his project from BlueAran.co.uk.
How much do tweeter resistors cost?
You can expect to pay anywhere from around $.80 each to about $1 each when priced affordably, or around $4-$5 for a pair or for 4 in some cases.
25W resistors do cost slightly more than their lower power counterparts, but not by too much. Usually, though, they’re either sold in singles or pairs while it can be easier to find smaller power rated ones in sets of 4 or 5.
Where to use tweeter volume resistors with crossovers
When using a resistor network to reduce tweeter volume & crossovers are used, it’s super-important to use them in the right place.
As I mentioned earlier, it’s very important to use tweeter resistor networks (L-pads) in the right place.
Crossovers are designed to work based off of the speaker load connected to them, and because of this, changing that amount can have a big impact on how they work (and how your speakers sound, too).
For example, if you’re using a car speaker crossover designed for 4 ohm speakers and insert a single resistor (let’s say a 4 ohm, for example) to reduce tweeter volume, the crossover frequency will change radically. It would go up 2x as high in fact in this example.
L-pads & L-pad resistor networks take this into account and create the same resistance so the crossover can work as expected. However, it’s also important to use it properly.
Remember that you should always use an L-pad or resistor network between the speaker crossover and the tweeter.
Additional reading + if you have questions
Want to learn more about speaker topics? Here are some other great articles I’ve created to help:
- Find out if speaker wire makes a difference for sound quality.
- Love bass in your car? Here’s how to wire dual voice coil subwoofers properly.
- Learn more about what size speaker wire you really need.
Have questions about tweeters and reducing their volume? Feel free to leave a comment below or send me a message.