How to Measure and Test IEM Performance


How to Measure and Test IEM Performance 

BQEYZ IEM CollectionIf you have no experience with IEMs, then purchasing your first pair can be a very daunting test. There are lots of concepts that you need to learn, and there are so many brands to choose from. But the truth is, choosing a pair does not need to be complicated. 

All you need to learn is a few core audio concepts that will help you determine which pair best suits your needs. Regardless if you are just a newbie in the hobby or if you are a more experienced user who is looking to upgrade, you should learn a few tips and tricks in this guide. And as a bonus, we will also be teaching you certain tests that will help you determine if your IEMs are defective in case you are buying a second-hand unit. 

What are In-ear Monitors 

Before we dwell deeper into this topic, let us first define what In-ear monitors are. In-ear monitors/IEM are devices used mostly by musicians, music producers, and audiophiles to listen to music. This device helps them hear themselves and replaces traditional wedge monitors; hence whey they are called In-Ear Monitors. 

The modern CIEM (Custom IEM) was first developed by Alex Van Halen’s (Drummer of the legendary rock band, Van Halen) drum tech Jerry Harvey who later founded his own company JH Audio. Their innovation was so revolutionary that it completely changed the game for musicians and audio professionals. This concept gave birth to Ultimate Ears as well as countless other brands. 

BGVP VG4 and UE900s (Image Credit: Stephen Menor/WIE)

However, IEMs are not only for musicians. They are also now being manufactured for casual music listening and come in many different flavors.

We have reviewed lots of IEMs on our website, and we highly urge you to check them out. 

Why do we need to test In-ear Monitors?

There are two major reasons why we need to test in-ear monitors. The first one is to know whether or not they fit our needs, and the second one is to test for any defects. 

Different IEMs have different sound signatures. So before purchasing a pair, you need to know if you will like them. Enthusiasts commonly refer to this process as auditioning. 

Also, if you are a performer, your IEMs must produce a specific sound that matches your instrument. Drummers want to hear their kick drum, cymbals, and snare drum; vocalists need to hear their voice clearly, etc. 

Additionally, knowing how to properly test IEMs will help you determine if your IEMs have any issues. IEMs can have factory defects or can fail over time. Diagnosing the issue can help you find the quickest solution to fix your IEMs.

How To Audition Your IEMs  

IEM review sample collection

Determine Sound Signature  

Every person has a different taste in music. Luckily there are also different kinds of sound signatures to match your style. The most common sound signatures for include Flat, V-shaped, Bass Heavy, Warm, and Bright.  

Flat Signature 

When referring to the Flat sound signature, all the frequencies are equal. This signature achieves a natural and realistic sound. This may seem to have a boring sound, but this is what professional sound producers need to properly mix the music that they make. 


The V-shaped signature emphasizes the bass and high frequencies. The midrange is usually recessed in this kind of signature. This sound signature gives a fun listening experience and is a good fit for modern genres with high energy, such as pop and hip hop. 

Bass Heavy

As its name suggests, the bass-heavy signature puts a lot of emphasis on the low frequencies. This creates a rumbling sound that is perfect for high-energy genres such as EDM. The major downside is that the extra bass can distort and down out other elements in the mix. 


The Warm/Smooth signature places emphasis on the lower mid and bass frequencies, which helps achieve a more relaxing sound. Highs are usually rolled off to prevent them from sounding too harsh. 

Bright Signature 

The bright sound signature is the complete opposite of the warm signature. The upper mids and highs are more pronounced. This gives the overall sound more detail but can sound harsh and fatiguing to most users. This signature is hard to achieve and is mostly seen in higher-end IEMs. 

Determining Technicalities and Detail Retrieval 

tin t5 compared to ikko oh1 meteor
tin t5 and ikko oh1 

The technicalities of an IEM usually cannot be quantified or represented in graphs. Therefore, the best way to determine how well an IEM performs is if you compare it side by side with another IEM in the same price tier or a more expensive IEM. If you are testing IEMs in a shop, we highly advise requesting a reference model to gauge how well your IEMs perform.  

Frequency Response

The frequency response tells the capability of your listening device to respond to all the audible frequencies. Most modern IEMs can typically produce frequencies from 20Hz – 20,000Hz. You can learn more about this topic in our dedicated frequency response article. 

One useful concept that you can use to help test your IEMs is the frequency response graph. This graph gives a visual representation of how well a certain IEM deals with a certain frequency. This will also help you visualize what sound signatures look like. 

Using Measuring Tools 

There are measuring tools that can help in testing your In-ear monitors. The most accessible tool is the MiniDSP Ears. This tool has a pair of dummy ears with 2 specialized microphones inside. This can be used as a binaural microphone that is usually used in ASMR videos/voice records. 

ssp vs ssr shell
Moondrop SSP and SSR 

These kinds of tools can record the sound of your IEMs and can generate a graph that will help you determine the exact sound signature of your IEM. This tool is not a requirement for all enthusiasts and professionals but can be useful if you want to learn more about your IEMs or if you are troubleshooting any issues. 

Testing for Defects 

Left and Right Driver Imbalance

One issue that IEMs may face is driver imbalance. This happens when the drivers of the left and right earpiece do not exactly match. You can easily determine if your IEMs have this problem if one of the earpieces has a lower volume. 

Additionally, one of the earpieces may have trouble producing certain frequencies. This issue can happen when drivers are poorly matched from the factory or if one of the drivers fails over time. 

To accurately determine this defect, you can measure your IEM with a driver matching test. This test sends an equal level of frequency on both sides of your in-ear monitor. The drivers inside should respond equally.

Frequency Sweep 

Using a tool that has a frequency sweep feature is another great way of troubleshooting your IEMs. This test will basically generate sounds across the frequency spectrum. Make sure to pay attention if your IEM has trouble reproducing certain frequencies. 

There are lots of tools that are available online to test your IEMs. This is the free online tool that we use for quick tests on our IEMs. 

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