Review: Sennheiser IE 100 PRO Wireless – Freedom and Professionalism Combined!

The IE 100 PRO Wireless is well protected with foam in the box.
The IE 100 PRO Wireless is well protected with foam in the box.

Sennheiser specifically created the 2-in-1 combo package of the powerful IE 100 PRO IEMs plus a Bluetooth module to address the different needs of the audiophile community.

Thank you, Wenbin from Sennheiser Asia, for sending me the Sennheiser IE 100 PRO Wireless IEMs in exchange for my honest review and opinion.

The new driver in the Sennheiser IE 100 PRO is specifically created for professional use, such as on a live stage. The IE 100 PRO can deliver perfect audio clarity for artists in live sessions.

According to Sennheiser, the IE 100 PRO are preferred by musicians and DJs because of their outstanding sound and high wearing comfort. Not only restricted to live sessions but the IE 100 PRO are also designed for on-the-go production or as a daily companion.

With the integrated Bluetooth module, the IEMs transform into convenient daily companions like your smartphone or computer. IE 100 PRO Wireless can handle phone conversations, webcasts, and conference calls with the built-in mic, which is particularly useful for those working from home during the COVID-19 pandemic.

Sennheiser specifically created this 2-in-1 combo package - the powerful IE 100 PRO IEMs plus Bluetooth module for wireless use with mobile devices to address different needs from the audiophile community.
Bottom Line

The Sennheiser IE 100 PRO are a good pair of IEMs that serve different purposes, especially with the wireless Bluetooth Connector. However, the bright sound signature means the IE 100 PRO are a no-no for those who are bothered by forward treble. The IE 400 PRO or even the IE 40 PRO will be better candidates if you fall into that group of users.

What We Like
  • Excellent build quality
  • Precise bass response
  • Good isolation
  • Transparent and airy mids
  • Well extended highs
  • High-quality wireless IEM cable
  • Stable connectivity
  • Low latency supported
What We Don't Like
  • Rare Pentaconn Ear connector
  • Fatiguing treble
  • Lack of sub-bass depth

Company Overview

Founded by electrical engineer Prof. Dr. Fritz Sennheiser in 1945, Sennheiser’s goal is to shape the audio world of the future now. This vision statement explains what they hope to accomplish, with their history, their culture of innovation, and their desire for excellence serving as the foundation.

Sennheiser has consistently established trends in the audio business. Right up to the current day, their inventive creativity, curiosity, and enthusiasm have resulted in enormous success. Whether clients are musicians, DJs, pilots, scientists, sound technicians, or demanding music fans, the Sennheiser brand is synonymous with premium goods, unrivaled sound quality, and an undistorted listening experience.

Technical Specifications

  • Form: IEM
  • Drivers: 1 x dynamic driver
  • Impedance (Ohm): 20 Ohms
  • Sensitivity (dB): 115 dB (1 kHz / 1 Vrms)
  • Frequency Response (Hz): 20 Hz – 18 kHz
  • Removable Cable: Y
  • Source Jack: 3.5mm
  • Cup/Shell Jack: Pentaconn Ear
  • Bluetooth Audio Codec: SBC, aptX®, aptX LL®, AAC
  • Battery Life (hrs): 10 hrs music playback via SBC
  • True Wireless: N
  • Bluetooth Version: 5.0
  • Mic: Y (on Bluetooth module only)

Packaging

The unboxing experience for the IE 100 PRO Wireless is pleasant. They come in a box with a similar design as the others in the IE series, such as the IE 400 PRO. The Sennheiser branding, plus the model’s name and photo are printed on the outer paper sleeve. On the back of the box, the unique selling points and technical specifications are listed.

In the box

  • IE 100 PRO (black, clear, or red colors)
  • Bluetooth connector
  • Black cable for IE 100 PRO
  • USB-A to USB-C cable
  • Soft pouch
  • Cleaning tool
  • Foam and silicone ear adapters
  • Quick guide
  • Safety guide
  • Compliance sheet
The IE 100 PRO wireless come in a box with a similar design as other IEMs in the IE series, such as IE 400 PRO.
The IE 100 PRO wireless come in a box with a similar design as other IEMs in the IE series, such as IE 400 PRO.
The IE 100 PRO Wireless is well protected with foam in the box.
The IE 100 PRO Wireless is well protected with foam in the box.
The soft pouch of the IE 100 PRO Wireless is light and pocket friendly.
The soft pouch of the IE 100 PRO Wireless is light and pocket friendly.

Cable

The IE 100 PRO Wireless come with 2 cables in the box – a cable for wired connection and a wireless IEM cable. The wired connection cable is the same as what you get with the IE 400 PRO.

The wired connection cable is covered with a black sleeve and terminated with a 3.5mm unbalanced jack. As described by Sennheiser, the cable is built with a unique internal cable duct (patent pending), making it suitable for stage usage.

The cable for a wired connection in the IE 100 PRO Wireless is the same as what you get with the IE 400 PRO.
The cable for a wired connection in the IE 100 PRO Wireless is the same as what you get with the IE 400 PRO.
The Y-split on the stock wired cable has a Sennheiser's logo engraved.
The Y-split on the stock wired cable has a Sennheiser’s logo engraved.
The stock cable is terminated with a 3.5mm unbalanced jack.
The stock cable is terminated with a 3.5mm unbalanced jack.

The sleeve is the same for the Bluetooth cable and the wired cable. There are two modules on each side of the cable – the right contains the controls while the left is for the battery or Bluetooth chip (I suspect). This design is good to balance the weight between the left and right sides of the cable.

The IE 100 PRO utilize Pentaconn Ear connectors.
The IE 100 PRO utilize Pentaconn Ear connectors.
The remote control is on the right side of the Bluetooth Connector wireless IEM cable.
The remote control is on the right side of the Bluetooth Connector wireless IEM cable.
There is another module on the left side of the Bluetooth Connector to balance the weight of the controller on the right.
There is another module on the left side of the Bluetooth Connector to balance the weight of the controller on the right.

Design

The IE 100 Pro’s exterior is made of plastic. I received the clear variant and through the nearly transparent shell, I can see the tidy driver and cable arrangement inside, which gives a premium appearance. Because of the material used, the IEMs are lightweight.

Through the nearly transparent shell, I can see the tidy driver and cable arrangement give it a premium appearance.
Through the nearly transparent shell, I can see the tidy driver and cable arrangement give it a premium appearance.

The detachable cable design is required for individuals working in the studio or on stage, as some will utilize a mono cable that connects to only one side of the IEMs. Besides that, the detachable cable design also enables Sennheiser to offer the wireless option with their Bluetooth cable.

The detachable connection is also advantageous for audiophiles, allowing for cable repair or even an upgrade. On the IE 100 Pro, Sennheiser employs the Pentaconn Ear connection, which was conceived and invented by Nippon Dics. This connector is not commonly used (like MMCX or 0.78mm 2-pin) so it may be somewhat difficult to find replacement cables.

On the IE 100 Pro, Sennheiser employs the Pentaconn Ear connection, which was conceived and invented by Nippon Dics.
On the IE 100 Pro, Sennheiser employs the Pentaconn Ear connection, which was conceived and invented by Nippon Dics.

The nozzle is one piece with the IEM shell. The IE 100 PRO Wireless have an acoustic damper in the nozzle’s bore, which acts as protection for the driver (preventing foreign material from entering the internal cavity of the IEMs) and as a passive acoustic filter. The length of the nozzle is relatively short. There is a lip on the nozzle to help it catch on the ear tips, improving ear tip rolling and retention.

The IE 100 PRO Wireless have an acoustic damper in the nozzle’s bore, which acts as protection for the driver (preventing foreign material from entering the internal cavity of the IEMs) and as a passive acoustic filter.
The IE 100 PRO Wireless have an acoustic damper in the nozzle’s bore, which acts as protection for the driver (preventing foreign material from entering the internal cavity of the IEMs) and as a passive acoustic filter.
The length of the nozzle is relatively short. There is a lip on the nozzle to help it catch on the ear tips.
The length of the nozzle is relatively short. There is a lip on the nozzle to help it catch on the ear tips.

Comfort

The shell is well-designed, with no pressure points that cause ear discomfort during extended listening sessions. The tiny housing fits comfortably in my ears and provides adequate isolation. Because of its small form factor, I feel the fit will be satisfactory for most individuals.

There is a tiny vent on the outside of the shell that helps to reduce driver flex. During the reviewing period, I did not experience any driver flex. The IE 100 Pro provides enough isolation and passive noise cancellation when I am traveling on public transportation.

Driver flex is when the driver bends due to air pressure against it. Usually, it occurs when you’re inserting the IEM into your ear, and air in the shell creates pressure to bend the driver.
There is a tiny vent on the outside of the shell that helps to reduce driver flex.
There is a tiny vent on the outside of the shell that helps to reduce driver flex.

Internals

The IE 100 PRO Wireless have a single dynamic driver configuration. Sennheiser specially designed the driver for a high-resolution and powerful monitoring sound. They claim it reduces acoustic stress factors through natural and distortion-free reproduction.

The Bluetooth cable is powered by Bluetooth version 5.0 to provide excellent connection stability and it supports SBC, aptX®, aptX LL®, AAC Bluetooth codecs.

I find the aptX LL® codec to be useful, especially during video playback, because the latency is low, and there is no delay between speech and visual.

Sennheiser IE 100 PRO Wireless Sound

The IE 100 PRO Wireless have a bright sound signature. I would class them as reference gear, and I use them for critical listening most of the time. For those who have lower treble tolerance, they might not be suitable for you. This pair of IEMs have the signature of a typical studio monitor, meaning an uncolored and transparent sound that is more suitable for critical listening rather than casual listening.

The IE 100 PRO’s soundstage is above average laterally but not vertically. They don’t have sufficient depth in the headroom. The entire presentation is open and spacious, neither too close nor too far away.

The gap between the listener and the performers is precisely measured, resulting in a comfortable listening experience. Individual instruments and voices are placed correctly. When you close your eyes, you can identify precisely where those instruments are, just like you would at a theater or performance.

The IE 100 PRO Wireless have a bright sound signature. I classify them as a reference gear, mainly suitable for critical listening.
The IE 100 PRO Wireless have a bright sound signature. I classify them as a reference gear, mainly suitable for critical listening.

Bass

The IE 100 PRO Wireless lacks the dramatic bass response of conventional dynamic driver-powered IEMs. The bass is lean and tight, resulting in accurate and precise performance, with rapid attacks and decays.

While they are not a pair of basshead-level IEMs, the sub-bass has a fair amount of extension. The sub-bass rumbles are audible, but I’d like to hear more extension to provide greater depth in the soundstage. The bass impact does not interfere with other frequencies. It’s like a nice shadow on the track – there yet unobtrusive.

The IE 100 PRO Wireless lacks the dramatic bass response of conventional dynamic driver-powered IEMs.
The IE 100 PRO Wireless lacks the dramatic bass response of conventional dynamic driver-powered IEMs.

Midrange

The presentation of the mids is transparent and open. The mids receive the least amount of color, resulting in the most natural portrayal. When listening to male vocals, the bright signature with lack of warmth makes them analytical. I prefer male vocals with thicker and richer bodies, which introduce emotion and liveliness.

The IE 100 PRO performs admirably with female vocals – they are delivered pleasantly and quickly. The overall presentation is not laggy in any way. The upper midsection is light and airy. In terms of total midrange placement, it is slightly ahead of the bass.

The layering of mids and bass improves the overall accuracy of the IE 100 PRO presentation.

The presentation of the mids is transparent and open. The mids receive the least amount of color, resulting in the most natural portrayal.
The presentation of the mids is transparent and open. The mids receive the least amount of color, resulting in the most natural portrayal.

Treble

I’ve tried various Sennheiser models, from the entry-level Momentum In-Ear to the top-of-the-line HD820. Sennheiser’s treble is always a weapon – clear, well-handled, distortion-free, and smooth. There are so many positive words I could use to describe it. The IE 100 PRO show the same characteristics as their predecessors without fail. The highs are particularly well-extended, resulting in high overall fidelity.

However, I found the IE 100 PRO to be harsh in the highs, and this is why I do not recommend the IE 100 PRO to those who have a lower tolerance for bright treble. They might cause fatigue after prolonged listening. A comfortable listening experience is traded off for sparkling and engaging treble, which is not everyone’s cup of tea.

I found the IE 100 PRO to be harsh in the highs. This harshness in the treble is why I do not recommend the IE 100 PRO to those who have lower treble tolerance.
I found the IE 100 PRO to be harsh in the highs. This harshness in the treble is why I do not recommend the IE 100 PRO to those who have lower treble tolerance.

Where to Buy

If you’d like to purchase a pair, you can buy them from Sennheiser’s official website.

Conclusion

The Sennheiser IE 100 PRO are a good pair of IEMs that serve different purposes, especially with the wireless Bluetooth Connector. However, the bright sound signature means the IE 100 PRO are a no-no for those who are bothered by forward treble. The IE 400 PRO or even the IE 40 PRO will be better candidates if you fall into that group of users.

Nevertheless, if you are like me, and prefer a bright signature, and are looking for a pair of IEMs for multipurpose usage, you should put the IE 100 PRO on your list.

The Sennheiser IE 100 PRO is a good pair of IEMs that serve different purposes, especially with the Bluetooth Connector.
The Sennheiser IE 100 PRO is a good pair of IEMs that serve different purposes, especially with the Bluetooth Connector.

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