Frequently Asked Questions


What is DM?

DM stands for Digital Modulation and is a generic name for modulation techniques that uses discrete signals to modulate a carrier wave. In comparison, FM and AM are analog techniques.The three main types of digital modulation are Frequency Shift Keying (FSK), Phase Shift Keying (PSK) and Amplitude Shift Keying (ASK).

DM eliminates transmission noise and offers improved robustness to signal interference. However, it is not uncommon for DM to introduce time delay due to the processing required. Comfort Audio’s SecureStream Technology (SST) is especially designed to avoid this.


Can Assistive Listening Devices Help Children Who Do Not Have Hearing Loss?

Studies from the U.S. and Denmark show that digital assistive listening devices are a great aid for students with dyslexia, autism, learning problems and concentration difficulties. More and more students have difficulty following traditional schooling because of concentration and learning difficulties. Often, these students get diagnosed with attention-deficit/hyperactivity disorder (ADHD), auditory processing disorder (APD), Dyslexia or other types of speech or writing difficulties.

Digital hearing products have proven to be good complements to other treatments in mitigating concentration difficulties. A substantially better learning environment is accomplished with the use of personal digital hearing products. Distracting background noise is markedly reduced, and the student can hear the teacher more clearly. It becomes easier to maintain concentration throughout an entire school day, which increases learning.

I performed a study of 20 normal-hearing children, ages 10-11, from two different school classes (Lejon, 2014). I used the Illinois Test of Psycholinguistic Abilities (ITPA), which comprises 12 subtests, measuring how well students can read, write and spell. One subtest focuses specifically on auditory sequencing and tests the effectiveness of a child’s short-term auditory memory.

My findings revealed that 13 out of 16 normal-hearing students were better able to absorb information and follow instructions when using digital hearing products than when listening on their own. The study was performed in a typical school environment; participants were equipped with Comfort Focus receiver and transmitter. The improvement was especially great among those children who struggled with concentration.

The most important observation was that students with poor results in school, often due to concentration difficulties, reached the level of knowledge expected for their age group. Students at an average knowledge level also reached higher levels compared to their peers.

From this study, we know that high-quality assistive listening devices, such as the Comfort Audio Comfort Focus, positively affects the normal auditory sequencing in children in a normal school environment, including those with other learning difficulties besides hearing loss.


Lejon, A. K. (April 2014). Comfort Focus and auditory sequencing.

For more information, please visit or the Comfort Audio Expo Page on AudiologyOnline.

As adults seem to stay in the workforce longer before retirement, how can we support our patients who are working longer and in varied communication situations in the workplace?

Hearing loss is a very common adult disability. According to Kochkin, 3 in 10 people over the age of 60 have hearing loss; 1 in 6 baby boomers and 1 in 14 Generation Xers already have hearing loss. Your concern about more individuals with hearing loss in the workplace is a valid one.

We at Comfort Audio often get the feeling that a hearing aid alone in many workplace situations is not enough. To prove that, we initiated a questionnaire to gather facts about hearing aids and cochlear implants alone versus hearing technology coupled with an assistive listening device, namely the Comfort Digisystem. Twenty-four of 64 individuals returned the questionnaire. There were five main situations that these respondents deemed most difficult when using their hearing aid or cochlear implant alone. Their perceived degree of difficulty in the same five situations was markedly less with the Digisystm

Hearing aids have been improving steadily over the last 10 years, but even what was big news in a hearing aid in the late 1990’s (e.g. noise cancellation, directional microphones) is now standard in most technologies. Even with advanced features, users are not completely satisfied with hearing aids in difficult listening environments. In situations that are crucial for a successful working experience (e.g. lectures, larger meetings, background noise, small group conversations, et cetera), users struggle with hearing aids alone, but do report better workplace outcomes when using assistive technology, such as the Comfort Audio Digisystem. Assistive technology is more readily available and may be an excellent choice for those who are working later in life.

Can you use the Comfort Digisystem for auditory processing or concentration problems?

Absolutely. The DH10 receiver is a great option for this, and we do have other options as well in our consumer line. While the DH10 is a neck loop receiver, you can also utilize it with a set of headphones or earbuds. You can adjust the volume so it does not get too loud, which is important for children with disorders that do not encompass hearing loss. You can use the DM05, DM10, or even the CD10 conference microphone.

A product specifically for auditory processing is the Comfort Audio Contego system, which is in our comfort line. It is distributed more as a direct-to-consumer product. Children can monitor their own voice and the teacher’s voice coming through the transmitter. Dr. Jeanane Ferre, an audiologist in Chicago who specializes in auditory processing, has recommended the Comfort Digisystems for students. She likes the Contego because children can monitor their own voice.

Can you help me select the best microphone option for the Comfort Digisystem for my student?

When team teaching using the Comfort Digisystem from Comfort Audio, what is the delay time of the companion mic to the receiver worn by a child?

The delay time is quite low because we use digital transmission. It takes less than 3 milliseconds, so there is essentially no noticeable delay. Because the signal is digital in to digital out, we do not have to convert signals back and forth, so we do not lose any transmission time.

Can you use the DM30 microphone with the other receivers?

Yes. Many patients use the DM30 with our ear-level receiver, the DT20, or our legacy product, the DT10. They are all still compatible. Our Digisystem can be utilized back and forth.

What is the transmission range from the Comfort Digisystem microphones to receivers?

When you are utilizing the full-range microphones, DM10 or DC10, the distance is 100 feet. When you are utilizing the very small DM05 to our ear-level receivers that do have a smaller antenna built inside, it is a 50-feet transmission range. Most transmission ranges are 100 feet, especially as you go from a transmitter to a receiver that has a larger internal antenna. Those ranges do depend on the interference that may exist inside the classroom, as well.

How many microphones can be added to a system?

You can use up to 12 different microphones with one Comfort Digisystem.

Why is the transmission not disturbed when you have so many microphones?

Because we are using digital SecureStream Technology, we can space out our channels so they are not overlapping. This is why the push-to-talk functionality works so well.

Which microphone would you recommend for multiple students wearing micro-receivers?

I would recommend using the DM10 microphone. This is a suitable option for multiple students in a classroom setting. The DM10 is a versatile microphone that transmits over a 100-feet range. This microphone gives you a 10-hour talk time to make it easily through the day.

These questions and answers were taken from the Comfort Audio course, Why DM/FM?

My receiver just makes a noise! What kind of a fault is it?

Noise from your receiver tends to be due to two factors in the main. Either you have interference on the channel you are using, or the units are not paired properly (see pairing below.) Try using a different channel or carry out pairing again.

My battery does not last as long as I would like it to. Is there anything I can do about that?

The best way of ensuring as long a life as possible from a Li-ion battery is to use it. Avoid leaving the battery in a discharged or fully charged state for long periods. If a product is not going to be used for a longer period of time, the battery should first be charged to around half (40%) capacity and then charged just a little at regular intervals to prevent so-called deep discharge, which can harm a battery. Batteries of lithium ion type do not have the so-called memory effect and do not have to be completely discharged as do NiCd batteries, for instance.

How do I pair my units?

Pairing of units can be done at any time using the pairing button or via the unit’s menu.