Ask The Experts-MrSpeakers.com
What happens if someone who's passionate about audio creates their own headphones?
MrSpeakers was founded by Dan Clark, an electrical engineer who has been working in and around the high-end audio market for more than twenty years. Dan’s experience includes working in high-end retail, designing amplifiers and electronics for personal use, and designing commercial and custom loudspeaker solutions, including the highly-regarded and award winning Platinum Audio speakers from the late 1990’s. Dan has a particular fondness for Isobaric subwoofers.
So without further delay, let's get into the questions.
Passive or active sound canceling, or does it even matter?
Passive noise reduction uses the headphone’s cup, pad and other parts to keep sound from reaching the ear canal, while active noise cancellation typically uses a microphone to capture external noise then injects an “opposite” (out of phase) signal into the music to cancel out the noise at the ear.
In practice, passive noise blocking doesn’t affect the audio signal as there are no electronics, though the degree of isolation is very dependent on the construction of the headphone and can range from barely any blocking to almost as much as noise cancelling.
Active noise cancelling is a more complex system and while it may deliver better isolation from noise (especially at lower frequencies) as it’s directly manipulating the audio signal it is more prone to creating distortion and other artifacts that degrade the sound quality.Passive sound cancelling is typically most effective at voice frequencies and higher, while active noise cancelling is often most effective at the lower frequencies. On a practical note, this means that passive noise blocking, when well implemented, will be more effective at blocking ventilation system noise, PA announcements and crying babies while active noise cancellation is more effective at blocking rumble.
As a very frequent traveler, I’ve found rumble doesn’t bother me but constant announcements and loud passengers do, so all other things being equal for my own use I prefer passive noise blocking to active noise cancelling simply because it is more effective at eliminating the noises that disturb me and because it doesn’t degrade the sound quality. This has obviously manifested in our designs, which offer among the highest levels of noise-blocking Innerfidelity has measured in closed-back headphones.
What's the deal with "open back" headphones? Why would you use them?
Open back headphones have no “cup” or enclosure behind the audio driver while a closed-back headphone has a cup that is sealed or partially sealed behind the driver. The benefit of a cup is isolation and improved ability to use the headphones without being disturbed by or disturbing others. However, the downside of closed back headphones is typically that the headphones will sound more congested and closed-in, with a less detailed presentation and a smaller soundstage and a “cup” sound (place your hands over your hears, you can hear the tone of noises changes when you put a cup over your ear). A simple way to think of the effect of a closed cup is that there is a lot of acoustic energy being put into the cup which then interacts with the driver, and this stored energy can smear the sound and cause elimination of details.An open cup doesn’t store energy behind the driver, it just dissipates into space. For this reason, many headphone enthusiasts prefer open headphones because they tend to sound more spacious and detailed. That said, we have built something of a specialty making closed-back headphones that sound like open headphones. We’ve done so because many people only want to own one good headphone and since closed back headphones are more versatile, having a closed headphone with open-back performance is something of a “unicorn” product that allows users to have both excellent isolation yet delivers an open-sounding detailed and spacious headphone experience.
What are the top resources that got you to where you are in your audio knowledge? Outside of college, of course.
In many ways this is a very difficult question to answer.
First, my real introduction to headphone design and tuning came from the Head-Fi Fostex T50 modification thread where dozens of enthusiasts get together to modify off the shelf headphones.
It inspired me to start modifying headphones and was a wonderful introduction to different ways to modifying the sound of headphones. This helped me appreciate many of the subtle ways designing headphones differed from designing loudspeakers. There were many users on the thread whose work inspired me to get started and to get better, including Smeggy, BlueMonkeyFlyer and others.
Once I made the decision to go commercial with my work, I turned toward more rigorous research such as reading old patent filings and poring over audio, acoustics and engineering textbooks, trade publications, etc.
But of all the things that have been most important to me is simply listening to the positive and negative feedback of customers and reviewers with an open mind. Headphones are uniquely personal devices, and by paying careful attention to user feedback, I can broaden my design process to incorporate other people’s perspectives on how to assess and analyze sound.Beyond that is our primary experimentation and research where we try to understand the effects of the system on people’s perception of sound quality.
I’ve been working on headphones for seven years now, and there’s still so much to learn about how people perceive personal audio, and what factors they weigh to determine “good” and “bad,” or “fun” vs “audiophile.” Clearly audio has a continuum of variables that affect perception of sound quality.