Headphones Research Articles

Simplified amplifier providing sharing of music with enhanced spatial presence through multiple headphone jacks

A personal listening device used in connection with the amplification of signals for enhancing the perceived quality and ambiance of sound heard by listener using stereo headphones or small speaker systems utilizes a difference signal that is cross-fed between stereo channels. The invention provides a perception of spatial presence in music sound when used with either stereo headphones or small speaker systems. The circuitry, wiring and packaging provide for multiple output jacks allowing for convenient sharing of the enhanced output signal from a personal listening device with other persons using headphones. The invention provides effects similar to stereo enhancement, surround sound, and psychoacoustic imagery in a small, inexpensive package for enhancing a user's audio experience.

Noise damping headset with a throat microphone

The invention relates to a noice damping headset (1) comprising at least one microphone and at least one ear phone (3) intended to be connected via electrical conduits, preferably wires (18), to a transmitter and a receiver (4), preferably a mobile telephone, a communication radio or the like for communication between persons. The microphone consists of throat microphone (5) for direct or indirect contact against the skin around a throat (6), the equipment mainly being sound tightening for sounds (11), coming from outside, from emerging into the throat microphone (5) and the ear phone (3) comprises a funnel-shape (7) for inserting the same into the auditory canal (8) of a person’s ear, the outer limiting surfaces (9) of the funnel-shape (7) being sound tightening against the walls (10) of the auditory canal (8), the sound (11) coming from outside being prevented from emerging into the auditory canal (8), whereby a communication between said persons can be held without being disturbed in a greateer extent of the sound (11) coming from outside.

Clip-style hearing protector

A hearing protection device (100) for a human ear. The device has an arm (106) that clips about the pinna. A plug member (102) caps or enters ear canal. The device is biased to provide some force against the plug member so that is stays in position during use. An optional handle may be provided to assist with temporarily pulling the plug member away from the ear canal or providing adjustment. The device may be adapted for use as an ear phone.

From toy to tool—advanced auralization procedure in daily design work.

Since more than 20 years simulation procedures are more and more common, but the auralization procedure is considered mainly as a toy. The reason for this relates partially to the efforts needed to get real auralized sound files. In a previous paper the authors reported about a method to produce high end auralization files. This method allows to use normal head phones to get the right spatial impression without in‐head localization. The main reason not to use an auralized sound impression in the daily design work is the time‐consuming procedure to calculate true impulse responses (IR) especially in large halls. In this paper new algorithms are reported to calculate IRs in multithread mode with one computer or better via a network with a set of CPUs working in parallel. So calculations in large halls maybe be reduced from 8–10 h with one CPU to 10–20 min with multicore computers. The paper explains the way from the model to high‐end auralized files. Some examples demonstrate the quality of these derived binaural files.

ノイズキャンセリングヘッドホン(<メカライフ特集>揺れる,揺らす)

ノイズキャンセリングヘッドホン(<メカライフ特集>揺れる,揺らす)

Utilization of filtering effects in stereo headphone devices to enhance spatialization of source around a listener

Utilization of filtering effects in stereo headphone devices to enhance spatialization of source around a listener

Utilization of filtering effects in stereo headphone devices to enhance spatialization of source around a listener

An apparatus for creating, utilizing a pair of oppositely opposed headphone speakers, the sensation of a sound source being spatially distant from the area between the pair of headphones, the apparatus comprising: (a) a series of audio inputs representing audio signals being projected from an idealised sound source located at a spatial location relative to the idealised listener; (b) a first mixing matrix means interconnected to the audio inputs and a series of feedback inputs for outputting a predetermined combination of the audio inputs as intermediate output signals; (c) a filter system of filtering the intermediate output signals and outputting filtered intermediate output signals and the series of feedback inputs, the filter system including separate filters for filtering the direct response and short time response and an approximation to the reverberant response, in addition to the feedback response filtering for producing the feedback inputs; and (d) a second matrix mixing means combining the filtered intermediate output signals to produce left and right channel stereo outputs.

Effects of relaxed music therapy on pain of patients undergoing colonoscopy

Objective To study the effect of listening to music with headphone or background music on pain reduction of patients undergoing colonoscopy. Methods 180 patients undergoing colonoscopy were randondy selected as the headphone group,background music group and the control group.The headphone group listened to relaxed music with headphone after measurement of vital signs.The background music group listened to relaxed music played by CD after measurement of vital signs.The control group did not listen to music.Pain degree was measured by pain intensity number scale during colonoscopy.Heart rate,blood pressure,saturation of blood oxygen and appraisal to the music by the former two groups were observed.Results Pain degree of the headphone group and the background music group was lower than that of the control group(P＜0.05).Pain degree of the headphone group was lower than that of the background music group with no significant difference(P＞0.05).Heart rate of the control group after colonoscopy was faster than before colonoscopy(P＜0.05).Conclusions Relaxed music can alleviate pain of patients undergoing colonoscopy.Listening to background music is a convenient and economical method for alleviation of pain without any side effects for patients undergoing colonoscopy. Key words: Colonoseopy; Relaxed music; Pain

Charaterisation of Zulu (Nguni) sheep using linear body measurements and some environmental factors affecting these measurements

Data on linear body measurements (LBM) of ca. 100 Zulu sheep raised under extensive management systems at four sites in northern KwaZulu-Natal were collected over a period of 2.5 years (October 2000 to May 2003). Data were used to quantify the live weight (LW), heart girth (HG), wither height (WH) and scrotum circumference (SC) of sheep in different age groups as well as the effects of some environmental factors on their LBM. Teeth numbers were used to estimate the age of sheep. The variation in LBM was influenced significantly by the location where an animal was raised and by its age. Mature rams that have three and four pairs of incisors had LWs of 37 and 38 kg, HG of 79 and 80 cm and WH of 65 and 64 cm, respectively. Mature ewes had LWs of 30 and 32 kg, HG of 76 cm and WH of 62 and 61 cm. Differences of 15 kg, 18 kg and 22 kg in LW among sheep with full sets of milk teeth and 28 kg, 35 kg and 40 kg among mature sheep were found between populations. The SC increased with age in mature rams (three and four pairs of incisors) and was 27 cm as compared to 18 cm for younger rams. Ear size ranged from ear buds to large ears of 9 - 14 cm. However, type of ear-length was found not to have any particular influence on the variation in LBM of Zulu sheep. It was concluded that an investigation of genetic variation between the populations would be necessary to develop effective conservation and utilization programmes and strategies for the breed. Keywords: Indigenous sheep, body measurements; scrotum circumference, extensive management South African Journal of Animal Science Vol. 37 (1) 2007: pp. 11-20

Binaural Rendering in MPEG Surround

This paper describes novel methods for evoking a multichannel audio experience over stereo headphones. In contrast to the conventional convolution-based approach where, for example, five input channels are filtered using ten head-related transfer functions, the current approach is based on a parametric representation of the multichannel signal, along with either a parametric representation of the head-related transfer functions or a reduced set of head-related transfer functions. An audio scene with multiple virtual sound sources is represented by a mono or a stereo downmix signal of all sound source signals, accompanied by certain statistical (spatial) properties. These statistical properties of the sound sources are either combined with statistical properties of head-related transfer functions to estimate that represent the perceptually relevant aspects of the auditory scene or used to create a limited set of combined head-related transfer functions that can be applied directly on the downmix signal. Subsequently, a binaural rendering stage reinstates the statistical properties of the sound sources by applying the estimated binaural parameters or the reduced set of combined head-related transfer functions directly on the downmix. If combined with parametric multichannel audio coders such as MPEG Surround, the proposed methods are advantageous over conventional methods in terms of perceived quality and computational complexity.

Headset with flashing light emitting diodes

A headphone system is provided with two earbud headphones and a control module, each fitted with a plurality of light emitting diodes (LEDs). The LEDs may be of many different colors and flash to the beat of the music. Patterns, colors, and intensity may be adjusted based on a user's preferences. The intensity, frequency, and light patterns of the LEDs may change when a threshold level is reached.

Multi-channel audio panel

A method and apparatus for providing improved intelligibility of contemporaneously perceived audio signals. Differentiation cues are added to monaural audio signals to allow a listener to more effectively comprehend information contained in one or more of the signals. In a specific embodiment, a listener wearing stereo headphones listens to simultaneous monaural radio broadcasts from different stations. A differentiation cue is added to at least one of the audio signals from the radio reception to allow the listener to more effectively focus on and differentiate between the broadcasts.

Adaptive Active Noise Control Schemes for Headset Applications

Abstract This paper presents the design and implementation of adaptive feedback active noise control system (ANC) for head phone applications. Active Noise Control is a technique of acoustic noise reduction using a secondary source of sound which produces “antinoise” to cancel the primary noise. In this paper, narrow band single channel feedback ANC for headsets application is focused upon. The filter weights are updated by using the feedback form of Filtered-X LMS (FXLMS) algorithm. Performances for the IIR-based filter, FIR-based filter are compared with those of the algorithm by using ADALINE. The real time implementation of the system is performed using TMS320C6713 DSP Starter Kit (DSK) and the performance is analyzed for two tone sinusoidal noise.

Meet the Archos 605

FRANKLY, I have felt guilty over the past several years for not discussing personal media players like iPods and for not covering more WiFi topics in this column. Maybe it is as the ancients thought, bad ether. Or maybe it is my love for things like high-definition video, five-channel surround sound, and fast and capable computers. But all that is about to change, as I am finally making the move to WiFi, personal media players, and take-it-anywhere technology. It pains me because until very recently, I have been more than happy with the technology I already have. It is the Archos 605 WiFi personal media player that lured me out of my wired comfort zone. I have ranted and raved about technology in the past, but the Archos 605 makes me stretch to find enough superlatives--and expletives--to describe it. I first learned about the 605 while reading an editor's review by Donald Bell on CNET (dated 8/30/07). While I consult CNET reviews often, the opinions that follow are mine and not quite the same as those of Mr. Bell. The Archos 605 is 4.75 inches wide, 3.25 inches tall, and slightly over half an inch thick. Most of the front is taken up by a gorgeous 4.25-inch (diagonally) TFT (thin film transistor) LCD (liquid crystal display) screen with 800 x 480 pixels. This screen, by itself, sets the Archos apart from nearly every other similar device, including the iPod. Two other features put the Archos in a category by itself: a 30-GB hard drive and built-in WiFi for wireless networking. The 605 is available with as little as 4 GB and as much as 160 GB of memory, but I suspect the 30-GB model will be the most popular, and it is the one I recommend. Another feature I like is the small speaker on the front that lets you listen to music without using those annoying ear buds. Together, these and similar features drove me to the store. The screen of the 605 is a multi-touch screen that turns into a qwerty keyboard when you need it. A multi-touch screen allows you to scroll up and down or side to side with a finger or a stylus--two of the latter are provided. There are also six buttons on the right side of the device that are needed from time to time, but you can generally use the touch screen. As soon as I got home with the 605, I turned it on and checked to see if there was any wireless coverage in my neighborhood, but there was none. I guess the local Starbucks is just too far away. Oh well, I think my son has a spare wireless station that I can use with my Mac mini and DSL line to create my very own WiFi network. I plan on setting up my home wireless network soon, but I want to make it as secure as possible, which might take a little study. Expect more on this topic in a future column. If you don't have a WiFi network, you can simply connect the 605 directly to a computer. The 605 comes with a special cable that connects it to the USB 2 port on a computer. You must have a USB 2 port, since this is how you charge the 605's batteries, and a USB 1 port does not have adequate power. Once connected to a computer, the 605 shows up on the Mac desktop or in My Computer on a PC. There are two ways to configure this connection: one makes the 605 appear as an external device; the other makes the 605 act as a Windows Media Player. The first connection method is the one I use, since it allows me to simply drag files to the 605 hard drive. The first order of business for me was downloading some music files from eMusic.com--an Archos partner. I like eMusic for three main reasons. First, the music, which costs 99 cents a song, is not copy protected, so you own it. That means you can transfer it from computer to computer and make as many CDs as you like. Second, I like eMusic because it features a wide selection of old folk, pop, rock, and country music that is nearly impossible to find elsewhere. For example, it was easy to find nearly a dozen versions of Donovan's Catch the Wind and a copy of Lonely Surfer by the Ventures. …

The Effect of Screen Size and Audio Delivery System on Memory for Television News

This experiment randomly assigned 63 undergraduate students to one of three conditions: large screen television with cabinet mounted speakers, conventional size television screen with cabinet mounted speakers, and small screen (2-inch diagonal) television with audio delivered via earbud headphones, to test the efficacy of screen size and audio delivery system in learning the facts from television news. The study hypothesized that the enhanced attention to the information-rich audio track created by use of earbud headphones would produce memory among subjects in the small screen condition equivalent to the two larger screen conditions. Results supported the hypothesis.

Foreword

Foreword

The Effects of Listening Environment and Earphone Style on Preferred Listening Levels of Normal Hearing Adults Using an MP3 Player

The main objective of this study was to determine the influence of listening environment and earphone style on the preferred-listening levels (PLLs) measured in users' ear canals with a commercially-available MP3 player. It was hypothesized that listeners would prefer higher levels with earbud headphones as opposed to over-the-ear headphones, and that the effects would depend on the environment in which the user was listening. A secondary objective was to use the measured PLLs to determine the permissible listening duration to reach 100% daily noise dose. There were two independent variables in this study. The first, headphone style, had three levels: earbud, over-the-ear, and over-the-ear with noise reduction (the same headphones with a noise reduction circuit). The second, environment, also had 3 levels: quiet, street noise and multi-talker babble. The dependent variable was ear canal A-weighted sound pressure level. A 3 x 3 within-subjects repeated-measures ANOVA was used to analyze the data. Thirty-eight normal hearing adults were recruited from the Faculty of Rehabilitation Medicine at the University of Alberta. Each subject listened to the same song and adjusted the level until it "sounded best" to them in each of the 9 conditions. Significant main effects were found for both the headphone style and environment factors. On average, listeners had higher preferred listening levels with the earbud headphones, than with the over-the-ear headphones. When the noise reduction circuit was used with the over-the-ear headphones, the average PLL was even lower. On average, listeners had higher PLLs in street noise than in multi-talker babble and both of these were higher than the PLL for the quiet condition. The interaction between headphone style and environment was also significant. Details of individual contrasts are explored. Overall, PLLs were quite conservative, which would theoretically allow for extended permissible listening durations. Finally, we investigated the maximum output level of the MP3 player in the ear canals of authors 1 and 3 of this paper. Levels were highest with the earbud style, followed by the over-the-ear with noise reduction. The over-the-ear headphone without noise reduction had the lowest maximum output. The majority of MP3 players are sold with the earbud style of headphones. Preferred listening levels are higher with this style of headphone compared to the over-the-ear style. Moreover, as the noise level in the environment increases, earbud users are even more susceptible to background noise and consequently increase the level of the music to overcome this. The result is an increased sound pressure level at the eardrum. However, the levels chosen by our subjects suggest that MP3 listening levels may not be as significant a concern as has been reported recently in the mainstream media.

Listen up! MP3 players can cause hearing loss

![][1] It seems most kids won't go anywhere these days without personal portable media players with earphones. iPods, MP3 players and other personal music players not only are the hottest devices for adolescents and preadolescents, the devices' ear buds (earphones) and personalized

Auditory feedback control for improvement of gait in patients with Multiple Sclerosis

Objective To study the use of auditory feedback for gait management and rehabilitation in patients with Multiple Sclerosis (MS). Methods An auditory feedback cue, responding to the patient's own steps in closed-loop, was produced by a wearable motion sensor and delivered to the patient through ear phones. On-line (device on) and residual short-term therapeutic effects on walking speed and stride length were measured in fourteen randomly selected patients with gait disturbances predominantly due to cerebellar ataxia. Results Patients showed an average improvement of 12.84% on-line and 18.75% residually in walking speed. Average improvement in stride length was 8.30% on-line and 9.93% residually. The improvement results are particularly noteworthy when compared with the lack of change in healthy control subjects. Conclusions Patients with MS using auditory feedback cues showed improvement in walking abilities.

Headphone

Headphone