These are post from the earlier Joomla-based version of groffiti.com

The 2017 eclipse as seen from a Rest Area on I-95 in Lynchburg South Carolina.

A composite selected from about 50 shots.

Taken with Nikon D90 with a #14 welder’s lens as a filter.

Totality was so brief at this location that I wasn’t quick enough to get the filter off to get a picture of the corona. Our goal had been Santee, in the middle of totality, but traffic jams were getting thick, and we decided to play it safe.

The weather was excellent for most of the event.

Round trip 1300 miles.

I’ll try to do better with the 2024 eclipse visible (?) in northern Maine

15 June 2017 in Hearing

Another Hair Cell Issue

My upscale digital hearing aid had been erratic, would simply not turn on at times, and a bit later work well. A few months ago it seemed to be completely dead, so I took it to the audiology practice where I bought it a little more than 3 years ago (out of warranty).

He looked at it, and said “Oh, you have wax in the tube”, which was not evident to me, and I thought it would take some serious wax to make the device seem totally dead.

He replaced the tube, and one $60 office visit later the HA seemed to be working properly.

Recently the device showed the same symptoms, and this time I was sure the tube was clear. With magnification and bright light, I saw a fragment of hair (I still have some) in the battery compartment. I fished it out, and sure enough the HA then worked fine.

I suspect that this is a common occurrence. This HA uses a #13 battery, and one of the contacts is a palm-leaf sort of piece that simply lies against the cylindrical surface of the battery. A hair between those two surfaces will stop it dead. The other contact, which connects to the top of the battery, has a bit of a point on it, and would be less susceptible to this problem.

The #13 is a relatively large battery. This problem can only be worse with the tinier #10 and #312 batteries.

You might vaccuum out the battery compartment, but with those HA’s that are so small that “nobody knows you are wearing it”, be careful not to suck up the whole device. A simple puff of air might be sufficient. to clear hair out of the compartment.

<div id=”wishlist”> </div>ALD Wish List

24 September 2016

I’ve been using the Resound/Cochlear MiniMike for some time now, and consider it to be an essential accessory. It set me to thinking about what the ideal device in that kind of format would be able to do.

The (big) thumb-sized MiniMike transmits sound directly to my Cochlear N6 CI and Resound Verso HA via a paired connection that is similar to Bluetooth but proprietary You can also plug another audio source , e.g. radio or iPod into a 3.5mm jack.

My dream device would:

Pair and connect via a similar but not-proprietary connection (Bluetooth 4.0?) to a wide variety of HA’s and CI’s
Incorporate a microphone that is at least somewhat directional (MiniMike does this)
Incorporate a FM receiver that would receive the commonly used 72MHz hearing assistance band.
Incorporate an IR receiver
Charge via a mini-USB connector, which would also connect to a computer that would allow setting of parameters such FM frequencies, etc.
Incorporate a T-coil! Not an atavism; loop systems will continue to be useful, but putting the T-coil would solve the vexing and often ignored orientation issue. Tilt the device, not your head!
Allow plugging in an audio source such as an mp3 player (MiniMike does this) [update: 10/16]
Not be concerned with the telephone, although the mode of connection should be available for phones, The iPhone will connect to a few HA’s, but open standards seem to be an anathema to its maker.
Not attempt to handle multiple sources, e.g. the noisy dinner party. The pairing process that makes Bluetooth type devices work well would result in insurmountable headaches, I think.

I believe that such a device could be put into a package about the size of the MiniMike, with perhaps 3 buttons for control and a very simple display. Current devices such as the Williams FM receiver are much bigger packages, but follow design standards of several decades ago.

Don

Lee Williams

9 September 2016

Alead Wireless Microphone and Receiver

I’ve been trying out this Bluetooth transmitter(microphone) and receiver pair marketed on Amazon as “Alead”, although my transmitter is branded NolaN. The latter brand seems to be directed toward motorcycle riders, who have a very specialized need for hearing assistance! Alead literature mentions hearing assistance, but I don’t think I’ve ever seen anything directed to the HoH community.

Each unit is about the size of my thumb,charges via a mini-USB connection, and has a single button that controls ON/OFF, pairing, and volume control. The transmitter (microphone) has an A/B switch, more about that later.

My first thought about this was using the pair as a wireless Pocketalkerequivalent, for $100, a small fraction of the cost of most FM systems. Alead literature shows earbuds or headsets, but I found the a Williams neckloop worked well. I was concerned about a mono neckloop shorting out the right output of the receiver. It was a pleasant surprise to receive prompt answers from Alead tech support – should not be a problem.

Many BT systems have latency that makes them unusable for hearing assistance. The TX/RX pair is specified as 20ms, and was not detectable to my ears. I was able to pair the TX with another brand of receiver (Aluratek), andfound several tenths of a second.

There are a number of Bluetooth transmiter/receiver combinations available, but this is the only one I’ve seen the includes a microphone on the transmitter. More importantly, these others generally have high latency. They’re generally intended for music streaming or other applicatins where latency doesn’t matter.

This setup may work out well for live theater hearing assistance at a modest cost. The size of the microphone seems reasonable. I don’t know if there is some way to connect multiple transmitters to one receiver, but the cost of the Alead receiver is only a quarter of the cost of the pair, and a simple mixer could sum 4, 8, or more such pairs.

The A mode is used for connecting the pair, apparently in the A2DP profile, andthis seems to result in good audio bandwidth, to about 15kHz by a simple test. The B mode is not documented, but I found that it would connect as a remote microphone to a PC, but with audio limited to about 4kHz. Imposed by Handsfree profile, according the Alead tech support. I have used a Plantronics M70 telephone headset in this manner, and there I see audio to about 7kHz. Some smartphone apps will connect to a BT remote microphone. I don’t know about latency in this case.

There are several variations of the microphone available. The LiveMIC costs a little more, is a somewhat bigger package, has directional and cardioid mikes, separate volume control, and can accept a separate corded microphone, but otherwise seems similar. It’s worth considering, uses the same receiver.

I’m not going to assert that this setup will solve every problem, but it does seem to hold promise. Amazon is generally pretty good about returns, if things don’t work out.

BT devices must be “paired”, and this takes some attention to detail at first, but worked smoothly after a bit of practice.

You’ll need a headset, earbuds, or a neckloop (I used a Williams NKL001)

Noise Based Hearing Tests

24 July 2016

Here’s a different sort of hearing test, in two different versions:

Each consists of a noise signal lasting 30 seconds, which has no intelligible content, but is manipulated in various ways, but is always a hiss.

In the first version, the noise is “white”, meaning that it contains the same noise level at all frequencies, although the frequencies are limited with low pass filters. (band-limited white noise).

For the first 5 seconds, the noise has a 12kHz low pass filter (LPF) is applied. After 5 seconds, a 10kHz LPF is applied. If your hearing is good in the 10 – 12kHz range, you may notice a slight change in the noise, still a hiss, but somehow different.

After successive 5 second intervals, other LPF’s are applied, at 8, 6, and 4kHz. At the 25 seond point, a 2kHz LPF ends the sequence

Low Pass Filters

time, sec.      LPF, kHz
0                       12
5                       10
10                      8
15                      6
20                      4
25                      2

Another version of this experiment uses high pass filters (HPF) This gives an indication of low frequency hearing. The HPF knocks out low frequency noise, and if your hearing is good in that range, you will notice a change. In this case, the noise is “Pink”, with lower levels at higher frequencies, which is more representative of sounds that we deal with in real life.

High Pass Filters

time, sec.      HPF, Hz
0                      none
5                      200
10                   400
15                   600
20                   800
25                   1000

Note: These tests have absolutely no sort of validation. They are strictly experimental, and posted for general interest only. The results will be somewhat dependent on the audio components of your computer system, especially for low frequencies, and might not work well at all on phones and tablets. Feel free to download the mp3 files and play them on other equipment. Attribution appreciated for other use.

In my own case, without electronic assistance, I don’t detect the LPF until 2kHz, but with a cochlear implant, at 4kHz the LPF is evident.It’s generally said that speech recognition is largely bases on frequencies up to 4kHz.

In the HPF case, the CI is not very good at low frequencies, and I don’t notice the cutout until it reaches 800Hz.

The signals were generated and processed with Audacity, an open source audio processing program.

I worked as a design engineer with radio frequency equipment for many years, and often used noise-based tests. The notion of similar test for hearing was intriguing.

July 24, 2016
Comments and questions welcome.

Don

About TV Ears

31 March 2016

A hard of hearing friend asked me about the possibility of setting up a loop in her living room. Her husband uses the TV Ears setup, which serves him well, as his hearing loss is slight, and he does not use hearing aids apart from the TV Ears. She has T-coils and has used them occasionally. she was familiar with loop systems, as they winter in Sarasota, where they are more common than in the Philadelphia area.

I said she should simply get a TV Ears receiver with a neckloop and get the same signal as her husband. A call to TV Ears Customer Service provided the answer that disappointed but did not shock me – “We used to have a loop version, but dropped it some years ago because of poor sales”

A few minutes on Google and a few phone calls turned up an answer. The Canadian distributor for TV Ears bought the remaining stock of the loop version when they were discontinued, and has them available. He can only sell complete systems in Canada, but can sell components elsewhere. I promptly ordered one, received it in a week, and tried it out with a standard TV Ears system, and it worked fine. This was with a TV Ears 5.0 Digital, but the “digital” only means that it will accept digital audio from newer TVs. (Note: supposed to work with Dolby; I could only get it to work with PCM)

Problem solved for this friend, but I don’t know how many units tvears.ca has available. But TV Ears is IR-based, with a carrier of 2.3MHz (except for some early 95kHz units), so I saw no reason why some other 2.3MHz IR receiver would not work. And that is the case; the Williams RX22 tunes 4 channels, one of which is 2.3MHz. I obtained one, plugged in a neckloop, and it worked fine. TV Ears touts some sort of Voice Clarification Circuitry, which apparently is a glorified tone control. The receiver and a neckloop will set you back about $200. tvears.ca asks $100 CDN plus shipping. I had no customs issues with it.