Posted by - PSAPs.

Soundhawk, the Hearable Hero

Manufactured by Foxconn (iPhone manufacturer in China), and created by an all star team (including ex Apple, Adobe, Cisco, Amazon, Motorola , HP, Jawbone staff), the Soundhawk Smart Listening System promised to be the the killer PSAP (Personal Sound Amplification Product). The Soundhawk sports a simple and elegant design, is bundled with a remote microphone system, and caters to the needs of both Android and iOS users. The Soundhawk was also the first PSAP to be successfully marketed as wearable device (in the ever-trendy hearables category). This gave the Soundhawk a huge, and unprecedented, boost in popular media coverage (for a PSAP).

Our SoundHawk Smart Listening System

Our SoundHawk Smart Listening System

PSAPs and Hearing Loss

Before getting to our in-depth Soundhawk review, I’d like to take a moment to reflect on the topic of PSAPs and hearing loss. As mentioned in our previous blog post about the Soundhawk, PSAPs are not technically intended to help with hearing loss. Here’s a snippet from the FDA’s draft guidance on the topic:

PSAPs are intended to amplify environmental sound for non-hearing impaired consumers. They are intended to accentuate sounds in specific listening environments, rather than for everyday use in multiple listening situations. They are not intended to compensate for hearing impairment or to address listening situations that are typically associated with and indicative of hearing loss.

Let’s take the Soundhawk’s marketing:

We created Soundhawk to help people hear more of what matters most even in the noisiest places. It’s designed for those who struggle to hear soft sounds, converse over distance (such as talking to someone who is in another room) and understand speech in noisy environments.

While the FDA draft guidance is still only a draft, it certainly seems that Soundhawk’s marketing is in direct opposition to the guidance. Hearing soft sounds, hearing speech from a distance, and hearing speech in noisy environments are all situations where someone with hearing loss might struggle. However, I must admit, the FDAs guidance is extremely murky. Here is the list (of examples) of “intended” uses for PSAPs:

A PSAP may help with:

  • hunting (listening for prey)
  • bird watching
  • listening to lectures with a distant speaker
  • listening to soft sounds that would be difficult for normal hearing individuals to hear (e.g., distant conversations)

A PSAP may not help with:

  • difficulty listening to another person nearby
  • difficulty understanding conversations in crowded rooms
  • difficulty understanding movie dialogue in a theater
  • difficulty listening to lectures in an otherwise quiet room
  • difficulty hearing the phone or doorbell ring
  • difficulty listening situations in which environmental noise might interfere with speech intelligibility

This dichotomy seems extremely unnatural to me. Don’t people with normal hearing struggle to hear speech in crowded/noisy rooms too? It seems to me that the FDA is attempting to create two separate classes of hearing devices, where the only real difference is the marketing message. And there’s one huge problem with this approach: Even if PSAP manufacturers restrict their marketing message, the FDA can’t stop people from openly discussing their uses.

Let’s take a look at some of the consumer reviews on Soundhawk’s Amazon page:

Here’s a review snippet from user “kam” on December 2, 2014:

I have very bad hearing loss in my right ear and moderate hearing loss in the other…When I purchased my Soundhawk, it was with the hope that it would help my hearing in my right ear, but it did not. I called customer support in hopes I could turn it up (they were extremely helpful), but instead they suggested I use it in my left [good] ear. I tried it, and wow!

Here’s another from “Eric Stephan” on January 24, 2015:

I am a retired dentist. Hearing loss is very common amongst us…I was rather skeptical of this SoundHawk device but decided it was worth a try, particularly with the money back guarantee. I had nothing to lose. WOW!

Here’s “law prof” on January 23, 2015:

Soundhawk’s modest disclaimer about who its product is likely to benefit understates its power and value of the product for moderate hearing loss.

Lastly, “Peter T. Christy” on January 23, 2015

Soundhawk easily compensated for my hearing loss, but its additional features were an unexpected delight.

Let’s just accept the reality:

For better or for worse, people with hearing loss are using PSAPs to treat hearing loss. Let’s move on and talk about the potential of PSAPs for hearing loss, and then how the Soundhawk might actually work for someone with hearing loss. While we don’t officially endorse using PSAPs for hearing loss, we feel the audiology profession has a responsibility to help consumers make the right decisions.

Why I’m Excited about PSAPs

If you haven’t heard, there are a lot of people out there with hearing loss, many of whom need help:

Among adults aged 70 and older with hearing loss who could benefit from hearing aids, fewer than one in three (30 percent) has ever used them. Even fewer adults aged 20 to 69 (~16 percent) who could benefit from wearing hearing aids have ever used them. – More

Why do so many people neglect their hearing? There’s been a lot of speculation on this topic, and I won’t attempt to rank order the reasons.. but I can say that hearing loss denial, hearing aid stigma, and the cost of hearing aids have been significant factors in many studies. While PSAPs can’t help people overcome denial, they may help to overcome the stigma and cost barriers.

…over-the-counter [hearing] devices could reduce stigma, increase awareness of hearing healthcare, and improve [hearing device] adoption rates. – More

With the hearables market expected to grow to $5 billion by 2018, it’s clear that consumers are ready to embrace ear-level technology. For millions of people with a hearing problem, this revolution offers the chance to achieve better hearing anonymously and for a fraction of the cost. Inexpensive devices, like the Bragi Dash, could easily be shipped with an optional speech amplification/enhancement feature, and no one would ever know if you were using the device for heart rate monitoring, hands-free calling, or hearing improvement.

Why I’m Terrified

There’s a potential downside to the hearable revolution. Price conscious consumers may skip the audiological consultation all together, and jump straight to the solution (a PSAP, in our hypothetical world). While doing so may be harmless in many cases, some won’t be so lucky. Hearing loss may be caused by a number of underlying medical conditions. Some of these conditions are progressive, and without diagnosis and intervention, may lead to poor health or even death. I would recommend that anyone considering a PSAP solution first consult an audiologist to rule out any potentially harmful medical conditions.

Consulting an audiologist comes with other benefits. You’ll also learn how severe your hearing problem is, and whether a PSAP has the potential to help. 

In-Depth Soundhawk Review

First let’s take a look at the specs. I won’t go into the specs published and readily available online, but rather the amplification, frequency response, distortion, etc specs.. the type of specs one might read on a hearing aid spec sheet – reference.

Soundhawk ANSI Specs

Frequency Range: <200-8000Hz
SSPL-90: Max 108dB @945Hz
HFA OSPL-90: 106dB
HFA Full on Gain: (Min/Max) 2dB/32dB

THD
500Hz <1%
800Hz <1%
1000Hz <1%

Equivalent input noise 31dB

For comparison’s sake, let’s have a look at the NP (Normal Power) version of one of this years most popular hearing aids.

Resound LiNX 61 Specs:

Frequency Range: <100-6930Hz

SSPL-90: Max 114dB
HFA OSPL-90: 109dB
HFA Full on Gain: 43dB

THD
500Hz <0.5%
800Hz <0.6%
1600Hz <0.8%

Equivalent input noise 24dB

When the Soundhawk is compared to a standard hearing aid, in terms of raw audio specs, we can see there isn’t a huge difference between the devices. The Soundhawk wins on having a slightly broader frequency range (more sound above 7kHz). The LiNX wins on heaving more amplification in the high tones (HFA Gain) and a lower internal noise level (equivalent input noise).

Note: These specs give a general idea of performance but are not directly comparable due to Soundhawk’s use of the 1989 version of the ANSI standard test).

So what do do these specs tell us? Does this mean you can expect the same performance from the Soundhawk as you could from the Resound LiNX aid? The quick answer is no. Specifications are measured in a controlled environment – In a test box where where sound from the hearing device’s speaker is not allowed to re-enter the device’s microphone port (a common cause of audible feedback which limits useful amplification). Furthermore, audio processing features are disabled during ANSI tests, to ensure all devices are tested on an equal footing. This means digital noise reduction, and other technologies, are not affecting the audio produced during the test. In other words, this is no way of evaluating the device’s function in the real world. To find out the realistic amplification characteristics, the Soundhawk needs to be tested in a test box and on the ear (via “real ear measurement” testing), without switching off audio processing features.

Test Box Measurements

We tested the following features in the test box to find out more about the Soundhawk:

  1. Amplification performance
  2. Directional microphone performance
  3. Noise reduction performance
  4. Wireless mic performance in quiet and in noise

We used the following setup for the Soundhawk, for all test box tests:

Soundhawk in a Verifit Test Box

Soundhawk in a Verifit 2 Test Box

Our Test Box Setup

The Soundhawk “scoop” is seen in the center of the image (above).  The scoop has a microphone and speaker. It’s job is to pick up the sound, process and amplify it, and send the resulting sound into your ear. The scoop is plugged into a sound measurement coupler (the shiny metal device) with some blu-tack (to ensure a good seal). The black speaker (in the rear of the photo) emits a speech sound which is picked up by the reference microphone (the black wire sitting just below the Soundhawk). The sound from the speaker also enters the microphone on the Soundhawk (which is on the bottom of the Soundhawk, right next to the reference microphone). The processed/amplified sound is sent from the Soundhawk into the coupler, where it is picked up by the coupler microphone and compared to the sound which is measured at the reference microphone. The difference between these sounds (coupler vs reference) shows us what effect the Soundhawk has had on the sound.

Note: The speech sound is controlled for level and spectrum by the reference microphone. 

Speechmap Test

The first test we performed was the speechmap test. In this test we present the Soundhawk with some speech (at conversational level) from the Verifit speaker, and measure the performance of the device. On the graph below the green range illustrates the sound output envelope for the Soundhawk while the grey range shows the sound envelope with no amplification applied.  We set the Soundhawk on the following settings for this test: On the “indoor” mode with the volume controller 3 steps from the top. For tuning we dropped the touch screen pin in the middle of the screen, between “full” and “bright,” and with half “boost.”

Note for audiologists: We used Speech-std(F) at 65dB

speechmap_snip2

 

app_shot

The results of the test show significant amplification from about 1000Hz through to above 8000Hz. There is roughly 20dB of amplification from 2000-6000Hz. A small amount of amplification may also be seen in the lower tones. What does this mean? Well, it means that, in an occluded (closed) environment, the Soundhawk is providing amplification successfully through a range of tones that are important for understanding speech, and that the Soundhawk should be effective as a speech boosting device for people with a certain type of hearing loss. However, there is one major limitation to these findings:

We are still only looking at how the Soundhawk performs in a test box.

At this stage, the Soundhawk is coupled tightly to the “coupler” and no sound is leaking out (i.e., an “occluded” or closed configuration). Only the sound coming out of the Soundhawk is being measured by the measurement microphone. Since the Soundhawk would typically be worn in a more “open” (less occluded) situation, where both 1) sound that naturally enters the ear and 2) amplified sound that comes from the Soundhawk would mix together – and where some of the amplified sound could “leak” out – this measurement may not be representative of actual use. In our next post, we will test the Soundhawk on an actual ear, rather than in a test box, where we can create the “open” environment more typical of actual use, and share that result with our readers.

For those who are curious, here are some more Verifit screenshots showing what the Soundhawk was able to do with the same settings for various input levels, and with max volume and max boost.

Directional Microphone Test

The next test we performed in the test box was the directional microphone test – designed into the Verifit 2 system. We were generally impressed with the directional microphones, but were surprised to find that the indoor setting outperformed the dining setting for directionality. As you may or may not know, directional microphones are designed to improve the signal-to-noise ratio of a person’s speech in a noisy room, etc, so we’d expect the greatest directional effect in the dining setting.

Based on the marketing literature, Soundhawk seems to agree:

Dining: De-emphasizes sounds from behind and beside you, helping you focus on people talking in front of you.

dmic

Note: We used the same volume, boost, and full/bright settings as above.

In the image above you can see a series of pink and green curves. The green curves represent the indoor setting, while the purple curves represent the dining setting. The difference between the two green curves shows the difference in sound level when the sound is coming from the front (thick curve) or coming from behind (thin curve). The same is true for the purple curves. Two things are clear when looking at the graph:

  1. The directional microphone system appears to well through about 4000Hz, and provides some signal-to-noise improvement in the higher tones
  2. The directional microphone system works better in the indoor setting than the dining setting

You may recall from our speechmapping test that the Soundhawk primarily amplifies sounds from 2000Hz and above. So it looks like there should be some signal-to-noise improvement in the part of the pitch range that is amplified. This is a good thing for bringing up some speech sounds over the background noise!

Noise Reduction

For the noise reduction test, we put the Soundhawk onto the “Driving” Sound Scene. According to Soundhawk’s publications, the driving scene “reduces road and wind noise” … What this means is that the Soundhawk is looking to reduce steady-state (or constant, non-fluctuating) sounds like the drone of the road on the highway, or a steady breeze. Our Verifit system was equipped with “air conditioner” and “vacuum” sounds, so we used those sounds to test Soundhawk’s noise reduction functionality.

noise_reduction

As you can see in the image above, Soundhawk provides about somewhere in the range of 5-7dB of noise reduction for sound levels between 50-70dB (in a test box).

Sound Samples – Wireless Mic

We recorded a couple sound samples of the Soundhawk using the wireless microphone. In the first sample, “Bar Noise Wireless Mic,” you can hear me speaking into the wireless microphone and recording the output from the scoop. There’s a little bit of rustling in the sound sample, and that’s just me holding the wireless mic in my hand (slight movements and touching my chest with the mic). The sound you hear in both samples is 100% Soundhawk – the scoop is completely closed off from the outside world in the test box, and our test box microphone can’t hear anything else (but the scoop output). We were careful not to clip the recording, and have attached an image of the collected waveform to illustrate this.

In the second sample, “No Background Noise Wireless Mic” you can hear the clarity of the Soundhawk’s wireless microphone system with no background noise present. We were curious to know how well the system worked in an ideal environment (one without noise). Click on the links below to listen to each clip:

Waveform recording

Waveform recording

Conclusion

So far, we’re generally impressed with the Soundhawk’s technology.

  • Amplification is being provided successfully through a range of pitches important for understanding speech
  • The directional microphone system provides some signal-to-noise enhancement in the pitches that matter – works best in the “Indoor” setting
  • We are seeing 5-7dB of noise reduction for steady state noises between 50-70dB
  • The wireless mic system works well in quiet and in noise

While we’ve taken some steps toward understanding the technology behind the Soundhawk, we still don’t know who the device is optimized for.

In our next round of tests, we’ll submit the Soundhawk to a series of “real ear” measurements, to find out just how much amplification is possible with the device in the real world. These tests will help us determine the ideal (and less than ideal) hearing loss candidates for the Soundhawk. We’ll be sure to provide more measurements and sound samples, to help our readers decipher our findings. Stay tuned!

Contributions to this article were made by David Smriga at Audioscan. The Audioscan Verifit 2 measurement device was supplied by Audioscan for the express purpose of assessing the Soundhawk.

UPDATE: Part II of this review has been posted. 

UPDATE 2: Soundhawk has officially responded to our review.

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