Surround Sound FAQs Part 2

How is band-split directionality calculated?
Band-split directionality is calculated in all directionality modes according to the average of the hearing thresholds at 250 and 500 Hz. Hearing instrument style is also taken into account.

Is the determination for the band-split linked between the two ears?
No, the frequency where the band split defaults is calculated independently for each ear.

Will ReSound Alera give benefit to those with poor discrimination ability?
As a hearing aid, the ReSound Alera can be fitted on any individual with hearing loss that is deemed suitable for hearing instruments through audiometric evaluation.

How is ReSound Alera different from competitor hearing instruments that employ a band-split between low and high frequencies?
While the band split of competitors is fixed, the band split employed for ReSound Alera is adjustable, which means that the band split is optimally set for individual hearing losses.

Some competitive products allow for their band split to be turned off. Is this a disadvantage for ReSound Alera?
No. While the band split cannot be turned off in ReSound Alera, the dispenser has the option of changing the Directional Mix to its highest setting, which is similar to having it off but with better sound quality than if it were completely deactivated.

Is the Surround Sound Processor available on single microphone hearing instruments?
No, only on dual microphone hearing instruments.

How does the Surround Sound Processor work with a reverse slope hearing loss?
The Directional Mix is based upon hearing threshold levels, particularly for the low frequencies.  Therefore, reverse slope losses are more likely to have a higher Directional Mix setting, which would bring more directional cues down into the mid-frequencies where any directional benefit may be derived for a patient with this type of hearing loss.

Omni in low and directional high–what about the upward spread of masking?
Split-band processing does not over-amplify any sound for the patient.  It simply restores the balance of low to high frequency gain that the patient typically experiences in an omnidirectional program.  Therefore, upward spread of masking should not be viewed as a deterrent to fitting a split-band instrument.

How is the sound quality better in Alera in omnidirectional mode?
It should be neither better nor worse.  Surround Sound processing improves the sound quality of directional programs to be at least on par with the sound quality of omnidirectional programs, which historically has been the preferred mode for most patients.

Is the Surround Sound Processor always active (i.e. in quiet and noise)?
Yes.  Surround Sound processing is always active in directional programs, regardless of the environment.

If the Surround Sound Processor gives more bass what will it do to the sound of a patient’s own voice?
The Surround Sound processor does not give more bass than the omnidirectional program. The patient’s own voice should sound like it does in omnidirectional.

If the hearing aid is set to have no low frequency gain (i.e. normal low frequency hearing) how does the Surround Sound Processor benefit the patient?
Even with little-to-no low frequency gain, noisiness can still be an issue with directionality for patients with very good low frequency hearing. In fact, complaints of noisiness when in directional by patients with good low frequency hearing was a motivating factor in developing this feature. Surround Sound with its band-split directionality alleviates this problem of directional-induced low-frequency noise by processing low frequencies with a quieter omnidirectional response.

How is Surround Sound different from Oticon’s split-band directionality?
The frequency at which the bands are split is configurable, and results from a personalized calculation based on audiogram information and the form factor selected.

Is the Surround Sound Processor available in all models or just the high end?
All two-microphone Alera instruments have the Surround Sound Processor.

How does the Surround Sound Processor manage to keep the lows with an open fitting?
It does not keep the lows. The low frequency amplification will be the same as whatever it is in omni. So if there’s no low frequency real ear gain in omni, there won’t be any in directional, either. However, the sound quality in directional with Surround Sound will still be better than with full directional processing due to the lack of bass boost compensation with full directionality that typically amplifies the noise floor of the device.

What specific complaints might cause a dispenser to change the Directional Mix?
First, note that because the default settings in the hearing aid are designed to be a very good balance between comfort and clarity and because the mixing point is calculated automatically, the settings should only be changed when the user’s needs can be clearly and accurately assessed. However, if a user complains of difficulty understanding conversation in a noisy surrounding, the Directional Mix can be increased, thus providing directionality in more frequencies.  Alternatively, if the user complains that the hearing instrument is too noisy in quiet situations or desires more listening comfort, then the Directional Mix should be decreased.

This entry was posted in Sound Quality, Tech Tips and tagged , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s