Thread Subject: Re: Telecom Subcomm Summary of 11.6.06 conf.Audio Output

Note

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From: Gregg Vanderheiden
Date: Wed, Nov 08 2006 10:00 AM

Note re decibels.



Doubling may be in 10 or 6 db chunks depending on what you are measuring



For loudness 10db is considered twice as loud.



See "about db' at
<http://trace.wisc.edu/docs/2004-About-dB/index.htm>
http://trace.wisc.edu/docs/2004-About-dB/index.htm




Gregg
-- ------------------------------
Gregg C Vanderheiden Ph.D.






_____


From: = EMAIL ADDRESS REMOVED =
[mailto: = EMAIL ADDRESS REMOVED = ] On Behalf Of Brooner
Mary-AMB004
Sent: Tuesday, November 07, 2006 12:08 PM
To: TEITAC Telecommunications Subcommittee
Subject: [teitac-telecom] Telecom Subcomm Summary of 11.6.06 conf. Audio
Output

TO ALL WHO WERE ON THE CALL: IF YOU HAVE EDITS or ADDITIONS TO THIS
SUMMARY, PLEASE FEED BACK TO ME. I will make changes on a master and submit
to the WiKI on Wednesday. my direct email is = EMAIL ADDRESS REMOVED = .
thanks, mb



################

The topic discussed was Audio Output. This topic will be continued in the
next call, Monday, 11.13.06.



**Initial clarification to focus the discussion: we agreed our discussion
would be on ACOUSTIC Audio Output, meaning from my voice to ears with
hearing loss. Further agreed, Acoustic Audio Output includes tonal output
if intended for the ear.



**Sharing of information about some questions quickly narrowed to where the
20 dB requirement came from. It was agreed that it has been around for some
time going back to wireline HAC proceedings at the FCC in the 1980's. 18dB
is from the HAC Wireline proceeding (1982). It was pointed out that any dB
not a multiple of 6 makes no sense because the gain doubles in multiples of
6. For example 18dB is twice the gain of 12 dB. Noted that special
transducers are needed in handsets to achieve even 20dB.



**Question raised who does 20dB help and was it intended to be built in to
all phones for 508 Standard or as an add-on. Most people hard of hearing
("HoH")have high frequency loss; it's not all about volume. Control of
ambient noise an issue for HoH, separate issue from volume. There was
belief in call group that 20dB intended to be in all handsets under 508
procurement, but it was noted by a vendor of 508 telecom equipment that when
offered, it had never been accepted by the procuring officers except as an
add-on.



**Clarification raised to explore what may be differences in wireline and
wireless equipment. It was noted that powering higher gain on wireline
system may be achievable but powering on a wireless system might require
fundamental alteration or batteries of infeasible size. Question was asked
if any studies exist. Technical question also regarding conflicting
standards and specifications between GSM Standards for GSM product and 508
standard for volume of 20dB.



**Automatic Volume reset. It was suggested that this perhaps should remain
a requirement for wireline handsets but should not be required for wireless
handsets because of their more personal use. General agreement on this
point.



**Note was given that whatever the subcommittee recommends, we will be asked
to provide cost impact and if a significant cost, it will be a tougher row
to hoe to get into the standards. Brief discussion of whether to have
compromise positions, but no conclusions made.



**This topic to be continued in next meeting, 11/13/06 at 2 pm EDT. Chair
agreed to research the French requirements on volume levels of devices for
public use.



Submitted by Co-chair, Mary Brooner

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