[Mogul, XV6800 ROM Development] pianoralf:
This is the method to adjust the volume of Bluetooth Headsets:

1. Install TotalCommander (if not allready done)

2. look in the registry which audiofile your device is actually using

-> \\\registry\HKLM\Drivers\BuildIn\WaveDev\

-> doubleclick "AcousticFile" and read the string and write it to a paper

3. change to the directory which you find in the string

-> usually \windows and copy the file from the HTC device to your Desktop PC

4. Make a backup of that file (so you have a copy if something goes wrong)

5. If your Excel can open it via doubleclick and you see the file in various colums go to step 6

If Excel opens it and eveything is in the first column (German Excel), then you have temporary (!) to change the field-separator for Excel, so that it reads and exports comma seprated files (otherwise it uses a semicolon)

-> close Excel

-> System(steuerung): Region and Languageoptions

-> change language for numberformat to "english"

-> Start Excel (look in Options "international" if there is a check box to use the numberformat from system language options)

-> Doubleclick the file and it will be opened in excel. When you save it later: use csv Format. Then Excel will use a comma as field seprator and not ";"

6. Doubleclick the file. It opens EXCEL and you see a table

In my version of the table I found 3 blocks with different headlines.

In the first column they you find the value "Header". Look at the last block. Here I found:

Header	Mode	Operator ID	Vocpath	volume_level	codecTxGain	codecRxGain	codecSTGain	txVolume	rxVolume	pcmFormatCtrl	ecSwitch	ecMode	ecStartupMuteHangoverThres	ecFarendHangoverThres	esecDoubletalkHangoverThres	hecDoubletalkHangoverThres	aecDoubletalkHangoverThres	ecStartupMuteMode	ecMuteOverride	ecStartupErleThres	ecForceHalfDuplex	esecResetThres	hecResetThres	aecResetThres	ecInputSampOffset	rxAgcEnableFlag	compFlinkStaticGain	compFlinkAIGFlag	expFlinkThreshold	expFlinkSlope	compFlinkThreshold	compFlinkSlope	rxAvcEnableFlag	avcRlinkSensitivityOffset	avcFlinkHeadroom	txAgcEnableFlag	compRlinkStaticGain	compRlinkAIGFlag	expRlinkThreshold	expRlinkSlope	compRlinkThreshold	compRlinkSlope	nsSwitch	nsMinGain	nsSlope	nsSNRThreshold	rxPcmFiltCoeff 0	rxPcmFiltCoeff 1	rxPcmFiltCoeff 2	rxPcmFiltCoeff 3	rxPcmFiltCoeff 4	rxPcmFiltCoeff 5	rxPcmFiltCoeff 6	txPcmFiltCoeff 0	txPcmFiltCoeff 1	txPcmFiltCoeff 2	txPcmFiltCoeff 3	txPcmFiltCoeff 4	txPcmFiltCoeff 5	txPcmFiltCoeff 6	ec_reset_flag	Reserved 2	Reserved 3	Reserved 4	Reserved 5	Reserved 6	MCC_Val	MNC_Val

So, interesting for bluetooth volume which is transmitted from the HTC device and received by you bluetooth device is the parameter: rxVolume

Normally the first data row is: (Here I have marked the columm rxVolume with XXXX for you)

E0	Default	0	0	5	4000	4000	0	C000	XXXX 422	FFFF	0	190	0	320	320	320	0	0	7F	0	300	300	3000	0	0	7F65	0	780	FF9A	1B0C	F333	0	ED00	0	0	7F65	0	780	FF9A	1B0C	F333	1	68	743E	6	417	FC95	60	EC7D	01D8	F16B	3D23	0	0	0	0	0	0	0	0	0	0	0	0	0	FFFF	FFFF

Now replace the value XXXX you find in your file with a higher Value.

Try 8000 9000 A000 B000 C000 E000 F000 or FFFF (for maximum)

This is an experimental way to have to try and test which value is good for you.

You can also replace the Word "Default" by the name of your device.

For that test replace one of the names your find in the second column with the exact name of your device which you find in then bluetooth settings (displayed after the coupling of the devices)

As experiment I added serveal lines mydevice_VOL1 mydevice_VOL2 etc to change the volume without booting the device. (For that change the name in the bluetooth setup to one you have used in that table)

For experiment: Maybe the parameter rxAgcEnableFlag also helps to get a better value. But I have not finished my test, so I hope others will find out which parameter should be used.

So notice:

When booting (reset) the device looks which file is to be loaded.

There may be several files on you device, but only one is used.

When I connects a bluetooth headset it looks in the table, if it finds the exact name of that device. Then it uses that line.

If not, it uses the line with "Default" in then second column .

6. Save it to your desktop PC.

7. Close Excel and if necessary restore the language setting for Excel in the windows language options to german.

8. Connect your HTC device and open then windows dir.

9. copy the audio file to the HTC device and replace the orginal file.

10 Reset the HTC device.

11. Connect the bluetooth device and test if the volume is good for you.

If ist is still too low or too loud change the value in rxVolume. For that I can not upload a file which will help all users.

You have to figure out it for your device.

In this forum there are some hints to change the BT channel. This will not increase the volume. Other people replaced the audiofile by try and error. Some had success. Maybe the name of their device was not found in the original audio file. So replacing the audiofile with a file which contained the name of their BT device helped some people but not all.

I did not find out, if it is possible to change the volume within a phone call, by using the HTC device volume adjust control at the left side of the phone.

HTC has used serveal lines with different volume settings

B6	PHONE_HANDSFREE_VOL0	0	0	0

B7	PHONE_HANDSFREE_VOL1	0	0	1

B8	PHONE_HANDSFREE_VOL2	0	0	2

B9	PHONE_HANDSFREE_VOL3	0	0	3

B10	PHONE_HANDSFREE_VOL4	0	0	4

B11	PHONE_HANDSFREE_VOL5	0	0	5

It corresponds to the 6 levels of volume control. But I dont't know if it can be used it via BT as well. I tested this but I had no success.

Maybe somone will find a switch for that.

Best greetings

Ralf