Power On Self Test [POST] Sound - Not functioning

Question

The following applies to a Mac Pro early 2008 8 core 2.8GHz Xenon with 8GB RAM 4 x HDD none of which is more than 50% occupied, running Mac OS X Lion 10.7.1.
The same scenarios also apply to my Lion Clone HDD, it is regularly updated to keep abreast of changes, unfortunately it seems to have updated to an unwanted change?
Like all others after completing the POST the Mac normally emits a ‘gong’ sound.
I need to be able to mute this sound on demand in the small hours of the morning to avoid complaints of excess noise, but the present issue has placed this on the back burner.
Under Snow Leopard I was able to deploy an Application which created a System Preference. In turn this enabled the sound to be muted. However this was not ideal because it required accessing System preferences before shutting down, or leaving the sound semi permanently muted.
After searching for and testing various actions apparently designed to achieve this objective nothing seems capable of the task. Methods involving the use of Terminal were avoided as that is not my bag.
If it had functioned hitting the Keyboard Mute Key on start-up would have been ideal, if this does work for anyone please tell me.
Whilst it is accepted that the default for the POST Sound should be for it to be heard. Unfortunately Apple choose to be deaf, dumb and blind to the need for a User selected method of silencing the POST Sound that reverts to default after a single use.
Having temporarily given up on silencing solutions and made a decision to smother the sound with a duvet, or something similar for early morning start-ups, by an eerie coincidence the start-up sound ceased. The first reaction was ‘success’, but this was short lived when considering the need to access the Start-Up Management Screen and other start-up choices.
Exceptions to the above:
a. Re-booting from my Snow Leopard HDD, used to run items which do not work under Lion, back to Snow Leopard the POST Sound is audible.
When restarting from Lion and booting into Snow Leopard the POST Sound is not audible.
b. The first boot into Lion after using Snow Leopard the POST Sound is audible, but subsequent start-ups remain silent.
The following scenarios describe the attempts to return the Mac to normal operation:
1. System Preferences > Sound, this was checked to ensure that none of the settings blocked the sound.
2. Disk Utility was used to Repair the Start-Up HDD and also to Repair Disk Permissions.
3. Resetting the NVRAM was carried out several times, I have read that this could be beneficially allowed to repeat the POST Sound 4 times, so this was tried as well as the Apple directions which advise holding the keys until 2 sounds have been heard.
4. The Logic Board Battery was replaced.
5. Apple Hardware Test was run and returned the result [words to the effect] ‘No Trouble Found’.
The above seems to indicate that the issue is with Lion?
At this point I have run out of options other than to perform a clean install and hope that the issue will be resolved.
Although I have adequate back ups returning to a position with all the Applications set up properly is going to be a major task.
Any suggestions or ideas to move forward with this problem will be gratefully received.

Answer 1

Just to round off the above scenarios and answer the outstanding items as far as possible.
The above taught me a little about ‘Migration Assistant’, I have never previously had any occasion to use it.
By setting it up as near, IIRC, the settings used after re-installing Lion were similar to this:
Most Applications were fully functional without any additional action being required.
Several Applications required their Serial Number-Registration Code-or whatever, to be inserted MS Office 2011 required ‘Activation’.
Adobe Creative Suite 3 Master Collection, allowed Acrobat to open but reported that it needed one of the other related Applications to be opened.
After a similar experience with Photoshop Adobe decided that it was necessary to uninstall and reinstall CS3 to regain usability.
Inserting CS3 #1 Disc and hitting ‘Install’ revealed the true requirement.
CS3 needed to be ‘Repaired’.
The uside of this was that almost immediately an estimate of Time for the process was given, and this started to count down second by second, and when completed there was no need to enter the Serial Number.
Apple could learn something about ‘Estimating Time to Completion’ from Adobe.
The downside was that this, effectively, new installation required almost 20 updates to be applied amounting to about 750Mb, unfortunately this took as long as most Applications would take to install several Gbs and even this resulted in some failures for some component parts. CS3 runs as a damaged product in Lion.
Adobe seem to need to learn more about working with Mac?
Regarding the ‘outstanding irritations’ mentioned previously:
Please ensure that you read to the end of this post, I am not trying to ‘sell’ anything by offering these links.
Searching for an Application to mute the POST Sound I visited:
http://alphaomega.software.free.fr/downloads.php
This developer produces ‘Start-Up Chime Stopper’, more info on this can be found here:
http://alphaomega.software.free.fr/startupchimestopper/Documentation/Documentati on.html
After eMailing the Developer and receiving, IMO possibly related to language difference, an open ended reply I took advantage of the Free Download in order to trial this poduct.
It was found to be functional but it does not seem to be capable of applying a Mute to the POST Sound for a single event, other than by User intervention.
In fairness I may have missed something but believe all combinations of the settings were tested.
The upshot was that I removed [read trashed] this Application.
Having removed the Application on restarting the Mac, horror of horrors’, the POST Sound was absent.
A quick dive into System Preferences > Sound > Output tab > Internal Speakers, revealed that the setting had been left on Mute.
With the Mute checkmark removed normal service was resumed.
Also I subsequently found that altering the Volume Level reduced the POST Sound to an acceptable level.
In my earlier searches for a solution to Mute the POST Sound the System Preferences > Sound settings had been set every conceivable which-way.
No solution was found and this lead me to criticise Apple for not providing a means to turn off this sound when there was a real need to do so.
There seem to be a few possible explanations for what is happening now:
1. I failed, earlier, to test EVERY possible Sound Setting.
2. My recollection of events is completely off the rails and brain fade has set in.
3. My Sound Settings were corrupt and repaired by the reinstallation of Lion, I did not retest prior to the trial of Start-Up Chime Stopper.
4. Installing and removing Start-Up Chime Stopper has altered something within Sound.
Please can anyone help to confirm any of these items?
In the meantime I am a happy chappie, I have to listen hard for the POST Sound but have the comfort of knowing it is there.
That is until Apple spoil it again?