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I have a first-generation MacBook, which are notorious for having a very low max sound output level when using the built-in speakers. I'm looking for a good software solution (i.e., no suggestions for headphones/external speakers) to boost the maximum sound output-level.

My main criteria is this: I don't want something that's app-specific, such as using VLC's built-in volume control + equalizer. I'm looking for something that either works system-wide for all sound output, or can be used with any app.

The best solution I've run across so far is described here -- it details using Audio Hijack Pro to hijack any given app's sound output and boost it with AH's equalizer controls.

While the Audio Hijack solution works okay, what I'd really like to find is a control panel or background app that puts an icon in the menu bar with either a system-wide toggle or an app-selector to toggle the volume boost for the chosen app.

Any alternatives that are better than the Audio Hijack solution?

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What are you outputting to? Internal speakers, headphones, external speakers? – Troggy Aug 12 '09 at 23:23
This is just the internal speakers. I indicated software as I'm not interested in solutions suggesting I use headphones or external speakers. I'll update the question. – arathorn Aug 12 '09 at 23:25
Is it only with certain videos or music or just in general? Cause the internal speakers can only go so loud. – Troggy Aug 12 '09 at 23:27
@Troggy: Sure, but, like I said, this particular line of MacBooks was notorious for a really low max level on the internal speakers. The later generations don't have this problem. – arathorn Aug 12 '09 at 23:29
up vote 3 down vote accepted

How About Rogue Amoeba's SoundSource? I'm not sure if it does exactly what you want, but give it a try. The price is right. Otherwise Audio Hijack Pro was going to be my recommendation.

For a hardware solution check out HeadRoom's Total Airhead or Total Bithead, which besides amping up the volume, it will help the sound quality if you don't have the most efficient headphones. This is very dependent on what headphones you have.

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Well, SoundSource doesn't do any volume boosting, but +1 for the app as it might end up being part of an improved solution. – arathorn Aug 13 '09 at 13:25
Although, I notice that most of SoundSource's functionality is now built-in to 10.6, by option-clicking on the sound volume menu bar icon. – arathorn Sep 1 '09 at 18:49
Thanks. I hand't noticed that. Also 10.6 is much slower to switch to headphones than any previous version of OS X. – Mark Thalman Sep 2 '09 at 10:32

Apple's engineers had second thoughts about the operating margins of the early MacBook's speakers, but had them too late in the game to re-specify the hardware. They used a kernel extension plug-in as a software workaround to restrict the MacBook's available gain potential. The plug-in also lists which digital signal processes are available for applications to hook into, as well as spelling out the upper and lower limits the processes may use. The goal was to eliminate all the conditions which could be tough on little speakers, not just put a cap on the amplifier.

Apple was concerned that if the iTunes equalizer, as an example, had access to the full capacity of Intel's codec, (which Apple can't mess with), and if a user set the low frequencies to boom-box levels, it could end up being a one-time-only event. Indeed, the engineers' caution has the plug-in adjust the volume of the startup chime to adapt to whatever DSP settings might be in force during a boot.

So much for the history lesson. Before even thinking of doing anything I suggest, visit Apple's site to verify you have installed all of the appropriate Firmware Updates for your MacBook. Doing so could provide the simplest solution possible. Although it wasn't true for everyone, many MacBook owners reported Firmware Update 1.2 cured their low volume issues. (Not all updates are apropriate for all models.)

If that doesn't work, here's how to tear out all of the Apple engineers' hard work, and thereby restore the defaults Intel built into its audio chip and associated codec. I came up with this inelegant hack after weeks of thrashing around with the concept, but lacking any existing knowledge. While the final product fixed my old, nearly-voiceless MacBook, I never could get it going for more than a few minutes at a time on my Sister's MacBook. 50-50 odds like that are acceptable when there's no money on the line to pay for the fix.

Before I posted this, I tested each command by cut-and-pasting it into the Terminal. With a backup in place, none of this is dangerous or touchy or even particularly interesting. Especially my attempts at humor. Still, anyone proceeding on from here should be competent enough to catch typos or syntax errors. If something Really, Really Bad happens while following my instructions, it may be my fault, but it's your computer.

Still with me?

Okay, safety first. Make a backup of the file we're targeting for modification:

sudo cp /System/Library/Extensions/AppleHDA.kext/Contents/PlugIns/AppleHDAPlatformDriver.kext/Contents/Info.plist ./Info.plist.bkup

Let's not perform brain surgery on the wrong patient:

defaults read /System/Library/Extensions/AppleHDA.kext/Contents/PlugIns/AppleHDAPlatformDriver.kext/Contents/Info | egrep "MuteGPIO = 1342242829"
| wc

The response should be the numeral 12. If it isn't 12, stop. No harm has been done. Should you care to oblige me, you might post your result.

Otherwise, let's make one more duplicate of the Info.plist file, which we'll use as a working copy. The installed copy and the working copy need to have the same name, so they can't be together in the same directory. I nominate the Desktop to be as good a place as any to put the working copy:

sudo cp -n /System/Library/Extensions/AppleHDA.kext/Contents/PlugIns/AppleHDAPlatformDriver.kext/Contents/Info.plist ~/Desktop/Info.plist

It's our working copy, so let's work on it:

defaults delete ~/Desktop/Info IOKitPersonalities

The sharp-eyed individual will note that the path to the file stops at 'Info', leaving off the .plist extension. That is not a typo. It's just another Apple usage eccentricity, this time in the syntax of the defaults command insists on.

To pull off the file-swap without annoying the system, we need to induce a temporary state of audio amnesia in Mr. MacBook. Oh, good, here's a rubber mallet:

sudo kextunload /System/Library/Extensions/AppleHDA.kext/

Now we overwrite the original .plist by dropping our renamed working copy back into the directory it came from. Fortune favors the brave, and all that, but I always check to see if the backup's still there just before I do this:

sudo mv ~/Desktop/Info.plist /System/Library/Extensions/AppleHDA.kext/Contents/PlugIns/AppleHDAPlatformDriver.kext/Contents/

TTime to revive the patient:

sudo kextload /System/Library/Extensions/AppleHDA.kext/

The transplant will have affected Mr. MacBook's personality, and he may start behaving in ways you're not used to -- such as, for instance, playing his music so loudly you're unable to avoid hearing it.

The change should take effect right away, but if not, then restart and check your audio settings in System Preferences. If you can't detect any improvement in volume, then the prudent thing to do is to restore the hacked Info.plist with the backup copy:

sudo mv /System/Library/Extensions/AppleHDA.kext/Contents/PlugIns/AppleHDAPlatformDriver.kext/Contents/Info.plist.bkup ./Info.plist

... which will leave everything exactly as you found it.

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I ran across this thread over at the Apple Support Discussion forums -- definitely looks like it's got potential. Will try it out and update this answer with the results. If anyone else tries this, please comment on your results.

I haven't been able to follow the setup instructions described in the thread -- I'm not very familiar with Audio Lab or MIDI configuration in OS X. Anyone else tried this?

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Hear looks like it would do the trick, and they do have a free demo. It has a system-wide equalizer and per-application settings as well. Also, this program is compatible with Snow Leopard.

It has a favorable Macworld review as well. I'll have to give it a try on my MacBook and I'll updated when I've tried it.

Update: It looks like this does the job. Note that on the EQ the preamp supports positive values.

enter image description here enter image description here

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When I ran Debain Woody, with MPlayer on an original 2001 iBook, it would set the volume to "max" each time it quit, yet the slider would be in the middle the next time you started it. After a few iterations of sliding it up, and down, and wondering why it kept getting louder, I blew the speakers (during a reboot). So, I think it's possible, try using the mac version of MPlayer, but do you really want to do it?

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Like I said, I've been doing this with Audio Hijack without any problems. I'd say I'm boosting the volume by around 20% -- nothing outrageous, and it's been working fine for me for well over a year now. I'm just looking for a more streamlined method to do the volume boosting. – arathorn Sep 2 '09 at 0:48

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