Speaker Boost app

[pruss]

I released a free Speaker Boost app, on both Android Market and Amazon Appstore, to boost the speaker volume. It's very simple. Don't set it too high or you might damage the speaker (I haven't done any long-term testing, so I don't know how important this warning is).

It's supported by an ad for my products, but if you have a paid version of any of my apps (e.g., ScreenDim), the ad doesn't won't even show up.

[C.S.]

I'm assuming this is the one you mean?

http://www.amazon.com/Omega-Centauri...dp/B008BTX2CA/

This is exactly the type of app I've been looking for. Thank you.

I tried a different volume app before but unfortunately didn't notice any difference.

I'm looking forward to trying out yours.

Don't set it too high or you might damage the speaker (I haven't done any long-term testing, so I don't know how important this warning is).

But didn't you create the app? So, wouldn't you have implemented the warning yourself? Then how can you not know if it's important or not important? Forgive me if I'm missing something obvious.

[pruss]

Originally Posted by C.S.

But didn't you create the app? So, wouldn't you have implemented the warning yourself? Then how can you not know if it's important or not important? Forgive me if I'm missing something obvious.

I know that other sound boost apps have a warning, so I am putting it in. I can't afford to destroy a couple of devices to test this.

I don't do anything undocumented here: all I do is ramp up every equalizer band. The Android SDK doesn't have any warning that I can see. Since all the app does is follow documented APIs, I think if you had any damage, you should be able to make a warranty claim on the device. But I don't want to take responsibility.

And of course if you plug in earphones and ramp up the volume, you can get ear damage. This presumably depends on too many variables to test: the precise type of sound you're listening to, your hearing and the type of earphones.

[C.S.]

Originally Posted by pruss

I know that other sound boost apps have a warning, so I am putting it in. I can't afford to destroy a couple of devices to test this.

Does that mean you haven't tested it at all, or that you just haven't tested it past the "warning" volume?

[Jessica Lares]

You can destroy your speakers by just using the maximum volume the system has for long periods of time. I have done that in the past anyway. I think it's safe to say that because the Kindle has low volume in the first place that 10-20% more wouldn't do too much harm. Bigger issue with music, video/voice should be okay.

[geekmaster]

Originally Posted by Jessica Lares

You can destroy your speakers by just using the maximum volume the system has for long periods of time. I have done that in the past anyway. I think it's safe to say that because the Kindle has low volume in the first place that 10-20% more wouldn't do too much harm. Bigger issue with music, video/voice should be okay.

What Jessica said is true because long periods at high volume can heat the speaker voice coils enough to melt the glue that holds them together, allowing the voice coils to come in contact with the magnets (scratchy sound) or to melt the insulation on the wire (burnt smell), or even to melt the tiny voice coil wires themselves (complete sound failure). How high you can adjust the volume depends on the average volume of the music or other audio you are playing. Audio books (and other low average volume sources) should be safe (to the speakers) at a much higher peak volume level than music.

[bjones6416]

Thanks so much for this app! I gave my 91 year old mother a Fire for Mother's Day, but she can't hear videos without using headphones, which she hates. I tried Volume+ but it didn't do much. Your app works great for her.

[pruss]

Originally Posted by C.S.

Does that mean you haven't tested it at all, or that you just haven't tested it past the "warning" volume?

I've run it (or an equivalent app) on a Fire at 40% and on my Galaxy S2 at 100%. But one doesn't expect problems immediately--the question is how long the volume can be sustained.

Anybody know if I can make it safer by keeping the volume low at the low frequencies, or at the high frequencies or the like?

[pruss]

I decided that because of the speaker damage worries I would add a more prominent click-through warning. I also removed the ad to make it a not-for-profit application. (Though there is still a link to my apps.)

Source code is available at code.google.com/p/speakerboost

[geekmaster]

Originally Posted by pruss

I've run it (or an equivalent app) on a Fire at 40% and on my Galaxy S2 at 100%. But one doesn't expect problems immediately--the question is how long the volume can be sustained.

Anybody know if I can make it safer by keeping the volume low at the low frequencies, or at the high frequencies or the like?

Low frequencies are more likely to cause heating. High frequencies are more likey to cause impulse damage (causing the speaker voice coil to travel beyond its design limits, possibly damaging it). Hopefully, the device is designed to prevent driving the speaker into potentially damaging conditions, but audio test CDs do come with a warning that they contain audio waveforms (such as square waves) that could potentially damage speakers and should not be used at full volume.

Because the speakers are so small, they need to be driven very hard to produce a useful volume level, so normal operation is near their design limits to begin with. Boosting it is useful for voice (such as audo books) but loud music (especially with loud low-frequency base) could potentially damage the speakers. And because small speakers are not good at producing low frequencies, users would be tempted to drive them even harder at low frequencies if given that option.

SUMMARY: For the safety of the speakers, it should be okay to boost the mid and high frequencies much more than low frequencies (which also makes spoken words more understandable).

If you want a warning, you should warn about boosting low frequencies too much. Again, that is dependent on what hardware protection is designed and programmed into the kindle fire.

[pruss]

How low is "low-frequency"?

I could set SpeakerBoost to not boost the lowest frequency, and then just boost the higher ones.

The central frequencies of the five equalizer bands on the Fire are:
60 Hz
230 Hz
910 Hz
3600 Hz
14000 Hz

Any advice on how to shape it for safe boosting?

I just tried not boosting the 60Hz at all, boosting the 230Hz at half of the user-specified level, boosting the 14000 Hz at 75% of the user-specified level, and boosting the others at the user-specified level. Voice was nice and clear.

[geekmaster]

Originally Posted by pruss

How low is "low-frequency"?

I could set SpeakerBoost to not boost the lowest frequency, and then just boost the higher ones.

The central frequencies of the five equalizer bands on the Fire are:
60 Hz
230 Hz
910 Hz
3600 Hz
14000 Hz

Any advice on how to shape it for safe boosting?

I just tried not boosting the 60Hz at all, boosting the 230Hz at half of the user-specified level, boosting the 14000 Hz at 75% of the user-specified level, and boosting the others at the user-specified level. Voice was nice and clear.

Without knowing how the kindle audio hardware and software is designed, we are really just guessing. If this were a company project, you might use a sacrificial kindle or two to see if and how you can damage it, and then keep your maximum settings well under those limits. If I worked at amazon and I had access to the kindle design specifications, I would set my limits to within the design limits of all the audio hardware components in the device.

With no "double-blind" testing to determine the cause of reported speaker damage, without potentially destructive testing, we can only guess at what are the safe limits.

EDIT: You could examine the speakers to determine their make and model, then lookup their specifications. Then you could attach instruments to measure the power (voltage and current) and the temperature of the voice coils, while driving it at various frequencies and amplitudes, with various waveforms (square wave being the most destructive). That would let you figure out what SOFTWARE settings will keep the speakers operating within their design maximum continuous operating range limits. Other than that, you could just let the end USER decide how loud is loud enough, with a disclaimer that any damage is not your problem if they overdrive their speakers to destruction.

[pruss]

Yeah, I have no time for testing and it doesn't make financial sense to destroy a Fire for a free app. Plus the app isn't just for the Fire.
I will leave it to the users, but I will by default shape the boost as above in the next release (in a few minutes).
A bit of googling hasn't actually turned up any Android user claiming destruction of speakers from any of the sound boost apps. (EDIT: See the two comments below--I've since found something.)

[geekmaster]

Originally Posted by pruss

A bit of googling hasn't actually turned up any Android user claiming destruction of speakers from any of the sound boost apps.

No google needed. A few posts back there is a claim that a user destroyed her speakers just by listening at high volume WITHOUT a sound boost app:

Originally Posted by Jessica Lares

You can destroy your speakers by just using the maximum volume the system has for long periods of time. I have done that in the past anyway. ...

If true, boosting the volume would increase the chances of that. But without enough reports of this from other users, you cannot make a reliable conclusion from the statistical insignificance of a small number of reports.

Speakers are shock sensitive. It is possible (perhaps likely) that the speakers were damaged by dropping the kindle (and the damage became worse with high volume levels). Shock damage can also occur by feeding high-impulse energy (full-volume clicks or pops) to the speakers (but the kindle hardware and firmware should compensate for that).

However, it makes perfect sense for you to set the DEFAULT values to a known-safe level, but allow the user to adjust the settings to any value the hardware provides (with adequate warning about loud volume levels causing possible damage to speakers, or to ears when wearing earphones). If somebody releases a slider at a level above your defined "safe" threshold, you could do an "are you sure?" popup with that warning...

[pruss]

Here's a user (go down to the leocut post) who says that his speakers gave out after using Volume+. He also says that vibration and notification LED gave out.