Designing a ringtone/notification sound that is audible from decent range and not easily muffled

Question

After finding out that most of the stock notification sounds in my phone are not satisfactory, I decided to make my own.

I aim to make a sound that is audible from decently long range and from inside of my pocket.

I know that lower frequency sounds travel further. But if it's too low, the speaker won't be able to produce it well or it won't register on my hearing. It can't be simply very loud, lest it would peak and get distorted and possibly ruin the speaker.

So, ignoring any artistic consideration, how would one design an ideal ringtone? One that can be heard from across the house, out of an average smartphone.

I know that most deciding factors are determined by the phone's software & hardware itself. So let's just say, the ringtone's going to be put in "an average smartphone".

Answer 1

How about a cyclic sine sweep?

Experiment to find the highest & lowest frequencies the phone can comfortably repro, then sweep between those 2, low to high then back again, then loop.
Pick a sweep frequency you wouldn't confuse with a passing fire/police/ambulance siren. There has to be some good reason they use sweeps too.

Late thought - you could actually do 3 versions - constant cycle, low to high & high to low, for 3 different purposes.

idk about other phones, but iPhone ringtones tend to peak at I think -10dB, so you can push a little bit on the volume without damage, but as you rightly point out, peaking near zero just goes quickly into distortion; doesn't sound good & actually doesn't feel as loud from a distance.

Alternatively - & this is what I use for my partner's ringtone - the telephone ring from the Keifer Sutherland show, 24, the one in their office at CTU. It changed each season but the early ones were the most distinctive. Fox used to have them freely available on their website, though I don't see them any more - but a quick Google tells me you can still pick up one or more versions for free.

For me, maybe it's just familiarity, I've had the same ringtone for her for over 10 years across many different phones, but it is one I can hear right through the house.

Music, snippets from songs etc., don't work well - they just seem to blend into the background too easily, especially if you've got the radio or tv on.
The only exception is if the music is very sparse. I use the opening 2 chords from The Clash, London Calling, for one of my ringtones & I can always hear that round the house where other tunes don't work - though I have been known to come dashing up to my work room to discover ...it was the radio.

Answer 2

Tetsujin's answer is good, and I know the idea is to design these sounds, but knowing human nature, human hearing and experiencing this myself, there is nothing that catches your attention and cuts through your soul like a baby screaming, crying. It fills quite a wide frequency range but is still distinctive. It's the perfect attention-grabber I'd say. Not very pleasant or likely to be actually used though.

Another thing to mention is processing the audio to get the perceived loudness as loud as possible without distortion. Things like compressors, maximizers and limiters will help with this.

Answer 3

I believe many of the good non-music ring tones are some variation of FM synthesis of few operators and some simple melody. It allows for a range of different tonalities that are still clean and not too noisy. The synth allows to place it to any range that one wishes e.g. to the "well audible range" of 1.5kHz-3kHz