I have written a number of articles on Hackernoon regarding AI and empathy. In this article I move beyond the primarily text oriented approach I have taken in the past to address voice output. I also move beyond empathy to the broader space of emotional expression. articles on Hackernoon regarding AI and empathy The article investigates the performance of several text-to-speech engines (Eleven Labs, Hume, iCednant Speech, Speechify) in terms of both speed and quality when generating emotionally laded speech. Several major brands like Amazon, Google, Microsoft were not evaluated because either their platforms made accessing the API complex or they did not offer direct emotional nuance, e.g. SSML had to be used (See below). All the evaluated engines are fine for short form converting input from both a speed and quality perspective, i.e. just one sentence where there is not much opportunity for emotional nuance. From a quality perspective they are all also fine for longer form input where emotional nuance may not be critical, e.g. reading a business document. Although for long form, the speed to generate the audio can vary dramatically. However, dramatic differences appear when the engine are faced with the nuanced medium to long form formats of poetry, meditation, and coaching . The article isn’t very long because its focus in audio; hence, you will spend more time listening that you do reading. Also, by way of disclosure, I have a financial interest in the success of some of the platforms covered, so I won’t be doing any qualitative comparisons. I will be leaving it up to you the reader listener to decide which engines perform best under which scenarios. I will restrict comparisons to quantitative values such as speed and cost. reader A note about SSML … Although SSML appears quite powerful on its face, particularly when used with the contour attribute that allows for changing frequency and volume at specific millisecond offsets, at the end of the day it does not come close to simuating real human emotion. The micro prosody required can only be matched by neural processors. However, some SSML does make for better management of pauses, volume and special pronunciations. Also note, iCendant is partnered with Speechify to enhance their capability. Speechify really shines in the editing space. It relatively new to the real-time API space and iCendant gives the Speechify platform a lift. Poetry Poetry is a hard domain to get right given it’s varying volume, cadence, and emotion, along with dependence on line breaks and alternative grammatical structures for emphasis. Follow along with the text as you listen to the audio from each vendor. After A Great Pain - by Emily Dickinson After great pain, a formal feeling comesThe Nerves sit ceremonious, like TombsThe stiff Heart questions 'was it He, that bore,'And 'Yesterday, or Centuries before'?The Feet, mechanical, go roundA Wooden wayOf Ground, or Air, or OughtRegardless grown,A Quartz contentment, like a stoneThis is the Hour of LeadRemembered, if outlived,As Freezing persons, recollect the SnowFirst Chill then Stupor then the letting go After great pain, a formal feeling comesThe Nerves sit ceremonious, like TombsThe stiff Heart questions 'was it He, that bore,'And 'Yesterday, or Centuries before'?The Feet, mechanical, go roundA Wooden wayOf Ground, or Air, or OughtRegardless grown,A Quartz contentment, like a stoneThis is the Hour of LeadRemembered, if outlived,As Freezing persons, recollect the SnowFirst Chill then Stupor then the letting go Platform Time To Generate Audio ElevenLabs 5s 🔊 Hume 13s 🔊 iCendant Speech 5s 🔊 Speechify 3s 🔊 Platform Time To Generate Audio ElevenLabs 5s 🔊 Hume 13s 🔊 iCendant Speech 5s 🔊 Speechify 3s 🔊 Platform Time To Generate Audio Platform Platform Time To Generate Time To Generate Audio Audio ElevenLabs 5s 🔊 ElevenLabs ElevenLabs 5s 5s 🔊 🔊 🔊 Hume 13s 🔊 Hume Hume 13s 13s 🔊 🔊 🔊 iCendant Speech 5s 🔊 iCendant Speech iCendant Speech 5s 5s 🔊 🔊 🔊 Speechify 3s 🔊 Speechify Speechify 3s 3s 🔊 🔊 🔊 Coaching Coaching is a hard domain to get right given it’s need for potentially abrupt emotional, speed and volume transitions while also taking into account empathy. Volleyball Pep Talk - Generated by Claude Sonnet 3.5 Team, gather around.Consider yourself. Those hands have served thousands of sets.Those legs have jumped for countless blocks.Those lungs have powered through five-set matches when you thought you couldn't go on.But volleyball isn't played with hands or legs or lungs alone.It's played with heart.Today, we face the toughest opponent of our season.They're taller. They're ranked higher.The statistics say you shouldn't win.But statistics can't measure teamwork.Remember who we are.You are not just six individuals on a court - you are a single unit that breathes, moves, and fights as one. When you step onto that court, you carry each other's dreams.I've watched you grow from a group of talented players into something extraordinary.In those moments when fatigue sets in, when doubt creeps into your mind, remember why you play.Remember the joy of a perfect pass, the satisfaction of a clean kill, the electric feeling when you celebrate together.Play with passion. Play with purpose. Play for each other. Team, gather around.Consider yourself. Those hands have served thousands of sets.Those legs have jumped for countless blocks.Those lungs have powered through five-set matches when you thought you couldn't go on.But volleyball isn't played with hands or legs or lungs alone.It's played with heart.Today, we face the toughest opponent of our season.They're taller. They're ranked higher.The statistics say you shouldn't win.But statistics can't measure teamwork.Remember who we are.You are not just six individuals on a court - you are a single unit that breathes, moves, and fights as one. When you step onto that court, you carry each other's dreams.I've watched you grow from a group of talented players into something extraordinary.In those moments when fatigue sets in, when doubt creeps into your mind, remember why you play.Remember the joy of a perfect pass, the satisfaction of a clean kill, the electric feeling when you celebrate together.Play with passion. Play with purpose. Play for each other. Platform Time To Generate Audio ElevenLabs 5s 🔊 Hume 20s 🔊 iCendant Speech 4s 🔊 Speechify 3s 🔊 Platform Time To Generate Audio ElevenLabs 5s 🔊 Hume 20s 🔊 iCendant Speech 4s 🔊 Speechify 3s 🔊 Platform Time To Generate Audio Platform Platform Time To Generate Time To Generate Audio Audio ElevenLabs 5s 🔊 ElevenLabs ElevenLabs 5s 5s 🔊 🔊 🔊 Hume 20s 🔊 Hume Hume 20s 20s 🔊 🔊 🔊 iCendant Speech 4s 🔊 iCendant Speech iCendant Speech 4s 4s 🔊 🔊 🔊 Speechify 3s 🔊 Speechify Speechify 3s 3s 🔊 🔊 🔊 Meditation Meditation is a hard domain to get right given it’s need for cadence, counting and smooth emotional transitions. I suggest that while listenting to the meditations you focus on breathing from your belly and closing your eyes. Breathing Meditation - Generated by Claude Sonnect v3.5 We will be doing a calming exercise, breathe deeply through your nose, hold, then exhale making a whooshing sound.Inhale life 1... 2...Hold peace 1... 2... 3...Exhale tension 1... 2... 3... 4...Repeat...Inhale... 1... 2... 3...Hold... 1... 2... 3... 4...Exhale... 1... 2... 3... 4... 5...And finally...Inhale... 1... 2... 3... 4...Hold... 1... 2... 3... 4... 5...Exhale... 1... 2... 3... 4... 5... 6...May your life be full of peace.May your tensions be taken by the wind whispering in the trees. We will be doing a calming exercise, breathe deeply through your nose, hold, then exhale making a whooshing sound.Inhale life 1... 2...Hold peace 1... 2... 3...Exhale tension 1... 2... 3... 4...Repeat...Inhale... 1... 2... 3...Hold... 1... 2... 3... 4...Exhale... 1... 2... 3... 4... 5...And finally...Inhale... 1... 2... 3... 4...Hold... 1... 2... 3... 4... 5...Exhale... 1... 2... 3... 4... 5... 6...May your life be full of peace.May your tensions be taken by the wind whispering in the trees. Platform Time To Generate Audio ElevenLabs 5s 🔊 Hume 12- 20s 🔊 iCendant Speech 5s 🔊 Speechify 3s 🔊 Platform Time To Generate Audio ElevenLabs 5s 🔊 Hume 12- 20s 🔊 iCendant Speech 5s 🔊 Speechify 3s 🔊 Platform Time To Generate Audio Platform Platform Time To Generate Time To Generate Audio Audio ElevenLabs 5s 🔊 ElevenLabs ElevenLabs 5s 5s 🔊 🔊 🔊 Hume 12- 20s 🔊 Hume Hume 12- 20s 12- 20s 🔊 🔊 🔊 iCendant Speech 5s 🔊 iCendant Speech iCendant Speech 5s 5s 🔊 🔊 🔊 Speechify 3s 🔊 Speechify Speechify 3s 3s 🔊 🔊 🔊 Costs And Other Info Platform Cost (approximately 1,000 char per minute) SSML Available ElevenLabs $0 to $1,300 per month including fixed usage2,000 to 22,000 minutes (20,000 to 222,000 chars)$0.016 to $0.012 per 1,000 chars No(limited custom XML) Hume $0 to $900 per month including capped usage with overage fees10,000 to 10,000,00 characters per month$0.20 to $0.10 per 1,000 chars overage No iCendant Speech $0.008 per 1,000 chars + $10 per month No Speechify $0.001 per 1,000 chars Yes(moderate emotion extensions) Google Neural $0.016 per 1,000 chars (not evaluated due to limited emotions in extended SSML) Yes(very limited emotion extensions) Platform Cost (approximately 1,000 char per minute) SSML Available ElevenLabs $0 to $1,300 per month including fixed usage2,000 to 22,000 minutes (20,000 to 222,000 chars)$0.016 to $0.012 per 1,000 chars No(limited custom XML) Hume $0 to $900 per month including capped usage with overage fees10,000 to 10,000,00 characters per month$0.20 to $0.10 per 1,000 chars overage No iCendant Speech $0.008 per 1,000 chars + $10 per month No Speechify $0.001 per 1,000 chars Yes(moderate emotion extensions) Google Neural $0.016 per 1,000 chars (not evaluated due to limited emotions in extended SSML) Yes(very limited emotion extensions) Platform Cost (approximately 1,000 char per minute) SSML Available Platform Platform Cost (approximately 1,000 char per minute) Cost (approximately 1,000 char per minute) SSML Available SSML Available ElevenLabs $0 to $1,300 per month including fixed usage2,000 to 22,000 minutes (20,000 to 222,000 chars)$0.016 to $0.012 per 1,000 chars No(limited custom XML) ElevenLabs ElevenLabs $0 to $1,300 per month including fixed usage2,000 to 22,000 minutes (20,000 to 222,000 chars)$0.016 to $0.012 per 1,000 chars $0 to $1,300 per month including fixed usage2,000 to 22,000 minutes (20,000 to 222,000 chars)$0.016 to $0.012 per 1,000 chars No(limited custom XML) No(limited custom XML) Hume $0 to $900 per month including capped usage with overage fees10,000 to 10,000,00 characters per month$0.20 to $0.10 per 1,000 chars overage No Hume Hume $0 to $900 per month including capped usage with overage fees10,000 to 10,000,00 characters per month$0.20 to $0.10 per 1,000 chars overage $0 to $900 per month including capped usage with overage fees10,000 to 10,000,00 characters per month$0.20 to $0.10 per 1,000 chars overage No No iCendant Speech $0.008 per 1,000 chars + $10 per month No iCendant Speech iCendant Speech $0.008 per 1,000 chars + $10 per month $0.008 per 1,000 chars + $10 per month No No Speechify $0.001 per 1,000 chars Yes(moderate emotion extensions) Speechify Speechify $0.001 per 1,000 chars $0.001 per 1,000 chars Yes(moderate emotion extensions) Yes(moderate emotion extensions) Google Neural $0.016 per 1,000 chars (not evaluated due to limited emotions in extended SSML) Yes(very limited emotion extensions) Google Neural Google Neural $0.016 per 1,000 chars (not evaluated due to limited emotions in extended SSML) $0.016 per 1,000 chars (not evaluated due to limited emotions in extended SSML) Yes(very limited emotion extensions) Yes(very limited emotion extensions) Conclusion Hume seems awfully expensive compared to the other options, particularly given its slower speed. Ultimately, it is not clear any of the platforms can currently handle all needs, although I see promise at the intersection of all their capabilities. Another 12 months I think … Vested interest disclosure: the author is a part owner of iCendant Speech. Vested interest disclosure: the author is a part owner of iCendant Speech. Vested interest disclosure: the author is a part owner of iCendant Speech. Vested interest disclosure: the author is a part owner of iCendant Speech.
