Fidelia 2 — the Mac audiophile player, rebuilt from scratch (Audio Unit hosting, bit-perfect, no subscription)

[pkrekelb]

Developer here — Patrick Krekelberg, Audiofile Engineering (audiofile.engineering). Per the forum's developer guidelines, flagging up front that this is my app.

Fidelia is the Mac audiophile player we first shipped in 2011 (Macworld covered the launch). It nearly died in the consolidation that took most small-shop Mac audio apps — instead I rebuilt it from the first line of code: new realtime engine, bit-perfect and gapless playback, headphone DSP (frequency-dependent crossfeed) and psychoacoustic dither built in, and three Audio Unit slots that host your own plugins out-of-process inside the App Store sandbox. A crashing plugin can't take playback down — very few players even attempt AU hosting inside a sandboxed Mac App Store app, because the AU contract predates the sandbox by a decade.

Free 14-day trial, one-time unlock, no subscription.

I wrote up the rebuild — the war stories, the sandboxed-AU-hosting fights, and how one person keeps a commercial Mac audio catalog alive now: https://audiofile.engineering/notes/rebuilding-fidelia

App Store: https://apps.apple.com/us/app/fidelia/id416135376

Worth stating plainly up front: this was an agent-assisted rebuild, and I directed all of it. AI-assisted development is standard practice now in professional software and has been for years. I've been a software/audio engineer and product developer for 25+ years, with seven issued patents, and every architecture, DSP, and shipping decision here is mine to stand behind. The agents were a force multiplier, not the author; the linked essay is candid about exactly how it worked.

Happy to answer anything about the rebuild, signal chain, or the AU hosting.

Cheers all,
Patrick

 

[leifp]

I look forward to giving this a stab! Writing on the iPad while travelling, so hopefully will think of this when I’m Mac-bound again. Hence why I’m writing at all; the memory that is macrumors…

 

[pkrekelb]

I look forward to giving this a stab! Writing on the iPad while travelling, so hopefully will think of this when I’m Mac-bound again. Hence why I’m writing at all; the memory that is macrumors…

Sounds good! It will be great to hear what you think of Fidelia.

 

[leifp]

it seems to take me to Fidelia 1 (unless 2 is your internal metric) or perhaps it doesn’t want to release it in Canada? Your Audiofile Engineering page takes me to two apps for Mac: Fidelia and Audiofile DDP. What am I missing?

 

[pkrekelb]

it seems to take me to Fidelia 1 (unless 2 is your internal metric) or perhaps it doesn’t want to release it in Canada? Your Audiofile Engineering page takes me to two apps for Mac: Fidelia and Audiofile DDP. What am I missing?

Fidelia is available worldwide. As of this writing, the App Store has Fidelia 2.8.8. With that said, it is written for macOS 14 so if you’re on macOS 13 or earlier you will see 1.x on the listing. Is that the case?

 

[leifp]

Okay, it was the page itself that’s the problem, or PEBKAC. I’m of a generation where having a version number is part of the name of the software. The App Store page has 2.8.8 buried, lists it as 4+ years old, and has comments dating from 2-3 years ago. Disconcerting. (To me, obviously)

 

[pkrekelb]

The App Store page has 2.8.8 buried, lists it as 4+ years old, and has comments dating from 2-3 years ago. Disconcerting. (To me, obviously)

In App Store listings, the "4+" is an age rating. 4+ simply means "Apps in this category contain no objectionable material". Yes, there are reviews from the long history of Fidelia, just like you would find on any long-running app such as Logic Pro, but many recent reviews as well; just sort them by Most Recent if you like.

 

[turbineseaplane]

So a whole bunch of AI was used.

It's disingenuous to not put that in your main post here and instead bury it in the blog post you linked.

Look at ALL these tags you added 👇 ... but not one of them is "agents", or "built with AI" or even just "AI"

 

[pkrekelb]

It wasn't buried — the writeup I linked lays out exactly how Fidelia was rebuilt, agents and all; I just led with what the app does rather than how it was made. But it's fair that it belongs in the post too, so I've added a line up top.

The one thing I'll stand on: the tooling doesn't get the result a pass — and it doesn't get it a penalty either. The realtime engine, the bit-perfect path, the headphone DSP, the sandboxed AU hosting hold up under scrutiny or they don't, and I'm glad to go deep on any of them here. Shipped code has to earn its keep whether it's hand-typed, agent-assisted, written by an outsourced team, or built on a licensed framework — none of which anyone typically discloses, and nobody asks them to. That's the part worth kicking around. For what it's worth, customers have been living with the update happily since it shipped in April.

Appreciate the engagement.

 

[pkrekelb]

Here is the album view we've been refining behind the scenes for quite awhile, now available in Fidelia 2.9.x. We've kept it understated and tailored, with a bit of subtle animation flourish, and a new dismissible "now playing" panel right in the Library with Fidelia Remote style controls. It's meant to feel like flipping through records. I welcome your feedback.

The current signal path is readily accessible:

 

[turbineseaplane]

It wasn't buried — the writeup I linked lays out exactly how Fidelia was rebuilt, agents and all; I just led with what the app does rather than how it was made. But it's fair that it belongs in the post too, so I've added a line up top.

The one thing I'll stand on: the tooling doesn't get the result a pass — and it doesn't get it a penalty either. The realtime engine, the bit-perfect path, the headphone DSP, the sandboxed AU hosting hold up under scrutiny or they don't, and I'm glad to go deep on any of them here. Shipped code has to earn its keep whether it's hand-typed, agent-assisted, written by an outsourced team, or built on a licensed framework — none of which anyone typically discloses, and nobody asks them to. That's the part worth kicking around. For what it's worth, customers have been living with the update happily since it shipped in April.

Appreciate the engagement.

Read the room on AI
You're too well spoken to not know better.

Talk around it all you want and dismiss concerns about it - fine.
Just be upfront about it in the future please.

 

[pkrekelb]

One of the most useful aspects of Fidelia going back over its 15-year history has been the AudioUnit slots. Mix and mastering engineers and high-end speaker and equipment manufacturers worldwide use it to audition mixes through specific plugin chains. Mac audio developers will know how delicate AU hosting can be, particularly in sandboxed (App Store) apps. We're shoehorning artifacts from a decades-old standard into a modern context - licensing, file access, binary signing, everything is on the table.

Building on this legacy, literally hundreds, very probably thousands of hours of development, we now support more plugin configurations than we ever have before. We routinely run chains including UAD, Strymon, Moog, Native Instruments, iZotope, Slate, Melda, KiloHearts, Audiothing and many others, with full support. I would go so far as to say if you find a plugin we don't support out of the box, write to us at support@audiofile.engineering and I will personally investigate. I appreciate the challenge!

Cheers, all

 

[pkrekelb]

Hey, it took 15 years but better late than never, right?

Fidelia now plays live internet radio stations. The "Streamside" bar is auto-organized by station tag and drag/drop re-positionable. Stations can be assigned a "preset" to make it easy to play a given station via ^1 - ^9 or the keypad on the free iPhone remote. The stream is routed through the same Audiofile Engine as local files - so you can play bit-perfect or include in the signal chain your own plugins and Audiofile HeadSpace headphone processing.

We'd love to hear your feedback. Cheers.

 

[mudflap]

Did you read the actual post? It can't get more up front than that.

Read the room on AI
You're too well spoken to not know better.

Talk around it all you want and dismiss concerns about it - fine.
Just be upfront about it in the future please.

 

[Iridescent Caterpillar]

I think the posts by OP are just more AI slop, no actual communication from him just spouting different marketing copy in each new post.

Totally disingenuous "developer". Not even worth checking more into this app.

 

[pkrekelb]

I am happy to answer any questions, @Iridescent Caterpillar, and I apologize if my normal manner of writing is too formal for you. It's challenging as a family-owned company to set aside time for forum posts as I generally need to focus on engineering and product development as well as customer support.

If you'd prefer a slick investor-backed or big corporate business with a marketing staff and a big-ticket subscription fee, then you're welcome to look elsewhere. I am sure they would be much better at their macrumors posts, but that's not my scene.

If you like, we can have a livestream to run through anything you'd like to know about Fidelia and the Audiofile engine. Cheers.

 

[pkrekelb]

Apple seems to be of the opinion that Fidelia is not all that bad: