EaglePlayer Brings 15-bit Paula High Fidelity Sound!

EaglePlayer, the most comprehensive music player on Amiga since the 90s, is back. Version 2.07b just landed on Aminet, and the headline feature is sound: significantly better sound, even from Paula.

Yes, Paula. The 8-bit chip from 1985. Read on how you can get High Fidelity sound using just Paula etc,…!

So how can 8-bit become 15-bit? Let’s explain, because there is confusion!

Paula has four 8-bit channels. Classic Amiga could play 8-bit samples. But since early 90s, we know Paula can do more. The trick is called 14-bit playback, and it has nothing to do with the AHI hack. Paula is capable of doing this!

Paula’s volume register is 6-bit, values 0 to 64. If you play two channels perfectly synced with same period:

Channel 0 plays the high 8 bits of a 16-bit sample at volume 64
Channel 1 plays the low 8 bits at volume 1

In analog mixing inside Amiga, those two signals add: 64_high + 1_low. That gives 14-bit dynamic range. Two channels become one high-quality channel. That means stereo 15-bit uses all four Paula channels.

This technique existed before — Play16 on Aminet, AHI’s 14-bit mode. But implementation matters. Amitopia will make a full review of the 15-bit achievement.

Hardware is however 14-bit. The extra bit is perceptual, from the new highboost EQ filter that comes with EaglePlayer 2.07.

Every Amiga has a lowpass filter after Paula to smooth 8-bit steps, but it kills highs early. EaglePlayer’s highboost compensates it, giving flat response up to 18kHz at both 28kHz and 44kHz mixing.

Flat highs = ∼6dB more clarity = roughly one extra bit to your ears. That’s why readme says 15-bit quality from 14-bit Paula — calibrated 14-bit + correct EQ, without the need of AHI. Actually using AHI on Paula isn’t the best option at all. AHI is way better for soundcards connected to Zorro, PCI or the PCMCIA slot of your Classic Amiga.

Result: Any Amiga 1200 in Bergen or elsewhere gets clean, high-fidelity playback straight from Paula. With FFT Analyzer now also in P96 High/True Color with AMMX acceleration.

What EaglePlayer 2.07 fixed

Previous EaglePlayer default calibration was actually closer to 13.5-bit, not true 14-bit. Author Jan Blumenthal and Henryk Richter rewrote the amplifier for 2.07 version:

New 14-bit table: Way better defaults for uncalibrated systems. Fixed old C. Buchner quantization approach that created unnecessary artifacts.
Stereo 14-bit calibration: You can now calibrate left and right separately for true 14-bit.
Noise shaping: Optional 16-bit to 14-bit conversion with noise shaping on 68060 or faster, pushes quantization noise above hearing range.
Amiga 600/Amiga 1200 autodetection: Amiga ECS and Amiga AGA chipsets have different lowpass audio filters than OCS Amigas. EaglePlayer now detects the Amiga 1200 if you have it and adjusts highboost EQ automatically.
28kHz limit on OCS: Automatic limitation to 28kHz sampling on OCS and non-doublescan modes to avoid DMA issues.

Download: EaglePlayer 2.07 from the author website bax.comlab.uni-rostock.de — EaglePlayer is free, m68k, no AHI required.

Thirty years later, Paula still surprises — all by herself. Will we reach Paula 16-bit at some point? … I wouldn’t be surprised. However.. I recommend any Amigans to get EaglePlayer. It’s a remarkable player with so many options. Its a really awesome player that other platformers should envy.