Using Spek to see if an audio file is really lossless after doing noise reduction.

What program are you using for noise reduction?

Goldwave (clipboard)

To answer my own question, I now see that Goldwave noise reduction has many parameters that I don’t completely understand. Each one ends up influencing the results on Spek, so I’ll have to try different settings of Scale, Overlap, FFT size, etc., to make things work.

That doesn't surprise me. I use an older version of Adobe Audition for LP transfers and other audio editing work (though I don't do much these days) and the level of complexity and number of settings in these programs can be staggering.

I am a semi-professional audio restoration technician. I have for close to two decades used the following programs-

iZotopeRx Advanced- unparalleled at removing static and impulsive disturbances, some quite gross in nature.

Pristine Sounds 2005- great for spot-clean up

Sound Forge- best all-round digital audio editor lets me perform magic on audio

Acoustica Advanced- has a "remix" function that lets me dodge around some problems.

I am a semi-professional audio restoration technician.

I hear bright noises from speakers in below. Why the bright noise? Can you make it better?

Acora speaker

Similar noise on the left speaker below.

https://youtu.be/IHf_FSa8amE?si=V9rQePsCBUEkBD8O

Alex/Wavetouch audio