Hi! I am Ivan and I live in Warsaw. On this page I am writing about acoustics, loudspeakers and programming. I'm working as a full-stack developer for Visual Watermark, Watermarkly and PDF Unlimited.

React vs Preact vs Inferno

React is an excellent web development framework. It allows one to develop a web app very quickly compared to imperative frameworks. Unfortunately, faster development has a cost: performance. React-based app perform a lot of calculations and does a lot of memory allocations. The more complex UI app has, the more CPU and RAM it uses. This is true for both declarative and imperative frameworks, but with React, CPU requirements grow faster.

PayPro Global vs FastSpring Conversion Rate

My day job is selling software I make. I used FastSpring as my payment processor for about 12 years. Unfortunately, in past two years the support became almost non-existent. For example, when the payment system stops sending licenses to clients, I got it reviewed and fixed in a week. That’s not acceptable in my opinion and I decided to look for other options. PayPro Global’s was very responsive in responding to my questions.

Open Baffle vs Closed Box

Last year I built an open baffle speaker using horn and 12” PA driver. Generally, it sounded good, but I always wondered how they would sound in a closed box or bass-reflex enclosure. Closed box also allows me to place the speaker near front wall and save some space in the center of my living room. For dancing ;) I ordered two boxes of the same height as my open-baffle speakers.

Is Chromecast Audio Bit-Perfect?

I had difficulties getting asleep during lockdown. In order not to waste time in vain, I decided to check if Chromecast Audio is bitperfect or not. I used an Apple laptop and an external sound card “Audiotrack Maya U5” as a test stand. The soundcard is quite cheap, but it has a digital input, which we will need for this test. Validating Correctness Of The Test To check the correctness of the test, I connected the optical output of the sound card to its optical input.

Making Active Loudspeakers Using EqualizerAPO

I would like to bring up the topic of active crossovers. This is a very convenient thing that allows you to quickly change filter settings and try different configurations without soldering new crossovers. In addition, the sound quality of the active crossover is a bit higher than that of the passive crossover on average components - it gives a more predictable and a more transparent result. For the active crossover, we can use external tools or software on our own computer.

Open Baffle Speaker With Horn Compression Driver. RCF ND950 / Beyma 12mwnd drivers.

Project Goal I wanted a pair of loudspeakers that will work well in a normal living room without special acoustic treatement. I live in a beautiful apartment. Unfortunately, the room is quite lively. The room has painted walls, wooden floors and leather furniture. Upholstered furniture is not an option yet, because I have two small kids. It is very comfortable appartment to live in, but the sound is a bit lively to my taste.

One Or Two Subwoofers?

I believe that two (or more) smaller, cheaper subwoofers are better than one large and more expensive subwoofer. I’ll prove it with measurements. Below I present the spectrogram of one subwoofer, placed in the front right corner of my room. The spectrogram shows how quickly individual frequencies fade away. In a perfect room, each frequency fades out after exactly one wavelength. E.g. the 20Hz wave must fully disappear after 50ms, the 100Hz wave must disappear after 10ms.

About Me

Hi! I am Ivan - a software developer who loves music and is interested in acoustics. I’m lazy to do routine work every day, so I figure out how to optimize it. It pisses me off when application runs slow, so I look for why and correct it. I always say “Yes!” when someone asks me if i can do it. Then I go looking for a solution on StackOverflow;)