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.

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;)