FAQ — Real Questions, Honest Answers

Most people think a bigger or more expensive sub will solve the problem, but in 90% of cases it's not the subwoofer itself. It's simply not in the recording. I built the Mini SubHarmonics because I had that exact problem myself. My sub did nothing on older music. The Mini calculates in real time what should have been in the sub-bass region (10 to 40 Hz) and sends it to your subwoofer. Result: your sub finally does what you bought it for.

Test it yourself first: play a sweep from 100 Hz down to 20 Hz (there's a video of it on my site). Can you still hear it at 30 Hz? Good. Does it suddenly drop out? Then it's the sub itself, and buying a new one is the answer. But does it go deep enough yet you still miss the "punch"? Then it's the source material. That's exactly what the Mini SubHarmonics is built for.

It depends on where the problem sits. First, play a sweep from 100 Hz down to 20 Hz. If it drops out somewhere below 30 Hz, the issue is your subwoofer or speakers, and an upgrade there will make the biggest difference.

But in 90% of cases the problem isn't the system, it's the music itself. Most recordings simply don't contain frequencies below 50 Hz. A bass booster or EQ won't help in that case — there's nothing to boost. All you're doing is making the existing higher bass louder, which often just sounds muddy. The Mini SubHarmonics does something different: it generates the missing sub-bass in real time, based on what is in your music. You get real depth added, not amplified mud.

Yes, but differently than you're used to — and that's where the real difference lies. A regular bass boost (on your amplifier, in an EQ, or via a bass booster app) makes the existing bass in your music louder. More volume, often also more mud and distortion. And if there's nothing below 40 Hz in the recording, there's still nothing below 40 Hz after boosting — you just hear the higher bass frequencies louder, often muddier.

The Mini SubHarmonics works fundamentally differently: it generates new sub-bass tones (10–40 Hz) that were never there, and mixes them in a controlled way. Hear 80 Hz in the music? It adds 40 Hz. Hear 60 Hz? It adds 30 Hz. The effect people search "bass boost" for — more and deeper bass you hear and feel in your hi-fi setup — you absolutely get. But clean, without distortion, and working even on music where regular boost has no effect.

Sub-bass is everything below 60 Hz. The part of the sound you feel more than you hear: an organ pedal in a church, a film explosion that hits you in the chest, an 808-drop in electronic music, the physical thump of a large kick drum.

Sub-bass has roughly two regions. Between 40 and 60 Hz is the "punch" — clearly audible, and where most decent subwoofers and larger speakers still perform well. Between 10 and 40 Hz is the "rumble" — where hearing turns into feeling, and where most systems (and most recordings) drop out.

Most music is missing exactly that deepest portion. Not because it's bad music, but because those frequencies were never captured during recording. The Mini SubHarmonics restores that range, targeting 10 to 40 Hz.

Almost any active (powered) subwoofer with a line-level RCA input works. The Mini connects between your pre-out — from your amplifier, preamp or AV receiver — and the RCA input of your subwoofer. No drivers, no software, just route the signal through it.

What your sub does need to do is go low enough to reproduce the generated frequencies. A subwoofer that already collapses at 40 Hz won't produce 25 Hz, even when the Mini SubHarmonics sends those signals to it. Test first with a sweep from 100 Hz down to 20 Hz (video on the site): can you still hear or feel something at 30 Hz? Then your sub is compatible, and the difference will be clearly audible.

A passive subwoofer (without its own amplifier) won't work directly — it needs a separate amplifier first. Same goes for speakers with only speaker-cable inputs.

A bass booster makes existing bass louder. If there's nothing below 40 Hz in your music, there's still nothing after boosting. The bass just gets thick and muddy, no real depth. A subharmonic processor like the Mini creates new tones, one octave below what's already there. Hear 80 Hz? I generate 40 Hz alongside it. Hear 60 Hz? I add 30 Hz. So you get real depth instead of amplified mud.

Yes, often you can. A good sub from a few years ago can technically reproduce sub-bass just fine, it's just not in the source. For €199 you add the missing frequencies, instead of spending hundreds of euros on a new sub that with the same source content still won't go deep. Trying this first is smart. If it doesn't work for your setup, just send it back via the Marktplaats buyer protection.

Yes, that's actually a very elegant solution technically. Do you have a preamplifier with two pre-outs, or a separate sub-out? Send one to your regular amplifier (clean signal, nothing changed) and route the other through the Mini SubHarmonics to your active subwoofer. That way your main signal stays completely clean and the subharmonic only affects the sub. Works fine as long as it stays at line level.

That's where it really shines. Tape recorders from the '70s and '80s lost almost everything below 50 Hz. Not because the music didn't have it, but because the technology couldn't capture it. Many classic albums are "empty" in the sub-bass region as a result. The Mini gives those albums back what they never had.

With turntables there is something to keep in mind though. A stylus in a groove always generates some rumble, especially below 30 Hz. That rumble is already in your signal, and the Mini SubHarmonics amplifies it along with everything else. That doesn't sound right, you get a thud in your sub that has nothing to do with the music.

The solution is simple: filter everything below 40 Hz with an EQ before the Mini SubHarmonics. The rumble disappears and the Mini then generates clean, new sub-bass based on what's actually in the music. So you get the best of both worlds: vinyl enjoyment without rumble, with the depth the recording itself never had.

With CD, streaming and digital sources you don't have this problem. There's no mechanical rumble there, so you can connect the Mini directly without a pre-filter.

True, dbx pioneered this technology. But those old analog circuits added audible coloration and noise. Quite charming for some hi-fi romantics, but not pure. The Mini SubHarmonics does the same principle with modern DSP technology: cleaner, quieter (-83 dB noise floor), and suitable for high-end systems. No vintage charm, but a transparent signal path.

In an orchestra: timpani, organ pedals, five-string double bass. In modern music: 808s, synth bass, sub-drops in electronic music. And in films: the entire LFE channel (explosions, door slams, rumble). But it's not just about what you can hear below 50 Hz, it's also about what you can feel. A lot of sub-bass registers in your body before your ears pick it up. That's what most music is missing.

Yes, films benefit enormously from it. An AV receiver with a line-level pre-out for the subwoofer is ideal. Put the Mini in between and you get sub-bass down to 10 Hz where your film normally only reaches 40 Hz. Older films notice the difference the most. Make sure your sub and amplifier can also reproduce those frequencies, otherwise you're generating something you can't hear.

A DSP Subharmonic Synthesizer is hardware that uses digital signal processing to create new sub-bass tones based on what's already in your music. For each detected low frequency, the device generates a tone exactly one octave lower, mathematically precise and phase-aligned. The Mini SubHarmonics is my version of it: handmade in the Netherlands, in small batches, for €199.

Hans Beekhuyzen (105,000+ subscribers on YouTube) tested the Mini in his reference setup. His conclusion was that the music sounded "more live, more evolving". There are also several buyer reviews via Marktplaats and Ebay, readable on the order page. To date, not a single unit has been returned.

The Mini SubHarmonics itself (aluminium 70×60×30 mm), an EU power adapter, a 12V car cable, and a quick start guide. Everything you need. Connect via stereo RCA and you're ready. No software, no drivers, no account to create.

Yes, there are excellent software versions and plugins for generating subharmonic frequencies. But we chose hardware, and that's a deliberate choice. Software plugins always have latency, drivers and updates. They only work in one playback chain (Roon, your DAW, your phone app). Hardware works everywhere: streamer, CD player, turntable, AV receiver, anything with line-level RCA outputs. Connect once and you're done. No subscription, no "supported until 2027", no incompatible OS updates that break everything.

This is the question I designed the Mini SubHarmonics for. In most hi-fi setups the problem isn't the sub or the amplifier, but the music itself. Many recordings simply don't contain frequencies below 50 Hz. A new sub isn't going to fix that. The Mini SubHarmonics calculates the missing sub-bass in real time and sends it to your existing sub. For €199 you get deeper bass out of the same system. With audiophile setups the difference is most noticeable, because the rest of the chain is already clean and transparent.

That's a fair question, and the answer is: both. The deep bass you actually hear sits roughly between 25 and 40 Hz. Below that, you feel it more than you hear it. An organ pedal in a church, a film explosion you feel in your chest, a bassline that makes the room come alive. That's the physical side of bass that most music is missing. The Mini SubHarmonics adds exactly the deep low end your system is ready for. Not for nice measurement graphs, but for the feeling that music finally moves you the way it should.