High End Subwoofer 20 – 100 Hz ENG



The project was created for a friend. Initially, there were attempts to buy the factory subwoofer, but finding a subwoofer with desirable characteristics as good prices happened after simply not realistic, came the decision to design Super Subwoofer.


Design intent:

  • very low lower frequency range below 20 Hz
  • very good impulse response.

As we care for the very good impulse response design was based on a closed box! This resulted in That the size of the housing is simply a large external dimensions are 1.1 x 0.62 x 0.41 m and a total gross volume of 0.279 m3 (279L) brutto and netto 180 liters. As a speaker was chosen mighty Dayton RSS390HF. To drive the whole amplifier was used HYPEX DS4 reflected a near 400 W into 4 ohms (actually some 320W). Although I Consider That it is not too strong in the clean 500W inches would not hurt, of course, the amplifier operates in class D. Enclosure speaker, of course, been properly calculated .

It was used for the construction of MDF with a thickness of 38mm with additional reinforcements in the middle.

The whole was then finished wood veneer.


Speaker RSS390HF-4 specification:

rss390hf-4_spec_1 rss390hf-4_spec_2

rss390hf-4_spec_4 rss390hf-4_spec_3


Simulation and calculation of the enclosure speaker.

The simulation using the software AJ Sealed Design 2.0


and simulation using on the web site: WEB


Closed BOX was chosen due to the best transient response and closed BOX gives you the best group delay – see charts above.

On this basis, the casing is made with a volume of 180 liters. As can be seen the housing has MATRIX structure and is totally internally ribbed for maximum rigidity. The chamber of the amplifier is completely isolated from the remainder of the housing.

Figure construction – housing. (PDF – Click)


A few photos same mechanical design

sub_5 sub_4

sub_3  sub_2

and final construction:

sub_10 sub_6

sub_7 sub_8


Subwoofer is a big power 🙂 …

Unfortunately, not too large rooms at such low frequencies there is the problem of standing waves and pneumatic pumping air. To „Column” developed their full potential the room in which it resides should have considerable dimensions. It’s probably the only „serious” problems.

Speaker used has an aluminum diaphragm so you need to absolutely cut off frequencies above 200Hz, otherwise we will hear from the membrane Shading unpleasant metallic sound (there are resonances). So stanchion best to control the signal output from the SUB receiver. Another reasonable question is to achieve „sync” phase between the main speakers and subwoofer present. Of course, this requires some fun and experience, fortunately Hypex-amplifier has a fairly extensive regulatory capabilities (including full – continuous phase adjustment, cutoff frequency, etc.), so it should not be a problem. However, we must remember that never perfect fazowości not keep (smoothly it will change as a function of frequency), so bandwidth „from above” should be as minimal and tailored to the main speakers in the other case we have a „hole” in the passband.
And finally a weight of about 120 kG 🙂


Notes / documentation / links :

  1. Hypex DS 4.0 Class D Amplifier
  2. AJ Saled Design Software
  3. Online Loudspeaker Enclosure Calculation
  4. Speaker Daytona RSS390HF 4


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