Leather-wrapped carpet speaker 1 short

Leather speaker short version

"Sylinx" prototype No. 5 "leather-wrapped carpet speaker" has been completed.

  • Speaker unit ALPAIRE7 v3 (ported from prototype No. 1)
  • Cylinder length 300mm
  • Cylinder diameter φ = 138mm
  • Enclosure cow leather t = 4.0mm
  • Base stainless vibration t = 3.0mm

[Speaker unit]

ALPAIR7 does not produce bass at first, but as aging progresses, it becomes more prominent.This time, I replaced it with a unit that had been aged for about half a year.If you don't have enough bass, put it in the corner of the room and it will improve a lot.

[Cylinder length]

The height is 30 cm to prevent it from tipping over.It is a measure for children.
Bass is good enough at this length thanks to the stainless steel base at the bottom and the aged ALPAIR 7.

[Cylinder diameter]

This time, we did not install a baffle plate and wrapped thick leather around a unit with a diameter of 13 cm.This is to eliminate the incidental sound caused by the baffle plate and bring it closer to the point sound source.


Uses 4mm genuine cow leather.In order to fix the speaker unit, I made thick leather with no elasticity.The cross section is also beautiful because it is a cored leather that is dyed to the inside.

Regarding the material of the soft enclosure, from my experience so far, I have found that the following three points are important.

  • Sound absorption: It weakens the air column resonance and leaves the bass while attenuating the mid-high range.
  • Sound insulation: Light and thin materials tend to leak sound from the side.It is better to have airtightness and a large internal loss.
  • Resonance: The enclosure is greatly affected by slight reverberation.It does not resonate as much as soft materials.If it is hard, it will easily resonate and resonate with the air column.

However, a soft material that absorbs sound well tends to leak sound, and a material that is highly airtight and has good sound insulation is hard and easily resonates with the air column.

In that respect, carpet is an ideal material that satisfies all of sound absorption, sound insulation, and resonance.The internal loss is very large due to the presence of hair.It also has sound insulation, and the sound becomes firmer by increasing the number of turns.

The genuine leather used this time is a material that has a large internal loss due to the condensed fibers that are inextricably entwined in all directions.It is highly airtight and has a moderate weight.It does not absorb much sound, so it is not suitable for enclosures by itself, but when combined with a material with high sound absorption, it may become an ideal soft enclosure.

Genuine leather wrap


The base is a 3mm thick stainless steel vibration disk.The space under the bass is an important part of reducing mid-high tones and balancing bass.This time, the gap is about 6 mm.
If you make it a closed type without providing a gap, the sound will be a little trapped.If the air is removed from the bottom, the sound will be smooth and clear like a carpet speaker.
However, if the gap is large, mid-high range sounds are likely to leak, so it is better to narrow it to some extent.
The size of the disc also affects the bass.

Stainless steel base


I had a hard time selecting a sound absorbing material to be combined with leather.Ordinary rugs aren't enough, and as a result, soft shaggy rugs made of microfiber are best, with a clear sound that forgets the shortness of 30 cm.
This time, we focused not only on the sound, but also on the rational structure, texture and design.