leather carpet speaker 1 short

leather speaker short version

"syrinx" 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 genuine leather t=4.0mm
  • Base Stainless vibration t=3.0mm

[Speaker unit]

ALPAIR7 doesn't have low bass at first, but as it ages, it will come out. This time, I replaced it with a unit that has been aged for about half a year. If the bass is lacking, placing it in the corner of the room will improve it considerably.

[cylinder length]

I set the height to 30 cm so that it would not fall over. It's child protection.
Even with this length, the bass is good enough thanks to the stainless steel base on the bottom and the aged ALPAIR7.

[Cylinder diameter]

This time, I didn't install a baffle plate and just wrapped the thick leather around the unit with a diameter of 13 cm. This is to eliminate incidental sound from the baffle plate and bring it closer to a point sound source.


4mm cowhide leather is used. In order to fix the speaker unit, I used thick non-elastic leather. The cross section is also beautiful because it is leather with a core that is dyed to the inside.

Regarding the material of the soft enclosure, from my experience so far, I found the following three points to be important.

  • Sound absorption: weakens air column resonance, attenuates mid-to-high frequencies while leaving low-pitched sounds.
  • Sound insulation: Light and thin materials tend to leak sound from the sides. It should be airtight and have a large internal loss.
  • Resonance: Enclosures are greatly affected by slight reverberation. It does not resonate as much as soft materials. If it is hard, it becomes easy to resonate and resonate with the air column.

However, soft materials that absorb sound well tend to leak sound, while materials that are highly airtight and have good sound insulation are hard and prone to air column resonance.

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

The genuine leather used this time is a material with large internal loss due to the condensed fibers intertwined in every direction. It is airtight and has a moderate weight. It doesn't absorb much sound, so it's not suitable for an enclosure by itself, but if you combine it with a material that absorbs a lot of sound, it can be an ideal soft enclosure.

Genuine leather roll


The base uses a 3mm thick stainless steel vibration disc. The space under the bass is an important part of reducing mids and highs and balancing bass. This time, the gap is about 6mm.
If you make it a closed type without providing a gap, the sound will be a little muffled. If the air is removed from the bottom, the sound will be more relaxed and clear like a carpet speaker.
However, if the gap is large, mid-to-high frequencies tend to leak out, so it is better to make it narrower to some extent.
The size of the disc also affects the bass.

stainless steel base


We had a hard time choosing sound absorbing materials to be combined with leather. Ordinary rugs are not enough, and as a result, soft shaggy rugs made of microfiber work best, with a clear sound that makes you forget the short length of 30 cm.
This time, we focused not only on the sound, but also on the rational structure, texture and design.