Roberts S-911 Air Stream Speakers

 I came across a cool pair of Roberts S-911 Air Stream System speakers this week for a great price. There is little information on the internet on these speakers but a lot of information on the equivalent Akai SW-30 speakers. When you Google these the only pair that come up is a pair that was for sale on Canuck Audio Mart.

These look really cheap but they are a brilliant back horn loaded design or labyrinth designed speakers with a Foster FE-103 or equivalent hi sensitivity 4" full range driver.

   

 

 

When I opened these speakers up they had a 4" Roberts clone of the Foster FE-103 speaker inside the box. They look like they have a inexpensive cabinet which they kinda do, but there in not a lot resonance from a 4 inch driver to colour the sound with the cabinets.

There is a current day following of Foster FE-104 speakers that used a Horn Loaded design to produce sufficient bass, not window shaking bass but bass you can hear down to about 50Hz.

 

 The original Akai Sw-30 speakers are the exact same as the Roberts which tells me they are from the same factories in Japan.In fact searching for Roberts speakers comes up with plenty of models that look like Akai equivalent. 

 

 

The frequency response: 50 - 17'000 Hz and the efficiency: 95 dB / W / 0.5 m which would be about 92 dB at 1 meter. these are currently hooked up to a Fosi class D amp and would also sound great on a single ended tube amp.

Bass is surprisingly good in a close monitor space, midrange is also great and the highs might not be as crisp as a speaker with dome tweeters but it good to my ears. These speakers will fill a small room with great sound but would get lost in a big room.

I was really impressed with how efficient these are and how big the sound is in a small space.