I received a gift from a friend last week, a pair of vintage Akai Jet Road System SW-35 speaker. A quick search on www shows another type of SW-35 but it shows Jet Stream System printed on its front panel. It looks like the same but don’t know if any changes of internal structure and the driver unit.
I can’t find any further info about this driver. A Japanese page shows some simple specs as below:
1 way full range speaker
13cm driver made by FOSTEX
15 watts power handling
Freq. response 40Hz~18Khz
SPL 96dB @ 50cm
From info above, the driver must be a good driver if it was manufactured by FOSTEX. The SPL shows 96dB at 50cm, thats means 99dB at 1m? I don’t think this small driver can deliver such a high efficiency, it doesn’t show measurement taken at how many watts of power though.
The speakers external dimensions measured 170mm x 430mm x 270mm, all ply wood with veneer on it, and there’s a 50mm X 125mm of square opening at its lower back. I don’t know hows the internal port works , and see no screws at all on the speaker box. A youtube video shows those screws actually hidden under the faceplate veneer, I’m not going to open it since it works flawlessly. The back opening looks a little bit small for a back loaded horn , so I think this must be a transmission line design.
Search on used price records online and this pair are actually cheap , from less than 100USD to around 240USD, depends on its condition. This speaker using a 6.5mm mic jack as speaker terminal, very common in most of 70’s speakers.
Sound quality? I noticed some peak at its mid, and maybe I will build a notch filter to match it one day. Other than that, the spec shows lower frequency at 40Hz, but didn’t show how many -dB, the bass response sounds reasonable and in fact its a little boomy because of my room condition. may be I should test it in sound room for more accurate measurement.
Here’s a video of test video playing percussion music,
and here’s another video playing vocal track