Hi everyone.
I recently dismantled a set of Technics SB-EH60 multi-way loudspeakers that I got from a car boot say for £3! The tweeter and midrange were the usual sealed enclosure, crappy quality units used on speakers sold with micro-systems but the woofer/mid-bass driver had me intrigued. The crossover point for the woofer to mid was around 1-2kHz but it was only a simple R/C x-over so it didn't have a very steep rolloff.
The driver is about 5-6ins in diameter (excluding metal mounting that the surround is attached to) and at a guess has a voicecoil diameter of around 1.5-2ins. When still in the (ported) box, the speakers were rated at 60W (DIN) and 160W (music) power so I'd assume that this driver is rated at around [email protected]
Then things start to get slightly unusual. The dust cap is made from metal, which I know is not a brand new concept but is strange to see it on such a cheap set of speakers. Also, the shape of the dust cap is not exactly conventional either, as it is stepped inwards and is glues to the voicecoil on the other side. My guess for the cap being metal is to act in a similar way as a whizzer on other speakers, to allow it to reproduce higher frequencies more accurately (it did have to go up to 1.5kHz though!). Also, on the underside of the cone, there is a small cutout in the cone, hidden from sight by the dust cap (pic 3). I'm assuming that this is some kind of cooling system, but again not conventional (vented voice coils often have a hole drilled through the magnet assembly instead).
When tested, the driver seems to be ok to around 30-40Hz, but when in free air, bottoms out very easily. I was thinking of using two of these drivers in sealed boxes (to provide some damping) as subwoofers in my main system, driven by a 60W amp (LM3886 probably). The main amp in this system is based on the LM1875 (2x 25W).
I just posted here for people's opinions and to see what they thought about this.
[IMGHTTPDEAD]http://files.diyaudio.com/forums/gallery/data/1597/medium/DSCF2186.JPG[/IMGHTTPDEAD]
[IMGHTTPDEAD]http://files.diyaudio.com/forums/gallery/data/1597/medium/DSCF2187.JPG[/IMGHTTPDEAD]
[IMGHTTPDEAD]http://files.diyaudio.com/forums/gallery/data/1597/medium/DSCF2188.JPG[/IMGHTTPDEAD]
I recently dismantled a set of Technics SB-EH60 multi-way loudspeakers that I got from a car boot say for £3! The tweeter and midrange were the usual sealed enclosure, crappy quality units used on speakers sold with micro-systems but the woofer/mid-bass driver had me intrigued. The crossover point for the woofer to mid was around 1-2kHz but it was only a simple R/C x-over so it didn't have a very steep rolloff.
The driver is about 5-6ins in diameter (excluding metal mounting that the surround is attached to) and at a guess has a voicecoil diameter of around 1.5-2ins. When still in the (ported) box, the speakers were rated at 60W (DIN) and 160W (music) power so I'd assume that this driver is rated at around [email protected]
Then things start to get slightly unusual. The dust cap is made from metal, which I know is not a brand new concept but is strange to see it on such a cheap set of speakers. Also, the shape of the dust cap is not exactly conventional either, as it is stepped inwards and is glues to the voicecoil on the other side. My guess for the cap being metal is to act in a similar way as a whizzer on other speakers, to allow it to reproduce higher frequencies more accurately (it did have to go up to 1.5kHz though!). Also, on the underside of the cone, there is a small cutout in the cone, hidden from sight by the dust cap (pic 3). I'm assuming that this is some kind of cooling system, but again not conventional (vented voice coils often have a hole drilled through the magnet assembly instead).
When tested, the driver seems to be ok to around 30-40Hz, but when in free air, bottoms out very easily. I was thinking of using two of these drivers in sealed boxes (to provide some damping) as subwoofers in my main system, driven by a 60W amp (LM3886 probably). The main amp in this system is based on the LM1875 (2x 25W).
I just posted here for people's opinions and to see what they thought about this.
[IMGHTTPDEAD]http://files.diyaudio.com/forums/gallery/data/1597/medium/DSCF2186.JPG[/IMGHTTPDEAD]
[IMGHTTPDEAD]http://files.diyaudio.com/forums/gallery/data/1597/medium/DSCF2187.JPG[/IMGHTTPDEAD]
[IMGHTTPDEAD]http://files.diyaudio.com/forums/gallery/data/1597/medium/DSCF2188.JPG[/IMGHTTPDEAD]
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