Bang & Olufsen Beolab 6000

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Dear Friends. I have been a member of DiyAudio for some years, but I have usually intervened in an analogical source.
Today I turn to the loudspeaker sector.
The issue is that I bought in confiscation of customs, repair kits Beolab 6000 (U $ S 10 the 4 speakers!)
I know they are active speakers, with a rare design, of aluminum with 10 cms of height and 10 cms approximately of diameter, bass reflex.
I ask how I can make two cabinets for use with an internal digital amplifier TPA3118 PBTL Mono Digital Amplifier Board 1X60W 8-24V POWER AMP Replace TPA3110 | eBay, to amplify TV audio.
I would like to take advantage of them since, from what I have seen on the web, their cost per unit is around US $ 100-140.
Greetings and thanks.
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So you are asking how to design a complete loudspeaker around those woofers. That is not a trivial task.


For a proper design, you would need frequency response and impedance measurements of the woofers and its Thiele & Small parameters. These woofers are not sold separately so these data are not available, you will have to measure them yourself.


If you just want to build something and the result does not have to be that good, here is what you can do. Put each woofers in a closed box and add a 1" dome tweeter. Run the woofer full range, cross the tweeter with a capacitor of a few µF and attenuate it with a resistor of a few ohms. What values work can be found by experimenting.
 
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From what I read on the web, the internal volume is only 3 liters ???, with bass reflex.
If I make an internal 3-liter MDF cabinet, a reflex tube will not be calculated to be tuned to at least 60 Hz-80 Hz.
The woofers have 16 ohms (they go in parallel that is 8 ohms) and 9 cm in diameter their membrane.
 
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Thank you. Very interesting video.
It occurred to me to make the cabinet with a PVC tube 110 cm high and 10 cm in diameter, cut in half lengthwise, placing a MDF board on the front. The design similar to the original speaker.
I do not know if the pvc on the back is adequate
 
I bought . . . repair kits Beolab 6000 . . . I know they are active speakers, with a rare design, of aluminum with 10 cms of height and 10 cms approximately of diameter, bass reflex.
The correct dimensions of the BeoLab 6000 speakers are 20 x 110 x 22cm (W x H x D) with a net volume of 3 litres. The woofers are 9cm. Adaptive bass equalistion (ABL) is used in a bass reflex cabinet. Effective frequency range 55Hz to 20,000Hz. Hope this information will be of assistance.

P.S. I note you have quoted the correct height in your latest post! :)

P.P.S. The circular form of a pvc back would make for a rigid shape, so you might be onto something there. You'd need a larger pipe diameter than 10cm to realise the 3 litres of volume though.
 
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So if B & O uses an amplifier with a bass boost, I'll have to use small 3-liter boxes and add a subwoofer.
Is it convenient to use the closed box to avoid calculating the bass reflex?
Without the adaptive bass equalisation used by B&O, you are correct in thinking that these 9cm units might only be useful as midrange drivers. For that reason, I would start by experimenting with a sealed midrange cabinet for the 9cm drivers. It's all a bit of a hit or a miss, so I would do some experimentation using a regular box before going to the time and expense of making your 'cylindrical' enclosures and separate woofers. Keep things in perspective!
 
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I'd try some cardboard boxes first, all the way up to a dozen liters.


Somewhere between boomy and thin(box on floor to test,
cuts the baffle loss in half and it's easier to guess what a solid(and not leaky) box would be like.


If you make a solid baffle, you can mock up a pretty good cylinder with cardboard.
If you like it you've got a template for thin ply or whatever you are using for the curved surface.
 
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