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Multi-Way Conventional loudspeakers with crossovers

Tweaking B&W DM 602 s2
Tweaking B&W DM 602 s2
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Old 24th March 2005, 12:58 AM   #21
caenot is offline caenot  Brazil
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Default Old B&W 602

I just opened my 602 this weekend (not version 2), and I can say that I got quite disappointed... not MDF, but particle board, woofer not flush mounted. The CC6 Central Channel were even worse.
Bracing is ok, port is ok, but the construction is not that good (FR measurement in CC6 showed a huge dip in high-frequency - waiting for my full PRAXIS to double check it).

I will do some upgrades later this year on these 2. The drivers seem nice and I will try something different using Solen Caps and good quality coils and cables (maybe the ones that Madisound sells).

With some experience in box building, I don´t believe that the box volume should be changed. Bear in mind that reflex boxes require a good alignment (SBB4, QB3, etc) that match TS Parameters with box volume and port length/width. If I perform the measurements I will post it here. If you want to change to MDF, go ahead, but listen to possible new ressonances as MDF is different from Particle board.
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Old 24th March 2005, 02:05 PM   #22
Jim85IROC is offline Jim85IROC  United States
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A 4khz crossover with a 6.5" woofer. I can only imagine with the response looks like 30 degrees off axis. I suspect that if you're able to measure and design a new filter, replacing that tweeter with something that can cross at 2khz will provide notable improvements in sound thanks to a much more favorable power response.
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Old 25th March 2005, 10:34 PM   #23
caenot is offline caenot  Brazil
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Default why not wood

Real wood is not usually a good choice. Remeber, wood is a type of material that changes with weather, humidity, etc. Speakers should be free from any leaks and be well braced. If you use wood, you will have to create an inner chamber that is completetly sealed.
Regarding sonus faber and others, they do not use real wood in a single piece. They use is as other companies (that build planes and boats) by pressing an gluing several layers of very thin slices of wood (a very few mm thicks). Using heat, humidity and pressure, the wood can be bended and then glued.. very, very expensive and complex (that is part of the huge costs).

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Old 4th May 2006, 08:52 AM   #24
bzfcocon is offline bzfcocon  Romania
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Hi everybody,

I would like to reopen this thread - thought I won't open a new one for that. I have a pair of 602 S3 and recently looked inside, willing to do some tweaking with the crossover.

To my amazement, the filter is not the usual second order ! I attached a schematic - the inductances of the coils are measured.
- it looks like a first order (1 coil) on the woofer and a third (!) order on the tweeter.
- on the filter PCB, there is place for a Zobel on the woofer (R + C across woofer), but these have been ommited (on purpose ?)

Now, I know that it's rather impossible to tweak the filter without driver parameters. But what do you think, can I improve anything ?

Originally posted by Jim85IROC
A 4khz crossover with a 6.5" woofer. I can only imagine with the response looks like 30 degrees off axis.
This is supposed to be a B&W feature. The kevlar woofer is not stiff but flexible, so, as frequency increases, only the central part radiates, thus the off axis response should remain ok. A high crossover point should also have benefits: it's out of the human voice range, so voices should be more natural.
Attached Images
File Type: jpg bw602xover.jpg (20.8 KB, 267 views)
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Old 4th May 2006, 01:12 PM   #25
sreten is offline sreten  United Kingdom
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Location: Brighton UK

the simple answer for the 602 S3 is you can't improve the crossover.

The crossover is probably asymmetric 2nd order acoustic
on the bass unit with 3rd order acoustic on the tweeter.

Asymmetry can help in compensating for the tweeters
acoustic centre being forward of the bass unit centre.

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