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Multi-Way Conventional loudspeakers with crossovers

B&W 602 goes under the knife (pics and measurements)
B&W 602 goes under the knife (pics and measurements)
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Old 5th July 2011, 08:55 AM   #41
fastelectrics is offline fastelectrics
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Join Date: Jul 2011
The graphs are excellent - at least they are very consistent with Joe D'Appiltios graphs on the same speakers (S2) .http://www.audioxpress.com/reviews/media/AX201DA.pdf. Given his qualifications andreputation not to mention the excellence of his designs (http://www.audioxcel.com/audioXpress...r%20Review.pdf)

It is likely his test results were done of very good equipment. As you are testing the same speaker his results are a great reference point for the accuracy of your test setup. Not often you get that for nothing!

I have a pair of these. I have been looking to solve a couple of problems with the sound

Tap the top of the box it rings!

For Crossover B&W specify 4th order at 4khz - as you say it 2nd at best, and at 3.5khz. There is a big problem arising from the above roll of characteritic of kevlar drivers

Above the X-over point the woofer has a hamp in its response. This hump is out of phase withthe tweeter and causes the notch a6khz. The notch isnt important BUT that lump causes a harsh colouration in the 602's - apparently this lump of breakup nodes is a characteristic of Kevlar and CF cones - in mine I think it may be why the tweeters seem prone to failure

And JoeD'Appilito says there is a ringing in the tweeter

so a new cross over and a couple of braces and better damping and something on that tweeter face palte should be ticketboo.
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Old 5th July 2011, 09:17 AM   #42
fastelectrics is offline fastelectrics
diyAudio Member
Join Date: Jul 2011
Tresch great thread for me I have a pair of thsoe speakers

BTW http://www.audioxpress.com/reviews/media/AX201DA.pdf
mentioned earlier is by Joe D'Appilito who is head of Snell and has designed a lot of phenomenal speakers eg http://www.audioxcel.com/audioXpress...r%20Review.pdf

Given D'Appilito's quals experience etc - his test gives you a reference standard for your measurement setup that most people would kill to have. In any event it looks like you have nailed it. CONGRATULATIONS!!

IMO the 602 seem like good drivers with skimypy execution. The cabinets ring - tap the top; the tweester rings, that the driver is Kevlar means it has that great lump of breakup frequencies above the X-over (3.5kz) which are not rolled off hard enough by the cheap X-over.

I have read several reviews which talk about the tweeter being the problem - the spectral decay D'Appilito did show it is a good unit, but the woofer dumps garbage into its freq range - so a better crossober which keeps the drivers 'in phase' is my first port of call I think. I think 3.5Kz is fine its out of the range the ear is sensitive to.

Bracing the box will help too and better damping material and some attention to the ringing in the tweeters front plate.

Be interesting to see how it shapes up as a i have a second set witha subwoofer in a HT setup - if it works I'll save a bomb - thanks for the great thread.
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Old 25th October 2012, 12:59 AM   #43
endersothergame is offline endersothergame  Canada
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Join Date: Oct 2012
I know this is an old post and I am a new comer however I am starting a new project involving replicating the cabinets for the DM 602's and I wonder if anyone here has exact internal measurements including port length and such?
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