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Multi-Way Conventional loudspeakers with crossovers

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Old 18th November 2016, 09:06 PM   #11
Charles Darwin is offline Charles Darwin  United Kingdom
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The main problem of taking an 8" up to 2.6k is usually beaming but I suppose the horn thing helps dispersion because looking at Beyma's pdf it looks pretty good and continuous.

However their distortion graph (bless Beyma for having the decency to publish any!) for the tweeer part shows a peak between 1.6 and 2.5kHz. The higher xover frequency with a steeper slope should help with that.
Also it seems that you need to pad the tweeter down by 8 or 10dB.



I have not heard or worked with the driver but going by the published data I think the FD2CX would be much more suitable than the one you bought.
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Old 18th November 2016, 09:37 PM   #12
Zoran is offline Zoran  Serbia
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If You have idea to listen to these speakers that close sitting with the computer, that is very good way to get outside in the open space. Don't get me wrong please, but You will stand short time in-front. The beaming and decibels will fried you out sweet spot. lowering the levels would not help
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Old 18th November 2016, 10:31 PM   #13
Drummer 35 is offline Drummer 35  Spain
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Charles, your explanation is very helpful. Will return the xover and will order the proper one.

Zoran, maybe you are right and this is not the best setup for nearfield. Anyway, Ill use them mostly as studio monitors for playing synths and rarely, listen some records.
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Old 18th November 2016, 11:02 PM   #14
Charles Darwin is offline Charles Darwin  United Kingdom
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Personally I think co-axial are excellent as nearfields.

I'm using 12" Tannoys myself! ;-)
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Old 19th November 2016, 07:20 PM   #15
academia50 is offline academia50  Argentina
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Quote:
Originally Posted by Charles Darwin View Post
Definitely use foam on the inside of the cab.
I think the felt behaves better

How to Use Sound-Damping and Acoustic Materials in DIY Loudspeakers


Quote:
Originally Posted by Charles Darwin View Post

Everywhere except the baffle and probably double behind the driver.


" ...............a sound absorbing material, such as fiberglass should be glued or stapled so that it covers the inside of the enclosure.

baffle will inset in front. Glued and screw in place. "
( See attached photo )



Infinity SM 62 bookshelf DIY upgrade

( see post 28 )


I would like someone to explain to me technically because no absorbent material should be placed in the baffle itself. Many years ago I followed JBL's instructions to the letter, did I misunderstand? Should I remove the fiberglass from the front panel? Why ?
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Old 19th November 2016, 07:23 PM   #16
academia50 is offline academia50  Argentina
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Quote:
Originally Posted by Charles Darwin View Post
Personally I think co-axial are excellent as nearfields.

I'm using 12" Tannoys myself! ;-)
I agree, and far field too, I can move quite off the axis and the sound does not change too much.
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Old 19th November 2016, 07:49 PM   #17
Trollet is offline Trollet  Sweden
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Help 8" coax project.
I've used 8G40 drivers in downtuned BR's, just as Beyma says in the PDF.
The thing is that these drivers can take one h*ll of power.
They just need a lot of eq...

I have also tested 2x 8G40 and a cp380 driver i backloaded horn tuned to 45hz.
500w was no problem without low cut filter !

Your drivers work well in many diffrent boxes, but will need a lot of eq to play down to about 45hz. I have listened to them in BLH and BR. As Zoran say's they need some space to the listener to work well, then you will have a very detailed and clear sound.

Regards

Figge
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Old 19th November 2016, 07:49 PM   #18
augerpro is offline augerpro  United States
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That article is simplistic, out-dated, and wrong. A little searching should turn up materials with broadband sound absorption, appropriate thickness, and proper placement techniques.
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Last edited by augerpro; 19th November 2016 at 07:51 PM.
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Old 19th November 2016, 09:08 PM   #19
academia50 is offline academia50  Argentina
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That article is simplistic, out-dated, and wrong. A little searching should turn up materials with broadband sound absorption, appropriate thickness, and proper placement techniques.
Perhaps they should specify where low frequencies begin and end ?

Close-up acoustic foam.

Generally available in two shapes / profiles, flat and egg box, the foam family are usually opaque in colour and have a closed cell construction, The foam cells are chosen to be a specific size / diameter in order to provide a bulk material characteristic suitable for acoustic damping, i.e. the cells are mostly airtight and provide resistance to the passage of air if you try to blow through the material. This closed cell structure absorbs energy when the cell content, air, is compressed and rarefied due to the sound pressure wave. This type of damping is used to alter the high frequency response of cabinets and transmission lines. It does not work well for low frequencies as the amount of damping / energy absorption which the foam can support is relatively small.

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Old 20th November 2016, 01:23 AM   #20
augerpro is offline augerpro  United States
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Originally Posted by academia50 View Post

Perhaps they should specify where low frequencies begin and end ?

Close-up acoustic foam.

Generally available in two shapes / profiles, flat and egg box, the foam family are usually opaque in colour and have a closed cell construction, The foam cells are chosen to be a specific size / diameter in order to provide a bulk material characteristic suitable for acoustic damping, i.e. the cells are mostly airtight and provide resistance to the passage of air if you try to blow through the material. This closed cell structure absorbs energy when the cell content, air, is compressed and rarefied due to the sound pressure wave. This type of damping is used to alter the high frequency response of cabinets and transmission lines. It does not work well for low frequencies as the amount of damping / energy absorption which the foam can support is relatively small.

I'm not following...
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