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 Post subject: Re: The CUBE
PostPosted: 21 Sep 2020, 14:47 
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Joined: 03 Jun 2020, 11:06
Posts: 91
Location: France
Woodo wrote:
I like your analytical approach. I have a lot to learn about diy xovers. In the past I have purchased ready made ones, not really understanding the calculations. I should try harder.

It’s Interesting you used ferrite core inductors. For my BSC I used air cored but also bought a pair of ferrite core. In the end the air core fitted the small space better as I originally figured I wouldn’t use a BSC. Next time I will make some space under the box. Do you find the ferrite core sounds better?


Hi Woodo,

I'm waiting for the parts, so I can't tell...

For me, what makes the real difference is the DCR of the coil itself, not really the fact that it is Ferrite, Metal or Air core. Lower DCR - as found on Ferrite and Metal core coils - provides better efficiency and more dynamics mostly if the coil is serial, and it is quite easily heardable...

Insertion loss due to the DCR of a coil can be calculated by :

L = 20.log(Rm/(Rs+Rm))

Where :
L = insertion loss in dB.
Rm = impedance of the speaker in Ohms.
Rs = DCR of the coil in Ohms.

Examples for a speaker impedance Rm=8R :
If Rs=0.2R then L=-0.21dB. Well, OK.
If Rs=1R then L=-1.02dB. Here, this is not negligible anymore...

Another advantage of Ferrite or Metal core coils is that they neatly save the space taken in the enclosure volume for a lower DCR than Air coils, especially since it is a small volume enclosure (i.e. The Cube). 8-)

I know that some people will argue and say that Ferrite or Metal core are not as linear as Air core, and may saturate and distort. This is true for very high powers, largely over 100W RMS (metal core are often designed for 500W operation) but at the power we use our speakers most of the time, the benefits of the low DCR and space saving are much more obvious and interesting.

But it's me, OK ? ;)

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 27 Sep 2020, 16:19 
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Joined: 03 Jun 2020, 11:06
Posts: 91
Location: France
The CUBE Story comes to its end...

Oiling with Syntilor water-solvent incolor protective oil for kitchen furniture :

Image

Wiring the elements and stuffing :

Image

Image

First pictures finished :

Image

Image

Next step : measurements...

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 21 Oct 2020, 17:41 
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Joined: 28 May 2008, 21:53
Posts: 4591
Location: Winnipeg, CANADA
Great job on the enclosures. They look real good.

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 Post subject: Re: The CUBE
PostPosted: 25 Oct 2020, 08:49 
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Thanks @Gio ! :)

Image

Cheers,

-tbln.

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