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 Post subject: The CUBE
PostPosted: 29 Aug 2020, 16:28 
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Joined: 03 Jun 2020, 11:06
Posts: 91
Location: France
Not a subwoofer, but a pair of bookshelf loudspeaker enclosures... :)

OK - I'll pass quickly on construction details - just enough for understanding :

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Made from 18mm thick glulam Beech wood, cubical shape (hence the name) at 200x200x200mm, fully stuffed laminar decompression principle, 2-ways with 4" Woofer ( Eltax S-106 or Monacor SP-100/8) and 1/2" Tweeter (Audax TW51A).

Next step : radiusing the edges at R=12mm all around with a router. 8-)

And... Waxed finish? Oiled ? Tinted ? :confused: :confused: :confused:

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 30 Aug 2020, 08:17 
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Location: France
Radiused :

Image

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 06 Sep 2020, 15:04 
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Posts: 91
Location: France
Break-in of the speakers :

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These ELTAX S106 woofer hed a Fs at 88 and 92Hz as is, decreased to 80 and 81Hz once broken-in.

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I'm waiting for a pair of Monacor SP-100/8 that should show a Fs at 60Hz.

So Wait and See... ;)

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 07 Sep 2020, 00:14 
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Joined: 13 Jan 2018, 21:33
Posts: 359
Location: australia
Very nice! Trust they sound good.

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 Post subject: Re: The CUBE
PostPosted: 07 Sep 2020, 14:09 
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Joined: 03 Jun 2020, 11:06
Posts: 91
Location: France
Thanks Woodo ! ;)

According to the simulations, I can expect a F3 at 70-75Hz with the Monacor SP-100/8. The Eltax is nicer looking, but has a measured Fs at 80Hz instead of 60Hz spec'ed for the Monacor :

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I'm waiting for the Monacor to be delivered, in order to see if I can arrange an universal mounting drilling for both. I'll measure their respective T/S parameters and redo simulations...

For the moment, I'm working on my 3-way enclosure.

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 13 Sep 2020, 15:38 
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Work is on progress... :geek:

Cabs drilled :

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Speaker choice - I choose the Monacor, not the nicest, but probably with better performances :

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Stuffing material and placement :

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Crossovers - testing 2 options :

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Ready for listening and measurement :

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Wait and See... ;)

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 15 Sep 2020, 12:51 
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Location: France
First listening tests & comparisons in my small and messy listening room...

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The 1st Order 4KHz Butterworth X-Over behaves quite differently compared to the 2nd Order 4KHz Linkwitz-Riley X-Over plus Zobel network... I'm instant A/B-ing them in mono : one speaker with the 1st BTW, the other with the 2nd L-R.

No definitive conclusion for the moment :confused: :confused: :confused:

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 19 Sep 2020, 07:39 
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Joined: 03 Jun 2020, 11:06
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I'm experimenting / listening new X-overs :

Image

Wait and See...

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 20 Sep 2020, 12:46 
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Location: France
After several listening tests in 6 and 12dB/oct, Butterworth/Bessel/Linkwitz-Riley/Chebyschev designs, with and without Zobel networks, Fc at 4000 and 4500Hz, the most satisfactory design listened is this one :

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Which is a Linkwitz-Riley design tuned to 4500Hz. It offers a nice tonal balance, low directivity and intermodulation distortion (at high level).

The other showed a more or less forward midrange register, very lively at first listen but quickly tiring and ultimately unrealistic. The 6db/oct. configurations showed directivity lobes and "dirtyness" at high volume due to IMD. Also, Fc=4000Hz proved too low (for a tweeter resonance at 2900Hz), accentuating midrange register much more than 4500Hz.

I keep all the version of X-overs in order to do some measurements, in order to see if it correlates (or not) the listenings...

-tbln.

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 Post subject: Re: The CUBE
PostPosted: 20 Sep 2020, 17:30 
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Joined: 13 Jan 2018, 21:33
Posts: 359
Location: australia
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?

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