X12 under construction

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   Hi peepz,

I recently started building the X12 design from Rog.  Instead of
the Selenium horn and P Audio adaptor I'm using an 1.4" Beyma horn
(TD565) with 60�x40� beamwidth.

I'm left with a couple questions though:

* because the horn is slightly bigger than the HL14-50 I was thinking
of increasing the height of the cab by 10 cm.  Can I get away with
this?

* Because the Beyma horn has a wider beamwidth than the HL14-50 do I have to alter the angle of the cabs to prevent lobbing?

* Does the cab need wadding?

* The SD740N I ordered has an impedanz of 8 ohms. 2 SN12MB in parallel
is 4 ohms.  Is the VX3 from Pro Audioparts suitable or do I need
to design my own crossover?  Or better using an active crossover
for the X12?

regards,

Jochen

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Jogge Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 09 August 2004 Location: Belgium Status: Offline Points: 63	Post Options Post Reply Quote Jogge Report Post Thanks(0) Quote Reply Topic: X12 under construction Posted: 07 October 2004 at 9:54am
	Hi peepz, I recently started building the X12 design from Rog. Instead of the Selenium horn and P Audio adaptor I'm using an 1.4" Beyma horn (TD565) with 60�x40� beamwidth. I'm left with a couple questions though: * because the horn is slightly bigger than the HL14-50 I was thinking of increasing the height of the cab by 10 cm. Can I get away with this? * Because the Beyma horn has a wider beamwidth than the HL14-50 do I have to alter the angle of the cabs to prevent lobbing? * Does the cab need wadding? * The SD740N I ordered has an impedanz of 8 ohms. 2 SN12MB in parallel is 4 ohms. Is the VX3 from Pro Audioparts suitable or do I need to design my own crossover? Or better using an active crossover for the X12? regards, Jochen
	Always listen to experts. They'll tell you what can't be done and why. Then do it.

Timber_MG Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 27 March 2004 Location: South Africa Status: Offline Points: 1454	Post Options Post Reply Quote Timber_MG Report Post Thanks(0) Quote Reply Posted: 07 October 2004 at 10:20am
	Passive crossovers are designed to work well with specific drivers in well-known cabs. Using a different horn would change the frequency/phase and polar response of the cab and it's quite possible that the design might work , but not to the extent of an optimal design (synergism is the word). The Selenium horn used is not of the constant directivity type, where as I think that that Beyma is (I speak under correction), hence if you are bent on using the cab, an active crossover might be a much safer bet, as CD horns need rising response to correct for the compression driver's falling power response. Generally one makes the angles of the side of the cab to equal a quater (1/4) of the coverage angle of the horn. Hope this helps Martin

Timber_MG Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 27 March 2004 Location: South Africa Status: Offline Points: 1454	Post Options Post Reply Quote Timber_MG Report Post Thanks(0) Quote Reply Posted: 07 October 2004 at 10:33am
	Heya Another thing is that IIRC the P.Audio driver has a 1.5" exit. It might thus be wize to use a horn with a 1.5" entry, as the mismatch could cause ripple in the HF response. Martin

RayVaughn Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 20 August 2004 Status: Offline Points: 62	Post Options Post Reply Quote RayVaughn Report Post Thanks(0) Quote Reply Posted: 07 October 2004 at 11:51am
	If you've got the budget to use an active crossover and another amp there are a lot of benefits in terms of control and protection. With a digi x-over you can time align the horn, apply eq and per band limiting - all good news.
	--------------- Ray Vaughn and on www.innerfield.co.uk www.rocketfestival.com

jerre Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 16 April 2004 Location: Belgium Status: Offline Points: 8	Post Options Post Reply Quote jerre Report Post Thanks(0) Quote Reply Posted: 22 February 2005 at 2:09pm
	hello, what is a good horn instead of the selenium one, this because the selenium horn is to hard to get for me. It's the intention to use 2 x12's /side, active crossed is no prob and I can choose between p.audio & beyma horns. I was thinking like above a td565 or maybe I should go for another driver?!? second question, how would the 122nd or mi100 driver from beyma fit in the x12? Edited by jerre