2nd Order Crossover & Phase…

dynoPort · 21st May 2007, 02:19 PM

Am I right in thinking that if you have a 2nd order crossover the tweeter needs to be ‘out of phase’ but if I can recess it back from the mid/bass driver then it wouldn’t need to be reversed wired? If the crossover point is 3000hz the is there a calculation as to the depth difference?

See also this thread:

Ribbon Tweeter advice please

richie00boy · 21st May 2007, 02:23 PM

No the reverse phase connection assumes perfect physical time alignment. So in fact if you have a step you may be better off with in phase connection. You are best trying both and see. I think Svante might have some software to help.

sreten · 21st May 2007, 02:44 PM

See this thread :

BAMTM Tweeter polarity

Related to this crossover :

http://www.zaphaudio.com/BAMTM.html

/sreten.

dynoPort · 13th June 2007, 09:34 AM

Update…

For this single project I shall not be spending on specialist computer software, microphone, new soundcard, etc. instead I shall be groping around in the dark, well, semi dark at least, using my ears and basic maths. I have a calculated crossover which I have tried on one (mono) speaker and nothing disastrous happened! I’ll now assemble its twin and see what stereo sounds like.

Crossing over @ around 3400hz Visaton tweeter @ 8ohm Volt mid/bass @ estimated 11ohm I have a roughly (!) Bessel crossover with tweeter 3.3uf cap .68mh ind. Bass/mid 2.2uf cap .82mh ind. With a suitable L pad.

Thoughts? And will the Visaton need ‘running in’ before worthwhile results are heard?

Addendum:
In mono it seemed better with tweeter in phase.

I have a few test Cds with test tones etc is there anything specific to listen to that will uncover flaws in the crossover?

jnb · 13th June 2007, 11:01 AM

If you are using a second order electrical crossover, it seems unlikely that your acoustic response is second order.

Jay_WJ · 13th June 2007, 05:01 PM

Try simulation. You'll get much better results than simply by relying on text-book formulas and listening.

1. http://www.rjbaudio.com/Audiofiles/FRDtools.html
2. http://www.rjbaudio.com/Audiofiles/SWtutorial.html
3. http://www.rjbaudio.com/Audiofiles/d...alculator.html

Good luck,

Jay

Dave Bullet · 13th June 2007, 10:42 PM

DynoPort,

Totally agree with Jay. Take the time to learn and use the above simulation tools. In addition - use a crossover modeler once you have simulated the response of your drivers and created minimum phase using the above tools - plugging in your intended crossover above.

The above won't cost you any money - just time. In fact it is very likely to produce a better sounding speaker with less crossover iterations (= less $ spent on crossover parts to get it right) than listening and tweaking by ear.

Cheers,
David.

dynoPort · 14th June 2007, 08:19 PM

I cannot open 'speakerworkshop' I get a 'cannot run 16-bit program, it or one of its components is missing' message on clicking setup after I unzip it?

dynoPort · 15th June 2007, 10:15 AM

Quote:

Originally posted by dynoPort
I cannot open 'speakerworkshop' I get a 'cannot run 16-bit program, it or one of its components is missing' message on clicking setup after I unzip it?

However, it does work on another computer!

21st May 2007, 02:19 PM	#1
dynoPort diyAudio Member Join Date: Oct 2004 Location: Cymru/Wales	2nd Order Crossover & Phase… Am I right in thinking that if you have a 2nd order crossover the tweeter needs to be ‘out of phase’ but if I can recess it back from the mid/bass driver then it wouldn’t need to be reversed wired? If the crossover point is 3000hz the is there a calculation as to the depth difference? See also this thread: Ribbon Tweeter advice please

21st May 2007, 02:23 PM	#2
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	No the reverse phase connection assumes perfect physical time alignment. So in fact if you have a step you may be better off with in phase connection. You are best trying both and see. I think Svante might have some software to help. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

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21st May 2007, 02:44 PM	#3
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	See this thread : BAMTM Tweeter polarity Related to this crossover : http://www.zaphaudio.com/BAMTM.html /sreten.

13th June 2007, 09:34 AM	#4
dynoPort diyAudio Member Join Date: Oct 2004 Location: Cymru/Wales	Update… For this single project I shall not be spending on specialist computer software, microphone, new soundcard, etc. instead I shall be groping around in the dark, well, semi dark at least, using my ears and basic maths. I have a calculated crossover which I have tried on one (mono) speaker and nothing disastrous happened! I’ll now assemble its twin and see what stereo sounds like. Crossing over @ around 3400hz Visaton tweeter @ 8ohm Volt mid/bass @ estimated 11ohm I have a roughly (!) Bessel crossover with tweeter 3.3uf cap .68mh ind. Bass/mid 2.2uf cap .82mh ind. With a suitable L pad. Thoughts? And will the Visaton need ‘running in’ before worthwhile results are heard? Addendum: In mono it seemed better with tweeter in phase. I have a few test Cds with test tones etc is there anything specific to listen to that will uncover flaws in the crossover?

13th June 2007, 11:01 AM	#5
jnb diyAudio Member Join Date: Dec 2006	If you are using a second order electrical crossover, it seems unlikely that your acoustic response is second order.

13th June 2007, 05:01 PM	#6
Jay_WJ diyAudio Member Join Date: Mar 2006 Location: Indiana	Try simulation. You'll get much better results than simply by relying on text-book formulas and listening. 1. http://www.rjbaudio.com/Audiofiles/FRDtools.html 2. http://www.rjbaudio.com/Audiofiles/SWtutorial.html 3. http://www.rjbaudio.com/Audiofiles/d...alculator.html Good luck, Jay

13th June 2007, 10:42 PM	#7
Dave Bullet diyAudio Member Join Date: Jan 2002 Location: Wellington, New Zealand	DynoPort, Totally agree with Jay. Take the time to learn and use the above simulation tools. In addition - use a crossover modeler once you have simulated the response of your drivers and created minimum phase using the above tools - plugging in your intended crossover above. The above won't cost you any money - just time. In fact it is very likely to produce a better sounding speaker with less crossover iterations (= less $ spent on crossover parts to get it right) than listening and tweaking by ear. Cheers, David.

14th June 2007, 08:19 PM	#8
dynoPort diyAudio Member Join Date: Oct 2004 Location: Cymru/Wales	I cannot open 'speakerworkshop' I get a 'cannot run 16-bit program, it or one of its components is missing' message on clicking setup after I unzip it?

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