subwoofer design problem - Page 4

Super · 31st October 2001, 09:55 PM

When building a sub, as mentioned, the cubic/rectangular shape isnt of importance. Lack of resonance is the key. Rectangular/cubic shaped boxes are easier to brace and allot a greater amount of bracing than several other types of enclosures. Cylinders are also becoming popular, because the shapes is self supporting. When internal force is exerted, its exerted equally within the enclosure, making it extrememly rigid and with minimal resonances. However, some people may have problems with the entire enclosure moving around the floor (like the HSU subs) because of their relatively light weight. Spherical enclosures would also have their benefits, but they would be particularly large and difficult to couple to the floor.

pkgum · 1st November 2001, 07:06 AM

can someone tell me detailed web pages that can teach ppl about how to make subwoofer?

f4ier · 1st November 2001, 07:17 AM

If you don't want to spend money for the above-mentioned book by Vance Dickason, try a nearby engineering library or architecture library. They might have a copy of such great books.

Isaac

pkgum · 1st November 2001, 10:52 AM

thomas and issac,

I find Unibox with the box simulator thingy useful. Can only both of them make a good subwoofer?
the Loudspeaker Cookbook costs $75US in my country

Super · 1st November 2001, 01:15 PM

http://www.subwoofers.org and http://www.diysubwoofers.org are two very informative sites for the beginner. http://www.diysubwoofers.com also has numerous links to subwoofer projects, partaining to the various types of subwoofers, i.e bandpass, sealed, ported, etc.

ThomasW · 1st November 2001, 02:06 PM

Unibox is a very good and accurate program.

Where are you located?

$75 for 'The Cookbook' seems insane! The current edition is #6. Some suppliers have put older the 5th edition on sale just to clear out inventory.

baby_huey0 · 1st November 2001, 02:33 PM

The only place I could find to buy the cookbook in Nova Scotia was to order it from Solen. It cost about $63 cdn plus shipping and plus taxs(15%in NS). Thats about the same amount I would have to pay. I found it easily at my local library though.

pkgum · 1st November 2001, 09:07 PM

lm from Australia

thomas,

can you tell me the 'Le', the 'series resistance',
and 'the nominal power rating' of the BP1503 to
fill in the blank spaces in the Unibox? I cant find them in the DUMAX report

everyone,

What does UNIBOX mean by 'leakage'...enclosures are supposed to be airtight..aren't they?

And what the heck is alpha?

[Edited by pkgum on 11-01-2001 at 03:36 PM]

f4ier · 2nd November 2001, 12:22 AM

I'm from Australia as well

All loudspeaker-related material (except for Acoustical Society of America journals... last I checked) is now located at the Univ. of Sydney's architecture library since Audio Eng. is taught there. I remember back in '98 seeing non-Univ. of Syd. students being able to borrow books... or maybe my eyes were deceiving me 'cause of multiple exams and assignments at the time

The LDC by V. Dickason is only AU$40 (around US$20) at http://www.jaycar.com.au For less than AU$20 (10 cents/page last I checked), you could photocopy the whole book and put it on plastic binders.

Quote:

I find UNIBOX with the combined box simulator thingy very useful. Can only both of them create a accurate and good sounding subwoofer?

UNIBOX is a more finalised program and I even think it has already been coded for large signal analysis (as well as small-signal analysis). My box simulator? If so, it is still in its infancy due to school work etc. Large signal analysis, better interface and more features soon. Try lspCAD, which is a powerful simulator, if you haven't already downloaded it.

Quote:

What does UNIBOX mean by 'leakage'...enclosures are supposed to be airtight..aren't they?

Even with an airtight enclosure, the driver itself, the port(s), passive radiator(s), speaker terminal(s) etc. can introduce leaks, which lower system performance. Typical values are 5, 7 and 15 -- higher figure being less 'leaky.'

Quote:

And what the heck is alpha?

Alpha is usually the driver volume, Vas, to enclosure volume, Vab, ratio.

Isaac

[Edited by f4ier on 11-01-2001 at 06:25 PM]

ThomasW · 2nd November 2001, 02:22 AM

Hi

The Le isn't needed for subwoofer designs where there is an active XO. But since I'm such a nice guy I measured one of my 1503s and the inductance is 4.28mh

The power handling is in excess of 1Kw, so for your model just use 1000 watts

31st October 2001, 09:55 PM	#31
Super diyAudio Member Join Date: May 2001 Location: Connecticut	When building a sub, as mentioned, the cubic/rectangular shape isnt of importance. Lack of resonance is the key. Rectangular/cubic shaped boxes are easier to brace and allot a greater amount of bracing than several other types of enclosures. Cylinders are also becoming popular, because the shapes is self supporting. When internal force is exerted, its exerted equally within the enclosure, making it extrememly rigid and with minimal resonances. However, some people may have problems with the entire enclosure moving around the floor (like the HSU subs) because of their relatively light weight. Spherical enclosures would also have their benefits, but they would be particularly large and difficult to couple to the floor. __________________ Bryan

1st November 2001, 07:17 AM	#33
f4ier diyAudio Member Join Date: Sep 2001 Location: Sydney	If you don't want to spend money for the above-mentioned book by Vance Dickason, try a nearby engineering library or architecture library. They might have a copy of such great books. Isaac __________________ Crossover/Subwoofer Simulator

1st November 2001, 01:15 PM	#35
Super diyAudio Member Join Date: May 2001 Location: Connecticut	http://www.subwoofers.org and http://www.diysubwoofers.org are two very informative sites for the beginner. http://www.diysubwoofers.com also has numerous links to subwoofer projects, partaining to the various types of subwoofers, i.e bandpass, sealed, ported, etc. __________________ Bryan

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1st November 2001, 07:06 AM	#32
pkgum diyAudio Member Join Date: Oct 2001 Location: sydney	can someone tell me detailed web pages that can teach ppl about how to make subwoofer?

1st November 2001, 10:52 AM	#34
pkgum diyAudio Member Join Date: Oct 2001 Location: sydney	thomas and issac, I find Unibox with the box simulator thingy useful. Can only both of them make a good subwoofer? the Loudspeaker Cookbook costs $75US in my country

1st November 2001, 02:06 PM	#36
ThomasW diyAudio Member Join Date: Oct 2001 Location: 5280'	Unibox is a very good and accurate program. Where are you located? $75 for 'The Cookbook' seems insane! The current edition is #6. Some suppliers have put older the 5th edition on sale just to clear out inventory.

1st November 2001, 02:33 PM	#37
baby_huey0 diyAudio Member Join Date: May 2001 Location: Nova Scotia, Canada	The only place I could find to buy the cookbook in Nova Scotia was to order it from Solen. It cost about $63 cdn plus shipping and plus taxs(15%in NS). Thats about the same amount I would have to pay. I found it easily at my local library though.

1st November 2001, 09:07 PM	#38
pkgum diyAudio Member Join Date: Oct 2001 Location: sydney	lm from Australia thomas, can you tell me the 'Le', the 'series resistance', and 'the nominal power rating' of the BP1503 to fill in the blank spaces in the Unibox? I cant find them in the DUMAX report everyone, What does UNIBOX mean by 'leakage'...enclosures are supposed to be airtight..aren't they? And what the heck is alpha? [Edited by pkgum on 11-01-2001 at 03:36 PM]

2nd November 2001, 02:22 AM	#40
ThomasW diyAudio Member Join Date: Oct 2001 Location: 5280'	Hi The Le isn't needed for subwoofer designs where there is an active XO. But since I'm such a nice guy I measured one of my 1503s and the inductance is 4.28mh The power handling is in excess of 1Kw, so for your model just use 1000 watts

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