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[Craig Leerman]

Can anybody tell me the real name of the following cabinet.  Some manufacturers call them "Horn Loaded", one calls it a "Clamshell Configuration" and another calls it a "Custom Ported" cabinet.




Also, what advantages besides a smaller width, does this design have over a front loaded/ported cabinet?  Would this design be any more directional than a front loaded?

And last, does anybody know of a website that shows all the possible sub designs (home stereo or not).  I am compiling a list for a class I teach and don't want to leave any designs out, no matter how esoteric or limited in use they are.

Craig

[David]

I don't know what that style is called, but it's supposed to be a more refined version of a direct-radiatiing woofer.  The idea is that the sound image is less distorted and has a stronger sweet spot.

Rey Audio of Japan uses such a design in their studio monitors, as does George Augspurger in his.

http://www.reyaudio.com/

[Mark Seaton]

Hi Craig,

I'll try and dig up a DIY speakerbuilding link that should cover what you need.  The sub designed mentioned would best be described as a "manifold" design.  While I've heard some pretty amusing claims, the primary advantage is that they kept the cabinet dimensions small enough to allow clusters to not beam horridly.  It is really just a matter of density; ie subs per pack dimensions.  A pair of 18" subs with the equivalent porting often makes for a rather large cabinet which can create directivity issues if you need to pack together more than 2-4 cabinets.  Of course if you are ground stacking that may dictate you need a minimum quantity to create a high enough and large enough base.

[Craig Leerman]

Thanks Mark!

I always thought manifold subs had the drivers directly facing each other like a EV MTL cab and not splayed at an angle like this type of design.  I guess I'll call this one  an "Angled Driver Manifold Design cab!  

Craig

[Mark Seaton]

Craig Leerman wrote on Wed, 13 October 2004 18:13

Thanks Mark! I always thought manifold subs had the drivers directly facing each other like a EV MTL cab and not splayed at an angle like this type of design.  I guess I'll call this one  an "Angled Driver Manifold Design cab!   Craig

If there is one seriously important factor to impress upon a class regarding bass reproduction, that would be the concept of wavelength and significant acoustic dimensions.  We get past many matters of confusion if this is understood.

Go with an average of 1130 ft./sec. and you are close enough for the purpose.  Now point out that in general, any distance less than 1/4 wavelength is insignificant to that frequency.  At 100Hz, this would be 1130'/100Hz = 11.3' (11'-3.6") for one wavelength.  Divide by 4 for 1/4 wavelength and you find that a total distance of anything less than 2.825' or ~2'-10" is mostly insignificant at 100Hz.  Since the wavelength continues to get longer with lower frequencies, this distance is insignificant to all frequencies below 100Hz.

Now cover the matter of scaling, where 2x that distance, or about 5'-8" won't have much effect below 50Hz.  On the flip side of that, you find that at 1/2 wavelength, or ~5'8" at 100Hz is where you see a cancellation in this dimension.  Think about it...  If two drivers are 1/2 wavelength apart, and you are standing just outside one speaker, looking at the other, the other will arrive 1/2 cycle late, which is equal to 180 degrees, and so they cancel to a large degree(one is late, so they don't cancel perfectly).

[Alan Searchwell]

Craig,

Replying to a post on this board had me scavenging info from all over . Here's some stuff I pulled together. This guy has some neat illustrations to go with his narrative

http://yu-ra.tripod.com/horn.htm

This website covers five basic sub-woofer types

http://www.diysubwoofers.org/

Here's a link someone posted a while back to a page with a wide selection of links (many dead) to bass horn designs.

http://www.mcsoundlight.com/horn.htm

Don't know if there's anything there that will be new to you or the answer to what you would call the box in the picture. Heck, even this page on the EAW website just calls it a "vented enclosure"

http://www.eaw.com/products/SB1000zRi.html

Hope you find something useful in here!

[Steve Shafer]

http://www.tcsaudio.com/products/tcs2800.html

Although the drivers cover the low mids, the Yorkville TX-8 has a similar design.

Steve S

[Too Tall (Curtis H. List)]

David wrote on Wed, 13 October 2004 09:17

I don't know what that style is called, but it's supposed to be a more refined version of a direct-radiatiing woofer.  The idea is that the sound image is less distorted and has a stronger sweet spot. Rey Audio of Japan uses such a design in their studio monitors, as does George Augspurger in his. http://www.reyaudio.com/

For this to make any difference we are talking up into the mid frequencies. I looked at the site (couldn't read it) and my guess is the crossed fired woofers in the picture go up well into the high mids.
   OTOH the box sited is purely a sub woofer. The fact that they are angled will not effect the sweet spot since there is nothing coming out of the box above 100Hz (typically).

For what they do in sub frequencies see Mark Seaton's explanation.
Too Tall