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Speaker design myths revealed

I found this at the Jordan web site. Maybe the experts can say whether this is true or not. I will say I have not heard the big improvement with a narrow baffle vs. wide baffle that I am "suopposed" to.
Q: In your VTL box design, why is the JX92S fitted in the wide face when it is common knowledge that the box should be as narrow as possible?

A: 'Common knowledge' and scientific fact are often very different. The narrow front face is a fashion concept supported by some very questionable marketing rational. The indisputable scientific fact is that the ideal mounting for a loudspeaker is an infinitely large flat baffle and this is the concept used for all loudspeaker analyses. A wide baffle always sounds better.

Q: What are the recommended advantages of positioning loudspeakers as close to the wall as possible?

A: This positioning secures, to some extent, the advantages described in the previous question. In addition it minimises the time delayed reflections from the rear wall which contribute to confused imaging.

Q: Will placing next to a wall ruin the stereo image?

A: We cannot see any reason why this would impair imaging. Possibly more than any other manufacturer, we have concerned ourselves with accurate and stable imaging and certainly would not promote a design that would impair this.
cdc
fiddler
581 posts
 
From the experience of numerous other people, the baffle does not have to be very large to be effective if you aren't concerned about low bass frequencies. 50-60HZ is about what one could expect with a small baffle (see link below) and the subs come in where the bass begins to roll-off determined by the in-room response of the baffle.

Here is a link with several pictures:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=19883&perpage=10&highlight=lexan&pagenumber=7

And another:

http://www.dietiker-humbel.ch/micromag.htm

There are many more pics and threads elsewhere online about OB, but this is an example of the type of OB I am experimenting with.

I know jack**** about all this, but I trust both my friends and their ears. They both currently have really high-end systems and have been through several other high-end systems. My friend said his OB PHYs wiped the floor with his previous $$K speakers and all who have heard his OB's have been very impressed.
johnk's avatar
johnk
1,976 posts
 
this info is mostly for jordans only or other OB drivers, OB drivers need much help to produce any kind of range.Other drivers wouldnt perform well in theses type of designs
gregm
3,409 posts
 
Johnk: "OB drivers" = open baffle drivers??? If so, disabuse yourself. There no such thing as an "open baffle driver" (although certain drive units' T/S parametres may indicate good performance on an open baffle...). Cheers

Fiddler: what Twl notes above about diametres is a (unfortunate maybe) necessity. The links you give refer to ("quasi quasars") actually show baffles that should be ~0,5m wide (~20,5"). Good luck, the Phy is a beautiful unit!
cdc OP
1,855 posts
 
Nzera, do you have a link for Nelson Pass' comparision of the Jordan driver? I can't find it at 6moons archive
twl
3,251 posts
 
Fiddler, basically the baffle size requirement is directly related to the bass "wraparound" cancellation that is inherent in open baffle speakers. If you use subwoofers with these systems, then the baffles can be much smaller, depending upon how high you want to cross-in the subs.

For example, if you want the OB mains to only go down to 128Hz, then the quarter-wave formula would show a baffle dimension of 2' square.
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