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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
golx9210
1 posts
 
In an open baffle scenario the lowest frequency transmitted depends on the smallest(!) distance between driver edge and baffle edge, thats why they are usually circular!
The baffle needs to extent a quarter wavelength in every direction,ie. to achieve 32Hz cut off the baffle has to have a radius of 8feet8inch or a diameter of 17ft4inch.
Thats why they stopped being used sometime prior to WW2 and have been replaced by the infinite baffle otherwise known as the closed box design.
From the top of my head Fiddlers use of 30inch board should result in a bass roll off starting between 300 and 400 Hz.
gregm
3,409 posts
 
Ouch, golx!
infinite baffle otherwise known as the closed box design
IB, closed boxes, ported, OB etc are all different...
the lowest frequency transmitted depends on the smallest(!) distance between driver edge and baffle edge, thats why they are usually circular
??? Were they circular, there would NO smallest distance. A circular baffle has the worst response pattern and is rarely used. Maybe your eye caught a sphere somewhere? The response pattern is much better there. BTW the smallest diametre is a valid point -- if that's what you're referring to.

they stopped being used sometime prior to WW2
You have me baffled! Cheers!
golixe7df
55 posts
 
I give you the one about the circular baffle, was mostly to show the size problem with open baffles.
With regards to the infinite baffle let me quote the "Audio & HiFi Engineers handbook":
'Infinite Baffle
The rear wave is'smothered' by mounting the speaker at the front of a sealed box.'
Where,then, is the difference between IB and closed box?
Now I am baffled.
gregm
3,409 posts
 
Completely different system parametres... one is a relatively small box trying to absorb the back wave and operating partly in 2pi and 4pi, the other has complete separation of the front & back waves (as in the driver mounted in a wall) the separator being larger ("infinite")than the longest wavelength reproduced by the transducer (i.e. radiates 2pi always).
Cheers
golixe7df
55 posts
 
Ok everywhere I searched I can only find IB=sealed box,even in some white papers and the relevant formulae are identical. Also at least two manufacturers(Linn,Quested) refer to their closed box designs as IB's. Driver manufacturers too use the terms interchangebly.
So could you elucidate a bit more on the differences?
Thanks
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