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

Showing 8 responses by gregm

Wow, Fiddler. I expect you're trying out Phy's recommended open baffle with the piano hinges on the side flaps... Planning to use a tweet???
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!
I can take the big Lexan baffles out of our coat closet, lean them against the smaller, wooden Koa baffle/driver, slipping the hole in the big baffles over the Lexan donut & driver for a really nice fit
Good waf idea! Tried something similar with a friend (using plexi for the "normal" baffle). The problem was securing together the two baffles, if you will, without transmitting too many vibrations from the driver baffle to the outer baffle. The compromise was to use 3 screws, two bottom one on top with a very thin layer of damping matl around the connection points. Of course, the "outer" baffle was calculated to be flush with the driver... Cheers
You might test it out using clamps... we actually drilled the appropriate holes on both baffles
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!
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
Golix: differences basically as above, in my 1st answer to your post.
It dawns on me (belatedly) that what you read in the handbook probably refers to the fact that the closed box is an approximation of an IB -- since it's quite impractical to install drivers on the front wall of our house, the back wave radiating into the street beyond:)

Some differences, as above, the IB completely separates front & back waves; the box does not (because the enclosure radiates sound). The IB (take a wall of yr house, for example) is larger (i.e. infinite) than the longest wave-length radiated by the driver...
Of course the resulting ectromechanical system parametres of the two systems are completely different too. Cheers!