Interessanter Link

[walwal]

Sehr interessanter Link, besonders zu LS und Weichendesign.

http://sound.westhost.com/articles.htm

"geschlossener Sub ist besser; Klare Aussagen zu Widerständen und Kondensatoren, uvm"

Englisch

[doctrin]

Die infos zu CB und BR stehen die bei dem Artikel zu Satellitensystemen?

MfG

[walwal]

5 - Soundwave Vs. Pressure Mode
One claim that is very popular is that you cannot reproduce bass in a small space. While this is certainly true of soundwave propagation, it is completely false if pressure mode is excited within the space. In most rooms, there is a transition point between soundwave propagation and pressure mode (sometimes referred to as 'Room Gain'). That low frequencies can be reproduced in small spaces is clearly shown by headphones and car subwoofer systems. Both of these rely on pressure mode, and the low frequency -3dB point is defined by 'leakage' because the space is not perfectly sealed. In a completely sealed environment, bass reproduction is attainable right down to DC - not that this is actually useful. Most subwoofers ultimately rely on pressure mode to obtain the lowest frequencies in typical rooms, and it is notable that vented systems in particular are unable to excite the pressure mode properly in many rooms.

One of the reasons for this could be that there is a vent that allows the pressure to equalise. In theory, this is meant to be a resonant system, where the back wave of the loudspeaker is inverted in phase and augments the main cone wavefront. That the principle works is demonstrated by many large systems in auditoria, theatres and even outdoor venues, but all of these are large spaces where soundwave propagation is dominant.

When room dimensions become small compared to wavelength, soundwave propagation will not work, and bass can only be reproduced by pressurising (and de-pressurising) the listening space ... pressure mode. In tests I have performed in my workshop, a vented subwoofer seemed to make a lot of noise, but completely failed to produce bass that could actually be felt. A similar driver in a sealed box causes the whole house to vibrate, something that I have not been able to achieve to the same (or even similar) levels using any vented subwoofer system.

To some extent, this section is comprised of musings on my part, and at this stage I have no measurements to back up my claims. The effects I have reported are (or at least seem to be) real, but there is no clear point of delineation - I don't know exactly where soundwave propagation ceases to be the dominant force, and where pressure mode takes over. This will be covered in more detail when I get the chance to do some measurements and research.
..............

Steht bei Subwoofer

[doctrin]

Danke, sehr interessant

[Frankynstone]

http://www.decware.com/newsite/articles.htm

Daher habe ich meine Weisheit, dass man ein Chassis erstmal in die Hand nimmt und damit Musik hört. Wenn es bescheiden klingt, baut man damit nicht.