Cabinet Alignment



I tried a few different cabinet alignments based on classical mathematical models.  Vance Dickason's Loudspeaker Design Cookbook almost promulgated the superior transient response of one alignment over another.  I tried an SBB4 with a 3" diameter port, and a QB3 with a 2" diameter port.  I couldn't hear any difference between the two cabinets.  The SBB4 had a slightly higher F3.

My conclusions are twofold.  First, if the port doesn't whistle or chuff, then don't worry about the port diameter.  Second, the traditional alignments were created via manual mathematics and a great deal of brainpower.  With box design programs such as LspLab anything is possible.  While there is some truth about the correlation between alignment and transient response, the discussion is largely subjective with respect to preference.  

I have heard the SS8545 in my home in a 22 liter enclosure that produces an F3 of about 40hz.  I have also heard the SS8545 in a commercial TWW (tweeter, woofer woofer) enclosure (costing $10k) with an advertised F3 of 32hz.  The sounded tighter and cleaner in my 22 liter cabinet, but the difference was slight.  Some folks would prefer the deeper bass afforded by a larger enclosure.  I prefer the clarity and tightness afforded by a moderately sized enclosure.

Driver design and cone structure are probably more important than alignment when crisp transient  response is considered.  A motor with a short throw in a "to big" box will produce a subjectively loose response.  This is because cone excursion is beyond the linear Xmax, and distortion will occur.  Even good drivers (SS8545) with long throw motors will vary somewhat in bigger/smaller enclosures.  Smaller/moderate cabinets produce a tighter bass.  Larger cabinets produce deeper bass.