Front vs. Rear Port

Duke spells the truth.
The whole idea of rear port is to isolate woofer resonance.

Hi Duke, I notice little diferance with floor materials but I do include a damping pad if one has a very live room also inc cones or feet if one has deep pile carpets.Problem is spacing of port from floor and designing cabinets to have the free space below for the port this causes extra work for you will need funky bases or arched plinths,more careful tuning of ports, but it sure works. Loads the room with even bass pressure, allows easy of placement, systems so equiped can be placed near walls or far out in room since bass port is using floor for reinforcement I as a designer know distance from floor to port and can design for this with front or rear you dont know distance to walls just floor so loudspeaker with front or rear ports needs more careful room placement.PS if you use a bottom port in one of your designs I want a free T shirt .lol

Interesting about the bottom ports. May be what I need as the only (WAF) acceptable location for my speakers is in the corners of my room. My B&W DM580's are boomy, even with old (clean) socks stuck into the ports - I lost the foam plugs. What are some bottom ported speakers <$3-4K that will give me tight bass in the corners?

Radu

Hope I'm not hijacking here, but a related question on downward firing ports and woofers:

Does a downward firing woofer and port (i.e. all meaningful output below, say 100hz or 150hz) greatly reduce or eliminate the so called "Allison Effect" and make the speaker's in-room response much closer to its anechoic performance? It seems like any speaker (ported or not) using a woofer crossed low enough would benefit from a downward firing scheme. Is this right?

Marty

JohnK, thanks for sharing your experiences. I built a large Snell Acoustics Type A-inspired system with downfiring woofer and port nearly twenty years ago, but I only used it in one room, which had a hardwood floor.

Raduray, there's more to a speaker working well in a corner than just the porting issue. You see, the walls that intersect right behind the speaker will act sort of like a giant horn and redirect energy that normally would have spread out to the sides, sending it towards the listening area. The result can be coloration if the speaker is putting a lot of energy off to the sides at some frequencies but not at others.

Loudspeaker radiation pattern is sort of my hobby within a hobby. I'll e-mail you offline about something that might work in your situation, as it addresses the port tuning issue and the radiation pattern control issue.

If you have any questions that might be of general interest, post 'em here and I'll offer my $.02 worth.

Duke