Top Ported Speakers

[jtt1888]

Wondering if any of you guys have ever owned top ported speakers. I've a pair of ART Expressions that are top ported, should this theoretically mean I can place them very near the rear wall?

I've positioned them tonight according to a rear wall /side wall ratio that Cardas have published(1.62:1), all very complex but im quite happy with the results. The bass unit and tweeter are only around 450mm from the rear wall as this is governed by the sidewall distance according to Cardas.

The rear of the speakers are probably only 150mm out from the wall.

 

[rabski]

Top or bottom is frankly unimportant. I don't know the beasts in question, but the important point is whether front or back ported.

Back ported means some distance from walls is almost essential. Front ported usually means you can go much closer.

Of course, that's just the basics. There will still be interactions between speakers and walls. However, as a basic, rear ported equals need some space. Front ported equals needs less. Top or bottom ported equals zilch.

 

[budgetblown]

I know rear wall distance made a significant difference to the MC-5's I sold to Johnniebaby - but then the bottom port was rather closer to the floor than the ceiling would be to a top port speaker, so I would theorise that it would be less critical with a top ported speaker.

 

[jtt1888]

Thanks gents

 

[RobHolt]

If it's a tall cabinet then you could get some sonic difference in the way the port drives the room.

Ports are typically tuned between 35-70Hz and if the tuning is strong, the port position can interact with the main vertical room mode, since these can sit in the same region. Certainly on a floorstander the top/bottom port position can have some effect.

 

[jtt1888]

Rob

The speakers are standard stand mount height, just over 1m from floor level, my main concern was that although they are top ported, the port sits to rear of the speaker and only around 200mm from the rear wall, they are a bit unusual. I,ll try and add a snap for those not familiar with the expressions.