Port reflex or sealed

[mark.carline]

I am currently building a three way system and the bass unit will be the following:

http://www.focal.tm.fr/gb/compo/woofer/10w6411.htm

The *internal* dimensions of the box that will be housing this unit are as follows

Depth: 264mm
Width: 264mm
Height: 564mm

This gives me an internal volume size of 39.3 ltrs.

My next question is simple - Do I fit a port relex on it or not?

I already have an excellent sub so i'm not too worried about getting to those low frequencies but the speaker will be positioned in the corner of a room and my experence of using ported speakers in the corner of a room is that they can tend too boom too much.

I am after a real tight punchy bass that doesnt sound too windy which I find can be a problem with vented bass speakers.

I will be making sure that the internal walls of the sub are covered in achousic laminate panels and I am also tempted to have around 2-3 inches of concrete at the bottom of the speaker to give it more weight (I may even put some lead lining around the walls (in true JM Labs tradition!).

Any thoughts ??

[sreten]

Really depends on your c/o arrangements to the sub.

sreten.

[mark.carline]

yep I has tried the theory in WINISD (See picture below - white is sealed and Green is vented).

Does anyone have any thoughts as to the sound difference that I will hear ?

These will be a main pair of speakers used in a 5.1 system for Home Cinema and also a normal pair for music.

[mark.carline]

p.s. what size of the vent do you make it ??

My calcs are telling me for a port thats 7.5 cm in dia I need it to be 17.4 cm long.

[mark.carline]

Also!!

Any thoughts on if the port should go on the back or the front of the unit ??

[5th element]

Id suggest sealed if its going to be crossed to a sub, if it matches well with the subs roll off. Do you happen to know what order filter is on the subs low pass??

Port front back/ neither really I dont think makes an iota of difference. The general reason for ports on the back is minimised chuffing heard at the listening position if they are going to chuff.

[sreten]

Originally posted by mark.carline
yep I has tried the theory in WINISD (See picture below - white is sealed and Green is vented).

Does anyone have any thoughts as to the sound difference that I will hear ?

Well driven full range with a sub in parallel, assuming the sub
rolloff is 2nd order Linkwitz/Riley and can be set low enough,
(most can't) sealed c/o frequency is 50Hz, reflex ~ 40Hz.
(I'd recommend low port tuning, around 32Hz)

Given your placement I'd go sealed, if the speakers can't keep
up level wise with the sub you can always add the ports.

sreten.

[mark.carline]

My sub consists of the following amp:

http://www.bkelec.com/Diy/bsb500.htm

and speaker which is a peerless 830500 XLS 12" :

https://secure.wilmslow-audio.co.uk/..._Units_13.html

Which is in a sealed box thats around 36cm x 36cm x 45cm.

The sub sounds great and gives a real punchy feel.

The amp on the sub gives me the option as to which frequency it crossovers at between 40Hz to 240Hz

p.s. Pictures of my sub / home cinema are on the following link:

http://www.avforums.com/forums/showt...5&pagenumber=1