Moving a port to front

[Gollum]

Hi,

I'm the guy building the BAMTM at this thread . My question is simple : is there any impact on the frequency response to move the port from the back side to the front ? I know it's not a good idea to place the port right behind a woofer because too much midrange will come out. But what about placing it on the baffle instead of the read panel ?

Thanks for your time !

Dino

[GM]

Greets!

Depends on the design. Not seeing enough info to say what all differences there may be, but most vents are on the baffle and can be damped as required if they contribute too much audible BW.

GM

[sreten]

Hi,

http://www.zaphaudio.com/BAMTM-cad-vented.pdf

Are you following this ?
By his own admission box design is not Zaphs forte.

Why do you want to move it to the front ?

/sreten.

[Gollum]

sreten,

it's exactly what I'm building, but with on small change : the baffle won't cover the top half of the cabinet only, it will go from top to bottom, 44" long.

The only reason why I want to put it on the baffle is the look. I plan to place it around 12" from the base. Does it sounds like a bad idea ?

BTW, maybe Zaph is not that good with box design, but I've learned on this forum that you don't change a design if you don't know what you're doing... and I'm not sure I do right, so I need help here !

Thanks for your time,

Dino

[sreten]

Hi,

Well the bracing arrangement in the box could be improved.

If the box is completely lined with foam etc including the front part
then port front or back 12" from bottom will not be critical. You can
then tune the bass to a degree with the amount of light stuffing
placed in the top half of the enclosure.

Good luck with it - seems a great design for the price.

/sreten.

[Gollum]

sreten,

you won't go away so easily ! Please explain yourself, I need to learn !

1) What can be improved in the bracing arrangement ? The more the better, no ?

2) I don't plan to stuff the cabinet too much. In what it changes something to port placement ?

regards,

Dino

[318Shawn]

How much in duty have you guys had to pay when ordering stuff from the US? I am trying to figure out if it will be easier to try and find stuff in Canada or just order from PE or Madisound.
Shawn

[Geek]

Hi Shawn,

Most items are NAFTA duty free. Have them send it USPS instead of courier, because a courier will nail you a fair hefty brokerage fee wheather there's duty on it or not.

The most I have been hit from post is the odd $10 "handling fee" fron CCRA. But this only happens when they send it under my company name.


As for the topic, front ports are MUCH less critical with room placement. You lose some bass "room gain" with the port on the front, but you won't spend an hour looking for the spot where your bass doesn't sound like mud either

Cheers!

[Gollum]

318Shawn,

With my current project (Zaph BAMTM), I've ordered from Madisound and Parts Express. Both were send via USPS Airmail. Here is the breakdown of each order:

Madisound: (value of duty: 135$)

Duty: 0$
Excise Tax: 0$
GST/HST: 8.15$
PST: 10.80$
Handling fee: 5$

TOTAL: 23.95$

PartsExpress: (value of duty: 52$)

Duty: 0$
Excise Tax: 0$
GST/HST: 3.12$
PST: 0$
Handling Fee: 5$

TOTAL: 8.12$

You always pay Handling Fee and GST (6%). I don't know what is PST though... and as Geek said, forget UPS or FEDEX from USA, except if the sender gives you the insurance he covers all the charges.

Hope this help.

Geek,

Since the speakers won't be placed in the best spot, I think you have a good point. Room gain from placement will be good enough without adding more with port.

Thanks for your help,

Dino

[318Shawn]

Thanks for the info guys, sorry to hijack the thread.
Shawn