Help! building acoustic suspension box

Rulo

Member
2016-04-24 11:12 pm
For unique reasons, I need to build a sub-woofer into a space that is 7 1/2"H by 18 1/2"W by 17"D that will only allow front firing. Because of the reduced space I will have to build a custom acoustic suspension box. Because of limited resources I will cannibalize an RCA WF60R, 60 watt sub to use the amp. I can fit a 6" speaker. I know I will not get wall shaking boom... all I want is to bring some depth to my Realistic Minimus 7, 8ohm speakers in a small living room.

2 questions:

1- Should I use one or two 6" speakers and why?

2- Any recommendations on REASONABLY PRICED speakers?

I can build the box but am a real novice on audio. Any help would be GREATLY APPRECIATED!
 
Hi,

That gives you about 0.9cuft internal volume. TBH I
suspect you want a budget rather than ideal solution.
Its not difficult to add bass to Mimimus7's.

I'd suggest two of these (look like Monitor Audio drivers) :
BS28-6P 6" Aluminum Cone Woofer 8 Ohm Shielded
(Why two ? The box volume indicates two would be much better.)
In your sealed box will be fine, but you could add a vent tuned to 40Hz,
around 2" diameter and 4.5" length, which is more about power handling.

FWIW the ideal solution is probably :
Tang Band W69-1042J 6"x9" Subwoofer
In your box vent tuned to 33Hz (2" diameter x 7" length).
(or 2.5" diameter x 12" length).

rgds, sreten.

Lightly stuff your sealed box, line the walls of a vented box.
 
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wintermute

Administrator
2003-08-03 11:43 am
Sydney
Rulo, they are acronyms from the internet age (or perhaps dating back to bulletin boards).

TBH = To Be Honest
FWIW = For What It's Worth

Basically just ways of saving on typing :) Not as bad as the textspeak we see from mobile phones!!!! I use them all the time.

Some others you may come accross.

IMO = In My Oppinion
IMHO = In My Humble Oppinion
LOL = Laugh Out Loud

There are plenty of others, but once you know they are acronyms it can be easy to work out from the context. If not just google what does acronym xxx stand for (where xxx is the acronym).

Tony.
 

Rulo

Member
2016-04-24 11:12 pm
Thank you. Since you're obviously a patient man let me push you limits. I understand a ported box would probably bring deeper bass and require less power, but, my understanding was that an acoustic suspension box would be "smoother" across the spectrum. True?
 

wintermute

Administrator
2003-08-03 11:43 am
Sydney
Speakers are all about tradeoffs :)

What the Sealed enclosure will give you is the best transient response. That is The speaker will return to rest after an excitation the most quickly in a sealed enclosure. This come at the cost of bass extension.

The ported box will give you the bass extention, but at the cost of inferior transient response. There are many possibilities for tuning that response though, and some will be better than others.

The compromises that one person can live with another may not be able to. It is a personal thing, which one really has to find out on their own (either by experimenting, or by listening to different types of systems created by others).

Tony.
 
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Assuming your measurements are overall outside dimensions, and 3/4" material for construction, you're looking at approx .9 ft^3 (26 liters) so either of sreten's suggestions are worth consideration.

For a small box & driver solution to "sub" woofer puzzle, I've always preferred sealed, but that's just one man's opinion.


For fill material, loose fibre dacron ( e.g. pillow fill) from a sewing crafts store should be fine.
 

Rulo

Member
2016-04-24 11:12 pm
You guys have been a special blessing to my ignorance. I will purchase the two (BS28-6P) 6" speakers SRETEN recommended. The specifications state it calls for .23 ft3 sealed enclosure so I suppose that for two I should make it .46 ft3. My only question left is how to calculate the volume occupied by the amp inside. Or should I put the amp in a separate box and just run the cable in? Once installed, the only thing visible will be the front of the speaker box so a separate amp box would not be an eyesore. Again, thank you for your interest and time.
 
Hi,

The two drivers will be fine in the originally described 0.9 cuft box.
Don't worry about the amplifier volume or the drivers volumes.
Sealed boxes are very flexible, you will get tight, dry bass.
There is no advantage to halving the box volume here.*

rgds, sreten.

* only makes sense for use as a bassmid in a sealed box
in an AV system that will be high passed at around 80Hz.
 
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^fair enough. I always thought that adding humble implied that one was
open to other possibilities, ie it is not necessarily a strong opinion. But
we are digressing. :)

Tony.

Hi,

True a digression. Seems I'm wrong. I use IMHO to indicate
a stronger belief than in IMO, being honest. Seems that I've
misunderstood its common usage, you live and learn.

rgds, sreten.