Designing for corner placement

odell

Member
2007-04-20 3:54 pm
I'm looking for some help - I have a pair of Fostex FE167E drivers which I plan to use in a small room (6' 3" x 9' 2" with 8' ceiling). The resulting speakers will need to be mounted on the short wall (over a desk so floorstanders are out) and I will be listening from around 2-3 feet. Amp is a Trends TA 10.1.

What I would ideally like to do is build cabinets with a triangular cross section which would then fit flush into the corners. What I don't know is how to adapt the cabinet design to work with the corner placement rather than against it. Should I go for a 15l cabinet as recommended by Fostex or something a little larger? How can I avoid boomy bass or other problems normally associated with corner placement?

Thanks for your help,

Mark
 

ttan98

Member
2006-04-04 11:24 am
Melb
odell said:
I'm looking for some help - I have a pair of Fostex FE167E drivers which I plan to use in a small room (6' 3" x 9' 2" with 8' ceiling). The resulting speakers will need to be mounted on the short wall (over a desk so floorstanders are out) and I will be listening from around 2-3 feet. Amp is a Trends TA 10.1.

What I would ideally like to do is build cabinets with a triangular cross section which would then fit flush into the corners. What I don't know is how to adapt the cabinet design to work with the corner placement rather than against it. Should I go for a 15l cabinet as recommended by Fostex or something a little larger? How can I avoid boomy bass or other problems normally associated with corner placement?

Thanks for your help,

Mark


try this site you may get a few ideas there.

http://www.pispeakers.com/

the designer/owner is very helpful.
 
How can I avoid boomy bass or other problems normally associated with corner placement?

Boomy bass is better than no bass :D

In all honesty I've had some full rangers sound better in the corner. The bass was slighly boomy but still better defined then what comes out of a lot of the subs these days. The FE167E normally has no bass anyways without a BSC circuit. So the recommended enclosure adapted for the corner might do fine with no correction circuit.

Corner horns are sweet. There is one using the FE167E on the Decware website, but it's big and heavy.
 
Jeb-D. said:
The FE167E normally has no bass anyways without a BSC circuit.

Maybe in your experience. Unless in a big room we found Demetri to have too much bass, Also keep in mind that pushed up against a wall a box has next to no baffle step. In a corner, and in a room this small, you want to design for very low Q bass if you don't want it to be boosted. I'd start out with a sealed box with Q somewhere between 0.5 & 0.577.

dave
 
Maybe in your experience. Unless in a big room we found Demetri to have too much bass

What is Demetri? I've only run the FE167E driver in the recommended bass reflex, which may be the reason for lacking bass. Excellent sounding with a BSC circuit, but very harsh and shouty without one. It also does pretty good without BSC compensation, when driven by an amp with a Zout of 8ohms and a Zobel.
 
Jeb-D. said:
What is Demetri? I've only run the FE167E driver in the recommended bass reflex, which may be the reason for lacking bass.

Quite a bit bigger than the 167 BR

http://www.planet10-hifi.com/boxes-fostex.html

We built a variation on the factory 15l (with lower tuning) for our initial 167e tweaking experiments.. It was good sounding and served th epurpose -- low bass is not its strong point -- and the current owner really enjoys them.

dave
 

odell

Member
2007-04-20 3:54 pm
Thank you to everyone for the replies - I'm new to this and you've been very helpful.

I don't expect miracles from this compromised room, but would like to make the best out of the situation. As far as bass goes my only reference is listening to typical small standmount speakers which list frequency reponse low numbers of around 65/70Hz. I wouldn't want less bass than this type of speaker.

I've plotted a couple of boxes in WinISD - a 15l sealed box gives a Q of 0.57, as advised by planet10. Am I right in saying that I could start sealed and simply add a port later if necessary?

Also, should I build the triangular cross section cabinet with a narrow baffle (equilateral triangle) or a wider baffle (right triangle) - what affect does baffle width have?

Thanks again,

Mark
 
odell said:
I've plotted a couple of boxes in WinISD - a 15l sealed box gives a Q of 0.57, as advised by planet10. Am I right in saying that I could start sealed and simply add a port later if necessary?

Also, should I build the triangular cross section cabinet with a narrow baffle (equilateral triangle) or a wider baffle (right triangle) - what affect does baffle width have?
The FE167E rolls off fairly high in a 15L sealed box - you probably won't get much bass at all. If you want bass and small, then you will need to go with BR, with a front port.

I have my FE167E in the recommended BR, and measurements suggest that they are at -3dB around 60Hz, which isn't too bad at all. Mine are pushed back against a wall in a room very similar to your's in size, and don't sound "boomy" to my ear.

The baffle width shouldn't have an effect if they are corner mounted - the wall will act as a baffle, extending the width. If you go with a right triangle, you will need good bracing to keep your front panel stiff. Other than that, you could probably just build whichever you think will look better.
 
cabbagerat said:
The FE167E rolls off fairly high in a 15L sealed box - you probably won't get much bass at all. If

I think you might be surprised. He is corner loading them and his room does not have a whole lot more volume then a car. Put a sealed box in a car and you get pretty close to flat to real low because of cabin gain.

dave
 

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odell

Member
2007-04-20 3:54 pm
I will try the sealed 15l box and see how it sounds after a few weeks listening.

If I don't like it I can soon convert it into a 15l ported box as Fostex recommends (albeit a different shape).

Could someone guide me toward a good primer on stuffing / lining sealed and ported enclosures?


Thanks again,

Mark
 
odell said:
If I don't like it I can soon convert it into a 15l ported box as Fostex recommends (albeit a different shape).

Could someone guide me toward a good primer on stuffing / lining sealed and ported enclosures?

If you end up porting them, i suggest a 2 1/2" port over the Fostex 2". Line the box walls with wool or cotton felt, fiberglass or polyfluff batting.

dave