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-   -   Help from the speaker experts. FE167E (http://www.diyaudio.com/forums/full-range/60515-help-speaker-experts-fe167e.html)

Wella 10th July 2005 07:50 AM

Help from the speaker experts. FE167E
 
Ladies and Gentleman, I'm looking for help...

I've bought some Fostex FE167E drivers and im now trying to design a cabinet to put them in. Let me add that im a beginner!:xeye:

I was originaly intending to use the fostex recomended enclosure but ive been told that it maybe too small. Plus ive noticed bob brines uses a larger enclosure (his smallest is 24L i think) and ive been told from anouther site of someone using a 21L enclosure with success.

So ive decided to use a 21 L enclosure, make it tall and thin (for aesthetics).

I entend to use baffle step correction compensation too.

Ive attached a pic of my plans so far and im looking for criticism, help, ideas, etc....

Any help will be much appreciated.

Thanks.

Wella

Wella 10th July 2005 09:03 AM

the pic
 
2 Attachment(s)
the pic

http://us.f1f.yahoofs.com/bc/7c2636b...cFN0CB0kqLbjZq

joensd 10th July 2005 09:22 AM

Hi,
the tuning and all looks alright.
I think you got messed up with internal/external measures of the speaker? 560*170*220 should be internal right?

Have a look here for some inspiration. (should be ~20l+ as well)

I built the 15l-recommended and well the tuning is alright but yes for most recordings a bit on the thin side when it comes to bass.

IŽll be either complementing with stereo subs or building a ML-TL ala Bob Brines FT1600. Building a stand for a bookshelf or building a bigger speaker in the first place is no big difference is it?:D

greets&happy listening

GM 10th July 2005 03:33 PM

Greets!

Hmm, tall and thin, eh? Since even most old vinyl has strong content to 40 Hz, this seems the 'no-brainer' Fb choice to me, so using your 374 cm^2 (~57.97"^2) CSA (cross sectional area):

L = 50.375"
zdriver = 17.375"
zport = bottom exit
rp = 1.5"
Lp = 2"

Space it up off a massive plinth as required to get it to ear level. With 2-3 ohms series resistance/BSC it should be solid to 40 Hz at modest SPLs if not placed too far out into a large room.

GM

Wella 10th July 2005 03:54 PM

hiya,

yer the only dimensions I have worked out so far are internal so all dimensions should are internal.

Thanks

Wella

Wella 11th July 2005 06:53 AM

ok you lost me there,
 
Sorry GM but im new to this and you kind of lost me... Infact you completerly lost me...

Hmm, tall and thin, eh? Since even most old vinyl has strong content to 40 Hz, this seems the 'no-brainer' Fb choice to me, so using your 374 cm^2 (~57.97"^2) CSA (cross sectional area): The cross sectional area of what is 374 cm^2. Are you saying that it has to be tall and thin or that it doesnt. Im sorry but without understanding the math your "no brainer" isnt clear to me...


L = 50.375"
zdriver = 17.375"
zport = bottom exit
rp = 1.5"
Lp = 2"
:
Yep you got me there too im afraid. Im now 100% lost

Sorry for my ignorance, im very new to this but wanting to learn.

Paul
:clown:

joensd 11th July 2005 09:46 AM

I guess from your picture GM thought you like the enclosure to be tall and thin.

The values given mean:
L: inner lenght of the enclosure
zdriver: position of the driver measured from the top
zport: position of the port measured from the top(here:50.375")
rp: radius of the port
lp: lenght port
Cross-sectional-area:(wide*depth)
(S0/SL in the drawing below)

have a look here for a better understanding:
(and the whole webpage if you wish:http://www.quarter-wave.com/)

http://www.quarter-wave.com/Models/Box_App_Notes.pdf

greets

Wella 12th July 2005 09:09 AM

So do people think im on the right track?

Are my plans, being fairly tall and thin, still going to be ok?

Wella

GM 12th July 2005 02:53 PM

Greets!

No need to apologize! I see Jens explained what it all means. Your first post 'sounded' like you had at least some knowledge of speaker design and since you had done some research I assumed you had at least been exposed to MJK's MathCad WS and many of the various pipe designs already documented on the various forums/personal websites.

Quote:

Sorry for my ignorance, im very new to this but wanting to learn.
Studying everything on MJK's and Bob Brine's site is a great start!

Quote:

Are you saying that it has to be tall and thin or that it doesnt.
No, it doesn't, but you both stated a desire for and depicted a tall/thin design, but in reality it's a typical ~small box speaker with a massive 'stand' attached. My suggestion OTOH is a true tall/thin pipe design that will perform somewhat better down low one optimized with either some series resistance and/or BSC and typically 'sounds' subjectively 'tighter'.

Quote:

So do people think im on the right track?

Are my plans, being fairly tall and thin, still going to be ok?
Hmm, this indicates to me that you're really not interested in learning about speaker design or building a true tall/thin (pipe) speaker, but just looking for some validation of your design, which Jens has already done, so build and enjoy.

GM

Dumbass 12th July 2005 11:58 PM

Build GM's design. It would be hard to beat for that driver.

You can build the downfiring enclosure like this:
http://www.quarter-wave.com/Gallery/JMLTLd2.jpg

Or you can put it on stilts, like this:
http://www.stat.ucla.edu/~erickson/jpgs/trapmltl.jpg

Since the port diameter is 3", I believe as long as you give at least 3" clearance below, it ought not change the tuning of the enclosure much if at all.

I am a proponent of "wide and shallow" enclosures, as it lowers the baffle cutoff frequency. I have also listened to a pair of the Jordan JX92S in the VTL enclosures, and found the stereo imaging excellent.


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