i built these a while ago and

[roystr]

i was just reading about a slightly different ported loudspeaker and the guy stuffed/blocked off the port for better midrange,,he said he could get away with this because he used a subwoofer to play the lows that the other speaker wouldnt do as well anymore.because of the blocked off port.

so my question is,,can i gain some improvement by blocking the port in this type of speaker?
also,the guy that builds them wood bullet things for the center of the cone?? anyone know if they are available for the 167?? and what EXACTLY do they do??

yes,ive been out of circ for a while( no laughing Tim)

thanx guys,

roy
BTW: i still love these things,though i still havent made them look any better. the highs are just a bit bright though,,im thinking of backing the treb down a lil on the reciever,but i dont want to lose treble per say,,just the shrieki-ness kind of shrill at the very top. im not an audio guy,so this is the best i can explain this stuff.(shrug)

[planet10]

I haven't met very many bass reflex boxes that i don't like better with at least a little bit of stuffing (in my room & to my taste)

As you increase the amount of stuffing in the port the box moves from being a BR to being an aperiodically loaded box. Add enuff that the port is completely blocked and it is sealed.

It is easier to mate an aperiodic or sealed box to a sub -- to a large extent because it has a slower & more gradual roll-off. It will start earlier thou.

An aperiodic box also tends to have a more benign & flatter impedance curve. As well the 1st derivative of the impedance curve is smoother. Generally this gives your amp a better chance to perform its best.

the guy that builds them wood bullet things for the center of the cone??

I don't actually make them (Scott does), but they are my product. Yes they are available for the FE167 (Scott has Bob Brines' inspired ML-TLs with FE167).



He came up with the yellow cedar ones because he felt they matched the cone so well.

Generalizations: The most important role the phase plugs play is to fill the hole left once you remove the dust cap. The dust cap traps & "amplifies" a soup can resonance inside the voice coil. Plugging the hole leaves no room for it to develop. (the quest that lead eventually to these was in an effort to kill an upper midrange resonance in the FE103 family that was most evident on male vocals)

The phase plug reaches up level to the surround and "bisects" the diameter of the cone (and in FE167 the whizzer cone). This pushes transverse resonances across the cone airspace by about an octave. The effect is to soften the top end at the same time as it extends it. Partially what is happening is that the on-axis beaming that happens as the frequency rises is "softened", improving high frquency dispersion. It still has the same HF energy, it is just spread out more evenly. The extension comes from pushing side-to-side comb-filtering up an octave.

Hopefully we'll get some comments from those who have heard them (and don't have the vested insterest i do)

dave

[roystr]

and is there minor surgery to install them? is there a guide to show how they would go into the 167?

thanx for the reply,
roy

[planet10]

Surgery is required.

http://www.planet10-hifi.com/pp-install.html

http://homepage.mac.com/tlinespeaker...4-surgery.html

dave

[roystr]

i guess the center dome must come out. but does the cone/funnel thing have to be removed as well?

thanx
roy

[planet10]

Originally posted by roystr
does the cone/funnel thing have to be removed as well?

Whizzer cone stays (pic above is an FE167)

dave

[roystr]

thanx
roy

[karma]

no just the dome or dust cover. the funnel thing is your voice Coil.


http://www.speakerbits.com/Default.a...coils&psize=20

cheers

[roystr]

i thought it was a Whizzer cone ?

all i do is remove the dust cover.then pop in the magneticaly held wood plug. is this correct?

[planet10]

Originally posted by roystr
i thought it was a Whizzer cone ?

all i do is remove the dust cover.then pop in the magneticaly held wood plug. is this correct?

Yes. (emphasis: Carefully remove the Dust Cap)

dave