Challenger - 8" silver flute / SB waveguide

[HIFY GUY]

Re: Challenger - 8" silver flute / SB waveguide

A speaker bud sent me that link the other day. I didn't have much luck with vifa XT combo, it was flat enough, just didn't like the middle.
I couldn't begin to explain how the SF works, I know the it's a little different than most mid woofers - springy with a big magnet.

[bill poster]

Re: Challenger - 8" silver flute / SB waveguide

http://www.stereomojo.com/Tanto%20Review/GemmeAudioTantoReview.htm

These commercial speakers use the same units and claiming some crazy bass extension figures, what cabinet design are they using ?

quote

"Without revealing too much secret information, Vflex is a twist on the ‘ole bass reflex design. While the tweeter is sealed, the rest of the tower is a ported design, but the bass is loaded in a rather different way.

Mr. Gaboury is careful not to reveal all his secrets, but I managed to extract this from him; “In a reflex enclosure, the air inside the enclosure doesn't move much, and the cone acts on the trapped air mass, and that mass releases its energy through the vent, like a spring or sling shot, and the tuning or loading is typically calculated to match the resonance of the system, which is the point where little energy is needed to create movement. It's really a matter of mass because the cone is loaded on a narrow band. In the Vflex, we add to the mass a force factor. The air mass is put in movement through acceleration and deceleration, generating force along the chain, where each link is a spring, accumulating and releasing energy on yet another spring. This succession of springs moves the air inside the enclosure with high torque. Each high pressure zone is balanced with a low pressure zone somewhere else in the system, and pressure is always moving from one end to the other, in perfect synch with the loaded cone, and the springs system keeps the woofer loaded on three octaves"

[HIFY GUY]

Re: Challenger - 8" silver flute / SB waveguide

That's about double the size of the vented box in the middle post #23 pic, probably sound about the same since the woofers don't push a much air, not much cone movement at all. I got word that they can work in 1.5cf each - 3cf total.

Let me know if you get curious about the 6.5", 8ohm version, that's one crazy little woofer! I have a few xo designs, they all sound wonderful.

Thanks for the HW08 link, will order a pair soon. This must be it: http://www.parts-express.com/pe/show...number=270-308

[ryanbouma]

Re: Challenger - 8" silver flute / SB waveguide

Hey HiFy Guy.

I think I used 25L for both. They were the 8ohm.

You can get the waveguide from PE. It's the HW08 or something like that. Just mill the threaded throat off and open it up to the diameter of the tweeter diaphram and surround. Really improves that tweeter.

I sorta wish I finished this design. I went 95% of the way, just never really did any final measurements.

Enjoy your new speakers!

[HIFY GUY]

Re: Challenger - 8" silver flute / SB waveguide

btw, this fellow was nice enough to help with the xo, info here:

http://jaysspeakerpage.webs.com/simulations

I may have the parts to build the wave guide, did you use the 8ohm SF version?

[HIFY GUY]

Re: Challenger - 8" silver flute / SB waveguide

Ryan, I had a bit of fun with the SF's 6.5 and 8" . (Pic)

Hey question, what's the volume of the double 8" box?

btw, I might have to try your project next - have the parts (if that's a SB29).

[Ryan]

Re: Challenger - 8" silver flute / SB waveguide

I love the look , great build!

[ryanbouma]

Re: Challenger - 8" silver flute / SB waveguide

You could just do it in a tower or something. I did this before the SEOS was available. I think the SEOS builds are better, but they're also 14.5" wide. If you need narrow, there are a few 8" ones. This one isn't bad, but it does have vertical issues. It's a 1000hz cross over, so not bad.

[CZ Eddie]

Re: Challenger - 8" silver flute / SB waveguide

This is a really cool build!

Are there any other designs like this, but in a 1.2 cu.ft. vented enclosure, tuned down more around 40-60hz?

[ryanbouma]

Re: Challenger - 8" silver flute / SB waveguide

Oh ya, and I measured the 2.83V SPL using REW and the FR hovered right around 93 or 94db at 1m!! That's into a 4ohm load though. Well, 4.5ohm :o :D

[ryanbouma]

Re: Challenger - 8" silver flute / SB waveguide

Yup, it's well protected. That's part of why I originally went with 1500hz xo, but after I ran compression testing, I realized this thing can take it. I did 128watts with a single 5.9uF cap and it didn't flinch. So with 4.7uF it should be even safer.

The top end doesn't bother me at all. It's 4 or 5db hot, but I can't hear it way up there. My db scale is much more course than a lot of people show ;)

The whole response smooths out at 15 degrees big time. Gotta get outside and measure at 2m. Then the null will move into position and I can get a polar response.

[isaeagle4031]

Re: Challenger - 8" silver flute / SB waveguide

Is that enough to protect that tweeter down that low? It seems to me that it may need a bit more and you may need to tame the rising response at the top end as well.

[ryanbouma]

Re: Challenger - 8" silver flute / SB waveguide

Ok, I decided in the end this could be improved. And I was able to improve it.

Still haven't made it outside for some real good measurements. But here is one at 1.5m:



This thing really needs to be measured at 2m. Then it'll be even flatter.

The xo (even though the null doesn't indicate it) is now at 950hz and there is more BSC.

And look how cheap this cross over is

[ryanbouma]

Re: Challenger - 8" silver flute / SB waveguide

Did u try a half ohm resistor before and after, splitting the value? Maybe a shunt resistor instead? I don't know why, but the cabinets look huge. I like the finish.

I tried playing with a .5R. Works good in front. I think it'll become permanent on the passive version.

Yesterday I was looking at them more from a WAF factor. They seemed small to me :eek: They are big compared to your average MT, but for three 8" holes, it's as small as you can get. Smaller than most any 3 way.

[ryanbouma]

Re: Challenger - 8" silver flute / SB waveguide

that is the flatest fr i have ever seen.

Thanks! But once you look here it won't be: http://www.musicanddesign.com/NaO_NoteDetails.html

I can't really be proud of the flat FR. Anyone can do that with a minidsp. Active doesn't seem very popular on these boards for some reason. Arlis, you really should consider getting one for your 3-way build. It'll cost less. Do the MT with passive and the WM with active. Hard to compete with the ease of design. Only drawback is the extra wires and amps.