Pioneer 8" build, the Chang variant

[gychang]

Originally posted by Godzilla
Hi Gychang!

I am curious how you feel about the sound of the B20 in this new cabinet. The cabinet can be key and the way it enhances the sound will need description in loving detail when you get a chance.

Thanks,
Godzilla

I can't wait to hear them, but since I plan to do this one right, I will have to put on a proper finish followed by mounting the driver etc. At earliest probably in 2 wks due to my regular full time job. (at times like this I wish I was unemployed...)


I have been told by a reliable source, a tweeter from partsexpress
http://www.partsexpress.com/pe/psho...FTOKEN=83033797
will work well with 4uf capacitor on + side of the tweeter, that will result in crossing at 5KHz. when used with the Pioneer. No other crossover needed.

Is it right that crossover is not needed?

thanks,

gychang

[Godzilla]

>>> 4uf capacitor on + side of the tweeter, that will result in crossing at 5KHz. when used with the Pioneer. No other crossover needed.

>>> Is it right that crossover is not needed?

This is the technique used by most every fullranger (builders/hobbyists whatever you want to call us) out there. We let the main driver run all out without crossover. All you are doing is adding a helper tweeter. I do the same thing with the B20 and the piezo tweeter but I use a different value cap (and resistor). The tweeter you reference does not require the resistor. So a single capacitor (of desired value) would basically roll into the response of the B20 at a mild 6db per octave. You are essentially blending the two drivers together rather than choosing a crossover point and building a crossover for both drivers to meet at that point.

I think you should try a few other capacitors with different values to make sure 4uf is ideal. It may be perfect or it may require a bit of tweaking.

How are you thinking of mounting the tweeter? Front? Back?

Godzilla

[zayne742]

Also, a little trick is to wire the tweeter in reverse of the woofer, puts it out of phase and gives a smoother response when running with a full range driver. You may want to also check out:

http://www.partsexpress.com/pe/showd...number=275-070

Very smooth response. Currently using this in my BIB's using the Pioneer 4.5" fullrange, same as your other BIB's. I love this set, great for music, theater, you name it.

[RKH]

Originally posted by zayne742


Very smooth response. Currently using this in my BIB's using the Pioneer 4.5" fullrange, same as your other BIB's. I love this set, great for music, theater, you name it.

Sorry if off topic ... please move if required.

I've looked at the 4.5" Pioneer fullrange a couple of times. What BIB cabinet dimensions did you use? The specs are similar to the FE103 if I recall correctly.

Cheers,
Ryan

[zayne742]

This was dervived from GM's formula.
Fs 70
Vas 0.31
Qts 0.35
Line Length 96.175
Folded Height 48.088
Vb 1.669
Sm 59.977
Depth 9.210
Width 6.512
zdriver 20.870
a-b-c 4.605

Pretty much the size mine are, Gychang's were:
"El Cheapo speaker BIB demension: (Scottmoose)
Try a 120in line length, driver at 24in down from the sealed end, 70in^2 terminus area. Inside demensions: 7x10, height:60, speaker placement: 24” from top to middle of the speaker, inside slanting baffle ends 5” from the floor and 5” from front and 5” from back."

Mine sound great, not sure if there is much benefit from the taller, with a bigger terminus.

[Kensai]

The taller version is tuned lower, though I'm not sure about the larger mouth. Generally, following GM's formula the mouth will shrink, marginally, the lower you tune a BiB. I think Scott custom calc'd that one for gychang and it was pretty early on, too, so he may have had different goals in mind at the time.

Scott?

Kensai

[gychang]

Originally posted by zayne742
You may want to also check out:

http://www.partsexpress.com/pe/showd...number=275-070

Very smooth response. Currently using this in my BIB's using the Pioneer 4.5" fullrange, same as your other BIB's. I love this set, great for music, theater, you name it.

That tweeter looks nice, do u know if it will work well with the 8" Pioneer with a 4uf capacitor?

thanks,

gychang

[Godzilla]

http://www.zaphaudio.com/tweetermishmash/

gychang... have a look at the link above.

Any tweeter will work. Its a matter of choosing one and then going about optimizing the performance with the B20. Every tweeter will add its own flavor. Just dont get a spitty bright sounding tweeter... unless you like that kind of sound.

I also like the piezos out there with the B20. Pick a piezo, any piezo. But i understand many simply dont like the way they sound. When using the piezo you are really just extending the response of the B20 and not so much changing the B20s overall sound because the crossover is really high - 20k or so and blending back into the B20s response. But using one of the other tweeters and a much lower crossover point will change the sound. There is no right or wrong only different options to try and enjoy.

No matter what you do with the B20 it will never be state of the art sound. I like to keep it simple with this driver and love how easy it is to get very good sound from it thats very relaxing to listen to for long periods without fatigue. The B20 has been my office system for close to two years now and i always enjoy their sound thruought the entire day.

Godzilla

[Variac]

I finished the BIB cabinets for my Pioneer B0FU . I still need to cut the driver openings and to do that I need to find my circle jig for the router...
Also need to add the damping..

IT will be 2 weeks before they are finished for a report as they are at a friends, and he has no time to work on them this week.

The guy I know who likes these drivers uses a cheap car audio dome crossed with a 1 mF cap. (EDIT: I meant 1 uF)

The tweeter decisions are the same for me of course....

[zayne742]

Originally posted by gychang



That tweeter looks nice, do u know if it will work well with the 8" Pioneer with a 4uf capacitor?

thanks,

gychang

Do not see why not. Mine are crossed @ 2.5k with a 8uf and a 0.5mh at 12db. Using a 4uf would cross them over at 5k @ 6db. They are extremely smooth for my setup. Not sure how they will work with the 8", but many others have used them with high satisfaction. I have been thinking about crossing mine a bit higher, so 5k may be a very good start. Good luck, and keep posting!
May have to start a new thread soon, when my next project goes under way. Not to go off topic, but here is a pick of the driver.