Fast, fun, Inexpensive OB project

>>> I think a 4" fullrange will never have enough xmax to be used in open baffle.

Several on this forum seem to be using 4" Fostex drivers on OB with success... i can't seem to cut the holes to mount the drivers for fear it just won't work but maybe i should just try it and see for myself. I have a pair of Fostex 127e and TB Bamboos but they are in use at the moment. I also want to try the 6" Fostex 165k and 168z on OB... but they work so nicely in BIBs and ported boxes... The Betsy 8" works well on OB but it's designed for that.

Godzilla
 
is the Qts of a driver the only parameter telling its suitability for OB?
otherwhise, does a driver need something special to be OB when you are using it over 200hz??

i remember Gainphile tried the TB bamboo on his blog and was disappointed on farfield listening, hopefully he will chime in.
everybody seem delighted by the FF85k which should be around 90db sensitivity.
 
Alternative H.F. driver for the Manzanita

Great to see so much continued interest in this design...

Thanks again to Michael and all contributors....

As far as alternatives to the D3800 go.... I have tried several different drivers.. some pretty far fetched.... some that appear to be excellent posibilities... But so far have found nothing that equals the D3800. Which has gotten me to thinking about why it does so well... and like most speaker system designs there are a lot of things... interactions going on... some obvious... some not so much so.

Keeping my goal of crossover simplicity in mind... especially minimizing componets in the signal path... it turns out the combination of baffle geometry, Open Baffle (partial cardioid actually) F equal and F peak values, natural driver roll offs, directivities and sonic signatures all come together to function as a coshesive, integrated summation. Some of this was planned.... engineered if you will ... some just plain luck. What is easy not to appreciate is the simple idea that these two particular drivers sound good together. Complimentary if you will. You just can not measure or predict that. I don't mean to imply there are not other, better posibilities out there.... actually hope there are as the cost of the D3800 is quite steep.

To my ears ... the D3806 seems to harmonically match the Peerless woofer, can play down low and loud enough while still providing excellent resolution and a surprising amoung of upper "air". Not as much "air" as say the Seas 27TDFC.... but the 3806 lower end performance so improve the overall sound quality ... the slight loss of "air" is a good trade off.

One inexpensive driver I have used is the HI-VI DMN-A (which I picked several up on sale for $17 each IIRC)... has the low end and midrange on a par with the D3800. But to get the "Air" quality of the D3806... I needed to add a 3/4" small format tweeter and of coarse the added crossover complexity. The combo was close ... but not as cohesive over all. This is typical of various drivers or combination of drivers so far tried. I think the Scan Speak "SD" motor has a lot to do with why the D3806 sounds so good.

I will love to hear about what others find promising. Just wish there were more of the D3806 equiped systems out there to use as a reference.
 
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Thanks John. Yes I agree that the D3806 is hard to beat. But it should be, at that price! Great driver.

If someone can find a FR driver that works well (maybe not as well as the 3806) it's going to make the design a lot more accessible. And the D3806 can be a future upgrade if so desired!

I may rebuild my pair after the new year and give a few drivers a try. My eye is on the TB 3" bamboo. :)
 
Sorry for going OT but it was such tempting and so much fun to give it a try :)

Here what I found to be working as an XO for the SLS and the NEO3-W on dipole horn.



XO_schematic_NEO3-W_SLS-naked.jpg


This is for the SLS *naked* meaning without any baffle !!!
Bass in my room was such strong I had to tame by a severe low shelving - no idea how you guys manage without that ???

If the inductor for the Peerless SLS is any higher (12mH or 22mH as suggested by pano and John) you have to re-adjust the 12 Ohm resistor for the tweeter accordingly – or even better, put a shunt to ground to form a voltage divider.
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-4.html#post2011071
*And* you have to apply even heavier low shelving (in a room like mine)!

The NEO3 has some pronounced sonic pattern that at first playing makes anything sounding "chchchch" – seems being stronger with the non-PDR version but improves during brake-in
;)

Don't know how long it takes for complete break-in - so some minor adjustments may be necessary in the end.

Will be back with a XO for the 12" Peerless in the Manzanita baffle if I can find an alignment (might even work as is with some slight changes in the notch filter part)...

Have fun!
 
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PB290110.jpg




To complete - here what I found working as a passive XO for the 12" Peerless in the Manzanita baffle / B&G NEO3-W in dipole horn


XO_schematic_NEO3-W_SLS-baffled.png






– should do as well for the SLS in the mini-Manaznita baffle of jerome69 shown in :
http://www.diyaudio.com/forums/multi-way/110583-fast-fun-inexpensive-ob-project-3.html#post1989499

I also picked up your suggestion for the notch to steepen the slope of the SLS in XO region – works well sonically for me too – thanks !

Lower parts count XO's I sadly could not get working...

Bass in my room was strong again and I had to tame by low shelving – as already said.
The NEO3's pronounced sonic pattern has considerably improved until now too
:)

Michael
 
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