First open baffle project

[Moondog55]

OK \
while I wait to accumulate funds for the big project I thought I would put together my first open baffle to see how they sound compared to a sealed box.
Searched thru the shelves in the garage and found some cheap drivers, I can't resist a bargain and these were $10 a pair, seriously not worth any more.
Using the published T/S parametres no realisable box would work so at a very high Q these should work in a flat baffle.
Started a thread in subwoofers but thats the wrong place,
Three and a half way, with the half in a sealed box rolled off very early first order'
So this is WW M T M W, Crossover is text book with listening changes, comment welcome as I have only a little experience developing x-overs, but I also used JBagby's excell work sheets.
This is a near enough good enough trial so not after perfection

[Moondog55]

I'm having trouble shrinking the scanned pictures to fit, my have to upload to one of the picture hosting sites, anyway it's started and about quarter way thru, pictures will have to wait while I go cook dinner

[Moondog55]

OK I opened a Flickr account, here is the first itteration of the crossover



http://www.flickr.com/photos/25510659@N07/2403004724/

[gainphile]

Good to know another aussie OB fan.

I envy your build! ... how does one make whole with router exactly? What is that grey 'guide' ?

[Moondog55]

OK access to Flicker files for open Baffle

http://www.flickr.com/photos/organiz...57604464939012

I bought a "Jasper " circle jig from Soundlabs, makes things a lot more fun, but I need to write everything down as the router works better with 1/2 inch bits and I have cut a couple of holes far too big because my arithmatic was out.
The more clamps I seem to have the more I seem to need,

[Moondog55]

OK here is a link to the thread that started this project

A frugal recycled sub idea

At least it keeps me off the streets and out of the pub

[Moondog55]

Hi gainphile, I saw those a while ago, have a pair of those cheap DS speakers myself, it's the pretend tweeter that lets them down.
I had a good tweeter cheap from a repairers surplus stock and tweeked the crossover on mine, BIG improvement
Just filled the box with polyfill tho, this experiment is my first real speaker in over a year and if I am really happy with imaging and overall sound I'll make the "Eathers"

Aethers: budget OB from Iowa 2007

[Moondog55]

I managed to get a little more work done today.

Playing around with various stains for the baffle

http://www.flickr.com/photos/25510659@N07/2412590789/

http://www.flickr.com/photos/25510659@N07/2413409800/

http://www.flickr.com/photos/25510659@N07/2413410638/

Settled on dark mahogany, I have to let it dry for 16/24 hours now before I can give it a coat of poly to seal the timber.

[Moondog55]

Here is a picture of the finished speakers.
http://farm4.static.flickr.com/3082/...885e65.jpg?v=0

Stupid beginners mistake made.

But I have a problem, in my haste to finish this project I have wired the 10inch 4R driver and the 2 X 8 inch woofers all in parallel and I'm presenting my amps with a 2 Ohm load which they do not like, I need to rewire but I lack the technical knowledge to calculate the correct inductor value to rewire in a cascaded topology, the 8's are rolled off at about 500 Hz with L/R2 2.65mH in series and 33uF in parallel and I have in mytoolbox some 5.6mH and 3mH coils.
What size inductor do I need to give me the boost at around 80 Hz?? and please direct me to any information so I can fill in the gaps in my understanding.
I must say I am impressed with the openness and depth of bass I have with this setup, especially when you consider the low cost of the drivers involved, $20 woofers and $7 midranges

[ttan98]

Originally posted by Moondog55
Here is a picture of the finished speakers.
http://farm4.static.flickr.com/3082/...885e65.jpg?v=0

Stupid beginners mistake made.

But I have a problem, in my haste to finish this project I have wired the 10inch 4R driver and the 2 X 8 inch woofers all in parallel and I'm presenting my amps with a 2 Ohm load which they do not like, I need to rewire but I lack the technical knowledge to calculate the correct inductor value to rewire in a cascaded topology, the 8's are rolled off at about 500 Hz with L/R2 2.65mH in series and 33uF in parallel and I have in mytoolbox some 5.6mH and 3mH coils.
What size inductor do I need to give me the boost at around 80 Hz?? and please direct me to any information so I can fill in the gaps in my understanding.
I must say I am impressed with the openness and depth of bass I have with this setup, especially when you consider the low cost of the drivers involved, $20 woofers and $7 midranges

Nice photos you much have put a lot of work into building the open and closed baffle cabinets.

I am taking another approach which is alot quicker and does look as nice as yours, I spend more time experimenting with open and closed baffle. I also use DCX2496(US$250) so that I do not spend lots of time tweaking the passive x-overs and lots of cash on the passive components.

So far I have tried these configurations over the last 6-12 months,

a. TWW similar to emerald physics CS2 ,OB
b. MTMWW similar to GR research,OB
c. TW similar to Jazz module, vented enclosure
d. Full range driver in Martin King cabinet
e. TMWW similar to Jamo 909
f. TW in a cabinet, similar to JBL outdoor pro speakers
g. WMTMW to be done.

I have NOT published my results because the cabinets do not look attractive, also I am only experimenting with what are combos I like most. More importantly I can understand when people are building and talking about any one of the above configs.

In the end I will build one or more permanent pairs which I can live with.

cheers.