Full ranger and a woofer question


look the xmax of the Fostex,
try a closed box and cut 6dB ~300-400 Hz,
i don´t think an OB is a good idea for the 126.

If you take two of them you can build a horn
and you don´t need a bass.



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It'll depend on the woofer you select. You should be able to leave the 126 alone & let the woofer handle the LF to an extent, although it's not ideal.

FWIW, I'd do roughly what Martin does on his 2 way OBs; simple 2nd order circuit; high pass the 126 at 500Hz & low pass the woofer at 200Hz, both of which are typically good points to place an XO.
audiophile36 said:
Thank's Dave,

What kind of crossover should I use...I want to keep the Fe126e crossoverless?
Have you considered bi-amping? One of my systems is a similar setup (FE167E, though), with 4th order active Linkwitz-Riley crossovers before the amplifiers. Bi-amping is more expensive and complex, but does have many benefits - you should seriously consider going this way.

If you don't want to biamp, then I think hm is right - you should consider putting the fostex in a small sealed box to roll it off, and cross the woofer in at the right frequency. Getting the phase and crossover curves right for such a setup will require some careful design.
Scottmoose said:
It occured to me earlier, why a BR for the woofer? If you don't have the drivers already, I'd probably just go for Martin's 2 way (well, FR + woodfer) OB, or a variation on that. It won't lack for LF output, and the Eminence Alpha 15 isn't a pricey unit.

I want to go all OB but don't know how to cut holes larger than 6" because they don't make hole cutters larger than 6". I have a jig saw,but I don't know how to start a cut when trying to cut out a circle.
Scottmoose said:
Wouldn't that affect a 12in woofer in a box too?

I'm about the last person to ask in-re woodwork, but there are plenty of knowledgeable people here who'll be able to help you out. Make or buy a circular jig for your router would be favourite I imagine.

I was going to buy some vented partsexpress car subboxes with the holes pre cut.
Don't do that! You can do way better, sonically, which is what it's all about, right?

If you're struggling yourself, I'm sure there'll be somebody of a DIY persuasion nearby who can cut the holes for you, for a couple of his favoured beverages. Or you could grab a local cabinet-maker or similar -they're not going to charge much for cutting a couple of holes & certainly not more than it'd cost to buy a couple of PartsExpress cabinets. As you say you really want to go all OB, it'd be silly to let something as simple as cutting a couple of holes get in your way.
Thank's Scott I have seen some really nice OB systems and I actually have a OB system with Fostex Fe126e and they sound great except the low bass... mid bass and up is great though. I really want to place a 12-15" woofer on the same baffle as the Fostex.The reason I ask about the crossover is because I have owned and heard commercial speakers Like the EPI-100 and MMDecapo's run the woofer full range with a cap on the tweeter to limit bass from damaging the driver.I thought I could do the same thing except I wouldn't need a cap because the Fostex wouldn't be damaged by low frequency information.
This a 12" w/ 5" Seas w/ a 500-600 simple XO, single coil on the 12" & 2nd electrical on 5" which is I think a 3rd anyway with the small 10" wide baffle . You will most likely have to pad the Fostex a little, no big deal , just use Mills etc..or L-pad, transformer, etc..mine is -3db on the little seas mca15rcy, this is a great small OB mid by the way.It is very important to try & acousticaly alighn the drivers, I do it in the primative way shown. Just try the Fostex ran fullrange & 12 rolled & then HP the Fostex & listen. I would strongly suggest 500-600hz on the little Fostex.
J & G



2006-04-04 11:24 am

your horn looks very nice and interesting, where do get them? customised for you or buy off the shelf? How do you ensure compatibility?

just curious your woofers and other drivers just mounted on the baffle which is attached to an angle bracket(not large) standing on the floor, the vibration of the woofer and driver may cause instability to the baffle?
I thought a better mounted baffle may improve the sound.

More of a wave guide gig than horn. They are simple rubberwood salad bowls. I have many refined OB system's, these are not of course. I think they vibration gig is over rated in OB land. especially if they are mass loaded etc..I usually use 1 1/2" around OB woffers area's. These wave guides provides the best stage & detail I have ever heard in any OB . mid is padded -3db is all. hard to get OB bass wrong if good driver is used IMHO. Bi-amp-tri , single amp doesn't seem to matter, what matters IMO is a good behaved drivers that perform in OB..Once refined I will rebuil, paint & secure in rigid fashion & many other things. Most people seem not to choose to try & alighn driver's . My B200's were not near as good as the little Seas in OB. Keep the mid range baffle narrow & try to get a wave guide on it. It was a eye opener to what can happen. The OB magic stays & everything snaps into focus in very precise & eary way. No honk, no shout.
My next OB I am building will be for large scale dynamics, Bi-amped again of course.
audiophile36 said:
I want to go all OB but don't know how to cut holes larger than 6" because they don't make hole cutters larger than 6". I have a jig saw,but I don't know how to start a cut when trying to cut out a circle.

A 6" hole saw is a nasty tool; you'd better not be using a handheld drill with it. The way to do large holes safely and tidily is using a router with a circle cutter- Google "Jasper jig".
JandG -

Really happy to see this.

A bit over a year ago I started playing with all kinds of shapes based simply on experiments with a broken basketball some 30 years back.

My wife came home with a huge round plastic terrarium she found at a rummage sale. I immediately ixnayed that idea but 86ed the terrarium , tore it in half and started mounting different drivers.

As you say the sound stage was just amazing as well as detail. I also couldn't believe how much more SPL it appeared I was getting. I found smaller drivers caused an echoing effect as well as ruining the sound stage, instruments suddenly sounded as if they were 100 feet back from the vocalists.

I'm an ignorant newbee understanding only that these changes were causal to lack of XO and inappropriate drivers for the waveguide but I had at least learned there was potential to the concept.

Please continue to post progress, I think this is another one of those ideas that bring out hidden attributes of drivers.

Could be real cool looking as well. I did a bunch of drawings with different driver layout that looked real sharp but without understanding theory of XO they'll continue to just 'look'.

I think every DIYer is going to own a cheap lathe within the next year.