Is there any problem with running a 12" woofer wide open to an Fostex Fe126e.The woofer will be in a BR box and the Fostex Fe126e will be mounted on top of the woofer box in an open baffle...do I need a crossover?
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.
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.
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.audiophile36 said:
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.
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.
Scottmoose 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.
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'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.
My driver holes are not perfect, but I just drill a hole on inside of the circle so the jig saw blade can get in and cut from there.
Scottmoose said:
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.
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
J & G
JandG,
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.
cheers.
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.
cheers.
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.
My next OB I am building will be for large scale dynamics, Bi-amped again of course.
The 126 is really going to suffer with no XO at all in an OB... your best bet is bi-amping with a 1st or 2nd order PLLXO built into your HF power amp. The woofer is less critical.
dave
audiophile36 said:
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.
Bluto
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.
Bluto
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