hm ... how to tune WO box at specific freq., lets say car peaks frequency ?

What is with that chambers ? how SPL depend on Volume of that chambers ?

2 djman37 ; please , can u look and send me to mail ? i am trying to contact Don , for 1 month on different mails , without sucess

Hi guys
I just talked to Don a few weeks back. His audio company is gone  :(
He is actually in the hospital (might be out now) he had some cancer removed and has had a rough time so I wouldn't be looking for too much response from him yet.
Don ported the WO by cutting a slot into the opening of the horn. It was pretty loud, but it was very much so a one note wonder.
We played around with moving the speaker baffle to try and get more SPL too. Angling the baffle is definitely not the way to go for SPL.
Other than that, the enclosure doesn't do too much as far as tuning goes. The bigger the back chamber the lower the tuning. The box has a pretty good in car boost around 40hz which makes it sort of generic as most cars cabin gain is near that freq. I wouldn't want to try and tune it as is to a more specific freq. I do have a design that we never built though that you might be interested in. The rear chamber is bigger and the chamber is ported to provide more gain at the tuning freq of the port. I will post that pic as soon as I can find my design notes. I would love to see somebody take that on.
To give you some ideas, I ran a WO 8" in a 240sx and was getting 150-151 db out of it
We also ran a 10" WO in a 4 door blazer and got similar #s with that.
We tried to go up to a 12" version and got to the mid 150s with it, but never really pushed hard to see what the design was capable of. I actually got off track at that point and started competing with the slot vented enclosures and straight rear loaded horns. They got big and ugly too lol.
What kind of car, woofers, amp, etc are you looking at putting together? I am sure I can offer some ideas on this one.

Robert

[quote author=musgofasa  link=1157009897/0#5 date=1157484255]Hi guys
I just talked to Don a few weeks back. His audio company is gone  :(
He is actually in the hospital (might be out now) he had some cancer removed and has had a rough time so I wouldn't be looking for too much response from him yet.
Don ported the WO by cutting a slot into the opening of the horn. It was pretty loud, but it was very much so a one note wonder.
We played around with moving the speaker baffle to try and get more SPL too. Angling the baffle is definitely not the way to go for SPL.
Other than that, the enclosure doesn't do too much as far as tuning goes. The bigger the back chamber the lower the tuning. The box has a pretty good in car boost around 40hz which makes it sort of generic as most cars cabin gain is near that freq. I wouldn't want to try and tune it as is to a more specific freq. I do have a design that we never built though that you might be interested in. The rear chamber is bigger and the chamber is ported to provide more gain at the tuning freq of the port. I will post that pic as soon as I can find my design notes. I would love to see somebody take that on.
To give you some ideas, I ran a WO 8" in a 240sx and was getting 150-151 db out of it
We also ran a 10" WO in a 4 door blazer and got similar #s with that.
We tried to go up to a 12" version and got to the mid 150s with it, but never really pushed hard to see what the design was capable of. I actually got off track at that point and started competing with the slot vented enclosures and straight rear loaded horns. They got big and ugly too lol.
What kind of car, woofers, amp, etc are you looking at putting together? I am sure I can offer some ideas on this one.

Robert [/quote]


Hi RObert ! ty for answer ! I didnt know that about Don i hope that everything is OK with him now ??

Regard box and car ;
car : VW POLO , car resonant freq. is 56 Hz
subs: 2 x Soundstream Tarantula T4-10
Amp: GroundZero 2.3000D

this season i comp at StreetA class, but i wonna try this box for SuperStreet 1-2 NW ....

thx !

interesting, but not what I have, so there's TWO!

I like this idea
I think you could even open the back side of the port with a small sized vent into the cavity and adjust the size of it to change the tuning?
This might be more creative than even I want to get started on lol, but it would be interesting to say the least.
The WO as is seems to have a pretty good boost around 45 hz (maybe a little lower?) which would indicate that the horn is unloading prematurely and acting closer to a standard 4th order so by porting the rear side of the driver with a tuned port, I would assume you would gain efficiency like a 6th order does, which means louder and more tuneable.
So if we make the bottom side a very long port, I wonder if it would smooth out the overall response? Might make it sound better in a HT situation?
Of course for str8 SPL I think that we would want the enclosure to be more efficient and house a higher power driver. The only problem I have run into with this is that the WO is fairly flimsy in regards to SPL because of the removable lid. It holds well, but it is a different type of constraint than the conventional vented chambers most guys are using. This is the reason we went to a bigger "ported" chamber and started making the ports expand like a horn mouth. This took away the necessity to tune the port as it unloaded at the resonant frequency on it's own. Of course we are talking about a wall and big subs in a small car lol.
I am still interested to see if the WO can be made to do more, although Don and I had this conversation for months, neither of us ever built more of them. I think it just wasn't financially viable when we were using the bigger stuff to compete.
Anyone feel like some sawdust? Have saw will travel! Heck at this point, I will come to someone's house and build it for them if they have the tools! (Oh and the materials would help lol)
Personally, I like throwing the ideas around as much as building, but it just isn't as satisfying as powering it up and listening.

Go Loud or go home!
Robert

This would be testing my knowledge of horns methinks  :-*
Just to oversimplify things let me ask a question.
Doesn't the expansion of a horn basically release the sound wave into open air at a point where the frequency's size is equal to the mouth area? Or at least in this instance 1/4 wavelength of the frequency?
If this is the case, then the longer the horn gets, the more control over the wavefront it would have therefore providing the speaker with a cushion to load against and reinforce the wave. At least that is how I see the expansion helping to make the horn more efficient than a typical box.
If anyone has a simpler explanation, that is what I want. i have read a bunch of books on the subject and had several conversations with Mr. Bruce Edgar about it, but the complications are all mathematics and little theory really.
That being said, I believe that the effect of a longer horn is a more level and smoother sounding response, but the only output gain being from the improved power handling and limited excursion created by the pressure back against the woofer at a given frequency.
Now I am getting too technical to be practical though. Any thoughts? To get more SPL basically you have to increase the power, increase the cone area, increase the excursion, or increase the efficiency of the entire system (of course any combination of the above multiplies). So, in theory this means that the most SPL producing set up would be a chamber that has an open horn on either side of the driver, but there is no way to model it that I know of. Could one say that a horn on both sides would double the output? Of course wouldn't the 2 horns be 180 degrees out of phase unless they were different lengths with different expansion ratios.
I had this conversation with Mr. Edgar and he laughed at the complexity of it at the time saying it was more trouble to do on paper than in practice and I should build it and let him know how it turned out lol.
Ahh to have my shop back. On the good side, my best friend has a saw and a shop and I have some other tools. I just need a brad nailer and a good compressor and I am on my way again.
The WO is a bass enclosure so working with more horns and more size is probably not going to affect it as much as changing the chamber size, power handling, and excursion of the drivers. Who wants to be the first to build one of these monsters we have described? Personally I am up for the port out the bottom idea with the opening on the same side as the mouth. I might build that with a really, really low tuning frq just to see if it sounds good for a TV stand in my HT. Anybody know of a 10" with a really low Fs? (Like below 20hz)
Ok enough books for today. I am getting carried away lol.

Went loud, went home!  :'(
Robert

Speaking of which?
Has anyone measured the length of the horn section of a WO?
Just wondering what the length equates to at quarter of one wavelength?
Plus this would be modeled as a front loaded and I don't really know that much about front loaded horns.
I think the WO really acts more like a typical 4th order BP than any horn just because it is so short and abrupt, but it does seem to have a little better roll off from tune than a typical BP enclosure with the right woofers in it.
Now I want a drawing of the design you have in mind there JJ420 I am interested lol.
Whose cooking up something to build next? ???

you mean for the wo32 double-thingy your talking about, stretch the horn throat all the way back to where it's almost a point, fed by the compression chambers instead of being a direct front loaded horn? Basically, keep it 6th order, but stretch the throat farther down the side wall. Would probably want to put some type of bracing in there; that a pretty good sized piece of material there for the first section of the horn.

OMG This makes me feel old!
That post is over three years old and Don is talking about the fact that the tests he and I did were "3 years ago". That means it has been 6 years since we messed with that design seriously! I had forgotten all about the "street" and "WR" spl classes lol!
If I remember correctly Don's test vehicle at the time was a van and mine was a Blazer. We tried cutting a whole bunch of slots in the box in different locations to see what would happen. We also expanded the throat opening anywhere from 3/4 inch to 3 or maybe 4 inches. The best we could get in the large vehicles was his 12" box with a slot cut right at the mouth opening if I am remembering right and this picture shows it exactly as it was built.
 

Now to the double WO box!
I love the sound of this simply because it should (In theory lol) double the efficiency of the driver by coupling twice as well. If we use the WO32 design and extend the horn length to make the taper a little more shallow, we could possibly get an 8' horn length? I think that would be right with the dimensions closer to the WO's 36" x 36". Then we would have room to adjust the compression chamber in both sides to be the same. The only thing is, the horns would be 180 degrees out of phase? I am thinking this would act like a TL enclosure perrsonally, but I am not sure since the expansion rate would be so much closer to ideal on both the front and back waves.
Which engineer in this group wants to take a stab at modeling a dual horn? Or would this be a quasi horn since we would in effect be loading two drivers into 4 throats that would load into two mouths?
Bleck! What a mess! I wonder how it would sound? I also wonder how to deal with the phasing? Is it possible that since the originatio of the wave would be out of phase and the horn mouth would be exactly 180 degrees that the output would sum slightly behind the timing? Seems like trying to time a piston engine at that point?
Let's build one! I am in!
SOmebody supply woofers and wood and I will put it together this weekend, otherwise I will build it as soon as funding permits I think. (Hey I built enough of these things, I should be able to do it in my sleep!)

Did I start this madness?

Robert

keep thinking and trim your wanter!
A nicely trimmed wanter can be a good thing, but to often they get bushy and overgrown and take over the thinking.

Man this is one crazy night for me, but a whole lot of fun.
this is what happens when the cabin boy is left on the ship alone.

LOL
thanks Robert! Last night was a creative night, not all that usefull but creative.

Hey!
I remember seeing that. Did Don ever build that one?
I can't remember. I see he is active over on the Termpro site again. I will check up with him tonight to see how his surgery went and everything. Looks like he is still kicking!
Might have to dredge up some memories from him, lol.
Now, is that supposed to be a 4 woofer set up or was that just the drawing for doing it with either set of drivers?
Seems like I remember one with the peice on the front. I can't remember what we were doing when he started that though. Might have been chambering that front wave pressure to adjust the frequency, but I am fuzzy now about why we started making that mod. Blech!
I hate getting old!

Robert

LOL oh, yes it is confusing :S i didnt noticed lower right chamber... and WTF ?? why is it closed at the front...hm ...  ??? ??? ???

looks like a ported wo to me...

ok i think im ganna make the 18" WO.....now i have to think about porting the back chamber ???...why can i just let good enuff b just that....... *light comes on* i am a bass freak....thats why

This has come up a million times. The WO is a 4th order bandpass with what is similar to a multi port front side.
If you wanted to model it, my best guess would be to model it as a 6th order and find software that lets you put multiple ports of different sizes in the front chamber and then add a port to the rear chamber. I tried several times, but could not get anything reliabole from the computer model. The best we did was experiment with a hole in the mouth of the horn and adjusting it's size. If you leave it the length of the peice of wood (3/4") the size of the hole will determine the tuning frequency, but beware the box becomes very one note oriented.
I have not tried extending the port to make it an actual tuning element, but I think it would have some effect. If it could be tuned close to the same as the mouth of the front port is at the point where it exits, the box should see a very large rise in output at that frequency.
There is a lot of math that can be thrown at this, but the only way to do it is to build first, listen second and measure third.

Shoot first, ask questions later. That's what I always say lol.

Good luck if you embark on this road. I think I posted pics of the ported WO design I have recently either here or in another WO thread. Check that out too.

Robert

the spl idea is catching me. over here,  street a is dominated by a guy who runs 2 dd 10's and a dd z1 hitting something like 142.x beating him with a bit less power is my objective.
so my guess is that a ported wo would be fun to try.
an imperial is on next summer's 'to do list', so the wo will have to wait a little.

[quote author=Adrian D.  link=1157009897/30#35 date=1161170682]the spl idea is catching me. over here,  street a is dominated by a guy who runs 2 dd 10's and a dd z1 hitting something like 142.x beating him with a bit less power is my objective.
so my guess is that a ported wo would be fun to try.
an imperial is on next summer's 'to do list', so the wo will have to wait a little. [/quote]


lol, 142 ?? in truck or ? thats nothing for z1 and 2 x 10" ....

as soon as we finish the WO to plan, we'll test and get a baseline (or should it be bassline?)  then we will play with different aeroports, starting small and short -  it may be a little while before I can post results, as we are starting remote start season here!

are you going to port out the sealed chamber at a 90?  Have to let us know how it does....

[quote author=J_Rock  link=1157009897/30#40 date=1161192864]

Why is this here? and why is it funny? If the mic is a new termlab that is pretty much the max those inefficient subs will do...

[/quote]

because, with Z1 and 2x10" DD subs  in Skoda hachback, i guess it is Fabia, it must go around 150 dB ... my friend with 2x 150W subs and 400W amp , in seald enclosure doing that score (142 dB ) ,in closed trunk car @ peak 49Hz .......

e

J_Rock wrote on 10/18/06 at 18:34:24:


Actually Rich from Realm of Excursion hit 149.5db on the new termlab with two DD 10s

DD subs are pretty potent in the correct enclosure