[cguff78]

I just finished building a ported sub enclosure for a JL 13W7 subwoofer. The enclosure measures 31.5"w x 31.5"d x 31.5"t with a 3" x 13" x 40" port (actually I think the port ended up at 3.75" x 12.25" x 40") from 3/4" MDF. It is currently being powered by a crown xs1200 amp from a single channel. I have a second driver and was going to build a second enclosure as I have another driver and run the amp in mono with the subs in series.

My question is when I ran my initial test with the new sub it seemed quieter, for lack of a better word, than my martin logan depth subwoofer. Is this because it's tuned to around 16Hz, or am I just not used to such a good sub? I did notice that the floor was shaking much more than I was used to etc, but I didn't seem to get that boomy sound like I did with my martin logan? Hope that makes sense...

 

[Bill Fitzmaurice]

I didn't seem to get that boomy sound like I did with my martin logan?

That's a good thing. Boom is sourced in the midbass, indicating a cab with too high a Q. High Q makes the cab sound louder, but it's anything but accurate and doesn't go low.
If you want higher sensitivity consider a folded horn. It would be no larger than the box size you have and would offer at least 6dB higher output.

 

[cguff78]

Yeah, that was what I was thinking, just caught me off guard a bit. I haven't watched a full movie yet, just key scenes from iron man and the die hard tunnel scene. I really noticed it in the tunnel scene how low the sub went when the car flew through the air. When I get the second one built it should help with the output and satisfy my needs.

So what is a folded horn exactly, is that a regular plastic horn that is just turned similar to me turning my slotted port along the back of hte box? Can you purchase them from parts express or somewhere similar?

 

[Bill Fitzmaurice]

So what is a folded horn exactly?

http://www.hometheatershack.com/forums/diy-speakers/11892-new-guy-system-pics.html

 

[cguff78]

http://www.hometheatershack.com/forums/diy-speakers/11892-new-guy-system-pics.html

Hmm, it appears I was way off, so it's more of a box construction shape for the sub? Guess I still don't fully understand the concept.

 

[Lonely Raven]

Here is a better example. This is my dual folded horn.

Basically it's a sub that outputs into a horn. Mine above is more of a bandpass sub box, where the slot on the front of the bandpass box actually pressurizes the horn. The horn part is exactly as you imagine.

 

[cguff78]

Here is a better example. This is my dual folded horn.

Basically it's a sub that outputs into a horn. Mine above is more of a bandpass sub box, where the slot on the front of the bandpass box actually pressurizes the horn. The horn part is exactly as you imagine.

Just noticed your using JL's as well which models did you use? Do you get better performance out of that box with both subs in one enclosure versus two enclosures? It's all very interesting, I've never heard of this design before always the bandpass, sealed, ported, passive radiator, etc.

 

[Lonely Raven]

Just noticed your using JL's as well which models did you use? Do you get better performance out of that box with both subs in one enclosure versus two enclosures? It's all very interesting, I've never heard of this design before always the bandpass, sealed, ported, passive radiator, etc.

Horns have been around forever. Hell, even old hand crank victrola's had a horn attached directly to the needle! LOL

I originally built the sub (free design at Decware.com called Wicked One) back about 8-10 years ago, and I used a pair of cheap ($80 for the pair) Rockford Fosgate 10" subs. With a 75 watt plate amp, it slammed, but didn't go deep. A few years ago my Dad, who was really impressed with the work I did, picked me up a pair of JL Audio 10w6v2 DVC drivers. I had been running them on the same 75 watt plate amp, but as you can imagine it was pretty underwhelming. I've recently purchased a EP2500 amp which drives the JL Audio properly, and I'm *really* impressed with this folded horn now!!

Basically, any movement of air can be pushed through a horn to amplify it. PA subs have been doing it for years for sheer output. Some speaker manufacturers have been doing it since the '40s or '50s with fantastic results.

The Wicked One sub that I built is basically two horns that merge into one. I've tinkered with the idea of making one isobaric (pair of 10") sub driving one, much larger horn...but never got around to it. The larger the horn, the more output you'll get out of it obviously. But from what people are telling me here in the forums, a quality 18" driver in an LLT box would do just as well for my home theater needs. So I'm probably going to ditch the dual folded horn, and just build a very large ported box in it's place.

 

[Mike P.]

That seems to be an issue for HT. Horns get loud, but not loud and low.

 

[Lonely Raven]

That seems to be an issue for HT. Horns get loud, but not loud and low.

But Mike, doesn't a horn simply amplify what's already there?

So if I had a sub that had an Fs of 15 in a sealed box, and I had it driving a nice big horn, I can't imagine how it wouldn't be loud & low.

 

[cguff78]

Horns have been around forever. Hell, even old hand crank victrola's had a horn attached directly to the needle! LOL

I originally built the sub (free design at called Wicked One) back about 8-10 years ago, and I used a pair of cheap ($80 for the pair) Rockford Fosgate 10" subs. With a 75 watt plate amp, it slammed, but didn't go deep. A few years ago my Dad, who was really impressed with the work I did, picked me up a pair of JL Audio 10w6v2 DVC drivers. I had been running them on the same 75 watt plate amp, but as you can imagine it was pretty underwhelming. I've recently purchased a EP2500 amp which drives the JL Audio properly, and I'm *really* impressed with this folded horn now!!

Basically, any movement of air can be pushed through a horn to amplify it. PA subs have been doing it for years for sheer output. Some speaker manufacturers have been doing it since the '40s or '50s with fantastic results.

The Wicked One sub that I built is basically two horns that merge into one. I've tinkered with the idea of making one isobaric (pair of 10") sub driving one, much larger horn...but never got around to it. The larger the horn, the more output you'll get out of it obviously. But from what people are telling me here in the forums, a quality 18" driver in an LLT box would do just as well for my home theater needs. So I'm probably going to ditch the dual folded horn, and just build a very large ported box in it's place.

Very interesting I may have to do some research, I have the second sub sitting awaiting an enclosure and thought I might try 2 or 3 different enclosures to see which I liked best. The one I have now is probably fine, I just don't know what good bass sounds like and if I get the second one built and put in a similar box it's just going to up the output and hopefully be even more impressive. With each sub getting somewhere around 1200W I have plenty of power to push 2-JLW13's.

 

[Lonely Raven]

I'll trade you my two 10w6 for your w13! LOL

 

[cguff78]

I'll trade you my two 10w6 for your w13! LOL

As tempting as that is I think I may just have to pass and stick with my dual 13w7 setup for the time being. That is assuming I can find the time to build a second box. Always loved JL subs, and i've been wanting to get the new Fathom's, but couldn't pass up the opportunity to try building two of my own for half the price.

 

[Bill Fitzmaurice]

That seems to be an issue for HT. Horns get loud, but not loud and low.

The Decware won't go low, but that's because the horn is less than half the length required, so it's really a midbass horn. When you use a horn path of better than twelve feet there's no lack of lows. BTW, Shawn's T36s are PA subs which are not intended for HT use, though they still do pretty well. Folded horns intended for HT use do considerably better below 35 Hz.