I'm humm-ing and haa-ing about building a 6th order sub box but I'm worried it might be a flop because I have heard people say that they are difficult to get going properly. If you have ever built one, would you like to tell of your experience with it? Did it live up to expectations? Was it difficult to tune properly? Did the software do an accurate job of predicting the box and port stuff? What does it sound like? Is there any truth in the saying that they have poor transient response? Did it really shake the place? I'm all ears.
Some Facts
The So called 6th order enclosure is some what very easy to build but not with softwares but with ears
I have build this one 2 yrs ago to ramshack the windows of my drawing room which was powered by 1KW amp
The response was 10Hz to 100Hz
The Port tuning was 20Hz & 80Hz
If u wanna build this than contact me for greates details
The So called 6th order enclosure is some what very easy to build but not with softwares but with ears
I have build this one 2 yrs ago to ramshack the windows of my drawing room which was powered by 1KW amp
The response was 10Hz to 100Hz
The Port tuning was 20Hz & 80Hz
If u wanna build this than contact me for greates details
normally a ported box 4th order will do,
i dont see why tuning would be a problem
To me it seems,the more gradual the roll off,the better the transient response
Dipoles sound good,sealed almost, ported worse, increasing order=worse still....pick ur poison
extension vs quality
i dont see why tuning would be a problem
To me it seems,the more gradual the roll off,the better the transient response
Dipoles sound good,sealed almost, ported worse, increasing order=worse still....pick ur poison
extension vs quality
Assuming that you mean 6th order reflex rather than bandpass box.
I built a 6th order sub from plans in Aug '83 Audio mag using a JBL 2245H in '84. I love it, replaced the surround 5 years ago, still haven't heard anything I like enough to consider replacing it. If I can get hold of another driver, I'll build another one. It is 8.5ft^3, tuned to 24 Hz, Q=2 HP @ 24 Hz, 60 Hz 12db/octave Low pass. I modeled it with Boxplot, and that seems to match actual response. In a 15' x 22' room it seems flat down to 20 hz or so, applying published corrections to my Radio Shack SPL meter.
Caveat: high power handling, high Xmax and tons of power are are required. With 250 watts, it runs out of steam at slightly louder than normal levels. A bridged Leach amp (60 Volt rails) is acceptable, but it really prefers my bridged Hafler DH-500 for home theater. I replaced the worn out original fan, but need to find a quieter one for the Hafler to live in the living room. Works great in my bass rig, though 🙂
I built a 6th order sub from plans in Aug '83 Audio mag using a JBL 2245H in '84. I love it, replaced the surround 5 years ago, still haven't heard anything I like enough to consider replacing it. If I can get hold of another driver, I'll build another one. It is 8.5ft^3, tuned to 24 Hz, Q=2 HP @ 24 Hz, 60 Hz 12db/octave Low pass. I modeled it with Boxplot, and that seems to match actual response. In a 15' x 22' room it seems flat down to 20 hz or so, applying published corrections to my Radio Shack SPL meter.
Caveat: high power handling, high Xmax and tons of power are are required. With 250 watts, it runs out of steam at slightly louder than normal levels. A bridged Leach amp (60 Volt rails) is acceptable, but it really prefers my bridged Hafler DH-500 for home theater. I replaced the worn out original fan, but need to find a quieter one for the Hafler to live in the living room. Works great in my bass rig, though 🙂
BobEllis do you mind giving me more info on the enclosure you designed, i have 2 of those woofers and have been deliberating on what to do with them. I've only ever heard of a 6th order bandpass.
Amoeba86, You are a lucky stiff - I really wish I had another driver, just to go stereo sub. There is plenty of output for reasonably large rooms. When I first built it, my living room had a cathedral ceiling and an open loft on the second floor, and a full width opening to the dining room. Gave me a room roughly 25x 40x 17, and I didn't run out of bass.
I didn't design the enclosure, I just built it per the article I mentioned. I pulled it out and I mis-spoke - they call the alignment quasi-fifth order. Think of cascading filter sections. A vented box is a fourth order filter, add EQ in the form of a high Q first order high pass filter and you have a 5th order filter/ alignment.
Internal dimensions from the article: 23.5 x 32 x 19, port is 12" long, 5.25" square or 5.675 diameter. This should tune the 8 cubic foot enclosure to 26 hz. Adjust proportions to suit, and brace well .
The crossover should provide 6 db of boost at 24 Hz. I bought the JBL BX63 crossover, because I didn't have the knowledge to build a crossover myself back in 1984. Grey has provided some very useful information in the Zenover thread. Fred D. also has started an active crossover thread with good info. All this talk got me going - I prototyped a LR crossover with baffle step compensation and tweeter phase correction for my focal TL's. My initial impression was very positive, But that's another thread once I have made some measurements and tweaked.
Don Lancaster's Active Filter Cookbook is also a good reference. Simply make a second order high pass filter with an Fc of 24 hz and a Q of 2 for your EQ.
An alternative that the article mentioned is to increase the volume to 12 cubic feet (44 x 29 x 21") Tune it to 25 Hz with a 9" x 20" port and you've got a 25 Hz sub with no EQ. Or increase the port length to 30: to tune it to 20 Hz, add 6 db of boost with a Q=2 HP filter and you have an F3 of 20 Hz. I suppose a bandpass filter with Q=2 and 6db of boost would work, too.
I also remember an article somewhere describing a system using 8 2245Hs in an IB array, it got down to somewhere around 10 Hz with several kilowatts and EQ . (Funny, as I write this I am listening to Jimmy Buffett's "Overkill")
Observations: The BX63 crossover has an adjustable cutoff frequency, from 63 to 125 Hz at 12 db/octave. With the croossover frequency set at anything over 70, I find that the bass comes from the sub if it is not centered. If the crossover is set below 70 hz I cannot locate the sub. My Yamaha DSP-A1 has a 24 db/octave crossover fixed at 90 hz. With that I can barely locate the sub if I try. I'd recommend a 24 db/ octave cutoff as low as possible consistent with your mains' low end if you use a single sub. Two 8 or 12 cubic foot subs has a SAF approaching 0. Even one is pretty tough to sell.
I didn't design the enclosure, I just built it per the article I mentioned. I pulled it out and I mis-spoke - they call the alignment quasi-fifth order. Think of cascading filter sections. A vented box is a fourth order filter, add EQ in the form of a high Q first order high pass filter and you have a 5th order filter/ alignment.
Internal dimensions from the article: 23.5 x 32 x 19, port is 12" long, 5.25" square or 5.675 diameter. This should tune the 8 cubic foot enclosure to 26 hz. Adjust proportions to suit, and brace well .
The crossover should provide 6 db of boost at 24 Hz. I bought the JBL BX63 crossover, because I didn't have the knowledge to build a crossover myself back in 1984. Grey has provided some very useful information in the Zenover thread. Fred D. also has started an active crossover thread with good info. All this talk got me going - I prototyped a LR crossover with baffle step compensation and tweeter phase correction for my focal TL's. My initial impression was very positive, But that's another thread once I have made some measurements and tweaked.
Don Lancaster's Active Filter Cookbook is also a good reference. Simply make a second order high pass filter with an Fc of 24 hz and a Q of 2 for your EQ.
An alternative that the article mentioned is to increase the volume to 12 cubic feet (44 x 29 x 21") Tune it to 25 Hz with a 9" x 20" port and you've got a 25 Hz sub with no EQ. Or increase the port length to 30: to tune it to 20 Hz, add 6 db of boost with a Q=2 HP filter and you have an F3 of 20 Hz. I suppose a bandpass filter with Q=2 and 6db of boost would work, too.
I also remember an article somewhere describing a system using 8 2245Hs in an IB array, it got down to somewhere around 10 Hz with several kilowatts and EQ . (Funny, as I write this I am listening to Jimmy Buffett's "Overkill")
Observations: The BX63 crossover has an adjustable cutoff frequency, from 63 to 125 Hz at 12 db/octave. With the croossover frequency set at anything over 70, I find that the bass comes from the sub if it is not centered. If the crossover is set below 70 hz I cannot locate the sub. My Yamaha DSP-A1 has a 24 db/octave crossover fixed at 90 hz. With that I can barely locate the sub if I try. I'd recommend a 24 db/ octave cutoff as low as possible consistent with your mains' low end if you use a single sub. Two 8 or 12 cubic foot subs has a SAF approaching 0. Even one is pretty tough to sell.
6th order bass alignments have a bad name because the early
adopters used maximally flat alignments that didn't take room
gain into account and basically did not suit most rooms.
B&W's website has some good information.
basically the 4th order response has to be overdamped, they
use a Bessell alignment which is a good choice - in smaller
rooms its often fine on its own.
I seriously reccommended making the Q of the final 2nd order
high pass adjustable - you can then tune it to your room.
Good results are almost guaranteed.
🙂 /sreten.
adopters used maximally flat alignments that didn't take room
gain into account and basically did not suit most rooms.
B&W's website has some good information.
basically the 4th order response has to be overdamped, they
use a Bessell alignment which is a good choice - in smaller
rooms its often fine on its own.
I seriously reccommended making the Q of the final 2nd order
high pass adjustable - you can then tune it to your room.
Good results are almost guaranteed.
🙂 /sreten.
The fixed Q (boost) explains why I liked the sound best in the biggest rooms - in smaller rooms it can be boomy. Variable Q crossover is in the works. And it won't be based on a TL084, like the BX63.
No, sorry. I mean a badass bandpass 😉 as per the picture.BobEllis said:
I didn't know there was such a thing as a 6th order reflex.
I am shooting for -1dB at 20Hz and 60Hz. Power ~50W. Efficiency - reasonably high, with the emphasis on wood being cheaper than a fancy driver.
Attachments
If you got a 6th order bandpass right it would have very
high SPL capability given the drivers excursion capability.
Pretty useful in PA applications.
A maximally flat alignment for 20Hz and 60Hz will have
utterly hideous transient response. With the two points
so close together lower Q alignments will be difficult.
Personally for hi-fi use I wouldn't go near a bandpass of
any sort - very difficult to integrate with the main speakers.
If an adjustable electrical low pass is also used to allow
integration with the main speakers then the low pass
section of the bandpass becomes fairly pointless.
Much better to use the total volume for the high pass
section, i.e. a standard relflex arrangement.
🙂 /sreten.
high SPL capability given the drivers excursion capability.
Pretty useful in PA applications.
A maximally flat alignment for 20Hz and 60Hz will have
utterly hideous transient response. With the two points
so close together lower Q alignments will be difficult.
Personally for hi-fi use I wouldn't go near a bandpass of
any sort - very difficult to integrate with the main speakers.
If an adjustable electrical low pass is also used to allow
integration with the main speakers then the low pass
section of the bandpass becomes fairly pointless.
Much better to use the total volume for the high pass
section, i.e. a standard relflex arrangement.
🙂 /sreten.
BobEllis said:Two 8 or 12 cubic foot subs has a SAF approaching 0. Even one is pretty tough to sell.
haha i'm more worried about the PAF (parental acceptance factor), i'm only 17 so I don't have a spouse to worry about 😀.
I wondering if anyone had any more info on 6th order enclosures, from BobEllis's posts i think i understand but i'd like to have a read at something more detailed. so basically it's like a vented enclosure with EQ?
amoeba86 said:
That's about it. You tune the box lower than you normally would, so that it has a drooping response below the upper resonance, then apply boost to make up the difference. Make the boost/Q adjustable to get flat in room response, as Sreten pointed out.
Boxplot is one program that allows modeling a 6th order alignment - even in the freebie demo version. You can slide the damping (1/Q) up and down to see what varying the boost does.
Bad Boys
Important: Bose Corporation of Framingham, Massachusetts, U.S.A., owns a patent (U.S. Patent 4,549,631 issued 29-Oct-85) that covers band-pass enclosures which couple both sides of the enclosure to the outside (like many 6th-order band-pass enclosures). Construction of these enclosures may infringe their patent rights.
You boy's wouldnt be breakn' the law now would Ya🙄
I pasted the above from a JBL SpeakerShop program I have.
Doug
Important: Bose Corporation of Framingham, Massachusetts, U.S.A., owns a patent (U.S. Patent 4,549,631 issued 29-Oct-85) that covers band-pass enclosures which couple both sides of the enclosure to the outside (like many 6th-order band-pass enclosures). Construction of these enclosures may infringe their patent rights.
You boy's wouldnt be breakn' the law now would Ya🙄
I pasted the above from a JBL SpeakerShop program I have.
Doug
BobEllis said:
Just add to this particular attention has to paid to excursion
limitations, it is the port that is tuned lower than normal and
the boost centre frequency is centred on the port frequency.
Note there is a class of fifth order alignments that use an
underdamped reflex alignment in combination with a 1st
order high pass filter - my opinion of these is not polite !
🙂 /sreten.
circlotron. isn't that an 8th order bandpass. i thought a sixth was closed box on the driver and vent on the next chamber.
BobEllis................
Since the JBL 2245H driver has been discontinued (they stopped making the E series too. What's next?), you may want to take a look at the 2242HPL driver. It's basically an 800 watt 18" vented gap cooled driver designed for cinema systems. It is the replacement driver for the JBL Cynergy systems and you can find it in many JBL cinema products. You've probably already heard it if you've been to a THX approved movie theater in the last couple years. I swept one yesterday in it's enclosure (which, by the way, was about the same size as you current enclosure) and this thing was just amazing! I didn't have a meter going, but this thing didn't seem to drop off untill the mid-20's. I was very impressed. It's a little harder to move than the 2245H, but it also handles twice the power.
Circlotron.........As for the sound of a sixth order bandpass, have you ever head a Bose Acoustamass system? (The one with the little cubes and no midrange) The low frequencies are produced by a 6th order bandpass box. Some people seem to like the sound, but it's not my favorite. The bass is really loose, and drops off very sharply below cut-off. If you are looking for a small sub for computer or multimedia use, they are just fine. If you are looking for audio quality, I would look somehere else.
How do you always manage to get these boards going with so much discussion Circlotron? I'm truly impressed. You seem to hve a pretty firm ground on what you're doing, and you always raise very useful and interesting points to discuss. You're a credit to the forum.
Cheers,
Zach
Since the JBL 2245H driver has been discontinued (they stopped making the E series too. What's next?), you may want to take a look at the 2242HPL driver. It's basically an 800 watt 18" vented gap cooled driver designed for cinema systems. It is the replacement driver for the JBL Cynergy systems and you can find it in many JBL cinema products. You've probably already heard it if you've been to a THX approved movie theater in the last couple years. I swept one yesterday in it's enclosure (which, by the way, was about the same size as you current enclosure) and this thing was just amazing! I didn't have a meter going, but this thing didn't seem to drop off untill the mid-20's. I was very impressed. It's a little harder to move than the 2245H, but it also handles twice the power.
Circlotron.........As for the sound of a sixth order bandpass, have you ever head a Bose Acoustamass system? (The one with the little cubes and no midrange) The low frequencies are produced by a 6th order bandpass box. Some people seem to like the sound, but it's not my favorite. The bass is really loose, and drops off very sharply below cut-off. If you are looking for a small sub for computer or multimedia use, they are just fine. If you are looking for audio quality, I would look somehere else.
How do you always manage to get these boards going with so much discussion Circlotron? I'm truly impressed. You seem to hve a pretty firm ground on what you're doing, and you always raise very useful and interesting points to discuss. You're a credit to the forum.
Cheers,
Zach
I call that one a 4th order, but perhaps it's related to the American vs English definition of 1 billion. 😉Mikett said:
What I call a 6th order (bandpass) has 6 energy storage elements, 3 potential and 3 kinetic.
Potential (stationary) energy storage elements are:
Chamber 1 compressed or rarefied air
Chamber 2 compressed or rarefied air
Speaker suspension deflected (like an archer's bow ready to shoot an arrow)
Kinetic (moving) energy storage elements are:
Port 1 moving air mass
Port 2 moving air mass
Speaker cone moving mass. (the arrow) 😉
A member here, Dustin Haug, built one. I distinctly remember seeing pictures of it. I don't know if the pictures were posted here, or on a website he had at the time.
Try Emailing him, he had many picutres and extensive construction details. He seemed pretty happy with it.
Try Emailing him, he had many picutres and extensive construction details. He seemed pretty happy with it.
When someone is talking about a 6th order bandpass I think of the same thingie as Graham.
I once built two of these for small P.A. usage. The drivers I used have a very strong motor, making them unsuitable for ordinary reflex enclosures. The optimum box for them would have been a horn, which wasn't taken into consideration for size reasons.
With the bandpass box I ended up with a tuning that was at least better than a reflex one in terms of low end extension.
Due to the 6th order characteristic they have a slightly "soft" sound characteristic.
For high-end I wouldn't use the principle but for their current usage they offer a quite good size/LF-extension/SPL compromise.
Regards
Charles
I once built two of these for small P.A. usage. The drivers I used have a very strong motor, making them unsuitable for ordinary reflex enclosures. The optimum box for them would have been a horn, which wasn't taken into consideration for size reasons.
With the bandpass box I ended up with a tuning that was at least better than a reflex one in terms of low end extension.
Due to the 6th order characteristic they have a slightly "soft" sound characteristic.
For high-end I wouldn't use the principle but for their current usage they offer a quite good size/LF-extension/SPL compromise.
Regards
Charles
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