Been rounding up 6th order bandpass, about my design i have question
front port is larger than front chamber, is this going to act like front loaded vented horn or 6th order bandpass, hornresp shows some difference between these two, not much but visible to my eyes.
6th order bandpass is bit mindblow, it´s just group delay controlled vented box
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I doubt this will work well.
For the 6th order to sound good, the front chamber port length should not exceed like 3 inches to maintain reasonable sq. The shorter the better. Of course port area needs to be as big as possible.
Also the rear chamber port is very (too) long.
I try to stay below 8 inches port length on the rear port for sq reasons.
For the 6th order to sound good, the front chamber port length should not exceed like 3 inches to maintain reasonable sq. The shorter the better. Of course port area needs to be as big as possible.
Also the rear chamber port is very (too) long.
I try to stay below 8 inches port length on the rear port for sq reasons.
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different between simulations
i could make ports smaller and shorter, it would be very light use
yea i believe 90deg in port builds up some sort of acoustic cut the way any sim software would not understand
that cut at 150hz is from rear vent
best truth is build it and listen to it
The air column in the resonator must be excited. The longer the resonator the more delay which equals less precision.
I agree.
I had to build numerous enclosures of 6th orders until I was satisfied with fr and sq.
For max spl a good base is a almost flat fr and bandwidth of around 1 to 1.5 octaves.
For sq I would tune the rear chamber below 30 hz (around 28 hz, port length no longer than 10 inch) and the front chamber to maybe 120-150 hz (or a little more) for it to be outside of the intended freq range because of group delay.
You will still have the low freq boost.
Active filtering will take care of the upper peak.
Front port length like 1 inch or a little less.
Front port area at least 2/3 Sd.
Rear port area at least 1/3 Sd.
This is how they sounded best.
this type is easier to make way i want it to be, i really want to keep driver that way so no straight force sagging suspension.
"Front port length like 1 inch or a little less.
Front port area at least 2/3 Sd.
Rear port area at least 1/3 Sd."
bit hard, driver is 18"
Depends on driver parameters.
Low vas will help.
A good sounding 6th order bp will always be big but also it will sound big, sometimes bigger than it is.
A good sounding 18 inch will be huge, even with a low vas driver.
I forgot above^^ to mention I always made the front chamber like 1/2 of driver vas.
Low vas will help.
A good sounding 6th order bp will always be big but also it will sound big, sometimes bigger than it is.
A good sounding 18 inch will be huge, even with a low vas driver.
I forgot above^^ to mention I always made the front chamber like 1/2 of driver vas.
^^qts of 0.34 is good enough for a 6th order.
But with 19 mm xmax port area is important.
There is also a 18 inch X1 bandpass sub.
Speakerplans.com
Maybe good for inspiration.
Or just sim the enclosure maybe it will fit or you just need to modify it a little.
But with 19 mm xmax port area is important.
There is also a 18 inch X1 bandpass sub.
Speakerplans.com
Maybe good for inspiration.
Or just sim the enclosure maybe it will fit or you just need to modify it a little.
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difference on sims at 50volts, vituixcad keeps output same, hornresp shows difference if port lenght and area doubles, more low end
port velocity 15m/s vs 9m/s at 20hz
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Last summer, I got one 2x18" 6th for very low price but it was equipped with cheap drivers not working properly at all. However, I installed RCF LF18x400 drivers I had laying around and that made huge difference. This sub is VERY loud down to 30Hz and even lower. Well, kind of slowish which is typical for bandpass but anyway surprisingly loud even tho there might be even better driver options (I heard a rumour that original drivers were JBL 2241's).
Anyway, the box is series tuned, has 2 back chambers (one for each driver). About 100 litres, tuned to around 30Hz. Front chamber is 150-200litres and tuned 60Hz (note: i have NOT measured exact chamber volumes).
Bad sound quality video, but I hope it gives something about the SPL at lower notes. The whole brick building was shaking.
YouTube
Anyway, the box is series tuned, has 2 back chambers (one for each driver). About 100 litres, tuned to around 30Hz. Front chamber is 150-200litres and tuned 60Hz (note: i have NOT measured exact chamber volumes).
Bad sound quality video, but I hope it gives something about the SPL at lower notes. The whole brick building was shaking.
YouTube
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that video made my day.
about bass slowness is it still slow bass after correct dsp delay
big vented is in its range 1-18ms group delay
compact 6th 4-10ms group delay.
i could be turning this on my head my own way.
ok 10db eq does its own thing to gd
about bass slowness is it still slow bass after correct dsp delay
big vented is in its range 1-18ms group delay
compact 6th 4-10ms group delay.
i could be turning this on my head my own way.
ok 10db eq does its own thing to gd
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http://www.kling-freitag.de/content/uploads/ds_access-b5_de.pdf
im shocked this design acting as 6th order bandbass.
gonna give a try and build as i had mind on first, yesterday i did little bit different plans but gonna ditch them.
im shocked this design acting as 6th order bandbass.
gonna give a try and build as i had mind on first, yesterday i did little bit different plans but gonna ditch them.
I have two of those, almost identical design. 2x15". Drivers are RCF L15P540, and does no work too well.. maybe i should give it another change with better drivers someday.
It's so called "manifold" design they said.. kind of 6th order bandpass anyway because the front chamber indeed has it's own resonance frequency.
I´ve heard K&F PA on some events, allways loud and hard hitting bass.
i chosed only 15mm ply cause these are going to home audio use.
we´ll see is it acting as 6th or front loaded horn and was globalplayer right about desing not working.
im gonna flood this thread with measurements
i chosed only 15mm ply cause these are going to home audio use.
we´ll see is it acting as 6th or front loaded horn and was globalplayer right about desing not working.
im gonna flood this thread with measurements
Well, my 2x15 subs are not too loud because drivers start "flapping/farting" around 300Watts input.. or as soon as cone movement is close to xmax something like that.
Not sure if it its just bad drivers for this design or too much stress/pressure for cones.. who knows. Well, according to specs RCF L15P540 is more like midbass/midrange driver but I have been told it should work well with great authority down to 40Hz in proper BR enclosure.
I can take some measurements from these enclosures.
I wouldn't call these as front loaded horn.. where is the long horn required for bass frequencies? There is no such a thing, just somekind of chamber having one end open making it kind of 6th bandpass.
Not sure if it its just bad drivers for this design or too much stress/pressure for cones.. who knows. Well, according to specs RCF L15P540 is more like midbass/midrange driver but I have been told it should work well with great authority down to 40Hz in proper BR enclosure.
I can take some measurements from these enclosures.
I wouldn't call these as front loaded horn.. where is the long horn required for bass frequencies? There is no such a thing, just somekind of chamber having one end open making it kind of 6th bandpass.
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or its just short horn, but simmed with hornresp result is near the same.
http://www.eighteensound.com/Portal...8 kit_rev060315.pdf?ver=2015-03-09-165227-100
like this, i think real 6th cuts high frequency more than front horn, at least if there´s damping material on the box.
this was my front horn sim on post #3
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