Shouldn't it be possible to use a filter (probably digital) that clamps response increasingly with each cycle, up to a certain point? That is, a resonant filter that reaches its steady-state at the same point in time as the wave cannon, and has a cut that matches the boost from the cannon? If you throw in a limiter, one would think the home theatre performance would be pretty amazing, and the transients wouldn't be that slow. Variable phase on the high-pass output would allow you to get it in tune with the satelites; phase differences between the sub and satelites would appear to be the real origin of perceptions of "fast" or "slow" bass, rather than the actual rise/fall time of the response, which is usually fast enough.
Thanks for the feedback -- and also the AMAZING wealth of information throughout this thread (and website).
DrewP:
Great job on your CANNON. I, too, agree that the design has greater sensitivity and a flatter response curve than a single pipe (although EL-PIPE-O part 9 is REALLY COOL and elegant -- see: http://www.passdiy.com/projects/el-pipe-o-9.htm).
purplepeople:
actually only the photo is huge -- the units are hidden under the bed (9" x 13.5" x 58.5" x 4 or 16.45 cu ft)
BAM: yes
Seriously though, they are much less muddy and boomy than the 4 cu ft ported boxes they were in before. I am definitely a T-LINE believer and faithful servant of David Dlugos.
angel:
You could try that BUT ... I am a big believer of "Keep It Short and Simple" (although a 1/3 octave EQ would help to tame the ROOM EFFECT (see http://www.svsubwoofers.com/ampeq_art_351.htm).
DrewP:
Great job on your CANNON. I, too, agree that the design has greater sensitivity and a flatter response curve than a single pipe (although EL-PIPE-O part 9 is REALLY COOL and elegant -- see: http://www.passdiy.com/projects/el-pipe-o-9.htm).
purplepeople:
actually only the photo is huge -- the units are hidden under the bed (9" x 13.5" x 58.5" x 4 or 16.45 cu ft)
BAM: yes
Seriously though, they are much less muddy and boomy than the 4 cu ft ported boxes they were in before. I am definitely a T-LINE believer and faithful servant of David Dlugos.
angel:
You could try that BUT ... I am a big believer of "Keep It Short and Simple" (although a 1/3 octave EQ would help to tame the ROOM EFFECT (see http://www.svsubwoofers.com/ampeq_art_351.htm).
It's great to breath some fire into this thread again!
Still a TL lover, after building OBs, I have finished, recently, a TL that takes a lot of inspiration from many sources. I havent' been able to measure what I hear however so I'll just name how I designed it quickly. Cross-sectional area=radius of driver^2. A line was then created by calculating wavelength at 34Hz. The driver was placed 1/3 from the end of of the line. This is a play on Bose's phase+velocity theory and is derived from theories on Voigt's and others etc. The ports exit on a similar baffle and from what I can tell is a fair amount of cancellation from this direction. The sound, with no stuffing is zero box resonance (pas de boomy) and tight, deep and accurate. I'll post pictures sometime, I hope, considering the top was yanked off to pull out the Alpine (crappy products) driver that blew up. Guess I'll have to find something of actual quality now *(Illusion Audio, Vifa).
Still a TL lover, after building OBs, I have finished, recently, a TL that takes a lot of inspiration from many sources. I havent' been able to measure what I hear however so I'll just name how I designed it quickly. Cross-sectional area=radius of driver^2. A line was then created by calculating wavelength at 34Hz. The driver was placed 1/3 from the end of of the line. This is a play on Bose's phase+velocity theory and is derived from theories on Voigt's and others etc. The ports exit on a similar baffle and from what I can tell is a fair amount of cancellation from this direction. The sound, with no stuffing is zero box resonance (pas de boomy) and tight, deep and accurate. I'll post pictures sometime, I hope, considering the top was yanked off to pull out the Alpine (crappy products) driver that blew up. Guess I'll have to find something of actual quality now *(Illusion Audio, Vifa).
QI,
Many thanks for the praise, I still ahven't got the thing installed in my friend's roof and my wife is beginning to get a little peeved about having a garage that looks like a missile silo.
hopefully in the next month...
At least the weather will be suitable for roof adventures then. most of the year it's too hot or too cold.
The second pipe (the one to go in MY roof) will have to wait for the moment, waaaaay too many diy projects all fighting for space.
Love the bed base... "did the earth move for you honey?"
Drew
Many thanks for the praise, I still ahven't got the thing installed in my friend's roof and my wife is beginning to get a little peeved about having a garage that looks like a missile silo.
hopefully in the next month...
At least the weather will be suitable for roof adventures then. most of the year it's too hot or too cold.
The second pipe (the one to go in MY roof) will have to wait for the moment, waaaaay too many diy projects all fighting for space.
Love the bed base... "did the earth move for you honey?"
Drew
i want one!
is it important to have the line resonance Above Fs as in regular enclosures???
edit> oh i just read-that this woofers resonance is 28hz-so probably not.
im thinking that this maybe a good idea for a crazy friend,who was wanting a 25hz basshorn-this is much more simpler and less likely to go wrong
Could 2 cheaper woofers be used isobarikly/?
Cheers!
is it important to have the line resonance Above Fs as in regular enclosures???
edit> oh i just read-that this woofers resonance is 28hz-so probably not.
im thinking that this maybe a good idea for a crazy friend,who was wanting a 25hz basshorn-this is much more simpler and less likely to go wrong
Could 2 cheaper woofers be used isobarikly/?
Cheers!
Hi Mikee,
I'm not sure that there's much point using an isobaric configuration. Better to make twin pipes and thereby lower the driver excursion for the same volume than to try to drop the Fs.
I think the air column in the tube imposes a mass load on the driver diaphragm and lowers Fs somewhat anyway but haven't done any measurements to check.
Certainly the response of twin pipes is smoother and less likely to go wrong than a 25Hz basshorn. (and my god! the size required!)
drew
Bose(o) talked about the Bose Phase+Velocity theory. What is this? Can you elaborate more on it without Bose lawyers coming and breaking our doors down, shooting our dogs, beating up our parents, smashing our computers, opening up our hard drives and smashing the platters into little pieces, and dragging us out into the street to be run over by their Lincoln Town Car several times?
A patent is public domain but commercial monopoly
Just don't make any money from it - and that's revenue w/ or w/o profit. If you make profit, you will just be more tasty to Amar's sharks.
If it is patented, then it must have been published and we can discuss with impunity. As long as it remains only as conversation....
ensen.
Just don't make any money from it - and that's revenue w/ or w/o profit. If you make profit, you will just be more tasty to Amar's sharks.
If it is patented, then it must have been published and we can discuss with impunity. As long as it remains only as conversation....
ensen.
When I was thinking about the folding (post #11) I first arrived at the construction qi uses.
Then I thought it would be nice to use the deflector panels as smooth tube ends, giving less turbulence. I don't know how much it will differ sound-wise but it would definitely give some distinction to the B%&e drawings.
I know it will be a little more difficult to build and will have less mechanical stability (if you want to put something onto it) OTOH.
Regards
Charles
Then I thought it would be nice to use the deflector panels as smooth tube ends, giving less turbulence. I don't know how much it will differ sound-wise but it would definitely give some distinction to the B%&e drawings.
I know it will be a little more difficult to build and will have less mechanical stability (if you want to put something onto it) OTOH.
Regards
Charles
Drewp:
yes it wil be about 2000L-ive forgotn now.
i really only want to design it-and leave it to him to put together hahaah
i think that this pipe would give him the low end he wants without horn complexity!!
i think hes drunkn and smoked abit too much of the proverbial ..
but 25hz... haha GO the sinewaves@! and the behringer ultra [bass pro sub harmonic processor.
i may build a cannon myself for shts and giggles
i want to see an SPL curve in room and to know how efficient too wud be great.
edit-
Can i use two woofers beside each other? i have two spare philips 12" woofers i want to use (48hz fs) a bass cannon bed sounds good it still works doesnt it,as pressure doesnt change much from the end..if i remember my old tline theory right
hold on,is it high velocity at end,high P at throat..argh
does anyone have a horn folding script? i hate spending 2hrs folding horns in CAD including wood thicknesses
yes it wil be about 2000L-ive forgotn now.
i really only want to design it-and leave it to him to put together hahaah
i think that this pipe would give him the low end he wants without horn complexity!!
i think hes drunkn and smoked abit too much of the proverbial ..
but 25hz... haha GO the sinewaves@! and the behringer ultra [bass pro sub harmonic processor.
i may build a cannon myself for shts and giggles
i want to see an SPL curve in room
and to know how efficient too wud be great.edit-
Can i use two woofers beside each other? i have two spare philips 12" woofers i want to use (48hz fs) a bass cannon bed sounds good it still works doesnt it,as pressure doesnt change much from the end..if i remember my old tline theory right
hold on,is it high velocity at end,high P at throat..argh
does anyone have a horn folding script? i hate spending 2hrs folding horns in CAD including wood thicknesses
Attachments
As an example, the actual Bose Cannon's long end is 9 feet. That is a 1/4 wave length tuning of 31hz.
The Bose patent suggests a driver "MAY" have a free air resonance (Fs) as high as 62hz for this configuration (IMO this is the UPPER MAXIMUM -- but this is my interpretation only).
The Bose Acoustic Wave System's long pipe is 54", a 1/4 wave tuning of 60hz, allowing a driver Fs of up to 120hz, Bose uses the 4.5" driver from the 802 system. I haver not seen numbers on thid driver.
I, and others, are still hoping a generous soul will run these numbers through SoundEasy/BoxCAD (which allegedly models the Cannon) for further confirmation of these patent interpretations.
Take a look at the following driver. It may be a good choice...
http://www.adireaudio.com/diy_audio/drivers/adire/dpl12.htm
Regards
Joe
Here's detail on Tom Danley's KICKASS LABhorn...
http://www.prosoundweb.com/lsp/labhorn1a.jpeg
Here are some drivers for it (u need two)...
http://www.adireaudio.com/diy_audio...adire/dpl12.htm
Here's a way to corner load ANY sub for more bottom end
(see chart #2, not #1)...
http://ldsg.snippets.org/HORNS/basshornfea.html
Cheerio
Joe
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