Bandpass designs |
Post Reply | Page 123 4> |
Author | ||||
Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
Post Options
Thanks(0)
Posted: 28 March 2008 at 11:09am |
|||
Could someone clear this up for me please....?
As far as i know....
4th order bandpass looks like this:
6th order looks like this:
8th order looks like this:....?
Assuming i got those right....
WHATS THIS!?
Is it a form of 6th order bandpass?
|
||||
Disco Stu
Old Croc Joined: 03 March 2005 Location: United Kingdom Status: Offline Points: 2487 |
Post Options
Thanks(0)
|
|||
Presumably 7th order
|
||||
All you need to know is:
Sensitivity + Power Handling - Power Compression = Max Output My acts: www.myspace.com/thebowiexperience www.myspace.com/scheisseelektronisches |
||||
Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
Post Options
Thanks(0)
|
|||
Hmm, do you know of any others? I have heard of 5th order mentioned somewhere before. Is there any reason they're called 4th, 6th ect so i logically work it out?
|
||||
Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
Post Options
Thanks(0)
|
|||
I keep thinking its 5th order, but then logically this one would be 7th order not 8th....
|
||||
ceharden
The 10,000 Points Club Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11776 |
Post Options
Thanks(0)
|
|||
It's all related to the number of poles AFAIK it has cos what you're actually doing is applying acoustic filters. I really should know the answer to this.
|
||||
Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
Post Options
Thanks(0)
|
|||
Its weird cos i keep searching the net for the answer, all i want to see a list of pics like mine saying 4th, 5th, 6th, etc. so that i can understand it. but i cant find the info anywhere.
|
||||
jsg mashed
Registered User Joined: 18 May 2007 Location: United Kingdom Status: Offline Points: 305 |
Post Options
Thanks(0)
|
|||
Your question has awoken the god of bandpass... which is me!
Yup.
Correct. This is one kind of 6th order bandpass, commonly known as Parallel tuned, P6 or type A.
You are indeed correct. One could conceive of other 8th order topologies, but this is the only one I've seen used.
This would be 6th order. It will have the interesting property of rolling off at 24dB/octave at the top end and only 12dB/octave at the bottom end. The usual 6th order designs, like the one you sketched above, are the other way around.
Personally I prefer the rear chamber ported for excursion control and extended LF response, but others would disagree including the designer of the Function One speakers.
As regards calculating the order, basically you get 2nd order for the driver and 2 more orders for each chamber/port pair you add on. Odd orders can be made acoustically, but most commonly they result from adding series inductors/capacitors to the driver. Here, basically each component adds 1 order.
Note that this is a very rough guide. Some cabinet types don't really have an order, since their transfer function is not of the right type to apply an order to. Sometimes you can have two chamber/port pairs that are identical and driven in parallel so they act as one (eg JBL's TCB). Taking into account cabinet wall flexing and airload charateristics change things and that's before you get into non-linearity.
|
||||
...because Good is Dumb.
|
||||
Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
Post Options
Thanks(0)
|
|||
Aha just the man, i thought you might respond! The only reason i know what an 8th order looks like is because of your design (i wont mention the name or people may start attacking each other!)
Are there any other common bandpass arangments that you have come accross that i havent listed? i'd like to compile a comprehensive list on here for referance.
cheers
|
||||
jsg mashed
Registered User Joined: 18 May 2007 Location: United Kingdom Status: Offline Points: 305 |
Post Options
Thanks(0)
|
|||
There's the series 6th order (S6 or type B edit: also cascade 6th). You take the 4th order and add an internal port parallel to the driver. So it looks like a reflex enclosure with both port and driver going into a final resonator.
Edited by jsg mashed - 28 March 2008 at 3:48pm |
||||
...because Good is Dumb.
|
||||
Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
Post Options
Thanks(0)
|
|||
Series 6th:
|
||||
Jake_Fielder
Old Croc Joined: 08 October 2007 Status: Offline Points: 4231 |
Post Options
Thanks(0)
|
|||
would these monstrositys have a name?
Would there ever be any use for these last two setups?
|
||||
jsg mashed
Registered User Joined: 18 May 2007 Location: United Kingdom Status: Offline Points: 305 |
Post Options
Thanks(0)
|
|||
[re: series 6th]
That's the one. It's good for getting low frequency extension far below Fs at the expense of sensitivity.
Just another comment on orders - when the chamber behind the driver is sealed, it does not add another order. So the order of a sealed box "acoustic suspension" cabinet is the same as that of just the driver. This is 'cause the compliance of the air in the chamber "merges" with the compliance of the driver and becomes one element.
If you then port that chamber, you seperate the two compliances because they no longer act as one. So you get an order for the port and another for the now-seperate chamber volume.
Also, bear in mind the usual orders are given based on a highly simplified model - there's lots that gets ignored when designating them.
Edited by jsg mashed - 28 March 2008 at 4:07pm |
||||
...because Good is Dumb.
|
||||
Post Reply | Page 123 4> |
Tweet |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |