Before this gets built I wanted some advice if the design is ok im such a noob it's not funny lol
ae speakers Av12 driver
PE 500W amp
142L ported enclosure tuned to 18hz
two 4" flared ports 37.94 inches long
I plan to have a simple box design with the driver and ports on the front baffle. With the box braced heavly. I was going to buy precsion flared ports from PE and use the flared ends on some pvc pipe which will have to bend to fit inside enclosure.
If i increase enclosure to 160l the port will be 33 inches instead of over 37, better?
is this project doomed for failure or is it ok to go ahead?
stick to this or something else?
ae speakers Av12 driver
PE 500W amp
142L ported enclosure tuned to 18hz
two 4" flared ports 37.94 inches long
I plan to have a simple box design with the driver and ports on the front baffle. With the box braced heavly. I was going to buy precsion flared ports from PE and use the flared ends on some pvc pipe which will have to bend to fit inside enclosure.
If i increase enclosure to 160l the port will be 33 inches instead of over 37, better?
is this project doomed for failure or is it ok to go ahead?
stick to this or something else?
I know passive radiators are more expensive, but this box is large for an AV12.
It will work but it might be slightly boomy.
It will work but it might be slightly boomy.
it doesnt have to be that large but ports are very long no matter what size.
I would use PR but funds very tight.
what would be a good comprimise using ports?
I would use PR but funds very tight.
what would be a good comprimise using ports?
If I was to use 4cf which is 113L could I get away with one 4" flared port?
this is the design recomended so someone must of built it?
please help I have allready bought the av12
this is the design recomended so someone must of built it?
please help I have allready bought the av12
A four inch port with Precision port flares each end (30mm radius) is good for 17 - 18 m/sec. before you get audible chuffing.
Use a design program that lets you check peak port velocity (for example WinISD). If the velocity is higher than this, you'll need to reconsider. A single 4 inch port is usually what you use for a 10 inch driver. I suspect that you will need a pair
regards
Collo
Use a design program that lets you check peak port velocity (for example WinISD). If the velocity is higher than this, you'll need to reconsider. A single 4 inch port is usually what you use for a 10 inch driver. I suspect that you will need a pair
regards
Collo
Ok been playing about in winisd how does this sound?
av12 with 250w
104L enclosure tuned to 18hz with one 4" flared port which gives port velocity under 35m/sec
Im happy with this but will 250w be ok?
av12 with 250w
104L enclosure tuned to 18hz with one 4" flared port which gives port velocity under 35m/sec
Im happy with this but will 250w be ok?
Are you using WinISD or WinISD Pro? The help file in the first one recommends a max speed of 34 m/s. The pro version (still free) has better graphs and has dropped the recommended speed to 17 m/sec.
I'm using the pro version and its database comes with a driver named "Stryke Audio SAE1204". I'm not sure if this is the same driver - if not, maybe you could attach your project file and we can have a play around with it.
On the off chance that the driver is correct, I ran your figures and found:
- Peak velocity is 33m/sec at about 16hz. This falls below 17 m/sec once frequency is above about 23hz. What you are banking on is that there will be be very little full power content below 23hz. This is probably a reasonable assumption.
- Cone excursion fine above 16hz - again reasonable.
- Pipe mode resonance - around 270hz - OK with the low-pass that the PE amps have.
I'm using the pro version and its database comes with a driver named "Stryke Audio SAE1204". I'm not sure if this is the same driver - if not, maybe you could attach your project file and we can have a play around with it.
On the off chance that the driver is correct, I ran your figures and found:
- Peak velocity is 33m/sec at about 16hz. This falls below 17 m/sec once frequency is above about 23hz. What you are banking on is that there will be be very little full power content below 23hz. This is probably a reasonable assumption.
- Cone excursion fine above 16hz - again reasonable.
- Pipe mode resonance - around 270hz - OK with the low-pass that the PE amps have.
I have read 34-35m/sec alot of places im using winisd pro.
I would think it is impossible to get under 17m/sec with av12 and 250w no matter what i do it doesnt go anywere near that low, not without insane port lengh
I would think it is impossible to get under 17m/sec with av12 and 250w no matter what i do it doesnt go anywere near that low, not without insane port lengh
If i was to use this port
http://www.nexxia.co.uk/Hi-Fi&TVaccessories/speaker_port_tubes.htm
which says 115mm Inner diameter (4.5inch) that would give me 27m/sec at 15hz
and only 33 inches long which isnt much in a bend
http://www.nexxia.co.uk/Hi-Fi&TVaccessories/speaker_port_tubes.htm
which says 115mm Inner diameter (4.5inch) that would give me 27m/sec at 15hz
and only 33 inches long which isnt much in a bend
That extra diameter looked good but checking the link and the photos, I see that it isn't flared - its performance would be worse than a 100mm port with 30mm radius flares.
I've been playing with the project file you posted and it does seem like quite a challenge with that driver. The T/S paramaters are quite different to the one I analised earlier so forget those results.
Using a similar approach though, gives three possibilities for a vented box...
Your single 4in port will exceed 18 m/sec for full power content below about 23hz. DVD content at 23hz is generally not at full power, but occasionally it could be.
If you go to a pair of 4in flared ports, your velocity worries are over, but the extra length gives you a pipe mode resonance at 125hz - typically a peak of around 6dB. This would mean you should cross over to the sub at the lowest frequency offered by your system, provided your mains are adequate.
Moving up to a 5cu ft box volume (140 litres) as suggested by the website allows shorter ports for a pipe resonance of around 170hz, which is easier to live with. Velocity sneaks up a little, but only below 19hz, where any content would not be at full power.
So there you have it - A small amount of occasional chuffing, a low crossover frequency, or a larger box. If none of these work, you might look at either passive radiator or sealed.
I'm not an expert on sealed, but I suspect you'll be able to use the full 500w that both the driver and the amp have available. With the lower rate of rolloff, you might be better off....
One thing, your project file has the sensitivity at 83.88 which seems very low. Checking the page on the AE site for the AV12 driver:
http://www.aespeakers.com/drivers.php?driver_id=13
they list sensitivity at 88dB @ 2.83v
Voltage sensitivity (2.83v into 8ohms @ 1m) can be converted to Power sensitivity (1watt @ 1m) by subtracting 10*log( 8 / Re)
This give you 85dB for the two 2ohm coils in series, which improves your output a little.
regards
Collo
I've been playing with the project file you posted and it does seem like quite a challenge with that driver. The T/S paramaters are quite different to the one I analised earlier so forget those results.
Using a similar approach though, gives three possibilities for a vented box...
Your single 4in port will exceed 18 m/sec for full power content below about 23hz. DVD content at 23hz is generally not at full power, but occasionally it could be.
If you go to a pair of 4in flared ports, your velocity worries are over, but the extra length gives you a pipe mode resonance at 125hz - typically a peak of around 6dB. This would mean you should cross over to the sub at the lowest frequency offered by your system, provided your mains are adequate.
Moving up to a 5cu ft box volume (140 litres) as suggested by the website allows shorter ports for a pipe resonance of around 170hz, which is easier to live with. Velocity sneaks up a little, but only below 19hz, where any content would not be at full power.
So there you have it - A small amount of occasional chuffing, a low crossover frequency, or a larger box. If none of these work, you might look at either passive radiator or sealed.
I'm not an expert on sealed, but I suspect you'll be able to use the full 500w that both the driver and the amp have available. With the lower rate of rolloff, you might be better off....
One thing, your project file has the sensitivity at 83.88 which seems very low. Checking the page on the AE site for the AV12 driver:
http://www.aespeakers.com/drivers.php?driver_id=13
they list sensitivity at 88dB @ 2.83v
Voltage sensitivity (2.83v into 8ohms @ 1m) can be converted to Power sensitivity (1watt @ 1m) by subtracting 10*log( 8 / Re)
This give you 85dB for the two 2ohm coils in series, which improves your output a little.
regards
Collo
cheers mate I think I will go with two 4inch ports which will have to bend. I will have to draw up a box to see how well they fit.
If i go with 4cf 113L shall I keep all the design for that but make it a few litres more bigger for the volume the ports take up?
If i go with 4cf 113L shall I keep all the design for that but make it a few litres more bigger for the volume the ports take up?
To fit ports I will have to make a shape like this which will be two 90 degree bends
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Could anyone tell me if this will be a problem?
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Could anyone tell me if this will be a problem?
Three 90 degree bends here .....
http://www.users.bigpond.com/bcolliso/snorky-gal/snorky-4.htm
This might help with the box design:
http://www.users.bigpond.com/bcolliso/freesoft.htm
Here's a screenshot of how things might turn out....
http://www.users.bigpond.com/bcolliso/snorky-gal/snorky-4.htm
This might help with the box design:
http://www.users.bigpond.com/bcolliso/freesoft.htm
Here's a screenshot of how things might turn out....
Attachments
thanks for program fantstic just what i needed.
Do u know of any software so I can build box on computer to see how far ports will be from walls etc
cheers mate been great help
Do u know of any software so I can build box on computer to see how far ports will be from walls etc
cheers mate been great help
I'm glad you found it useful - I wouldn't build a box without it.
As for working out how to fit the ports in, you should first see what 90 degree elbows are available. ( Take a tape measure and notepad to the hardware store or plumbers supplier). Only then will you be able to juggle your box dimensions.
If you are lucky enough to have a choice of brands, go for the one that has the most gentle bend. Ideally the inner radius of the bend should be no less than 20% of the pipe diameter (ie 20mm in your case), although you can't always get this. Sand off any rough edges on the inside.
Best of luck and remember to post some photos so the rest of us can enjoy it too! 😀
As for working out how to fit the ports in, you should first see what 90 degree elbows are available. ( Take a tape measure and notepad to the hardware store or plumbers supplier). Only then will you be able to juggle your box dimensions.
If you are lucky enough to have a choice of brands, go for the one that has the most gentle bend. Ideally the inner radius of the bend should be no less than 20% of the pipe diameter (ie 20mm in your case), although you can't always get this. Sand off any rough edges on the inside.
Best of luck and remember to post some photos so the rest of us can enjoy it too! 😀
Thanks The av12 will arrive monday and then I will shop around for a 250w plate amp so far I have a choice between a parts express one and a RYTHMIK one which is alot more cash.
It properly wont be fully finsihed till next month but it is photos all the way dont worry😉
It properly wont be fully finsihed till next month but it is photos all the way dont worry😉
collo get this
In winisd pro if I type in a length into vent length it allows me to have any length I want (say 17") but it moves peak velocity to a higher freqency.
exsample:
113L with three 4" ports length = 75.32. peak velocity = 12ms at 16.44hz
But if I type 17" into port length this happens
113L with three 4" ports length = 17" peak velocity = 16ms at 35.52hz
So is this correct can I choose any length I want and it just moves peak velocity up higher? can I do this?
In winisd pro if I type in a length into vent length it allows me to have any length I want (say 17") but it moves peak velocity to a higher freqency.
exsample:
113L with three 4" ports length = 75.32. peak velocity = 12ms at 16.44hz
But if I type 17" into port length this happens
113L with three 4" ports length = 17" peak velocity = 16ms at 35.52hz
So is this correct can I choose any length I want and it just moves peak velocity up higher? can I do this?
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