punkrokr1701 said:
A passive radiator system incorporates an active driver and a drone (inactive) cone. The purpose of a drone cone is the same as a port. It makes use of the sound from inside the cabinet. I wouldn't recommend it for PA type gear. It's main purpose seems to be to get the most low end from a small, box type enclosure.
Did you get my email? What do you think?
Well PR, You have a couple of ways to approach this. You have a great deal of study to do before you can hope to build your own 3 way multy driver cabinets. So either you can do some serious study (search for basic instruction on crossovers and multi speaker impedence issue and study for a month or so) or cookbook a less abitious project to start with.
All of the drivers I listed are nominally 8 ohms so two of each means either 16 or 4 ohm (series/parallel wiring). For simplicity sake why not start with one of each driver and a premade professional crossover. And instead of the three piezos use one of these 8 Ohm horn tweeters and then 1 each of the woofer and midrange already mentioned.
Then hook them together with a Selenium brand 3 way crossover hooking each driver to the proper filter outputs.
Make a box with an enclosed area for woofer using the specs I gave earlier for tuning. The mid and tweeter can be put together in their own compartment. the M/T compartment size is not critical because you are crossing way above Fs. I would say any convenient size greater than 0.15 ft^3.
This would give a pretty good wrecking ball system with minimal brain work. Once you build it and get it working you can experiment with port sizes and to some extent with compartment size by putting bricks inside to reduce volume.
Now you want to get some simulation software so that you can play with ideas and see how things work without making sawdust right from the start. At a minimum get Boxplot from here it is free and great for doing quick what if's. Also pick up the free version of WinISD as well.
Learn, learn, learn. This is complicated stuff and we all end up learning new stuff all our lives in this hobby. Above all it is important to get an understanding of what is going on underneath. It is so much more satisfying than just screwing together someone else's design.
mike
BTW, after being in this hobby for a while you are going to start noticing more of the subtleties of music and want to try more refined designs or simple elegant designs that bring out the inner texture of the music and the true tone quality of instruments and the human voice. The bone crushers are fun but in a few years I expect to here that you have been seen listening to a sexy female folk singer crooning through a tube amp and full range open baffle speaker system while sipping a glass of nice dry red wine. Well good luck. I am heading to the kitchen for a glass of Merlot.
All of the drivers I listed are nominally 8 ohms so two of each means either 16 or 4 ohm (series/parallel wiring). For simplicity sake why not start with one of each driver and a premade professional crossover. And instead of the three piezos use one of these 8 Ohm horn tweeters and then 1 each of the woofer and midrange already mentioned.
Then hook them together with a Selenium brand 3 way crossover hooking each driver to the proper filter outputs.
Make a box with an enclosed area for woofer using the specs I gave earlier for tuning. The mid and tweeter can be put together in their own compartment. the M/T compartment size is not critical because you are crossing way above Fs. I would say any convenient size greater than 0.15 ft^3.
This would give a pretty good wrecking ball system with minimal brain work. Once you build it and get it working you can experiment with port sizes and to some extent with compartment size by putting bricks inside to reduce volume.
Now you want to get some simulation software so that you can play with ideas and see how things work without making sawdust right from the start. At a minimum get Boxplot from here it is free and great for doing quick what if's. Also pick up the free version of WinISD as well.
Learn, learn, learn. This is complicated stuff and we all end up learning new stuff all our lives in this hobby. Above all it is important to get an understanding of what is going on underneath. It is so much more satisfying than just screwing together someone else's design.
mike
BTW, after being in this hobby for a while you are going to start noticing more of the subtleties of music and want to try more refined designs or simple elegant designs that bring out the inner texture of the music and the true tone quality of instruments and the human voice. The bone crushers are fun but in a few years I expect to here that you have been seen listening to a sexy female folk singer crooning through a tube amp and full range open baffle speaker system while sipping a glass of nice dry red wine. Well good luck. I am heading to the kitchen for a glass of Merlot.
Hi Mike,
I enjoyed reading the last paragraph of your post.
While I concur with your thoughts of refinement, may I be so bold as to suggest that some, myself included, have maintained a certain yearning for that rough edge and that we do so with a glass of fine ale rather than wine. We have found the grape vintages a wee too refined for our palates during a good listening session. We have also noted that the serving vessel might well come into play here. It appears the long stemmed vessels do indeed have a difficult time staying in one spot and tend to rattle about the place a bit, even so much as to offer their contents to the heavily underlaid berber below. This is but one of the reasons I wish to mention the practical side of a non-leaded, straight sided, handled version. Not only are they sturdy, but they offer a better opportunity to connect with your close friends.
Besides, there's just something about pulling on a tap that seems so satisfying.
Cheers
Oops, back to topic
I enjoyed reading the last paragraph of your post.
While I concur with your thoughts of refinement, may I be so bold as to suggest that some, myself included, have maintained a certain yearning for that rough edge and that we do so with a glass of fine ale rather than wine. We have found the grape vintages a wee too refined for our palates during a good listening session. We have also noted that the serving vessel might well come into play here. It appears the long stemmed vessels do indeed have a difficult time staying in one spot and tend to rattle about the place a bit, even so much as to offer their contents to the heavily underlaid berber below. This is but one of the reasons I wish to mention the practical side of a non-leaded, straight sided, handled version. Not only are they sturdy, but they offer a better opportunity to connect with your close friends.
Besides, there's just something about pulling on a tap that seems so satisfying.
Cheers
Oops, back to topic
punkrokr1701,
As you mentioned earlier in the thread, this is not easy for someone your age to understand, but many of us did start out that young. I started when I was 15 and went from being extremely overwhelmed to helping BrianGT write the instruction manual for the LM3886 amp kit. These people helping you are not only extremely helpful, but extremely kind and caring. You are lucky to have so many well respected members helping you out and giving you such great feed back.
I must say, I am bit confused as to why you need it sooo loud. I just moved out of my parent's house, now in a dorm room and not sure, haven't checked my spl meter recently on the levels i listen to here, but 120db at listening posistion is pretty crazy. Personally I don't want to listen to music that loud. When its that loud you can't hear detail, you just hear screaming.
Here at NC State I have asked many of my friends to guess how many watts my amplifier is. I had someone tell me they thought it was over 500watts. They were very surprised (and felt rather stupid) to find out that it is only an 8 watt amplifier. My amp paired with my FE127s is more then enough power than I will use. I have plenty of headroom and impress all the ladies as well .
Throughout high school I built many subwoofers for friends and helped friends pick out systems, for years and still get phone calls every couple months asking about which subs to get for their car. I've heard plenty of systems that get over 120db, sure they are fun, but you can not only destroy your ears, but your car too. My website doesn't have many pictures on it from some of the subs I have built, and not enough of my current subwoofers. I'm not sure how your parents are, but mine didn't like it so much when I made a picture fall of the wall. Not only that, but mom would tell me that i have to finish all my projects and if i showed her a design, she may say "No, that is too big, you are not bringing that into MY HOUSE!"
Take your time! Read! Listen to what others are telling you. Basic Car Audio Electronics is a great website with tons of information, it is not just car audio, it is audio in general and is easy to read for anyone. Also understand T/S Parameter . You seems to be well past this, but just as a reference go to How Stuff Works.com .
Good Luck, Listen to these wise folks here,
Josh
As you mentioned earlier in the thread, this is not easy for someone your age to understand, but many of us did start out that young. I started when I was 15 and went from being extremely overwhelmed to helping BrianGT write the instruction manual for the LM3886 amp kit. These people helping you are not only extremely helpful, but extremely kind and caring. You are lucky to have so many well respected members helping you out and giving you such great feed back.
I must say, I am bit confused as to why you need it sooo loud. I just moved out of my parent's house, now in a dorm room and not sure, haven't checked my spl meter recently on the levels i listen to here, but 120db at listening posistion is pretty crazy. Personally I don't want to listen to music that loud. When its that loud you can't hear detail, you just hear screaming.
Here at NC State I have asked many of my friends to guess how many watts my amplifier is. I had someone tell me they thought it was over 500watts. They were very surprised (and felt rather stupid) to find out that it is only an 8 watt amplifier. My amp paired with my FE127s is more then enough power than I will use. I have plenty of headroom and impress all the ladies as well
. Throughout high school I built many subwoofers for friends and helped friends pick out systems, for years and still get phone calls every couple months asking about which subs to get for their car. I've heard plenty of systems that get over 120db, sure they are fun, but you can not only destroy your ears, but your car too. My website doesn't have many pictures on it from some of the subs I have built, and not enough of my current subwoofers. I'm not sure how your parents are, but mine didn't like it so much when I made a picture fall of the wall. Not only that, but mom would tell me that i have to finish all my projects and if i showed her a design, she may say "No, that is too big, you are not bringing that into MY HOUSE!"
Take your time! Read! Listen to what others are telling you. Basic Car Audio Electronics is a great website with tons of information, it is not just car audio, it is audio in general and is easy to read for anyone. Also understand T/S Parameter . You seems to be well past this, but just as a reference go to How Stuff Works.com .
Good Luck, Listen to these wise folks here,
Josh
ok, here I rant again!
Andrew T, wouldn't we all like the PD drivers?
''. As an aside , I suggest you check out Hemp's new drivers.. (again, at least they seem good based on previous reviews--I'll let ya know cause apparently I'm gonna be gettin a pair). Cool thing is that no fancy schmancy enclosure is required
Punkr, Without seeming too obnoxious,this is getting old fast. ''
Several excellent ideas, all trying to stay within a budget. We don't know a budget, nor your existing system can we prythat away from you?
Perhaps if Cal Weldon's old enclosure , new equipment idea @$3k is in your budget cetainly that's an idea. still no information regarding your existing equipment . we area all (ok at least I am ) assuming that you need as a minimum some kind of amplifier and a pair of loudspeakers.
Andrew, the 4 ft^3 boxes using the Emmenence driver/tweeters/x-overs are something like 98 db + @ 1Watt@1 meter. That's from just a coaxial woofer/horn tweeter/xover in a simple rectangular box, no horn loading. If more bass was required a horn loaded sub could be added in the future (or a pair) . The 120 dB max is limited by the speaker, not the amp.
edjosh23 , I don't think punkr is interested in car audio yet, it was an example of (sic) big bass. Lots of hearing loss has occurrred all over Europe and North America (and Asia too) concerning that. As I don't know the book that you linked to, I have to believe that based on past posts from you that it is a good one with good explainations. Punkr really needs a basic instruction in electronics (just passive components), and Ohms law and he may be on the way.
8 watts is really cool and I am sure your "dorm" system is very good. Proof good taste is not indicative of age , but rather experience.
Punkr, if you want to learn to tune a cabinet, search for "Helmholtz equation" and apply it to a loudspeaker enclosure. The T/S parameters and the Helmholtz equation are what determines the enclosure size and tuning, as well as the "Q" of the enclosure which is indicative of the Quality of the Bass, not the amount.
Hope it all helps. Email me if you choose to. Take care all. goodnight.
Andrew T, wouldn't we all like the PD drivers?
'
'. As an aside , I suggest you check out Hemp's new drivers.. (again, at least they seem good based on previous reviews--I'll let ya know cause apparently I'm gonna be gettin a pair). Cool thing is that no fancy schmancy enclosure is requiredPunkr, Without seeming too obnoxious,this is getting old fast. '
'Several excellent ideas, all trying to stay within a budget. We don't know a budget, nor your existing system can we prythat away from you?
Perhaps if Cal Weldon's old enclosure , new equipment idea @$3k is in your budget cetainly that's an idea. still no information regarding your existing equipment . we area all (ok at least I am ) assuming that you need as a minimum some kind of amplifier and a pair of loudspeakers.
Andrew, the 4 ft^3 boxes using the Emmenence driver/tweeters/x-overs are something like 98 db + @ 1Watt@1 meter. That's from just a coaxial woofer/horn tweeter/xover in a simple rectangular box, no horn loading. If more bass was required a horn loaded sub could be added in the future (or a pair) . The 120 dB max is limited by the speaker, not the amp.
edjosh23 , I don't think punkr is interested in car audio yet, it was an example of (sic) big bass. Lots of hearing loss has occurrred all over Europe and North America (and Asia too) concerning that. As I don't know the book that you linked to, I have to believe that based on past posts from you that it is a good one with good explainations. Punkr really needs a basic instruction in electronics (just passive components), and Ohms law and he may be on the way.
8 watts is really cool and I am sure your "dorm" system is very good. Proof good taste is not indicative of age , but rather experience.
Punkr, if you want to learn to tune a cabinet, search for "Helmholtz equation" and apply it to a loudspeaker enclosure. The T/S parameters and the Helmholtz equation are what determines the enclosure size and tuning, as well as the "Q" of the enclosure which is indicative of the Quality of the Bass, not the amount.
Hope it all helps. Email me if you choose to. Take care all. goodnight.
mashaffer said:
An externally hosted image should be here but it was not working when we last tested it.
Don't forget the L-pads needed for the mid and tweeter.
/sreten.
Nanook,
I mentioned car audio because he seems to want "sick" bass. As many of the members on the forum, including Shin (i mention you because i remember reading something about it when you were younger), myself, and probably many of you all, when we were younger we wanted bass in our cars and homes to show off and rattle things off the wall, but quickly we learn that there is more than just big bass.
Those Hemp drivers would be great in a BIB. They get very loud, don't need a lot of amplification, no xo, and get low bass.
Punkr,
These members are being very nice and helpful, read and listen to them. Understand what you are doing before building. Listen to their suggestions!
Josh
I mentioned car audio because he seems to want "sick" bass. As many of the members on the forum, including Shin (i mention you because i remember reading something about it when you were younger), myself, and probably many of you all, when we were younger we wanted bass in our cars and homes to show off and rattle things off the wall, but quickly we learn that there is more than just big bass.
Those Hemp drivers would be great in a BIB. They get very loud, don't need a lot of amplification, no xo, and get low bass.
Punkr,
These members are being very nice and helpful, read and listen to them. Understand what you are doing before building. Listen to their suggestions!
Josh
ok, I was putting together someplans and I'm stumped to as exactly how to build the enclosure for a subwoofer.
I can't exactly put what I want to say in word so I give the description of the subwoofer I'm using.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-420
Ok, so could just explain to me what exactly the measurements of the enclosure should be of I wanted a Vas of 7.79 to 8 cu.ft. please?
I know this is no where near enough info I just want to know what the dimensions of the enclosure should be for a vas of the stated 7.79 to 8 cu.ft.
To me this SEEMS like basic math at first cause l*w*h = cubic unit, right but when I went to plan my enclosure it seemed to be encredibly small.
or Vas not what is used to measure the enclosure size?
well, I'm lost here
all I know is that I'm using two 6" inch ports, the first two dimensions have to be 20"x16" and I want an enclosure that will make the MKIII pump out more than enough heavy bass,
So what I'm really asking for is that last dimension.
And thanx guys, you've already been a huge help and I'm forever sorry I ever doubted anyone here.
I can't exactly put what I want to say in word so I give the description of the subwoofer I'm using.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-420
Ok, so could just explain to me what exactly the measurements of the enclosure should be of I wanted a Vas of 7.79 to 8 cu.ft. please?
I know this is no where near enough info I just want to know what the dimensions of the enclosure should be for a vas of the stated 7.79 to 8 cu.ft.
To me this SEEMS like basic math at first cause l*w*h = cubic unit, right but when I went to plan my enclosure it seemed to be encredibly small.
or Vas not what is used to measure the enclosure size?
well, I'm lost here
all I know is that I'm using two 6" inch ports, the first two dimensions have to be 20"x16" and I want an enclosure that will make the MKIII pump out more than enough heavy bass,
So what I'm really asking for is that last dimension.
And thanx guys, you've already been a huge help and I'm forever sorry I ever doubted anyone here.
This driver is less than optimum for a vented enclosure. If you did go vented, the two 6" vents would want to be 5.6' long. This can be a resonance problem. To get them down to 1' long, you'd want to use a single 4" vent, which won't be large enough to let all that air through at high volumes.
This driver would work in a 2.5 cu ft sealed enclosure with a -3dB point of around 40Hz. If your first two dimensions are 20" and 16", then the third would be 13".
This driver would work in a 2.5 cu ft sealed enclosure with a -3dB point of around 40Hz. If your first two dimensions are 20" and 16", then the third would be 13".
punkr,
I don't have time to calculate an enclosure for you, and i think ti would be best for you to learn that yourself, but here is some explanations.
A square foot is 12"x12"x12" which equals 1728"^3.
And you say you want your footprint to be 16"x20".
Lets say the enclosure could be 4' tall. Therefore your enclosure (these are internal dimensions not external) 16"x20"x48" = 15360"^3. Divide that number by 1 square foot (15360/1728) = 8.88ft^3. You actually need an enclosure around 6.5ft^3. Read those websites so that you understand what you are doing. And you can try and download WinISD or UniBox to help design enclosures.
Josh
I don't have time to calculate an enclosure for you, and i think ti would be best for you to learn that yourself, but here is some explanations.
A square foot is 12"x12"x12" which equals 1728"^3.
And you say you want your footprint to be 16"x20".
Lets say the enclosure could be 4' tall. Therefore your enclosure (these are internal dimensions not external) 16"x20"x48" = 15360"^3. Divide that number by 1 square foot (15360/1728) = 8.88ft^3. You actually need an enclosure around 6.5ft^3. Read those websites so that you understand what you are doing. And you can try and download WinISD or UniBox to help design enclosures.
Josh
Never mind my last post.
After a little brain power I remembered my algebra and geometry classes. So I got the box for that sub settled.
Now I've got a questio in the matter of frequency.
I'm using once again anothe Dayton Audio MKIII 15" subwoofer.
The enclosuure is 6.125 cu.ft. and I plan to mount one of these
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-713
on each corner of the driver.
I was wonderong about what frequency would this tune my enclosure to?
I want this to sound more like a sealed subwoofer with more precise, and accurate hits but I'm not going to seal off this sub because of the amount of air it needs.
Would those four triangular ports come close enough to a sealed sub? Or do I need to downsize?
And what exactly is Vas?
Is it the amount of space need for a ported apllication or something else?
Hey, I was just reading back on some of my earlier posts and WOW you guys have tought me alot and I am realizing that even though I didn't know at first I was begining after your first few replies.
Once again thanx a million.
You guys are the best!
Cheers!
After a little brain power I remembered my algebra and geometry classes. So I got the box for that sub settled.
Now I've got a questio in the matter of frequency.
I'm using once again anothe Dayton Audio MKIII 15" subwoofer.
The enclosuure is 6.125 cu.ft. and I plan to mount one of these
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=260-713
on each corner of the driver.
I was wonderong about what frequency would this tune my enclosure to?
I want this to sound more like a sealed subwoofer with more precise, and accurate hits but I'm not going to seal off this sub because of the amount of air it needs.
Would those four triangular ports come close enough to a sealed sub? Or do I need to downsize?
And what exactly is Vas?
Is it the amount of space need for a ported apllication or something else?
Hey, I was just reading back on some of my earlier posts and WOW you guys have tought me alot and I am realizing that even though I didn't know at first I was begining after your first few replies.
Once again thanx a million.
You guys are the best!
Cheers!
Thanks Sreten, I did forget to mention the pads.
Vas is a parameter of the driver that affects the size requirement of the box but it is not the size of the box itself.
For example a maximally flat response for that driver wants a box of 6.66 ft^3 but you could also tune it a bit lower and increase the size to say 11.5 ft^3 which would extend your -3dB point down to 17Hz rather than the 21 or 22Hz of the smaller box. There is also a bit of a slope to the response in the bigger box that could help overcome room effects in some situations. Of course you could also put it in a sealed box of about 2.5 ft^3 volume. This would raise the -3dB point to about 35Hz but this could sound very nice in some rooms and would be an easier box to get right (more forgiving). It is also, as you can see, much smaller which may be a factor. And for Rock and Roll that response is not unreasonable. You could even make the seal box as small as 1.5 ft^3 and you would get a slight bump in the midbass that is not very high fidelity but is often favored by rockers and rappers.
So you see the choices are almost endless depending on what you are trying to do and the room where you will be using it.
As to calculating volume (box plot will do it for you) all you have to do is divide the inside dimensions (in inches) by 12. Then multiply HxDxW to get the volume. so lets take the first ported design
6.66=h*(16/12)*(20/12)=h*1.333*1.666=h*2.221
So dividing both sides by 2.221 we get
h=6.66/2.221=3 feet or 36"
Now that was assuming that you gave me inside dimensions. If it was outside dimensions then you need to subtract twice the material thickness from each dimension. You also want to add a bit to the target volume to account for the volume taken up by the driver itself. You can estimate that or measure it but most people don't get that precise as to measure the volume taken up by the driver.
Clear as mud?
mike
P.S. Do download those free box design programs. You will learn tons by playing with them. The Parts Express catalog and website give all the parameters you need to simulate boxes in these programs. The WinISD is all metric but if you get BoxPlot you can enter all the english parameters in the driver input box and then just hit the metric radio button to convert them all at once. Very slick.
On thing that is confusing in BoxPlot is that the box parameter dialog does not allow you to specify size and tuning frequency directly. Rather you have to manipulate two other parameters called H and Alpha. H effects tuning and Alpha effects size. Lower H to tune lower. Lower Alpha to make the box bigger. Hitting the Align button gives you the maximally flat vented alignment. The box dimensions dialog will show the resulting box size while the vent design dialog will sugest a porting that you can modify by adding more vents or changing their diameter. Try for Mach speed under 0.14.
Play play play.
Vas is a parameter of the driver that affects the size requirement of the box but it is not the size of the box itself.
For example a maximally flat response for that driver wants a box of 6.66 ft^3 but you could also tune it a bit lower and increase the size to say 11.5 ft^3 which would extend your -3dB point down to 17Hz rather than the 21 or 22Hz of the smaller box. There is also a bit of a slope to the response in the bigger box that could help overcome room effects in some situations. Of course you could also put it in a sealed box of about 2.5 ft^3 volume. This would raise the -3dB point to about 35Hz but this could sound very nice in some rooms and would be an easier box to get right (more forgiving). It is also, as you can see, much smaller which may be a factor. And for Rock and Roll that response is not unreasonable. You could even make the seal box as small as 1.5 ft^3 and you would get a slight bump in the midbass that is not very high fidelity but is often favored by rockers and rappers.
So you see the choices are almost endless depending on what you are trying to do and the room where you will be using it.
As to calculating volume (box plot will do it for you) all you have to do is divide the inside dimensions (in inches) by 12. Then multiply HxDxW to get the volume. so lets take the first ported design
6.66=h*(16/12)*(20/12)=h*1.333*1.666=h*2.221
So dividing both sides by 2.221 we get
h=6.66/2.221=3 feet or 36"
Now that was assuming that you gave me inside dimensions. If it was outside dimensions then you need to subtract twice the material thickness from each dimension. You also want to add a bit to the target volume to account for the volume taken up by the driver itself. You can estimate that or measure it but most people don't get that precise as to measure the volume taken up by the driver.
Clear as mud?
mike
P.S. Do download those free box design programs. You will learn tons by playing with them. The Parts Express catalog and website give all the parameters you need to simulate boxes in these programs. The WinISD is all metric but if you get BoxPlot you can enter all the english parameters in the driver input box and then just hit the metric radio button to convert them all at once. Very slick.
On thing that is confusing in BoxPlot is that the box parameter dialog does not allow you to specify size and tuning frequency directly. Rather you have to manipulate two other parameters called H and Alpha. H effects tuning and Alpha effects size. Lower H to tune lower. Lower Alpha to make the box bigger. Hitting the Align button gives you the maximally flat vented alignment. The box dimensions dialog will show the resulting box size while the vent design dialog will sugest a porting that you can modify by adding more vents or changing their diameter. Try for Mach speed under 0.14.
Play play play.
a bunch more stuff.
Punkr, please are you now looking at subs as well as full range type PA systems? How about an equipment list (of what you have), what you feel you need and at least some indication of a budget.? If a couple of subs are in the works (and you get your boring old MTMs back from your buddy), then ya build some. Over all perhaps a good option.
Understanding various loudspeaker parameters takes some experience, but someplace there must be a Thiel Small loudspeaker parameter explanation.
Here's WinISD an excellent program and available for free download.
Here's a good page, on subwoofers that has a nice "definition" page DIY Subwoofers for Thiel Small parameters
Ok and look at the "Helmholtz equation" (that's for understanding basic resonator behaviour , which any tuned enclosure is) and do a search for basic electrical behaviour, Ohm's law, etc. Until you understand that ( resistors in series add one way, while in parallel adds a different,, understand the capacitors have inverse mathematical relations to resistor addition and what and how inductance and reactance behave), you will be just be fishing..
Done .fini, finito.
Good luck
Punkr, please are you now looking at subs as well as full range type PA systems? How about an equipment list (of what you have), what you feel you need and at least some indication of a budget.? If a couple of subs are in the works (and you get your boring old MTMs back from your buddy), then ya build some. Over all perhaps a good option.
Understanding various loudspeaker parameters takes some experience, but someplace there must be a Thiel Small loudspeaker parameter explanation.
Here's WinISD an excellent program and available for free download.
Here's a good page, on subwoofers that has a nice "definition" page DIY Subwoofers for Thiel Small parameters
Ok and look at the "Helmholtz equation" (that's for understanding basic resonator behaviour , which any tuned enclosure is) and do a search for basic electrical behaviour, Ohm's law, etc. Until you understand that ( resistors in series add one way, while in parallel adds a different,, understand the capacitors have inverse mathematical relations to resistor addition and what and how inductance and reactance behave), you will be just be fishing..
Done .fini, finito.
Good luck
Hi Punkrok,
Vas is a driver parameter (characteristic).
It is the stiffness of the suspension.
It is specified by equating the stiffness to an equivalent volume of air.
So if the Vas is 6cubft then that is telling you that the cone suspension has the same stiffness as 6cubft of air trapped in a sealed enclosure behind the speaker.
The other really important parameter is Qts. Without it and Vas you cannot start a design. You can guess, but more likely you will quess one hundred times and build one hundred wrong boxes, some of which will sound terrible and a few might just be good enough to sound mediocre.
When you get around to designing the box's internal volume remember to subtract the driver volume, bracing volume and the port volume from the internal volume to get the box volume.
Vas is a driver parameter (characteristic).
It is the stiffness of the suspension.
It is specified by equating the stiffness to an equivalent volume of air.
So if the Vas is 6cubft then that is telling you that the cone suspension has the same stiffness as 6cubft of air trapped in a sealed enclosure behind the speaker.
The other really important parameter is Qts. Without it and Vas you cannot start a design. You can guess, but more likely you will quess one hundred times and build one hundred wrong boxes, some of which will sound terrible and a few might just be good enough to sound mediocre.
When you get around to designing the box's internal volume remember to subtract the driver volume, bracing volume and the port volume from the internal volume to get the box volume.
Umm, I was just wondering...
how exactly do you guys calculate the frequency of a cabinet?
If it's some big long complicated process you don't have to bother but it'd be nice to know.
And is that 11.5ft^3 enclosure with or without ports?
And if the first two dimensions of an sub enclosure are 24"x28"
how could I make the lowest possible tuned enclosure?
Basically, what would the third dimension be ( preferably with some sort of assortment of ports)?
how exactly do you guys calculate the frequency of a cabinet?
If it's some big long complicated process you don't have to bother but it'd be nice to know.
And is that 11.5ft^3 enclosure with or without ports?
And if the first two dimensions of an sub enclosure are 24"x28"
how could I make the lowest possible tuned enclosure?
Basically, what would the third dimension be ( preferably with some sort of assortment of ports)?
I have not calculated VAS excactly but estimated VAS 250liter and Qtc=0.6, and it gives a sensible box volume, 150liter
http://www.mhsoft.nl/spk_calc.asp#sealed
http://www.mhsoft.nl/spk_calc.asp#sealed
Aloha Punkrokr,
I've been following this thread with interest. Maybe it's time to think "Outside the Box." Boxes? We don't need no stinkin' Boxes!
This is what you want: WMTMW Open Baffle
Now those will knock your socks off. Blow the hair right off the family dog, too.
If you really have the room and the budget, something like that will impress ANYONE. Read that thread, I think you'll like it. Those 21" Madisons will be the envy of anyone who sees them. Remember McFly's guitar amp in "Back to the Future?"
A buddy of mine in California built some amazing Open Baffle speaks last year. You can see them in my post 1/2 way down the page. They look small, but they are NOT. That's 2 18" drivers and a 12" as the mid! Heart rending bass, my friend. Not for sissies. And u can build them taller, since you want speakers taller than your buddies who come over to listen.
The open baffle stuff will have very clean bass, clean mids too. But you have to throw some power at it. I don't think you're afraid of that. And the bass will need to be EQ'd to get solid lows. Open Baffle is like that. But it can be done.
No worries about box tuning, then.
Does that float your boat?
I've been following this thread with interest. Maybe it's time to think "Outside the Box." Boxes? We don't need no stinkin' Boxes!
This is what you want: WMTMW Open Baffle
Now those will knock your socks off. Blow the hair right off the family dog, too.
If you really have the room and the budget, something like that will impress ANYONE. Read that thread, I think you'll like it. Those 21" Madisons will be the envy of anyone who sees them. Remember McFly's guitar amp in "Back to the Future?"
A buddy of mine in California built some amazing Open Baffle speaks last year. You can see them in my post 1/2 way down the page. They look small, but they are NOT. That's 2 18" drivers and a 12" as the mid! Heart rending bass, my friend. Not for sissies. And u can build them taller, since you want speakers taller than your buddies who come over to listen.
The open baffle stuff will have very clean bass, clean mids too. But you have to throw some power at it. I don't think you're afraid of that. And the bass will need to be EQ'd to get solid lows. Open Baffle is like that. But it can be done.
No worries about box tuning, then.
Does that float your boat?
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