If you were to flow chart the process for designing a sub woofer, what would it look like?
I am guessing that the first place to start would be determining the parameters? Room Size? Type of use?Primarly music, primarily HT, 50/50 split Music/HT, etc)? What other type of parameters should one consider?
If there is another step before this, what is it? What would be the next series of steps?
Hopefully if we have enough feedback we can develop something that will be of aid to all newbie sub (or speaker) builders in this forum.
Look forward to hearing from everyone
I am guessing that the first place to start would be determining the parameters? Room Size? Type of use?Primarly music, primarily HT, 50/50 split Music/HT, etc)? What other type of parameters should one consider?
If there is another step before this, what is it? What would be the next series of steps?
Hopefully if we have enough feedback we can develop something that will be of aid to all newbie sub (or speaker) builders in this forum.
Look forward to hearing from everyone
Room size
spl required at seating
extension ( -3 point in room)
space available for subs
amp power available
budget (the bit where you find out the above is not possible for the money in your wallet
😀 )
Vented / sealed/ tl /horn etc is more personal taste, but may be important to hit your f-3 / spl targets within budget. (sealed systems ~generally~ need more drivers for spl, but give more output way down deep)
Also need to consider your room gain and if you want to build in any headroom into the system.
Thats kind of what my head thinks like.
Rob.
spl required at seating
extension ( -3 point in room)
space available for subs
amp power available
budget (the bit where you find out the above is not possible for the money in your wallet
😀 )Vented / sealed/ tl /horn etc is more personal taste, but may be important to hit your f-3 / spl targets within budget. (sealed systems ~generally~ need more drivers for spl, but give more output way down deep)
Also need to consider your room gain and if you want to build in any headroom into the system.
Thats kind of what my head thinks like.
Rob.
I go the other way.
"What kind of sub do I want?" (TL, Horn, Vented, PR, Sealed)
"How low and how much powerhandling and output do I need?"
"How big is this going to have to be?"
"Where do I get all the parts, and how much do they cost? Where can I get them more affordably? (shopping is important for drivers, lots of good drivers out there at reasonable prices, if you just look)"
"How am I going to shoehorn this into the room?!"
"What kind of sub do I want?" (TL, Horn, Vented, PR, Sealed)
"How low and how much powerhandling and output do I need?"
"How big is this going to have to be?"
"Where do I get all the parts, and how much do they cost? Where can I get them more affordably? (shopping is important for drivers, lots of good drivers out there at reasonable prices, if you just look)"
"How am I going to shoehorn this into the room?!"
I think Rob is on the right track as well.
I guess what I am looking for is how do you make the leap from these parameters (room size, type of use, spl levels , extension, and vented/ sealed/etc. passive (available amp already?) or active) to determining the specifications from which you could choose a driver(s) that would meet your needs. And then look and see if your 'wants' fall within your budget or are you going to have to back off on what you would like in order to fit within your budget.
This is definately an iterative process where if the outcome is not reasonable (to much money, to many drivers, to large enclosure), one would have to go back and tweak the parameters until you could find a compromise between what one wants and what one can realistically have.
I guess what I am looking for is how do you make the leap from these parameters (room size, type of use, spl levels , extension, and vented/ sealed/etc. passive (available amp already?) or active) to determining the specifications from which you could choose a driver(s) that would meet your needs. And then look and see if your 'wants' fall within your budget or are you going to have to back off on what you would like in order to fit within your budget.
This is definately an iterative process where if the outcome is not reasonable (to much money, to many drivers, to large enclosure), one would have to go back and tweak the parameters until you could find a compromise between what one wants and what one can realistically have.
I don't think that things have to come in a particular order. There has to be several iteration loops, including simulations and testing several alternatives of drivers and box types.
I would go this way....
1.Determine size restrictions
2.Detemine budget
3.Decide Driver and enclosure type based on size restrictions and personal preference
4.Choose an appropriate amplifier
Instead of starting with ideal and working backwards to something you can actually achieve... I would start with what is achieveable and work towards making that more ideal...
Its easy to determine where you have space available for a subwoofer and how much of it you're willing to sacrifice... It's also easy to determine approximately how much you're willing to spend on a project... So with those things in mind you can look at specific enclosure types(based on your preference) and drivers that work well in them that fit your budget with room for the purchase of a amplifier which would work well with the driver...
Step 3 includes determining the tradeoff between cutoff and SPL goals
Step 3 in my process SHOULD also include the thought of what kind of amp you will be able to afford based on the cost of the driver and what it's power requirements and impedence are, plus what kind of functional features you'd like your amp to include(EQ etc...). I just wanted to keep things simple-like
1.Determine size restrictions
2.Detemine budget
3.Decide Driver and enclosure type based on size restrictions and personal preference
4.Choose an appropriate amplifier
Instead of starting with ideal and working backwards to something you can actually achieve... I would start with what is achieveable and work towards making that more ideal...
Its easy to determine where you have space available for a subwoofer and how much of it you're willing to sacrifice... It's also easy to determine approximately how much you're willing to spend on a project... So with those things in mind you can look at specific enclosure types(based on your preference) and drivers that work well in them that fit your budget with room for the purchase of a amplifier which would work well with the driver...
Step 3 includes determining the tradeoff between cutoff and SPL goals
Step 3 in my process SHOULD also include the thought of what kind of amp you will be able to afford based on the cost of the driver and what it's power requirements and impedence are, plus what kind of functional features you'd like your amp to include(EQ etc...). I just wanted to keep things simple-like
I would use the flow chart published by WJJ Hoge in Audio magazine, an article entitled "Confessions of a Loudspeaker Designer." Some library work ought to turn it up. If I run across it, I'll scan the chart and post.
Thanks Sy, that would be most useful to put up and let everyone discuss it.
One other thing, what are the characteristics that one would want if the sub was being used for:
HT?
Music?
50% Music / 50% HT?
I know you want more thump for home theatre, but can you have good clean accurate bass as well or is there a trade off.
One other thing, what are the characteristics that one would want if the sub was being used for:
HT?
Music?
50% Music / 50% HT?
I know you want more thump for home theatre, but can you have good clean accurate bass as well or is there a trade off.
IMO the requirements for a music vs cinema sub are the same except that for cinema use it must be able to kick out a lot more SPL.
Thanks Sy, that would be most useful to put up and let everyone discuss it.
One other thing, what are the characteristics that one would want if the sub was being used for:
HT?
Music?
50% Music / 50% HT?
I know you want more thump for home theatre, but can you have good clean accurate bass as well or is there a trade off.
One other thing, what are the characteristics that one would want if the sub was being used for:
HT?
Music?
50% Music / 50% HT?
I know you want more thump for home theatre, but can you have good clean accurate bass as well or is there a trade off.
richie00boy said:
well how much would be minimum?
20hz? (100dB?)
30hz? (107dB?)
.
.
.
also we should define the room size.
small 3 x 4 m
meduim 5 x 6 m
large 7 x 8m and bigger
what SPL levels shoud a realy good sub reach(also for HT use) in such rooms?
The SPL requirements of the sub will depend on what is achievable with the main speakers, and the listeners taste. I don't think room size comes into it.
What room size (and construction) will dictate however, is the frequency that the sub should be designed to get down to.
What room size (and construction) will dictate however, is the frequency that the sub should be designed to get down to.
I uderstand that with time, practice and experience, designing and building a sub will become easier because you know what results your looking for and what variables you can change to meet your constraints (size, budget, etc.).
As I had said before this is obviously an iterative process, but one needs to know where one is going before they can get there. I know the concept of a sub, like any speaker is subjective to the listener and there are many variables that can be modeled and many variables that can't be modeled.
Maybe there is no 'simplified' methodology to follow when considering how to design a sub. Maybe it is all trial and error. I know speaking from experiance that the WAF is very low with trial and error method when you have to order drivers from the US and then end up creating a pile of them in the back work room because they don't quite work for you...
As I had said before this is obviously an iterative process, but one needs to know where one is going before they can get there. I know the concept of a sub, like any speaker is subjective to the listener and there are many variables that can be modeled and many variables that can't be modeled.
Maybe there is no 'simplified' methodology to follow when considering how to design a sub. Maybe it is all trial and error. I know speaking from experiance that the WAF is very low with trial and error method when you have to order drivers from the US and then end up creating a pile of them in the back work room because they don't quite work for you...
For dolby digital it asks for 115dB from the sub at seating, 122dB if all speakers set to small. If you want to watch films at reference level.
From that you can subtract your room gain, whether you only watch at -10dB etc.
That will put you in the spl area you require. Then you can look at the trade offs between size / extension you want / budget / type of sub etc. These all depend on the person who is building a sub. If budget is a factor then that will probably push towards lower numbers of drivers using ports or TL's to get the bass up.
If more drivers are avaible then sealed becomes viable.
If theres huge space available and the missus loves you enough then horns can be an option. 😀
For an example, my room is 21' x 10' x~9' high. I get a measured 10dB gain at 15Hz. I want to listen to films at reference, flat to 15Hz, with all my speakers set to small. Therefore I need to hit 111dB at 15Hz.
1 tempest does around 97dB @ 15hz max. 4 will do 109dB. Thats close enough for me, and what I did a few years back.
You also get some gain from placing the subs in a corner, and thats my headroom for this room. ( theory from searches here says anything from 0dB - 12dB gain)
In reality a pair would probably have sufficed.
hth a bit.
From that you can subtract your room gain, whether you only watch at -10dB etc.
That will put you in the spl area you require. Then you can look at the trade offs between size / extension you want / budget / type of sub etc. These all depend on the person who is building a sub. If budget is a factor then that will probably push towards lower numbers of drivers using ports or TL's to get the bass up.
If more drivers are avaible then sealed becomes viable.
If theres huge space available and the missus loves you enough then horns can be an option. 😀
For an example, my room is 21' x 10' x~9' high. I get a measured 10dB gain at 15Hz. I want to listen to films at reference, flat to 15Hz, with all my speakers set to small. Therefore I need to hit 111dB at 15Hz.
1 tempest does around 97dB @ 15hz max. 4 will do 109dB. Thats close enough for me, and what I did a few years back.
You also get some gain from placing the subs in a corner, and thats my headroom for this room. ( theory from searches here says anything from 0dB - 12dB gain)
In reality a pair would probably have sufficed.
hth a bit.
200L that is a lot of space!
ot:
I try to find smaller solution. For now I think of doing similar project like Tony Gee did with PD2150. It means use some profi driver put into small closed box(up to 80L) and equalize.
is it a good idea? if yes which driver would you choose and why?
I think I saw some of your measurements of beyma 15lx60 in closed box. Do you think they are suitable?
links to Gee's project:
http://www.diyaudio.com/forums/showthread.php?postid=874333#post874333
http://www.diyaudio.com/forums/showthread.php?postid=876075#post876075
ot:
I try to find smaller solution. For now I think of doing similar project like Tony Gee did with PD2150. It means use some profi driver put into small closed box(up to 80L) and equalize.
is it a good idea? if yes which driver would you choose and why?
I think I saw some of your measurements of beyma 15lx60 in closed box. Do you think they are suitable?
links to Gee's project:
http://www.diyaudio.com/forums/showthread.php?postid=874333#post874333
http://www.diyaudio.com/forums/showthread.php?postid=876075#post876075
Yep 600L total for 3 subs. (never got round to building a cab for the 4th driver, even though I have it)
I haven't heard the 2150 driver so can't comment, but have only ever read good things about it.
The beymas were great for midbass, but for real sub duty I doubt they'd cut it - If I wanted them to go low I'd probably port them to get down to the 40's then use a 'conventional' home sub below that. I'm pretty confident the lx60 would sound way better in the 40 - 100Hz range than my tempests.
Have you seen the price of the pd2150 yet ?
Theres another pro based sub here
Personally I use labhorns now for subs.
Cheers,
Rob.
I haven't heard the 2150 driver so can't comment, but have only ever read good things about it.
The beymas were great for midbass, but for real sub duty I doubt they'd cut it - If I wanted them to go low I'd probably port them to get down to the 40's then use a 'conventional' home sub below that. I'm pretty confident the lx60 would sound way better in the 40 - 100Hz range than my tempests.
Have you seen the price of the pd2150 yet ?
Theres another pro based sub here
Personally I use labhorns now for subs.
Cheers,
Rob.
yeah I seen 🙂 thats why I look for different driver 🙂
I have look for Almighty Subwoofers earlier but I don't know where to buy JBL drivers here in Czech Republic.
do you think they would be even better than Labhorns?
Do you know of some other drivers to fit in almighty subs?
regards Marek
I have look for Almighty Subwoofers earlier but I don't know where to buy JBL drivers here in Czech Republic.
do you think they would be even better than Labhorns?
Do you know of some other drivers to fit in almighty subs?
regards Marek
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