Hi Matt, I bookmarked that myself and then went to BJ's online store; they have made a mistake in their listings, the adds for the XO units have had the relevant pricing transposed.
http://cgi.ebay.com.au/NEW-Behringe...photoQQcmdZViewItemQQ_trksidZp1742.m153.l1262
Although the asking price is still good value the 2-way is better to start with, although you could probably make a fixed frequency unit your self a bit cheaper using a circuit board or breadboard
http://cgi.ebay.com.au/NEW-Behringe...photoQQcmdZViewItemQQ_trksidZp1742.m153.l1262
Although the asking price is still good value the 2-way is better to start with, although you could probably make a fixed frequency unit your self a bit cheaper using a circuit board or breadboard
Drivers arrived today.
rabbitz, if the offer still stands I'll take you up on your box drawing.
Dimensions for the tweeter are illustrated here.
For the woofer I've had to hand measure them:
OD: 180mm
MD: 94mm
FT: 7mm
ID: 84mm
CD: 140mm - 144mm (can't measure exactly)
OD, MD, FT, ID, CD abbreviations are in reference to:
For each crossover I'm going to buy a 3.9uF and a 0.1uF Jantzen crosscap, the 2R2 MOX resistor and the 0.6mH inductor from speakerbug. The rest I'll buy from Jaycar.
While I'm on the topic of speakerbug, are there any components (mainly capacitors) worth spending a bit of extra money on with regard to the Pass B1 buffer?
rabbitz, if the offer still stands I'll take you up on your box drawing.
Dimensions for the tweeter are illustrated here.
For the woofer I've had to hand measure them:
OD: 180mm
MD: 94mm
FT: 7mm
ID: 84mm
CD: 140mm - 144mm (can't measure exactly)
OD, MD, FT, ID, CD abbreviations are in reference to:
An externally hosted image should be here but it was not working when we last tested it.
For each crossover I'm going to buy a 3.9uF and a 0.1uF Jantzen crosscap, the 2R2 MOX resistor and the 0.6mH inductor from speakerbug. The rest I'll buy from Jaycar.
While I'm on the topic of speakerbug, are there any components (mainly capacitors) worth spending a bit of extra money on with regard to the Pass B1 buffer?
Matt; time I think for you to start downloading speaker box programs and start playing with sims.
http://www.audio.claub.net/software/jbagby.html
http://www.audiogrid.com/audio/
http://home.earthlink.net/~etunstal/diy.htm
http://www.linearteam.dk/
Start playing, if you decide to go with a sealed box then really the only decision is what volume to make the box, shape is relatively unimportant if you don't want baffle step corrected ( I hardly bother/I cant really hear it ) ported boxes are more difficult but by playing with the programs you can begin to get an idea of how the might sound, and it is a lot easier than building a series of boxes and listening.
May I make a suggestion as to how to proceed??
http://www.audio.claub.net/software/jbagby.html
http://www.audiogrid.com/audio/
http://home.earthlink.net/~etunstal/diy.htm
http://www.linearteam.dk/
Start playing, if you decide to go with a sealed box then really the only decision is what volume to make the box, shape is relatively unimportant if you don't want baffle step corrected ( I hardly bother/I cant really hear it ) ported boxes are more difficult but by playing with the programs you can begin to get an idea of how the might sound, and it is a lot easier than building a series of boxes and listening.
May I make a suggestion as to how to proceed??
Hi Matt
I wouldn't go crazy spending extra dollars on caps for the B1... Nelson Pass said he doesn't lose sleep over caps. Just a good quality MKP is all that is required. I've never used the Janzten Crosscap in an amplifier circuit so have no idea how they perform and I certainly wouldn't waste money on the Z-Cap. My personal preference has been the Mundorf M-Cap (the cheaper white ones) and other builders have there own preferences. The B1 thread mentions a few different types but I don't know if they are available in Oz.
No problem with doing a drawing. I can do it in a few days time as am about to finish a speaker build that's been a PITA (see pic... the baffle has now been scrapped and has to be done again).
For a drawing to be done I need to know a few things about the application and maximum size you can have as that will determine the box sizes.
1. How large can you have it regarding footprint (width x depth) and what height would be your limit?
2. Would narrow (200mm) suit more than a bit wider?
3. How much bass do you expect? This will determine whether a sealed or vented. For sealed (10 litre approx) there will not be a lot under 90Hz and a larger box will not increase this. This would be best suited to sub assistance. A vented can do to 65Hz for a small box (14 litre min) or lower as the box size increases. Usually in a small to medium room I like to get at least 60Hz out of a small 2-way.
Good info on the drivers.... thanks as saves me trying to hunt down info.
I wouldn't go crazy spending extra dollars on caps for the B1... Nelson Pass said he doesn't lose sleep over caps. Just a good quality MKP is all that is required. I've never used the Janzten Crosscap in an amplifier circuit so have no idea how they perform and I certainly wouldn't waste money on the Z-Cap. My personal preference has been the Mundorf M-Cap (the cheaper white ones) and other builders have there own preferences. The B1 thread mentions a few different types but I don't know if they are available in Oz.
No problem with doing a drawing. I can do it in a few days time as am about to finish a speaker build that's been a PITA (see pic... the baffle has now been scrapped and has to be done again).
For a drawing to be done I need to know a few things about the application and maximum size you can have as that will determine the box sizes.
1. How large can you have it regarding footprint (width x depth) and what height would be your limit?
2. Would narrow (200mm) suit more than a bit wider?
3. How much bass do you expect? This will determine whether a sealed or vented. For sealed (10 litre approx) there will not be a lot under 90Hz and a larger box will not increase this. This would be best suited to sub assistance. A vented can do to 65Hz for a small box (14 litre min) or lower as the box size increases. Usually in a small to medium room I like to get at least 60Hz out of a small 2-way.
Good info on the drivers.... thanks as saves me trying to hunt down info.
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rabbitz, thanks for advice on B1.
No hurry on the drawing of course, whenever is convenient!
My room is about 2.5m high, 4.5m long and 2.5m wide.
1 + 2) No limit really. Aesthetically, if it helps give you an idea of what I want. Width roughly two-thirds the height and depth bigger then width.
But honestly, sound is more important then looks anyday.
What say we cap the height at 350mm.
By my calculations 30cmx20cmx25cm (HxWxD) gives a 15L box, around that sounds pretty good in my books.
But I'll leave the final capacity up to you rabbitz as your box knowledge is something I'd like to learn from.
3) I don't exactly listen to bass heavy music, but I don't mind a bit of house/techno now and then. And I don't think I'm going to invest in a sub until I move out/into own place... so I think I might opt for a vented design.
Cheers for those links ted, bit of a learning curve ahaha.
No hurry on the drawing of course, whenever is convenient!
My room is about 2.5m high, 4.5m long and 2.5m wide.
1 + 2) No limit really. Aesthetically, if it helps give you an idea of what I want. Width roughly two-thirds the height and depth bigger then width.
But honestly, sound is more important then looks anyday.
What say we cap the height at 350mm.
By my calculations 30cmx20cmx25cm (HxWxD) gives a 15L box, around that sounds pretty good in my books.
But I'll leave the final capacity up to you rabbitz as your box knowledge is something I'd like to learn from.
3) I don't exactly listen to bass heavy music, but I don't mind a bit of house/techno now and then. And I don't think I'm going to invest in a sub until I move out/into own place... so I think I might opt for a vented design.
Cheers for those links ted, bit of a learning curve ahaha.
It will be done this week.
Could you check the driver and please give me the dimension from top to bottom (see pic) as it's not a round driver. Should be around 174mm. I need this for driver spacing (centres) as we try and get them as close as possible.
I'll do the design so it can cater for vented or sealed and will explain when I post the drawing.
Could you check the driver and please give me the dimension from top to bottom (see pic) as it's not a round driver. Should be around 174mm. I need this for driver spacing (centres) as we try and get them as close as possible.
I'll do the design so it can cater for vented or sealed and will explain when I post the drawing.
Attachments
15 liters may be a good compromise; it will give reasonable bass in a small room and if/when you decide to get a subwoofer the vent could be stuffed ( an old sock filled with polyfill or plastic shopping bags would probably work ) any bigger and they stop being bookshelf speakers in my view and sort of demand stands.
Room placement has a big influence on total/overall sound too.
Rabbitz would routing the tweeter plate to give closer CTC distance have much effect?
Room placement has a big influence on total/overall sound too.
Rabbitz would routing the tweeter plate to give closer CTC distance have much effect?
Moondog55 said:
No benefit here as in theory the drivers would need to be at 90mm centres which is impossible. What we try to do if possible is to have the drivers centres less than the wavelength of the crossover frequency but if that can't be achieved (in a lot of cases) I'm not going to pull my hair out.
The crossover frequency has been set by the Ralph W crossover and I can understand what he's done. He has the AT170G0 that can be extended further than most 6.5" mid woofers due to it's great top end roll off behaviour and has matched that to the 27TFF which has a highish Fs. So he's using the capabilities of the mid woofer and keeping the tweeter well within it's range.
I've tried cutting back tweeters to get a closer centre but not worth the effort. The one in the pic is a 27TFFC with a 830875 Peerless HDS. Lucky I was still able to use the tweeter in another speaker as was paired with another smaller HDS driver.
The other easy option is to overlap drivers like the Dynaudio Audience 42 where the tweeter is rebated and the woofer isn't and have used that in a little Vifa P11 speaker.
One thing's for sure, I don't think Matt will be rebating the AT170G2 mid woofer due to the basket shape. HDS drivers are hard enough.
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Matt
The design is done and will get the drawing done in the next couple of days. It's 370 high x 220 wide x 284 deep outside using the thickness as suggested.
I'll send a PM with my email address so you can send me yours. That way I can send the drawing to you. The one that is posted here might be a bit small as there are size restrictions.
The design is done and will get the drawing done in the next couple of days. It's 370 high x 220 wide x 284 deep outside using the thickness as suggested.
I'll send a PM with my email address so you can send me yours. That way I can send the drawing to you. The one that is posted here might be a bit small as there are size restrictions.
Matt
Here's the drawing of the 14 litre vented. I decided not to do a hybrid box that can do a 10 litre sealed as well but this size would work for sealed. I had to reduce the size so I can add it to the post.
For anyone interested in a floorstander using the same design whilst the drivers were still available on ebay oz, 27 litres vented with a 76mm x 165 port gives an F3=45Hz. The same drawing can be used for width and depth but height and bracing would have to be changed to suit. The port would be about 35% of the box height from the floor.
Here's the drawing of the 14 litre vented. I decided not to do a hybrid box that can do a 10 litre sealed as well but this size would work for sealed. I had to reduce the size so I can add it to the post.
For anyone interested in a floorstander using the same design whilst the drivers were still available on ebay oz, 27 litres vented with a 76mm x 165 port gives an F3=45Hz. The same drawing can be used for width and depth but height and bracing would have to be changed to suit. The port would be about 35% of the box height from the floor.
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Rabbitz I see that you've not shown corner blocking and vertical bracing battens on the long sides of the box in the drawing, are these not needed given the small size of the box or have you treated this as a "Given"
That is a standard box treatment that Matt may not be aware of??
Matt my usual treatment of the dowel that Rabbitz has shown is to run a 40 X 19 hardwood brace from top to bottom of the side panels and then to run the brace from side to side using 40 X 19 again actually glued and screwed to the side braces, I also usually use small square blocks of MDF or hardwood quad to tie the corners together
Given the small size of the box it is probably overkill, but I'd be interested in your take on the side panel bracing Rabbitz.
Regards
Ted
That is a standard box treatment that Matt may not be aware of??
Matt my usual treatment of the dowel that Rabbitz has shown is to run a 40 X 19 hardwood brace from top to bottom of the side panels and then to run the brace from side to side using 40 X 19 again actually glued and screwed to the side braces, I also usually use small square blocks of MDF or hardwood quad to tie the corners together
Given the small size of the box it is probably overkill, but I'd be interested in your take on the side panel bracing Rabbitz.
Regards
Ted
Ted
It's not warranted in this design and is part of the decisions that we make to achieve a small size and suitable for intended use. Basically you don't want a panel larger than 400mm without some bracing or support. Each designer / builder finds what works for them.
There are several school of thoughts on box construction from built like a tank with the associated knuckle test plus hernia and lighter construction with selective bracing. Both methods can achieve good results. I've taken the path of lighter simple boxes with selective bracing. It's not the number of braces but the location to achieve the best results. For example, the cross brace position is located so the side panels are broken up into irrational numbers and will push resonances to higher frequencies where damping is effective. It's also in this location to allow placement of damping in the volume and away from the back wall. One of the most effective ways of doing a cross brace is to use the driver cutouts on the side wall at the cross brace junction.
I do use corner cleats but in larger designs such as floorstanders. I've never found vertical strips on the side panels to be effective and prefer horizontal strips placed at irrational locations (such as Phi and other strange numbers). There's a good section on it in the Loudspeaker Design Cookbook.
It's not warranted in this design and is part of the decisions that we make to achieve a small size and suitable for intended use. Basically you don't want a panel larger than 400mm without some bracing or support. Each designer / builder finds what works for them.
There are several school of thoughts on box construction from built like a tank with the associated knuckle test plus hernia and lighter construction with selective bracing. Both methods can achieve good results. I've taken the path of lighter simple boxes with selective bracing. It's not the number of braces but the location to achieve the best results. For example, the cross brace position is located so the side panels are broken up into irrational numbers and will push resonances to higher frequencies where damping is effective. It's also in this location to allow placement of damping in the volume and away from the back wall. One of the most effective ways of doing a cross brace is to use the driver cutouts on the side wall at the cross brace junction.
I do use corner cleats but in larger designs such as floorstanders. I've never found vertical strips on the side panels to be effective and prefer horizontal strips placed at irrational locations (such as Phi and other strange numbers). There's a good section on it in the Loudspeaker Design Cookbook.
Matt
To help visualise the damping I'm talking about I've added some pics of a speaker I'm just finishing that's a similar size.
This pic shows the felt type material that's used on the perimeter walls. The stuff I've used is actually an ironing board underlay but carpet underlay, shipping felt etc can be used. Just has to be porous and is glued on.
The cross brace is a handle from a lawn edger and you can use what you want and doesn't have to be round. I do prefer round for airflow and reflection reasons. If you use a rectangular piece, the narrow side is in the vertical direction.
The brace between the tweeter is hardwood (stable species like Tassie Oak) and this box has one under the woofer as well.
You can see the chamfer on the inside of the woofer hole and is there to provide better airflow for the woofer.
To help visualise the damping I'm talking about I've added some pics of a speaker I'm just finishing that's a similar size.
This pic shows the felt type material that's used on the perimeter walls. The stuff I've used is actually an ironing board underlay but carpet underlay, shipping felt etc can be used. Just has to be porous and is glued on.
The cross brace is a handle from a lawn edger and you can use what you want and doesn't have to be round. I do prefer round for airflow and reflection reasons. If you use a rectangular piece, the narrow side is in the vertical direction.
The brace between the tweeter is hardwood (stable species like Tassie Oak) and this box has one under the woofer as well.
You can see the chamfer on the inside of the woofer hole and is there to provide better airflow for the woofer.
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Next pic is the damping material that's in the volume of the box. It goes from the top back, between the brace and woofer and is folded to cover the bottom. The split at the top allows the port to poke through and damping has to be kept away from the port opening.
The stuff used here is from Jaycar and is a single piece but can be made with 2.
The stuff used here is from Jaycar and is a single piece but can be made with 2.
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Beware of the amount of quotes.
I'll take note of that for later (read: +10 years) use.
I don't understand the exact benefit of bracing, further then structural. I think I might get a hold/read up on a few loudspeaker books/websites.
For more extensive bracing I think I might leave that for a post-modification process... if need be.
That's gone on my library list!
Muchly appreciated!
Gotta have something like that laying around.
So what is the use of the 'floating' brace compared to the 'woofer/tweeter separation' brace?
I'm guessing the floating is just structual so the material + size isn't paramount to performance (so a thinner hardwood or MDF brace would do)?
Hand sanding that will be fun.
My jaycar shopping list is evergrowing.
In reference to the stuffing: I should fill it with as much as possible without interfering with the crossover, port and drivers?
Thanks again to both of you,
your combined knowledge not only compliments each other but is beneficial and just plain awesome and inspiring for an aspiring young audio enthusiast!
rabbitz said:
I'll take note of that for later (read: +10 years) use.
Unfortunately nothing's a given at the moment, but the design that rabbitz has given me all makes sense.Moondog55 said:
I don't understand the exact benefit of bracing, further then structural. I think I might get a hold/read up on a few loudspeaker books/websites.
For more extensive bracing I think I might leave that for a post-modification process... if need be.
rabbitz said:
That's gone on my library list!
rabbitz said:
Muchly appreciated!
rabbitz said:
Gotta have something like that laying around.
rabbitz said:
So what is the use of the 'floating' brace compared to the 'woofer/tweeter separation' brace?
I'm guessing the floating is just structual so the material + size isn't paramount to performance (so a thinner hardwood or MDF brace would do)?
rabbitz said:
Hand sanding that will be fun.
rabbitz said:
My jaycar shopping list is evergrowing.
In reference to the stuffing: I should fill it with as much as possible without interfering with the crossover, port and drivers?
Thanks again to both of you,
your combined knowledge not only compliments each other but is beneficial and just plain awesome and inspiring for an aspiring young audio enthusiast!
The cross brace is there to break up the side panels into smaller areas. If you have a large panel it resonates at a low frequency which can't be absorbed by the damping material so by breaking it into smaller sections you push the resonating frequency higher so it can be absorbed. Take for example Rolph Harris' wobble board (you may be too young to know him). As he moves the board it goes whoop whoop and if you made it half the size, the frequency would be higher.
The brace between the tweeter and woofer is purely structural as 2 holes have been made which weakens the baffle. It's there to provide a better foundation for the drivers.
Only the one layer of damping as shown. It comes as a sheet and just cut to size so it covers the bottom and goes to the top... sort of like a slanted "L". In vented boxes you don't use loose stuff like Dacron or pillow filling etc.
http://www1.jaycar.com.au/productView.asp?ID=AX3694&keywords=absorb&form=KEYWORD
The blue in the pic is the felt type material glued on the perimeter (top, bottom, sides) and the green is the damping material that's placed loose in the box. Boxes can be tuned with more or less damping but generally this scheme works fine.
As I said before Matt, this is a good thread to be part of. Maybe it should be renamed "Kit in Australia... what the heck, we'll start from scratch".
The brace between the tweeter and woofer is purely structural as 2 holes have been made which weakens the baffle. It's there to provide a better foundation for the drivers.
Only the one layer of damping as shown. It comes as a sheet and just cut to size so it covers the bottom and goes to the top... sort of like a slanted "L". In vented boxes you don't use loose stuff like Dacron or pillow filling etc.
http://www1.jaycar.com.au/productView.asp?ID=AX3694&keywords=absorb&form=KEYWORD
The blue in the pic is the felt type material glued on the perimeter (top, bottom, sides) and the green is the damping material that's placed loose in the box. Boxes can be tuned with more or less damping but generally this scheme works fine.
As I said before Matt, this is a good thread to be part of. Maybe it should be renamed "Kit in Australia... what the heck, we'll start from scratch".
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The Loudspeaker Design Cookbook by Vance Dickason is very good but it's a very hard slog at first. Once you've built a dozen speakers it falls into place.
Speaker Building 201 by Ray Alden is easier going and maybe better when starting but provides less information as you become more experienced. Nice section on example speakers.
Speaker Building 201 by Ray Alden is easier going and maybe better when starting but provides less information as you become more experienced. Nice section on example speakers.
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