Hi
I believe a few guys here are building this, and so am I.
My drivers and the better crossover parts (Goertz 14 AWG foil, Solen caps, Eagle films - all the series components) are reaching me early next week or today, so I shold start briefing woodworkers early next week.
A few Qs on cabinets, stands and ports, would be great if someone helps me out here. Thanks in Advance.
1. Box volume: How tolerant is the design to small changes in internal volume? Since the woodworking is local (shipping to India is killing) and my brief to the woodworker will be to use corner and front to back bracing above woofer, which will probably kill a bit of internal volume. I will increase the dimensions to compensate, but may go slightly off - how big of a problem is it?
2. Stuffing and damping: I don't have Sonic Barrier, Whispermat etc. available, so will be using local substitutes, someone help me with making a choice:
a. Car carpet (difficult to get but can try)
b. Generic yellow bedding foam
c. Recron - the Indian substitute to Dacron
d. Coir
3. Ports: I may not be able to get the exact port tube of 1.6" internal width. In which case I will need to plug the box dimensions to the closest I know, along with the T/S (I'll be using Zaph's average of two units, not manufacturer specs as I can't measure them myself) into WinISD to get a port length to find the length I'll need to tune the box to the 42 Hz required. Is this acceptable as a procedure?
Staying on ports, what would be a minimum acceptable width? I thought 1" would be way too small, and 3" too wide. Is there some way to determine port width WRT box/woofer size or air velocity?
4. Cabinet material: I will probably be using plywood and not MDF (easier to get). The stuff varies greatly in quality, so I'll have to figure a way to get good quality board. I may have to use 1" ply throughout, buying just one 4/8 sheet. Apart from increasing all external dimension by half an inch, anything else to watch out for? Like what glues, type of joints etc. should be used?
5. Stands: The application is for nearfield monitoring from my DAW at my home studio. I was thinking of buying a couple of inexpensive barstools and setting them up for the time being, and later figure out how to make the stands. Which is where I need the most help. I have no idea on how to make a good stand. Any pointers, link would help, as I have never used standmounts before.
I was thinking sand-filled PVC pipe with MDF platforms on top and bottom (absorbent), or a complete cast iron structure spiked to the floor (transmittive), or a combination (MDF platforms/cast iron rods or Cast iron plates/sand-filled pipe)... Which way to go?
Boy, this is surely my last try to get things from USA by courier. The delivery is quick, but $200 is what you should be prepared to spend, over and above the cost. $80 shipping, $120 tax.
This thing had better be beating some high-dollar designs, which I am pretty sure it will do.
Thanks again.
I believe a few guys here are building this, and so am I.
My drivers and the better crossover parts (Goertz 14 AWG foil, Solen caps, Eagle films - all the series components) are reaching me early next week or today, so I shold start briefing woodworkers early next week.
A few Qs on cabinets, stands and ports, would be great if someone helps me out here. Thanks in Advance.
1. Box volume: How tolerant is the design to small changes in internal volume? Since the woodworking is local (shipping to India is killing) and my brief to the woodworker will be to use corner and front to back bracing above woofer, which will probably kill a bit of internal volume. I will increase the dimensions to compensate, but may go slightly off - how big of a problem is it?
2. Stuffing and damping: I don't have Sonic Barrier, Whispermat etc. available, so will be using local substitutes, someone help me with making a choice:
a. Car carpet (difficult to get but can try)
b. Generic yellow bedding foam
c. Recron - the Indian substitute to Dacron
d. Coir
3. Ports: I may not be able to get the exact port tube of 1.6" internal width. In which case I will need to plug the box dimensions to the closest I know, along with the T/S (I'll be using Zaph's average of two units, not manufacturer specs as I can't measure them myself) into WinISD to get a port length to find the length I'll need to tune the box to the 42 Hz required. Is this acceptable as a procedure?
Staying on ports, what would be a minimum acceptable width? I thought 1" would be way too small, and 3" too wide. Is there some way to determine port width WRT box/woofer size or air velocity?
4. Cabinet material: I will probably be using plywood and not MDF (easier to get). The stuff varies greatly in quality, so I'll have to figure a way to get good quality board. I may have to use 1" ply throughout, buying just one 4/8 sheet. Apart from increasing all external dimension by half an inch, anything else to watch out for? Like what glues, type of joints etc. should be used?
5. Stands: The application is for nearfield monitoring from my DAW at my home studio. I was thinking of buying a couple of inexpensive barstools and setting them up for the time being, and later figure out how to make the stands. Which is where I need the most help. I have no idea on how to make a good stand. Any pointers, link would help, as I have never used standmounts before.
I was thinking sand-filled PVC pipe with MDF platforms on top and bottom (absorbent), or a complete cast iron structure spiked to the floor (transmittive), or a combination (MDF platforms/cast iron rods or Cast iron plates/sand-filled pipe)... Which way to go?
Boy, this is surely my last try to get things from USA by courier. The delivery is quick, but $200 is what you should be prepared to spend, over and above the cost. $80 shipping, $120 tax.
This thing had better be beating some high-dollar designs, which I am pretty sure it will do.Thanks again.
I don't see anyone helping you, so I'll just put out a few quick answers.
1. Not too critical but be sure to err on the larger side. Also be willing and able to adjust the port length to maintain tuning.
2. It's difficult to judge the consistency and effectiveness of any of those items. Dacron can work, but due to it's fluffy consistency, it's difficult to arrange in a vented enclosure so that the middle of the cabinet can remain open. If you can get it in denser sheet format that would be fine. Otherwise, consider 1/2" carpet padding, doubled up to 1" thick on all internal sides. This stuff is also variable in consistency. Your best bet is to search out items with proven acoustic properties from vendors who supply that type of thing. Good luck.
3. If you are not using a flared port, use roughly 50mm inside diamater and calculate a new length using WinISD. Anything much larger than that will not fit in the box, and anything smaller than that without a flare will have turbulence noise.
4. Plywood is fine, as long as it's void-free. Leave it to your woodworker for figuring out the corner types.
5. Stand construction is not critical. The issue bigger than mass, damping, coupling and all that is tip-over stability and speaker location. These need to be out from the walls a bit and the tweeters need to be at ear level. You mention these are for near field listening, however I hope they are still at least a meter away from your ears. Anything closer than that will make them sound a little on the warm side, along with some integration and imaging issues. These are not nearfield speakers by design, but should work fine at least a meter away.
I almost regret posting my designs for fear that the design will not be liked, the expectations are too high, or the pain in building your own speaker is too much. (among other things) So, I hope it works out for you. If you have more questions, I'll let others answer them. I'm a little busy and won't be back to this forum for some time.
1. Not too critical but be sure to err on the larger side. Also be willing and able to adjust the port length to maintain tuning.
2. It's difficult to judge the consistency and effectiveness of any of those items. Dacron can work, but due to it's fluffy consistency, it's difficult to arrange in a vented enclosure so that the middle of the cabinet can remain open. If you can get it in denser sheet format that would be fine. Otherwise, consider 1/2" carpet padding, doubled up to 1" thick on all internal sides. This stuff is also variable in consistency. Your best bet is to search out items with proven acoustic properties from vendors who supply that type of thing. Good luck.
3. If you are not using a flared port, use roughly 50mm inside diamater and calculate a new length using WinISD. Anything much larger than that will not fit in the box, and anything smaller than that without a flare will have turbulence noise.
4. Plywood is fine, as long as it's void-free. Leave it to your woodworker for figuring out the corner types.
5. Stand construction is not critical. The issue bigger than mass, damping, coupling and all that is tip-over stability and speaker location. These need to be out from the walls a bit and the tweeters need to be at ear level. You mention these are for near field listening, however I hope they are still at least a meter away from your ears. Anything closer than that will make them sound a little on the warm side, along with some integration and imaging issues. These are not nearfield speakers by design, but should work fine at least a meter away.
sangram said:
I almost regret posting my designs for fear that the design will not be liked, the expectations are too high, or the pain in building your own speaker is too much. (among other things) So, I hope it works out for you. If you have more questions, I'll let others answer them. I'm a little busy and won't be back to this forum for some time.
Hi,
You say the application is nearfield monitoring, the design as is is not suitable.
From Zaphs article. This is what you need for genuine nearfield.
Dense padding (carpet type) etc... up to 1cm thick works best as
the first layer lining a wall, but its optional. To get vented boxes
working well the box walls should be lined with open cell foam
2cm to 3cm thick. In the tall thin box types you can add dacron /
BAF/Polyfill or similar to the airspace that is well way from the port.
There are two schools of thought with stands.
Lightwieght and rigid and massive and rigid.
Either works well IMO, I'd go all steel and simply copy a manafacturers product.
http://www.millennium-music.co.uk/home/products.pl?ProductCode=QLBS336&mode=detail
Is a nearfield stand.
/sreten.
You say the application is nearfield monitoring, the design as is is not suitable.
From Zaphs article. This is what you need for genuine nearfield.
Dense padding (carpet type) etc... up to 1cm thick works best as
the first layer lining a wall, but its optional. To get vented boxes
working well the box walls should be lined with open cell foam
2cm to 3cm thick. In the tall thin box types you can add dacron /
BAF/Polyfill or similar to the airspace that is well way from the port.
There are two schools of thought with stands.
Lightwieght and rigid and massive and rigid.
Either works well IMO, I'd go all steel and simply copy a manafacturers product.
http://www.millennium-music.co.uk/home/products.pl?ProductCode=QLBS336&mode=detail
An externally hosted image should be here but it was not working when we last tested it.
Is a nearfield stand.
/sreten.
Hi Zaph, sreten,
Great, that's all I was looking forward to hearing. The baffle will also become a bit larger. I'm using 1" wood through and through, and trying not to have two sides of the same size. So almost all sides add 1/2", and the depth 1/4" more than the PE box, the volume also goes up a bit.
Thanks, don't have those kind of vendors, but after reading sreten's post below, will be using open cell yellow foam. Think that should work out OK, or try for carpet padding.
Just the answer I was looking for. I'll probably get someone to machine a 45-50 mm flare into the back panel and cut a tube to the length.
Done, except if I leave to them they will just not do anything apart from regular glue. So maybe I'll specify corner braces and front-to back and side to side bracing.
I'll be about a meter away, just about. I guess I should have asked before I built. We'll see, or build another pair later for nearfield, or change the lowpass to suit.
OK I had typed a really long reply to this.
That comment was directed at the frustration of paying almost double the original unit prices to get the units into the country. It had nothing to do with the design and whether the design was worth it.
I know you're probably not around to read this, but FWIW I really enjoy reading your pages, I think your designs are fantastic, and you're doing a great job for all of us in this little DIY community.
I for one would be really disappointed if this flow of info stopped, and would kick myself comatose if I felt my misplaced comment had anything to do with it. My apologies.
I don't think you quite realise how much it means to hear from you directly, Zaph, and how much more confident of my success this reply makes me. Thanks again.
Great, I can't see a way of emailing Zaph, but I seem to remember the crossover seemed have a 1.5 mH inductor instead of 2.2 mH on the woofer. Can't remember much else.
Edit: Forget it, I found the crossover on one of Zaph's earlier posts, the L-pad is also different, 3.3 and 5 ohms instead of 4 and 3.3 ohms. Maybe I'll try both.
Awesome, I'll use up the surplus 2" foam sheet I have with me. And a layer of closed cell padding foam for the first layer.
Looks nice, and not too complex to make using steel rods and x-sections. I'll see what I can do.
Thanks a ton for the help!
Zaph said:
Great, that's all I was looking forward to hearing. The baffle will also become a bit larger. I'm using 1" wood through and through, and trying not to have two sides of the same size. So almost all sides add 1/2", and the depth 1/4" more than the PE box, the volume also goes up a bit.
Zaph said:
Thanks, don't have those kind of vendors, but after reading sreten's post below, will be using open cell yellow foam. Think that should work out OK, or try for carpet padding.
Zaph said:
Just the answer I was looking for. I'll probably get someone to machine a 45-50 mm flare into the back panel and cut a tube to the length.
Zaph said:
Done, except if I leave to them they will just not do anything apart from regular glue. So maybe I'll specify corner braces and front-to back and side to side bracing.
Zaph said:
I'll be about a meter away, just about. I guess I should have asked before I built. We'll see, or build another pair later for nearfield, or change the lowpass to suit.
Zaph said:
OK I had typed a really long reply to this.
That comment was directed at the frustration of paying almost double the original unit prices to get the units into the country. It had nothing to do with the design and whether the design was worth it.
I know you're probably not around to read this, but FWIW I really enjoy reading your pages, I think your designs are fantastic, and you're doing a great job for all of us in this little DIY community.
I for one would be really disappointed if this flow of info stopped, and would kick myself comatose if I felt my misplaced comment had anything to do with it. My apologies.
I don't think you quite realise how much it means to hear from you directly, Zaph, and how much more confident of my success this reply makes me. Thanks again.
sreten said:
Great, I can't see a way of emailing Zaph, but I seem to remember the crossover seemed have a 1.5 mH inductor instead of 2.2 mH on the woofer. Can't remember much else.
Edit: Forget it, I found the crossover on one of Zaph's earlier posts, the L-pad is also different, 3.3 and 5 ohms instead of 4 and 3.3 ohms. Maybe I'll try both.
sreten said:
Awesome, I'll use up the surplus 2" foam sheet I have with me. And a layer of closed cell padding foam for the first layer.
sreten said:There are two schools of thought with stands.
Lightwieght and rigid and massive and rigid.
Either works well IMO, I'd go all steel and simply copy a manafacturers product.
http://www.millennium-music.co.uk/home/products.pl?ProductCode=QLBS336&mode=detail
Is a nearfield stand.
Looks nice, and not too complex to make using steel rods and x-sections. I'll see what I can do.
Thanks a ton for the help!
Hi,
I would not use closed cell foam padding for the first layer,
it will reduce internal volume too much for little effect.
The first layer (up to 1cm) can be dense, but not closed cell.
Note that you can obviously EQ the baffle step, but building
with lower BSC gives you a liitle more monitoring headroom.
:0/sreten.
I would not use closed cell foam padding for the first layer,
it will reduce internal volume too much for little effect.
The first layer (up to 1cm) can be dense, but not closed cell.
Note that you can obviously EQ the baffle step, but building
with lower BSC gives you a liitle more monitoring headroom.
:0/sreten.
Hi,
I thought even the dense carpet padding would reduce the volume by a similar amount, maybe I could use a dense open-cell foam - if I can find it.
Thanks, I didn't remember about EQ, as I'm a bit of a snob about it. Maybe I'll put in these inductors (almost as expensive as the tweeters!!!) for now and bundle the reduced BSC components with my next speaker purchase, as I'm beginning to feel I should've gotten that crossover to start with.
Thanks sreten for your help. I look forward to a long and happy build.
I thought even the dense carpet padding would reduce the volume by a similar amount, maybe I could use a dense open-cell foam - if I can find it.
Thanks, I didn't remember about EQ, as I'm a bit of a snob about it. Maybe I'll put in these inductors (almost as expensive as the tweeters!!!) for now and bundle the reduced BSC components with my next speaker purchase, as I'm beginning to feel I should've gotten that crossover to start with.
Thanks sreten for your help. I look forward to a long and happy build.
"I'll probably get someone to machine a 45-50 mm flare into the back panel and cut a tube to the length."
Ideally the end of the port inside the box would terminate with a small piece of wood so that it could be similarly flared.
Not only will there be less chance of port noise, but the air will flow easier in one direction than the other, with the possibility of the driver's center position getting offset, reducing effective xmax.
Ideally the end of the port inside the box would terminate with a small piece of wood so that it could be similarly flared.
Not only will there be less chance of port noise, but the air will flow easier in one direction than the other, with the possibility of the driver's center position getting offset, reducing effective xmax.
Sangram, hello!
Im assuming you have now finished your speakers.
I am just starting (already got the parts and MDF boards).
Im paying a store with programable automatic routing and cutting machine to make the cuts for me.
Im following the exact directions of Zaph regarding desing and even using the same components. However i have a question about port location (Zaph says "I placed the port behind the tweeter"). Should i place the port exactly behind the tweeter: same height and left-right location, or should i just place it centered at tweeters level??
Know you finally have them, what are your impressions on this monitors?
Thanks in advance
Best regards.
Im assuming you have now finished your speakers.
I am just starting (already got the parts and MDF boards).
Im paying a store with programable automatic routing and cutting machine to make the cuts for me.
Im following the exact directions of Zaph regarding desing and even using the same components. However i have a question about port location (Zaph says "I placed the port behind the tweeter"). Should i place the port exactly behind the tweeter: same height and left-right location, or should i just place it centered at tweeters level??
Know you finally have them, what are your impressions on this monitors?
Thanks in advance
Best regards.
You must be joking, right?
The planning for the woodwork is going on right now, so no, my speakers aren't complete.
I envy you guys who have access to automatic routing machines and such.
The way we work is we get the boxes produced by professional carpenters (who use hand tools). As of now I haven't managed to find anyone who I can trust with a wardrobe - let alone this project.
But I'll get it done.
I'm sorry I don't have a better answer on my impressions on anything except that those woofer can move some serious air (some free air break-in).
On the port location, I am planning on the side opposite the tweeter actually, but I'm not sure that it's life-and-death critical. Zaph had replied to someone on another forum (who put the port in front, no less) that it was probably OK in most locations. As long as you don't put it directly behind the woofer, I guess it would be OK.
The planning for the woodwork is going on right now, so no, my speakers aren't complete.
I envy you guys who have access to automatic routing machines and such.
The way we work is we get the boxes produced by professional carpenters (who use hand tools). As of now I haven't managed to find anyone who I can trust with a wardrobe - let alone this project.
But I'll get it done.
I'm sorry I don't have a better answer on my impressions on anything except that those woofer can move some serious air (some free air break-in).
On the port location, I am planning on the side opposite the tweeter actually, but I'm not sure that it's life-and-death critical. Zaph had replied to someone on another forum (who put the port in front, no less) that it was probably OK in most locations. As long as you don't put it directly behind the woofer, I guess it would be OK.
Im sorry i didnt see the "post date" i thought you had posted a few months ago...
Im in a sort of "intermediate situation" here. On one side i have automated routing / cutting avaible for about 90 USD including MDF and the cuts. But on the other side i there are NO supply speaker drivers/component supply stores. I have to orther everything from Madisound - Partsexpress, and costs can get quite prohibited if you include shipping and local taxes. I payed about 390 USD for the drivers alone!!!!
I have no money left right now so ill have to wait a month or two to get the cross over parts...
Good luck with the project. I hope we exchange some pictures and comments, when we finally manage build them.
Regards!
Im in a sort of "intermediate situation" here. On one side i have automated routing / cutting avaible for about 90 USD including MDF and the cuts. But on the other side i there are NO supply speaker drivers/component supply stores. I have to orther everything from Madisound - Partsexpress, and costs can get quite prohibited if you include shipping and local taxes. I payed about 390 USD for the drivers alone!!!!
I have no money left right now so ill have to wait a month or two to get the cross over parts...
Good luck with the project. I hope we exchange some pictures and comments, when we finally manage build them.
Regards!
JBL practical guides always pointed out that a port should be located at a distance at least twice its diametre from the nearest boundary, in order to work fully well. Also no damping material should be located in such a vicinity. Hope this helps. Some speaker box software can predict best location for transmitting minimum box resonances to the outside. But this is largely irrelevant in your case since a back port will make inbox nasties, that make it out through it, largely attenuated towards the listening space since there is a long path to the front, and the range they occur in a small box is relatively high and directional enough.
salas said:
Here's an interesting example of such an approach:
http://audioclone.free.fr/BIG BABY.gif
richardtextex said:...
Good luck with the project. I hope we exchange some pictures and comments, when we finally manage build them.
Regards!
Of course we should exchange notes.
Actually my situation is worse, because I too had to import drivers and the better crossover parts from Madisound, and I paid US$460 equivalent for the drivers, the parts, shipping and customs (40% duty). But that's OK, because I think that this is going to beat anything commercial at twice the price available in the country - even finished speakers are very expensive due to the high customs rates.
I am looking at getting a box made from 3/4 inch plywood all the way round, with a 5mm black glass epoxied on the front baffle, that way I can avoid the rebate for the drivers as that tends to be very inaccurate when being done by hand - and get some isolation between the drivers and the baffle. Planning bracing in the BBC style, which I've seen on some old speakers (using battens for all panel joints), and a cherry or rosewood veneer. Sounds like a lot of effort, so let's see.
salas - many thanks for the info on the port, which probably means it needs to be mounted near the top of the woofer area, but since midrange leakage will be low it should not be too much of a problem. Just don't want to get any part of the woofer backwave to go into free air, so in a small box like this I'll have to figure out some other solution (maybe a Polk power-port?)
salas said:
Which is almost I had planned, putting it at the back on the side opposite the tweeter, so technically not behind the tweeter, as I might later choose to put a box behind the tweeter.
My biggest problem right now is the driver countersink, being so inaccurate with hand tools my only recourse is to use a second layer of veneer/glass/aluminium over the wood so the drivers appear to be countersunk. Of course that means the tweeter will need a layer of some material below it, usually closed foam, and then it may vibrate due to loose coupling to the baffle...
Now you see why it's taking me so long?
sangram said:
Hi,
Not any BBC style I'm aware of. BBC style is no bracing and thin
plywood panels for the walls critically damped with bitumen pads.
Due to the thinness of the walls battens have to be used.
Also note Zaph uses a prebuilt cabinet - there is no reason to
exactly copy the bass alignment - you can design your own.
/sreten.
Sorry, yes, battens is what I meant. I had seen this used on old Philips speakers but those were made of particle board, not plywood, and not that thin either - plus front to back and top to bottom braces (not shelves). Not sure of how the cookie will crumble though, as it all depends on the woodworker's skills.
Zaph had replied that baffle dimensions need to be preserved for the baffle step to work correctly, so I am planning to stay with that.
The L18 modelled in that looks good and I'm not really that keen to experiment, though again he has mentioned it's possible to vary the enclosure depth.
I don't have that much appetite for experimentation in speaker building actually, I prefer experimenting with electronics. For speakers I stay store-bought or very simple designs like this one. As a matter of fact it's my first serious speaker building project since the old days where I would take a random woofer, a random tweeter, stick them into a random box with a random crossover (bought off the shelf) and still liking the sound, because I had built it. But I digress.
Zaph had replied that baffle dimensions need to be preserved for the baffle step to work correctly, so I am planning to stay with that.
The L18 modelled in that looks good and I'm not really that keen to experiment, though again he has mentioned it's possible to vary the enclosure depth.
I don't have that much appetite for experimentation in speaker building actually, I prefer experimenting with electronics. For speakers I stay store-bought or very simple designs like this one. As a matter of fact it's my first serious speaker building project since the old days where I would take a random woofer, a random tweeter, stick them into a random box with a random crossover (bought off the shelf) and still liking the sound, because I had built it. But I digress.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.