More double 18's in progress.
- Thread starter Alan Sledzieski
- Start date
Re: More double 18's in progress.
Ivan,
Originally when I built the first set 2 years ago I had no Idea if the project would really work. So I built the box just as you see in this pic. Well I tried them and they put a big smaile on my face,along with the bands that I work with, so I just kept making them the same way. There are no rattles, hums, or funny sounds coming out of them, so I'm guessing they are solid enough. Unless you want to enlighten me on something that more bracing will do that I'm not hearing?
I have had some people ask me to build them a pair, but after I tell them the cost, ( mainly the cost of the 18's) they say well maybe not...
Ivan,
Originally when I built the first set 2 years ago I had no Idea if the project would really work. So I built the box just as you see in this pic. Well I tried them and they put a big smaile on my face,along with the bands that I work with, so I just kept making them the same way. There are no rattles, hums, or funny sounds coming out of them, so I'm guessing they are solid enough. Unless you want to enlighten me on something that more bracing will do that I'm not hearing?
I have had some people ask me to build them a pair, but after I tell them the cost, ( mainly the cost of the 18's) they say well maybe not...
Craig Hauber
Sophomore
Re: More double 18's in progress.
Looks good!
What are you loading them with and do you have any output measurements or comparisons to off-the-shelf products?
Looks good!
What are you loading them with and do you have any output measurements or comparisons to off-the-shelf products?
Silas Pradetto
Graduate Student
Re: More double 18's in progress.
More bracing = less panel flex. Less panel flex = more sound.
The ports look too small.
More bracing = less panel flex. Less panel flex = more sound.
The ports look too small.
Re: More double 18's in progress.
Faital pro 18 xl 1500.
Faital Pro 18XL1500 18" High Power Subwoofer Speakers - Faital Pro 18XL1500 18" for ported bass reflex subwoofer speaker cabinets. Lightweight neodymium magnet - Faital Pro 18XL1500 3000 watt high efficiency woofer with a high 98dB SPL for all high p
Measurements, well no scientific data, but my ears tell me there pretty darn good.
Faital pro 18 xl 1500.
Faital Pro 18XL1500 18" High Power Subwoofer Speakers - Faital Pro 18XL1500 18" for ported bass reflex subwoofer speaker cabinets. Lightweight neodymium magnet - Faital Pro 18XL1500 3000 watt high efficiency woofer with a high 98dB SPL for all high p
Measurements, well no scientific data, but my ears tell me there pretty darn good.
Re: More double 18's in progress.
Its not to small, as far as what the the program said. No port noise. 3 x 26.5 x 9'' deep
Its not to small, as far as what the the program said. No port noise. 3 x 26.5 x 9'' deep
Re: More double 18's in progress.
That's pretty small for a double 18... Hell, the port in my single 18 is almost 1.5x that size. Probably no port noise because it completely chokes off at high SPL.
I stopped listening to what the computer suggests a long time ago..
Evan
That's pretty small for a double 18... Hell, the port in my single 18 is almost 1.5x that size. Probably no port noise because it completely chokes off at high SPL.
I stopped listening to what the computer suggests a long time ago..Evan
Re: More double 18's in progress.
Alan, what Silas said.
I would run your current boxes, fairly hard, just with program music.
Feel the sides and back of the cabinet. If you can feel it moving, you are losing energy to cabinet flex.
This is energy that is not coming out as sound in the room.
Regards, Jack
Alan, what Silas said.
I would run your current boxes, fairly hard, just with program music.
Feel the sides and back of the cabinet. If you can feel it moving, you are losing energy to cabinet flex.
This is energy that is not coming out as sound in the room.
Regards, Jack
Re: More double 18's in progress.
I don't suggest "eyeballing" port sizes. Different manufacturers accentuate different parameters, so porting specs can vary wildly from brand to brand and model to model.
I think that the manufactures specs are the only way to go, unless you can measure the speakers in the cabinets yourself.
And then I would still be going by what I see on my computer screen, and enlisting its help.
Regards, Jack
That's pretty small for a double 18... Hell, the port in my single 18 is almost 1.5x that size. Probably no port noise because it completely chokes off at high SPL.
Evan
I don't suggest "eyeballing" port sizes. Different manufacturers accentuate different parameters, so porting specs can vary wildly from brand to brand and model to model.
I think that the manufactures specs are the only way to go, unless you can measure the speakers in the cabinets yourself.
And then I would still be going by what I see on my computer screen, and enlisting its help.
Regards, Jack
Re: More double 18's in progress.
As far as being small both 18's share the same box, unlike many other double 18's that are two seperate enclosures in cabinet
As far as port size, big small it doesn't really matter as long as you look at the port velocity, and tuning specs per the driver and box.
As far as cabinet flex, I'm sure you all are right. When I built the first set we compared them to yorkville double 18's, and a pair of eaw 528's, we went off our ear on what the jbl's sounded like as they were gone a long time ago. Put it this way, I got lucky, I'd like to set my subs up against the mentioned ones behind a black cloth and let you choose what you like the best. : )
Other issues I had when I first built them was pack size, along with me having to lift my mid high box on top of the dbl 18 myself, which was a jbl 4733, then a eaw la 325, and now my own home brew top box.
Wish I had some measuring devices, I'd like to compare a set of my dbl18's as is, compared to one with more bracing.
Something I have learned over the years. As far as being a weekend warrior, and not having to be rider friendly, along with just needing to fill areas less then lets say a stadium, or large venue where a professional company comes in is this. I would never buy a manufactured box again in my life, I would just build my own. Instead of paying for the name of the manufacture, the warranty, most of the time inferior components compaired to what I'm using. At least lets say compared to eaw and down, jbl and lower down the food chain. I'm not talking about Danley here and the upper lines, just the medium grade.
As far as being small both 18's share the same box, unlike many other double 18's that are two seperate enclosures in cabinet
As far as port size, big small it doesn't really matter as long as you look at the port velocity, and tuning specs per the driver and box.
As far as cabinet flex, I'm sure you all are right. When I built the first set we compared them to yorkville double 18's, and a pair of eaw 528's, we went off our ear on what the jbl's sounded like as they were gone a long time ago. Put it this way, I got lucky, I'd like to set my subs up against the mentioned ones behind a black cloth and let you choose what you like the best. : )
Other issues I had when I first built them was pack size, along with me having to lift my mid high box on top of the dbl 18 myself, which was a jbl 4733, then a eaw la 325, and now my own home brew top box.
Wish I had some measuring devices, I'd like to compare a set of my dbl18's as is, compared to one with more bracing.
Something I have learned over the years. As far as being a weekend warrior, and not having to be rider friendly, along with just needing to fill areas less then lets say a stadium, or large venue where a professional company comes in is this. I would never buy a manufactured box again in my life, I would just build my own. Instead of paying for the name of the manufacture, the warranty, most of the time inferior components compaired to what I'm using. At least lets say compared to eaw and down, jbl and lower down the food chain. I'm not talking about Danley here and the upper lines, just the medium grade.
Re: More double 18's in progress.
Typically a lot of number crunching on port size revolves around a figure of 2% of the speed of sound being a maximum port velocity. Adjust this to taste of course, and like others here, I typically enlarge the port by 30-50%.
And as you say, use all tools at your disposal, including your ears.
Best regards,
John
Typically a lot of number crunching on port size revolves around a figure of 2% of the speed of sound being a maximum port velocity. Adjust this to taste of course, and like others here, I typically enlarge the port by 30-50%.
And as you say, use all tools at your disposal, including your ears.
Best regards,
John
Silas Pradetto
Graduate Student
Re: More double 18's in progress.
There is absolutely zero difference in the math either way - if the port is split and the box volume is split, everything is exactly the same.
The advantage to a split box is if one driver fails, the other driver will not likely fail with it.
There is absolutely zero difference in the math either way - if the port is split and the box volume is split, everything is exactly the same.
The advantage to a split box is if one driver fails, the other driver will not likely fail with it.
Re: More double 18's in progress.
I did that, system impedence is off the wall, power handling is less at low freq also
I did that, system impedence is off the wall, power handling is less at low freq also
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Re: More double 18's in progress.
Silas, I did what you said about cutting things in half, all hell broke loose.
Mine is red yours is green
Silas, I did what you said about cutting things in half, all hell broke loose.
Mine is red yours is green
Silas Pradetto
Graduate Student
Re: More double 18's in progress.
One driver in a box half the volume with half the port area should be identical to two drivers in the box (with double the volume and port area of the single driver box). I'd simulate it but there's no Bassbox on this shop computer.
Also - recall that a single driver handles half the power and has double the impedance - you need to correct your input numbers as such - it looks like you're simply applying the same power to the single driver box - and it should be half that.
Also version 2 - have you ever measured Fb of a completed sub? The calculation is usually quite far off from reality.
One driver in a box half the volume with half the port area should be identical to two drivers in the box (with double the volume and port area of the single driver box). I'd simulate it but there's no Bassbox on this shop computer.
Also - recall that a single driver handles half the power and has double the impedance - you need to correct your input numbers as such - it looks like you're simply applying the same power to the single driver box - and it should be half that.
Also version 2 - have you ever measured Fb of a completed sub? The calculation is usually quite far off from reality.
Re: More double 18's in progress.
Hey Alan, not sure if thsi would be any quicker for you, but you can press ALT and the PRTSCN (printscreen) key to get a screen capture of whatever screen is active on your computer.
Paste (control V) and Save it into a simple program like paint,upload those pictures and it'll avoid you having to take a picture of your computer screen, and it will be way clearer...
SP
Hey Alan, not sure if thsi would be any quicker for you, but you can press ALT and the PRTSCN (printscreen) key to get a screen capture of whatever screen is active on your computer.
Paste (control V) and Save it into a simple program like paint,upload those pictures and it'll avoid you having to take a picture of your computer screen, and it will be way clearer...
SP
Re: More double 18's in progress.
Opps, ya I didn't change the power, but even after changing power, the system impedence stays way off, power handling is lower at lower freq's with the single box also, box frequency is still different
Opps, ya I didn't change the power, but even after changing power, the system impedence stays way off, power handling is lower at lower freq's with the single box also, box frequency is still different