I have a generic 8inch sub that is just sitting around and I thought i would attempt to make a transmission line box for it. Shold i try making a folded horn or just a regular transmission line? It would be going into a car so it can be fregirator sized... It would also be receiving its rated power whatever I put it in (70 watts continuous).
Also I searched but I couldn't really find a formula or way to decide on how to design the box. It would be helpful to have 😎.
Also I searched but I couldn't really find a formula or way to decide on how to design the box. It would be helpful to have 😎.
Formula for short transmission line:
Length = quarter wavelength of fs
Start area of line = 2*Sd
End area of line = Sd
If your crossover point is high, you should use some stuffing/insulation inside the line and make the line a little bit shorter.
Folded horns for car use: works very well if you have enough free space, but sounds awful in a small trunk. That is my subjective point of wiev, but you should try it out anyway cause it may give you a good time🙂
Nice project Nuuk!
I'm soon finished with a pair of TL boxes for the Fane Crescendo 15MB. This is the first TL boxes of mine, so I look forward to hear the results in a few days.
Length = quarter wavelength of fs
Start area of line = 2*Sd
End area of line = Sd
If your crossover point is high, you should use some stuffing/insulation inside the line and make the line a little bit shorter.
Folded horns for car use: works very well if you have enough free space, but sounds awful in a small trunk. That is my subjective point of wiev, but you should try it out anyway cause it may give you a good time🙂
Nice project Nuuk!
I'm soon finished with a pair of TL boxes for the Fane Crescendo 15MB. This is the first TL boxes of mine, so I look forward to hear the results in a few days.
You might be able to use my AutoTuba design, but the driver requirements are fairly restrictive. I'd have to know the T/s specs to know if it would work for you.
Would a folded horn be a better choice. I'm thinking of buying a JL 8inch W0 woofer or a inexpensive peerless (I would probobly try the woofer I have right now and buy one of the two I mentioned if I didnt like it). Also what is the formula or way to figure out how to make a folded horn box?
So far From what I understand a transmission line box can play low but not that much louder then a regular sealed or ported box and, a folded horn box can play extremely loud with minimal power (sounds like a better goal to me). Please correct me if I'm wrong on this. 🙂
Thanks for the help from everyone so far
So far From what I understand a transmission line box can play low but not that much louder then a regular sealed or ported box and, a folded horn box can play extremely loud with minimal power (sounds like a better goal to me). Please correct me if I'm wrong on this. 🙂
Thanks for the help from everyone so far
A horn should be more efficient than a TL box, and have better transient response. But you have to follow the guidelines of physics during the design. A basshorn should never be shorter than two meters (around 40 Hz cutoff), four meter or longer horns should be considered. In most cases a properly designed horn is to big for the room or car. Then a TL box can be a good choice.
So if I wanted to make a horn with a 40 hz cutoff frequency it would automatically be 2 meters long about, or is there more to it?
I was searching and found this website on horns: http://melhuish.org/audio/horndesign.html
I did all of the calculations but I'm confused on how to put it all togethor (how to use those calculations to make the actual dimensions). 😕
Sorry for asking all of these questions but I really want to make either a Folded horn or TL enclosure. Thanks
I was searching and found this website on horns: http://melhuish.org/audio/horndesign.html
I did all of the calculations but I'm confused on how to put it all togethor (how to use those calculations to make the actual dimensions). 😕
Sorry for asking all of these questions but I really want to make either a Folded horn or TL enclosure. Thanks
Yes, you need 2 meters, but there's a lot more to it than just that. A horn is probably not the best idea for one's first foray into speaker design. I built quite a few Altec, Jensen and Klipsch clones before I learned enough about the beasts to roll my own.
Like BillFitzmaurice says, there is a little bit more to it than 2 meters, but if you download McBeans hornresponse analysis program http://www.users.bigpond.com/dmcbean/ everything should come easily after a few days testing.
Remember to check the help text each time you meet a problem.
Still there is a problem to transform your calculations into actual dimensions if you're not familiar with a CAD program. McBean revolves the horn curve around one axis, so you will always make a radial horn. There is not a big problem to transform a radial basshorn to an easier to build format, but it is much easier with a CAD program.
I can run a calculation if you give me this information:
1. What are the Small & Thiele parameters on the driver you're going to use?
2. How low do you want your horn to play?
Remember to check the help text each time you meet a problem.
Still there is a problem to transform your calculations into actual dimensions if you're not familiar with a CAD program. McBean revolves the horn curve around one axis, so you will always make a radial horn. There is not a big problem to transform a radial basshorn to an easier to build format, but it is much easier with a CAD program.
I can run a calculation if you give me this information:
1. What are the Small & Thiele parameters on the driver you're going to use?
2. How low do you want your horn to play?
1. What are the Small & Thiele parameters on the driver you're going to use?
2. How low do you want your horn to play?
I think I would like to use a JL W0-8. FS 31.9 hz, Qes .447, Qts .426, Qms 9.029, Vas 1.02 sq feet (28.9 litres), Xmax (one way) 6.8, SPL 85, SD 33.8 inch sq. , RE 3.30 Ohms, nominal impdence 4 ohms, power handling continuous 75,
driver displacement .023 litres ft 3.
35 hertz is probobly the lowest bass I would play through it.
I did do some of the calculations (tuned to 40 hz I think):
Throat Area .247 (m2)
Compression chamber .34 (m2 I think...) I used another formula and got .50 instead.
L1= 3.26875 (inches)
L2= 4.225 (inches again)
I couldn't figure out what AT was in this calculation: LT= At/box height
I tryed another formula to get the slant angle but again i Don't know if its even close... 1.67 * woofers SD= 56 degrees.
If you have time could you also run calculations on this dayton driver also? I would also like it to play to 35 or 38 hz (unless the box is going to fridgerator sized for that low of a frequency). Here are the parameters for it Specifications:
*Power Handling: 80 watts RMS/120 watts max *VCdia: 1.5" *Le: 1.2 mH *Impedance: 8 ohms per coil *Re: 3.00 ohms *Frequency range: 30-2,000 Hz *Fs: 28 Hz *SPL: 89.0 dB 2.83V/1m *Vas: 1.40 cu. ft. *Qms: 3.40 *Qes: .47 *Qts: .41 *Xmax: 6 mm *Dimensions: Overall Diameter: 8-1/2", Cutout Diameter: 7-1/8", Mounting Depth: 4-1/4".
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-480 (there is a PDF on this page with more parameters if needed).
I used this thread on the sounddomain forum : http://forum.sounddomain.com/ubb/ultimatebb.php?ubb=get_topic;f=11;t=070826;p=3
and this website on horns for compression chamber and throat area: http://melhuish.org/audio/horndesign.html
So am I even close on any of these? lol
Thank you very much 🙂
2. How low do you want your horn to play?
I think I would like to use a JL W0-8. FS 31.9 hz, Qes .447, Qts .426, Qms 9.029, Vas 1.02 sq feet (28.9 litres), Xmax (one way) 6.8, SPL 85, SD 33.8 inch sq. , RE 3.30 Ohms, nominal impdence 4 ohms, power handling continuous 75,
driver displacement .023 litres ft 3.
35 hertz is probobly the lowest bass I would play through it.
I did do some of the calculations (tuned to 40 hz I think):
Throat Area .247 (m2)
Compression chamber .34 (m2 I think...) I used another formula and got .50 instead.
L1= 3.26875 (inches)
L2= 4.225 (inches again)
I couldn't figure out what AT was in this calculation: LT= At/box height
I tryed another formula to get the slant angle but again i Don't know if its even close... 1.67 * woofers SD= 56 degrees.
If you have time could you also run calculations on this dayton driver also? I would also like it to play to 35 or 38 hz (unless the box is going to fridgerator sized for that low of a frequency). Here are the parameters for it Specifications:
*Power Handling: 80 watts RMS/120 watts max *VCdia: 1.5" *Le: 1.2 mH *Impedance: 8 ohms per coil *Re: 3.00 ohms *Frequency range: 30-2,000 Hz *Fs: 28 Hz *SPL: 89.0 dB 2.83V/1m *Vas: 1.40 cu. ft. *Qms: 3.40 *Qes: .47 *Qts: .41 *Xmax: 6 mm *Dimensions: Overall Diameter: 8-1/2", Cutout Diameter: 7-1/8", Mounting Depth: 4-1/4".
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-480 (there is a PDF on this page with more parameters if needed).
I used this thread on the sounddomain forum : http://forum.sounddomain.com/ubb/ultimatebb.php?ubb=get_topic;f=11;t=070826;p=3
and this website on horns for compression chamber and throat area: http://melhuish.org/audio/horndesign.html
So am I even close on any of these? lol
Thank you very much 🙂
Hi, and sorry for my slow answer.
Drivers with high QTS (weak motor system) does not play well in regular horn designs.
If you're going to build your horns with rear chamber and front compression chamber, try to follow these three rules:
1. Lower QTS than 0,3
2. Higher BL than 20
3. Small Xmax (then the horn will be more linear when you play at higher sound levels).
I would have to say that the two drivers you choosed have quite the opposite parameters, never the less it is possible to make an unusual horn for them which will make them sound great. But they may be a little bit big.
Hope you still want to build a horn....
I'm not done with the calculations yet, but I'll post the results as soon as I'm finished.
Drivers with high QTS (weak motor system) does not play well in regular horn designs.
If you're going to build your horns with rear chamber and front compression chamber, try to follow these three rules:
1. Lower QTS than 0,3
2. Higher BL than 20
3. Small Xmax (then the horn will be more linear when you play at higher sound levels).
I would have to say that the two drivers you choosed have quite the opposite parameters, never the less it is possible to make an unusual horn for them which will make them sound great. But they may be a little bit big.
Hope you still want to build a horn....
I'm not done with the calculations yet, but I'll post the results as soon as I'm finished.
Thank you for doing those calculations for me. I'm if I have wasted your time with those. I decided I would use a JL W0 8 inch sub and just use a transmission line enclosure (close to one anyways) instead. I'm almost done building it and here is a post I did about it on another forum:
http://www.the12volt.com/installbay/forum_posts.asp?TID=48412&PN=1&TPN=1
http://www.the12volt.com/installbay/forum_posts.asp?TID=48412&PN=1&TPN=1
I finished building it this weekend. It sounds great and can get pretty loud. I'm using an 8 inch JL W0 and the frequency it's tuned to I guess you could say, is 40 hz. A big thanks to everyone on here, people on the12volt.com and on sounddomain.com, and my dad for helping me build the whole thing!
Here is a post on another forum with some pictures http://www.the12volt.com/installbay/forum_posts.asp?TID=48412&PN=1
Here is a post on another forum with some pictures http://www.the12volt.com/installbay/forum_posts.asp?TID=48412&PN=1
Saw the picture:
Nice woodwork🙂
I have now done the calculations on the JL 8 W0 driver.
Conclusion: You have to build a very large horn to get good frequency response. I guess that the TL of yours is ten times smarter than building a new fridge.
Attached you'll find the frequency responce of a 2 meter horn with a mouth sized 1,2 * 0,6 meter. I got 5 dB more efficiency of a 3 meter version with a mouth sized 1,2 * 1,2 meter.
Both designs are sideloaded open air versions. Tried to calculate in a chamber but the motorsystem is way to weak on the JL driver.
If you want to build one of them, I can give you enough info to make it and maybe a drawing.
Do you have a frequency response chart on your TL box?
Nice woodwork🙂
I have now done the calculations on the JL 8 W0 driver.
Conclusion: You have to build a very large horn to get good frequency response. I guess that the TL of yours is ten times smarter than building a new fridge.
Attached you'll find the frequency responce of a 2 meter horn with a mouth sized 1,2 * 0,6 meter. I got 5 dB more efficiency of a 3 meter version with a mouth sized 1,2 * 1,2 meter.
Both designs are sideloaded open air versions. Tried to calculate in a chamber but the motorsystem is way to weak on the JL driver.
If you want to build one of them, I can give you enough info to make it and maybe a drawing.
Do you have a frequency response chart on your TL box?
Attachments
Thank you.
I downloaded the TL math cad sheet off of quarter-wave.com but couldn't figure it out. I had been looking at horns for a while but someone helped me make a TL box, so I built one. This is only my second box but I will probobly carpet it and actually put a terminal cup on the side instead of a wire hanging out 🙂
I don't have a frequency response graph but the line (from the center of the woofer magnet) to the opening of the box is about 63 inches.
Here are the dimensions for the box:http://img.photobucket.com/albums/v521/customsuburb/transmissionlinebox.jpg
I downloaded the TL math cad sheet off of quarter-wave.com but couldn't figure it out. I had been looking at horns for a while but someone helped me make a TL box, so I built one. This is only my second box but I will probobly carpet it and actually put a terminal cup on the side instead of a wire hanging out 🙂
I don't have a frequency response graph but the line (from the center of the woofer magnet) to the opening of the box is about 63 inches.
Here are the dimensions for the box:http://img.photobucket.com/albums/v521/customsuburb/transmissionlinebox.jpg
Hi, I ran a calculation of the TL box and it is quite similar to the horn from 40 to 70 Hz, but it seems like there would be a dip with center frequency at 100 Hz and a really loud top with center frequency at ca 150 Hz.
In the calculation program I had to make the TL a straight line, so it is possible that the problems are much smaller with the bends.
You can try to find this out with sinus tones and your ears.
If 100 Hz has significantly decreased volume and 150 Hz the opposite, you should consider to set your crossover lower than 90Hz.
Where do you set your crossover point at the moment?
Good luck with your project🙂
In the calculation program I had to make the TL a straight line, so it is possible that the problems are much smaller with the bends.
You can try to find this out with sinus tones and your ears.
If 100 Hz has significantly decreased volume and 150 Hz the opposite, you should consider to set your crossover lower than 90Hz.
Where do you set your crossover point at the moment?
Good luck with your project🙂
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