I want to make a set of Totem Mites. I have the information about the size of the enclosure and the port width and length and also the drivers used.
The Tonsil GDN 13/40/2 (the woofer in the Mite) comes as 8 ohm or 4 ohm. After doing a few online calculations, it appears that they must use the 4 ohm driver, as all the calculations I did give a box size of about 5.6l, which is exactly the same as the Mite's volume. If I insert the 8 ohm driver's specs into the online calculators, the box size comes out as 10.7 litre.
The Totem website says the Mit's impedance is 8ohm!
What is the best way to go about designing the crossover for different impedance drivers? Is it just a case of using an L-Pad resistor network to get the SPL of the tweeter to match the woofer and then use a series resistor in line with the woofer to make the impedance 8 ohms, then carry out the usual crossover calculations?
Thanks in advance
The Tonsil GDN 13/40/2 (the woofer in the Mite) comes as 8 ohm or 4 ohm. After doing a few online calculations, it appears that they must use the 4 ohm driver, as all the calculations I did give a box size of about 5.6l, which is exactly the same as the Mite's volume. If I insert the 8 ohm driver's specs into the online calculators, the box size comes out as 10.7 litre.
The Totem website says the Mit's impedance is 8ohm!
What is the best way to go about designing the crossover for different impedance drivers? Is it just a case of using an L-Pad resistor network to get the SPL of the tweeter to match the woofer and then use a series resistor in line with the woofer to make the impedance 8 ohms, then carry out the usual crossover calculations?
Thanks in advance
I'm sure others will correct me if I'm wrong, but I see no connection between driver impedance and box size?
The functional cabinet size is related to Vas, and the frequency you want the box to resonate at. Which in this case is about 53hz.
Next, it is next to unheard of to put a resistor in series with the bass driver. I wouldn't say never, but it is rare. Just build the crossover to match the drivers.
http://totemacoustic.com/en/hi-fi/compact/mite/specifications/
Just a thought, which other can correct as needed.
Steve/bluewizard
The functional cabinet size is related to Vas, and the frequency you want the box to resonate at. Which in this case is about 53hz.
Next, it is next to unheard of to put a resistor in series with the bass driver. I wouldn't say never, but it is rare. Just build the crossover to match the drivers.
http://totemacoustic.com/en/hi-fi/compact/mite/specifications/
Just a thought, which other can correct as needed.
Steve/bluewizard
In fact both versions are very different. Only thing in common is that they share the same Fs (53Hz).
Tonsil GDN 13/40/2 8 ohm - GDN 13/40/2 :: Tonsil - Sklep internetowy e-tonsil
Tonsil GDN 13/40/2 4 ohm - GDN 13/40/2 4 ohm :: Tonsil - Sklep internetowy e-tonsil
T/S parameters like impedance, Vas, Qts and Xmax (gap is the same/height of coil is different) are all different in this case. This will inevitably give a different enclosure as a result.
OP, you can design a crossover for different impedances, just use the right one for each of the stages.
Example: For a 8ohm woofer start with a 8ohm crossover for low pass, for a 4ohm tweeter start with a 4ohm crossover high pass. This is the usual, if the opposite reverse impedances, for 4ohm woofer start with a 4ohm crossover for low pass, for a 8ohm tweeter start with a 8ohm crossover high pass. For 6ohm impedance procede in the same way. You should then simulate (SPICE software or spreadsheets) and test with drivers and components (models) for YOUR final work and MODIFICATIONS before auditioning.
Tonsil GDN 13/40/2 8 ohm - GDN 13/40/2 :: Tonsil - Sklep internetowy e-tonsil
Tonsil GDN 13/40/2 4 ohm - GDN 13/40/2 4 ohm :: Tonsil - Sklep internetowy e-tonsil
T/S parameters like impedance, Vas, Qts and Xmax (gap is the same/height of coil is different) are all different in this case. This will inevitably give a different enclosure as a result.
OP, you can design a crossover for different impedances, just use the right one for each of the stages.
Example: For a 8ohm woofer start with a 8ohm crossover for low pass, for a 4ohm tweeter start with a 4ohm crossover high pass. This is the usual, if the opposite reverse impedances, for 4ohm woofer start with a 4ohm crossover for low pass, for a 8ohm tweeter start with a 8ohm crossover high pass. For 6ohm impedance procede in the same way. You should then simulate (SPICE software or spreadsheets) and test with drivers and components (models) for YOUR final work and MODIFICATIONS before auditioning.
Thanks for the replies. I don't understand why Tonsil would make 2 drivers of different impedance with completely different characteristics.
Totem's website says the Mite is 8ohm impedance. Surely with a 4ohm woofer and 8ohm tweeter, it should be 6ohm. Anyway, if I work out an L-Pad resistor network for the tweeter and then work out the crossover for each I should be OK, right?
Totem's website says the Mite is 8ohm impedance. Surely with a 4ohm woofer and 8ohm tweeter, it should be 6ohm. Anyway, if I work out an L-Pad resistor network for the tweeter and then work out the crossover for each I should be OK, right?
The Mite uses the lower Qts version of the Tonsil woofers... (I know because I've designed them ), the GDN 13/40/2 4-ohm. You should not worry about impedance differences too much, because of the higher sensitivity of the tweeter, it has a series resistor before the high-pass section , so even if you use the 4 ohm woofer, the impedance will be roughly equal for the tweeter part. Anyway, if you check the impedance curves of most speakers, they show a quite wide fluctuation in their impedance, from the minimum of the woofer imp. (3-4 ohm), up to the 20-40 ohm region, specially if they are not compensatad for impedance. (The Mite is not.....) It uses a simple 5 part 2-nd order X-over (2 coils, 2 caps, one resistor).
), the GDN 13/40/2 4-ohm. You should not worry about impedance differences too much, because of the higher sensitivity of the tweeter, it has a series resistor before the high-pass section , so even if you use the 4 ohm woofer, the impedance will be roughly equal for the tweeter part. Anyway, if you check the impedance curves of most speakers, they show a quite wide fluctuation in their impedance, from the minimum of the woofer imp. (3-4 ohm), up to the 20-40 ohm region, specially if they are not compensatad for impedance. (The Mite is not.....) It uses a simple 5 part 2-nd order X-over (2 coils, 2 caps, one resistor).Attachments
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Hi,
Online calculators will never give the right x/o.
The x/o in post #8 is at 2.5KHz as shown.
rgds, sreten.
http://sites.google.com/site/undefinition/diy
(see if nothing else, the excellent FAQs)
The Speaker Building Bible
Zaph|Audio
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
http://audio.claub.net/Simple Loudspeaker Design ver2.pdf
FRD Consortium tools guide
Designing Crossovers with Software Only
RJB Audio Projects
Jay's DIY Loudspeaker Projects
Speaker Design Works
http://www.htguide.com/forum/showthread.php4?t=28655
A Speaker project
DIY Loudspeakers
Humble Homemade Hifi
Quarter Wavelength Loudspeaker Design
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
Linkwitz Lab - Loudspeaker Design
Music and Design
Great free SPICE Emulator : SPICE-Based Analog Simulation Program - TINA-TI - TI Software Folder
Online calculators will never give the right x/o.
The x/o in post #8 is at 2.5KHz as shown.
rgds, sreten.
http://sites.google.com/site/undefinition/diy
(see if nothing else, the excellent FAQs)
The Speaker Building Bible
Zaph|Audio
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
http://audio.claub.net/Simple Loudspeaker Design ver2.pdf
FRD Consortium tools guide
Designing Crossovers with Software Only
RJB Audio Projects
Jay's DIY Loudspeaker Projects
Speaker Design Works
http://www.htguide.com/forum/showthread.php4?t=28655
A Speaker project
DIY Loudspeakers
Humble Homemade Hifi
Quarter Wavelength Loudspeaker Design
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
Linkwitz Lab - Loudspeaker Design
Music and Design
Great free SPICE Emulator : SPICE-Based Analog Simulation Program - TINA-TI - TI Software Folder
As i wrote in my previous post, it is NOT the Mite's x-over, but the one in it is VERY similar to it. If not almost the same..... The x-over freq. shown is 2.5k, it is the same as of the Mite. I cannot help you more, but you can play with slightly different values, according to your personal sonic preference.
. The x-over freq. shown is 2.5k, it is the same as of the Mite. I cannot help you more, but you can play with slightly different values, according to your personal sonic preference.Thanks for the help guys.
I've never built a 2 way speaker before. I did build a set of fullrange speakers. They were 'The Derwent' cabinets with CSS EL70 drivers, great sound. I did add a supertweeter which I designed the crossover myself. As for 2 way speakers, I better keep reading
Edit:
I've tried several online crossover calculators and I don't get values anywhere near what the diagram in post #8 shows. Can someone explain it? Thanks
I've never built a 2 way speaker before. I did build a set of fullrange speakers. They were 'The Derwent' cabinets with CSS EL70 drivers, great sound. I did add a supertweeter which I designed the crossover myself. As for 2 way speakers, I better keep reading
Edit:
I've tried several online crossover calculators and I don't get values anywhere near what the diagram in post #8 shows. Can someone explain it? Thanks
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For example, using this crossover design calculator Crossover Design Calculators and inserting the crossover frequency at 2.5KHz
4ohm woofer:
Linkwitz - 7.96uF and 0.51mH
Butterworth - 11.25uF and 0.36mH
Bezzel - 9.12uF and 0.44mH
8ohm woofer:
Linkwitz - 3.98uF and 1.01mH
Butterworth - 5.63uF and 0.72mH
Bezzel - 4.56uF and 0.88mH
How do you get the values in the diagram? Also, is there a calculation for working out the crossover frequency being given the inductor value and the capacitor value?
4ohm woofer:
Linkwitz - 7.96uF and 0.51mH
Butterworth - 11.25uF and 0.36mH
Bezzel - 9.12uF and 0.44mH
8ohm woofer:
Linkwitz - 3.98uF and 1.01mH
Butterworth - 5.63uF and 0.72mH
Bezzel - 4.56uF and 0.88mH
How do you get the values in the diagram? Also, is there a calculation for working out the crossover frequency being given the inductor value and the capacitor value?
It would seem from what I'm reading that if you use the crossover in post 8 you'll probably be within tweaking distance of a good crossover.
Anyway, filter components are essentially chosen to work with the driver impedance, which varies. In other words if you take a text book set of values and combine them with appropriate impedance compensation, you'll no longer need separate compensation but the filter will seem to have weird values. It's all good.
Anyway, filter components are essentially chosen to work with the driver impedance, which varies. In other words if you take a text book set of values and combine them with appropriate impedance compensation, you'll no longer need separate compensation but the filter will seem to have weird values. It's all good.
1/(2*pi*sqr(L*C)) will get you the resonance frequency of the filter. This may be close to the actual crossover point but it will be dependent on such things as the driver response, and the Q of the filter.
That gives 1299 for the woofer and 4238 for the tweeter! Surely the driver impedance needs to be in the calculation!
Also, regarding one of the links Dizzi posted http://www.speakerlab.gr/papers/totem_REB.pdf. Here the guy has replaced the 4ohm driver with the 8ohm version. How could the 8ohm version work in the same box? As mentioned earlier, all of the values for the two version of the driver are different. The 4ohm version needs something like a 5.6l box and the 8ohm version needs about 10 or 11 l box.
Also, regarding one of the links Dizzi posted http://www.speakerlab.gr/papers/totem_REB.pdf. Here the guy has replaced the 4ohm driver with the 8ohm version. How could the 8ohm version work in the same box? As mentioned earlier, all of the values for the two version of the driver are different. The 4ohm version needs something like a 5.6l box and the 8ohm version needs about 10 or 11 l box.
In the real world crossover design is much more experiment- based, because calculated values work only with constant impedance drivers, and the real ones are more than far from that. I happen to know this, because I did it for about 20 years. Also different impedance drivers with different T-S data can fit into lots of different size boxes, as it is splendidly demonstrated in an old Speaker Builder issue by Ralph Gonzalez (titled: Quasi-Monotonic vented alignments). Speaker design software are a good starting point, but usually have limited use when it comes to real-world drivers. SBB4, B4, C4 (the most commonly used alignments) are limited to only one box size each with a given driver, while QM3 gives you much more versatility by tuning the box to different frequencies.
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OK, there seems a lot more too it than it first appears.
Dragonweed, would the crossover shown in post #8 work with the GDN 13/40/2 8ohm or 4ohm version and as for the tweeter, should I use the GDWK 11/100 (8ohm)
Sorry for all of the questions, thanks again
I still don't understand the box volume staying the same when using the 8 ohm version of the driver instead of the 4 ohm version in the link Dizzi posted.
I also found this build using the same drivers:
http://diyaudio.pl/showthread.php/14109-2-way-by-EZO-gdn13-40-2-8-gdwk-11-100
How would you work out the crossover frequency in his crossover design
Dragonweed, would the crossover shown in post #8 work with the GDN 13/40/2 8ohm or 4ohm version and as for the tweeter, should I use the GDWK 11/100 (8ohm)
Sorry for all of the questions, thanks again
I still don't understand the box volume staying the same when using the 8 ohm version of the driver instead of the 4 ohm version in the link Dizzi posted.
I also found this build using the same drivers:
http://diyaudio.pl/showthread.php/14109-2-way-by-EZO-gdn13-40-2-8-gdwk-11-100
How would you work out the crossover frequency in his crossover design
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Use the GDWK 13/40 8 ohm version in a 5.6-6 liter box. Don't worry it will work well, because it uses QM3 alignment in the reflex tuning-("undertuned"). I do not work for Totem since 2000, I designed most of their products, but I have no right to publish the details of their designs, and I wouldn't do it anyway.......). Just suggesting, the values in post#8 are quite useful , so you can start from there.
Thanks very much
I'll stick with a 5.6l box and the same port as the Mite and use the crossover shown and see what happens. I can always tweak them afterwards. This will be a nice stereo setup paired with my DIY amp.
I was looking also at the Totem Sttaf, as a friend of mine has a pair which sound great and he said I could take some internal measurements from them. These use the same drivers also, so I want to eventually build a pair of Sttafs and a single Mite to use in my home cinema set-up. Would the crossover described earlier work well, or should I redesign it?
I'll stick with a 5.6l box and the same port as the Mite and use the crossover shown and see what happens. I can always tweak them afterwards. This will be a nice stereo setup paired with my DIY amp.
I was looking also at the Totem Sttaf, as a friend of mine has a pair which sound great and he said I could take some internal measurements from them. These use the same drivers also, so I want to eventually build a pair of Sttafs and a single Mite to use in my home cinema set-up. Would the crossover described earlier work well, or should I redesign it?
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