hi,
i am going to do three way stereo speaker project. i use 8 ohms for low ,mid ,high frequencies . for low frequencies i want to use two 8 ohms woofers per channel in parallel configuration . so low frequency crossover will see 4 ohm load ,mid and high frequency crossover will see 8 ohm load.
i am not sure about this configuration . is it possible have this configuration?
i am going to do three way stereo speaker project. i use 8 ohms for low ,mid ,high frequencies . for low frequencies i want to use two 8 ohms woofers per channel in parallel configuration . so low frequency crossover will see 4 ohm load ,mid and high frequency crossover will see 8 ohm load.
i am not sure about this configuration . is it possible have this configuration?
With the right crossover, you could put something together. Ahh but there's the rub. The crossover. If you've never designed one, that would obviously be a problem Off-the-shelf crossovers are usually a waste of money so it wouldn't be recommended to go there. What you might do instead is investigate any one of the multitude of proven designs from Parts Express, Madisound, Troels Gravesen, or John Krutke.
Yes, this is OK. The crossover is the same -- except the component values change a little. Example, the resistor values and inductor values are half. Even better, you can simulate and it will be just as easy as having all 8 ohm
Three way TM-WW designs are very popular because a narrow cabinet can be used with two 8" woofers, but still have the high SPL and high efficiency of one 12" woofer. Htguide.com has a well reviewed TM-WW with modest cost Dayton drivers. A search will find several TM-WW designs with higher quality drivers.
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When I ran a simple WinISD sim of two Dayton RS225-8 aluminum cone woofers the data showed that a ported box with 3cuft generates -F3 ~32Hz, which provides strong stand-alone bass.
The Dennis Murphy Design. Most of this research can be used with a slightly differently shaped 2-cabinet TM-WW construction to fit your style/needs.
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When I ran a simple WinISD sim of two Dayton RS225-8 aluminum cone woofers the data showed that a ported box with 3cuft generates -F3 ~32Hz, which provides strong stand-alone bass.
The Dennis Murphy Design. Most of this research can be used with a slightly differently shaped 2-cabinet TM-WW construction to fit your style/needs.
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It's risky to have two 8ohm woofers in parallel because the impedance can drop to such a low level that they become difficult for your average amp to drive. Problem is you are crossing where the impedance is very low. If it were a 2 way with parallel midbass drivers, you'd be crossing much higher, where the impedance is also high.
Link to the htguide page
A Guide to HTguide.com Completed Speaker Designs.
As a starting point the Holtz Anthology mini would be worth looking. Similar to the speaker line source outlined.
Speaker Design Works
The Statement mini is also worth a look but uses two 6.5” woofers but they go pretty low.
A Guide to HTguide.com Completed Speaker Designs.
As a starting point the Holtz Anthology mini would be worth looking. Similar to the speaker line source outlined.
Speaker Design Works
The Statement mini is also worth a look but uses two 6.5” woofers but they go pretty low.
thank you, i have designed three way with single woofer per channel but woofer spl is low to my taste and i have to boost bass frequency in preamp . again thank you for your reply i will go for two woofer per channel for higher spl ..
For a production speaker like the Nuance 3CL, the crossover, box volume, port tuning and voicing are optimized for 2-woofers, and I would expect very poor results and possible component damage if a third woofer is just cut into the baffle and wired in. Plus, three Re<7ohms woofers in parallel will have a very low impedance, below 3-ohms, which very few amplifiers can drive. You would probably need to wire two woofers in series which will have poor results.
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A new 3-woofer design would probably build a 3.5-way in a larger cabinet where the 3rd near-floor woofer only produces the lowest below baffle-step frequencies by using an additional inductor connected to the crossover off the upper two woofers. To minic a point source, the maximum separation between the midrange and all of the woofers should be near 1/4 the wavelength of the crossover frequency, which is difficult to achieve with 3-woofers. one 4-ohm and two 8-ohm woofers could be used to maintain a reasonable impedance
I have been experimenting with the crossover to remove the very boomy character of these speakers. The use of several small 10w resistors has flattened the bass response at the cost of 30hz performance. System impedance is at 7.5 ohms. I was thinking of adding the third woofer with a 8 ohm series resistor in the bottom position to follow the impedance as it spikes at 35Hz. new Z = 5 ohms at 20 hz worst case
I was wondering what effect the 3rd woofer has on the box response.
I was wondering what effect the 3rd woofer has on the box response.
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You can experiment with moving the speakers away from the walls and into the room to decrease the wall-reinforcement bass gain. There are free simulation tool like Baffle Edge Diffraction Simulator By Jeff Bagby Version 1.20 to illustrate room effects.
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You can research 2.5-way designs, where one crossover direct drives only the top woofer, and another inductor is added to the crossover and only drives the bottom woofer at a lower crossover frequency. You will need to measure the resistance of your woofer to calculate an inductor value. Only a good simulation can determine the value of the two inductors. If you only want to purchase one inductor for experimenting, put the original inductor on the lower woofer, and a new inductor of 25% that inductance on the top woofer.... seems safe.
I tend to disagree with that, it depends on what you are trying to accomplish. Granted a well built crossover, well designed will beat a sore bought, but by how much?
To me selection of the drivers is far more crucial to a good end result and for a beginner a store bought crossover may be a better way to go. Its a learning curve we all have to go through and how deep do we really want to get.
I could run a simulator and it will tell me what components I need for my crossover. Then I can find the same or similar crossover pre-made.
With out the tools to analyze each speaker and a good program to do the calcs, its going to be hit and miss.
Back in the 70's when I first started this, I spent a fortune on the tools, Oscope, signal generator and such and spent hours trying to get all the measurements I could. Now I can get the same stuff in a few minutes.
Its the journey of DIY, we don't need to hit perfect on the first try, close enough keeps the goal in sight and we keep trying for better.
Here's an analogy: let's say a shock absorber is like a crossover. And all the different makes and models of cars represent different drivers. What's the possibility of an individual shock absorber working on all the different cars. Just like a stock crossover being used on different drivers. It will work, but not very well.
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