Hi Oracles.
I have designed a 2½ way speaker using these components.
The speaker is active, and I have designed the electronics my self. I feel pretty good in the electronic part, but enclosure is not my favorite. The speakers are finished, and I have uploaded some pictures PICASA
The volume is 8.1 liter without all the electronic parts and damping material. The woofer is mounted in the bottom playing downward, but sharing room with the midrange speaker, that acutally also plays the low freq region due to the 2½ way concept.
My problem is that I have no bass in the sound. I have obviously designed somehing wrong? Is it the volume of the speaker, or what did I do wrong.
The bass port is changeable, but at the moment 11cm long, 3cm wide.
I hope some of you can help me with the problem, and eventually suggest some design modifications?
I have designed a 2½ way speaker using these components.
The speaker is active, and I have designed the electronics my self. I feel pretty good in the electronic part, but enclosure is not my favorite. The speakers are finished, and I have uploaded some pictures PICASA
The volume is 8.1 liter without all the electronic parts and damping material. The woofer is mounted in the bottom playing downward, but sharing room with the midrange speaker, that acutally also plays the low freq region due to the 2½ way concept.
My problem is that I have no bass in the sound. I have obviously designed somehing wrong? Is it the volume of the speaker, or what did I do wrong.
The bass port is changeable, but at the moment 11cm long, 3cm wide.
I hope some of you can help me with the problem, and eventually suggest some design modifications?
A 4" driver in an 8 liter box will never give much bass.
I'd start with a 6" as a minimum to approach anything labeled bass.
I'd start with a 6" as a minimum to approach anything labeled bass.
Hi Dexter, try disconnecting the lower woofer first and set up your system as a 2 way. See if there is enough bass.
In a 2.5way design, you generally use 2 identical midwoofers. I don't understand why you used a different one. (paper and nomex).
Each Wavecor midbass needs at least 5.5L for satisfying bass, so 8.1L is a little small for both of them.
In a 2.5way design, you generally use 2 identical midwoofers. I don't understand why you used a different one. (paper and nomex).
Each Wavecor midbass needs at least 5.5L for satisfying bass, so 8.1L is a little small for both of them.
Hi Dexter, as the parameters for the two 4 1/2" drivers are fairly similar I averaged them and put them into unibox. I figured that with the drivers volume taken into account, + the electronics you were probably down to about 7L volume for the two drivers.
The 11cm vent will give you a tuning frequency around 65Hz. Dropping the tuning to 54Hz (17.5cm vent) looks like it will give a better response. See attached. dark blue is with the 11cm vent. violet with the 17.5cm vent.
Have you checked to make sure that both woofers are in phase? if they are out of phase it will certainly affect the bass!
Tony.
The 11cm vent will give you a tuning frequency around 65Hz. Dropping the tuning to 54Hz (17.5cm vent) looks like it will give a better response. See attached. dark blue is with the 11cm vent. violet with the 17.5cm vent.
Have you checked to make sure that both woofers are in phase? if they are out of phase it will certainly affect the bass!
Tony.
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Hi guys.
Thank you for spending time for suggesting improvements.
Old'n'Cranky>> A 6" driver would probably do a better job, but as you see in the pictures, this is a little to late 🙂. I am aware that 4" drivers are not designed for bass, but I think I should be able to get some more out of them, than I do at the moment.
chlorofille>> The two drivers are almost identical, so I did not find this as a problem. The paper one, has a better performance in the >1000 range, and that is why I choose that one for mid range.
wintermute>> Thank you for simulating my system in unibox. I will try to increase the length of my vent. They are in phase, so this should not be a problem. Would it help me if i decreased the diameter of the vent?
Thank you for spending time for suggesting improvements.
Old'n'Cranky>> A 6" driver would probably do a better job, but as you see in the pictures, this is a little to late 🙂. I am aware that 4" drivers are not designed for bass, but I think I should be able to get some more out of them, than I do at the moment.
chlorofille>> The two drivers are almost identical, so I did not find this as a problem. The paper one, has a better performance in the >1000 range, and that is why I choose that one for mid range.
wintermute>> Thank you for simulating my system in unibox. I will try to increase the length of my vent. They are in phase, so this should not be a problem. Would it help me if i decreased the diameter of the vent?
Decreasing the diameter of the vent will push the port resonance higher and allow you to use a shorter port for the same tuning frequency. The downside is that it will increase the likelyhood of port noise.
With a 2cm diameter port you would only need a 7.3cm port for 54Hz tuning. Whether it is an issue or not depends on how much power you are feeding them. 3cm is marginal with 20W input.
Another question... what frequency are you rolling off the downfiring woofer? Is it around the baffle step frequency?
edit: and another. Are you using any attenuation on the tweeter?
Tony.
With a 2cm diameter port you would only need a 7.3cm port for 54Hz tuning. Whether it is an issue or not depends on how much power you are feeding them. 3cm is marginal with 20W input.
Another question... what frequency are you rolling off the downfiring woofer? Is it around the baffle step frequency?
edit: and another. Are you using any attenuation on the tweeter?
Tony.
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Ports don't always behave the way the formula says they should. It's safest to measure the tuning and then adjust the port length accordingly.
If you're doing active, though, there's a lot to be said for subwoofers. 200 to 300 mm cones can move more air with less effort.
If you're doing active, though, there's a lot to be said for subwoofers. 200 to 300 mm cones can move more air with less effort.
download the jeff b's woofer box simulation, you can learn your prblem and prb find the solution.
Have you checked the frequency response / voltage level distribution from the input to the individual amp outputs to make sure you are getting the correct levels . Assuming you have an individual amp for each driver are the gains of these the same . 3 way electronic crossover ?
epicyclic>> yes I have checked this and verified that the filter performs as expected.
I have individual +/-6db adjustment on each channel, and they are adjusted.
I have by using a signal generator and my own ears, measured the resonance freq. to be something like 37Hz. This seems a little low.
Should I maybe increase my vent a little, to increase this?
I have individual +/-6db adjustment on each channel, and they are adjusted.
I have by using a signal generator and my own ears, measured the resonance freq. to be something like 37Hz. This seems a little low.
Should I maybe increase my vent a little, to increase this?
37Hz seems low considering the port size and length... However the modeling I did yesterday was wrong (I have just realized) 😱 . I actually had two ports configured so please ignore my previous post!!
The model says about 17.5cm for 37Hz. so if it is actually 11cm then perhaps we can work out an approximate length to try for a higher tuning.
49hz tuning (which looks good) calls for a 9.8cm port. so if we use the same ratio our port comes out at about 6.2cm. So you could perhaps try shortening the port to that and see how it goes.
New graph attached. dark blue is 37Hz tuning. violet is 49Hz tuning.
As dangus said ports don't always behave the way you expect, I found that with a little box I made for a 4" driver as well... I think probably the bigger the box the closer it is. My 70L vented cabinets are pretty much spot on. I don't know whether you can just cut by the ratio I have suggested or not..... I guess its a case of try it and see. perhaps just cut a cm off at a time and remeasure and see how it goes.
Tony.
The model says about 17.5cm for 37Hz. so if it is actually 11cm then perhaps we can work out an approximate length to try for a higher tuning.
49hz tuning (which looks good) calls for a 9.8cm port. so if we use the same ratio our port comes out at about 6.2cm. So you could perhaps try shortening the port to that and see how it goes.
New graph attached. dark blue is 37Hz tuning. violet is 49Hz tuning.
As dangus said ports don't always behave the way you expect, I found that with a little box I made for a 4" driver as well... I think probably the bigger the box the closer it is. My 70L vented cabinets are pretty much spot on. I don't know whether you can just cut by the ratio I have suggested or not..... I guess its a case of try it and see. perhaps just cut a cm off at a time and remeasure and see how it goes.
Tony.
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